TWI867615B - Power regulation system, storage device and control method of power regulation system - Google Patents

Abstract

The present disclosure discloses a power regulation system. The power regulation system comprises at least one converter, a detection circuit and a controller. Each converter comprises a plurality of switches and a driving circuit. The driving circuit is electrically connected with the plurality of switches. The detection circuit is electrically connected with the converter for detecting a plurality of electric parameters and outputting a plurality of convert parameters. The controller is electrically connected with the detection circuit and the driving circuit of the converter for providing a PWM signal according to the plurality of convert parameters and providing an enable signal according to a power command of the power regulation system. The PWM signal and the power command are outputted to the driving circuit. The driving circuit controls the operation of the plurality of switches according to the PWM signal and the power command.

Description

Power regulation system, energy storage device and control method of power regulation system

This case is about a power regulation system, especially a power regulation system applied to energy storage equipment and its control method.

With the increase of renewable energy power generation equipment in the power grid, the demand for energy storage devices in the power grid has also increased. The services provided by energy storage devices to the power grid include frequency modulation services of automatic frequency control (AFC). The efficiency of energy storage devices when performing frequency modulation services is the power generation divided by the power consumption in a fixed time. The higher the efficiency of energy storage devices, the lower the power consumption. As shown in Figure 1, the power conditioning system (PCS) 3' between the energy storage device 1' and the power grid 2' can adjust the output active power according to the changes in the power grid frequency to reduce the changes in the power grid frequency and stabilize the power grid frequency. The power conditioning system 3' has cooling system loss and operation loss. The operation loss is related to the load. The smaller the load of the power conditioning system 3', the lower its efficiency. However, the frequency of the power grid 2' is stable most of the time. At this time, the output power of the power conditioning system 3' is relatively small. When the power conditioning system 3' operates at low power or zero power for a long time, the efficiency is low. In addition, in other power grid auxiliary services, there are also situations where the power conditioning system 3' operates at a relatively small output power. Therefore, improving the efficiency of the power conditioning system when it is running at low power becomes a more important issue.

Therefore, how to develop a power regulation system, energy storage equipment and control method of the power regulation system that overcomes the above shortcomings is an urgent need at present.

The purpose of this case is to provide a power regulation system that adjusts the working state of the converter according to the range of its power command, controls the converter to stop running when there is a low power command or a zero power command, and controls the converter to quickly resume operation and output electrical energy when there is a high power command. Therefore, the power regulation system of this case responds quickly when the power supply system changes to adjust the power supply system back to a stable state, and stops operating when the power supply system is stable, thereby reducing the cooling loss, operating loss and switching loss of the power regulation system, thereby improving the operating efficiency of the power regulation system.

To achieve the above-mentioned object, a more general implementation of the present invention is to provide a power regulation system, including at least one converter, a detection circuit and a controller. Each converter includes a plurality of switch elements and a driving circuit, and the driving circuit is electrically connected to the plurality of switch elements, wherein the converter has a plurality of electrical parameters. The detection circuit is electrically connected to the converter, and is used to detect the plurality of electrical parameters of the converter and output a plurality of conversion parameters. The controller is electrically connected to the detection circuit and the drive circuit of the converter, and is used to generate a pulse width modulation signal according to a plurality of conversion parameters, generate an enable signal according to the power command of the power regulation system, and output the pulse width modulation signal and the enable signal to the drive circuit, wherein the drive circuit controls the operating state of a plurality of switch elements according to the received pulse width modulation signal and the enable signal.

To achieve the above-mentioned purpose, another more general implementation of the present invention is to provide an energy storage device electrically connected to a power supply system, and comprising an energy storage unit and at least one power regulation system as described above, wherein at least one power regulation system is electrically connected between the energy storage unit and the power supply system.

To achieve the above-mentioned purpose, another more general implementation of the present case is to provide a control method for a power regulation system, wherein the power regulation system includes at least one converter, a detection circuit and a controller, wherein at least one converter includes a plurality of switch elements and a drive circuit, wherein the drive circuit is electrically connected to the plurality of switch elements, and the control method includes the following steps. Obtaining a plurality of conversion parameters of the converter and a power instruction of the power regulation system; generating a pulse width modulation signal according to the plurality of conversion parameters, and generating an enable signal according to the power instruction of the power regulation system; and controlling the operating state of the plurality of switch elements according to the pulse width modulation signal and the enable signal.

1’: Traditional energy storage device

2’: Power grid

3’: Traditional power regulation system

1, 1a, 1b, 1c, 1d, 1e: Energy storage equipment

2: Power supply system

3: Energy storage unit

4, 4a, 4b, 4c, 4d, 4e: Power regulation system

41, 41a, 41b 41c, 41d: Converter

411: Switching components

412:Drive circuit

42: Detection circuit

421: Phase-locked circuit

422: Detection filter

43: Controller

43M: Main controller

43S: From controller

44: Energy management unit

A:Curve

B:Curve

f1, f2: frequency

45: Enabling unit

46: Power control unit

461: First power regulator

462: First feedforward regulator

463: First adder

464: First current regulator

465: Second power regulator

466: Second feedforward regulator

467: Second adder

468: Second current regulator

471:Coordinate converter

472: Modulator

48: Circulating current control circuit

5: Filter

51: Filter inductor

52: Filter capacitor

53: Damping resistor

54: Bypass switch

6: System switch

Ug: grid voltage

Freq: grid frequency

Up: Grid voltage amplitude

θg: grid voltage angle

Freq_lpf: filter grid frequency

Pref: Power command

Pdis: power threshold

Pen: Power threshold

PWMdis: enable signal

Pfed: Active power feedback

idrefp: first active current reference value

idrefu: first feed-forward current

idref: Active current command

idfed: Active current feedback

Ed: First voltage command value

Qref: reactive power command

Qfed: reactive power feedback

iqrefp: first reactive current reference value

iqrefu: Second feed-forward current

iqref: reactive current command

iqfed: reactive current feedback

Eq: Second voltage command value

Eabc: three-phase control instructions

PWM signal: pulse width modulation signal

Pdis1: first power threshold

Pdis2: Second power threshold

Pdis3: The third power threshold

Pdis4: fourth power threshold

PWMdis1: first enable signal

PWMdis2: second enable signal

PWMdis3: The third enable signal

PWMdis4: the fourth enable signal

S1-S3: Steps

FIG. 1 is a schematic diagram of a circuit structure of a conventional energy storage device applied to a power supply system; FIG. 2 is a schematic diagram of a circuit structure of an energy storage device of the first embodiment of the present invention applied to a power supply system; FIG. 3A is a curve of a power control system power command changing with the power grid frequency; FIG. 3B is another curve of a power control system power command changing with the power grid frequency; FIG. 4A is a schematic diagram of a circuit structure of an energy storage device of the first embodiment of the present invention applied to a power supply system; FIG. 4B is another curve of a power control system power command changing with the power grid frequency; FIG. 4A is a schematic diagram of a circuit structure of an energy storage device of the first embodiment of the present invention applied to a power supply system; FIG. 4A is a schematic diagram of a circuit structure of an energy storage device of the first embodiment of the present invention applied to a power supply system; FIG. 4B ... FIG. 4B is a hysteresis curve corresponding to the enabling unit in FIG. 4A; FIG. 5 is a circuit structure diagram of the energy storage device of the second embodiment of the present case applied to the power supply system; FIG. 6 is a detection circuit and a detailed circuit of the controller of the energy storage device shown in FIG. 5 and a control diagram thereof; FIG. 7 is a schematic diagram of the detection circuit and the detailed circuit of the controller of the energy storage device shown in FIG. 5 and a control diagram thereof; FIG. 8 is a schematic diagram of the storage device of the third embodiment of the present case. Figure 8 is a schematic diagram of the circuit structure of the energy storage device applied to the power supply system; Figure 8 is a schematic diagram of the detection circuit and the detailed circuit of the controller of the energy storage device shown in Figure 7 and its control; Figure 9 is a schematic diagram of the circuit structure of the energy storage device of the fourth embodiment of this case applied to the power supply system; Figure 10 is a schematic diagram of the detailed circuit of the main controller of the energy storage device shown in Figure 9 and its control; Figure 11 is a schematic diagram of the circuit structure of the energy storage device of the fifth embodiment of this case applied to the power supply system; and Figure 12 is a schematic diagram of the detailed circuit of the main controller and the slave controller of the energy storage device shown in Figure 11 and its control; Figure 13 is a schematic diagram of the circuit structure of the energy storage device of the sixth embodiment of this case applied to the power supply system; and Figure 14 is a flow chart of the control method of the power regulation system of this case.

Some typical embodiments that embody the features and advantages of this case will be described in detail in the following description. It should be understood that this case can have various variations in different forms, all of which do not deviate from the scope of this case, and the descriptions and drawings therein are essentially for illustrative purposes rather than for limiting this case.

Please refer to Figure 2, which is a schematic diagram of the circuit structure of the energy storage device of the first embodiment of the present case applied to the power supply system. As shown in Figure 2, the energy storage device 1 is electrically connected to the power supply system 2 to perform power conversion, wherein the power supply system 2 has a main electrical parameter, such as the voltage or frequency of the power supply system 2. The energy storage device 1 includes an energy storage unit 3 and a power regulation system 4. The energy storage unit 3 can provide DC power.

The power regulation system 4 includes a converter 41, a detection circuit 42 and a controller 43. The converter 41 includes a plurality of switching elements 411 and a driving circuit 412, and the converter 41 has a plurality of electrical parameters that are related to the output power of the converter 41, such as the output voltage or output current of the converter 41. In this embodiment, the plurality of switching elements 411 are electrically connected to the energy storage unit 3, and the number of the plurality of switching elements 411 is six, and the six switching elements 411 constitute three bridge arms connected in parallel to each other, and each bridge arm has two switching elements 411 connected in series. The driving circuit 412 is electrically connected to the plurality of switching elements 411 to control the operating state of the plurality of switching elements 411.

The detection circuit 42 is electrically connected to the converter 41, and is used to detect a plurality of electrical parameters of the converter 41 and output a plurality of conversion parameters. The controller 43 is electrically connected to the detection circuit 42 and the drive circuit 412 of the converter 41. The controller 43 generates a pulse width modulation signal according to the plurality of conversion parameters output by the detection circuit 42, and the controller 43 further outputs an enable signal according to the power command of the power regulation system 4. The power command of the power regulation system 4 can be determined according to the main electrical parameters of the power supply system 2, and its detailed features will be described later. The controller 43 transmits the pulse width modulation signal and the enable signal to the driving circuit 412. The driving circuit 412 controls the operation status of the plurality of switch elements 411 of the converter 41 according to the pulse width modulation signal and the enable signal provided by the controller 43 to adjust the output power of the converter 41.

According to some embodiments of the present invention, the energy storage device 1 needs to provide auxiliary services for the power grid, such as frequency modulation services and voltage regulation services. When providing auxiliary services for the power grid, the power provided by the power regulation system 4 needs to follow the power instruction of the power regulation system 4. When the power instruction of the power regulation system 4 is relatively small, for example, less than or equal to a preset threshold, the power regulation system 4 operates in a low-power or zero-power condition, and the controller 43 outputs an enable signal with a set level. The drive circuit 412 receives the enable signal with a set level, blocks the pulse width modulation signal, stops the operation of the plurality of switch elements 411 of the converter 41, and the power regulation system 4 enters a hot standby state. Since the power regulation system 4 stops switching, there is no cooling system loss, operating loss and switching loss. When the power instruction of the power regulation system 4 is large, for example, greater than the preset threshold, the controller 43 changes the enable signal (for example, outputs an enable signal with an opposite level). The drive circuit 412 receives the changed enable signal and normally outputs a pulse width modulation signal, so that the multiple switch elements 411 of the converter 41 operate normally, and the power regulation system 4 exits the hot standby state and quickly restores power output. The set level in this embodiment is, for example, a high level, and the opposite level is, for example, a low level or a zero level, but the present invention is not limited thereto.

As can be seen from the above, the power regulation system 4 of the energy storage device 1 of this case adjusts the working state of the converter 41 with reference to the range of its power command, controls the converter 41 to stop running when there is a low power command or a zero power command, and controls the converter 41 to quickly resume running and output electric energy when there is a high power command. Therefore, compared with the traditional power regulation system, the power regulation system 4 of this case responds quickly when the power supply system 2 changes to adjust the power supply system 2 back to a stable state, and stops operating when the power supply system 2 is stable, reducing the cooling loss, operating loss and switching loss of the power regulation system 4, thereby improving the operating efficiency of the power regulation system 4.

Please continue to refer to FIG. 2. The controller 43 of the power regulation system 4 includes an energy management unit 44, an enabling unit 45, and a power control unit 46. The energy management unit 44 is located in the controller 43 and is electrically connected to the detection circuit 42 to receive one or more conversion parameters output by the detection circuit 42, and output a power instruction according to the received conversion parameters, wherein the received conversion parameters are the main electrical parameters of the power supply system 2 calculated according to the electrical parameters of the converter, such as the calculated frequency or voltage amplitude of the power supply system 2. In some embodiments, the energy management unit 44 may be independent of the controller 43 and located in the energy management system (EMS). The enabling unit 45 is electrically connected to the energy management unit 44 to receive the power command provided by the energy management unit 44. The enabling unit 45 further has a preset power threshold. The enabling unit 45 generates and outputs an enabling signal to the driving circuit 412 according to the comparison result between the power command and the power threshold. The power control unit 46 is electrically connected to the enabling unit 45 and the detection circuit 42 to receive the enabling signal and a plurality of conversion parameters, and generates and outputs a pulse width modulation signal to the driving circuit 412 according to the enabling signal and the plurality of conversion parameters. When the driver circuit 412 confirms that the enable signal provided by the controller 43 is at a set level, it means that the power command is less than or equal to the power threshold value. The driver circuit 412 blocks the pulse width modulation signal and controls the multiple switch elements 411 of the converter 41 to stop operating, so that the output power of the converter 41 is zero. When the driver circuit 412 confirms that the enable signal provided by the controller 43 is not at a set level, in other words, when the enable signal is at another level, it means that the power command is greater than the power threshold value. The driver circuit 412 controls the multiple switch elements 411 to operate according to the pulse width modulation signal, so that the output power of the converter 41 is adjusted according to the power command.

In this embodiment, the power regulation system 4 further includes a filter 5. The filter 5 includes a filter inductor 51, a filter capacitor 52 and a damping resistor 53. The filter inductor 51 is electrically connected between the converter 41 and the power supply system 2, the first end of the damping resistor 53 is electrically connected to the connection point between the converter 41 and the power supply system 2, the filter capacitor 52 is electrically connected to the second end of the damping resistor 53, that is, the damping resistor 53 is electrically connected between the filter inductor 51 and the filter capacitor 52, wherein the damping resistor 53 is used to suppress the resonance of the power regulation system 4. In one embodiment, a system switch 6 is also provided between the filter 5 of the power regulation system 4 and the power supply system 2 to switch the power regulation system 4 and the power supply system 2 according to the demand. When the system switch 6 is closed, the energy storage device 1 is in the grid-connected mode, and when the system switch 6 is disconnected, the energy storage device 1 is in the off-grid mode.

According to some embodiments of the present invention, the power supply system 2 is a power grid, the system switch 6 is closed, and the energy storage device 1 provides automatic frequency control (AFC) for the power grid. Please refer to Figure 3A in conjunction with Figure 2, wherein Figure 3A is a curve showing the power command of the power regulation system changing with the power grid frequency. As shown in Figure 3A, the horizontal axis is the power grid frequency, the vertical axis is the power command, the power command corresponding to the origin is zero, and the power grid frequency is the rated value (e.g., 50HZ, 60HZ...). Taking a 50HZ power grid as an example, the frequency corresponding to point C is, for example, 49.98HZ, and the frequency corresponding to point D is, for example, 50.02HZ. In this embodiment, the energy management unit 44 includes the curve shown in FIG. 3A, and determines the power command based on the preset curve and the received grid frequency. The energy management unit 44 determines the received grid frequency, that is, compares the received grid frequency with the frequencies of points C and D. When the energy management unit 44 confirms that the grid frequency is within the set points C and D, for example, when the grid frequency is any frequency between C and D, the energy management unit 44 determines that the power command is zero or a value close to zero. When the grid frequency is any frequency between C and D, it means that the grid frequency is stable, and the power regulation system 4 may not perform automatic frequency control. In order to improve the efficiency of the power regulation system 4, in one embodiment, the power instruction provided by the energy management unit 44 is a first type of power instruction, wherein the first type of power instruction is less than or equal to the power threshold, and the driving circuit 412 blocks the pulse width modulation signal according to the enable signal to control the plurality of switch elements 411 of the converter 41 to stop operating. For example, the power threshold is 1%*P ₀ , wherein P ₀ is the rated power of the energy storage device. When the energy management unit 44 confirms that the received grid frequency is outside the frequency range set by C and D, the energy management unit 44 determines the power instruction according to curve A or curve B. For example, when the received grid frequency is less than the frequency corresponding to point C, the energy management unit 44 determines the power instruction according to curve A; when the received grid frequency is greater than the frequency corresponding to point D, the energy management unit 44 determines the power instruction according to curve B. When the grid frequency is not within the frequency range set by C and D, it indicates that the grid frequency is unstable, and the power regulation system 4 performs automatic frequency control. In one embodiment, the power instruction provided by the energy management unit 44 is a second-class power instruction, and the drive circuit 412 outputs a pulse width modulation signal according to the enable signal to control the continuous operation of the plurality of switch elements 411 of the converter 41. The second-class power instruction is greater than the power threshold, for example, the second-class power instruction is greater than 10%*P ₀ . In this embodiment, the first type of power instruction and the second type of power instruction are discontinuous. When the main electrical parameter of the power supply system 2 moves from within the set parameter range to outside the set parameter range, the power instruction provided by the energy management unit 44 jumps from the first type of power instruction to the second type of power instruction, where the main electrical parameter can be the frequency or voltage amplitude of the power supply system, etc.

Points C and D in Figure 3A are set according to the regulations of the power grid company, and the parameter range can also be designed by yourself. Figure 3B is another curve showing that the power command of the power regulation system changes with the power grid frequency. Please refer to Figure 3B, the frequency range is extended to points f1 and f2, where the frequency corresponding to point f1 is less than the frequency corresponding to point C, and the frequency corresponding to point f2 is greater than the frequency corresponding to point D. The energy management unit 44 determines the power command according to the curve shown in Figure 3B, and on the basis of achieving a stable power grid frequency, expands the parameter range of the power regulation system 4 stopping operation, and further improves the efficiency of the power regulation system 4.

Please refer to Figure 4A in conjunction with Figure 2, wherein Figure 4A is a detailed circuit diagram of the detection circuit and controller of the energy storage device shown in Figure 2 and its control diagram. In this embodiment, the power supply system is explained using the power grid as an example, but the present invention is not limited to this. As long as it is a power source with stable voltage and frequency, it can be considered as the power supply system of the present invention. The detection circuit 42 includes a phase-locked circuit 421 and a detection filter 422. The phase-locked circuit 421 receives the main electrical parameters of the power supply system 2, such as the grid voltage Ug, and obtains the grid frequency Freq, the grid voltage amplitude Up, and the grid voltage angle θg through phase-locked loop control or zero-crossing detection. It should be noted that the output voltage Uabc of the power regulation system 4 is equal to the grid voltage, and the detection circuit 42 detecting the output voltage Uabc is equivalent to detecting the grid voltage Ug. The detection filter 422 filters the grid frequency Freq to obtain the steady-state value Freq_lpf of the grid frequency over a period of time. The energy management unit 44 has a preset frequency-power curve (for example, the preset curve in Figure 3A or Figure 3B), and the energy management unit 44 obtains the active power instruction Pref based on the matching result of the steady-state value Freq_lpf of the grid frequency and the frequency-power curve. Generally, the grid frequency is stabilized by active power, so the power instruction in this embodiment is the active power instruction Pref, but the present invention is not limited to this. The detection circuit 42 also includes a calculation circuit (not shown), which receives the output current Iabc and output voltage Uabc (i.e., grid voltage Ug) of the converter 41, and calculates multiple conversion parameters, such as active power feedback Pfed, reactive power feedback Qfed, active current feedback Idfed, and reactive current feedback Iqfed, and provides these conversion parameters to the power control unit 46.

As shown in FIG. 4A, the enabling unit 45 in this embodiment adopts hysteresis control. Please refer to FIG. 4A and FIG. 4B together, wherein FIG. 4B is the hysteresis curve corresponding to the enabling unit in FIG. 4A. The enabling unit 45 receives the power command Pref, the preset power threshold Pdis and Pen, and the setting level of the enabling signal PWMdis is the digital signal 1. As shown in FIG. 4B, when the power command Pref increases from zero, the enabling unit 45 outputs the enabling signal PWMdis according to curve 1, that is, when the power command Pref is less than the power threshold Pen, the enabling signal PWMdis is 1 level; when the power command Pref increases to be greater than the power threshold Pen, the enabling signal PWMdis changes to zero level. When the power command Pref decreases, the enabling unit 45 outputs the enabling signal PWMdis according to curve 2, that is, when the power command Pref is greater than the power threshold value Pdis, the enabling signal PWMdis is zero level; when the power command Pref decreases to less than the power threshold value Pdis, the enabling signal PWMdis changes to 1 level.

In another embodiment, the enabling unit does not use hysteresis control, for example, only the power threshold Pen or Pdis is set. The enabling unit 45 receives the power command Pref and compares it with the power threshold. When the power command Pref is less than or equal to the power threshold, the enabling signal PWMdis is a set level (for example, a digital signal of 1), and when the power command Pref is greater than or equal to the power threshold, the enabling signal PWMdis is not a set level (for example, a digital signal of 0).

The power control unit 46 includes a first power regulator 461, a first feedforward regulator 462, a first adder 463, a first current regulator 464, a second power regulator 465, a second feedforward regulator 466, a second adder 467, a second current regulator 468, a coordinate converter 471 and a modulator 472. The first power regulator 461 receives an active power command Pref, an active power feedback Pfed and an enable signal PWMdis to output a first active current reference value idrefp. Specifically, the error between the active power command Pref and the active power feedback Pfed is calculated, and the error is adjusted (e.g., PI adjustment) to obtain the first active current reference value idrefp. When the enable signal PWMdis is at a set level (for example, the digital signal is 1), the output of the first power regulator 461 is cleared to make the output first active current reference value idrefp zero. Clearing the output of the first power regulator 461 prevents current shock when the power regulation system 4 re-outputs power. When the enable signal PWMdis is not at a set level (for example, the digital signal is 0), the output of the first power regulator 461 is not cleared, and the first power regulator 461 normally outputs the first active current reference value idrefp, that is, the power control unit 46 uses the first power regulator 461 to achieve active power control.

差，對該

差進行調節(例如PI調節)得到第一電壓指令值Ed。當使能訊號PWMdis為設定電平(例如數位訊號為1)時改變第一電壓指令值Ed為初始值，即改變第一電壓指令值Ed為採樣的電網電壓的d軸分量，以防止重新開啟訊號時的電流衝擊。當使能訊號PWMdis不為設定電平(例如數位訊號為0)時正常輸出第一電壓指令值Ed，即功率控制單元46利用第一電流調節器464達到有功電流控制。 The first feedforward regulator 462 receives the active power command Pref and the grid voltage amplitude Up, and outputs the first feedforward current idrefu, wherein the active power command Pref is divided by the grid voltage amplitude Up to obtain the first feedforward current idrefu. The first adder 463 adds the first active current reference value idrefp and the first feedforward current idrefu to output the active current command idref. When the enable signal PWMdis is a set level (for example, the digital signal is 1), the first active current reference value idrefp is cleared, and the active current command idref is equal to the first feedforward current idrefu, that is, the initial value without adjusting the active current. The first current regulator 464 receives the enable signal PWMdis, the active current command idref and the active current feedback idfed to output the first voltage command value Ed. Specifically, the difference between the active current command idref and the active current feedback idfed is calculated.

Poor, yes

The first voltage command value Ed is obtained by adjusting the difference (e.g., PI adjustment). When the enable signal PWMdis is at a set level (e.g., the digital signal is 1), the first voltage command value Ed is changed to an initial value, that is, the first voltage command value Ed is changed to the d-axis component of the sampled grid voltage to prevent current shock when the signal is reopened. When the enable signal PWMdis is not at a set level (e.g., the digital signal is 0), the first voltage command value Ed is output normally, that is, the power control unit 46 uses the first current regulator 464 to achieve active current control.

The second power regulator 465 receives the reactive power command Qref, the reactive power feedback Qfed and the enable signal PWMdis to output the first reactive current reference value iqrefp. Specifically, the error between the reactive power command Qref and the reactive power feedback Qfed is calculated, and the error is adjusted (e.g., PI adjustment) to obtain the first reactive current reference value iqrefp. When the enable signal PWMdis is a set level (e.g., the digital signal is 1), the output of the second power regulator 465 is cleared to zero, so that the output first reactive current reference value iqrefp is zero. The output of the second power regulator 465 is cleared so that no current shock will be generated when the power regulation system 4 re-outputs power. When the enable signal PWMdis is not at the set level (for example, the digital signal is 0), the output of the second power regulator 465 is not cleared, and the second power regulator 465 normally outputs the first reactive current reference value iqrefp, that is, the power control unit 46 uses the second power regulator 465 to achieve reactive power control.

差，對該

差進行調節(例如PI調節)得到第二電壓指令值Eq。當使能訊號為設定電平(例如數位訊號為1)時改變第二電壓指令值Eq為初始值，即改變第二電壓指令值Eq為採樣的電網電壓的q軸分量，以防止重新開啟訊號時的電流衝擊。當使能訊號PWMdis不為設定電平(例如數位訊號為0)時正常輸出第二電壓指令值Eq，即功率控制單元46利用第二電流調節器468達到無功電流控制。坐標變換器471接收第一電壓指令值Ed及第二電壓指令值Eq，利用電網電壓角度θg對第一電壓指令值Ed及第二電壓指令值Eq進行坐標變換以輸出三相控制指令Eabc。調製器472接收三相控制指令Eabc，以輸出脈寬調變訊號PWM signal。 The second feedforward regulator 466 receives the reactive power command Qref and the grid voltage amplitude Up, and outputs the second feedforward current iqrefu, wherein the reactive power command Qref is divided by the grid voltage amplitude Up to obtain the second feedforward current iqrefu. The second adder 467 adds the first reactive current reference value iqrefp and the second feedforward current iqrefu to output the reactive current command iqref. When the enable signal PWMdis is a set level (for example, the digital signal is 1), the first reactive current reference value iqrefp is cleared, and the reactive current command iqref is equal to the second feedforward current iqrefu, that is, the initial value without adjusting the reactive current. The second current regulator 468 receives the enable signal PWMdis, the reactive current command iqref and the reactive current feedback iqfed to output the second voltage command value Eq. Specifically, the reactive current command iqref and the reactive current feedback iqfed are calculated.

Poor, yes

The difference is adjusted (for example, PI adjustment) to obtain the second voltage command value Eq. When the enable signal is a set level (for example, the digital signal is 1), the second voltage command value Eq is changed to an initial value, that is, the second voltage command value Eq is changed to the q-axis component of the sampled grid voltage to prevent current shock when the signal is reopened. When the enable signal PWMdis is not a set level (for example, the digital signal is 0), the second voltage command value Eq is output normally, that is, the power control unit 46 uses the second current regulator 468 to achieve reactive current control. The coordinate converter 471 receives the first voltage command value Ed and the second voltage command value Eq, and uses the grid voltage angle θg to perform coordinate conversion on the first voltage command value Ed and the second voltage command value Eq to output the three-phase control command Eabc. The modulator 472 receives the three-phase control command Eabc to output a pulse width modulation signal PWM signal.

A first feedforward regulator 462 and a second feedforward regulator 466 are added to the power control unit 46 to improve the rapidity of power control. In other embodiments, no feedforward regulator may be provided, or only one feedforward regulator may be provided, such as the first feedforward regulator 462 or the second feedforward regulator 466.

In some embodiments, as shown in FIG. 4A , the controller 43 is implemented by a control chip, for example, the controller is implemented by a DSP control chip, and the DSP control chip is responsible for completing signal sampling, loop control, and signal modulation, and outputting an enable signal PWMdis and a pulse width modulation signal PWM signal to the drive circuit 412. The drive circuit 412 is implemented by a control chip (for example, an FPGA control chip). When the power instruction is lower, it is a first type of power instruction, for example, the power instruction is less than a preset threshold or a preset threshold range, the enable signal PWMdis is a set level, and the drive circuit 412, for example, uses hardware to set the pulse width modulation signal PWM signal to zero.

In another embodiment, the controller 43 is implemented by a DSP control chip and an FPGA control chip. The DSP control chip is responsible for completing signal sampling and loop control, and outputting the three-phase control instruction Eabc to the FPGA control chip. The FPGA control chip is responsible for modulating the three-phase control instruction Eabc to output the pulse width modulation signal PWM signal. The drive circuit 412 is implemented by a control chip (for example, another FPGA control chip). When the power instruction is lower, it is a first type of power instruction. The drive circuit 412, for example, uses hardware to set the pulse width modulation signal PWM signal to zero.

In another embodiment, the controller 43 is implemented by a control chip, for example, the controller 43 is implemented by a DSP control chip, and the modulator 472 is implemented by another control chip, for example, the modulator 472 is implemented by an FPGA control chip. The controller is responsible for completing signal sampling and loop control, and outputting an enable signal PWMdis and a three-phase control instruction Eabc to the modulator 472. When the power instruction is lower, it is a first type of power instruction, for example, the power instruction is less than a preset threshold or a preset threshold range, the enable signal PWMdis is a set level, and the modulator 472 (i.e., the FPGA chip) sets the pulse width modulation signal PWM signal to zero by software, for example. At this time, the modulator 472 is functionally classified as a driver circuit, that is, the driver circuit may include a modulator and a driver, for example, the modulator is implemented by an FPGA control chip, and the driver is implemented by another FPGA control chip. In this embodiment, the pulse width modulation signal provided by the controller to the driver circuit corresponds to a three-phase control instruction, that is, the pulse width modulation signal of the present invention may also include a three-phase control instruction.

It should be noted that the present disclosure is not limited to this, and the controller and/or driver circuit can also be implemented in other ways, such as by building an analog circuit. That is, the controller and/or driver circuit disclosed in the present disclosure includes one or more of the control chip, computing program, processor, analog circuit and other structures that can realize the above functions.

In some embodiments, the energy management unit 44 not only provides power instructions according to the main electrical parameters of the power supply system 2, but also provides power instructions according to other parameters. The energy storage unit 3 in the energy storage device 1 is a battery unit, such as a battery cabinet, and the energy storage unit 3 has a charge state, and the charge state reflects the percentage value of the remaining capacity in the energy storage unit 3. Compared with the previous embodiment, the power instruction of the power regulation system in this embodiment can be determined according to the main electrical parameters of the power supply system 2 and the charge state of the energy storage unit 3. For the simplicity of the specification, this embodiment mainly describes the differences. FIG. 5 is a schematic diagram of the circuit structure of the energy storage device of the second embodiment of the present case applied to the power supply system, and FIG. 6 is a schematic diagram of the detection circuit and the detailed circuit of the controller of the energy storage device shown in FIG. 5 and its control. Please refer to FIG. 5 and FIG. 6. The energy management unit 44 also receives the state of charge of the energy storage unit 3 (indicated by SOC in FIG. 5 and FIG. 6), for example, receives the state of charge (SOC) from the battery management system (BMS). The energy management unit 44 includes a preset charge range, for example, the remaining capacity in the energy storage unit 3 is between 40% and 75%. The energy management unit 44 compares the main electrical parameters of the power supply system 2 with the set parameter range, and at the same time compares the charge state of the energy storage unit 3 with the set charge range. When the energy management unit 44 confirms that the main electrical parameters of the power supply system 2 are within the set parameter range, and confirms that the charge state of the energy storage unit 3 is within the set charge range, the power instruction provided by the energy management unit 44 is a first-class power instruction. When the energy management unit 44 confirms that the main power parameter of the power supply system 2 is outside the set parameter range, and/or confirms that the charge state of the energy storage unit 3 is outside the set charge range, that is, when the main power parameter of the power supply system 2 is not within the set parameter range or the charge state of the energy storage unit 3 is not within the set charge range, the power instruction provided by the energy management unit 44 is the second type of power instruction. In this embodiment, the first type of power instruction and the second type of power instruction are not continuous. When the main power parameter of the power supply system 2 moves from within the set parameter range to outside the set parameter range, or the charge state of the energy storage unit 3 moves from within the set charge range to outside the set charge range, the power instruction provided by the energy management unit 44 jumps from the first type of power instruction to the second type of power instruction.

Please refer to FIG. 7, which is a schematic diagram of the circuit structure of the energy storage device of the third embodiment of the present case applied to the power supply system. Compared with the power regulation system 4 of the energy storage device 1 shown in FIG. 2, which only includes a single converter 41, the power regulation system 4b of the energy storage device 1b of the present embodiment includes N converters 41, where N is a positive integer, for example, four converters 41, and the four converters 41 are connected in parallel. Similar to the power regulation system 4 of the energy storage device 1 shown in FIG. 2, the power regulation system 4b of the energy storage device 1b of the present embodiment includes a single detection circuit 42 and a controller 43. The controller 43 may be a centralized controller, which means that the power regulation system 4b utilizes a single detection circuit 42 and a centralized controller 43 to control four converters 41. To simplify the diagram, the electrical connection relationship between the detection circuit 42 and the controller 43 of FIG. 7 is not shown, but it can be clearly seen that the electrical connection relationship is similar to that of the detection circuit 42 and the controller 43 shown in FIG. 2. The controller 43 outputs four pulse width modulation signals according to a plurality of conversion parameters, and the four pulse width modulation signals are respectively output to the driving circuits in the four converters 41 (similar to FIG. 2), and the controller 43 further outputs at least one enable signal according to the power command, and each enable signal is output to the driving circuit in the corresponding converter 41 (similar to FIG. 2). The power regulation system 4b of this embodiment also includes N filters 5, for example, four filters 5, and the structure of each filter 5 is similar to the filter 5 in FIG. 2, which will not be repeated here.

Please refer to FIG. 8 in conjunction with FIG. 7, where FIG. 8 is a schematic diagram of the detection circuit and the detailed circuit of the controller of the energy storage device shown in FIG. 7 and its control method. The detailed circuit and its control method of this embodiment are similar to the detailed circuit and its control method of FIG. 4A, but the enabling unit 45 of this embodiment receives the power command and compares it with four power thresholds, for example, the power command Pref is compared with the first power threshold Pdis1, the second power threshold Pdis2, the third power threshold Pdis3 and the fourth power threshold Pdis4, where the power command Pref is the average power command of the converter 41 in the working state, for example, obtained by dividing the total power command of the energy storage device 1b by the number of converters 41 in the working state. The first power threshold value Pdis1 is less than the second power threshold value Pdis2, the second power threshold value Pdis2 is less than the third power threshold value Pdis3, and the third power threshold value Pdis3 is less than the fourth power threshold value Pdis4. When the power command Pref is less than the fourth power threshold value Pdis4 and greater than or equal to the third power threshold value Pdis3, the fourth enable signal PWMdis4 is a set level (for example, the digital signal is 1), and the switch element in the fourth converter 41 stops operating. When the power command Pref is less than the third power threshold value Pdis3 and greater than or equal to the second power threshold value Pdis2, the third enable signal PWMdis3 and the fourth enable signal PWMdis4 are set levels, and the switch element in the third converter 41 and the switch element in the fourth converter 41 stop operating. When the power command Pref is less than the second power threshold value Pdis2 and greater than or equal to the first power threshold value Pdis1, the second enable signal PWMdis2, the third enable signal PWMdis3 and the fourth enable signal PWMdis4 are set to the set level, so that the switching element in the second converter 41, the switching element in the third converter 41 and the switching element in the fourth converter 41 stop operating. When the power command Pref is less than the first power threshold value Pdis1, the first enable signal PWMdis1, the second enable signal PWMdis2, the third enable signal PWMdis3 and the fourth enable signal PWMdis4 are set to the set level (for example, the digital signal is 1), so that the switching element in the first converter 41, the switching element in the second converter 41, the switching element in the third converter 41 and the switching element in the fourth converter 41 stop operating. When the power command Pref is greater than the fourth power threshold Pdis4, the four enable signals PWMdis are not set to the set level (for example, the digital signal is 0), so that the output power of each converter 41 is adjusted according to the power command Pref. The power regulation system 4b of this embodiment can determine the number of converters 41 to stop running according to the power command to improve the conversion efficiency under light load.

The power control circuit in the controller 43 includes, for example, the first power regulator 461, the first feedforward regulator 462, the first adder 463, the second power regulator 465, the second feedforward regulator 466 and the second adder 467 in FIG. 4A; the current control circuit includes, for example, the first current regulator 464 and the second current regulator 468 in FIG. 4A. However, in this embodiment, the power feedback and the current feedback are both the average values of the converter 41 in the working state. When the first enable signal PWMdis1, the second enable signal PWMdis2, the third enable signal PWMdis3 and the fourth enable signal PWMdis4 are all at the set level, the output of the power control loop and the current control loop will be cleared, and the first voltage command value Ed and the second voltage command value Eq will be forced to the initial value.

In other embodiments, the enable unit 45 in FIG8 may also only set a power threshold. When the power command Pref is small, that is, when the power regulation system is lightly loaded, the four converters stop running at the same time. The controller 43 generates four pulse width modulation signals PWM signa11/2/3/4 and an enable signal PWMdis, which are output to the drive circuits of the four converters 41 respectively. It should be noted that the controller in FIG8 may also include a circulating current control circuit 48 for controlling the circulating current between the four converters 41. The existing circulating current control method may be adopted, or the circulating current control circuit 48 may be adjusted according to the number of converters in working state.

Please refer to Figures 9 and 10, wherein Figure 9 is a schematic diagram of the circuit structure of the energy storage device of the fourth embodiment of the present case applied to the power supply system, and Figure 10 is a detailed circuit diagram of the slave controller of the energy storage device shown in Figure 9 and its control schematic diagram. Compared with the power regulation system 4b of the energy storage device 1b shown in Figure 7, which only uses a single detection circuit 42 and a centralized controller 43 to control four converters 41, the controller of the power regulation system 4c of the energy storage device 1c of this embodiment includes a master controller 43M and three slave controllers 43S, that is, a master-slave control mode is adopted, for example, the controller corresponding to the converter 41a is the master controller 43M, and the controllers corresponding to the converters 41b-41d are the slave controllers 43S. Compared with the third embodiment, the current control circuit in the main controller 43M of this embodiment receives the first enable signal PWMdis1 instead of four enable signals, and determines whether to clear the output according to the first enable signal PWMdis1, the coordinate converter 471 outputs a three-phase control instruction Eabc, and the modulator 472 outputs the pulse width modulation signal PWM signal1 of the converter 41a. The main controller 43M outputs enable signals to the drive circuits of the four converters 41b-41d respectively, and the enable signals output to the drive circuits of the four converters can be the same or different. As shown in FIG. 10 , each slave controller 43S includes a first current regulator 464 and a second current regulator 468 of a current control circuit and a circulating current control circuit 48, which are used to receive the current feedback provided by the detection circuit 42, the current command provided by the master controller 43M and the second enable signal PWMdis2, and output the pulse width modulation signal PWM signal to the drive circuit. For example, in FIG. 10 , taking the slave controller 43S corresponding to the converter 41b as an example, the slave controller 43S receives the current feedback idfed and iqfed provided by the detection circuit 42, the current command idref and iqref provided by the master controller 43M and the second enable signal PWMdis2, and outputs the pulse width modulation signal PWM signal2 to the drive circuit of the converter 41b. However, the functions executed by the master controller and the functions executed by the slave controller are not limited to this and can be flexibly designed. In another embodiment, the main controller 43M may only output the enable signal PWM dis1 to the driving circuit of the converter 41a, and the slave controller may output the enable signal PWM dis2/3/4 to the driving circuit of the corresponding converter, for example, the slave controller 43S corresponding to the converter 41c may output the enable signal PWM dis3 and the pulse width modulation signal PWM signal3 to the driving circuit of the converter 41c.

Please refer to Figures 11 and 12, wherein Figure 11 is a schematic diagram of the circuit structure of the energy storage device of the fifth embodiment of the present case applied to the power supply system, and Figure 12 is a detailed circuit diagram of the master controller and slave controller of the energy storage device shown in Figure 11 and its control schematic diagram. As shown in Figure 11, the controller of the power regulation system 4d adopts a master-slave control mode, including a centralized controller and four slave controllers, each slave controller communicates with the centralized controller and is used to control the corresponding converter 41. Compared with the third embodiment, as shown in Figure 12, the master controller 43M of this embodiment includes an energy management unit 44, an enabling unit 45 and power control circuits 461, 462, 463, 465, 466, 467, but does not include a current control circuit. The slave controller 43S in Figure 12 is the same as the slave controller in Figure 10, and will not be repeated here. The centralized controller and the functions executed by the slave controller can be flexibly designed and distributed.

In some embodiments, in order to reduce the loss of the filter, a bypass switch is added to the filter. Please refer to Figure 13, which is a schematic diagram of the circuit structure of the energy storage device of the sixth embodiment of the present case applied to the power supply system. As shown in the figure, each filter 5 of the power regulation system 4e of this embodiment further includes a bypass switch 54, which is connected in parallel to the damping resistor 53. When the bypass switch is closed, the parallel damping resistor 53 is short-circuited to reduce the resistance loss and improve the efficiency of the power regulation system. The power regulation system 4e can determine the number of closed bypass switches according to the strength of the power supply system 2. The short circuit ratio (SCR) is usually used to characterize the strength of the power supply system, where the short circuit ratio is obtained by dividing the short circuit capacity of the power supply system by the capacity of the energy storage device. The larger the short-circuit ratio is, the stronger the power supply system is, and the smaller the impact on the power supply system after the energy storage device is connected is, that is, the more stable the power supply system is. When the short-circuit ratio of the power supply system 2 is relatively high, for example, when the short-circuit ratio is greater than 8, the bypass switches 54 of the two filters 5 are controlled, for example, the bypass switches 54 of the second filter 5 and the fourth filter 5 are controlled to be closed, so that the corresponding damping resistors 53 cannot function, thereby reducing resistance loss. When the short-circuit ratio of the power supply system 2 is relatively low, for example, when the short-circuit ratio is less than 3, the bypass switches 54 of the four filters 5 are controlled to be disconnected, so that the corresponding damping resistors 53 continue to function. In other words, the power regulation system 4d of this embodiment can switch the number of bypass switches on or off according to the strength of the power supply system 2. When the short circuit is relatively high, multiple bypass switches are controlled to close, so that the damping resistors of multiple filters are short-circuited, so as to achieve the effect of reducing resistance loss and further improve the efficiency of the power regulation system.

All the above-mentioned power regulation systems are explained using the function of automatic frequency control as an example. In some embodiments, the above-mentioned control method can also be used when the power regulation system is applied to other functions. For example, the above-mentioned control method can also be used when the power regulation system is applied to functions such as voltage support and frequency change mitigation, so as to simultaneously achieve the advantages of meeting functional requirements, reducing losses and improving efficiency. When the power regulation system is applied to voltage support, the main electrical parameter of the power supply system is the voltage amplitude, and the power command is determined according to the voltage amplitude, and the power command corresponds to the reactive power command. When the power regulation system is applied to frequency change mitigation, the main electrical parameter of the power supply system is the frequency change rate, and the power command is determined according to the frequency change rate, and the power command corresponds to the active power command.

Please refer to Figure 14, which is a flow chart of the control method of the power regulation system of this case. Execute step S1 to obtain multiple conversion parameters of the converter 41 and the power instruction of the power regulation system 4. Execute step S2 to generate a pulse width modulation signal according to the multiple conversion parameters, and generate an enable signal according to the power instruction of the power regulation system 4. Execute step S3 to control the operating state of multiple switch elements 411 according to the pulse width modulation signal and the enable signal.

During the operation of the energy storage device, the control mode of blocking the pulse width modulation signal when executing the above-mentioned low power instruction can be determined according to the instructions of the energy management system (EMS). When the above-mentioned control mode is determined to be executed according to the instructions of the EMS (such as the superior enable signal), the function is enabled (such as the controller executes the relevant program or step), and the power regulation system enters the hot standby state when the power is low; when the above-mentioned control mode is determined not to be executed according to the instructions of the EMS, the function is shielded (such as the controller shields the relevant program or step), regardless of whether the power instruction is high or low, the power regulation system performs PWM modulation to make the output power follow the power instruction.

In summary, the power regulation system of the energy storage device in this case adjusts the working state of the converter according to the range of its power command, controls the converter to stop running when there is a low power command or a zero power command, and controls the converter to quickly resume operation and output electric energy when there is a high power command. Therefore, the power regulation system in this case responds quickly when the power supply system changes to adjust the power supply system back to a stable state, and stops operating when the power supply system is stable, reducing the cooling loss, operating loss and switching loss of the power regulation system, thereby improving the operating efficiency of the power regulation system.

1: Energy storage equipment

2: Power supply system

3: Energy storage unit

4: Power regulation system

41: Converter

411: Switching components

412:Drive circuit

42: Detection circuit

43: Controller

44: Energy management unit

45: Enabling unit

46: Power control unit

5: Filter

51: Filter inductor

52: Filter capacitor

53: Damping resistor

6: System switch

Claims (23)

A power regulation system includes: at least one converter, each of which includes a plurality of switch elements and a driving circuit, the driving circuit being electrically connected to the plurality of switch elements, wherein the at least one converter has a plurality of electrical parameters; a detection circuit electrically connected to the at least one converter, for detecting the plurality of electrical parameters of the at least one converter and outputting a plurality of conversion parameters; and a controller, The driving circuit is electrically connected to the detection circuit and the at least one converter, and is used to generate a pulse width modulation signal according to the plurality of conversion parameters, generate an enable signal according to a power instruction of the power regulation system, and output the pulse width modulation signal and the enable signal to the driving circuit; wherein the driving circuit controls the operating state of the plurality of switch elements according to the received pulse width modulation signal and the enable signal. A power regulation system as described in claim 1, wherein when the power instruction is less than or equal to a power threshold, the driving circuit controls the plurality of switch elements to stop operating. A power regulation system as described in claim 1, wherein when the power command is less than or equal to a power threshold, the driving circuit blocks the pulse width modulation signal to control the plurality of switch elements to stop operating. A power regulation system as described in any one of claim 2-3, wherein the power regulation system is electrically connected to a power supply system; and an energy management unit outputs the power instruction according to a main electrical parameter of the power supply system. A power regulation system as described in claim 4, wherein when the main electrical parameter of the power supply system is within a set parameter range, the power instruction output by the energy management unit is a first type of power instruction, wherein the first type of power instruction is less than the power threshold; when the main electrical parameter of the power supply system is outside the set parameter range, the power instruction output by the energy management unit is a second type of power instruction, wherein the second type of power instruction is greater than the power threshold. A power regulation system as described in claim 5, wherein the first type of power instruction and the second type of power instruction are discontinuous, and when the main power parameter of the power supply system moves from within the setting parameter range to outside the setting parameter range, the power instruction output by the energy management unit jumps from the first type of power instruction to the second type of power instruction. A power regulation system as described in any one of claim items 2-3, wherein the power regulation system is electrically connected between an energy storage unit and a power supply system, and an energy management unit outputs the power instruction according to a main electrical parameter of the power supply system and a charge state of the energy storage unit. A power regulation system as described in claim 7, wherein when the main electrical parameter of the power supply system is within a set parameter range and the state of charge is within a set charge range, the power instruction output by the energy management unit is a first type of power instruction, wherein the first type of power instruction is less than or equal to the power threshold; when the main electrical parameter of the power supply system is outside the set parameter range or the state of charge is outside the set charge range, the power instruction output by the energy management unit is a second type of power instruction, wherein the second type of power instruction is greater than the power threshold. A power regulation system as described in claim 8, wherein the first type of power instruction is discontinuous with the second type of power instruction, and when the main power parameter of the power supply system moves from within the set parameter range to outside the set parameter range or the state of charge moves from within the set charge range to outside the set charge range, the power instruction output by the energy management unit jumps from the first type of power instruction to the second type of power instruction. A power regulation system as described in any one of claim 2-3, wherein the controller comprises: an enable unit for receiving the power command and comparing the power command with the power threshold to generate the enable signal; and a control unit for receiving the enable signal and the plurality of conversion parameters and generating the pulse width modulation signal according to the enable signal and the plurality of conversion parameters. A power regulation system as described in claim 1, wherein when the power instruction is less than or equal to a power threshold, the enable signal is a set level, and the drive circuit blocks the pulse width modulation signal to control the plurality of switch elements to stop operating; when the power instruction is greater than the power threshold, the enable signal is not the set level, and the drive circuit controls the operation of the plurality of switch elements according to the pulse width modulation signal, so that the output power of the at least one converter is adjusted according to the power instruction. A power regulation system as described in claim 1, wherein the number of the at least one converter of the power regulation system is N, and the N converters are connected in parallel; the controller is used to output N pulse width modulation signals according to the plurality of conversion parameters, output at least one enable signal according to the power command of the power regulation system, and output each pulse width modulation signal and each enable signal to the driving circuit of the corresponding converter, wherein N is a positive integer. A power regulation system as described in claim 12, wherein the controller compares the power command with N power thresholds to generate N enable signals; wherein the kth power threshold is less than the k+1th power threshold, and k is an integer greater than 1 and less than N; when the power command is less than or equal to the k+1th power threshold and greater than the kth power threshold, N-k enable signals among the N enable signals are a set level, and the remaining k enable signals are not the set level; and N-k drive circuits respectively receive the N-k enable signals with the set level to block the received pulse width modulation signal. A power regulation system as described in claim 1, wherein the power regulation system further comprises a filter, the filter comprising: a filter inductor electrically connected between the at least one converter and a power supply system, a filter capacitor and a damping resistor connected in series, one end of which is electrically connected to the filter inductor and the power supply system, and a bypass switch connected in parallel to the damping resistor. A power regulation system as described in claim 14, wherein the number of bypass switches to be closed is determined based on the strength of the power supply system. An energy storage device electrically connected to a power supply system comprises: an energy storage unit; and at least one power regulation system as described in claim 1, wherein the at least one power regulation system is electrically connected between the energy storage unit and the power supply system. A control method for a power regulation system, the power regulation system comprising at least one converter, a detection circuit and a controller, the at least one converter comprising a plurality of switch elements and a drive circuit, the drive circuit being electrically connected to the plurality of switch elements, wherein the control method comprises: (a) obtaining a plurality of conversion parameters of the at least one converter and a power instruction of the power regulation system; (b) generating a pulse width modulation signal according to the plurality of conversion parameters, and generating an enable signal according to the power instruction; and (c) controlling the operating state of the plurality of switch elements according to the pulse width modulation signal and the enable signal. The control method as described in claim 17, wherein in step (c), when the power command is less than or equal to a power threshold, the plurality of switch elements are controlled to stop operating. A control method as described in claim 17, wherein in step (b), when the power instruction is less than or equal to a power threshold, the enable signal is a set level, and when the power instruction is greater than the power threshold, the enable signal is not the set level; in step (c), when the enable signal is the set level, the pulse width modulation signal is blocked to control the plurality of switch elements to stop operating, and when the enable signal is not the set level, the operation of the plurality of switch elements is controlled according to the pulse width modulation signal, so that the output power of the at least one converter is adjusted according to the power instruction. A control method as described in claim 17, wherein the power regulation system is electrically connected to a power supply system, wherein in step (a), when a main electrical parameter of the power supply system is within a set parameter range, the power command is a first type of power command, wherein the first type of power command is less than or equal to a power threshold; when the main electrical parameter of the power supply system is outside the set parameter range, the power command is a second type of power command, wherein the second type of power command is greater than the power threshold. A control method as described in claim 20, wherein the first type of power command and the second type of power command are discontinuous, and when the main power parameter of the power supply system moves from within the setting parameter range to outside the setting parameter range, the power command jumps from the first type of power command to the second type of power command. A control method as described in claim 17, wherein the power regulation system is electrically connected between an energy storage unit and a power supply system, wherein in step (a), when a main electrical parameter of the power supply system is within a set parameter range and a state of charge of the energy storage unit is within a set charge range, the power command is a first type of power command, wherein the first type of power command is less than or equal to a power threshold; when the main electrical parameter is outside the set parameter range or the state of charge is outside the set charge range, the power command is a second type of power command, wherein the second type of power command is greater than the power threshold. A control method as described in claim 22, wherein the first type of power command is discontinuous with the second type of power command, and when the main power parameter moves from within the set parameter range to outside the set parameter range or the state of charge moves from within the set charge range to outside the set charge range, the power command jumps from the first type of power command to the second type of power command.

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