JP3989751B2 - AC stabilized power supply - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an AC stabilized power supply apparatus that constantly supplies a constant voltage AC power supply to a load.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an AC stabilized power supply device (hereinafter referred to as “AVR: Automatic Voltage Regulator”) that compensates for voltage fluctuations of an AC power supply and constantly supplies a constant voltage AC power to a load is known. As this AVR, for example, there is a series compensation type AVR 100 using an inverter shown in FIG.
[0003]
FIG. 4 is a block diagram showing a configuration of a conventional AVR 100. As shown in FIG. According to the figure, the AVR 100 includes a rectifier 2, a power storage device 3, an inverter 4, an inverter controller 50, and an injection transformer 6.
[0004]
The rectifier 2 has an input terminal connected to the AC power source 1 and an output terminal connected to the input terminals of the power storage device 3 and the inverter 4. Then, the AC power supplied from the AC power source 1 is rectified and converted to DC power, and output to the power storage device 3 and the inverter 4.
Further, the rectifier 2 is configured by a bridge by, for example, a diode or a thyristor.
[0005]
The power storage device 3 is connected to the output terminal of the rectifier 2 and the input terminal of the inverter 4. And at the normal time, a DC voltage is applied from the rectifier 2 to charge the battery to a constant voltage. On the other hand, when the level of the output terminal of the rectifier 2 drops below a certain level due to a drop in the supply voltage (hereinafter referred to as “power supply voltage”) of the AC power supply 1, the charged DC power is discharged (discharge). ). The discharged DC power is supplied to the inverter 4.
In addition, the power storage device 3 is configured by, for example, an electric double capacitor, a storage battery, or the like.
[0006]
The inverter 4 has an input end connected to the output end of the rectifier 2 and the output end of the power storage device 3, and an output end connected to the primary side of the injection transformer 6. Further, the main circuit of the inverter 4 is configured by a bridge by a switching element realized by a self-extinguishing power device such as IGBT or GTO.
The inverter 4 converts the DC power input from the power storage device 3 or the rectifying device 2 into AC power in accordance with the PWM control signal input from the inverter control device 50 and outputs the AC power to the primary side of the injection transformer 6. . The output voltage of the inverter 4 is a high-frequency pulse obtained by pulse-width modulating a high-frequency carrier triangular wave with an input DC voltage, that is, a pseudo sine wave.
[0007]
The inverter control device 50 controls the output voltage of the inverter 4 by a sine wave PWM method so as to compensate for the fluctuation of the supply voltage of the AC power supply 1.
That is, the inverter control circuit 50 detects a differential voltage between the power supply voltage and the AC voltage to be supplied to the load, and generates a voltage command signal corresponding to the differential voltage. Then, a high-frequency triangular wave that is a carrier wave is pulse width modulated with the generated voltage command signal, and a PWM control signal for turning on / off the switching element of the inverter 4 is output to the inverter 4 as a gate signal.
[0008]
The injection transformer 6 has a primary side connected to the output terminal of the inverter 4 and a secondary side connected between the AC power source 1 and the load 7. Then, the output power of the inverter 4 is added to the supply power of the AC power supply 1 and supplied to the load 7 (injection of compensation voltage).
[0009]
Therefore, when the power supply voltage fluctuates, the AVR 100 configured as described above causes the inverter 4 to generate AC power corresponding to the fluctuation of the power supply voltage, and supplies this generated power to the load 7 via the injection transformer 6. Thus, the fluctuation of the power supply voltage is compensated, and the load voltage is kept at a constant level.
[0010]
[Problems to be solved by the invention]
However, depending on the load 7, there is an allowable voltage range in which normal operation is guaranteed, for example, within ± 5% of the rated voltage value. That is, if the load voltage is within this allowable voltage range, normal operation of the load 7 is guaranteed.
[0011]
On the other hand, in the series compensation type AVR 100 as shown in FIG. 4, the inverter 4 generates a compensation voltage while following the amount of change in the power supply voltage, thereby achieving a constant voltage. That is, voltage compensation is always performed regardless of whether the load voltage is within the allowable voltage range.
Therefore, voltage compensation is performed within the allowable voltage range, although it is not particularly required. If voltage compensation is not performed in the allowable voltage range, overall efficiency of the entire AVR can be improved and power loss can be reduced.
[0012]
An object of the present invention is to realize voltage compensation in consideration of an allowable voltage range of a load in an AC stabilized power supply (AVR).
[0013]
[Means for Solving the Problems]
  In order to solve the above-mentioned problem, the invention according to claim 1 is characterized in that rectifying means (for example, the rectifying device 2 in FIG. 4) for rectifying AC power supplied from an AC power supply and DC power supplied from the rectifying means. Power storage means (for example, the power storage device 3 in FIG. 4), and an inverter (for example, the inverter 4 in FIG. 4) that converts the DC power discharged from the power storage means into AC power and outputs it, Inverter control means for controlling the inverter to output a compensation voltage corresponding to the voltage fluctuation amount of the AC power supply (for example, the inverter control device 5 in FIG. 4), a supply voltage of the AC power supply, and the compensation voltage In an AC stabilized power supply device (for example, AVR 10 in FIG. 4) including an injection transformer (for example, injection transformer 6 in FIG. 4) that adds in series and supplies the load,
  The inverter control means includes
  A zero-cross circuit (for example, the zero-cross circuit 11 in FIG. 2) that generates a power-phase signal in which the supply voltage of the AC power supply changes in binary level at the zero-cross phase;
  A high-side window comparator (for example, the high-side window comparator 14a in FIG. 2) that compares an upper limit sine wave corresponding to an uncompensated upper limit that is an upper limit of the voltage fluctuation amount and an instantaneous value of the supply voltage of the AC power supply; ,
A low-side window comparator (for example, the low-side window comparator 14b in FIG. 2) that compares a lower limit sine wave corresponding to an uncompensated lower limit that is a lower limit of the voltage fluctuation amount and an instantaneous value of the supply voltage of the AC power supply; ,
  A high-side comparator (for example, the high-side comparator 17a in FIG. 2) that compares a differential voltage value between the upper limit sine wave and the instantaneous value of the supply voltage of the AC power supply and a carrier triangular wave;
A low-side comparator (for example, the low-side comparator 17b in FIG. 2) that compares a differential voltage value between the lower limit sine wave and the instantaneous value of the supply voltage of the AC power supply and a carrier triangular wave;
A logic circuit that controls the inverter based on input signals from the zero-cross circuit, the high-side window comparator, the low-side window comparator, the high-side comparator, and the low-side comparator (for example, the logic circuit 18 in FIG. 2). And comprising
  The logic circuit is:
  It is determined whether the supply voltage of the power supply voltage is within an uncompensated range indicating the voltage fluctuation range of the voltage fluctuation amount, and when the supply voltage of the power supply voltage exceeds the uncompensated upper limit value When the supply of the compensation voltage is subtracted and the supply voltage of the power supply voltage is lower than the uncompensated lower limit, the injection of the compensation voltage is added and the supply voltage of the supply voltage is If it is within the range, the compensation voltage of the inverter is zero-injected.
[0014]
  According to the first aspect of the present invention, when the voltage fluctuation amount of the AC power source is within a predetermined voltage fluctuation range in which normal operation of the load is guaranteed, injection of compensation voltage (stabilization of the load voltage) is performed. The compensation voltage can be injected only when it is outside the predetermined voltage fluctuation range.
  Therefore, especially in the voltage fluctuation range that does not require load voltage compensation.,High efficiency of the device can be realized, and power supply loss from the AC power source to the load can be reduced.
  Furthermore, since voltage compensation is performed for the amount of change in the instantaneous value of the AC power supply voltage, when the voltage fluctuation amount falls outside the predetermined voltage fluctuation range, the inverter is immediately supplied with a compensation voltage. The amount of fluctuation can be compensated for and the load voltage can be stabilized.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments suitable for the invention will be described in detail with reference to the drawings. In the following description, the same elements as those described in the above prior art are denoted by the same reference numerals, and detailed description thereof is omitted.
[0016]
The configuration of the AVR 10 according to the present embodiment is substantially the same as that of the conventional AVR 100, and only the inverter control device 5 is different. Therefore, below, it demonstrates focusing on a structure and operation | movement of the inverter control apparatus 5. FIG.
[0017]
The inverter control device 5 detects the supply voltage of the AC power supply 1, that is, the power supply voltage, controls the output voltage (compensation voltage) of the inverter 4 according to the detected power supply voltage, and the load voltage is as shown in FIG. Adjust to.
[0018]
FIG. 1 is a diagram showing the relationship between the power supply voltage and the load voltage, and the horizontal axis represents the power supply voltage V._S, The vertical axis is the load voltage V_LRespectively.
[0019]
In the figure, the rated voltage V of the load 7_LcIs the rated value of the AC voltage to be supplied to the load 7. That is, in the conventional AVR 100, the load voltage is always the rated voltage V_LcThus, the output voltage of the inverter 4 is controlled.
[0020]
Allowable voltage upper limit V of load 7_LaAnd allowable voltage lower limit V_LbAre the upper limit value and the lower limit value of the allowable voltage range of the load 7, for example, the rated voltage V_LcIt is a value determined according to the load 7, such as a value of ± 5%. The allowable voltage range of the load 7 is a voltage range in which normal operation of the load 7 is guaranteed as described above.
[0021]
In addition, AC power supply uncompensated upper limit V_SaAnd uncompensated lower limit V_SbIs the allowable voltage upper limit V of the load 7 when voltage compensation by the inverter 4 is not performed._LaAnd allowable voltage upper limit V_LbPower supply voltage V corresponding to_SIt is. Therefore, this uncompensated lower limit value V_SbNo compensation upper limit V_SaThe voltage range up to (hereinafter referred to as “the AC power supply non-compensation range”) corresponds to the allowable voltage range of the load 7.
[0022]
And the inverter control apparatus 5 is the power supply voltage V_SHowever, the output voltage of the inverter 4 is controlled depending on whether or not the AC power supply 1 is within the uncompensated range.
Specifically, the power supply voltage V_SIs within the uncompensated range, the inverter control device 5 controls the output voltage of the inverter 4 to “zero”. Therefore, only the AC power supplied from the AC power source 1 is supplied to the load 7, and the load voltage has a value substantially proportional to the power source voltage.
[0023]
Also, the power supply voltage is outside the uncompensated range, especially the uncompensated upper limit V_SaIn the case of exceeding, the inverter control device 5 supplies the inverter 4 with the power supply voltage and the uncompensated upper limit value V._SaA compensation voltage corresponding to the difference voltage (excess) is output. At this time, the polarity of the output voltage of the inverter 4 is determined so that subtraction injection is performed with respect to the supply voltage of the AC power supply 1.
Therefore, the compensation voltage corresponding to the difference voltage of the excess is subtracted and injected through the injection transformer 6, and the load voltage is the allowable voltage upper limit value V of the load._LaWill be compensated for.
[0024]
Also, the power supply voltage is outside the uncompensated range, especially the uncompensated lower limit V_SbThe inverter control device 5 supplies the inverter 4 with an uncompensated lower limit V_SbA compensation voltage corresponding to the difference voltage (deficiency) between the power supply voltage and the power supply voltage is output. At this time, the polarity of the output voltage of the inverter 4 is determined so that addition injection is performed with respect to the supply voltage of the AC power supply 1.
Therefore, a compensation voltage corresponding to the above-described insufficient differential voltage is added and injected via the injection transformer 6, and the load voltage is the allowable voltage lower limit value V of the load._SbWill be compensated for.
[0025]
Next, the internal configuration of the inverter control device 5 will be described with reference to FIG.
FIG. 2 is a block diagram showing an internal configuration of the inverter control device 5. According to the figure, the inverter control device 5 includes a zero cross circuit 11, a PLL (Phase Locked Loop) circuit 12, an upper limit sine wave generation circuit 13a, a lower limit sine wave generation circuit 13b, a window comparator 14, and a high side subtractor 15a. , A low-side subtractor 15b, a triangular wave generation circuit 16, a high-side comparator 17a, a low-side comparator 17b, and a logic circuit 18.
[0026]
The zero-cross circuit 11 generates a signal whose output level changes when the input power-supply voltage 31 becomes “zero”, that is, a signal having a power-supply phase whose binary level changes in the zero-cross phase. The data is output to the PLL circuit 12 and the logic circuit 18.
Specifically, when the instantaneous value of the power supply voltage 31 is a positive value, a signal (H signal) whose level is “H”, and when the instantaneous value is a negative value, a signal “L” (L signal). Are output respectively.
[0027]
The PLL circuit 12 is a circuit that matches the phase and frequency of the output from the oscillator provided therein with the signal (reference signal) of the power supply phase input from the zero-cross circuit 11. 1 is output to the upper limit sine wave generation circuit 13a and the lower limit sine wave generation circuit 13b.
[0028]
The upper limit value sine wave generation circuit 13a is synchronized with the input signal from the PLL circuit 12, and the uncompensated upper limit value V of the AC power source 1 of FIG._SaIs generated and output to the high-side subtraction circuit 15a and the high-side window comparator 14a.
[0029]
The lower limit value sine wave generation circuit 13b is synchronized with the input signal from the PLL circuit 12, and the uncompensated lower limit value V of the AC power source 1 of FIG._SbIs generated and output to the low-side subtraction circuit 15b and the low-side window comparator 14b.
[0030]
The window comparator 14 includes a high side window comparator 14a and a low side window comparator 14b.
[0031]
The high-side window comparator 14a compares the instantaneous value of the power supply voltage 31 with the upper limit sine wave 32 input from the upper limit sine wave generation circuit 13a. Then, a binary level signal corresponding to the comparison result is output to the logic circuit 18.
Specifically, the H signal is output when the instantaneous value of the power supply voltage 31 is greater than the upper limit sine wave 32, and the L signal is output when it is smaller.
[0032]
The low-side window comparator 14b compares the instantaneous value of the power supply voltage 31 with the lower limit sine wave 33 input from the lower limit sine wave generation circuit 13b. Then, a binary level signal corresponding to the comparison result is output to the logic circuit 18.
Specifically, the L signal is output when the instantaneous value of the power supply voltage 31 is greater than the lower limit sine wave 33, and the H signal is output when it is smaller.
[0033]
The high side subtraction circuit 15a calculates a differential voltage between the instantaneous value of the power supply voltage 31 and the upper limit sine wave 32, and outputs the instantaneous differential voltage to the high side comparator 17a.
The low-side subtraction circuit 15b calculates a differential voltage between the instantaneous value of the power supply voltage 31 and the lower limit sine wave 33, and outputs the instantaneous differential voltage to the low-side comparator 17b.
[0034]
The triangular wave generation circuit 16 generates a high-frequency triangular wave (carrier triangular wave) 34, which is a carrier wave for PWM control, and outputs it to the high-side comparator 17a and the low-side comparator 17b.
[0035]
The high-side comparator 17a compares the instantaneous differential voltage value input from the high-side subtraction circuit 15a with the carrier triangular wave 34 input from the triangular wave generation circuit 16, and outputs a binary level signal corresponding to the comparison result to the logic level. Output to the circuit 18.
Specifically, the L signal is output when the instantaneous differential voltage value is larger than the carrier triangular wave, and the H signal is output when it is smaller. That is, it generates and outputs a high-frequency pulse signal in which the pulse width is proportional to the instantaneous differential voltage value.
[0036]
The low-side comparator 17b compares the instantaneous differential voltage value input from the low-side subtraction circuit 15b with the carrier triangular wave 34 input from the triangular wave generation circuit 16, and outputs a binary level signal corresponding to the comparison result to the logic level. Output to the circuit 18.
Specifically, the L signal is output when the instantaneous differential voltage value is larger than the carrier triangular wave 34, and the H signal is output when it is smaller. That is, it generates and outputs a high-frequency pulse signal in which the pulse width is proportional to the instantaneous differential voltage value.
[0037]
The logic circuit 18 includes four switching elements (hereinafter simply referred to as “switches”) 4 a to 4 d of the inverter 4 based on input signals from the window comparator 14, the high-side comparator 17 a, the low-side comparator 17 b, and the zero-cross circuit 11. Inverter switch gate signals 35 to 38 to be driven are generated and output.
[0038]
More specifically, the power supply voltage 31 (V_S) Is within the uncompensated range, or the uncompensated upper limit V_SaOr the uncompensated lower limit V_SbIt is judged whether it is below. Further, the positive / negative of the instantaneous value of the power supply voltage 31 is determined based on the input signal from the zero cross circuit 11, and it is determined whether the compensation voltage injection by the inverter 4 is addition injection, subtraction injection, or zero injection.
[0039]
Then, the determination result and input signals from the high-side comparator 17a and the low-side comparator 17b (the carrier triangular wave 34, the power supply voltage 31 and the uncompensated upper limit value V_SaAnd lower limit V_SbInverter switch gate signals 35 to 38 for turning on / off the switches 4a to 4d of the inverter 4 are generated.
[0040]
Next, operation | movement of the inverter control apparatus 5 is demonstrated using FIG.
FIG. 3 is a time chart for explaining the operation of the inverter control device 5. In the figure, (a) shows the relationship between the power supply voltage 31, the upper limit sine wave 32, and the lower limit sine wave 33, (b) shows the carrier triangular wave 34, and (c) through (f) show the inverter switch gate signal 35. -38, the horizontal axis represents time, and the vertical axis represents voltage.
[0041]
In the figure, (1) indicates the power supply voltage 31 (V_S) Is within the uncompensated range. The instantaneous value of the power supply voltage 31 is a positive value.
[0042]
In this case, in the inverter control device 5, the high side window comparator 14 a outputs to the logic circuit 18 a comparison result that indicates that the instantaneous value of the power supply voltage 31 is smaller than the upper limit sine wave 32.
The low-side window comparator 14 b outputs to the logic circuit 18 a comparison result that indicates that the instantaneous value of the power supply voltage 31 is greater than the lower limit sine wave 33, that is, the L signal.
[0043]
The high side subtraction circuit 15a calculates a differential voltage between the instantaneous value of the power supply voltage 31 and the upper limit sine wave 32, and outputs it to the high side comparator 17a.
The low-side subtraction circuit 15b calculates a differential voltage between the instantaneous value of the power supply voltage 31 and the lower limit sine wave 33, and outputs it to the low-side comparator 17b.
The zero-cross circuit 11 outputs a signal indicating that the instantaneous value of the power supply voltage 31 is a positive value, that is, an H signal, to the PLL circuit 12 and the logic circuit 18.
[0044]
The high-side comparator 17a compares the instantaneous differential voltage input from the high-side subtraction circuit 15a with the carrier triangular wave 34 input from the triangular wave generation circuit 16, and changes the pulse width according to the instantaneous differential voltage. The generated pulse signal is output to the logic circuit 18.
The low-side comparator 17b compares the instantaneous differential voltage input from the low-side subtraction circuit 15b with the carrier triangular wave 34 input from the triangular wave generation circuit 16, and changes the pulse width according to the instantaneous differential voltage. The generated pulse signal is output to the logic circuit 18.
[0045]
The logic circuit 18 determines that the value of the power supply voltage 31 is a positive value from the H signal input from the zero cross circuit 11, and from the L signal input from the high side window comparator 14a and the low side window comparator 14b. The power supply voltage 31 is determined to be within the uncompensated range of the AC power supply 1.
Then, inverter switch gate signals 35 to 38 are generated and output with the switches 4a and 4c turned off and the switches 4b and 4d turned on.
Accordingly, the output voltage of the inverter 4 is “zero”, and the injection of the compensation voltage with respect to the power supply voltage 31 is zero injection.
[0046]
In the figure, (2) indicates the power supply voltage 31 (V_S) Is the uncompensated lower limit V_SbThe case where it is less than is shown. Note that the instantaneous value of the power supply voltage 31 is a negative value.
[0047]
In this case, in the inverter control device 5, the high-side window comparator 14 a outputs to the logic circuit 18 a comparison result that indicates that the instantaneous value of the power supply voltage 31 is greater than the upper limit sine wave 32.
As a result of comparing the power supply voltage 31 and the lower limit sine wave 33, the low-side window comparator 14 b outputs a comparison result indicating that the instantaneous value of the power supply voltage 31 is greater than the lower limit sine wave 33, that is, the L signal to the logic circuit 18. To do.
[0048]
The high side subtraction circuit 15a calculates a differential voltage between the instantaneous value of the power supply voltage 31 and the upper limit sine wave 32, and outputs it to the high side comparator 17a.
The low side subtraction circuit 15b calculates a differential voltage between the instantaneous value of the power supply voltage 31 and the lower limit sine wave, and outputs it to the low side comparator 17b.
The zero cross circuit 11 outputs a signal indicating that the instantaneous value of the power supply voltage 31 is a negative value, that is, an L signal.
[0049]
The high-side comparator 17a compares the instantaneous differential voltage input from the high-side subtraction circuit 15a with the carrier triangular wave 34 input from the triangular wave generation circuit 16, and changes the pulse width according to the instantaneous differential voltage. The generated pulse signal is output to the logic circuit 18.
The low-side comparator 17b compares the instantaneous differential voltage input from the low-side subtraction circuit 15b with the carrier triangular wave 34 input from the triangular wave generation circuit 16, and changes the pulse width according to the instantaneous differential voltage. The generated pulse signal is output to the logic circuit 18.
[0050]
The logic circuit 18 determines from the L signal input from the zero cross circuit 11 that the instantaneous value of the power supply voltage 31 is a negative value, and from the H signal input from the high side window comparator 14a and the low side window comparator 14b. From the input L signal, the power supply voltage 31 (V_S) Is the uncompensated lower limit V_SbIt is judged that it is below. That is, it is determined that the injection of the compensation voltage is addition injection.
[0051]
Then, in order to match the polarity with the power supply voltage 31, the switches 4a and 4b are turned on according to the pulse signal inputted from the low-side comparator 17b together with the inverter switch gate signals 37 and 38 that turn the switch 4c on and the switch 4d off. Inverter switch gate signals 35 and 36 for controlling ON / OFF of are generated and output.
[0052]
Therefore, the inverter 4 has a power supply voltage 31 (V_S) And the lower limit sine wave 33, that is, the uncompensated lower limit V_SbA compensation voltage corresponding to the difference voltage 42 is output, and this compensation voltage 42 is added and injected via the injection transformer 6.
[0053]
In the figure, (3) indicates the power supply voltage 31 (V_S) Is the uncompensated lower limit V_SbThe case where it is less than is shown. The instantaneous value of the power supply voltage 31 is a positive value.
In this case, the operation of each part in the inverter control device 5 is substantially the same as (2) above.
[0054]
However, since the instantaneous value of the power supply voltage 31 is a positive value, the high-side window comparator 14a gives the comparison result that the instantaneous value of the power supply voltage 31 is smaller than the upper limit sine wave 32, that is, the L signal, The window comparator 14 b outputs a comparison result that indicates that the instantaneous value of the power supply voltage 31 is smaller than the lower limit sine wave 33, that is, an H signal, to the logic circuit 18.
The zero cross circuit 11 outputs a signal indicating that the instantaneous value of the power supply voltage 31 is a positive value, that is, an H signal.
[0055]
Then, the logic circuit 18 determines that the instantaneous value of the power supply voltage 31 is a positive value from the H signal input from the zero cross circuit 11, and the L signal input from the high side window comparator 14a and the low side comparator 17b. From the H signal input from the power supply voltage 31 (V_S) Is the uncompensated lower limit V_SbIt is judged that it is below. That is, it is determined that the injection of the compensation voltage is addition injection.
[0056]
Then, in order to match the polarity with the power supply voltage 31, the switch 4a is turned off and the switch 4d is turned on, together with inverter switch gate signals 37 and 38, and the switch 4a, Inverter switch gate signals 35 and 36 for controlling ON / OFF of 4b are generated and output.
[0057]
Therefore, the inverter 4 has a power supply voltage 31 (V_S) And the lower limit sine wave 33, that is, the uncompensated lower limit V_SbA compensation voltage 43 corresponding to the difference voltage is output, and this compensation voltage 43 is added and injected to the power supply voltage 31 via the injection transformer 6.
[0058]
In the figure, (4) and (5) indicate the power supply voltage 31 (V_S) Is the uncompensated upper limit V_SaIt shows the case that exceeds. (4) shows the case where the instantaneous value of the power supply voltage 31 is negative, and (5) shows the case where it is positive.
Also in these cases, each part in the inverter control device 5 operates substantially the same as the above (1) to (3).
[0059]
That is, when the instantaneous value of the power supply voltage 31 is a negative value (4), the high-side window comparator 14a gives a comparison result, that is, an L signal, that the instantaneous value of the power supply voltage 31 is smaller than the upper limit sine wave 32. Further, the low-side window comparator 14 b outputs a comparison result that indicates that the instantaneous value of the power supply voltage 31 is smaller than the lower limit sine wave 33, that is, an H signal, to the logic circuit 18.
The zero cross circuit 11 outputs a signal indicating that the instantaneous value of the power supply voltage 31 is a negative value, that is, an L signal.
[0060]
Then, the logic circuit 18 determines that the instantaneous value of the power supply voltage 31 is a negative value from the L signal input from the zero-cross circuit 11, and the L signal input from the high side window comparator 14a and the low side window comparator. From the H signal input from 14b, the power supply voltage 31 (V_S) Is the uncompensated upper limit V_SaIt is judged that it is over. That is, it is determined that the compensation voltage is injected by subtraction.
[0061]
Then, in order to reverse the polarity with the power supply voltage 31, the switches 4c and 4d are switched according to the pulse signal from the high-side comparator 17a together with the inverter switch gate signals 35 and 36 which turn the switch 4a on and the switch 4b off. Inverter switch gate signals 37 and 38 for controlling ON / OFF of are generated and output.
[0062]
Therefore, the inverter 4 has a power supply voltage 31 (V_S) And the upper limit sine wave 32, that is, the uncompensated upper limit V_SaA compensation voltage 44 corresponding to the difference voltage is output, and this compensation voltage 44 is subtracted and injected into the power supply voltage 31 via the injection transformer 6.
[0063]
When the instantaneous value of the power supply voltage 31 is a positive value (5), the high-side window comparator 14a generates a comparison result, that is, an H signal that the instantaneous value of the power supply voltage 31 is larger than the upper limit sine wave 32. Further, the low-side window comparator 14 b outputs a comparison result that indicates that the instantaneous value of the power supply voltage 31 is larger than the lower limit sine wave 33, that is, an L signal, to the logic circuit 18.
The zero cross circuit 11 outputs a signal indicating that the instantaneous value of the power supply voltage 31 is a positive value, that is, an H signal.
[0064]
Then, the logic circuit 18 determines that the instantaneous value of the power supply voltage 31 is a positive value from the H signal input from the zero-cross circuit 11, and the H signal input from the high side window comparator 14a and the low side window comparator. From the L signal input from 14b, the power supply voltage 31 (V_S) Is the uncompensated upper limit V_SaIt is judged that it is over. That is, it is determined that the compensation voltage is injected by subtraction.
[0065]
Then, in order to reverse the polarity of the power supply voltage 31, the switches 4c and 4d are switched according to the pulse signal from the high-side comparator 17a together with the inverter switch gate signals 35 and 36 for turning off the switch 4a and turning on the switch 4b. Inverter switch gate signals 36 and 37 for controlling ON / OFF of are generated and output.
[0066]
Therefore, the inverter 4 has a power supply voltage 31 (V_S) And the upper limit sine wave 32, that is, the uncompensated upper limit V_SaA compensation voltage 45 corresponding to the difference voltage is output, and this compensation voltage 45 is subtracted and injected into the power supply voltage 31 via the injection transformer 6.
[0067]
In addition, (6) shows the power supply voltage 31 (V_S) Decreases and the non-compensation lower limit V_SbIt shows the case where it falls below. The instantaneous value of the power supply voltage 31 is a negative value.
[0068]
In this case, the power supply voltage 31 (V_S) Is the uncompensated lower limit V_SbThe output of the low-side window comparator 14b changes from an H signal to an L signal when the instantaneous value of the power supply voltage 31 becomes larger than the lower limit sine wave 33.
[0069]
When the output signal of the low-side window comparator 14b changes, the logic circuit 18 changes the power supply voltage 31 to the uncompensated lower limit value V._SbAnd the inverter switch gate signals 37 and 38 for turning the switch 4c on and the switch 4d off as well as the above (2), and in accordance with the pulse signal input from the low-side comparator 17b, Inverter switch gate signals 35 and 36 for controlling ON / OFF of 4a and 4b are generated and output.
[0070]
Therefore, the inverter 4 has a power supply voltage 31 (V_S) And the lower limit sine wave 33, that is, the uncompensated lower limit V_SbA compensation voltage 46 corresponding to the difference voltage is output, and this compensation voltage 46 is added and injected to the power supply voltage 31 via the injection transformer 6.
[0071]
(7) shows the power supply voltage 31 (V_S) Rises and the uncompensated upper limit V_SaIt shows the case that exceeds. The instantaneous value of the power supply voltage 31 is a positive value.
[0072]
In this case, the power supply voltage 31 (V_S) Is the uncompensated upper limit V_SaAt the time when the power supply voltage 31 exceeds the upper limit sine wave 32, the output of the high-side window comparator 14a changes from the L signal to the H signal.
[0073]
Then, when the output signal of the high side window comparator 14a changes, the logic circuit 18 supplies the power supply voltage 31 (V_S) Is the uncompensated upper limit V_SaIn the same manner as in (5) above, the switch 34a is turned OFF and the switch 4b is turned ON, together with inverter switch gate signals 35 and 36, and in accordance with the pulse signal input from the high-side comparator 17a, the switch Inverter switch gate signals 37 and 38 for controlling ON / OFF of 4c and 4d are generated and output.
[0074]
Therefore, the inverter 4 has a power supply voltage 31 (V_S) And the upper limit sine wave 32, that is, the uncompensated upper limit V_SaA compensation voltage 47 corresponding to the difference voltage is output, and this compensation voltage 47 is added and injected to the power supply voltage 31 via the injection transformer 6.
[0075]
With the above configuration, when the power supply voltage is within the allowable voltage range in which the normal operation of the load 7 is guaranteed, the compensation voltage is not injected (load voltage stabilization), and the allowable voltage The compensation voltage can be injected only when it is out of range. Therefore, in a permissible voltage range that does not require load voltage compensation, it is possible to achieve higher efficiency of the device and to reduce power supply loss from the AC power source 1 to the load 7 compared to the case where voltage compensation is not performed. it can.
[0076]
Further, since the instantaneous value of the power supply voltage 31 is compared with the upper limit sine wave 32 and the lower limit sine wave 33, when the power supply voltage 31 fluctuates and falls outside the uncompensated range, the inverter is immediately 4 can generate a compensation voltage to compensate for fluctuations in the power supply voltage 32, and the load voltage can be reliably stabilized.
[0077]
【The invention's effect】
According to the present invention, voltage compensation in consideration of the allowable voltage range of the load can be realized.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a relationship between a power supply voltage and a load voltage.
FIG. 2 is a diagram showing an internal configuration of an inverter control device.
FIG. 3 is a time chart showing the operation of the inverter control device.
FIG. 4 is a diagram showing an internal configuration of a conventional series compensation type AVR.
[Explanation of symbols]
1 AC power supply
10, 100 AC stabilized power supply (AVR)
2 Rectifier
3 Power storage device
4 Inverter
4a to 4d Switching element (switch)
5, 50 Inverter control device
11 Zero cross circuit
12 PLL circuit
13a Upper limit value sine wave generation circuit
13b Lower limit sine wave generation circuit
14 Window comparator
14a High side window comparator
14b Low side window comparator
15a High side subtraction circuit
15b Low side subtraction circuit
16 Triangular wave generator
17a High side comparator
17b Low side comparator
18 logic circuits
6 Injection transformer
7 Load
31 Supply voltage of AC power supply (power supply voltage)
32 Upper limit sine wave
33 Lower limit sine wave
34 Carrier triangle wave
35-38 Inverter switch gate signal

Claims (1)

Rectifying means for rectifying AC power supplied from an AC power supply, power storage means for storing DC power supplied from the rectifying means, and converting DC power discharged from the power storage means into AC power for output An inverter for controlling the inverter to output a compensation voltage corresponding to the voltage fluctuation amount of the AC power supply, and adding the supply voltage of the AC power supply and the compensation voltage in series to the load In an AC stabilized power supply device comprising an injection transformer to supply,
The inverter control means includes
A zero cross circuit that generates a power phase signal in which the supply voltage of the AC power source changes in binary level at the zero cross phase;
A high-side window comparator that compares an upper limit sine wave corresponding to an uncompensated upper limit that is an upper limit of the voltage fluctuation amount and an instantaneous value of a supply voltage of the AC power supply;
A low-side window comparator that compares a lower limit sine wave corresponding to an uncompensated lower limit that is a lower limit of the voltage fluctuation amount and an instantaneous value of the supply voltage of the AC power supply;
A differential voltage value between the upper limit sine wave and the instantaneous value of the supply voltage of the AC power supply, and a high-side comparator that compares a carrier triangular wave;
A differential voltage value between the lower limit sine wave and the instantaneous value of the supply voltage of the AC power supply, and a low-side comparator that compares a carrier triangular wave;
A logic circuit that controls the inverter based on input signals from the zero-cross circuit, the high-side window comparator, the low-side window comparator, the high-side comparator, and the low-side comparator;
The logic circuit is:
It is determined whether the supply voltage of the power supply voltage is within an uncompensated range indicating the voltage fluctuation range of the voltage fluctuation amount, and when the supply voltage of the power supply voltage exceeds the uncompensated upper limit value When the supply of the compensation voltage is subtracted and the supply voltage of the power supply voltage is lower than the uncompensated lower limit, the injection of the compensation voltage is added and the supply voltage of the supply voltage is If it is within the range, the compensation voltage of the inverter is zero-injected.

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