JP5558403B2 - Parallel power supply system - Google Patents

Description

  The present invention relates to a parallel power supply system in which a plurality of power supplies are connected in parallel, and more particularly to a parallel power supply system that supplies power to a load through which a variable current flows.

  Conventionally, a parallel power supply system in which a plurality of power supplies are connected in parallel to increase the capacity of the power supply is known.

For example, Patent Document 1 discloses an assembled battery in which batteries are connected in parallel as a power source for an electric vehicle, a hybrid vehicle, or the like.
However, in the assembled battery as in Patent Document 1, the voltage drop due to the internal resistance of each battery, the wiring resistance of the series battery group, and the like is different for each series battery group, resulting in variations in the current flowing through each series battery group. End up. Therefore, the degree of battery decrease for each series battery group is different, and the variation in the electromotive force of the battery for each series battery group increases with time. If there is variation in the electromotive force of the battery, a return current from the series battery group having a large electromotive force to the series battery group having a small electromotive force may occur. When a return current is generated, an unintended charging / discharging cycle proceeds, so that the battery life is shortened. In addition, power loss becomes a problem due to unintended charging and discharging.

Therefore, it is conceivable to reduce the variation in current of each series battery group by current control using an inverter, a chopper, or the like.
For example, in Patent Document 2, in a circuit device in which a plurality of batteries are connected in parallel, a load current to be borne by each battery is calculated from a measured value of a current flowing through the load, and this and a measured current value flowing through each battery are And a control device that controls the output voltage of a DC-DC converter connected to each battery based on the comparison result. Thereby, the load of the some battery connected in parallel can be equalized.

JP 2002-142353 A JP 2001-095163 A

However, in the control device described in Patent Document 2, a load current to be borne by each battery is calculated from a measured value of the current flowing through the load, and this is compared with a measured current value flowing through each battery. It is necessary to perform complicated control such as adjusting the output voltage of the DC-DC converter based on this. Moreover, since it is necessary to install a current measuring device, a DC-DC converter, etc., equipment cost will be increased. Similarly, when current control is performed using an inverter or a chopper, there is a need for complicated control and equipment costs.
In particular, in the case of a large parallel power supply system (such as a large power storage device) through which a large current flows, the equipment becomes expensive, and it is difficult to introduce this into a large parallel power supply system.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a parallel power supply system capable of smoothing a current flowing through each power supply without performing control with an inexpensive and simple device configuration.

A parallel power supply system according to the present invention is a parallel power supply system that supplies power to a load through which a variable current flows,
A first arm having a first power source and a first inductor connected in series to the first power source;
A second arm connected in parallel with the first arm and having a second power source and a second inductor connected in series to the second power source;
When the current flows from the first arm toward the load, the first inductor and the second inductor generate an electromotive force in a direction in which the output voltage of the second arm is increased in the second inductor. Connected to the
According to the maximum output current ratio or the maximum output power ratio of the first power supply and the second power supply, or when the first power supply and the second power supply are batteries, the first inductor and the power supply The turn ratio with the second inductor is adjusted to a turn ratio other than the same turn number .

In this parallel power supply system, when a current flows from the first arm toward the load, the first inductor and the second inductor are connected so that an electromotive force in the direction of increasing the output voltage of the second arm is generated in the second inductor. Therefore, when current fluctuation occurs in the first arm and the second arm, the current between the arms is smoothed by the mutual induction of the first inductor and the second inductor.
For example, when a current starts to flow through the first arm and the second arm, a case is considered in which a larger amount of current tends to flow through the first arm because the wiring resistance of the first arm is smaller than that of the second arm. In this case, due to the mutual induction of the first inductor and the second inductor, an electromotive force is generated in the first arm against the output voltage of the first power supply, and an electromotive force is generated in the second arm in the same direction as the output voltage of the second power supply. Electric power is generated. Therefore, the current flowing through the first arm and the second arm is equalized (smoothed).
Therefore, the current flowing through each power source can be smoothed without any control by an inexpensive and simple device configuration in which an inductor is provided in each arm. Also, by smoothing (equalizing) the current flowing through each arm, the sum of the power loss (= (current) ² × (resistance)) in the resistance component (internal resistance or wiring resistance of each power supply) in each arm is calculated. Since it can be reduced, the overall power loss can be reduced.

  The parallel power supply system includes an inductor provided between a connection point of the first arm and the second arm and the load, and one end connected between the inductor and the load. A third arm having a third inductor connected in series to three power sources, and the inductor and the third inductor have a current flowing from the first arm and the second arm toward the load, It may be wired so that an electromotive force in a direction to increase the output voltage of the third arm is generated in the third inductor.

  As a result, the current can be smoothed for the three first to third arms.

  The parallel power supply system further includes a third arm connected in parallel to the first arm and the second arm, and having a third power supply and a pair of third inductors connected in series to the third power supply, One arm includes a pair of the first inductors connected in series to the first power source, and the second arm includes a pair of the second inductors connected in series to the second power source, One of the one inductor and the one of the second inductor has an electromotive force in a direction of increasing the output voltage of the second arm when a current flows from the first arm toward the load. When one of the first inductor and one of the third inductor flows from the first arm toward the load, the output of the third arm is connected to the output of the third arm. An electromotive force in the direction of increasing the pressure is connected so as to act on one of the third inductors, and the other of the second inductors and the other of the third inductors are directed from the second arm toward the load. When the current flows, the electromotive force in the direction of increasing the output voltage of the third arm may be connected so as to act on the other of the third inductor.

  In this way, by providing a pair of inductors in each arm and performing current smoothing by mutual induction with the inductors of the other arms, the number of inductors in each arm becomes equal, and the impedance of each arm can be made uniform. it can.

  In the parallel power supply system, the first power supply and the second power supply may be batteries, and may be primary batteries or secondary batteries.

  As described above, since the parallel power supply system can smooth the current between the arms by mutual induction of the inductors provided in each arm and prevent the generation of the ring current, the first power supply and the second power supply are primary. In the case of a battery, unintended primary battery charging due to ring current can be suppressed. In addition, when the first power source and the second power source are secondary batteries, the life of the secondary battery is extended by preventing the generation of ring current, for example, the maintenance of the secondary battery cannot be performed over a long period of time. A highly reliable parallel power supply system that can be operated even under circumstances can be obtained.

When the first power source and the second power source are secondary batteries, an external power source is connected to the first arm and the second arm instead of the load, and the first power source and the power source are supplied from the external power source. said second power source that are adapted to be charged.
Thereby, when a variable current for charging such as a pulse flows from the external power source, the current flowing through each arm can be equalized.

  In the parallel power supply system, the load through which the variable current flows may be, for example, an inverter, a chopper, or a switching power supply.

According to the present invention, when a current flows from the first arm toward the load, the first inductor and the second inductor are connected so that an electromotive force in the direction of increasing the output voltage of the second arm is generated in the second inductor. Therefore, when current fluctuation occurs in the first arm and the second arm, the current between the arms is smoothed by the mutual induction of the first inductor and the second inductor.
Therefore, the current flowing through each power source can be smoothed without any control by an inexpensive and simple device configuration in which an inductor is provided in each arm.

It is a figure which shows the structural example of the parallel power supply system which concerns on 1st Embodiment (reference invention) . It is a figure which shows the structural example of the parallel power supply system which concerns on 2nd Embodiment. It is a figure which shows the structural example of the parallel power supply system which concerns on 3rd Embodiment. It is a figure which shows the structural example of the parallel power supply system using four arms. It is a figure regarding the calculation performed in order to confirm the current smoothing effect | action of the inductor which concerns on Example 1, (a) is the circuit block diagram made into the object of calculation, (b) shows the calculation result of the time-dependent change of an electric current. It is a graph. It is a figure regarding the calculation performed without providing an inductor for the comparison in Example 1, (a) is a circuit block diagram made into the object of calculation, (b) is a graph which shows the calculation result of the time-dependent change of an electric current. . It is a figure regarding the calculation performed in order to confirm the electric current smoothing effect | action of the inductor which concerns on Example 2, (a) is the circuit block diagram made into the object of calculation, (b) shows the calculation result of the time-dependent change of an electric current. It is a graph. It is a figure regarding the calculation performed without providing an inductor for the comparison in Example 2, (a) is a circuit block diagram made into the object of calculation, (b) is a graph which shows the calculation result of the time-dependent change of an electric current. . It is a figure regarding the calculation performed in order to confirm the electric current smoothing effect | action of the inductor which concerns on Example 3, (a) is the circuit block diagram made into the object of calculation, (b) shows the calculation result of the time-dependent change of an electric current. It is a graph. It is a figure regarding the calculation performed without providing an inductor for the comparison in Example 3, (a) is a circuit block diagram made into the object of calculation, (b) is a graph which shows the calculation result of the time-dependent change of an electric current. .

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, and are merely illustrative examples. Only.

[First Embodiment]
FIG. 1 is a diagram illustrating a configuration example of a parallel power supply system according to the first embodiment. As shown in the figure, the parallel power supply system 10 is connected to a load 4 having a switching element 2 and supplies power to the load 4.
The load 4 is a load having the switching element 2 (for example, an inverter, a chopper, a switching power supply, etc.), and can cause a current fluctuation in a short time by the operation of the switching element 2. Here, an example in which the load 4 has the switching element 2 will be described. However, the load 4 may not have the switching element 2 as long as a variable current flows.

The parallel power supply system 10 has a configuration in which a first arm 12 and a second arm 22 are connected in parallel. The first arm 12 includes a first power source 14 and a first inductor 16 connected in series to the first power source 14. Similarly, the second arm 22 includes a second power source 24 and a second inductor 26 connected in series to the second power source 24.
In FIG. 1, reference numerals 18 and 28 denote resistance components such as wiring resistance of each arm (12, 22) and battery internal resistance.

In the present embodiment, the first inductor 16 and the second inductor 26 have an electromotive force in the direction of increasing the output voltage of the second arm 22 when a current flows from the first arm 12 toward the load 4. (In other words, when a current flows from the second arm 22 toward the load 4, an electromotive force is generated in the first inductor 16 in a direction to increase the output voltage of the first arm 12.) Wired to do that).
FIG. 1 shows an example in which the winding start terminals (black circles in FIG. 1) of the first inductor 16 and the second inductor 26 are staggered, but in this example, the first inductor 16 has its winding start terminals. The current flows from the opposite side to the second inductor 26, and the current flows from the winding start terminal side to the second inductor 26. Depending on the connection mode of each inductor (direction of the current flowing through each inductor), the winding start terminal May not be alternate. The point is that when the current flows from the first arm 12 toward the load 4, the first inductor 16 and the second inductor 16 are connected so that the electromotive force in the direction of increasing the output voltage of the second arm 22 acts on the second inductor 26. The inductor 26 is connected.
Further, the first inductor 16 and the second inductor 26 are wound around the common core 20, and the number of turns of both is the same ( the first embodiment in which both the numbers of turns are the same is a reference invention ). .

By connecting the first inductor 16 and the second inductor 26 in this manner, when current fluctuation occurs in the first arm 12 and the second arm 22 due to the operation of the switching element 2, the first inductor 16 and the second inductor 26 The current between the arms is smoothed by mutual induction.
For example, when current starts to flow through the first arm 12 and the second arm 22 due to the operation of the switching element 2, the resistance component 18 of the first arm 12 is smaller than the resistance component 28 of the second arm 22, and thus the first arm Consider the case where more current is going to flow through 12. In this case, due to the mutual induction of the first inductor 16 and the second inductor 26, an electromotive force is generated in the first arm 12 against the output voltage of the first power supply 14, and the output of the second power supply 24 is generated in the second arm 22. An electromotive force is generated in the same direction as the voltage. Therefore, the current flowing through the first arm 12 and the second arm 22 is equalized (smoothed).

  According to the present embodiment, the current flowing through each power source (14, 24) without any control with an inexpensive and simple device configuration in which the inductor (16, 26) is provided in each arm (12, 22). Can be smoothed. Therefore, generation of ring current can be prevented.

  The power source (14, 24) is not particularly limited as long as it is incorporated in the parallel power supply system 10 and can supply power to the load 4. Any power source such as a battery, a large-capacity capacitor (electric double layer capacitor), or a generator can be used. Can be used.

For example, a primary battery or a secondary battery can be used as the power source (14, 24).
As described above, the parallel power supply system 10 can smooth the current between the arms by the mutual induction of the inductors (16, 26) provided in the arms (12, 22), thereby preventing the generation of the ring current. When the power source (14, 24) is a primary battery, unintended charging of the primary battery due to the ring current can be suppressed. Further, when the power source (14, 24) is a secondary battery, the life of the secondary battery can be extended by preventing the generation of ring current. Therefore, for example, the highly reliable parallel power supply system 10 that can be operated even in a situation where the maintenance of the secondary battery cannot be performed over a long period of time can be achieved.

When the power source (14, 24) is a secondary battery, an external power source is connected to the first arm 12 and the second arm 22 instead of the load 4, and the power source (14, 24) is supplied by the power supplied from the external power source. 24) may be charged.
At this time, when a variable current for charging such as a pulse flows from the external power source, the currents flowing through the arms (12, 2) are equalized by mutual induction of the inductors (16, 26).
For example, when the current starts to flow from the external power source to the first arm 12 and the second arm 22, the resistance component 18 of the first arm 12 is smaller than the resistance component 28 of the second arm 22, so Let us consider a case in which a current flows through. In this case, due to mutual induction of the first inductor 16 and the second inductor 26, an electromotive force is generated in the first arm 12 against the charging voltage of the first power source 14, and the second arm 22 is charged by the second power source 24. An electromotive force is generated in the same direction as the voltage. Therefore, the current flowing through the first arm and the second arm is equalized (smoothed).

For reference INVENTION In the present embodiment, the first inductor 16 is the number of turns of the second inductor 26 has been described is the same, the present invention is the ratio of the current flowing through each arm (12, 22) is a predetermined value Thus, the turn ratio of the first inductor and the second inductor is adjusted to a turn ratio other than the same turn number.
For example, the turn ratio of the first inductor 16 and the second inductor 26 is adjusted according to the maximum output current ratio or the maximum output power ratio of each power source (14, 24) . Alternatively, when each power source (14, 24) is a battery, the turn ratio of the first inductor 16 and the second inductor 26 is adjusted according to the capacity ratio of each power source . This makes it possible to apply to power sources (14, 24) having different characteristics (maximum output current ratio, maximum output power ratio, battery capacity ratio, etc.).

[Second Embodiment]
FIG. 2 is a diagram illustrating a configuration example of the parallel power supply system according to the second embodiment. The parallel power supply system 30 shown in the figure is the same as the parallel power supply system 10 of the first embodiment except that current smoothing is performed for three arms. Therefore, the same code | symbol is attached | subjected to the part same as the parallel power supply system 10, and the description is abbreviate | omitted here.

In the parallel power supply system 30, in addition to the first inductor 16 and the second inductor 26 connected in the same manner as in the first embodiment, the inductor is connected between the connection point P 1 of the first arm 12 and the second arm 22 and the load 4. 37 is provided. One end of the third arm 32 is connected between the inductor 37 and the load 4. The third arm 32 includes a third power source 34 and a third inductor 36 connected in series to the third power source 34. The resistance component 38 is a wiring resistance of the third arm 32, a battery internal resistance, or the like.
The inductor 37 and the third inductor 36 have an electromotive force in the direction of increasing the output voltage of the third arm 32 when a current flows from the first arm 12 and the second arm 22 toward the load 4. 36 is connected so as to occur at 36. The inductor 37 is wound around the core 20 common to the third inductor 36, and the number of turns is about half of the number of turns of the third inductor 36. The reason why the number of turns of the inductor 37 is about half that of the third inductor 36 is that the current flowing through the inductor 37 is about twice the current flowing through the third inductor 36.

  In the present embodiment, the current between the first arm 12 and the second arm 22 is smoothed by mutual induction of the first inductor 16 and the second inductor 26. Further, the mutual induction of the inductor 37 and the third inductor 36 smoothes the current after passing through the first arm 12 and the second arm 22 (current flowing through the inductor 37) and the current flowing through the third arm 32. . As a result, variations in current between the arms (12, 22, 32) are suppressed.

In the present embodiment, the example in which the number of turns of the inductor 37 is about half the number of turns of the third inductor 36 has been described. However, the ratio of the current flowing through each arm (12, 22, 32) is set to a predetermined value. The turn ratio between the inductor 37 and the third inductor 36 is set.
For example, the turn ratio between the number of turns of the inductor 37 and the third inductor 36 may be adjusted according to the maximum output current ratio or the maximum output power ratio of each power source (14, 24, 34). Alternatively, if the power supply (14, 24, 34) is battery, according to the capacitance ratio of each power supply, it adjusts the inductor 37 and the turns ratio of the third inductor 36.

[Third Embodiment]
FIG. 3 is a diagram illustrating a configuration example of a parallel power supply system according to the third embodiment. The parallel power supply system 40 shown in the figure is the same as the parallel power supply system 30 of the second embodiment except that the way of connecting the three arms is different. Therefore, the same code | symbol is attached | subjected to the part same as the parallel power supply system 30, and the description is abbreviate | omitted here.

  In the present embodiment, the three arms (12, 22, 32) are connected in parallel, and a power source (14, 24, 34) and a pair of inductors (16A, 16B, 16) connected in series to the power source, respectively. 26A, 26B, 36A, 36B).

The pair of inductors of each arm (12, 22, 32) is provided so as to be able to mutually induct with the inductors of the other arms. Note that the number of turns of the inductors that form a pair so as to cause mutual induction is equal.
Specifically, the first inductor 16A and the second inductor 26A are such that when a current flows from the first arm 12 toward the load 4, the electromotive force in the direction of increasing the output voltage of the second arm 22 is the second inductor. It is wound around a common core 20 so as to occur at 26A. The first inductor 16B and the third inductor 36B generate an electromotive force in the third inductor 36B in a direction to increase the output voltage of the third arm 32 when a current flows from the first arm 12 toward the load 4. It is wound around a common core 20 as shown. Furthermore, the second inductor 26B and the third inductor 36A generate an electromotive force in the third inductor 36A in a direction to increase the output voltage of the third arm 32 when a current flows from the second arm 22 toward the load 4. It is wound around a common core 20 as shown.

In the present embodiment, the current between the first arm 12 and the second arm 22 is smoothed by the mutual induction of the first inductor 16A and the second inductor 26A. Further, the current between the first arm 12 and the third arm 32 is smoothed by the mutual induction of the first inductor 16B and the third inductor 36B. The current between the second arm 22 and the third arm 32 is smoothed by mutual induction of the second inductor 26B and the third inductor 36A. As a result, variations in current between the arms (12, 22, 32) are suppressed.
Moreover, since the number of inductors of each arm (12, 22, 32) is equal, the impedance of each arm can be made uniform.

In the present embodiment, an example in which the number of turns of the inductors that form a pair so as to cause mutual induction is equal to each other has been described. However, the ratio of the currents flowing through the arms (12, 22, 32) is a predetermined value. Then, the turns ratio of the inductors constituting each pair is set to.
For example, the turns ratio of the inductors constituting each pair is adjusted according to the maximum output current ratio or the maximum output power ratio of each power source (14, 24, 34) . Alternatively, the power supply (14, 24, 34) is in the case of batteries, according to the capacitance ratio of each power supply is adjusted to the turns ratio of the inductors constituting each pair.

  As mentioned above, although embodiment of this invention was described in detail, it cannot be overemphasized that this invention is not limited to this, In the range which does not deviate from the summary of this invention, various improvement and deformation | transformation may be performed.

  For example, in the above-described embodiment, the example in which the inductor is provided on the positive terminal side of the power source has been described. However, the inductor may be provided on the negative terminal side of the power source, or the inductor may be provided on both the positive terminal side and the negative terminal side of the power source. Needless to say, it may be provided.

  In the above-described embodiment, an example in which the number of arms is two to three has been described, but the number of arms may be four or more. In this case, the connection manner of the two arms (12, 22) as in the first embodiment, or the connection of the three arms (12, 22, 32) as in the second embodiment or the third embodiment. A parallel power supply system having an arbitrary number of arms may be realized by appropriately combining the modes. For example, in the case of a parallel power supply system using four arms, a plurality of connection modes of the two arms of the first embodiment may be combined.

  FIG. 4 is a diagram illustrating a configuration example of a parallel power supply system using four arms. The parallel power supply system 50 shown in the figure is applied to four arms by combining the connection modes of the first embodiment. Note that the fourth arm 42 includes a fourth inductor 46 connected in series to the fourth power supply 44 as in the other arms. In FIG. 4, the reference numeral 48 indicates a resistance component of the fourth arm 42.

In the parallel power supply system 50, the two arm pairs of the first arm 12, the second arm 22, the third arm 32, and the fourth arm 42 are connected in the same connection manner as in the first embodiment. Specifically, the first inductor 16 of the first arm 12 and the second inductor 26 of the second arm 22 have the output voltage of the second arm 22 when a current flows from the first arm 12 toward the load 4. Is wound around the common core 20 so as to generate an electromotive force in the direction of increasing the second inductor 26. Similarly, the third inductor 36 of the third arm 32 and the fourth inductor 46 of the fourth arm 42 increase the output voltage of the fourth arm 42 when current flows from the third arm 32 toward the load 4. It is wound around the common core 20 so that an electromotive force in the direction is generated in the fourth inductor 46.
Further, an inductor 52 is provided between the connection point P1 of the first arm 12 and the second arm 22 and the load 4, and between the connection point P2 of the third arm 32 and the fourth arm 42 and the load 4. An inductor 54 is provided. When the current flows from the first arm 12 and the second arm 22 toward the load 4, the inductor 52 and the inductor 54 generate an electromotive force in a direction that increases the output voltage of the third arm 32 and the fourth arm 42. It is wound around the common core 20 so as to be generated in the inductor 54.

  Therefore, in the parallel power supply system 50, the arm (by the mutual induction of the first inductor 16 and the second inductor 26, the mutual induction of the third inductor 36 and the fourth inductor 46, and the mutual induction of the inductor 52 and the inductor 54). 12, 22, 32, 42), the variation in current is suppressed.

  In the above-described embodiment, an example in which a pair of inductors (16, 16A, 16B, 26, 26A, 26B, 36, 36A, 36B, 37, 46, 52, 54) is wound around the common core 20 has been described. However, the structure of the core is not particularly limited as long as the paired inductors are connected so as to cause the above-described mutual induction. For example, instead of winding a pair of inductors around a common core 20, there may be only an inductor without a core (air-core), or an inductor may be wound around each of the structurally divided cores (divided cores). Also good.

  The current smoothing action of the inductor of the parallel power supply system according to the above-described embodiment was confirmed by calculation under the following three conditions.

[Example 1]
FIG. 5 is a diagram related to the calculation performed to confirm the current smoothing action of the inductor when there is a difference in the internal resistance of the battery, and FIG. (B) is a graph which shows the calculation result of the time-dependent change of an electric current. 6A and 6B are diagrams relating to the calculation performed without using the inductor for comparison. FIG. 6A is a circuit configuration diagram targeted for the calculation, and FIG. 6B is a calculation result of the change over time of the current. It is a graph to show.

  In the circuit configuration shown in FIG. 5A, the resistances R2 and R3 of the arms (12, 22) are 1.6 mΩ and 2.0 mΩ, respectively. Each arm is provided with inductors (16, 26) wound around a common core. In this circuit configuration, the current flowing through each resistor was calculated. The switching element 2 of the load 4 is repeatedly opened and closed based on the pulse signal output from the PWM control unit 52.

As shown in FIG. 5B, it was found that the difference between the current I _R2 [A] flowing through the resistor R2 of the arm 12 and the current I _R3 [A] flowing through the resistor R3 of the arm 22 was reduced. In FIG. 5B, _IL1 means the magnitude of current flowing through LOAD1.

On the other hand, the circuit configuration shown in FIG. 6A is the same as the circuit configuration shown in FIG. 5A except that an inductor is not provided in each arm. Figure 6 was calculated the current through each resistor in the circuit configuration shown in (a), as shown in FIG. 6 (b), a current flows through the current _I R5 [A] and a resistor R6 through resistor R5 _I R6 [A ] Was larger than that in FIG.

[Example 2]
FIG. 7 is a diagram related to the calculation performed to confirm the current smoothing action of the inductor when balanced (when in equilibrium) when discharging from each battery when there is a difference in the internal resistance of the battery. FIG. 7A is a circuit configuration diagram targeted for calculation, and FIG. 7B is a graph showing a calculation result of a change in current over time. FIG. 8 is a diagram related to a calculation performed without using an inductor for comparison, FIG. 8A is a circuit configuration diagram for calculation, and FIG. 8B is a calculation result of current change over time. It is a graph to show.

In the circuit configuration shown in FIG. 7A, since the internal resistances (R2 and R3) are different, there is a difference in the battery voltages (15.99V and 16.01V) in the equilibrium state. In this circuit configuration, when the current flowing through each resistor is calculated, the current I _R2 [A] flowing through the resistor R2 of the arm 12 and the current I _R3 [A] flowing through the resistor R3 of the arm 22 are calculated as shown in FIG. It was found that the difference from A] was reduced.

On the other hand, the circuit configuration shown in FIG. 8A is the same as the circuit configuration shown in FIG. 7A except that an inductor is not provided in each arm. 8 was calculated the current through each resistor in the circuit configuration shown in (a), as shown in FIG. 8 (b), a current flows through the current _I R5 [A] and a resistor R6 through resistor R5 _I R6 [A ] Was larger than that in FIG. Also, I _R5 flowing through the resistor R5, when the switch S2 is OFF, has a negative current, it was found that the resistance R5 and ring current. Such a ring current was not confirmed in FIG.

[Example 3]
FIG. 9 is a diagram relating to calculations performed to confirm the current smoothing action of the inductor when balanced (when balanced) when charging each battery when there is a difference in the internal resistance of the battery. FIG. 9A is a circuit configuration diagram targeted for calculation, and FIG. 9B is a graph showing a calculation result of a change in current with time. FIG. 10 is a diagram related to a calculation performed without using an inductor for comparison. FIG. 10A is a circuit configuration diagram for calculation, and FIG. 10B is a calculation result of current change over time. It is a graph to show.

In the circuit configuration shown in FIG. 9A, since the internal resistances (R2 and R3) are different, there is a difference in the battery voltages (16.01V and 15.99V) in the equilibrium state. In this circuit configuration, when the current flowing through each resistor is calculated, the current I _R2 [A] flowing through the resistor R2 of the arm 12 and the current I _R3 [A] flowing through the resistor R3 of the arm 22 are calculated as shown in FIG. It was found that the difference from A] was reduced. When switch S1 is OFF, IR2 flowing through _R2 is a negative current, and the generation of ring current was confirmed, but the magnitude of the ring current was relatively small.

On the other hand, the circuit configuration shown in FIG. 10A is the same as the circuit configuration shown in FIG. 9A except that no inductor is provided in each arm. Figure 10 was calculated the current through each resistor in the circuit configuration shown in (a), FIG. 10 (b), the electric currents flowing through R5 _I R5 [A] and the current flowing through the resistor R6 _I R6 [A ] Was larger than that in FIG. Also, I _R5 flowing through the resistor R5, the switch S2 is at OFF, the has a negative current, it was found that a large ring current flows than 9 to resistor R5 (b).

  From the calculation results in Examples 1 to 3, when the internal resistance of the battery varies (Example 1), and when the electromotive force of the battery varies in addition to the variation of the internal resistance of the battery (Example 2) And 3), it was confirmed that the current can be smoothed by using the mutual induction of the inductor.

2 switching element 4 load 10 parallel power supply system 12 1st arm 14 1st power supply 16 1st inductor 18 resistance component 20 core 22 2nd arm 24 2nd power supply 26 2nd inductor 28 resistance component 30 parallel power supply system 32 3rd arm 34 3rd power supply 36 3rd inductor 37 Inductor 38 Resistance component 40 Parallel power supply system 42 4th arm 44 4th power supply 46 4th inductor 48 Resistance component 50 Parallel power supply system 52 Inductor 54 Inductor P1 Connection point P2 Connection point

Claims (9)

A parallel power supply system that supplies power to a load through which a variable current flows,
A first arm having a first power source and a first inductor connected in series to the first power source;
A second arm connected in parallel with the first arm and having a second power source and a second inductor connected in series to the second power source;
When the current flows from the first arm toward the load, the first inductor and the second inductor generate an electromotive force in a direction in which the output voltage of the second arm is increased in the second inductor. Connected to the
According to the maximum output current ratio or the maximum output power ratio of the first power supply and the second power supply, or when the first power supply and the second power supply are batteries, the first inductor and the power supply A parallel power supply system, wherein a turn ratio with the second inductor is adjusted to a turn ratio other than the same turn number . An inductor provided between a connection point of the first arm and the second arm and the load;
A third arm having one end connected between the inductor and the load and having a third power source and a third inductor connected in series to the third power source;
When the current flows from the first arm and the second arm toward the load, the inductor and the third inductor generate an electromotive force in the direction of increasing the output voltage of the third arm in the third inductor. The parallel power supply system according to claim 1, wherein the parallel power supply system is connected in such a manner. A third arm connected in parallel to the first arm and the second arm, and having a third power source and a pair of third inductors connected in series to the third power source;
The first arm has a pair of the first inductors connected in series to the first power source,
The second arm has a pair of the second inductors connected in series to the second power source,
One of the first inductor and the one of the second inductor has an electromotive force in a direction to increase an output voltage of the second arm when a current flows from the first arm toward the load. Is connected to occur on one side of
When the current flows from the first arm toward the load, the other one of the first inductor and the one of the third inductor generates an electromotive force in a direction to increase the output voltage of the third arm. Is connected to occur on one side of
The other of the second inductor and the other of the third inductor has an electromotive force in a direction to increase the output voltage of the third arm when a current flows from the second arm toward the load. The parallel power supply system according to claim 1, wherein the parallel power supply system is connected so as to occur in the other of the two.   The parallel power supply system according to claim 1, wherein the first power supply and the second power supply are batteries.   The parallel power supply system according to claim 4, wherein the battery is a secondary battery.   An external power source is connected to the first arm and the second arm instead of the load, and the first power source and the second power source are charged by electric power supplied from the external power source. 5. The parallel power supply system according to 5.   The turn ratio between the first inductor and the second inductor is set according to one of a maximum output current ratio and a maximum output power ratio between the first power source and the second power source. The parallel power supply system according to claim 1. The first power source and the second power source are batteries,
2. The parallel power supply system according to claim 1, wherein a turn ratio between the first inductor and the second inductor is set in accordance with a capacity ratio between the first power supply and the second power supply. The parallel power supply system according to any one of claims 1 to 8, wherein the load through which the variable current flows is any one of an inverter, a chopper, and a switching power supply.

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