Alternating current and direct current auxiliary power supply circuit, energy distribution method of alternating current and direct current auxiliary power supply circuit and photovoltaic inverter

Abstract

The invention provides an AC / DC auxiliary power supply circuit and an energy distribution method thereof, and a photovoltaic inverter, and the energy distribution method comprises the steps: firstly obtaining the working parameters of a DC power conversion circuit, and determining the illumination intensity of a photovoltaic module and the power of a load; the direct-current power conversion circuit and the alternating-current power conversion circuit are correspondingly started based on the working parameters, the illumination intensity and the load power, and the output power of the two power conversion circuits is adaptively adjusted by matching the current illumination intensity with the current load intensity, so that the cooperative power supply of the two conversion circuits is realized, and the utilization rate of the alternating-current power conversion circuit is improved. The load requirements of the two power conversion circuits are reduced, the stability and reliability of the system are improved, and the power supply flexibility of the AC / DC auxiliary power supply circuit is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic inverters, and in particular relates to an AC / DC auxiliary power supply circuit and an energy distribution method thereof, and a photovoltaic inverter. Background Art

[0002] In the continuous iteration of photovoltaic inverter technology, auxiliary power plays a vital role. Auxiliary power is mainly used to provide stable power for control circuits, monitoring modules and other modules. At present, the DC auxiliary power supply and AC auxiliary power supply in most photovoltaic inverters operate independently of each other. Usually, during the day, the DC power generated by the photovoltaic panels is used to power the DC auxiliary power supply, while the AC auxiliary power supply is idle; at night or in weak light conditions, the system relies on the AC power supply.

[0003] This independent power supply solution has the following disadvantages:

[0004] First, in the existing design, the DC and AC auxiliary power supplies operate independently of each other, resulting in a waste of resources. The AC auxiliary power supply is idle during the day and is not effectively utilized, which increases the cost of the system.

[0005] Secondly, due to the independence of DC and AC auxiliary power supplies and the lack of a collaborative working mechanism, when the system load demand changes, the power supply mode is less flexible and cannot dynamically adjust the power distribution according to actual conditions.

[0006] In addition, the existing independent power supply solution also has limitations in temperature rise management. Since the DC and AC auxiliary power supplies operate independently, the transformer and power switch tube need to handle a larger power load, resulting in a higher temperature rise during operation, affecting the stability and reliability of the system. Excessive temperature rise not only shortens the service life of the device, but may also lead to additional heat dissipation requirements, further increasing the design complexity of the system. Summary of the invention

[0007] The purpose of the present invention is to provide an energy distribution method for an AC / DC auxiliary power supply circuit, aiming to solve the problems of low flexibility and reliability of traditional DC auxiliary power supply and AC auxiliary power supply working independently.

[0008] A first aspect of an embodiment of the present invention provides an energy distribution method for an AC / DC auxiliary power supply circuit, wherein the AC / DC auxiliary power supply circuit includes a DC power conversion circuit and an AC power conversion circuit, wherein the input end of the DC power conversion circuit is connected to a DC output bus terminal of a photovoltaic module, the input end of the AC power conversion circuit is connected to an AC power supply terminal, and the output end of the DC power conversion circuit and the output end of the AC power conversion circuit are connected together to form a power supply output end of the AC / DC auxiliary power supply circuit;

[0009] The energy distribution method comprises:

[0010] Obtaining the operating parameters of the DC power conversion circuit, and determining the light intensity of the photovoltaic module and the power of the load;

[0011] Based on the working parameters, the light intensity and the power of the load, the DC power conversion circuit and / or the AC power conversion circuit are controlled to be turned on and off accordingly, and the output power of the DC power conversion circuit and the output power of the AC power conversion circuit are adjusted.

[0012] Optionally, the operating parameters include input voltage, output power and temperature of the DC power conversion circuit;

[0013] The controlling of the DC power conversion circuit and / or the AC power conversion circuit on and off based on the working parameters, the light intensity and the power of the load, and adjusting the output power of the DC power conversion circuit and the output power of the AC power conversion circuit include:

[0014] When the light intensity of the photovoltaic module reaches a preset intensity, controlling the DC power conversion circuit to start and output the main power supply;

[0015] When the temperature of the DC power conversion circuit reaches a first temperature threshold and / or the power of the load reaches a first power threshold, controlling the AC power conversion circuit to start and output an auxiliary power supply;

[0016] The output power of the DC power conversion circuit and the output power of the AC power conversion circuit are adjusted based on the temperature of the DC power conversion circuit and / or the power size of the load.

[0017] Optionally, the controlling the on / off of the DC power conversion circuit and / or the AC power conversion circuit based on the operating parameter, the light intensity and the power of the load, and adjusting the output power of the DC power conversion circuit and the output power of the AC power conversion circuit, further includes:

[0018] When the illumination intensity of the photovoltaic module is less than a preset intensity, the DC power conversion circuit is controlled to be turned off and the AC power conversion circuit is controlled to output an auxiliary power supply.

[0019] Optionally, when the illumination intensity of the photovoltaic module is less than a preset intensity, the DC power conversion circuit is controlled to be turned off and the AC power conversion circuit is controlled to output an auxiliary power supply, further comprising:

[0020] The power size of the auxiliary power supply is adjusted based on the power size of the load.

[0021] Optionally, adjusting the output power of the DC power conversion circuit and the output power of the AC power conversion circuit based on the temperature of the power conversion circuit includes:

[0022] When the temperature reaches a second temperature threshold, the output power size and weight of the AC power conversion circuit are increased based on the power size of the load, and the output power size and weight of the DC power conversion circuit are reduced, and the second temperature threshold is greater than the first temperature threshold.

[0023] Optionally, adjusting the output power of the DC power conversion circuit and the AC power conversion circuit based on the power size of the load includes:

[0024] When the power of the load reaches a second power threshold, the output power size and weight of the AC power conversion circuit are increased based on the power size of the load, and the output power size and weight of the DC power conversion circuit are reduced, and the second power threshold is greater than the first power threshold.

[0025] Optionally, the adjusting the power output weight and size of the DC power conversion circuit and the AC power conversion circuit based on the power size of the load further includes:

[0026] Monitoring the direction of change of the load power;

[0027] When the power of the load decreases, reducing the output power size and weight of the AC power conversion circuit;

[0028] When the power of the load increases, the output power size and weight of the DC power conversion circuit are increased.

[0029] A second aspect of an embodiment of the present invention provides an AC / DC auxiliary power supply circuit, comprising a DC power conversion circuit, an AC power conversion circuit and an energy distribution control circuit, wherein the input end of the DC power conversion circuit is connected to the DC output bus terminal of the photovoltaic module, the input end of the AC power conversion circuit is connected to the AC power supply terminal, and the output end of the DC power conversion circuit and the output end of the AC power conversion circuit are connected together to form a power supply output end of the AC / DC auxiliary power supply circuit;

[0030] The energy distribution control circuit is connected to the DC power conversion circuit and the AC power conversion circuit respectively. The energy distribution control circuit includes a memory and a processing circuit, and a computer program stored in the memory and executable on the processing circuit. When the processing circuit executes the computer program, the steps of the energy distribution method described above are implemented.

[0031] Optionally, the DC power conversion circuit includes a first power switch circuit, a first transformer and a first rectifier filter circuit connected in sequence, and the first power switch circuit is also connected to the energy distribution control circuit;

[0032] The first power switch circuit is triggered to turn on by a first switch control signal output by the energy distribution control circuit, and converts an input first DC power supply into a first AC power supply through the first transformer, and is triggered to turn off by a first shutdown control signal output by the energy distribution control circuit;

[0033] The first rectifying and filtering circuit is used to perform rectification and filtering conversion on the first AC power supply and output a main power supply.

[0034] Optionally, the AC power conversion circuit includes a second rectifier and filter circuit, a second power switch circuit, a second transformer and a third rectifier and filter circuit connected in sequence, and the second power switch circuit is also connected to the energy distribution control circuit;

[0035] The second rectifying and filtering circuit is used to perform rectification and filtering conversion on the input second AC power supply and output a second DC power supply;

[0036] The second power switch circuit is triggered to turn on by the second switch control signal output by the energy distribution control circuit, and converts the second DC power supply into a third AC power supply through the second transformer, and is triggered to turn off by the second shutdown control signal output by the energy distribution control circuit;

[0037] The third rectifying and filtering circuit is used to perform rectification and filtering conversion on the third AC power supply and output an auxiliary power supply.

[0038] Optionally, the secondary windings of the first transformer and the second transformer are connected in a reused manner.

[0039] Optionally, the processing circuit includes:

[0040] A voltage sampling circuit is connected to the input end of the DC power conversion circuit, and is used to sample the voltage at the input end of the DC power conversion circuit and output a voltage sampling signal representing the light intensity;

[0041] A power detection circuit, connected to the output end of the DC power conversion circuit, for sampling the voltage and current of the output end of the DC power conversion circuit and outputting a power detection signal;

[0042] A temperature detection circuit is arranged relative to the DC power conversion circuit, and is used to detect the temperature of the DC power conversion circuit and output a temperature detection signal;

[0043] A controller is connected to the voltage sampling circuit, the power detection circuit, the temperature detection circuit, the DC power conversion circuit and the AC power conversion circuit respectively, and the controller is used to:

[0044] Determine the temperature, light intensity and load power of the DC power conversion circuit based on the voltage sampling signal, the power detection signal and the temperature sampling signal;

[0045] Based on the temperature of the DC power conversion circuit, the light intensity and the power of the load, the DC power conversion circuit and / or the AC power conversion circuit are controlled to be turned on and off accordingly, and the output power of the DC power conversion circuit and the output power of the AC power conversion circuit are adjusted.

[0046] A third aspect of the embodiments of the present invention provides a photovoltaic inverter, comprising the AC / DC auxiliary power supply circuit as described above.

[0047] Compared with the prior art, the embodiments of the present invention have the following beneficial effects: in the energy distribution method of the above-mentioned AC / DC auxiliary power supply circuit, the working parameters of the DC power conversion circuit are first obtained, and the light intensity of the photovoltaic module and the power size of the load are determined. Based on the working parameters, the light intensity and the power size of the load, the DC power conversion circuit and the AC power conversion circuit are started accordingly, and the output power of the two power conversion circuits is adaptively adjusted to match the current light intensity and load intensity, thereby realizing the coordinated power supply of the dual-path conversion circuits, improving the utilization rate of the AC power conversion circuit, reducing the load requirements of the two power conversion circuits, improving the system stability and reliability, and improving the power supply flexibility of the AC / DC auxiliary power supply circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0049] Figure 1 A schematic diagram of a first structure of an AC / DC auxiliary power supply circuit provided in an embodiment of the present invention;

[0050] Figure 2 A schematic diagram of a flow chart of an energy distribution method provided in an embodiment of the present invention;

[0051] Figure 3 for Figure 2 The schematic diagram of the process of step S200 in the energy distribution method shown;

[0052] Figure 4 A second structural schematic diagram of an AC / DC auxiliary power supply circuit provided in an embodiment of the present invention;

[0053] Figure 5 A third structural schematic diagram of an AC / DC auxiliary power supply circuit provided in an embodiment of the present invention;

[0054] Figure 6 A circuit diagram of an AC / DC auxiliary power supply circuit provided by an embodiment of the present invention;

[0055] Figure 7 A fourth structural schematic diagram of an AC / DC auxiliary power supply circuit provided in an embodiment of the present invention;

[0056] Figure 8 A fifth structural schematic diagram of the AC / DC auxiliary power supply circuit provided in an embodiment of the present invention.

[0057] Among them, the reference numerals in the figures are:

[0058] 10. DC power conversion circuit; 20. AC power conversion circuit; 30. Energy distribution control circuit; 11. First power switch circuit; 12. First rectifier filter circuit; 21. Second rectifier filter circuit; 22. Second power switch circuit; 23. Third rectifier filter circuit; 31. Memory; 32. Processing circuit; 321. Voltage sampling circuit; 322. Power detection circuit; 323. Temperature detection circuit; 324. Controller;

[0059] R1, first resistor; R2, second resistor; R3, third resistor; R4, fourth resistor; C1, first capacitor; C2, second capacitor; C3, third capacitor; C4, fourth capacitor; C5, fifth capacitor; C6, sixth capacitor; D1, first diode; D2, second diode; D3, third diode; D4, fourth diode; D5, fifth diode; D6, sixth diode; Q1, first switch tube; Q2, second switch tube; T1, first transformer; T2, second transformer; BR1, rectifier bridge;

[0060] DC, DC output bus terminal; AC, AC power terminal; Vout, power output terminal Vout of the AC / DC auxiliary power supply circuit. DETAILED DESCRIPTION

[0061] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0062] 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 one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0063] A first aspect of an embodiment of the present invention provides an energy distribution method for an AC / DC auxiliary power supply circuit, such as Figure 1 As shown, the AC / DC auxiliary power supply circuit includes a DC power conversion circuit 10 and an AC power conversion circuit 20. The input end of the DC power conversion circuit 10 is connected to the DC output bus terminal DC of the photovoltaic module, and the input end of the AC power conversion circuit 20 is connected to the AC power supply terminal AC. The output end of the DC power conversion circuit 10 and the output end of the AC power conversion circuit 20 are connected together to form a power output terminal Vout of the AC / DC auxiliary power supply circuit.

[0064] When the DC output bus terminal DC of the photovoltaic module has a DC power output and meets the working conditions, the DC power conversion circuit 10 can realize DC to DC conversion and output a DC power of corresponding size to the rear-end load, which can be a key module such as the control circuit and monitoring module in the photovoltaic inverter.

[0065] And when there is AC power input at the AC power supply end AC and the working conditions are met, the AC power conversion can convert the AC power at the AC power supply end AC into a DC power supply with the same voltage as the output end of the DC power conversion circuit 10, and the two power conversion circuits can realize current combined output to achieve coordinated power supply.

[0066] In order to realize the coordinated operation of the two power conversion circuits, reduce system cost and improve power supply flexibility and reliability, in an optional embodiment, as Figure 2 As shown, the energy allocation method includes:

[0067] S100 , obtaining the working parameters of the DC power conversion circuit 10 , and determining the light intensity of the photovoltaic module and the power of the load.

[0068] Among them, the input voltage, output voltage, input current, output current, output power, temperature and other working parameters of the DC power conversion circuit 10 can be obtained by setting a corresponding detection circuit or the original detection circuit of the photovoltaic inverter. Among them, the magnitude of the input voltage is related to the light intensity of the photovoltaic module. The stronger the light of the photovoltaic module, the higher the voltage of the DC output bus terminal DC of the photovoltaic module, and the higher the input voltage of the DC power conversion circuit 10. The weaker the light of the photovoltaic module, the lower the voltage of the DC output bus terminal DC of the photovoltaic module, and the smaller the input voltage of the DC power conversion circuit 10.

[0069] The output voltage and output current of the output end of the AC / DC auxiliary power supply circuit can determine the current, voltage and power of the load. Normally, the voltage of the load is constant, and the change of the output current corresponds to the change of the power.

[0070] S200, based on the working parameters, light intensity and load power, the DC power conversion circuit 10 and / or the AC power conversion circuit 20 are controlled to be turned on and off accordingly, and the output power of the DC power conversion circuit 10 and the output power of the AC power conversion circuit 20 are adjusted.

[0071] In this embodiment, after the working parameters, light intensity and load size are determined, the working parameters, light intensity and load power size are used as the working conditions of the DC power conversion circuit 10 and the working conditions of the AC power conversion circuit 20. When the working conditions change accordingly, the DC power conversion circuit 10 and / or the AC power conversion circuit 20 can be started or shut down accordingly to achieve coordinated power supply of the two power conversion circuits, and the output power of the two power conversion circuits can be adjusted accordingly to achieve that the output power of the two is equal to the load power and changes accordingly with the power size of the load.

[0072] Among them, in the initial stage of the AC / DC auxiliary power supply circuit, that is, when the system is started or idle, the DC power conversion circuit 10 and the AC power conversion circuit 20 are in a standby state, and the current system state is monitored by the corresponding sampling circuit. When the working conditions are met, the DC power conversion circuit 10 is started first as the main power supply circuit, and the AC power conversion circuit 20 is the auxiliary power supply circuit. When the current working environment of the DC power conversion circuit 10 does not meet the working conditions, such as the load is too large, the temperature is too high, etc., the AC power conversion circuit 20 is started, and the DC power conversion circuit 10 and the AC power conversion circuit 20 jointly supply power to the load. After starting the AC power conversion circuit 20, the working environment of the DC power conversion circuit 10 may change accordingly, such as the temperature is reduced, the output power is reduced, etc., so as to reduce the temperature of the DC power conversion circuit 10 or the load pressure of the switching device, ensure that the system temperature is controlled within a reasonable range, improve the circuit reliability, and realize the coordinated power supply of the DC power conversion circuit 10 and the AC power conversion circuit 20, reduce the independent working requirements of each power conversion circuit, and avoid excessive power load causing excessive temperature rise of the power device.

[0073] When the light intensity is too low and the input voltage of the DC power conversion circuit 10 does not meet the working conditions, the AC power conversion circuit 20 can be started accordingly, and the AC power conversion circuit 20 supplies power to the load to meet the different working environments of the AC / DC auxiliary power supply circuits.

[0074] In an optional embodiment, the operating parameters include the input voltage, output power and temperature of the DC power conversion circuit 10. By acquiring the input voltage of the DC power conversion circuit 10, the output voltage of the current photovoltaic module and the light intensity of the photovoltaic module can be determined.

[0075] Correspondingly, S200 includes:

[0076] S210 , when the light intensity of the photovoltaic module reaches a preset intensity, the DC power conversion circuit 10 is controlled to start and output the main power supply.

[0077] The AC / DC auxiliary power supply circuit monitors the light intensity of the photovoltaic module during the initialization stage. When the input voltage of the DC power conversion circuit 10 reaches the preset voltage, it indicates that the current light intensity of the photovoltaic module reaches the preset intensity. At this time, the working conditions of the DC power conversion circuit 10 are met, and the DC power conversion circuit 10 is started, and the main power supply of the corresponding size is output according to the power size of the load. At this time, the AC power conversion circuit 20 is in a standby state.

[0078] Correspondingly, when the light intensity of the photovoltaic module is low and cannot meet the working conditions of the DC power conversion circuit 10, it is necessary to start the AC power conversion circuit 20, that is, S200 also includes:

[0079] S240 , when the light intensity of the photovoltaic module is less than a preset intensity, the DC power conversion circuit 10 is controlled to be turned off and the AC power conversion circuit 20 is controlled to output an auxiliary power supply.

[0080] When the light intensity of the photovoltaic module is low, the voltage of the DC output bus terminal DC of the photovoltaic module is too low to meet the working voltage requirement of the DC power conversion circuit 10, and it enters the night mode and switches to start the AC power conversion circuit 20, and the AC power conversion circuit 20 works independently. At this time, the AC power conversion circuit 20 maintains the power supply demand of the load to ensure that the load can continue to operate.

[0081] Correspondingly, when the load changes at night, in order to meet the power demand of the load, in an optional embodiment, S240 further includes:

[0082] S250, adjusting the power size of the auxiliary power supply based on the power size of the load, that is, when the power of the load becomes larger, increasing the power size of the auxiliary power supply output by the AC power conversion circuit 20, and when the power of the load becomes smaller, reducing the power size of the auxiliary power supply output by the AC power conversion circuit 20, thereby reducing system power loss.

[0083] S220 , when the temperature of the DC power conversion circuit 10 reaches a first temperature threshold and / or the power of the load reaches a first power threshold, control the AC power conversion circuit 20 to start and output an auxiliary power supply.

[0084] When the DC power conversion circuit 10 is in normal working condition, the DC power conversion circuit 10 undertakes the main power supply task and realizes constant voltage and constant current output.

[0085] In order to avoid overload operation of a single power supply, a load judgment is performed by setting a corresponding first temperature threshold and a first load threshold. Among them, when the DC power conversion circuit 10 is powered alone and the temperature reaches the first temperature threshold, the first temperature threshold can be a set safety temperature threshold. At this time, there is an overtemperature risk when the DC power conversion circuit 10 continues to be powered alone. In order to prevent the temperature of the DC power conversion circuit 10 from further rising and to achieve the purpose of protecting the circuit and power devices, the AC power conversion circuit 20 is started accordingly, and the AC power conversion circuit 20 is controlled to provide part of the auxiliary power supply to share part of the load, thereby preventing the temperature of the DC power conversion circuit 10 from further rising and protecting the circuit and power devices.

[0086] And when the system load gradually increases, the output power of the DC power conversion circuit 10 reaches the maximum rated value. At this time, the corresponding monitoring circuit is used to determine whether the current output power of the DC power conversion circuit 10 reaches the first power threshold. When it is detected that the first power threshold is exceeded, the AC power conversion circuit 20 is started, and the AC power conversion circuit 20 is controlled to provide part of the auxiliary power supply to share part of the load. Under the first power threshold, the DC power conversion circuit 10 and the AC power conversion circuit 20 work together. The DC power conversion circuit 10 continues to provide the main part of the power as the main power supply circuit, and the AC power conversion circuit 20 provides the remaining power to supplement, ensuring that the output is stable and meets the power requirements of the load.

[0087] S230 , adjusting the output power of the DC power conversion circuit 10 and the output power of the AC power conversion circuit 20 based on the temperature of the DC power conversion circuit 10 and / or the power of the load.

[0088] After the synchronous control DC power conversion circuit 10 and the AC power conversion circuit 20 are started, the current DC power conversion circuit 10 and the load power may change with environmental changes or the progress of work. When the working environment changes, the output power size and weight of the DC power circuit can be adjusted accordingly according to the current temperature of the DC power conversion circuit 10, and the output power size and weight of the DC power conversion circuit 10 can be adjusted. For example, when the temperature rises further, the output power and weight of the AC power conversion circuit 20 can be increased, and the output power and weight of the DC power conversion circuit 10 can be reduced.

[0089] The step of adjusting the output power of the DC power conversion circuit 10 and the output power of the AC power conversion circuit 20 based on the temperature of the power conversion circuit includes:

[0090] S231. When the temperature reaches a second temperature threshold, the output power size and weight of the AC power conversion circuit 20 are increased based on the power size of the load, and the output power size and weight of the DC power conversion circuit 10 are reduced, and the second temperature threshold is greater than the first temperature threshold.

[0091] When the system continues to work and the temperature rise of the DC power conversion circuit 10 cannot be reduced to a safe range through the auxiliary power supply provided by the preliminary AC power conversion circuit 20, the system enters the control stage of the second temperature threshold. When it is detected that the temperature of the DC power conversion circuit 10 exceeds the second temperature threshold, the energy distribution method will not switch the main power supply mode at this time, but will choose to increase the output power size and weight of the AC power conversion circuit 20 to further share the power of the load and reduce the load and temperature rise of the DC power conversion circuit 10. At this time, the DC power conversion circuit 10 maintains a constant voltage output and reduces the output voltage. The AC power conversion circuit 20 provides more current to maintain the output stability of the total power tube.

[0092] Alternatively, the output power and weight of the DC power circuit and the output power and weight of the DC power conversion circuit 10 may be adjusted accordingly according to the power of the current load. For example, when the load power increases further, the output power and weight of the AC power conversion circuit 20 may be increased, and the AC power conversion circuit 20 bears more load power to ensure that the output of the DC power conversion circuit 10 remains within a safe range. Alternatively, when the load power decreases, the output power and weight of the AC power conversion circuit 20 may be reduced, and the DC power conversion circuit 10 may be gradually restored to be the main power supply circuit, thereby restoring the normal main-auxiliary source relationship.

[0093] Optionally, the step of adjusting the output power of the DC power conversion circuit 10 and the AC power conversion circuit 20 based on the power size of the load includes:

[0094] S232. When the power of the load reaches a second power threshold, the output power size and weight of the AC power conversion circuit 20 are increased based on the power size of the load, and the output power size and weight of the DC power conversion circuit 10 are reduced, and the second power threshold is greater than the first power threshold.

[0095] When the system continues to work and the load further increases, the system enters the control stage of the second power threshold. When it is detected that the power of the load exceeds the second power threshold, the energy distribution method will not switch the main power supply mode, but will choose to increase the output power and weight of the AC power conversion circuit 20. The AC power conversion circuit 20 intervenes in the power supply at a larger proportion to further share the power of the load and ensure that the output power of the DC power conversion circuit 10 remains within a safe range. At this time, the DC power conversion circuit 10 maintains a constant voltage output and reduces the output voltage. The AC power conversion circuit 20 provides more current to maintain the output stability of the total power tube to ensure constant voltage control, and the DC power conversion circuit 10 dominates the output voltage.

[0096] When the DC power conversion circuit 10 and the AC power conversion circuit 20 work together and supply power to the load, the power of the load may vary. In order to further optimize the efficiency of the system, in an optional embodiment, the power output weight and size of the DC power conversion circuit 10 and the AC power conversion circuit 20 are adjusted based on the power size of the load, and further includes:

[0097] S233, monitoring the change direction of load power;

[0098] S234, when the power of the load is reduced, reducing the output power and weight of the AC power conversion circuit 20;

[0099] S235. When the power of the load increases, the output power and weight of the DC power conversion circuit 10 are increased.

[0100] When the DC power conversion circuit 10 and the AC power conversion circuit 20 work together and supply power to the load, and the current load has not reached the second power threshold, the energy distribution method dynamically adjusts the power supply weights of the DC power conversion circuit 10 and the AC power conversion circuit 20 according to the load changes. When the load decreases, the energy distribution method first reduces the output power of the AC power conversion circuit 20, and gradually restores the DC power conversion circuit 10 to provide the main output power, restoring the normal main and auxiliary source relationship. When the load power drops to the first power threshold, the AC power conversion circuit 20 can enter the standby mode again. When the load is light, the DC power conversion circuit 10 operates at low power and maintains a constant voltage output to ensure that the system power consumption is minimized.

[0101] Similarly, when the load increases, the energy distribution method first increases the output power of the AC power conversion circuit 20 and increases the power supply weight of the AC power conversion circuit 20. When the second power threshold is not reached, the DC power conversion circuit 10 can provide the main power for the main power supply circuit. When the second power threshold is reached, the AC power conversion circuit 20 provides the main power, thereby achieving matching output of load power and coordinated work, and improving power supply flexibility and reliability.

[0102] Compared with the prior art, the embodiments of the present invention have the following beneficial effects: in the energy distribution method of the AC / DC auxiliary power supply circuit, the working parameters of the DC power conversion circuit 10 are first obtained, and the light intensity of the photovoltaic module and the power of the load are determined. Based on the working parameters, the light intensity and the power of the load, the DC power conversion circuit 10 and the AC power conversion circuit 20 are started accordingly, and the output powers of the two power conversion circuits are adaptively adjusted to match the current light intensity and load intensity, thereby realizing the coordinated power supply of the dual-path conversion circuits, improving the utilization rate of the AC power conversion circuit 20, reducing the load requirements of the two power conversion circuits, improving the system stability and reliability, and improving the power supply flexibility of the AC / DC auxiliary power supply circuit.

[0103] A second aspect of the embodiments of the present invention provides an AC / DC auxiliary power supply circuit, such as Figure 4 As shown, the AC / DC auxiliary power supply circuit includes a DC power conversion circuit 10, an AC power conversion circuit 20 and an energy distribution control circuit 30, the input end of the DC power conversion circuit 10 is connected to the DC output bus terminal DC of the photovoltaic module, the input end of the AC power conversion circuit 20 is connected to the AC power supply terminal AC, and the output end of the DC power conversion circuit 10 and the output end of the AC power conversion circuit 20 are connected together to form a power output terminal Vout of the AC / DC auxiliary power supply circuit;

[0104] The energy distribution control circuit 30 is connected to the DC power conversion circuit 10 and the AC power conversion circuit 20 respectively. The energy distribution control circuit 30 includes a memory 31 and a processing circuit 32, and a computer program stored in the memory 31 and executable on the processing circuit 32. When the processing circuit 32 executes the computer program, the steps of the above energy distribution method are implemented.

[0105] In this embodiment, when the DC output bus terminal DC of the photovoltaic module has a DC power output and the working conditions are met, the processing circuit 32 can control the DC power conversion circuit 10 to achieve DC to DC conversion based on the energy distribution method stored in the memory 31, and output a DC power supply of corresponding size to the rear-end load. The rear-end load can be a key module such as a control circuit and a monitoring module in the photovoltaic inverter.

[0106] And when there is AC power input at the AC power supply end AC, when the working conditions are met, the processing circuit 32 can control the AC power conversion based on the energy distribution method stored in the memory 31 to convert the AC power at the AC power supply end AC into a DC power supply with the same voltage as the output end of the DC power conversion circuit 10, and the two power conversion circuits can realize current combined output and realize collaborative power supply.

[0107] The processing circuit 32 obtains the working parameters, load, temperature, etc. of the DC power conversion circuit 10, and starts the DC power conversion circuit 10 and / or the AC power conversion circuit 20 accordingly, and allocates the output power and weight of the DC power conversion circuit 10 and the AC power conversion circuit 20 according to the load change, temperature change, and light change, thereby realizing the coordinated power supply of the dual-path conversion circuits, improving the utilization rate of the AC power conversion circuit 20, reducing the load requirements of the two power conversion circuits, improving the system stability and reliability, and improving the power supply flexibility of the AC / DC auxiliary power supply circuit.

[0108] The DC power conversion circuit 10 and the AC power conversion circuit 20 may include corresponding voltage conversion circuits, rectifier circuits, etc. In an optional embodiment, Figure 5 As shown, the DC power conversion circuit 10 includes a first power switch circuit 11, a first transformer T1 and a first rectifier filter circuit 12 connected in sequence, and the first power switch circuit 11 is also connected to the energy distribution control circuit 30;

[0109] The first power switch circuit 11 is triggered to turn on by the first switch control signal output by the energy distribution control circuit 30, and converts the input first DC power supply into the first AC power supply through the first transformer T1, and is triggered to turn off by the first shutdown control signal output by the energy distribution control circuit 30;

[0110] The first rectifying and filtering circuit 12 is used to perform rectification and filtering conversion on the first AC power supply and output the main power supply.

[0111] In this embodiment, the first power conversion circuit realizes DC to AC conversion. After the current working conditions of the DC power conversion circuit 10 are met, the processing circuit 32 in the energy distribution control circuit 30 outputs the corresponding first switch control signal and the first shutdown control signal based on the energy distribution method and the corresponding working parameters, temperature and load power. The first switch control signal can control the first power switch circuit 11 to turn on and control its output voltage and output current, thereby changing the output power of the DC power conversion circuit 10. The first shutdown control signal can control the first power switch circuit 11 to turn off, so as to cut off the output power to the first transformer T1 and the first rectifier filter circuit 12 at the rear end.

[0112] The first transformer T1 implements step-down conversion, and outputs the first AC power supply after stepping down the voltage to the first rectifier and filter circuit 12. The first rectifier and filter circuit 12 implements sorting conversion and outputs the main power supply.

[0113] The first power conversion circuit may adopt corresponding power tubes, capacitors, diodes and other structures, such as Figure 6As shown, in an optional embodiment, the first power switch circuit 11 includes a second capacitor C2, a first resistor R1, a first diode D1 and a first switch tube Q1, the first end of the second capacitor C2, the first end of the first resistor R1 and the first end of the primary winding of the first transformer T1 are connected to the positive electrode of the DC output bus terminal DC, the second end of the second capacitor C2, the second end of the first resistor R1 and the cathode of the first diode D1 are connected, the anode of the first diode D1, the second end of the primary winding of the first transformer T1 and the first end of the first switch tube Q1 are connected, the second end of the first switch tube Q1 is connected to the negative electrode of the DC output bus terminal DC, the second capacitor C2, the first diode D1, the primary winding of the first transformer T1 and the first switch tube Q1 constitute an AC to DC conversion module, and output AC power to the first rectifier and filter circuit 12 through the secondary winding of the first transformer T1.

[0114] Among them, a corresponding filtering circuit can also be set at the input end of the first power switch circuit 11. In an optional embodiment, the filtering circuit includes a first capacitor C1, and the first capacitor C1 is connected in parallel between the positive electrode of the DC output bus terminal DC and the negative electrode of the DC output bus terminal DC. The first capacitor C1 realizes filtering processing of the DC signal to reduce clutter interference.

[0115] The first rectifying and filtering circuit 12 can adopt a corresponding half-bridge rectifying circuit, a full-bridge rectifying circuit, etc. In an optional embodiment, as Figure 6 As shown, the first rectifying and filtering circuit 12 includes a second diode D2, a third capacitor C3 and a second resistor R2, the anode of the second diode D2 is connected to the first end of the secondary winding of the first transformer T1, the cathode of the second diode D2, the first end of the third capacitor C3 and the first end of the second resistor R2 are connected to form the positive electrode of the output end of the first rectifying and filtering circuit 12, the second end of the secondary winding of the first transformer T1, the second end of the third capacitor C3 and the second end of the second resistor R2 are connected to form the negative electrode of the output end of the first rectifying and filtering circuit 12, the second diode D2 realizes half-bridge rectification, and outputs the rectified main power supply to the rear-end load, wherein, in order to avoid the DC power output by the AC power conversion circuit 20 from being fed back to the first rectifying and filtering circuit 12, causing circuit damage, a first unidirectional conduction circuit is further arranged between the positive electrode of the output end of the AC / DC auxiliary power supply circuit and the positive electrode of the output end of the first rectifying and filtering circuit 12, the first unidirectional conduction circuit includes a third diode D3, the anode of the third diode D3 is connected to the positive electrode of the output end of the first rectifying and filtering circuit 12, and the cathode of the third diode D3 is connected to the positive electrode of the output end of the AC / DC auxiliary power supply circuit.

[0116] like Figure 5As shown, the AC power conversion circuit 20 includes a second rectifier and filter circuit 21, a second power switch circuit 22, a second transformer T2 and a third rectifier and filter circuit 23 which are connected in sequence, and the second power switch circuit 22 is also connected to the energy distribution control circuit 30;

[0117] The second rectifying and filtering circuit 21 is used to rectify and filter the input second AC power supply and output a second DC power supply;

[0118] The second power switch circuit 22 is triggered to turn on by the second switch control signal output by the energy distribution control circuit 30, and converts the second DC power supply into a third AC power supply through the second transformer T2, and is triggered to turn off by the second shutdown control signal output by the energy distribution control circuit 30;

[0119] The third rectifying and filtering circuit 23 is used to perform rectification and filtering conversion on the third AC power supply and output an auxiliary power supply.

[0120] In this embodiment, the second rectifier and filter circuit 21 rectifies the AC power input at the AC power supply end AC, and the second power conversion circuit realizes DC to AC conversion. After the current working conditions of the AC power conversion circuit 20 are met, the processing circuit 32 in the energy distribution control circuit 30 outputs the corresponding second switch control signal and second shutdown control signal based on the energy distribution method and the corresponding working parameters, temperature and load power. The second switch control signal can control the second power switch circuit 22 to turn on and control its output voltage and output current, thereby changing the output power of the AC power conversion circuit 20. The second shutdown control signal can control the second power switch circuit 22 to turn off, so as to cut off the output power to the second transformer T2 and the third rectifier and filter circuit 23 at the rear end.

[0121] The second transformer T2 implements step-down conversion, and outputs the second AC power supply after stepping down the voltage to the third rectifier and filter circuit 23. The third rectifier and filter circuit 23 implements sorting conversion and outputs the auxiliary power supply.

[0122] The second power conversion circuit may use corresponding power tubes, capacitors, diodes and other structures, such as Figure 6As shown, in an optional embodiment, the second power switch circuit 22 includes a fifth capacitor C5, a third resistor R3, a fourth diode D4 and a second switch tube Q2. The first end of the fifth capacitor C5, the first end of the third resistor R3 and the first end of the primary winding of the second transformer T2 are connected to the positive electrode of the output end of the second rectifier and filter circuit 21. The second end of the fifth capacitor C5, the second end of the third resistor R3 and the cathode of the fourth diode D4 are connected. The anode of the fourth diode D4, the second end of the primary winding of the second transformer T2 and the first end of the second switch tube Q2 are connected. The second end of the second switch tube Q2 is connected to the negative electrode of the output end of the second rectifier and filter circuit 21. The fifth capacitor C5, the fourth diode D4, the primary winding of the second transformer T2 and the second switch tube Q2 constitute an AC to DC conversion module, and output AC power to the third rectifier and filter circuit 23 through the secondary winding of the second transformer T2.

[0123] The second rectifying and filtering circuit 21 and the third rectifying and filtering circuit 23 can adopt corresponding half-bridge rectifying circuits, full-bridge rectifying circuits, etc. In an optional embodiment, as shown in FIG. Figure 6 As shown, the second rectifier and filter circuit 21 includes a rectifier bridge BR1 and a fourth capacitor C4. The first input terminal and the second input terminal of the rectifier bridge BR1 are respectively connected to the AC power supply terminal AC and correspond to the input AC power supply. The positive electrode of the output terminal of the rectifier bridge BR1 and the first end of the fourth capacitor C4 are connected to form the positive electrode of the output terminal of the second rectifier and filter circuit 21. The negative electrode of the output terminal of the rectifier bridge BR1 and the second end of the fourth capacitor C4 are connected to form the negative electrode of the output terminal of the second rectifier and filter circuit 21.

[0124] The third rectifying and filtering circuit 23 includes a fifth diode D5, a sixth capacitor C6 and a fourth resistor R4. The anode of the fifth diode D5 is connected to the first end of the secondary winding of the second transformer T2. The cathode of the fifth diode D5, the first end of the sixth capacitor C6 and the first end of the fourth resistor R4 are connected to form the positive electrode of the output end of the third rectifying and filtering circuit 23. The second end of the secondary winding of the second transformer T2, the second end of the sixth capacitor C6 and the second end of the fourth resistor R4 are connected to form the negative electrode of the output end of the third rectifying and filtering circuit 23. The fifth diode D5 realizes half-bridge rectification. The rectified main power supply is output to the rear-end load, wherein, in order to prevent the DC power output by the DC power conversion circuit 10 from being fed back to the third rectifier and filter circuit 23, causing circuit damage, a second unidirectional conduction circuit is further arranged between the positive pole of the output end of the DC power conversion circuit 20 and the positive pole of the output end of the third rectifier and filter circuit 23, and the second unidirectional conduction circuit includes a sixth diode D6, the anode of the sixth diode D6 is connected to the positive pole of the output end of the third rectifier and filter circuit 23, and the cathode of the sixth diode D6 is connected to the positive pole of the output end of the AC / DC auxiliary power supply circuit.

[0125] Furthermore, in order to simplify the coil and core structure of the transformer, as Figure 6 As shown, the secondary windings of the first transformer T1 and the second transformer T2 are connected and reused, that is, the second end of the secondary winding of the first transformer T1 is connected to the second end of the secondary winding of the second transformer T2 to form the same secondary winding. By reusing the secondary windings of the transformers, the volume of the magnetic core required for the transformers can be effectively reduced, thereby reducing the size of the first transformer T1 and the second transformer T2.

[0126] The processing circuit 32 may adopt corresponding detection circuits, processors, controllers, etc. In an optional embodiment, as Figure 7 As shown, the processing circuit 32 includes:

[0127] The voltage sampling circuit 321 is connected to the input end of the DC power conversion circuit 10, and is used to sample the voltage at the input end of the DC power conversion circuit 10, and output a voltage sampling signal representing the light intensity;

[0128] The power detection circuit 322 is connected to the output end of the DC power conversion circuit 10, and is used to sample the voltage and current of the output end of the DC power conversion circuit 10, and output a power detection signal;

[0129] The temperature detection circuit 323 is arranged relative to the DC power conversion circuit 10, and is used to detect the temperature of the DC power conversion circuit 10 and output a temperature detection signal;

[0130] The controller 324 is connected to the voltage sampling circuit 321, the power detection circuit 322, the temperature detection circuit 323, the DC power conversion circuit 10 and the AC power conversion circuit 20 respectively. The controller 324 is used to:

[0131] Determine the temperature, light intensity and load power of the DC power conversion circuit 10 based on the voltage sampling signal, the power detection signal and the temperature sampling signal;

[0132] Based on the temperature of the DC power conversion circuit 10, the light intensity and the power of the load, the DC power conversion circuit 10 and / or the AC power conversion circuit 20 are controlled to be turned on and off accordingly, and the output power of the DC power conversion circuit 10 and the output power of the AC power conversion circuit 20 are adjusted.

[0133] In this embodiment, the voltage sampling circuit 321 is connected to the DC output bus terminal DC and detects its voltage size, and outputs a voltage sampling signal of a corresponding proportion to the controller 324. The controller 324 can determine the current light intensity of the photovoltaic module based on the size of the voltage sampling signal, and then determine whether to start the AC power conversion circuit 20 or the DC power conversion circuit 10.

[0134] The voltage sampling circuit 321 may adopt corresponding structures such as a voltage transformer, a resistor voltage divider circuit, etc.

[0135] The power detection circuit 322 is used to detect the power size of the load. By detecting the output voltage and output current of the output end of the AC / DC auxiliary power supply circuit, the current, voltage and power size of the load can be determined. The power detection circuit 322 can use corresponding voltage transformers, current transformers, sampling resistors, resistor divider circuits, etc.

[0136] The controller 324 can determine the power size of the current load based on the power detection signal, and adjust the output power size and weight of the DC power conversion circuit 10 accordingly, as well as adjust the output power size and weight of the AC power conversion circuit 20 to match the load changes and ensure that the output of the DC power conversion circuit 10 remains within a safe range.

[0137] The temperature detection circuit 323 is arranged relative to the DC power conversion circuit 10 and obtains the temperature of the DC power conversion circuit 10. The controller 324 can determine whether to start the AC power conversion circuit 20 based on the temperature of the DC power conversion circuit 10, and whether to adjust the power output size and weight of the AC power conversion circuit 20 to further share the power of the load and reduce the load and temperature rise of the DC power conversion circuit 10.

[0138] The temperature detection circuit 323 may adopt corresponding temperature sensors, temperature-sensitive resistors and other structures.

[0139] Furthermore, when the AC power source is disconnected from the grid and the power is cut off, in order to avoid power interruption, in an optional embodiment, Figure 8 As shown, the voltage sampling circuit 321 is also connected to the input end of the AC power conversion circuit 20 and detects its voltage. When it is detected that its voltage is less than the preset voltage, the controller 324 can control the AC power conversion circuit 20 to shut down, and control the DC power conversion circuit 10 to supply power alone when the light is normal.

[0140] A third aspect of an embodiment of the present invention proposes a photovoltaic inverter, which includes an AC / DC auxiliary power supply circuit. The specific structure of the AC / DC auxiliary power supply circuit refers to the above embodiment. Since the photovoltaic inverter adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0141] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. An energy distribution method for an AC / DC auxiliary power supply circuit, characterized in that: The AC / DC auxiliary power supply circuit includes a DC power conversion circuit and an AC power conversion circuit, the input end of the DC power conversion circuit is connected to the DC output bus terminal of the photovoltaic module, the input end of the AC power conversion circuit is connected to the AC power supply terminal, and the output end of the DC power conversion circuit and the output end of the AC power conversion circuit are connected together to form the power output end of the AC / DC auxiliary power supply circuit; The energy distribution method comprises: Obtaining the operating parameters of the DC power conversion circuit, and determining the light intensity of the photovoltaic module and the power of the load; Based on the working parameters, the light intensity and the power of the load, the DC power conversion circuit and / or the AC power conversion circuit are controlled to be turned on and off accordingly, and the output power of the DC power conversion circuit and the output power of the AC power conversion circuit are adjusted.

2. The energy distribution method of the AC / DC auxiliary power supply circuit according to claim 1, characterized in that: The operating parameters include input voltage, output power and temperature of the DC power conversion circuit; The controlling the on and off of the DC power conversion circuit and / or the AC power conversion circuit based on the working parameters, the light intensity and the power of the load, and adjusting the output power of the DC power conversion circuit and the output power of the AC power conversion circuit include: When the light intensity of the photovoltaic module reaches a preset intensity, controlling the DC power conversion circuit to start and output the main power supply; When the temperature of the DC power conversion circuit reaches a first temperature threshold and / or the power of the load reaches a first power threshold, controlling the AC power conversion circuit to start and output an auxiliary power supply; The output power of the DC power conversion circuit and the output power of the AC power conversion circuit are adjusted based on the temperature of the DC power conversion circuit and / or the power size of the load.

3. The energy distribution method of the AC / DC auxiliary power supply circuit according to claim 2, characterized in that: The controlling of the DC power conversion circuit and / or the AC power conversion circuit on and off based on the working parameters, the light intensity and the power of the load, and adjusting the output power of the DC power conversion circuit and the output power of the AC power conversion circuit, further includes: When the illumination intensity of the photovoltaic module is less than a preset intensity, the DC power conversion circuit is controlled to be turned off and the AC power conversion circuit is controlled to output an auxiliary power supply.

4. The energy distribution method of the AC / DC auxiliary power supply circuit according to claim 3, characterized in that: When the light intensity of the photovoltaic module is less than a preset intensity, the DC power conversion circuit is controlled to be turned off and the AC power conversion circuit is controlled to output an auxiliary power supply, and further comprising: The power size of the auxiliary power supply is adjusted based on the power size of the load.

5. The energy distribution method of the AC / DC auxiliary power supply circuit according to claim 2, characterized in that: The adjusting the output power of the DC power conversion circuit and the output power of the AC power conversion circuit based on the temperature of the power conversion circuit includes: When the temperature reaches a second temperature threshold, the output power size and weight of the AC power conversion circuit are increased based on the power size of the load, and the output power size and weight of the DC power conversion circuit are reduced, and the second temperature threshold is greater than the first temperature threshold.

6. The energy distribution method of the AC / DC auxiliary power supply circuit according to claim 5, characterized in that: The adjusting the output power of the DC power conversion circuit and the AC power conversion circuit based on the power size of the load includes: When the power of the load reaches a second power threshold, the output power size and weight of the AC power conversion circuit are increased based on the power size of the load, and the output power size and weight of the DC power conversion circuit are reduced, and the second power threshold is greater than the first power threshold.

7. The energy distribution method of the AC / DC auxiliary power supply circuit according to claim 6, characterized in that: The step of adjusting the power output weight and size of the DC power conversion circuit and the AC power conversion circuit based on the power size of the load further includes: Monitoring the direction of change of the power of the load; When the power of the load decreases, reducing the output power size and weight of the AC power conversion circuit; When the power of the load increases, the output power size and weight of the DC power conversion circuit are increased.

8. An AC / DC auxiliary power supply circuit, characterized in that: It includes a DC power conversion circuit, an AC power conversion circuit and an energy distribution control circuit, wherein the input end of the DC power conversion circuit is connected to the DC output bus terminal of the photovoltaic module, the input end of the AC power conversion circuit is connected to the AC power supply terminal, and the output end of the DC power conversion circuit and the output end of the AC power conversion circuit are connected together to form the power supply output end of the AC / DC auxiliary power supply circuit; The energy distribution control circuit is connected to the DC power conversion circuit and the AC power conversion circuit respectively. The energy distribution control circuit includes a memory and a processing circuit, and a computer program stored in the memory and executable on the processing circuit. When the processing circuit executes the computer program, the steps of the energy distribution method as described in any one of claims 1 to 7 are implemented.

9. The AC / DC auxiliary power supply circuit according to claim 8, characterized in that: The DC power conversion circuit comprises a first power switch circuit, a first transformer and a first rectifier filter circuit connected in sequence, and the first power switch circuit is also connected to the energy distribution control circuit; The first power switch circuit is triggered to turn on by a first switch control signal output by the energy distribution control circuit, and converts an input first DC power supply into a first AC power supply through the first transformer, and is triggered to turn off by a first shutdown control signal output by the energy distribution control circuit; The first rectifying and filtering circuit is used to perform rectification and filtering conversion on the first AC power supply and output a main power supply.

10. The AC / DC auxiliary power supply circuit according to claim 9, characterized in that: The AC power conversion circuit comprises a second rectifier and filter circuit, a second power switch circuit, a second transformer and a third rectifier and filter circuit which are connected in sequence, and the second power switch circuit is also connected to the energy distribution control circuit; The second rectifying and filtering circuit is used to perform rectification and filtering conversion on the input second AC power supply and output a second DC power supply; The second power switch circuit is triggered to turn on by the second switch control signal output by the energy distribution control circuit, and converts the second DC power supply into a third AC power supply through the second transformer, and is triggered to turn off by the second shutdown control signal output by the energy distribution control circuit; The third rectifying and filtering circuit is used to perform rectification and filtering conversion on the third AC power supply and output an auxiliary power supply.

11. The AC / DC auxiliary power supply circuit according to claim 10, characterized in that: The secondary windings of the first transformer and the second transformer are connected in a reused manner.

12. The AC / DC auxiliary power supply circuit according to any one of claims 8 to 11, characterized in that: The processing circuit comprises: A voltage sampling circuit is connected to the input end of the DC power conversion circuit, and is used to sample the voltage at the input end of the DC power conversion circuit and output a voltage sampling signal representing the light intensity; A power detection circuit, connected to the output end of the DC power conversion circuit, for sampling the voltage and current of the output end of the DC power conversion circuit and outputting a power detection signal; A temperature detection circuit is arranged relative to the DC power conversion circuit, and is used to detect the temperature of the DC power conversion circuit and output a temperature detection signal; A controller is connected to the voltage sampling circuit, the power detection circuit, the temperature detection circuit, the DC power conversion circuit and the AC power conversion circuit respectively, and the controller is used to: Determine the temperature, light intensity and load power of the DC power conversion circuit based on the voltage sampling signal, the power detection signal and the temperature sampling signal; Based on the temperature of the DC power conversion circuit, the light intensity and the power of the load, the DC power conversion circuit and / or the AC power conversion circuit are controlled to be turned on and off accordingly, and the output power of the DC power conversion circuit and the output power of the AC power conversion circuit are adjusted.

13. A photovoltaic inverter, characterized in that: It comprises an AC / DC auxiliary power supply circuit as claimed in any one of claims 8 to 12.

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