Power control device and power control system

Abstract

The invention provides a power control device and a power control system. The power control device comprises a controller, a signal isolation circuit and a driving voltage generation circuit. The controller is used for outputting a PWM signal with a set duty ratio, and the signal isolation circuit is used for carrying out isolation processing on the PWM signal so as to output the isolated PWM signal. The driving voltage generation circuit is electrically connected between the signal isolation circuit and the solid-state relay, the solid-state relay is electrically connected between the photovoltaic power generation equipment and the load, and the driving voltage generation circuit is used for generating driving voltage to the solid-state relay according to the isolated PWM signal so as to control the solid-state relay to be switched on or switched off. The solid-state relay can be controlled through the PWM signal, and the working power of the load can be adjusted by changing the duty ratio of the PWM signal output by the controller.

Description

Technical Field

[0001] The present application relates to the field of electronic technology, and in particular to a power control device and a power control system. Background Art

[0002] Photovoltaic power generation equipment can convert solar energy into electrical energy, and photovoltaic power generation equipment can provide photovoltaic surplus power to the load. At present, in order to improve the utilization rate of photovoltaic power and realize the efficient and comprehensive utilization of energy, how to design a power control device that accurately controls the load power is one of the problems to be solved. Summary of the invention

[0003] In view of the above, the present application provides a power control device and a power control system, which can control the power of a load and have a simple structure.

[0004] The first aspect of the present application provides a power control device, the power control device comprising: a controller, a signal isolation circuit and a drive voltage generating circuit. The controller is configured to output a PWM signal with a set duty cycle. The signal isolation circuit is electrically connected to the controller, and the signal isolation circuit is used to isolate and process the PWM signal to output the isolated PWM signal. The drive voltage generating circuit is electrically connected between the signal isolation circuit and the solid-state relay, and the solid-state relay is electrically connected between the photovoltaic power generation device and the load. The drive voltage generating circuit is used to generate a drive voltage to the solid-state relay according to the isolated PWM signal, and the drive voltage can control the solid-state relay to be turned on or off.

[0005] The power control device of the present application is used to isolate and process the PWM signal output by the controller through a signal isolation circuit, and to control the on or off of the solid-state relay through a driving voltage generation circuit. Therefore, the present application can control the solid-state relay through a PWM signal, and can adjust the load working power by changing the duty cycle of the PWM signal output by the controller. It can be understood that in some examples, the present application can adjust the heating power of the water heater by adjusting the duty cycle of the PWM signal output by the controller.

[0006] As an optional implementation, the controller includes a signal output end; the signal isolation circuit includes a photocoupler and a first switch tube, the photocoupler includes a light-emitting diode and a phototransistor; the first end of the first switch tube is electrically connected to the signal output end of the controller to receive the PWM signal output by the signal output end, the second end of the first switch tube is connected to the first ground end, the third end of the first switch tube is electrically connected to the cathode of the light-emitting diode, the anode of the light-emitting diode is electrically connected to the first power supply, the emitter of the phototransistor is connected to the second ground end, the collector of the phototransistor is electrically connected to the second power supply, and the emitter of the phototransistor is also electrically connected to the drive voltage generating circuit.

[0007] As an optional implementation, the signal isolation circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, and a first capacitor. The first end of the first switch tube is electrically connected to the signal output end of the controller through the first resistor, the first end of the first switch tube is also connected to the first ground end through the second resistor, the first end of the first switch tube is also connected to the first ground end through the first capacitor, the second end of the first switch tube is connected to the first ground end, the third end of the first switch tube is electrically connected to the cathode of the light-emitting diode, the anode of the light-emitting diode is electrically connected to the first power supply through the third resistor, the emitter of the phototransistor is connected to the second ground end, the collector of the phototransistor is electrically connected to the second power supply through the fourth resistor, and the collector of the phototransistor is also electrically connected to the driving voltage generating circuit through the fifth resistor.

[0008] As an optional implementation, the driving voltage generating circuit includes a second switching tube, and the solid-state relay includes a coil and a switch; the first end of the second switching tube is electrically connected to the collector of the phototransistor and the second power supply, the second end of the second switching tube is connected to the second ground terminal and the second end of the coil, the third end of the second switching tube is electrically connected to the third power supply, the third end of the second switching tube is electrically connected to the first end of the coil, and the switch is electrically connected between the photovoltaic power generation equipment and the load.

[0009] As an optional implementation, the driving voltage generating circuit also includes a sixth resistor, a seventh resistor, an eighth resistor and a second capacitor; the first end of the second switch tube is connected to the second ground terminal through the sixth resistor, the first end of the second switch tube is also connected to the second ground terminal through the second capacitor, the second end of the second switch tube is electrically connected to the second ground terminal, the third end of the second switch tube is connected to the third power supply through the seventh resistor, and the third end of the second switch tube is also electrically connected to the first end of the coil through the eighth resistor.

[0010] As an optional implementation, in a first time period of a switching cycle, the controller is used to output a PWM signal having a first level state to control the first switch tube to turn on, so that the light-emitting diode of the photocoupler emits light, and the photosensitive transistor of the photocoupler turns on, so that the second switch tube is turned off, and the third power supply outputs a driving voltage to the coil of the solid-state relay to control the switch to close; in a second time period of the switching cycle, the controller is used to output a PWM signal having a second level state to control the first switch tube to turn off, the light-emitting diode of the photocoupler does not emit light, the photosensitive transistor of the photocoupler is turned off, the second power supply outputs a voltage signal to control the second switch tube to turn on, and the third power supply does not output a driving voltage to the coil to disconnect the switch.

[0011] As an optional implementation, the power control device also includes a first power supply isolation module; the first power supply is electrically connected to the first power supply isolation module, and the first power supply is isolated and processed by the first power supply isolation module to obtain a second power supply; wherein the first power supply is a system power supply and the second power supply is an isolated power supply.

[0012] As an optional implementation, the first ground terminal is electrically connected to the first power isolation module, and the first ground terminal is isolated by the first power isolation module to obtain the second ground terminal; wherein the first ground terminal is the system ground, and the second ground terminal is the isolation ground.

[0013] As an optional implementation, the power control device also includes a second power supply isolation module; the fourth power supply is electrically connected to the second power supply isolation module, and the fourth power supply is isolated and processed by the second power supply isolation module to obtain a third power supply; wherein the fourth power supply is a system power supply and the third power supply is an isolated power supply.

[0014] The second aspect of the present application also provides a power control system, which includes a solid-state relay and the power control device described above, the power control device is electrically connected to the solid-state relay, the solid-state relay is electrically connected between the photovoltaic power generation equipment and the load, and the power control device is used to control the conduction or shutdown of the solid-state relay.

[0015] It should be understood that the power control systems described in the second aspect provided above correspond to the power control devices of the first aspect provided above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding power control devices provided above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 This is an application scenario diagram of a power control system provided in an embodiment of the present application.

[0018] Figure 2 It is a schematic diagram of a power control device provided in an embodiment of the present application.

[0019] Figure 3 This is another schematic diagram of a power control device provided in an embodiment of the present application.

[0020] Figure 4 It is a schematic diagram of the first power isolation module provided in an embodiment of the present application.

[0021] Figure 5 It is a schematic diagram of a second power isolation module provided in an embodiment of the present application. DETAILED DESCRIPTION

[0022] In the embodiments of the present application, the words "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying order. For example, the first application, the second application, etc. are used to distinguish different applications, rather than to describe a specific order of applications. The features defined as "first" or "second" may explicitly or implicitly include one or more of the features.

[0023] Photovoltaic power generation equipment can convert solar energy into electrical energy, and photovoltaic power generation equipment can provide photovoltaic surplus power to the load. In order to improve the utilization rate of photovoltaic power and achieve efficient and comprehensive utilization of energy, how to design a power control device that accurately controls the load power is one of the problems to be solved.

[0024] To this end, the present application provides a power control device and a power control system, which can accurately adjust the working power of the load, have a simple structure, and can improve the utilization rate of photovoltaic power.

[0025] See also Figure 1 , is an application scenario diagram of a power control system 300 provided by an embodiment of the present application. Figure 1 As shown, the power control system 300 in this embodiment includes a power control device 100 and a solid-state relay 200 .

[0026] The solid-state relay 200 is electrically connected between the photovoltaic power generation device 400 and the load 500. Specifically, the neutral line N of the load 500 is connected to the photovoltaic power generation device 400, and the live line L of the load 500 is connected to the photovoltaic power generation device 400 through the solid-state relay 200. Therefore, the power control system 300 of the present application can realize the control of the power of the load 500 by controlling the on and off of the solid-state relay 200.

[0027] It can be understood that in this embodiment, the power control device 100 can be electrically connected to the solid-state relay 200, and the power control device 100 can be used to control the solid-state relay 200 to be turned on and to control the solid-state relay 200 to be turned off. In other words, when the power control device 100 controls the solid-state relay 200 to be turned on, the photovoltaic power generation device 400 can supply power to the load 500. When the power control device 100 controls the solid-state relay 200 to be turned off, the photovoltaic power generation device 400 is disconnected from the load 500.

[0028] In a possible example, the load 500 may be a water heater. The power control device 100 controls the state of the solid-state relay 200 to control the heating power of the water heater.

[0029] See also Figure 2 , is a schematic diagram of a power control device 100 provided in accordance with an embodiment of the present application.

[0030] The power control device 100 includes a signal processing circuit 10 and a controller 20. The signal processing circuit 10 is electrically connected between the controller 20 and the solid-state relay 200.

[0031] In this embodiment, the power control device 100 communicates with the photovoltaic power generation device 400 through a communication bus, and the controller 20 can obtain the photovoltaic surplus power of the photovoltaic power generation device 400. The controller 20 can output a corresponding pulse width modulation (PWM) signal to the signal processing circuit 10 according to the photovoltaic surplus power of the photovoltaic power generation device 400. The signal processing circuit 10 can be used to process the PWM signal and generate a PWM drive voltage to the solid-state relay 200 to control the solid-state relay 200 to conduct. It can be understood that in a possible example, the controller 20 can be a micro controller unit (MCU).

[0032] The signal processing circuit 10 may include a signal isolation circuit 12 and a driving voltage generation circuit 14 .

[0033] The signal isolation circuit 12 is electrically connected to the signal output terminal of the controller 20 , the driving voltage generating circuit 14 is electrically connected between the signal isolation circuit 12 and the solid-state relay 200 , and the live wire L of the load 500 is connected to the photovoltaic power generation device 400 through the solid-state relay 200 .

[0034] The signal output terminal of the controller 20 can be used to output a PWM signal.

[0035] The signal isolation circuit 12 can receive the PWM signal, and the PWM signal is output to the driving voltage generating circuit 14 after being isolated by the signal isolation circuit 12. Based on such a design, the present application can avoid interference between the input PWM signal and the output signal.

[0036] Next, the driving voltage generating circuit 14 may receive the PWM signal after signal isolation, generate a PWM driving voltage, and output a synchronized PWM driving voltage to the solid-state relay 200 .

[0037] The signal processing circuit 10 of the present application isolates the input PWM signal through the signal isolation circuit 12, and then outputs it to the driving voltage generating circuit 14. The driving voltage generating circuit 14 generates a PWM driving voltage and outputs it to the solid-state relay 200 to control the solid-state relay 200 to conduct. Therefore, the present application can adjust the duty cycle of the output PWM signal through the controller 20 to adjust the working power of the load 500.

[0038] See also Figure 3 , which is a circuit diagram of a power control device 100 provided in one embodiment of the present application.

[0039] like Figure 3 As shown, the signal isolation circuit 12 may include an optocoupler U1, a first switch tube Q1, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a capacitor C1 and a capacitor C2. The driving voltage generating circuit 14 may include a second switch tube Q2, a resistor R7 and a resistor R8.

[0040] The photocoupler U1 includes a light emitting diode and a phototransistor.

[0041] The first switch tube Q1 includes a first end, a second end and a third end.

[0042] The first end of the first switch tube Q1 is electrically connected to the signal output terminal O1 of the controller 20 through the resistor R1, the first end of the first switch tube Q1 is also electrically connected to the first end of the resistor R2 and the first end of the capacitor C1, the second end of the resistor R2 is connected to the first ground terminal GND1, the second end of the resistor R2 is electrically connected to the second end of the capacitor C1, the second end of the first switch tube Q1 is electrically connected to the second end of the resistor R2, the second end of the capacitor C1 and the first ground terminal GND1. The third end of the first switch tube Q1 is electrically connected to the cathode of the light emitting diode of the photocoupler U1.

[0043] The first end of the first switch tube Q1 can be used as the control end of the first switch tube Q1 , that is, the signal output end O1 of the controller 20 outputs a PWM signal to the control end of the first switch tube Q1 to control the on or off of the first switch tube Q1 .

[0044] The anode of the light-emitting diode of the photocoupler U1 is electrically connected to the first power supply V1 through the resistor R3, the collector of the phototransistor of the photocoupler U1 is electrically connected to the second power supply V2 through the resistor R4, the collector of the phototransistor of the photocoupler U1 is electrically connected to the driving voltage generating circuit 14, the first end of the resistor R6 and the first end of the capacitor C2 through the resistor R5, the emitter of the phototransistor of the photocoupler U1 is connected to the second ground terminal GND2, and the emitter of the phototransistor of the photocoupler U1 is electrically connected to the second end of the resistor R6 and the second end of the capacitor C2.

[0045] In some optional implementations, the first switch tube Q1 can be any one of a metal oxide semiconductor field effect transistor (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET), an insulated gate bipolar transistor (Insulated Gate Bipolar Transistor, IGBT), a bipolar power transistor (bipolar power transistor) or a wide bandgap semiconductor field effect transistor.

[0046] In one example, the solid state relay 200 may include a switch S1 and a coil L1 .

[0047] The first end of the second switch tube Q2 is electrically connected to the collector of the phototransistor of the photocoupler U1 through the resistor R5, the second end of the second switch tube Q2 is electrically connected to the second ground terminal GND2, the third end of the second switch tube Q2 is electrically connected to the third power supply V3 through the resistor R7, the third end of the second switch tube Q2 is electrically connected to the first end of the coil L1 of the solid-state relay 200 through the resistor R8, and the second end of the second switch tube Q2 is electrically connected to the second end of the coil L1.

[0048] The first end of the second switch tube Q2 can be used as the control end of the second switch tube Q2, that is, the PWM signal output by the photocoupler U1 to the control end of the second switch tube Q2 can control the on or off of the second switch tube Q2.

[0049] A first end of the switch S1 is electrically connected to the load 500 through a live line L, and a second end of the switch S1 is electrically connected to the photovoltaic power generation device 400 through the live line L.

[0050] In some optional implementations, the second switch tube Q2 can be any one of a metal oxide semiconductor field effect transistor (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET), an insulated gate bipolar transistor (Insulated Gate Bipolar Transistor, IGBT), a bipolar power transistor (bipolar power transistor) or a wide bandgap semiconductor field effect transistor.

[0051] It can be understood that in the present application, the photocoupler U1 can be a device with an insulation withstand voltage of 5 kV, which can protect the controller 20.

[0052] It can be understood that in the present application, the solid-state relay 200 can support devices with 12V input and 40~380V output, and the turn-on and turn-off times of the solid-state relay 200 are both less than 1ms.

[0053] It can be understood that the first power supply V1 is the system power supply, and the first ground terminal GND1 is the system ground. The second power supply V2 is the isolated power supply, and the second ground terminal GND2 is the isolated ground. The system power supply and the system ground can be obtained through the power isolation module to obtain the isolated power supply and the isolated ground respectively.

[0054] like Figure 4 As shown, the first power supply V1 and the first ground terminal GND1 are both electrically connected to the first power isolation module 30. After being isolated by the first power isolation module 30, the first power supply V1 and the first ground terminal GND1 obtain an isolated second power supply V2 and an isolated second ground terminal GND2 respectively.

[0055] As an example of the present application, the first power source V1 is used to output a voltage of 3.3V. The second power source V2 is used to output a voltage of 3.3V.

[0056] The third power supply V3 is an isolated power supply, and the fourth power supply V4 is a system power supply.

[0057] like Figure 5 As shown, the fourth power supply V4 and the first ground terminal GND1 are both electrically connected to the second power isolation module 40. After being isolated by the second power isolation module 40, the fourth power supply V4 and the first ground terminal GND1 obtain an isolated third power supply V3 and an isolated second ground terminal GND2.

[0058] As an example of the present application, the third power source V3 is used to output a 12V voltage. The fourth power source V4 is used to output a 12V voltage.

[0059] It is understood that in the present application, the fourth power source V4 can be converted by a voltage conversion circuit to obtain the first power source V1. As a possible example, the power conversion circuit 50 can be a DC-DC voltage conversion circuit. The power conversion circuit 50 can convert the 12V DC voltage output by the fourth power source V4 into a 3.3V DC voltage.

[0060] The following will be combined Figure 3 The illustrated embodiment introduces in detail the working principle of the power control device 100 of the present application.

[0061] During operation, the signal output terminal O1 of the controller 20 outputs a PWM signal having a first duty cycle. For example, the first duty cycle is 0.7.

[0062] Assuming that a switching cycle is 1ms, in the time period T1 of the switching cycle (for example, the time period of 0~0.7ms), the PWM signal controls the first switch tube Q1 to turn on, so that the light-emitting diode of the photocoupler U1 emits light, and the phototransistor of the photocoupler U1 is turned on. Since the phototransistor of the photocoupler U1 and the light-emitting diode are turned on and off at the same frequency, the signal output by the photocoupler U1 is also a PWM signal, and the duty cycle of the PWM signal output by the photocoupler U1 is the same as the duty cycle of the PWM signal output by the controller 20. At this time, the second switch tube Q2 is turned off, and the third power supply V3 outputs a voltage to the coil L1 of the solid-state relay 200, that is, the coil L1 of the solid-state relay 200 begins to be energized, thereby controlling the switch S1 to close, so that the live wire L of the load 500 is connected to the photovoltaic power generation device 400. Therefore, in the time period of 0~0.7ms of the switching cycle, the solid-state relay 200 turns on the live wire power supply of the load 500, and the photovoltaic power generation device 400 provides working energy for the load 500.

[0063] In the time period T2 of the switching cycle (e.g., the time period of 0.7-1ms), the PWM signal controls the first switch tube Q1 to turn off, the light-emitting diode of the photocoupler U1 does not emit light, the phototransistor of the photocoupler U1 is turned off, and the voltage signal output by the second power supply V2 controls the second switch tube Q2 to turn on. At this time, the coil L1 of the solid-state relay 200 is not energized, that is, the switch S1 of the solid-state relay 200 is turned off. Therefore, in the time period of 0.7-1ms of the switching cycle, the solid-state relay 200 turns off the live wire power supply of the load 500, that is, the photovoltaic power generation device 400 does not provide energy to the load 500.

[0064] The time period T1 and the time period T2 constitute a switching cycle.

[0065] In one scenario, if the photovoltaic surplus power of the photovoltaic power generation device increases, the controller 20 can increase the duty cycle of the output PWM signal. That is, the signal output terminal O1 of the controller 20 outputs a PWM signal with a second duty cycle. For example, the second duty cycle is 0.8.

[0066] Assuming that a switching cycle is 1ms, in the time period T3 of the switching cycle (for example, the time period of 0~0.8ms), the PWM signal controls the first switch tube Q1 to turn on, so that the light-emitting diode of the photocoupler U1 emits light, the photosensitive transistor of the photocoupler U1 is turned on, the second switch tube Q2 is turned off, and the third power supply V3 outputs a voltage to the coil L1 of the solid-state relay 200, that is, the coil L1 of the solid-state relay 200 begins to be energized, thereby controlling the switch S1 to close, and the solid-state relay 200 turns on the live power supply of the load 500. Therefore, in the time period of 0~0.8ms of the switching cycle, the photovoltaic power generation device 400 provides working energy for the load 500.

[0067] In the time period T4 of the switching cycle (e.g., the time period of 0.8-1ms), the PWM signal controls the first switch tube Q1 to turn off, the light-emitting diode of the photocoupler U1 does not emit light, and the photosensitive transistor of the photocoupler U1 turns off, thereby turning on the second switch tube Q2. At this time, the coil L1 of the solid-state relay 200 is not energized, that is, the switch S1 of the solid-state relay 200 is turned off. Therefore, in the time period of 0.8-1ms of the switching cycle, the solid-state relay 200 turns off the live wire power supply of the load 500, that is, the photovoltaic power generation device 400 does not provide energy to the load 500.

[0068] The time period T3 and the time period T4 constitute a switching cycle.

[0069] In another scenario, if the photovoltaic surplus power of the photovoltaic power generation equipment decreases or due to the dispatch of the power grid, the controller 20 can reduce the duty cycle of the output PWM signal. That is, the signal output terminal O1 of the controller 20 outputs a PWM signal with a third duty cycle. For example, the third duty cycle is 0.6.

[0070] Assuming that a switching cycle is 1ms, in the time period T5 of the switching cycle (for example, the time period of 0~0.6ms), the PWM signal controls the first switch tube Q1 to turn on, so that the light-emitting diode of the photocoupler U1 emits light, the phototransistor of the photocoupler U1 is turned on, the second switch tube Q2 is turned off, and the third power supply V3 outputs a voltage to the coil L1 of the solid-state relay 200, that is, the coil L1 of the solid-state relay 200 begins to be energized, thereby controlling the switch S1 to close, and the solid-state relay 200 turns on the live power supply of the load 500. Therefore, in the time period of 0~0.6s of the switching cycle, the photovoltaic power generation device 400 provides working energy for the load 500.

[0071] In the time period T6 of the switching cycle (for example, the time period of 0.6~1ms), the PWM signal controls the first switch tube Q1 to turn off, the light-emitting diode of the photocoupler U1 does not emit light, and the photosensitive transistor of the photocoupler U1 turns off, thereby turning on the second switch tube Q2. At this time, the coil L1 of the solid-state relay 200 is not energized, that is, the switch S1 of the solid-state relay 200 is turned off. Therefore, in the time period of 0.6~1ms of the switching cycle, the solid-state relay 200 turns off the live power supply of the load 500, that is, the photovoltaic power generation device 400 does not provide energy to the load 500.

[0072] The time period T5 and the time period T6 constitute a switching cycle.

[0073] From the above, it can be seen that the power control system of the present application uses a solid-state relay to control the conduction or shutdown of the live power supply of the load, continuously controls the opening and disconnection of the solid-state relay at a certain frequency, and can adjust the conduction time of each switching cycle, thereby changing the working power of the load.

[0074] It can be understood that in the present application, the relationship between the duty cycle D1 of the PWM signal output by the controller 20 and the actual working power P1 of the load 500 satisfies the following formula (1): P1=D1×P2 (1) Wherein, P2 is the rated power of the load 500. The frequency of the PWM signal output by the controller 20 may be 50 Hz, and the duty cycle range of the PWM signal output by the controller 20 may be 0-100%.

[0075] From the above formula (1), it can be known that the controller 20 can accurately adjust the working power of the load 500 by adjusting the duty cycle of the output PWM signal. It can be understood that in some examples, the load can be a water heater, and the present application can adjust the heating power of the water heater by adjusting the duty cycle of the output PWM signal by the controller 20.

[0076] Based on the above-mentioned embodiments, in the power control device 100 provided in the present application, the controller 20 communicates with the inverter in the photovoltaic power generation equipment to obtain the photovoltaic surplus power, and adjusts the duty cycle of the output PWM signal according to the photovoltaic surplus power or the scheduling of the power grid to adjust the working power of the load.

[0077] It is obvious to those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and that the present application can be implemented in other specific forms without departing from the spirit or basic features of the present application. Therefore, as long as they are within the scope of the essence and spirit of the present application, appropriate changes and modifications made to the above embodiments should fall within the scope of protection claimed in the present application.

Claims

1. A power control device, characterized in that: The power control device comprises: a controller, a signal isolation circuit and a driving voltage generating circuit; The controller is configured to output a PWM signal having a set duty cycle; The signal isolation circuit is electrically connected to the controller, and the signal isolation circuit is configured to perform isolation processing on the PWM signal to output an isolated PWM signal; The driving voltage generating circuit is electrically connected between the signal isolation circuit and the solid-state relay, the solid-state relay is electrically connected between the photovoltaic power generation equipment and the load, the driving voltage generating circuit is configured to generate a driving voltage for the solid-state relay according to the isolated PWM signal, and the driving voltage is configured to control the solid-state relay to be turned on or off.

2. The power control device according to claim 1, characterized in that: The controller includes a signal output terminal; The signal isolation circuit includes a photoelectric coupler and a first switch tube, and the photoelectric coupler includes a light emitting diode and a phototransistor; The first end of the first switch tube is electrically connected to the signal output end of the controller to receive the PWM signal output by the signal output end, the second end of the first switch tube is connected to the first ground end, the third end of the first switch tube is electrically connected to the cathode of the light-emitting diode, the anode of the light-emitting diode is electrically connected to the first power supply, the emitter of the phototransistor is connected to the second ground end, the collector of the phototransistor is electrically connected to the second power supply, and the emitter of the phototransistor is also electrically connected to the driving voltage generating circuit.

3. The power control device according to claim 2, characterized in that: The signal isolation circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, and a first capacitor. The first end of the first switch tube is electrically connected to the signal output end of the controller through the first resistor, the first end of the first switch tube is also connected to the first ground end through the second resistor, the first end of the first switch tube is also connected to the first ground end through the first capacitor, the second end of the first switch tube is connected to the first ground end, the third end of the first switch tube is electrically connected to the cathode of the light-emitting diode, the anode of the light-emitting diode is electrically connected to the first power supply through the third resistor, the emitter of the phototransistor is connected to the second ground end, the collector of the phototransistor is electrically connected to the second power supply through the fourth resistor, and the collector of the phototransistor is also electrically connected to the driving voltage generating circuit through the fifth resistor.

4. The power control device according to claim 2, characterized in that: The driving voltage generating circuit includes a second switch tube, and the solid-state relay includes a coil and a switch; The first end of the second switch tube is electrically connected to the collector of the phototransistor and the second power supply, the second end of the second switch tube is connected to the second ground end and the second end of the coil, the third end of the second switch tube is electrically connected to the third power supply, the third end of the second switch tube is electrically connected to the first end of the coil, and the switch is electrically connected between the photovoltaic power generation equipment and the load.

5. The power control device according to claim 4, characterized in that: The driving voltage generating circuit also includes a sixth resistor, a seventh resistor, an eighth resistor and a second capacitor; the first end of the second switch tube is connected to the second ground end through the sixth resistor, the first end of the second switch tube is also connected to the second ground end through the second capacitor, the second end of the second switch tube is electrically connected to the second ground end, the third end of the second switch tube is connected to the third power supply through the seventh resistor, and the third end of the second switch tube is also electrically connected to the first end of the coil through the eighth resistor.

6. The power control device according to claim 4, characterized in that: In a first time period of a switching cycle, the controller is configured to output a PWM signal having a first level state to control the first switch tube to be turned on, so that the light-emitting diode of the photocoupler emits light, and the phototransistor of the photocoupler is turned on, so that the second switch tube is turned off, and the third power supply outputs a driving voltage to the coil of the solid-state relay to control the switch to be closed; In the second time period of the switching cycle, the controller is configured to output a PWM signal with a second level state to control the first switch tube to be turned off, the light-emitting diode of the optocoupler does not emit light, the phototransistor of the optocoupler is turned off, the second power supply outputs a voltage signal to control the second switch tube to be turned on, and the third power supply does not output a driving voltage to the coil to disconnect the switch.

7. The power control device according to claim 4, characterized in that: The power control device also includes a first power isolation module; The first power supply is electrically connected to the first power supply isolation module, and the first power supply is isolated by the first power supply isolation module to obtain the second power supply; The first power supply is a system power supply, and the second power supply is an isolated power supply.

8. The power control device according to claim 7, characterized in that: The first grounding terminal is electrically connected to the first power isolation module, and the first grounding terminal is isolated by the first power isolation module to obtain the second grounding terminal; The first ground terminal is a system ground, and the second ground terminal is an isolation ground.

9. The power control device according to claim 4, characterized in that: The power control device also includes a second power isolation module; The fourth power supply is electrically connected to the second power supply isolation module, and the fourth power supply is isolated by the second power supply isolation module to obtain the third power supply; Wherein, the fourth power supply is a system power supply, and the third power supply is an isolated power supply.

10. A power control system, characterized in that: The power control system includes a solid-state relay and a power control device as described in any one of claims 1 to 9, wherein the power control device is electrically connected to the solid-state relay, the solid-state relay is electrically connected between a photovoltaic power generation device and a load, and the power control device is configured to control the on or off of the solid-state relay.

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