Power supply circuit and power supply system

Abstract

The utility model discloses a power supply circuit and a power supply system, and is applied to the power supply system, the power supply system is used for supplying power to a load, the power supply circuit comprises a switch switching circuit, the first input end of the switch switching circuit is connected with commercial power; the input end of the rectifying circuit is connected with the output end of the switch switching circuit; the driving circuit is connected with the control end of the switch switching circuit; the auxiliary power supply is connected with the output end of the rectifying circuit; when the output power of the auxiliary power supply is smaller than or equal to a power threshold value, the driving circuit is used for driving the first input end of the switch switching circuit to be connected with the output end of the switch switching circuit, and the mains supply charges the auxiliary power supply through the rectifying circuit. The power supply circuit can avoid power-off restart of the auxiliary power supply, maintain operation of the power supply system and maintain reliable operation of the load. In addition, the number of times of power-off restart of the auxiliary power supply is reduced, damage of components in the circuit can be reduced, and the service life of the circuit is prolonged.

Description

Technical Field

[0001] The present application relates to the technical field of power supplies, and in particular to a power supply circuit and a power supply system. Background Art

[0002] Photovoltaic power generation is a technology that uses the photovoltaic effect of semiconductor interfaces to directly convert light energy into electrical energy. The photovoltaic power supply system includes solar panels, energy storage batteries, controllers and inverters, as well as multiple electronic components. Among them, components such as operational amplifiers, chips or relays require power to power them. The auxiliary power supply is the power supply in the power supply system that powers the above components.

[0003] In the prior art, the auxiliary power supply is usually supplied by a DC bus, and a solar panel or an energy storage battery is connected to the DC bus to supply power to the auxiliary power supply through the DC bus. However, the output power of the solar panel is affected by the light intensity and the area of ​​the panel. During the process of grid connection or power supply, the output power varies greatly, and the output power may drop instantly, causing the auxiliary power supply to be powered off and restarted. Frequent restart of the auxiliary power supply will affect the service life of the circuit, and when the output power of the auxiliary power supply is insufficient to maintain the operation of the power supply system, it will affect the reliable operation of the load. Utility Model Content

[0004] In view of the problems existing in the background technology, the purpose of the present application is to provide a power supply circuit and a power supply system.

[0005] To achieve the above-mentioned purpose, the present application provides a power supply circuit, which is applied to a power supply system, wherein the power supply system is used to supply power to a load, and the power supply circuit includes: a switching circuit, wherein a first input end of the switching circuit is connected to the mains; a rectifier circuit, wherein an input end of the rectifier circuit is connected to an output end of the switching circuit; a drive circuit, which is connected to a control end of the switching circuit; and an auxiliary power supply, which is connected to an output end of the rectifier circuit; when the output power of the auxiliary power supply is less than or equal to a power threshold, the drive circuit is used to drive the first input end of the switching circuit to be connected to the output end of the switching circuit, and the mains charges the auxiliary power supply through the rectifier circuit.

[0006] Wherein, when the output power of the auxiliary power supply is greater than the power threshold, the driving circuit is used to drive the first input end of the switch switching circuit and the output end of the switch switching circuit to disconnect.

[0007] Wherein, the switch switching circuit includes a relay and a coil, the first end and the eighth end of the relay are suspended, the second end and the seventh end of the relay serve as the output end of the switch switching circuit, the third end and the sixth end of the relay serve as the first input end of the switch switching circuit, the fourth end and the fifth end of the relay serve as the control end of the switch switching circuit, one end of the coil is connected to the fourth end of the relay, and the other end of the coil is connected to the fifth end of the relay.

[0008] The driving circuit includes a first resistor and a switch, the first end of the switch is grounded, the second end of the switch is connected to the fifth end of the relay, one end of the first resistor is connected to the fourth end of the relay, the other end of the first resistor receives a reference voltage, and the control end of the switch receives a control signal.

[0009] Wherein, when the output power of the auxiliary power supply is less than or equal to the power threshold, the control signal controls the switch to be disconnected, the second end and the third end of the relay are connected, and the seventh end and the sixth end of the relay are connected; when the output power of the auxiliary power supply is greater than the power threshold, the control signal controls the switch to be turned on, the second end and the first end of the relay are connected, and the seventh end and the eighth end of the relay are connected.

[0010] Wherein, the rectifier circuit includes a rectifier bridge, a second resistor, a third resistor, a first diode and a second diode, the first output end of the rectifier bridge is connected to the positive electrode of the first diode through the second resistor, the second output end of the rectifier bridge is connected to the negative electrode of the second diode through the third resistor, and the negative electrode of the first diode and the positive electrode of the second diode serve as the output end of the rectifier circuit.

[0011] In which, the rectifier circuit also includes a fourth resistor, a fifth resistor, a first capacitor and a second capacitor, the cathode of the first diode is connected to the anode of the second diode through the first capacitor and the second capacitor, the fourth resistor is connected in parallel with the first capacitor, and the fifth resistor is connected in parallel with the second capacitor.

[0012] Wherein, the power supply circuit also includes a third diode and a fourth diode, the first end of the load is connected to the positive end of the DC bus, the second end of the load is connected to the negative end of the DC bus, the positive end of the DC bus is connected to the positive electrode of the third diode, the negative electrode of the third diode is connected to the negative electrode of the first diode, the negative end of the DC bus is connected to the negative electrode of the fourth diode, and the positive electrode of the fourth diode is connected to the positive electrode of the second diode.

[0013] Wherein, the first end of the auxiliary power supply is connected to the cathode of the first diode, and the second end of the auxiliary power supply is connected to the anode of the second diode.

[0014] To achieve the above-mentioned purpose, the present application also provides a power supply system for supplying power to a load, the power supply system comprising a photovoltaic energy storage unit and a power supply circuit as described above, the photovoltaic energy storage unit being used to supply power to the load via a DC bus, the power supply circuit being connected to the DC bus and being used to charge an auxiliary power supply of the power supply circuit via the DC bus.

[0015] The embodiment of the present application provides a power supply circuit and a power supply system. When the output power of the auxiliary power supply is less than or equal to the power threshold, the switch switching circuit is controlled by the driving circuit to be turned on to connect the mains power, so that the mains power supplies power to the auxiliary power supply through the switch switching circuit and the rectifier circuit, avoiding the auxiliary power supply from powering off and restarting, maintaining the operation of the power supply system, and maintaining reliable operation of the load. In addition, the number of times the auxiliary power supply is powered off and restarted is reduced, which can reduce the damage to the components in the circuit and increase the service life of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 is a schematic diagram of a framework of an embodiment of a power supply circuit of the present application;

[0018] Figure 2 is a circuit diagram of an embodiment of a power supply circuit of the present application;

[0019] Figure 3 is a circuit diagram of another embodiment of the power supply circuit of the present application;

[0020] Figure 4 It is a schematic diagram of a framework of an embodiment of a power supply system of the present application. DETAILED DESCRIPTION

[0021] The present application is further described in detail below in conjunction with the accompanying drawings and examples. It is particularly noted that the following examples are only used to illustrate the present application, but are not intended to limit the scope of the present application. Similarly, the following examples are only some embodiments of the present application rather than all embodiments, and all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present application.

[0022] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0023] In the description of this application, it is necessary to explain that, unless otherwise clearly specified and limited, the terms "install", "set", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or connected through an intermediate medium. For ordinary technicians in this field, the above-mentioned specific meanings belonging to this application can be connected according to specific circumstances.

[0024] In the description of the present application, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradicting each other.

[0025] The term "and / or" in this article is only a description of the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the objects associated before and after are in an "or" relationship. In addition, "many" in this article means two or more than two. In addition, the term "at least one" in this article means any combination of at least two of any one or more of a plurality of, for example, including at least one of A, B, and C, can mean including any one or more elements selected from the set consisting of A, B, and C.

[0026] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0027] In the prior art, the output power of the solar panels of the photovoltaic power supply system is greatly affected by the light intensity. For example, in rainy weather, morning or night, the light intensity decreases, and the output power of the solar panels decreases. The auxiliary power supply requires a large power support at the moment of startup. If the energy storage battery is also underpowered, the DC bus voltage will be lowered at the moment of auxiliary power startup, causing the auxiliary power supply to be cut off again.

[0028] In addition, the output power of the photovoltaic power supply system is related to the area that can receive light energy or solar energy. During the power generation process of the photovoltaic power supply system, the power generated by the photovoltaic power supply system is supplied to the load first. If there is surplus power, it is connected to the grid and the excess power is stored in the energy storage battery. When connected to the grid, due to the small area of ​​the solar panel, the output power of the solar panel is prone to drop instantly, and it takes a certain amount of time for the energy storage battery to switch the charge and discharge current direction, so it cannot supply power to the auxiliary power supply in time, resulting in power failure of the auxiliary power supply.

[0029] After the auxiliary power supply is cut off, as the output power of the solar panel gradually increases, when it reaches the minimum operating power of the auxiliary power supply, the auxiliary power supply will restart. The auxiliary power supply requires a large power support at the moment of startup. If the solar panel or energy storage battery does not supply enough power, or the energy storage battery cannot supply power to the auxiliary power supply in time, the auxiliary power supply will restart frequently.

[0030] Based on the above problems, this application proposes a power supply circuit, see Figure 1 As shown, Figure 1 The power supply circuit 10 of this embodiment is used to realize supplying power to the auxiliary power supply 14 through the mains, and the power supply system is used to supply power to the load.

[0031] The power supply circuit 10 of this embodiment includes a switch switching circuit 11, a rectifier circuit 12, a drive circuit 13 and an auxiliary power supply 14. Among them, the first input end of the switch switching circuit 11 is connected to the mains, the input end of the rectifier circuit 12 is connected to the output end of the switch switching circuit 11, the drive circuit 13 is connected to the control end of the switch switching circuit 11, and the auxiliary power supply 14 is connected to the output end of the rectifier circuit 12.

[0032] The power supply system includes a plurality of components, among which components such as operational amplifiers, chips or relays require power supply, and the auxiliary power supply 14 is a power supply in the power supply system for supplying power to the above components.

[0033] The driving circuit 13 is used to control the connection and disconnection between the first input terminal and the output terminal of the switch circuit 11. The switch circuit 11 is connected to the mains, and the mains supplies power to the auxiliary power supply 14 through the switch circuit 11 and the rectifier circuit 12.

[0034] When the output power of the auxiliary power supply 14 is less than or equal to the power threshold, the driving circuit 13 is used to drive the first input end of the switch switching circuit 11 to be connected to the output end of the switch switching circuit 11, and the AC power charges the auxiliary power supply 14 through the rectifier circuit 12.

[0035] The power threshold is a preset power value, for example, the power threshold may be the minimum operating power of the auxiliary power supply 14. When the output power of the auxiliary power supply 14 is less than or equal to the power threshold, the auxiliary power supply 14 cannot operate normally; when the output power of the auxiliary power supply 14 is greater than the power threshold, the auxiliary power supply 14 operates normally. In other embodiments, the power threshold may also be greater than the minimum operating power of the auxiliary power supply 14.

[0036] When the output power of the auxiliary power supply 14 is greater than the power threshold, the driving circuit 13 is used to drive the first input end of the switch switching circuit 11 and the output end of the switch switching circuit 11 to be disconnected.

[0037] Among them, when the output power of the auxiliary power supply 14 is greater than the power threshold, the first input end of the switch switching circuit 11 and the output end of the switch switching circuit 11 are disconnected. At this time, the auxiliary power supply 14 is connected to the DC bus, and the solar panel or energy storage battery supplies power to the auxiliary power supply through the DC bus.

[0038] In this embodiment, when the output power of the auxiliary power supply 14 is less than or equal to the power threshold, the switch switching circuit 11 is controlled to be turned on by the driving circuit 13 to connect the mains, so that the mains supplies power to the auxiliary power supply 14 through the switch switching circuit 11 and the rectifier circuit 12, thereby avoiding the auxiliary power supply 14 from powering off and restarting, maintaining the operation of the power supply system, and maintaining the reliable operation of the load. In addition, the number of times the auxiliary power supply 14 is powered off and restarted is reduced, which can reduce the damage to the components in the circuit and increase the service life of the circuit.

[0039] See also Figure 2 As shown, Figure 2 FIG. 1 is a circuit diagram of an embodiment of a power supply circuit of the present application. Figure 1 and Figure 2As shown, the power supply circuit 10 of this embodiment includes a switch switching circuit 11, a rectifier circuit 12, a drive circuit 13 and an auxiliary power supply 14. Among them, the switch switching circuit 11 includes a relay 101 and a coil 102. The drive circuit 13 includes a first resistor 103 and a switch 104. The rectifier circuit 12 includes a rectifier bridge 105, a second resistor 106, a third resistor 108, a first diode 107 and a second diode 109. The auxiliary power supply 14 is connected to the output end of the rectifier circuit 12.

[0040] The switch switching circuit 11 includes a relay 101 and a coil 102, the first end and the eighth end of the relay 101 are suspended, the second end and the seventh end of the relay 101 serve as the output end of the switch switching circuit 11, the third end and the sixth end of the relay 101 serve as the first input end of the switch switching circuit 11, the fourth end and the fifth end of the relay 101 serve as the control end of the switch switching circuit 11, one end of the coil 102 is connected to the fourth end of the relay 101, and the other end of the coil 102 is connected to the fifth end of the relay 101.

[0041] The relay 101 includes a first state and a second state. When the relay 101 is in the first state, the second end of the relay 101 is connected to the third end, and the seventh end is connected to the sixth end. When the relay 101 is in the second state, the second end of the relay 101 is connected to the first end, and the seventh end is connected to the eighth end.

[0042] In this embodiment, the relay 101 is in the first state, the second end of the relay 101 is connected to the third end, and the seventh end of the relay 101 is connected to the sixth end.

[0043] The driving circuit 13 includes a first resistor 103 and a switch 104, wherein the first end of the switch 104 is grounded, the second end of the switch 104 is connected to the fifth end of the relay 101, one end of the first resistor 103 is connected to the fourth end of the relay 101, the other end of the first resistor 103 receives a reference voltage, and the control end of the switch 104 receives a control signal.

[0044] The reference voltage is used to form a loop for the drive circuit 13. For example, the other end of the first resistor 103 is connected to a voltage source, and the voltage source outputs a reference voltage to the drive circuit 13. The other end of the first resistor 103 can also be connected to a node in the circuit loop of the power supply circuit 10 or the power supply system.

[0045] The control end of the switch 104 can be connected to the control chip, and the control chip outputs a control signal to the control end of the switch 104. The control chip can be a control chip built into the power supply circuit 10, or it can be a controller of the power supply system. The switch 104 can be a MOS tube, a triode or a photocoupler. In this embodiment, the switch 104 is a MOS tube.

[0046] When the output power of the auxiliary power supply 14 is less than or equal to the power threshold, the control signal controls the switch 104 to be disconnected, the second end and the third end of the relay 101 are connected, and the seventh end and the sixth end of the relay 101 are connected; when the output power of the auxiliary power supply 14 is greater than the power threshold, the control signal controls the switch 104 to be turned on, the second end and the first end of the relay 101 are connected, and the seventh end and the eighth end of the relay 101 are connected.

[0047] When the output power of the auxiliary power supply 14 is less than or equal to the power threshold, the control signal controls the switch 104 to be disconnected, and the relay 101 is in the first state, that is, the second end and the third end of the relay 101 are connected, and the seventh end and the sixth end of the relay 101 are connected. At this time, the third end and the sixth end of the relay 101 serve as the first input end of the switch switching circuit 11, and the first input end of the switch switching circuit 11 is connected to the mains, and the mains supplies power to the auxiliary power supply 14 through the switch switching circuit 11 and the rectifier circuit 12.

[0048] When the output power of the auxiliary power supply 14 is greater than the power threshold, the control signal controls the switch 104 to be turned on, and the relay 101 is in the second state, that is, the second end of the relay 101 is connected to the first end, and the seventh end of the relay 101 is connected to the eighth end. Since the first end and the eighth end of the relay 101 are suspended, the rectifier circuit 12 is disconnected from the mains.

[0049] When the power supply circuit 10 is disconnected from the mains, the DC bus of the power supply system supplies power to the auxiliary power supply 14. The auxiliary power supply 14 is connected to the DC bus of the power supply system, a first end of the auxiliary power supply 14 is connected to the positive terminal of the DC bus, and a second end of the auxiliary power supply 14 is connected to the negative terminal of the DC bus.

[0050] The power supply system is used to supply power to the load, a first end of the load is connected to the positive end of the DC bus, and a second end of the load is connected to the negative end of the DC bus.

[0051] The rectifier circuit 12 includes a rectifier bridge 105, a second resistor 106, a third resistor 108, a first diode 107, and a second diode 109. The first output end of the rectifier bridge 105 is connected to the positive electrode of the first diode 107 through the second resistor 106, and the second output end of the rectifier bridge 105 is connected to the negative electrode of the second diode 109 through the third resistor 108. The negative electrode of the first diode 107 and the positive electrode of the second diode 109 serve as the output end of the rectifier circuit 12. The first end of the auxiliary power supply 14 is connected to the negative electrode of the first diode 107, and the second end of the auxiliary power supply 14 is connected to the positive electrode of the second diode 109.

[0052] The rectifier bridge 105 is used to convert AC power from the mains into DC power. The circuit unit composed of the second resistor 106 and the first diode 107 is used for rectification control. The second resistor 106 is used for voltage reduction and current limiting, and protects the first diode 107 through voltage division. The second diode 109 is used for overvoltage protection.

[0053] Optionally, the rectifier circuit 12 also includes a fourth resistor 110, a fifth resistor 111, a first capacitor 112 and a second capacitor 113, the cathode of the first diode 107 is connected to the anode of the second diode 109 through the first capacitor 112 and the second capacitor 113, the fourth resistor 110 is connected in parallel with the first capacitor 112, and the fifth resistor 111 is connected in parallel with the second capacitor 113.

[0054] The circuit unit consisting of the fourth resistor 110 and the first capacitor 112 or the circuit unit consisting of the fifth resistor 111 and the second capacitor 113 is used for filtering.

[0055] The power supply circuit 12 also includes a third diode 114 and a fourth diode 115. The positive terminal of the DC bus is connected to the positive electrode of the third diode 114, the negative electrode of the third diode 114 is connected to the negative electrode of the first diode 107, the negative terminal of the DC bus is connected to the negative electrode of the fourth diode 115, and the positive electrode of the fourth diode 115 is connected to the positive electrode of the second diode 109.

[0056] The power supply conditions of the power supply circuit 10 of this embodiment include the following three conditions:

[0057] (1) When only the mains power is supplied, the relay 101 is not energized, the coil 102 does not work, and the relay 101 is in the first state, that is, the second end of the relay 101 is connected to the third end, and the seventh end is connected to the sixth end. At this time, the mains power supplies the auxiliary power supply 14 through the rectifier circuit 12.

[0058] (2) When the output power of the auxiliary power supply 14 is greater than the power threshold value, the control signal controls the switch 104 to be turned on, the relay 101 is energized, the coil 102 is attracted, and the relay 101 is in the second state, that is, the second end of the relay 101 is connected to the first end, and the seventh end is connected to the eighth end. At this time, the solar panel or energy storage battery supplies power to the auxiliary power supply 14 through the DC bus.

[0059] (3) When the output power of the auxiliary power supply 14 is less than or equal to the power threshold value, the control signal controls the switch 104 to be disconnected, the relay 101 is not powered, the coil 102 does not work, the relay 101 is converted from the second state to the first state, and the AC power is supplied to the auxiliary power supply 14 through the rectifier circuit 12.

[0060] In this embodiment, relay 101 adopts a two-state relay, and the third end and the sixth end of relay 101 are normally closed contacts of relay 101. The third end and the sixth end of relay 101 serve as the first input end of the switch switching circuit 11, which is connected to the AC power supply. The relay 101 can be automatically reset by a control signal, so that relay 101 is in the first state. The AC power charges the auxiliary power supply 14 through the rectifier circuit 12, which can avoid power failure and restart of the auxiliary power supply 14, maintain the operation of the power supply system, maintain reliable operation of the load, and avoid the need for manual restart due to power supply interruption of the load.

[0061] See also Figure 3 As shown, Figure 3 FIG. 1 is a circuit diagram of another embodiment of the power supply circuit of the present application. Figure 3 As shown, different from Figure 2 In the embodiment shown, the relay 101 of the power supply circuit 10 of this embodiment is in the second state, the second end of the relay 101 is connected to the first end, and the seventh end is connected to the eighth end.

[0062] See also Figure 4 As shown, Figure 4 1 is a schematic diagram of a power supply system of the present application. The power supply system 40 of the present embodiment includes a power supply circuit 10 and a photovoltaic energy storage unit 20, the photovoltaic energy storage unit 20 is used to supply power to a load 50 via a DC bus, and the power supply circuit 10 is connected to the DC bus for charging an auxiliary power supply 14 of the power supply circuit 10 via the DC bus.

[0063] like Figure 1 and Figure 4 As shown, the auxiliary power supply 14 of this embodiment is also connected to the AC power through the rectifier circuit 12 and the switch switching circuit 11. When the output power of the auxiliary power supply 14 is less than or equal to the power threshold, the AC power charges the auxiliary power supply 14 through the switch switching circuit 11 and the rectifier circuit 12.

[0064] In summary, when the output power of the auxiliary power supply 14 is less than or equal to the power threshold, the power supply circuit 10 of the present application controls the switch switching circuit 11 to be turned on through the driving circuit 13 to connect the mains, so that the mains charges the auxiliary power supply 14 through the switch switching circuit 11 and the rectifier circuit 12. Among them, the switch switching circuit 11 includes a relay 101, and the relay 101 adopts a two-state relay. The third end and the sixth end of the relay 101 are normally closed contacts of the relay 101. The third end and the sixth end of the relay 101 are connected to the mains as the first input end of the switch switching circuit 11. The relay 101 can be automatically reset by a control signal, so that the relay 101 is in the first state, which can avoid the auxiliary power supply 14 from being powered off and restarted, maintain the operation of the power supply system 40, maintain the reliable operation of the load 50, and avoid the load power supply interruption requiring manual restart. In addition, the number of times the auxiliary power supply 14 is powered off and restarted is reduced, which can reduce the damage of components in the circuit and increase the service life of the circuit.

[0065] The above-described implementations do not constitute a limitation on the protection scope of the technical solution. Any modifications, equivalent replacements and improvements made within the spirit and principles of the above-described implementations are included in the protection scope of the technical solution.

Claims

1. A power supply circuit, It is characterized in that Applied to a power supply system, the power supply system is used to supply power to a load, and the power supply circuit includes: A switch switching circuit, wherein a first input end of the switch switching circuit is connected to the mains; A rectifier circuit, wherein an input end of the rectifier circuit is connected to an output end of the switch circuit; A driving circuit connected to the control end of the switch switching circuit; An auxiliary power supply connected to the output end of the rectifier circuit; When the output power of the auxiliary power supply is less than or equal to the power threshold, the driving circuit is used to drive the first input end of the switch switching circuit to be connected with the output end of the switch switching circuit, and the AC power charges the auxiliary power supply through the rectifier circuit.

2. The power supply circuit according to claim 1, It is characterized in that When the output power of the auxiliary power supply is greater than the power threshold, the driving circuit is used to drive the first input end of the switch switching circuit and the output end of the switch switching circuit to disconnect.

3. The power supply circuit according to claim 2, It is characterized in that The switch switching circuit includes a relay and a coil, the first end and the eighth end of the relay are suspended, the second end and the seventh end of the relay serve as the output end of the switch switching circuit, the third end and the sixth end of the relay serve as the first input end of the switch switching circuit, the fourth end and the fifth end of the relay serve as the control end of the switch switching circuit, one end of the coil is connected to the fourth end of the relay, and the other end of the coil is connected to the fifth end of the relay.

4. The power supply circuit according to claim 3, It is characterized in that The driving circuit includes a first resistor and a switch, the first end of the switch is grounded, the second end of the switch is connected to the fifth end of the relay, one end of the first resistor is connected to the fourth end of the relay, the other end of the first resistor receives a reference voltage, and the control end of the switch receives a control signal.

5. The power supply circuit according to claim 4, It is characterized in that When the output power of the auxiliary power supply is less than or equal to the power threshold, the control signal controls the switch to be disconnected, the second end and the third end of the relay are connected, and the seventh end and the sixth end of the relay are connected; when the output power of the auxiliary power supply is greater than the power threshold, the control signal controls the switch to be turned on, the second end and the first end of the relay are connected, and the seventh end and the eighth end of the relay are connected.

6. The power supply circuit according to any one of claims 1 to 5, It is characterized in that The rectifier circuit includes a rectifier bridge, a second resistor, a third resistor, a first diode and a second diode. The first output end of the rectifier bridge is connected to the positive electrode of the first diode through the second resistor, and the second output end of the rectifier bridge is connected to the negative electrode of the second diode through the third resistor. The negative electrode of the first diode and the positive electrode of the second diode serve as the output end of the rectifier circuit.

7. The power supply circuit according to claim 6, It is characterized in that The rectifier circuit also includes a fourth resistor, a fifth resistor, a first capacitor and a second capacitor. The cathode of the first diode is connected to the anode of the second diode through the first capacitor and the second capacitor. The fourth resistor is connected in parallel with the first capacitor, and the fifth resistor is connected in parallel with the second capacitor.

8. The power supply circuit according to claim 7, It is characterized in that The power supply circuit also includes a third diode and a fourth diode, the first end of the load is connected to the positive end of the DC bus, the second end of the load is connected to the negative end of the DC bus, the positive end of the DC bus is connected to the positive electrode of the third diode, the negative electrode of the third diode is connected to the negative electrode of the first diode, the negative end of the DC bus is connected to the negative electrode of the fourth diode, and the positive electrode of the fourth diode is connected to the positive electrode of the second diode.

9. The power supply circuit according to claim 7, It is characterized in that The first end of the auxiliary power supply is connected to the cathode of the first diode, and the second end of the auxiliary power supply is connected to the anode of the second diode.

10. A power supply system, It is characterized in that Used to supply power to a load, the power supply system includes a photovoltaic energy storage unit and a power supply circuit as described in any one of claims 1 to 9, the photovoltaic energy storage unit is used to supply power to the load through a DC bus, and the power supply circuit is connected to the DC bus and is used to charge an auxiliary power supply of the power supply circuit through the DC bus.

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