JP6923341B2 - Operating point control circuit for photovoltaics and series-connected solar cells or other power sources - Google Patents

Description

The present invention relates to a photovoltaic power generation device in which a plurality of solar cells are connected in series or a power output device in which any other power source (battery, power storage, fuel cell, generator, thermoelectric element, etc.) is connected in series. More specifically, the present invention relates to a circuit device (operating point control circuit device) that controls the operating points of solar cells or other power sources connected in series.

Since the generated voltage of one solar cell (cell) is generally lower than the operating voltage of various machinery / equipment and chargers, the solar cell is used for operating such machinery / equipment and charging the charger. As one of the methods, in a photovoltaic power generation system, a configuration in which a plurality of solar cell cells are connected in series (solar cell module) is adopted. In the solar cell module, if the installation angle of each solar cell is different or a building or the like causes a shadow on some cells and the amount of light received varies from cell to cell, the cell with a small amount of power generation resists. It becomes (reverse bias diode) and can reduce the output of the solar cell module.

More specifically, with reference to FIG. 1, as is well known in the art, a solar cell receiving a certain amount of light is used until the generated voltage increases from 0 V to a certain value. Has a power generation voltage-current characteristic in which the current sharply decreases as the current (fine solid lines I _{100 to I 25) gradually decreases and the power generation voltage further increases.} Therefore, the generated power of the solar cell (thick solid line P _{100 to} P ₂₅ ) exhibits a characteristic that changes in a chevron shape with respect to the generated voltage, and the optimum operating point (maximum power point or optimum) at which the magnitude of the generated power is maximized. There is an operating point). Then, as shown in the figure, as the amount of light received by the solar cell decreases (R = 100% → R = 25%), the generated voltage-current characteristic decreases the _{current (I 100} → I _{25) with respect to the generated voltage.} Therefore, the generated power (P ₁₀₀ → P ₂₅ ) decreases, and the maximum output point also changes. In the case of a circuit configuration in which a plurality of solar cells having such characteristics are simply connected in series as they are, a common current flows through all the solar cells, so that the amount of light received by all the solar cells is substantially reduced. When they are equal and their maximum output points are substantially the same, the currents at the maximum output points are equal and all solar cells can be operated at the maximum output points. If the amount of light received by some of the solar cells in the solar cell module is reduced due to shadows, etc., the solar cells with the reduced amount of light will flow the same current as the cells with a large amount of light received. The operating point deviates from the maximum output point, the amount of power generated is reduced to a greater extent than corresponding to the reduction in the amount of light received, and the solar cell itself with the reduced amount of light received is resistant to such current. Therefore, the output of the solar cell module is further reduced. (That is, not only the maximum power generation output corresponding to the amount of light received by the solar cell module cannot be obtained, but also output loss occurs.)

Therefore, as a device for avoiding a decrease in output due to a variation in the amount of light received for each solar cell in such a solar cell module, each solar cell connected in series is individually patented. A power generation operating point control circuit device capable of being controlled is proposed (Non-Patent Documents 1 to 3). Such a power generation operation point control circuit device is different from each other by controlling the power generation voltage for each solar cell by using a multi-stage buck-boost chopper circuit for a circuit configuration in which a plurality of solar cells are connected in series. It is possible to circulate current, which allows current to circulate in each solar cell at its maximum output point, even if the amount of light received by a plurality of solar cells connected in series is different. The generated voltage is adjustable so that all solar cells can generate electricity at substantially the maximum output point. That is, according to this power generation operating point control circuit device, even a solar cell whose light receiving amount is reduced due to shadows or the like can be operated at its maximum output point, so that it corresponds to the light receiving amount of the entire solar cell module. As a result, the maximum generated power can be obtained substantially, and since the solar cell whose light receiving amount is reduced does not become a reverse bias diode, output loss can be avoided.

JP 2016-214061

Toshihisa Shimizu and 6 others, Proceedings of Solar / Wind Energy Lectures, 1996, pp. 57-60 Toshihisa Shimizu, FB Technical News No. 56 November 1, 2000, pp. 22-27 Toshihisa Shimizu and 3 others, "Generation Control Circuit for Photovoltaic Modules" IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL.16, NO. 3, MAY 2001, pp. 293-300

In a solar cell module in which a plurality of solar cells are connected in series, when the power generation operating point control circuit device as described above is used to optimally control each power generation operating point of the solar cells, It will take some time and effort to search for those power generation operating points. In the case of such a power generation operating point control circuit device, specifically, ON / OFF (conduction / conduction /) of a switching element or a switching means connected in parallel to each of the solar cells connected in series between the output terminals. The operation of raising or lowering the power generation voltage (operating voltage) of each of the solar cells is executed by adjusting the ratio (duty ratio) of the time length (cutoff). For example, for each of the n solar cells connected in series, if two operations of stepping up and lowering the generated voltage are executed k times in order to search for the operating point of power generation, 2 nk ways of searching are performed. It will take a number of times. Therefore, as the number of solar cells increases, the time required for the search control of the power generation operating point that follows the fluctuation of the light receiving amount of each solar cell becomes longer.

By the way, referring to FIG. 1 again, as described above, when the amount of light received by the solar cell decreases (R = 100% to 25%), the generated power (P _{100 to} P ₂₅ ) with respect to the generated voltage tends to decrease. The characteristics change, and the maximum power point (x) changes as shown by the dotted line in the figure. _{The power value (P 100 to} P ₂₅ ) and the current value (I _{100 to} I ₂₅ ) change significantly in the change in the characteristics with respect to the reduction in the amount of received light, whereas the voltage value (x) at the maximum power point. It was found that the range of change is relatively small, and that the change in the generated power value with respect to the change in the voltage value near the maximum power point is also relatively gradual in the generated power characteristics for each received light amount. Is done. More specifically, for example, as shown in the figure, when there is a solar cell whose light receiving amount R is reduced from 100% to 75%, 50%, and 25%, all of those generated voltages are received. Even if it is adjusted to the _{power generation voltage (single point chain line: Vmpp100} ) at the maximum power point of the solar cell (R = 100%) having the maximum amount, the power generated with respect to the power at the maximum power point of each solar cell. It is understood that the amount of reduction of (P ₇₅ , P ₅₀ , P ₂₅ ) is about ΔP1, ΔP2, and ΔP3 as shown in the figure, and does not increase so much. That is, in the solar cell module, the generated power and / or the generated voltage is adjusted so that each solar cell operates at the maximum power point according to the change in the amount of light received by each solar cell. rather than perform an operation that, rather, the power generation voltages of all of the solar cell to a certain value, for example, is fixed to the power generation voltage value of the maximum power point of the maximum of the solar cell of the light-receiving amount _{(V mpp100)} Although there will be a small loss of power due to this, it may be advantageous because it saves a lot of time and effort for adjusting the generated power and / or the generated voltage of each solar cell. .. The generated voltage of each solar cell is determined by the duty ratio of the switching element or the switching means connected in parallel to each of them and the voltage between the output terminals of the solar cell module. Therefore, the duty ratio of the switching element or the switching means. Even if is set to a fixed value, the generated voltage of each solar cell can be adjusted as described above by adjusting the voltage between the output terminals. This finding is utilized in the present invention.

Thus, one major subject of the present invention is in a solar cell module in which a plurality of solar cell cells are connected in series, the generated power and / or the generated voltage of each solar cell, or a switching element or a switching element. It is an object of the present invention to provide a photovoltaic power generation device or a power generation operation point control circuit device that can significantly reduce the time and labor spent for adjusting the duty ratio of the switching means. The "power generation operating point control circuit device" is a circuit part for controlling the power generation voltage and current of each of the solar cells connected in series (connection terminal to the solar cell, switching element, capacitor, inductor). Etc.), and the term "photovoltaic power generation device" refers to a device having a configuration including a solar cell module composed of solar cells connected in series and a power generation operating point control circuit.

Further, it is preferable that the power generation operation control of the solar cell of the solar cell module using the above-mentioned solar power generation device or power generation operating point control circuit is more stable or has less loss. Therefore, another object of the present invention is to provide a configuration of a photovoltaic power generation device or a power generation operating point control circuit device that operates more stably and / or with less loss.

By the way, the circuit configuration of the device according to the present invention, which will be described in more detail later, is not limited to solar cells, but is a power source element that outputs arbitrary power (for example, a chemical cell, a fuel cell, a capacitor, a generator, a thermoelectric element, etc.). It can also be used to control the operating voltage of each power source element in a module in which is connected in series. Therefore, a further subject of the present invention is an individual power source element (cell) in a module in which a plurality of solar cells and / or power source elements (battery cell, capacitor cell, generator, thermoelectric element, etc.) are connected in series. It is an operating point control circuit device that controls the operating point of the above, and is to provide a configuration capable of significantly reducing the time and labor required for adjusting the operating power and / or the operating voltage of each power source element.

According to the present invention, one of the above-mentioned problems is to connect a plurality of solar cells or a plurality of solar cells and a capacitor in series between the output terminals, and to connect each solar cell or each solar cell or a capacitor between the output terminals. Each solar cell and capacitor includes a power generation operating point control circuit device in which switching elements are connected in parallel via an inductor, and the corresponding solar cells are generated by periodically shutting off each of the switching elements. Alternatively, the photovoltaic power generation device that sends a current from the capacitor to the output terminals, and the power generation operating point control circuit device is the switching element corresponding to all of the plurality of solar cells or the plurality of solar cells and the capacitor. It is achieved by an apparatus characterized in that the duty ratio of the interruption to all the switching elements is fixed during one cycle of interrupting the circuit.

That is, in the above device, the power generation operating point control circuit device is connected to each electrode terminal of a plurality of solar cells connected in series between the pair of output terminals and the pair of output terminals. A capacitor and a pair of output terminals connected in parallel between a plurality of electrode connection terminals and a pair of output terminals via corresponding electrode connection terminals for each of a plurality of solar cells. In the meantime, for each of the plurality of solar cells, the corresponding electrode connection terminals and the inductors are connected in parallel, and the pair of connected electrode connection terminals are selectively electrically connected to each other. A conductive state in which each state of the switching means (that is, "switching element") and the switching means is conducted between the pair of electrode connection terminals or both terminals connected between the pair of terminals of the capacitor. It includes a control means for alternately switching between the above and the cutoff state in which the continuity between the two terminals is cut off at the same predetermined cycle. Then, with respect to the control of the series of switching means, the control means always controls so that at least a part of the switching means is in the cutoff state and the other switching means is in the conductive state, and all the predetermined cycles of the switching means are controlled. The ratio of the length of the cut-off state to the length (cut-off duty ratio) is uniformly fixed so as to be the same as each other. The power generation operating point control circuit device is further provided between the pair of output terminals, between the electrode connection terminal on one end side of a plurality of solar cells connected in series and one of the output terminals, or between the output terminals. An additional capacitor is connected in series with the capacitor between two electrode connection terminals between two adjacent solar cells among a plurality of solar cells connected in series. An additional switching means is connected in parallel to the additional capacitor and in series with the switching means, or to a capacitor connected in series between a pair of output terminals. On the other hand, an additional capacitor is connected in series, and an additional switching means is connected in parallel with the additional capacitor and in series with the switching means connected in series between the pair of output terminals. May be connected. In those cases, control of the switching means may be performed in the same manner as described above, including additional switching means and / or additional switching means.

The above-mentioned apparatus of the present invention, if necessary, has a circuit configuration of a multi-stage type described in Non-Patent Documents 1 to 3 as basically understood from the description with reference to the drawings described later. It has the same configuration as the power generation operating point control circuit device for a plurality of solar cells connected in series using a buck-boost chopper circuit. As described above, between one end of a multi-stage buck-boost chopper circuit (circuit consisting of a solar cell, a capacitor, an inductor, and a switching element) and one output terminal, or the stage of a multi-stage buck-boost chopper circuit. In between, additional circuitry may be added in which additional capacitors and additional switching means are connected in parallel, or additional capacitors and additional switching means may be added outside between the pair of output terminals. In this case, the circuit configuration may be simply described as one solar cell in the power generation operation point control circuit device of Non-Patent Documents 1 to 3. It is the same as the configuration with the cells removed.) Then, in the multi-stage buck-boost chopper circuit, the duty ratio for interrupting the switching element of each stage of the buck-boost chopper circuit is previously desired to be the generated voltage of the corresponding solar cell as described above. This operation took time, respectively, where the voltage was adjusted to (preferably the voltage at the maximum power point) or the voltage across the corresponding capacitor to the desired voltage. And labor was required.

On the other hand, in the case of the apparatus of the present invention, if necessary, the duty ratio of the cutoff of the switching element or the switching means of each stage of the buck-boost chopper circuit is uniformly fixed. This eliminates the need to perform an operation to adjust the duty ratio of the cutoff, significantly reducing the time and effort required to adjust the operating conditions of the device (later, more). As explained in detail, in order to improve the power generation efficiency, it is necessary to adjust the overall output voltage (voltage between output terminals) of the multi-stage buck-boost chopper circuit.) In the case of such a configuration, as will be described in detail later, the voltage applied in each stage of the multi-stage buck-boost chopper circuit, that is, the generated voltage of the solar cell (if there is an additional capacitor, the capacitor's voltage). The holding voltage is also included.) Is basically uniformly determined to a certain value, so that the operating point of each solar cell deviates from the maximum power point depending on the amount of light received. obtain. However, in the above-mentioned multi-stage buck-boost chopper circuit, the current flowing through each stage is individually determined according to the generated voltage-current characteristics depending on the amount of light received by each solar cell. In a solar cell, since the range of change in the generated power due to the change in the generated voltage is small with respect to the change in the amount of received light, the amount of decrease in the generated power due to the deviation of the generated voltage from the maximum power point is kept relatively small. Will be done. That is, according to the configuration of the present invention, it is possible to obtain an advantage that the time and labor required for adjusting the operating conditions of the apparatus can be reduced while suppressing the decrease in the generated power to be relatively small.

By the way, as already mentioned, the above-described configuration of the present invention is not limited to solar cells, but is a power supply element that outputs arbitrary power such as a chemical cell, a fuel cell, a capacitor, a generator, and a thermoelectric element (hereinafter, It can also be applied to control the operating voltage of each power cell in a module in which (referred to as "power cell") is connected in series. Therefore, in another aspect of the present invention, it is an operating point control circuit device for a plurality of power supply cells connected in series, and is connected in series between a pair of output terminals and the pair of output terminals. Between the plurality of electrode connection terminals connected to the respective electrode terminals of the plurality of power cells connected to the power cell and the pair of output terminals, the corresponding electrodes for each of the plurality of power cells. Between the capacitor connected in parallel via the connection terminal and the pair of output terminals, for each of the plurality of power cells, in parallel via the corresponding electrode connection terminal and inductor. A switching means that is connected and selectively conducts each other between the pair of connected electrode connection terminals and the state of each of the switching means can be set between the pair of electrode connection terminals or the capacitor. A control means for alternately switching between a conductive state in which both terminals connected between the pair of terminals are conductive and a cutoff state in which conduction between the two terminals is cut off, at the same predetermined cycle. Including, the control means always controls at least some of the switching means to be in the cutoff state and the other switching means to be in the conductive state, with respect to all the predetermined period lengths of the switching means. An apparatus is provided in which the ratio of the lengths of the cut-off states is uniformly fixed so as to be the same as each other. In such a configuration, further, between the pair of output terminals, between the electrode connection terminal on one end side of the plurality of power cells connected in series or between one of the output terminals or the said. An additional capacitor is connected in series with the capacitor between the two electrode connection terminals between two adjacent power cells of the plurality of power cells connected in series, and the additional capacitor is connected. An additional switching means may be connected in parallel with the capacitor and in series with the switching means, or the capacitor connected in series between the pair of output terminals. An additional capacitor is connected in series with the switching means, and an additional capacitor is added in parallel with the additional capacitor and in series with the switching means connected in series between the pair of output terminals. The switching means may be connected. Hereinafter, unless otherwise specified, the term "power cell" refers to a solar cell or other power element that outputs arbitrary power.

Regarding the switching control of the conduction / cutoff state of the switching element or the switching means in the above-mentioned apparatus of the present invention, in one embodiment, the cutoff times for all the switching elements in one cycle do not overlap with each other. It may be. That is, the state of the switching means may be controlled by the control means so that the timing of the cutoff state of all the switching means is different from each other. In this case, in the configuration of the apparatus of the present invention, by uniformly fixing the duty ratio of the cutoff, the operating voltage of each stage of the buck-boost chopper circuit (that is, the solar cell or other power supply cell or these) The generated voltage or operating voltage or holding voltage of each of the capacitors connected in series) is uniformly determined to be one value. And in such a configuration, the duty cycle of the cutoff includes the number of stages of the buck-boost chopper circuit, i.e., the switching means connected in series (additional switching means, if any additional switching means are present). Since it is the reciprocal of the number of.), The duty ratio of the cutoff can be easily adjusted. Further, in the case of this configuration, if necessary, the switching elements or the switching means are cut off one by one at a time. Therefore, this alone is the operating voltage of the stage of the buck-boost chopper circuit corresponding to each switching means. Can be determined stably.

Further, regarding the switching control of the conduction / cutoff state of the switching element or the switching means in the above-mentioned apparatus of the present invention, in another embodiment, the time length of the cutoff for all the switching elements in the one cycle. The sum may be greater than the temporal length of the one cycle, and the timing of the interruptions may be such that some of them overlap between adjacent interruptions. That is, the state of the switching means may be controlled by the control means so that the switching means that is temporarily cut off is two adjacent switching means. According to such a configuration, as will be described in detail in the column of the embodiment, as compared with the configuration in which the state of the switching means is controlled so that the time when all the switching elements or the switching means are cut off is different from each other. Therefore, the voltage applied to the switching element or the switching means when they are in the cutoff state is reduced, and therefore, it is advantageous in that the withstand voltage level required for the switching element or the switching means can be reduced. In this case, in the embodiment, the switching means that are temporarily cut off by the control means are two adjacent switching means, and the switching means that are cut off are connected in series. The state of the switching means may be controlled so as to sequentially shift from one end of the row to the other end. In this configuration, as will be explained later, in the switching means that has been cut off earlier, the presence of the parasitic diode allows only the flow of current in one direction, and therefore, it is substantially at one time. There is only one switching means that is in a cut-off state. Then, it is substantially the same as shutting off the switching elements or the switching means one by one at a time, and this alone stabilizes the operating voltage of the stage of the buck-boost chopper circuit corresponding to each switching means. It will be possible to make a decision.

Further, regarding the switching control of the conduction / cutoff state of the switching element or the switching means in the above-mentioned apparatus of the present invention, in another aspect, one of the cutoffs for all the switching elements in one cycle. The multiple cutoffs may be at the same time as each other. More specifically, the state of the switching means connected in series by the control means is such that all of the switching means connected in odd numbers from one of the rows of the switching means connected in series are cut off. The first phase in which all of the even-numbered switching means connected from one of the switching means rows are in a conductive state, and the odd-numbered switching means connected from one of the switching means rows are The control may be executed so that the switching means connected to the even number from one of the rows of the switching means in the conductive state is alternately switched to the second phase in the cutoff state. In this case, since the state of each switching means is switched between the first phase and the second phase, the cutoff duty ratios are all determined to be 1/2, and therefore the troublesome cutoff duty ratio. The time and effort required to adjust the is saved. Further, as will be described in detail later, since a plurality of switching means are cut off at the same time, the withstand voltage required for each switching means can be reduced, which is advantageous.

In particular, as described above, in the case of alternately switching the state between the two phases of the "first phase" and the "second phase" in the switching control of the conduction / cutoff state of the switching element or the switching means. More preferably, in the operating point control circuit device, the 2m-1st (m) counting from one of the n (n is a positive integer) sequence of switching means connected in series. Is on each of the ends of all the pairs of switching means (1st and 2nd pairs, 3rd and 4th pairs, ...) connected to the 2mth (all integers from 1 to n / 2). On the other hand, a voltage stabilizing capacitor is connected in parallel, and the set of the switching means connected to the 2i-2nd (i is all integers from 2 to n / 2) and the 2i-1st, counting from the one. A configuration may be adopted in which a voltage stabilizing capacitor is connected in parallel to each of both ends of all (second and third sets, fourth and fifth sets, ...). As will be described in detail later, the use of a "voltage stabilizing capacitor" has the advantage of making the operating voltage of each solar cell or other power cell more stable.

Further, in the embodiment of the operating point control circuit device of the present invention, among the rows of n switching means (n is a positive integer) connected in series, the 2m-1st (2m-1st) (counting from one). m is all integers from 1 to n / 2) and the connection point between the 2mth connected switching means and the connection point between the capacitors corresponding to the switching means, each of which is an inductor. To the connection point between the 2i-2nd (i is all integers from 2 to n / 2) and the 2i-1st connected switching means and the switching means. Everything between the connection points of the corresponding capacitors may be connected without an inductor. That is, as will be more easily understood with reference to the figures described later, in particular, the conduction / cutoff state of the switching element or the switching means is defined as two phases, a "first phase" and a "second phase". In the case of a control configuration that alternately switches the state between, counting from one side, between the 2i-2nd (i is all integers from 2 to n / 2) and the 2i-1st connected switching means. An inductor is not necessarily (or may be) required between the connection point and the connection point of the capacitor corresponding to the switching means, and thus in a series of wires connecting the switching means and the capacitor. Therefore, the inductors need only be provided every other one. Inductors have a higher parasitic resistance than ordinary conductors (for example, linear copper wires), so if the number of inductors used is reduced as described above, the output loss will increase accordingly. A reduction can be expected.

By the way, as described above, a circuit in which an additional capacitor and an additional switching means are connected in parallel to the buck-boost chopper circuit connected to each of the solar cells connected in series. When additional parts are connected, if the circuit part is connected between the output terminals, there is a period during which the output current flowing between the output terminals flows directly into the additional switching means, which depends on the switching means. Output loss will occur. On the other hand, in the configuration where the additional capacitor and the additional switching means are outside between the output terminals (when connecting the additional additional capacitor and the additional switching means), the additional switching means is provided with the output current. Does not flow, so the output loss there is greatly reduced. Such an additional circuit portion may be provided for the purpose of boosting the voltage between output terminals, as will be described later (see Patent Document 1). Thus, when a circuit portion is used in which an additional capacitor additionally connected to the buck-boost chopper circuit and an additional switching means are connected in parallel, such a circuit portion is used when the emphasis is on reducing output loss. Is added to the outside between the output terminals, and may be added to the inside between the output terminals when the boosting between the output terminals is emphasized.

Further, in the above-mentioned apparatus of the present invention, as already mentioned, the voltage of each stage of the buck-boost chopper circuit is determined by the cutoff duty ratio of the corresponding switching element or switching means and the voltage between output terminals. Of these, the sum of the generated voltage or operating voltage of the power supply cell in the stage sandwiched between the output terminals (if there is an additional capacitor, the sum of the holding voltage added) is between the output terminals. It will match the voltage. Then, as will be described later, since the duty ratio is uniformly fixed, the generated voltage, operating voltage, or holding voltage of the power cell or capacitor becomes equal to each other and becomes a function of the voltage between the output terminals.

Therefore, the voltage between the output terminals may be typically controlled by a voltage control device or an output voltage control means, and by adjusting the voltage between the output terminals, the power cell in the stage sandwiched between the output terminals. Alternatively, the generated voltage, operating voltage, or holding voltage of each of the capacitors may be adjusted. For example, when a solar cell is used as a power cell connected in series, the output terminal is such that the generated voltage of any one of the solar cells or the solar cell having the maximum light receiving amount becomes the voltage at the maximum operating point. The voltage between them may be adjusted. As a result, the generated voltage of the other solar cell matches the generated voltage of the solar cell having the maximum light receiving amount, and may deviate from the voltage of the maximum operating point depending on the received light amount. The deviation is relatively small, and therefore the reduction in output is also expected to be relatively small. In the case of a solar cell, the voltage control may be preferably executed by using a voltage or current controller such as an MPPT controller that executes maximum power point tracking (MPPT). .. Further, a voltage control means for transforming the voltage between the output terminals adjusted as described above so as to match the required voltage of the connected load may be connected between the output terminals. As a result, it is possible to drive or operate the load while operating the power supply cell in the optimum state as much as possible.

In the embodiment of the apparatus of the present invention, typically, the switching control of the conduction / cutoff state of the switching element or the switching means is controlled by a series of switching elements or the switching means as one unit. However, in another embodiment, the plurality of solar cells or the plurality of solar cells and the capacitor are divided into a plurality of units, and the power generation operating point control circuit device is individually provided for each of the plurality of units. Each may control the interruption of the switching element belonging to the unit. That is, a plurality of switching means may be divided into a plurality of groups, and the state of the switching means belonging to each of the plurality of groups may be controlled separately for each group. When the number of solar cells or power supply cells increases, and therefore the number of stages of the buck-boost chopper circuit increases, a series of switching elements or switching means is not controlled as one unit, but a series of switching elements or switching means. It may be advantageous to divide the group of means into a plurality of units and control them separately (although control processing is required separately). In that case, as described in the column of the later embodiment, as one of the embodiments, the plurality of solar cells or the plurality of solar cells and the capacitor share one of them at the boundary with each other. It may be divided into a plurality of units, and a power generation operating point control circuit device may be individually provided for each of the plurality of units, and each of them may control the interruption of the switching element belonging to the unit. That is, at least one power supply cell is connected in parallel to both one switching means in the first group and one switching means in the second group between the pair of output terminals. It may be.

Thus, in the above-described configuration of the present invention, a plurality of solar cells or a plurality of solar cells or in a device for controlling a generated voltage by using a multi-stage buck-boost chopper circuit for a plurality of solar cells connected in series. The duty ratio of the cutoff for all the switching elements is fixed during one cycle of shutting off the switching elements corresponding to all of the plurality of solar cells and the capacitors, in other words, the switching means. The duty ratio of the switching element or the switching means is fixed uniformly so that the ratio of the length of the period in which the cutoff state is established (the duty ratio of the cutoff) to the length of all the predetermined cycles of the above is the same as each other. The time and labor spent for adjustment becomes unnecessary, and the time and labor spent for adjusting the generated power and / or the generated voltage of each solar cell can be significantly reduced. According to such a configuration, for example, when trying to increase the output of the solar cell module as much as possible, the voltage between the output terminals may be adjusted so that the output power is maximized while the duty ratio of the cutoff remains fixed. It will be. In this case, as already mentioned, it may be difficult to generate electricity at each maximum power point of all solar cells due to the difference in the amount of light received, but the difference in the amount of light received causes the maximum power point in the solar cell. The difference in the generated voltage is relatively small, so it is expected that the reduction in the generated output will not be so great, but the advantage will be that the adjustment will be performed more quickly than before. It should be understood that similar benefits can be obtained when any power cell other than solar cells is connected and operated in series.

Further, in the above-mentioned apparatus of the present invention, regarding the switching control of the conduction / cutoff state of the switching element or the switching means, the state is set between the two phases of the "first phase" and the "second phase". In the configuration of alternating switching, the duty ratio of interruption may always be 0.5, which is advantageous because the control of the switching means becomes extremely easy. In this regard, in such a configuration, further, according to the configuration provided with the "voltage stabilizing capacitor" as described above, the power generation or operation of each solar cell or power cell is performed only by adding a relatively simple configuration. It is advantageous in that the voltage can be stabilized.

Other objects and advantages of the present invention will be apparent from the following description of preferred embodiments of the present invention.

Figure 1 is a characteristic diagram schematically showing a change in the generated current I _R and the generator power P _R for the power generation voltage of the solar cell which has received the various received light amount R. R indicates the ratio of each received light amount, assuming that the received light amount when R = 100% is 100%. FIG. 2 is a circuit configuration diagram showing an embodiment of a configuration of a photovoltaic power generation device according to the present invention. FIG. 2A shows an example in which solar cells are connected to all stages of the multi-stage buck-boost chopper circuit, and FIG. 2B shows one stage of the multi-stage buck-boost chopper circuit. This is an example in which a solar cell is not connected (an example in which an additional capacitor and a switching element are provided). FIG. 3 is a diagram showing an exemplary time chart of an ON / OFF state of a switching element that can be adopted in the circuit configurations of FIGS. 2A and 2B. FIG. 3A shows a case where the switching elements are turned off at different times (when the switching elements are turned off one by one at one time), and FIG. 3B shows the switching elements being turned off. When a part of the time of being put into the state overlaps (the sum of the time lengths of interruptions for all the switching elements in one cycle is made larger than the time length of one cycle, and the parts of the cutoff times are part of each other. (When overlapping between adjacent cutoffs), FIG. 3C shows that two adjacent switching elements are turned off at the same time, and the switching elements that are turned off are from one end to the other. This is the case of shifting one by one to the end of. 4 (A) and 4 (B) are circuit configuration diagrams schematically showing the current flow when the ON / OFF state of the switching element is controlled by the time chart of FIG. 3 (C). The right side of FIG. 5A is an example of a time chart of the ON / OFF state of the switching element that can be adopted in various embodiments of the circuit configuration of the apparatus of the present invention, and the ON / OFF state of the switching element sequence is shown. , An example of switching between phase 1 (Ph1) and phase 2 (Ph2) is shown. The left side of FIG. 5A shows an example of a combination of a switching element group that is turned off in phase 1 and a switching element group that is turned off in phase 2 in the circuit configurations shown in FIGS. 2, 6, 8, and the like. Shown. 5 (B) and 5 (C) are even numbers counted from one of the rows of switching elements connected in series in phase 1 in the ON / OFF state of the switching element train of the apparatus of the present invention, respectively. The state of the circuit in the case where all the switching elements connected in the third state are in the OFF state and all the switching elements connected in the even number are in the ON state, and the switching elements connected in series in phase 2 The state of the circuit when all the switching elements connected in the odd number from one of the rows are turned on and all the switching elements connected in the even number are turned off is schematically shown. ing. FIG. 6A is a circuit diagram showing still another embodiment of the configuration of the photovoltaic power generation device according to the present invention, in which a plurality of solar cell cells connected between output terminals are divided into a plurality of units. , A power generation operating point control circuit device is individually provided for each of these plurality of units, and each power generation operating point control circuit device controls switching of the ON / OFF state of the switching element belonging to the unit. .. FIG. 6B is a circuit diagram showing still another basic embodiment of the configuration of the photovoltaic power generation device according to the present invention, in which a plurality of solar cells connected between output terminals are at boundaries. It is divided into a plurality of units that share one of them with each other, and a power generation operating point control circuit device is individually provided for each of the plurality of units, and each power generation operating point control circuit device is a switching element belonging to the unit. It is designed to control the switching of the ON / OFF state. FIG. 7 is a circuit diagram showing still another embodiment of the configuration of the photovoltaic power generation device according to the present invention, in which output terminals ot + and ot- of a plurality of solar cells connected in series form a voltage control device. It is connected to the load terminals T1 and T2 via. FIG. 8 shows a device (photovoltaic power generation device) formed by combining a solar cell module composed of 2k (k is a positive integer) solar cell cells connected in series according to the present invention and a power generation operating point control circuit device thereof. ), Which is a circuit configuration diagram schematically showing an embodiment provided with a voltage stabilizing capacitor Cvj. 9 (A) shows, in the circuit configuration of FIG. 8, the ON / OFF state of the switching element is phase 1 [the switching element connected in the odd number counting from one of the rows of the switching elements connected in series. When all are in the OFF state and all of the even-numbered switching elements are in the ON state], FIG. 9B shows the voltage stabilization capacitor row at that time. It is a figure which showed the connection state. 9 (C) shows, in the circuit configuration of FIG. 8, the ON / OFF state of the switching element is phase 2 [the switching element connected in the odd number counting from one of the rows of the switching elements connected in series. When all are in the ON state and all of the even-numbered switching elements are in the OFF state], FIG. 9 (D) shows the voltage stabilization capacitor row at that time. It is a figure which showed the connection state. FIG. 10A shows a device formed by combining a solar cell module composed of 2k-1 solar cells (k is a positive integer) connected in series according to the present invention and a power generation operating point control circuit device thereof. It is a circuit block diagram which shows typically the embodiment which is (solar power generation apparatus) and is provided with a voltage stabilization capacitor Cvj. FIG. 10B is a diagram showing a connection state of the voltage stabilizing capacitor train when the ON / OFF state of the switching element is in phase 1 in the circuit configuration of FIG. 10A. FIG. 10 (C) is a diagram showing a connection state of the voltage stabilization capacitor train when the ON / OFF state of the switching element is in phase 2. FIG. 11 shows the present invention in which a 2k-stage (even-numbered) buck-boost chopper circuit provided with a voltage stabilizing capacitor Cvj is connected to a solar cell module composed of 2k-1 (odd-numbered) solar cells. An example of the circuit configuration of the embodiment of the device is shown. FIG. 11A shows a configuration in which an additional capacitor C2k and an additional switching element M2k are connected between the output terminals, and FIG. 11B shows an additional capacitor C2k and an additional switching element outside between the output terminals. It is a configuration in which M2k is connected. 12 (A) to 12 (C) are diagrams showing other circuit configuration examples of the embodiment of the apparatus according to the present invention provided with the voltage stabilizing capacitor Cvj. FIG. 13 is a circuit configuration diagram in a case where an operating point control circuit device according to the present invention provided with a voltage stabilizing capacitor Cvj is replaced with a solar cell and an arbitrary other power supply cell is connected in series. ..

PVj ... Solar cell (j is a positive integer; the same applies hereinafter)
Mj ... Switching element (MOSFET)
Cj ... Capacitor Lj ... Inductor Sj ... Control input ct ... Electrode connection terminal Cvj ... Voltage stabilization capacitor CP ... Switching element switching control device

Some preferred embodiments of the present invention will be described in detail below with reference to the accompanying figures. In the figure, the same reference numerals indicate the same parts.

Basic configuration of power generation operating point control circuit device The circuit configuration of the power generation operating point control circuit device of the solar cell in the photovoltaic power generation device according to the embodiment of the present invention is basically described in Non-Patent Documents 1 to 3. It is the same as the configuration of the multi-stage buck-boost chopper circuit. Specifically, first, referring to FIG. 2A, n (n is a positive integer; 4 in the figure) solar cells PV1, PV2, ..., PVj, ..., PVn are connected in series. When the solar cell module is configured by connecting to, for each of the plurality of solar cell cells PVj connected in series between the pair of output terminals ot + and ot- at both ends of the solar cell module. , The capacitor Cj (C1, C2, ... Cn) and the switching element Mj (M1, M2, ... Mn) are connected in parallel via the connection terminal ct for the electrode, and are connected to each electrode terminal ct of the solar cell PVj. Capacitors Lj (L1, L2 ... L _n-1 ) are respectively inserted between the terminals of the switching element Mj. That is, in the case of the circuit configuration of FIG. 2A, an n-stage chopper circuit is configured by connecting a chopper circuit to each of n solar cells connected in series. Each of the switching elements Mj has a control input Sj, and depending on the input of the control input Sj, both ends of the corresponding solar cell PVj and the capacitor Cj connected in parallel between the upper and lower terminals in the figure, that is, in parallel. It may be a switching means that selectively conducts or cuts off between the terminals of the solar cell, and is typically a switching element such as a MOSFET used in a power generation operating point control circuit device of a normal solar cell. It's okay. Capacitors and inductors can be anything commonly used in the art.

When the power generation operating point control circuit device is actually used, an MPPT control circuit for controlling the voltage Vout between the output terminals or any other voltage / current controller between the output terminals ot + and ot- ( (Not shown) is connected, and the voltage / current controller holds the output voltage between the output terminals at the required voltage or the desired voltage, while the switching controller CP controls the switching element Mj at the control input Sj (S1). , S2 ... Sn), and the switching element Mj conducts between the terminals at both ends of the corresponding solar cell PVj and capacitor Cj connected in parallel, respectively, in a manner described in detail later. It is periodically switched between an ON state (conduction state) for causing the conduction to be performed and an OFF state (disconnection state) for interrupting the continuity.

As illustrated in FIG. 2B, the n-stage chopper circuit is formed by connecting a chopper circuit to each of n (three in the figure) solar cell connected in series. _{On the other hand, a capacitor C n + 1} may be added in series with the capacitor train between the solar cell row and the output terminal ot−, and _{a switching element M n + 1} may be added with respect to the switching element train (Patented). Document 1). In other words, an n + 1-stage chopper circuit may be configured, and a solar cell may not be arranged in one of the chopper circuits. The added chopper circuit portion (capacitor C _{n + 1} , switching element M _{n + 1} , inductor Ln) is, as will be described later, in short, the voltage between the output terminals of the generated voltage of the solar cell connected in series. It functions to boost the voltage more than the total. An additional capacitor and a switching element for the boosting function between the output terminals may be inserted in the stage between the solar cells connected in series, or may be provided in a plurality of sets (that is,). , When n solar cells are connected in series, an n + m stage chopper circuit (m may be a positive integer) may be used.

Switching control of switching element of power generation operating point control circuit device In a photovoltaic power generation device including a solar cell module illustrated in FIG. 2 (A) or FIG. 2 (B) and a power generation operating point control circuit device, a switching element The periodic switching between the ON state and the OFF state of Mj may be executed in various modes. In particular, in the present embodiment, the duty ratio of interruption, that is, a predetermined one cycle (cycle). (The length of the period from when switching from the ON state to the OFF state, after switching to the ON state, and when switching to the OFF state again, that is, the length of the period of the OFF state and the length of the ON state. The ratio of the length of the period in which the OFF state is set to (the sum of the lengths of the periods) is uniformly fixed (that is, set to the same value) for all the switching elements Mj. Hereinafter, the "cutoff duty ratio" is simply referred to as the "duty ratio". An example of a specific mode of switching control of the ON / OFF (conduction / cutoff) state of the switching element Mj may be any of the following.

(First aspect) In the first aspect of the ON / OFF state switching control of the switching element Mj, as shown in FIG. 3A, the duty ratios of all the switching elements Mj are equal to each other. The state of each switching element may be controlled so that the time when all the switching elements are turned off is different from each other. That is, in this case, the number of switching elements that are turned off at one time is always one. In this aspect, currents of different sizes can flow through the solar cell (or the capacitor in the unconnected stage) connected to each stage of the n-stage chopper circuit. Therefore, between the generated voltage (or holding voltage of the capacitor) Vj of the solar cell of each stage, the duty ratio Dj, and the voltage Vout between the output terminals,
Vj = Dj · Vout… (1a)
Dj = D ... (1b)
ΣDj = 1 ... (1c)
(The sum is j = 1 to n)
D = 1 / n ... (1d)
After all, the generated voltage (or holding voltage of the capacitor) Vj of each solar cell is
Vj = Vout / n ... (1e)
Will be given by. Therefore, for example, if the voltage Vout between the output terminals is adjusted so that _{Vout / n becomes equal to the generated voltage Vmpp100 at} the maximum power point of the solar cell having the maximum amount of light received, it is illustrated in FIG. As described above, it is possible to realize a state in which the generated voltage of all the solar cells substantially _{matches Vmpp100} , and in that case, as already mentioned, even if there is a decrease in the amount of received light, the individual duty of the solar cells Without adjusting the ratio, the output reduction width due to this can be suppressed to a relatively small size.

By the way, as shown in FIG. 2A, when the solar cells are connected to all of the n-stage buck-boost chopper circuits, the total power generation voltage Vpj of each solar cell is
ΣVpj = n × Vout / n = Vout… (2a)
(In the case of the example of FIG. 2 (A) Vout = ΣVpj = V1 + V2 + V3 + V4)
Therefore, the sum of the generated voltages of the solar cells is the voltage between the output terminals. On the other hand, as shown in FIG. 2B, when there is a stage in which the solar cell is not connected in the n-stage buck-boost chopper circuit, the total generated voltage Vpj of each solar cell is ΣVpj and the sun. Since the sum of the holding voltage Vcj and the sum of the holding voltage Vcj of the capacitor in the stage to which the battery cell is not connected is Vout, it is eventually Vout.
Vout = ΣVpj + ΣVcj ... (2a)
(In the case of the example of FIG. 2 (B),
ΣVpj = V1 + V2 + V3
ΣVcj = V4 [holding voltage of capacitor C4)
Is. )
Vout> ΣVpj… (2b)
Is established. That is, the circuit portion of the stage to which the solar cell is not connected functions to boost the voltage between the output voltages of the solar cell module to be higher than the total generated voltage of the actual solar cell. The circuit portion that performs this boost function is similarly applicable to all of the circuits described below.

(Second aspect) In the second aspect of the ON / OFF state switching control of the switching element Mj, the duty of all the switching elements Mj is as shown in FIGS. 3 (B) and 3 (C). In a state where the ratios are equal to each other, the sum of the time lengths of cutoffs for all switching elements in one cycle is made larger than the time lengths of one cycle, and the cutoff times are such that some of them are adjacent to each other. The state of the switching element may be controlled so that the switching elements are overlapped between the two, or the switching elements that are temporarily turned off (blocked state) are two adjacent switching elements. In this embodiment, the state of the switching element is controlled by switching in which two adjacent switching elements are temporarily turned off and the switching elements in the OFF state are connected in series, as shown in the figure. It may be executed so as to shift one by one from one end of the row of elements to the other end. When the switching elements are turned off one by one as in the first aspect, each switching element needs to be able to withstand the voltage between the output terminals in the OFF state. However, when two switching elements are turned off at one time, the voltage between the output terminals is distributed and applied to the two switching elements turned off, so that the first aspect is made. Compared with the case of, the voltage to be withstood (required withstand voltage) per switching element can be reduced.

In the case of the second aspect of the switching control of the switching element described above, the power generation voltage (or the holding voltage of the capacitor) Vj of each solar cell is determined by the equation (1e) as in the first aspect. Become. That is, in such an embodiment, as illustrated in FIGS. 4A and 4B, when two adjacent switching elements are in the OFF state at the same time, the switching element has a state. In general, there is a parasitic diode that allows current to flow only from the source side to the drain side, and of the two adjacent switching elements, the switching element that has been turned off first is inside the switching element. The parasitic diode will allow the flow of current coming from the inductor connected to its source side. Then, even if the control signal of the switching element is input to the control input so that two adjacent switching elements are turned off at the same time, the number of switching elements that are cut off at one time is substantially always the same. It becomes the same as the state of being one, and thus the generated voltage (or the holding voltage of the capacitor) Vj of each solar cell is also given as in the first aspect. According to this, also, as in the first aspect, when the state control of each switching element is executed so that the times when all the switching elements are turned off are different from each other, the ON / OFF state can be switched. It can be said that it does not have to be as strict.

(Third aspect) In yet another third aspect of the ON / OFF state switching control of the switching element Mj, the switching element Mj is connected in series as shown in the time chart illustrated on the right side of FIG. 5 (A). The plurality of switching elements (including additional switching elements) are divided into the first set (I) and the second set (II), and all the switching elements in the first set are turned off. Phase 1 (Ph1) in which all the switching elements in the second set are in the ON state, and phase 1 in which all the switching elements in the first set are in the ON state and all the switching elements in the second set are in the OFF state. The states of all the switching elements may be switched alternately with 2 (Ph2). The grouping of the switching elements may be arbitrary, and for example, in the case of a circuit configuration including the switching elements M1 to M4 as shown in FIGS. 2A and 2B, it is illustrated on the left side of FIG. 5A. As described above, (M1, M2) and (M3, M4) may be assigned to each of the first set and the second set, and (M1, M3) and (M2, M4) may be assigned to each of the first set and the second set. Further, as illustrated in FIGS. 5 (B) and 5 (C), in the case of a circuit configuration in which n switching elements exist, an odd number is counted from one of the output terminals, for example, the anode side of the solar cell module. The switching element M _2m-1 connected to the chopper circuit of the second stage is assigned to the first group, and the switching element M _2m connected to the chopper circuit of the even th stage is assigned to the second group. May be (m is a positive integer). In the case of such an embodiment, as shown in the time chart on the right side of FIG. 5A, the states of the switching elements alternately become phase 1 (Ph1) and phase 2 (Ph2) during one cycle Ts, while Since the duty ratio is uniformly fixed for all switching elements, the duty ratio D is, after all,
D = 1/2 = 0.5 ... (3)
Will be.

In the case of the third aspect described above, particularly in the case of the configuration in which the switching element M _2m-1 is assigned to the first set and the switching element M _2m is assigned to the second set, the generated voltage of each solar cell. (Or the holding voltage of the capacitor) Vj is determined by the number of stages of the chopper circuit sandwiched between the output terminals (that is, the number of capacitors and switching elements). Specifically, first, each solar cell in the stage where the sum of the generated voltage (or the holding voltage of the capacitor) Vj of each solar cell is equal to the voltage Vout between the output terminals and the switching element is turned off at the same time. From the condition that the generated voltage (or holding voltage of the capacitor) Vj of the above is equal to each other.
ΣVj = Vout ... (4a)
Vj ^I = VI ... (4b)
Vj ^II = VII ... (4c)
Is established. Here, Vj ^I is the generated voltage (or holding voltage of the capacitor) Vj of each solar cell in the first set, and Vj ^II is the generated voltage (or the holding voltage of the capacitor) of each solar cell in the second set. Holding voltage) Vj. VI and VII are voltage values of the generated voltage (or the holding voltage of the capacitor) of the solar cell of the first set and the second set, respectively. Then, when there is a 2k-stage chopper circuit between the output terminals ot + to ot- (k is a positive integer), the number of stages and the phase in which the switching element is turned off in phase 1 (FIG. 5 (B)). Since the number of stages in which the switching element is turned off in the case of 2 (FIG. 5 (C)) is k stages, which is the same number, the number of stages is the same.
Vj ^I = VI = Vj ^II = VII ... (4d)
Is established, and in the end, the generated voltage (or the holding voltage of the capacitor) Vj of each solar cell is all equal to each other.
Vj = Vout / 2k ... (4e)
Will be.

On the other hand, when there is a 2k-1 stage chopper circuit between the output terminals ot + to ot-, the number of stages in which the switching element is turned off in phase 1 (FIG. 5 (B)) is k stages, and the phase is phase 1. In 2 (FIG. 5 (C)), the number of stages in which the switching element is turned off is k-1. By the way, since phase 1 and phase 2 are realized at equal intervals, the generated voltage of each solar cell in the stage (first set) that is turned off in phase 1 when the voltage is in the steady state. The sum of (or the holding voltage of the capacitor) Vj ^{I and the sum of the generated voltage (or the holding voltage of the capacitor) Vj II} of each solar cell in the stage (second set) that is turned off in phase 2 become equal. ,in the end,
Vout = ΣVj ^I + ΣVj ^II … (4f)
ΣVj ^I = kVI = ΣVj ^II = (k-1) VII = Vout / 2 ... (4g)
The relationship will be established. Thus, the generated voltage (or capacitor holding voltage) Vj ^I of the first set of solar cells and the generated voltage (or capacitor holding voltage) Vj ^II of the second set of solar cells are
Vj ^I = Vout / 2k ... (4h)
Vj ^II = Vout / 2 (k-1) ... (4i)
Will be given by. However, when the switching between phase 1 and phase 2 is sufficiently fast (when the capacitance of the capacitor Cj is sufficiently large), the voltage carried by each chopper circuit is made uniform, and eventually,
Vj = Vout / (2k-1)
Will be established.
[More generalized, in the case of a circuit configuration in which the number of stages of the first set is x and the number of stages of the second set is y, Vj ^I and Vj ^II are
Vj ^I = Vout / 2x
Vj ^II = Vout / 2y
Will be given at. However, as the ratio of x to y becomes larger, the deviation of the generated voltage of each solar cell becomes larger, and the advantage that the output decrease width can be suppressed to be small becomes difficult to obtain. ]

As described above, according to the embodiment in which the duty ratios of the plurality of switching elements are equalized and the ON / OFF state is switched between the two states of phase 1 and phase 2, the duty ratio of the switching elements is adjusted. The time and labor required for this is substantially eliminated, which is advantageous in that control can be greatly simplified. Further, as described in the second aspect, since the number of switching elements that are simultaneously turned off is a plurality of (if the number of stages is more than 4, the same time as compared with the second aspect). The number of switching elements that are turned off will be further increased.) The voltage between the output terminals applied to the switching elements that are turned off is distributed to more elements, thereby switching. The withstand voltage required for each element can be advantageously reduced. Then, as in the first aspect, if the voltage Vout between the output terminals is adjusted so that _{Vout / n becomes equal to the generated voltage Vmpp100 at} the maximum power point of the solar cell having the maximum amount of light received. As illustrated in FIG. 1, it is _{possible to realize a state in which the generated voltages of all the solar cells substantially match Vmpp100} , and even if there is a decrease in the amount of received light, the individual duty ratios of the solar cells The output reduction width due to this adjustment can be suppressed to a relatively small size without any adjustment.

Configuration example of divided control of switching of switching element of power generation operating point control circuit device When the number of cells connected in the solar cell module is large, they are divided into several groups and divided into each group for switching. Switching control of the element may be executed. For example, as illustrated in FIG. 6A, a plurality of solar cells connected between output terminals are divided into a plurality of units, and a power generation operating point control circuit device is individually provided for each of the plurality of units. Each power generation operating point control circuit device may be provided in the above to execute switching control of switching elements belonging to the unit. In the illustrated example, the solar cells PV1 to PV8 are divided into a unit of PV1 to PV4 and a unit of PV5 to PV8, and control devices CP1 and CP2 are individually provided for each unit, and each of them is a switching belonging to the unit. It is configured to control the ON / OFF state of the elements M1 to M4 and M5 to M8. Further, as illustrated in FIG. 6 (B), a plurality of solar cells connected between output terminals are divided into a plurality of units that share one of them at a boundary, and the plurality of units are divided into a plurality of units. A power generation operating point control circuit device may be provided separately for each, and each may execute switching control of the switching element belonging to the unit. In the illustrated example, the solar cells PV1 to PV7 are divided into PV1 to PV4 units and PV4 to PV7 units that share PV4 with each other, and control devices CP1 and CP2 are individually provided for each unit, respectively. Controls the ON / OFF state of the switching elements M1 to M4 and M5 to M8 belonging to the unit.

As illustrated in FIGS. 6 (A) and 6 (B) above, in a configuration in which the solar cell module is divided into a plurality of units, the mode of switching control of the state of the switching element in each unit is described above. It may be any of the first aspect to the third aspect of the above. In particular, when the switching control of the state of the switching element is executed according to the third aspect, as illustrated in FIG. 5A, the units of the switching elements M1 to M4 are included in the first set (M1, M2), assign (M3, M4) to the second set, and assign (M5, M6) to the first set and (M7, M8) to the second set for the units of the switching elements M5 to M8. (A control mode in which adjacent switching elements are turned off at the same time). Further, regarding the units of the switching elements M1 to M4, (M1, M3) are assigned to the first set, (M2, M4) are assigned to the second set, and the units of the switching elements M5 to M8 are assigned to the first set (M1, M3). (M5, M7), (M6, M8) may be assigned to the second set (a control mode in which the switching elements are alternately turned off).

According to these configurations, the number of solar cells in each unit is significantly reduced compared to the total number of solar cells, so that the voltage between both ends of each unit is adjusted to any solar cell in each unit. It is possible to search for the optimum way to control the switching of the switching element by adjusting the solar power in a shorter time, and by optimizing the switching control of each unit in this way, the sun It is possible to improve the followability of the optimization control of the entire photovoltaic power generation device to changes in the light irradiation condition.

Control of voltage between output terminals As already mentioned, the voltage between the output terminals of the above solar cell module is the voltage of the MPPT control circuit or the like so that the generated voltage of the solar cell in the solar cell module becomes a desired value. It is regulated and controlled by the current controller. In this regard, in the configuration of the present invention, as described above, the duty ratio of the switching element is uniformly fixed, so that the generated voltage (or the holding voltage of the capacitor) of each solar cell is used. Is adjusted only by the voltage between the output terminals. Then, as described in connection with FIG. 1, when the power generation voltage of the solar cell is to be adjusted to the power generation voltage at the maximum power point of a certain cell (for example, the cell having the maximum light reception amount). Since the duty ratio is uniformly fixed, the voltage between the output terminals is ultimately uniquely determined (the boost width (holding voltage of the capacitor) of the circuit part that performs the boost function is also between the output terminals. Under the conditions where the voltage and duty ratio are determined, they are uniquely determined and cannot be changed.) On the other hand, when the power generation voltage of the solar cell is adjusted to the power generation voltage at the maximum power point of a certain cell, the voltage between the output terminals of the solar cell module (including the case where there is an additional capacitor) is determined. It does not always match the operating voltage of the load to which the power is output, for example, the charger. If the voltage between the output terminals deviates from the operating voltage of the load, the voltage between the output terminals fluctuates, and the power generation voltage of the solar cell is adjusted to the power generation voltage at the maximum power point of a certain cell. It can be difficult to keep it in a good condition. Therefore, when the output of the photovoltaic power generation device of the present invention is sent to the load, as shown schematically in FIG. 7, the output terminals ot + and ot- of the solar cell module use an arbitrary voltage control device. The power may be transmitted after being connected to the output destinations (loads) T1 and T2 and the voltage between the output terminals is further stepped up and down. With such a configuration, in the photovoltaic power generation device, the voltage between the output terminals of the solar cell module is maintained at a voltage suitable for its operation, and the voltage requirement of the load is maintained while the output of the photovoltaic power generation device is maintained in an efficient state. It becomes possible to correspond to.

Application of Voltage Stabilizing Condenser With reference to FIG. 5 again, in a circuit configuration in which n switching elements exist, in particular, the oddth number counting from one of the output terminals, for example, the anode side of the solar cell module. The switching element M2m-1 connected to the chopper circuit of the stage is assigned to the first set, and the switching element M2m connected to the chopper circuit of the even-th stage is assigned to the second set, and the first set is assigned. Phase 1 (Ph1) in which all the switching elements of the first set are turned off and all the switching elements of the second set are turned on, and all the switching elements of the first set are turned on and all the switching elements of the second set are turned on. In the case of a configuration in which the states of all the switching elements are alternately switched between the phase 2 (Ph2) in which all the switching elements are in the OFF state, the switching control of the switching elements is simplified and the operation of the solar power generation device is performed. Since the parameter to be adjusted is only the voltage Vout between the output terminals, it is very useful in that the time and labor for a series of control can be significantly reduced. Regarding such a configuration, in order to further stabilize the generated voltage (or the holding voltage of the capacitor) of each solar cell, as illustrated in FIG. 8, a voltage is applied to a row of switching elements Mj connected in series. A stabilizing capacitor Cvj (Cv1, Cv2, Cv3 ... Cv _2k-1 ) may be connected. In addition, such a capacitor is hereinafter referred to as a "voltage-stabilized capacitor" (for the purpose of distinguishing it from a capacitor connected in parallel with a solar cell).

More specifically, as shown in the figure, a "voltage stabilizing capacitor" is one end of a row of n (n is a positive integer) switching elements connected in series, for example, a solar cell module. 2m-1st (m is all integers from 1 to n / 2) and all the 2mth connected switching element sets (1st and 2nd sets, 3rd) counting from the anode side of And the 4th set, ...) In parallel with each of both ends, and 2i-2nd (i is all integers from 2 to n / 2) and 2i- counting from one of the above. All of the first connected switching element sets (second and third sets, fourth and fifth sets, ...) Are connected in parallel to each of both ends. The voltage stabilizing capacitor may be a capacitor usually used in this field.

As described above, in the switching element sequence, in the configuration in which each switching element Mj is periodically switched between the phase 1 and the phase 2 in which the switching elements Mj are alternately turned off, a "voltage stabilizing capacitor" is used. If not, the conditions of the above equations (4b) and (4c) (the condition that the generated voltage (or the holding voltage of the capacitor) Vj of each solar cell in the stage where the switching element is turned off at the same time are equal to each other). However, there are cases where it becomes unstable depending on the accuracy of the characteristics of the switching element, parasitic resistance, impedance, etc. (voltage is not evenly distributed, etc.), but due to the presence of the voltage stabilizing capacitor, equation (4b), The condition (4c) will be more reliably secured. Although not shown, the "voltage stabilizing capacitor" includes a configuration for dividing the solar cell module as illustrated in FIG. 6 into a plurality of units and a voltage control device as illustrated in FIG. 7. It should be understood that the configuration is also applicable and that such cases also fall within the scope of the present invention.

In the circuit configuration to which the voltage stabilizing capacitor is applied, the generated voltage (or the holding voltage of the capacitor) Vj of each solar cell is specifically determined as follows.

(I) When n = 2k (k is a positive integer), that is, when the number of switching elements existing in the circuit configuration is an even number, the switching elements are schematically drawn in FIG. Between the rows M1 to M2k, voltage stabilizing capacitors Cv _{1 to Cv 2k-1} are connected so as to alternately straddle two adjacent switching elements. During its operation, the state of the switching element is repeatedly switched between phase 1 and phase 2 alternately, periodically and at equal intervals. Here, in phase 1, the odd-th switching element counted from the anode side of the solar cell module is in the OFF state (FIG. 9 (A)), and the voltage stabilizing capacitors Cv _{1 to Cv 2k-1} are shown in FIG. As shown in (B), Cv1 is independently connected between output terminals ot + to ot-, Cv2 to Cv _2k-1 are connected in series to each other in pairs, and capacitors are connected in series in k stages. On the other hand, in Phase 2, the even-th switching element counted from the anode side of the solar cell module is in the OFF state (FIG. 9 (C)), and the voltage stabilizing capacitors Cv _{1 to Cv As shown in FIG. 9D, 2k-1} is paired with Cv1 to Cv 2k-2 at ot + to ot- between output terminals _{, and Cv 2k-1} is alone and in series with each other. A circuit is constructed in which capacitors are connected in series with k stages. _{Then, since the connection states of the voltage stabilizing capacitors Cv 1 to Cv 2k-1} shown in FIGS. 9 (B) and 9 (D) are repeatedly realized, the phase 1 and the phase 2 appear alternately in the steady state. the voltage stabilizing capacitors _{Cv 1 ~Cv 2k-1} of the voltage _{V (C v1) ~V (Cv} 2k-1) are all equal. (More specifically, in phase 1, V (Cv ₂ ) = V (Cv ₃ ), ..., V (Cv _2k-2 ) = V (Cv _2k-1 ), and in phase 2, V (Cv _2). ) = V (Cv ₁ ), ..., V (Cv _2k-2 ) = V (Cv _2k-3 ). Therefore, in the steady state, V (Cv ₁ ) = V (Cv ₂ ) = V (Cv _3). ) = ... = V (Cv _2k-2 ) = V (Cv _2k-1 ).) Further, where the voltage between the output terminals ot + to ot- is adjusted to Vout, the voltage stabilizing capacitor of the k stage Since it will be carried in a series circuit, after all
V (Cv ₁ ) = V (Cv ₂ ) ... = V (Cv _2k-1 ) = Vout / k ... (5a)
The relationship will be established.

By the way, the voltage Uj carried when each switching element is in the OFF state is stably held by the voltage stabilizing capacitor Cvj, as understood with reference to FIGS. 9A and 9C. So
Uj = V (Cv _j ) = Vout / k ... (5b)
[However, U2k = V (Cv _2k-1 )]
The voltage Uj supported when each switching element is in the ON state is
Uj = 0 ... (5c)
Will be. Then, for the generated voltage (or holding voltage of the capacitor) Vj of each solar cell, when the corresponding switching element Mj is in the OFF state,
Vj + Lj ・ ∫ (dI / dt) = Uj = Vout / k… (5d)
(The integration range is 0 to D · Ts when j = 2m-1, and D · Ts to Ts when j = 2m), and the corresponding switching element Mj is in the ON state. When in
Vj + Lj ・ ∫ (dI / dt) = Uj = 0… (5e)
Relationship is established. Here, since D = 1/2, according to (5d) + (5e),
2Vj + Lj ・ ∫ (dI / dt) [Integral range is 0 to Ts] = Vout / k
Then, Lj ・ ∫ (dI / dt) = 0, so in the end
Vj = Vout / 2k ... (5f)
Will be established. Here, it should be understood that the voltage Uj carried when each switching element is in the OFF state is stably held by the corresponding voltage stabilizing capacitor Cvj in the steady state, thereby. The point is that the generated voltage (or the holding voltage of the capacitor) of each solar cell is also determined more stably. That is, it is advantageous in that a larger tolerance is allowed in the characteristics of the switching element.

(Ii) When n = 2k-1, that is, when the number of switching elements existing in the circuit configuration is an odd number, the switching element trains M1 to are schematically drawn in FIG. 10 (A). Between M2k-1, voltage stabilizing capacitors Cv _{1 to Cv 2k-2} are connected so as to alternately straddle two adjacent switching elements. During its operation, the voltage stabilizing capacitors Cv _{1 to Cv 2k-2} constitute a circuit in phase 1 in which the capacitors are connected in series in k stages, as shown in (FIG. 10 (FIG. 10). B)), in phase 2, a circuit in which capacitors are connected in series with k-1 stages is configured (FIG. 10 (C)). Here, the state of the switching element is switched between the phase 1 and the phase 2 alternately, periodically and at equal intervals, as in the case of (i) above, so that the state of the switching element is in a steady state. information, the voltage _V (C v1) of the voltage stabilizing capacitors _{Cv 1 ~Cv 2k-2 ~V (} Cv 2k-2) is expected that all equal, the voltage of the ot + ~ot- between output terminals to Vout It will be adjusted, so after all
V (Cv ₁ ) = V (Cv ₂ ) ... = V (Cv _2k-2 ) = Vout / (k-1 / 2) ... (6a)
The relationship will be established. Similarly, the voltage Uj carried when each switching element is in the OFF state is the same.
Uj = V (Cv _j ) = Vout / (k-1 / 2) ... (6b)
When each switching element is in the ON state, the supported voltage Uj is in any case.
Uj = 0 ... (6c)
Will be. Then, since the ON / OFF state appears evenly in the phase 1 and the phase 2 for the solar cell (or the capacitor) corresponding to each switching element Mj, the power generation voltage of the solar cell is eventually generated. (Or the holding voltage of the capacitor) Vj is
Vj = Vout / (2k-1) ... (6d)
Will be.

In the case of n = 2k-1, the equation (6a) does not hold unless the switching between the phase 1 and the phase 2 is sufficiently fast, and the generated voltage of the solar cell (or the holding voltage of the capacitor). ) Vj may not be uniform. On the other hand, when n = 2k, the condition of the equation (5a) is stably satisfied, and the generated voltage (or the holding voltage of the capacitor) Vj of the solar cell stably satisfies the state of the equation (5f). It becomes. For this reason, in the present embodiment, more preferably, the power generation operating point control circuit device may be configured so that the number of stages of the buck-boost chopper circuit is an even number. For example, when the number of solar cells connected in series is an odd number, a chopper circuit (capacitor, inductor, switching element) may be added to configure the circuit so that the number of stages is even. In addition, if a chopper circuit part is added for the purpose of boosting the output voltage across the solar cell module and the number of stages of the chopper circuit is odd, a chopper circuit is further added and the total number of stages is even. The circuit may be configured to be.

Reduction of Output Loss in Switching Elements In the above, in the power generation operating point control circuit device of the present embodiment, between phase 1 and phase 2 in which each switching element Mj of the switching element train is alternately turned off. In the case of the configuration of periodic switching, when the number of steps of the buck-boost chopper circuit is even, the generated voltage (or holding voltage of the capacitor) Vj of the solar cell is more stabilized, so that the buck-boost chopper circuit When the number of stages is odd, it is preferable to add a chopper circuit that does not connect a solar cell to make the number of stages even. In this regard, in the case of a chopper circuit that does not connect a solar cell, when the switching element is in the ON state, all the current that passes through the chopper circuit portion passes through the switching element. For example, as shown in FIG. 11A, when a chopper circuit (C2k, M2k, L2k-1) that does not connect a solar cell is added to ot + to ot- between output terminals, the switching element M2k In the ON state, substantially all of the current Iout flowing between the output terminals passes through the switching element M2k. In this case, since the switching element has a significant parasitic resistance, the passage of the current Iout in the switching element M2k causes an output loss due to the resistance.

Therefore, in the power generation operating point control circuit device of the present embodiment, when a chopper circuit that does not connect a solar cell is further added, as illustrated in FIG. 11B, the output terminals are ot + to ot. It is preferable to add the circuit portion to the outside of −. According to such a configuration, the current Iout flowing between the output terminals does not substantially flow in the added switching element M2k, and the output loss can be avoided by that amount, which is advantageous.

The chopper circuit portion added to the outside of the output terminals ot + to ot− may be configured in various embodiments. For example, when the output terminals ot + to ot- connected to the load are formed at both ends of the solar cell module, the chopper circuit portion added is on the cathode side of the solar cell module as shown in FIG. 11 (B). It may be configured on the anode side of the solar cell module as shown in FIG. 12 (A), or may be configured on both pole sides of the solar cell module as shown in FIG. 12 (B). Further, as shown in FIG. 12C, a chopper circuit (C3, M3, L2) that does not connect a solar cell for boosting the output voltage of the solar cell module has already been added between the output terminals ot + to ot-. If so, a chopper circuit portion (C4, M4, L3) may be further added to the outside of the output terminals ot + to ot−.

Omission of inductor in operating point control circuit (short circuit)
In a series of configurations of the photovoltaic power generation device and / or the power generation operating point control circuit device of the present embodiment, both terminals of the electrode connection terminal ct and the capacitor Cj of the solar cell PVj are switching elements via the inductor Lj. It is connected to Mj. As a part of the buck-boost chopper circuit, the inductor Lj cooperates with the corresponding capacitors Cj and the switching element Mj to generate a counter electromotive force against a change in current when the switching element Mj is switched to the ON / OFF state. Fulfill the function that occurs. In this regard, at least one inductor that generates counter electromotive force needs to be interposed between the switching element Mj in the OFF state and the corresponding capacitor Cj, and is provided on both sides of the switching element Mj. It does not have to exist. That is, in short, in the configuration including the multi-stage chopper circuit of the present embodiment, if the inductors are provided in every other stage instead of all stages, the circuit will operate normally. Further, since the inductor has a larger parasitic resistance than a normal conducting wire (for example, a linear copper wire), the larger the number, the larger the power loss due to the resistance. Thus, the switching element connected to the 2i-2nd (i is all integers from 2 to n / 2) and the 2i-1st, counting from one of the output terminals, for example, the anode side of the solar cell module. _{Inductors (L2, L4, ... L 2k-2} , FIGS. 8 to 13 connected between the connection point between them and the connection point of the capacitor corresponding to the switching element, the reference numerals are shown in parentheses. The inductor) may be replaced with a normal conductor. As a result, the power loss in the circuit can be further reduced. The inductors L2, L4, ... L _2k-2 are omitted and short-circuited, and the inductors L1, L3 ... Are left because it is better not to provide an inductor between both ends of the solar cell module and the output terminal. This is advantageous in terms of efficiency, and in that case, inductors L1, L3 ... Are required (in other words, inductors need to be provided every other stage counting from the output terminals).

Application of the power generation operating point control circuit device according to the present invention to other power source elements The series of configurations of the photovoltaic power generation device and / or the power generation operating point control circuit device according to the present embodiment described above is in addition to the solar cell. , Chemical cell, power storage cell, fuel cell (may be a solid oxide fuel cell), thermoelectric power generation element, generator cell (wind force, hydraulic power, tidal power, as illustrated in FIG. It may be an arbitrary generator by an engine or the like.) It may be applied when connecting arbitrary power cells in series. Even if the optimum operating voltage of each of the power supply cells connected in series is different, if the output decrease due to the deviation of the operating voltage is not so large, the duty ratio is uniformly fixed according to the teaching of the present invention. By using the operating point control circuit device, it is possible to reduce the time and labor required for adjusting the operating voltage without significantly reducing the output. Further, the above-described configuration of the power generation operating point control circuit device according to the present invention may be applied regardless of whether the types of power sources connected in series are the same or different. For example, in an operating point control circuit device having a circuit configuration according to the present invention as illustrated in FIGS. 2, 6, 7, and 8, instead of a solar cell, a chemical cell, a capacitor cell, and a fuel are used. Arbitrary power cells such as a battery cell, a thermoelectric power generation element, and a generator cell may be connected in series, and as illustrated in FIG. 13, different power cells may be used in a state of being connected in series.

Although the above description has been made in connection with the embodiments of the present invention, many modifications and modifications can be easily made by those skilled in the art, and the present invention is limited to the embodiments exemplified above. It will be clear that it is not limited and is applied to various devices without departing from the concept of the present invention.

Claims (20)

In a photovoltaic power generation device, a plurality of solar cells or a plurality of solar cells and a capacitor are connected in series between output terminals, and each solar cell or each solar cell and a capacitor are connected between the output terminals. On the other hand, the output terminal receives current from the corresponding solar cell or capacitor by periodically shutting off each of the switching elements by a power generation operating point control circuit device in which the switching elements are connected in parallel via an inductor. As a photovoltaic power generation device to be transmitted to the space, the power generation operating point control circuit device is used for one cycle in which the switching element corresponding to all of the plurality of solar cells or the plurality of solar cells and the capacitor is cut off. Is a device that is designed to fix the cutoff duty ratio for all switching elements. The device according to claim 1, wherein the cutoff times for all the switching elements in the one cycle do not overlap with each other. In the apparatus of claim 1, the sum of the time lengths of interruptions for all the switching elements in the one cycle is made larger than the time lengths of the one cycle, and some of the interruption times are adjacent to each other. A device that overlaps between shutoffs. The apparatus according to claim 1, wherein a plurality of interruptions among the interruptions for all the switching elements in the one cycle are at the same time. In the device according to any one of claims 1 to 4, the plurality of solar cell cells or the plurality of solar cell cells and a capacitor are divided into a plurality of units, and the power generation operating point control circuit device is each of the plurality of units. A device that is individually provided with respect to the unit and controls the interruption of the switching element belonging to the unit. In the device according to any one of claims 1 to 4, the plurality of solar cells or the plurality of solar cells and a capacitor are divided into a plurality of units that share one of them at a boundary, and the power generation operation is performed. A point control circuit device is individually provided for each of these plurality of units, and each device controls the interruption of the switching element belonging to the unit. A device according to any one of claims 1 to 6, wherein the plurality of solar cells or the plurality of solar cells and a capacitor are connected in series between the output terminals via a voltage control device. An operating point control circuit device for multiple power cells connected in series.
A pair of output terminals and
A plurality of electrode connection terminals connected to each electrode terminal of a plurality of power cells connected in series between the pair of output terminals, and a plurality of electrode connection terminals.
A capacitor connected in parallel between the pair of output terminals via the corresponding electrode connection terminal for each of the plurality of power cells.
The pair of output terminals are connected in parallel to each of the plurality of power cells via the corresponding electrode connection terminals and inductors, and the connected pair of electrode connections. Switching means that selectively conducts each other between the terminals,
Each state of the switching means is a conduction state in which the conduction between the pair of electrode connection terminals or both terminals connected between the pair of terminals of the capacitor are conducted, and a cutoff in which the continuity between the two terminals is cut off. Includes control means that alternates between states and at the same predetermined period.
The control means always controls at least a part of the switching means to be in the cutoff state and the other switching means to be in the conduction state, and the cutoff for all the predetermined period lengths of the switching means. A device that is uniformly fixed so that the ratio of the lengths of the periods in which it is in a state is the same as each other. The device according to claim 8, further, between the pair of output terminals, one of the electrode connection terminal and one of the output terminals on one end side of the plurality of power cells connected in series. An additional capacitor is connected in series with the capacitor between the two electrode connection terminals between two power cells adjacent to each other or between two adjacent power cells among the plurality of power cells connected in series. A device in which additional switching means are connected in parallel with the additional capacitor and in series with the switching means. In the apparatus of claim 8 or 9, an additional capacitor is connected in series with the capacitor connected in series between the pair of output terminals and in parallel with the additional capacitor. A device in which an additional switching means is connected in series with the switching means connected in series between the pair of output terminals. A device according to any one of claims 8 to 10, wherein the state of the switching means is controlled by the control means so that the timing of the cutoff state of all the switching means is different from each other. A device according to any one of claims 8 to 10, wherein the state of the switching means is controlled by the control means so that the switching means that is temporarily in the cutoff state is two adjacent switching means. In the device according to any one of claims 8 to 10, among the switching means, the switching means that is temporarily in the cut-off state by the control means is two adjacent switching means and is in the cut-off state. A device in which the state of the switching means is controlled so that the switching means are sequentially shifted one by one from one end of the row of the switching means connected in series to the other end. In any of the devices of claims 8 to 10, all of the switching means connected by the control means at an odd number counting from one of the rows of the switching means connected in series are in the cutoff state. The first phase in which all of the switching means connected to the even number from the one in the row of the switching means are connected to the conduction state, and the first phase connected to the odd number from the one in the row of the switching means. The switching means is connected in series with a second phase in which the switching means is brought into a conductive state and the switching means connected in an even number from one of the rows of the switching means is in a cutoff state. A device in which the states of the switching means are alternately switched. The device according to claim 14, which is the 2m-1st (m is 1 to n /) from one of the n rows of switching means connected in series (n is a positive integer). A voltage stabilizing capacitor is connected in parallel to each of all ends of the switching means set connected to the 2mth (all integers up to 2), and the 2i-2nd (i is) counted from the one. A device in which a voltage stabilizing capacitor is connected in parallel to each of all ends of the set of switching means connected to the 2i-1st (all integers from 2 to n / 2). A device according to any one of claims 8 to 15, wherein a plurality of the switching means are divided into a plurality of groups, and the state of the switching means belonging to each of the plurality of groups is separately controlled for each group. .. In the apparatus of claim 16, at least one power cell is used for both one switching means in the first group and one switching means in the second group between the pair of output terminals. Devices that are connected in parallel. A device according to any one of claims 8 to 17, wherein the pair of output terminals is connected to an output voltage control means for controlling an output voltage between the output terminals. The device according to any one of claims 8 to 18, in the row of n (n is a positive integer) of the switching means connected in series, the 2m-1st (m) counting from one. Is all integers from 1 to n / 2) and the connection point between the switching means connected at the 2mth position and the connection point between the capacitors corresponding to the switching means. With the connection point between the switching means connected via the inductor and connected to the 2i-2nd (i is all integers from 2 to n / 2) and the 2i-1th, counting from the one. A device in which all of the connection points of the capacitors corresponding to the switching means are connected without the inductor. A device according to any one of claims 8 to 19, wherein the power cell is a solar cell, a chemical cell, a fuel cell, a capacitor cell, a generator, a thermoelectric element, and / or a combination thereof.

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