JP2016116404A - Output power control method for ac power supply device, and ac power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that, in a conventional AC power supply device, a ratio of an inverted load flow component of generated power caused by a renewable energy source is small.SOLUTION: One embodiment of an output power method for an AC power supply device is an output power control method for an AC power supply device which operates while being interlocked with a commercial AC power source that supplies a commercial AC signal to system wiring. While controlling storage power Pbat supplied from a power storage part BAT so as to follow load power Ppl to be consumed by a load circuit PL that is connected to the system wiring, a voltage of the storage power Pbat is converted, and a first DC power signal is outputted. The first DC power signal and a second DC power signal supplied from the renewable energy source are combined in DC bus wiring 15 and while controlling power of the AC power signal outputted to the system wiring in such a manner hat a bus voltage Vdc of the DC bus wiring 15 becomes closer to a preset bus voltage command value, DC power transmitted via the DC bus wiring 15 is converted into the AC power signal.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an output power control method and an AC power supply apparatus for an AC power supply apparatus, and more particularly to an output power control method and an AC power supply apparatus for an AC power supply apparatus that can be connected to a commercial power supply.

  2. Description of the Related Art In recent years, an AC power supply device that can transmit renewable energy generated by using a solar battery panel, a windmill, or the like through a system wiring to which commercial power is supplied is widely used. The electric power to be sent is stored in the power storage device, and the power storage device stores the renewable energy and the fossil fuel energy (commercial power) in a mixed state. The power to be transmitted is preferably renewable energy. This is because it is not desirable from the viewpoint of the use of renewable energy to store commercial power and send it again. Therefore, for example, in an AC power supply device that combines a power source using renewable energy and a power storage device such as a storage battery, reverse power flow to the system wiring side of AC power generated based on the power output from the power storage device is prevented. It is demanded. Thus, Patent Document 1 shows an example of an AC power supply device that combines a solar battery and a storage battery.

  In the power storage solar power generation system described in Patent Literature 1, the amount of received power supplied from the system wiring is monitored, and the power storage means prevents the amount of received power from falling below a predetermined level. The amount of power output from the power conversion means for extracting power is controlled.

Japanese Patent No. 4765162

  However, in the technique described in Patent Document 1, although the received power can be reduced, the power stored in the load circuit cannot be supplied by the power that can be supplied by renewable energy among the power consumed by the load circuit. It can only be compensated by the power. That is, the technique described in Patent Document 1 has a problem that the amount of renewable energy that cannot be transmitted is large. Other problems and novel features will become apparent from the description of the specification and the accompanying drawings.

  One aspect of an output power control method for an AC power supply apparatus according to the present invention is an output power control method for an AC power supply apparatus that operates in conjunction with a commercial AC power supply that supplies a commercial AC signal to a system wiring, and is supplied from a power storage unit. The stored power is converted so as to follow the load power consumed by the load circuit connected to the system wiring, the voltage of the stored power is converted, and a first DC power signal is output. The DC power signal of 1 and the second DC power signal supplied from the renewable energy source are combined in the DC bus wiring, and the bus voltage of the DC bus wiring approaches the preset bus voltage command value. The DC power transmitted through the DC bus wiring is converted to the AC power signal while controlling the power of the AC power signal output to the system wiring.

  One aspect of an AC power supply apparatus according to the present invention is an AC power supply apparatus that operates in conjunction with a commercial AC power supply that supplies a commercial AC signal to a system wiring, and converts a voltage of stored power supplied from a power storage unit. A first DC voltage converter for outputting a first DC power signal; a DC bus wiring for combining and transmitting the first DC power signal and a second DC power signal supplied from a renewable energy source; An inverter that outputs an AC power signal obtained by converting DC power transmitted through the DC bus wiring to AC power at a load connection point to which a load circuit is connected in the system wiring; and the first DC power signal And a control unit that controls the first DC voltage converter so as to follow the load power consumed by the load circuit.

  In the output power control method and the AC power supply apparatus according to the present invention, the magnitude of the stored power component supplied from the power storage unit included in the AC power signal output by the inverter follows the power consumption of the load circuit. Change. Thereby, in the power supply device concerning this invention, the power consumption of a load circuit is satisfy | filled with the stored electric power supplied from an electrical storage part, and most of the generated electric power supplied from a renewable energy source can be sent out.

  According to the present invention, only renewable energy can be delivered.

1 is a block diagram of an AC power supply device according to a first exemplary embodiment; FIG. 3 is a block diagram of a converter control unit according to the first embodiment. 1 is a block diagram of an inverter according to a first embodiment; 3 is a timing chart for explaining the operation of the AC power supply device according to the first exemplary embodiment; FIG. 3 is a block diagram for explaining a comparative example of the AC power supply device according to the first exemplary embodiment; It is a timing chart explaining operation | movement of the alternating current power supply apparatus of a comparative example.

Embodiment 1
Embodiments of the present invention will be described below with reference to the drawings. For clarity of explanation, the following description and drawings are omitted and simplified as appropriate. Moreover, in each drawing, the same code | symbol is attached | subjected to the same element and duplication description is abbreviate | omitted as needed.

  FIG. 1 shows a block diagram of an AC power supply apparatus 10 according to the first exemplary embodiment. In FIG. 1, in order to more specifically describe the usage mode of the AC power supply device 10, a commercial AC power supply SPS that is a target for the AC power supply device 10 to be linked and a load circuit that is a power supply target of the AC power supply device 10. The AC power supply system 1 including the solar battery panel PV and the storage battery BAT, which are power sources for the AC power signal output from the PL and the AC power supply apparatus 10, is shown.

  Note that the solar cell panel PV is an aspect of a renewable energy source, and an electric power source such as a wind power generator or a hydroelectric power generator can be used in addition to the solar cell panel PV. In the following description, the power output from the solar cell panel PV is referred to as generated power Ppv. In addition, the storage battery BAT is an aspect of the power storage unit, and a power storage device such as a large-capacity capacitor or a flywheel can be used in addition to the storage battery. In the following description, the power output from the storage battery BAT is referred to as stored power Pbat.

  As shown in FIG. 1, the AC power supply device 10 outputs an AC power signal to the system wiring to which the commercial AC signal is supplied from the commercial AC power supply SPS. A load circuit PL that is a power supply destination is connected to the system wiring. In the following description, a connection point between the system wiring and the load circuit is referred to as a load connection point. Further, the power of the AC power signal output from the AC power supply apparatus 10 to the system wiring is referred to as Pinv, the load power consumed by the load circuit PL is referred to as Ppl, and the reverse flow power to the commercial AC power supply SPS is referred to as Pr.

  As shown in FIG. 1, an AC power supply apparatus 10 includes a second DC voltage converter (for example, a DC / DC converter 11), a first DC voltage converter (for example, a DC / DC converter 12), and an inverter (for example, a DC). / AC inverter 13), a control unit (for example, converter control unit 14), and a DC bus wiring 15.

  The DC / DC converter 11 converts the voltage of the generated power supplied from the solar cell panel PV and outputs a second DC power signal. In the following description, in order to simplify the description, the loss generated in the DC / DC converter 11 is omitted, and the generated power supplied from the solar cell panel PV and the power of the second DC power signal are the same. Think. The DC / DC converter 11 can be omitted depending on the specifications of the solar battery panel PV.

  The DC / DC converter 12 converts the voltage of the stored power supplied from the storage battery BAT and outputs a first DC power signal. In the following description, in order to simplify the description, loss generated in the DC / DC converter 12 is omitted, and the stored power supplied from the storage battery BAT and the power of the first DC power signal are considered to be the same.

  The second DC power signal output from the DC / DC converter 11 and the first DC power signal output from the DC / DC converter 12 are combined by the DC bus wiring 15 and supplied to the DC / AC inverter 13.

  The DC / AC inverter 13 outputs an AC power signal obtained by converting DC power transmitted through the DC bus wiring 15 into AC power at a load connection point to which a load circuit is connected in the system wiring. Further, the DC / AC inverter 13 has a bus voltage control unit. The bus voltage control unit holds a preset bus voltage command value therein, monitors the voltage of the DC bus wiring 15 (hereinafter referred to as bus voltage Vdc), and makes the bus voltage Vdc approach the bus voltage command value. The output capability of the DC / AC inverter 13 is adjusted. That is, the DC / AC inverter 13 controls the DC bus wiring 15 while controlling the power of the AC power signal output to the system wiring so that the bus voltage Vdc of the DC bus wiring 15 approaches a preset bus voltage command value. The DC power transmitted through the converter is converted into an AC power signal. The detailed configuration of the DC / AC inverter 13 will be described later.

  The converter control unit 14 controls the output capability of the DC / DC converter 12 so that the stored power acquired by the stored power monitor unit CS_BAT follows the load power acquired by the load power monitor unit CS_PL. Here, the converter control unit 14 controls the output capability of the DC / DC converter 12 so that the stored power Pbat does not exceed the load power Ppl.

  Here, details of the converter control unit 14 will be described. FIG. 2 is a block diagram of the converter control unit 14 according to the first embodiment. FIG. 2 also shows a detailed block diagram of the DC / DC converter 12 in order to explain the converter control unit 14 in more detail.

  As shown in FIG. 2, the converter control unit 14 includes a load power detection unit 20, an output stored power detection unit 21, and a power control unit 22. Further, the DC / DC converter 12 includes a PWM control unit 23 and a converter unit 24.

  The load power detection unit 20 detects the magnitude of the load power consumed by the load circuit PL based on the load power information obtained from the load power monitor unit CS_PL. For example, the load power information includes system voltage information and load current information. Then, the load power detection unit 20 calculates the load power Ppl by multiplying the system voltage and the load current. Note that the load power Ppl output from the load power detection unit 20 may be multiplied by a coefficient considering an error in the system.

  The output stored power detection unit 21 calculates the stored power Pbat output from the DC / DC converter 12 based on the stored power information obtained from the stored power monitor unit CS_BAT. For example, the storage power information includes a storage unit output voltage that is information on a voltage output from the storage battery BAT and a storage unit output current that is information on a current output from the storage battery BAT. The output stored power detection unit 21 calculates the stored power Pbat by multiplying the storage unit output voltage and the storage unit output current. Note that the stored power Pbat output from the output stored power detection unit 21 may be multiplied by a coefficient that takes into account the loss or the like in the DC / DC converter 12.

  The power control unit 22 amplifies the difference between the load power Ppl and the stored power Pbat, and outputs a control signal corresponding to the difference between the two values to the PWM control unit 23. Then, the PWM control unit 23 adjusts the duty ratio of the PWM signal supplied to the converter unit 24 so that the difference value between the load power Ppl and the stored power Pbat given by the control signal approaches zero. As a result, the stored power Pbat output by the converter unit 24 varies so as to follow the load power Ppl. The power control unit 22 outputs a control signal so that the stored power Pbat is equal to or less than the load power Ppl.

  Next, details of the DC / AC inverter 13 will be described. FIG. 3 shows a block diagram of the DC / AC inverter 13 according to the first embodiment. As shown in FIG. 3, the DC / AC inverter 13 includes a system phase detection unit 30, a bus voltage control unit 31, an inverter power control unit 32, a PWM control unit 33, and an inverter unit 34.

  The system phase detection unit 30 acquires system voltage information from the system signal monitor unit (not shown in FIG. 1), and detects the phase of the commercial AC signal on the system wiring based on the system voltage information. Then, the system phase detection unit 30 outputs the detected phase information of the commercial AC signal to the inverter power control unit 32.

  The bus voltage control unit 31 acquires the bus voltage Vdc of the DC bus wiring 15, and based on the difference value between the bus voltage Vdc and a preset bus voltage command value, the inverter power that instructs increase / decrease of the power of the AC power signal Outputs the command value. This inverter power command value is output to the inverter power control unit 32.

  The inverter power control unit 32 acquires the inverter power measurement value by the output current monitor unit that monitors the output power of the own inverter (not shown in FIG. 1). Then, the inverter power control unit 32 determines whether to increase or decrease the inverter power measurement value based on the inverter power command value, and outputs an inverter control signal based on the determination. Further, the inverter power control unit 32 adjusts the value of the inverter control signal so that the phase of the AC power output from the inverter unit 34 matches the phase of the commercial AC voltage based on the phase information output from the system phase detection unit 30. . The PWM control unit 33 determines the duty ratio of the PWM signal based on the inverter control signal, and outputs the PWM signal to the inverter unit 34. The DC / AC inverter 13 controls the power of the AC power signal so that the bus voltage Vdc is maintained near the bus voltage command value. By performing the above control, the power Pinv of the AC power signal output from the DC / AC inverter 13 is a value obtained by adding the load power Ppl and the generated power Pv.

  The inverter power control unit 32 may generate an inverter control signal based on the inverter power command value without using the inverter power measurement value.

  Next, the operation of the AC power supply device 10 according to the first exemplary embodiment will be described. First, the relationship between the power Pinv of the AC power signal output from the AC power supply apparatus 10 and the power Pr flowing backward to the system power supply SPS side will be described.

In the AC power supply device 10 according to the first exemplary embodiment, the stored power Pbat has the relationship of the expression (1) by the operations of the DC / DC converter 12 and the converter control unit 14.
Pbat = Ppl (1)

Further, in the AC power supply apparatus 10 according to the first exemplary embodiment, the power Pinv of the AC power signal output from the DC / AC inverter 13 has the relationship of the expression (2).
Pinv = Ppv + Pbat (2)
In the AC power supply device 10 according to the first exemplary embodiment, the stored power Pbat corresponding to the load power Ppl is always supplied to the DC bus wiring 15 by the DC / DC converter 13. Further, in the AC power supply device 10 according to the first exemplary embodiment, the generated power Ppv is supplied from the DC / DC converter 11 to the DC bus wiring 15. Therefore, when the bus voltage Vdc is maintained at the bus voltage command value, the DC / AC inverter 13 must output an AC power signal that is the same power as the power supplied to the DC bus wiring 15. In the DC / AC inverter 13, the AC power signal is controlled based on the bus voltage Vdc in order to realize the relationship of the above expression (2).

From the configuration of the AC power supply system 1 shown in FIG. 1, the reverse power flow Pr has a relationship of the expression (3).
Pr = Pinv−Ppl (3)

Then, when the expressions (1) and (2) are substituted into the expression (3), the relationship of the expression (4) can be obtained.
Pr = Ppv (4)
That is, by using the AC power supply device 10 according to the first embodiment, almost all of the generated power Pv can be reversely flowed to the commercial AC power supply SPS side. This operation will be described using a timing chart. FIG. 4 is a timing chart showing the operation of the AC power supply apparatus 10 according to the first embodiment.

  In the example illustrated in FIG. 4, the load power Ppl and the generated power Ppv change with time. As illustrated in FIG. 4, the AC power supply device 10 according to the first embodiment changes the magnitude of the stored power Pbat by following the change in the load power Ppl. Therefore, in the AC power supply device 10, almost all of the generated power Ppv is output to the commercial AC power supply SPS side as the reverse power flow Pr. Further, as shown in FIG. 4, in the AC power supply device 10, even if the generated power Ppv becomes zero, the magnitude of the stored power Pbat has been made to follow the change in the load power Ppl before that, so the stored power Pbat is It is consumed by the load circuit PL without flowing back into the commercial AC power supply SPS.

  In order to further describe the operation of the AC power supply device 10 described above, the operation of the AC power supply device 101 as a comparative example will be described in comparison with the operation of the AC power supply device 10. FIG. 5 shows a block diagram of an AC power supply system 100 that is a comparative example of the AC power supply system 1 according to the first embodiment.

  As shown in FIG. 5, an AC power supply system 100 according to a comparative example is obtained by replacing the AC power supply device 10 of the AC power supply system 1 shown in FIG. 1 with an AC power supply device 101. The AC power supply apparatus 101 is obtained by replacing the converter control unit 14 of the AC power supply apparatus 10 with a converter control unit 102.

  Then, converter control unit 102 acquires information on the power of the commercial AC signal given from the commercial AC power supply SPS side from system power monitoring unit CS_Pr. Further, converter control unit 102 acquires information on stored power from stored power monitor unit CS_BAT. Converter control unit 102 then performs control on DC / DC converter 12 to adjust the magnitude of stored power Pbat so that the power of the commercial AC signal is as small as possible.

  Next, the operation of the AC power supply apparatus 101 according to the comparative example shown in FIG. 5 will be described. FIG. 6 is a timing chart for explaining the operation of the AC power supply apparatus 101 according to the comparative example. As shown in FIG. 6, in the AC power supply system 100, the AC power supply apparatus 101 suppresses the output of the stored power Pbat during a period in which the load power Ppl is smaller than the generated power Ppv (for example, periods TM1 and TM3). Power corresponding to the power Ppv is output as an AC power signal. Then, AC power supply system 100 causes surplus power that cannot be consumed by load circuit PL to flow backward to commercial AC power supply SPS.

  Further, AC power supply system 100 compensates for insufficient power obtained by subtracting generated power Ppv from load power Ppl with stored power Pbat during a period in which generated power Ppv is lower than load power Ppl (for example, periods TM2 and TM4). During this period, there is no power to be reversely flowed to the commercial AC power supply SPS side, so the reverse flow power Pr becomes zero.

  On the other hand, in the AC power supply device 10 according to the first embodiment, since the increase / decrease of the load power Ppl is caused to follow the increase / decrease of the stored power Pbat, the generated power Ppv is used even when the generated power Ppv is smaller than the load power Ppl. It is possible to reversely flow the wiring.

  From the above description, according to the AC power supply device 10 according to the first embodiment, most of the generated power Ppv supplied from the renewable energy source can be reversely flowed to the commercial AC power supply SPS side. That is, according to the AC power supply device 10 according to the first embodiment, it is possible to reversely flow renewable energy to the system wiring as much as possible.

  Further, by using the AC power supply device 10 according to the first exemplary embodiment, it is possible to give a margin to the power supply capability on the commercial AC power supply SPS side. For example, in the AC power supply device 101 according to the comparative example, a part of the power that can flow backward to the commercial AC power supply SPS side is consumed by the load circuit, and the power supply capability on the commercial AC power supply SPS side is sufficiently reduced. I can't. On the other hand, by using the AC power supply device 101 according to the first embodiment, the power supplied from the commercial AC power supply SPS side is made zero, and almost all the power generated by the renewable energy source is supplied to the commercial AC power supply SPS side. The power supply capacity prepared on the commercial AC power supply SPS side can be greatly reduced.

  In addition, by using the AC power supply device 10 according to the first embodiment, the storage battery BAT is charged with a commercial AC signal at night when there is a surplus in power that can be supplied on the system power supply SPS side, and consumed on the system power supply side. In the daytime when there is not enough power, the load power Ppl can be supplied by the stored power Pbat of the storage battery BAT charged at night. That is, by using the AC power supply device 10 according to the first embodiment, it is possible to realize a peak shift that eliminates the difference in power consumption between nighttime and daytime on the system power supply SPS side.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 AC power supply system 10 AC power supply device 11, 12 DC / DC converter 13 DC / AC inverter 14 Converter control part 15 DC bus wiring 20 Load power detection part 21 Output storage power detection part 22 Power control part 23 PWM control part 24 Converter part 30 System Phase Detection Unit 31 Bus Voltage Control Unit 32 Inverter Power Control Unit 33 PWM Control Unit 34 Inverter Unit CS_PL Load Power Monitor Unit CS_BAT Storage Power Monitor Unit SPS Commercial AC Power Supply

Claims (11)

An output power control method for an AC power supply device that operates in conjunction with a commercial AC power supply that supplies a commercial AC signal to the system wiring,
While controlling the stored power supplied from the power storage unit to follow the load power consumed by the load circuit connected to the system wiring, the voltage of the stored power is converted and the first DC power signal is output. And
Combining the first DC power signal and the second DC power signal supplied from the renewable energy source in a DC bus wiring;
While controlling the power of the AC power signal output to the system wiring so that the bus voltage of the DC bus wiring approaches a preset bus voltage command value, the DC power transmitted through the DC bus wiring is An output power control method for an AC power supply device that converts an AC power signal.   The method for controlling the output power of an AC power supply apparatus according to claim 1, wherein the stored power is smaller than the load power.   The amount of power of the AC power signal is controlled by an inverter power command value that instructs increase or decrease of the power of the AC power signal based on a difference value between a bus voltage of the DC bus wiring and a preset bus voltage command value. The output power control method of the alternating current power supply device according to claim 1 or 2.   4. The AC power supply apparatus according to claim 3, wherein it is determined whether to increase or decrease the latest inverter power measurement value based on the inverter power command value, and the power of the AC power signal is controlled based on the determination. Output power control method.   4. The output power control method for an AC power supply apparatus according to claim 1, wherein the second DC power signal is output by converting a voltage of generated power supplied from the renewable energy source. 5. An AC power supply device that operates in conjunction with a commercial AC power supply that supplies a commercial AC signal to the system wiring,
A first DC voltage converter that converts a voltage of stored power supplied from the power storage unit and outputs a first DC power signal;
A controller that controls the first DC voltage converter so that the amount of power of the first DC power signal follows the load power consumed by the load circuit connected to the system wiring;
DC bus wiring for combining and transmitting the first DC power signal and a second DC power signal supplied from a renewable energy source;
While controlling the power of the AC power signal output to the system wiring so that the bus voltage of the DC bus wiring approaches a preset bus voltage command value, the DC power transmitted through the DC bus wiring is An inverter that converts to an AC power signal;
AC power supply apparatus having   The AC power supply apparatus according to claim 6, wherein the control unit controls the first DC voltage converter so that an amount of the stored power is equal to or smaller than an amount of the load power.   The inverter has a bus voltage control unit that outputs an inverter power command value that instructs increase / decrease of the power of the AC power signal based on a difference value between a bus voltage of the DC bus wiring and a preset bus voltage command value. The AC power supply device according to claim 6 or 7.   The inverter determines whether to increase or decrease the inverter power measurement value acquired by the output power monitor unit that monitors the output power of the inverter based on the inverter power command value, and based on the determination, The alternating current power supply device according to claim 8 which controls electric power of an alternating current power signal.   10. The alternating current according to claim 6, further comprising: a second DC voltage converter that converts a voltage of generated power supplied from the renewable energy source and outputs the second DC power signal. Power supply.   11. The AC power supply apparatus according to claim 6, further comprising: a load power monitor unit that monitors the load power; and a stored power monitor unit that monitors the stored power.

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