Power supply circuit of auxiliary power supply, auxiliary power supply and inverter

Abstract

The utility model relates to the technical field of power supply circuits, and discloses a power supply circuit of an auxiliary power supply, the auxiliary power supply and an inverter, comprising a voltage input circuit used for receiving a plurality of input voltages, performing selection processing on the plurality of input voltages, generating an input voltage signal, and performing voltage reduction processing on the input voltage signal, generating a voltage reference signal; and the voltage conversion circuit is connected with the voltage input circuit and is used for receiving the voltage reference signal and carrying out voltage reduction conversion processing on the voltage reference signal to generate at least one power supply voltage. According to the power supply circuit, multiple paths of input voltages can be received at the same time, the maximum voltage value in all the input voltages serves as input, then voltage reduction conversion is conducted through the subsequent voltage conversion circuit, and therefore it can be guaranteed that when one path of input voltage breaks down, the input voltage is not damaged. The auxiliary power supply can still convert other input voltages and output the voltages to the auxiliary power supply for power supply.

Description

TECHNICAL FIELD

[0001] The utility model relates to power supply circuit technical field, concretely relates to a kind of power supply circuit of auxiliary power supply, auxiliary power supply and inverter. BACKGROUND

[0002] The auxiliary power supply in the energy storage grid-connected inverter system is mainly used to power the control circuit and other low-voltage components inside the inverter, to provide stable power supply for the control unit, microprocessor and signal processing circuit of the inverter, to provide driving voltage for power switching devices such as IGBT or MOSFET, to support voltage and current monitoring circuits, to ensure safe operation of the equipment, and to provide overvoltage, undervoltage and short circuit protection functions. The auxiliary power supply in the energy storage grid-connected inverter system is usually designed as a high-efficiency switching power supply to reduce energy loss and improve the overall efficiency of the system. The requirements for the auxiliary power supply in the energy storage grid-connected inverter system are: stable output, providing continuous and stable power supply within a wide input voltage range; ensuring reliable operation of the system, providing electrical isolation between input and output to improve safety and reduce interference; adapting to different input voltage ranges to adapt to various grid environments and energy storage system configurations. In the energy storage grid-connected inverter system, the auxiliary power supply is one of the key components to ensure normal operation of the equipment, which provides necessary auxiliary power to support the control and monitoring functions of the inverter.

[0003] However, the existing auxiliary power supply in the energy storage grid-connected inverter system also has some disadvantages in design and application, such as the power supply source of the auxiliary power supply has only one way, which can cause the auxiliary power supply to fail to work normally if the power supply source fails, and the energy storage grid-connected inverter cannot operate normally. SUMMARY

[0004] The utility model provides a kind of power supply circuit of auxiliary power supply, auxiliary power supply and inverter to solve the above problems.

[0005] The utility model realizes by the following technical scheme:

[0006] A power supply circuit of auxiliary power supply, comprising:

[0007] A voltage input circuit is used to receive multiple input voltages, select and process the multiple input voltages, generate an input voltage signal, and reduce the voltage of the input voltage signal to generate a voltage reference signal;

[0008] A voltage conversion circuit is connected to the voltage input circuit, used to receive the voltage reference signal and reduce the voltage of the voltage reference signal to generate at least one power supply voltage.

[0009] As an optimization, the power supply circuit further comprises:

[0010] a feedback adjusting circuit, connected with the voltage input circuit, configured to receive the voltage reference signal and generate a feedback adjusting signal according to the voltage reference signal, and send the feedback adjusting signal to the voltage input circuit;

[0011] The voltage input circuit is further configured to adjust the voltage value of the voltage reference signal according to the feedback adjusting signal.

[0012] As an optimization, the voltage input circuit comprises:

[0013] a voltage selection unit, configured to receive a plurality of input voltages, perform maximum selection on the plurality of input voltages, and generate the input voltage signal;

[0014] a voltage reduction unit, connected with the voltage selection unit, configured to receive the input voltage signal and perform voltage reduction on the input voltage signal to generate the voltage reference signal.

[0015] As an optimization, the voltage conversion circuit comprises:

[0016] a first conversion unit, connected with the feedback adjusting circuit, configured to receive the feedback adjusting signal and generate a first supply voltage according to the feedback adjusting signal;

[0017] a second conversion unit, connected with the voltage input circuit, configured to receive the voltage reference signal and generate a second supply voltage according to the voltage reference signal

[0018] a third conversion unit, connected with the second voltage conversion circuit, configured to receive the second supply voltage and generate a third supply voltage according to the second supply voltage.

[0019] As an optimization, the feedback adjusting circuit comprises a capacitor C15, a capacitor C16 and a resistor R12, wherein the two ends of the capacitor C15, the capacitor C16 and the resistor R12 are connected in a head-to-tail manner, and the two ends of the capacitor C15 are connected with the voltage reduction unit respectively.

[0020] As an optimization, the first conversion unit comprises a resistor R16, a resistor R17, a resistor R19 and a capacitor C52; wherein the two ends of the resistor R16, the resistor R19 and the capacitor C52 are connected in a head-to-tail manner, the common connection end of the resistor R16 and the resistor R19 serves as an output end of the first conversion circuit, the common connection end of the resistor R16 and the capacitor C52 is grounded through the resistor R17 in series, and the common connection end of the resistor R16 and the capacitor C52 is further connected with the common connection end of the capacitor C15 and the capacitor C16.

[0021] As optimization, the second conversion unit comprises transformer L3, capacitor C48, voltage stabilizing diode D5, capacitor C43, resistor R1, resistor R25, resistor R32, resistor R33, resistor R35, capacitor C50, capacitor C36 and diode D7; wherein the first end of the primary coil of the transformer L3 is connected with the voltage reducing unit, the second end of the primary coil of the transformer L3 is connected with the ground in series with the capacitor C48, the first end of the secondary coil of the transformer L3 is connected with the negative electrode of the voltage stabilizing diode D5 in series with the capacitor C43 and the resistor R1 in turn, the negative electrode of the voltage stabilizing diode D5 is the output end of the second conversion unit, the second end of the secondary coil of the transformer L3 is connected with the positive electrode of the voltage stabilizing diode D5, the second end of the secondary coil of the transformer L3 is connected with the ground in series with the resistor R25 and the resistor R32 in turn, the common connection end of the resistor R25 and the resistor R32 is connected with the negative electrode of the diode D7, the positive electrode of the diode D7 is connected with the ground in series with the resistor R35 and the resistor R33 in turn, the positive electrode of the diode D7 is connected with the ground in series with the capacitor C36, and the negative electrode of the diode D7 is connected with the ground in series with the capacitor C50.

[0022] As optimization, the third conversion unit comprises chip U8, resistor R37, resistor R39, resistor R47, resistor R49 and capacitor C49; wherein the input pin of the chip U8 is connected with the common connection end of the resistor R1 and the capacitor C43, the ground pin and the enable pin of the chip U8 are grounded, the output pin of the chip U8 is the output end of the third conversion unit, the output pin of the chip U8 is connected with the first end of the resistor R37, the resistor R47 and the resistor R49 respectively, the second end of the resistor R37 is connected with the ground in series with the resistor R39, the second end of the resistor R47 is connected with the ground in series with the capacitor C49, the second end of the resistor R49 is grounded, and the second end of the resistor R37 is connected with the feedback pin of the chip U8.

[0023] The utility model discloses still disclose a kind of auxiliary power supply, and the auxiliary power supply includes the power supply circuit as described above, and the power supply circuit is used to power supply for the auxiliary power supply.

[0024] The utility model discloses still disclose a kind of inverter, and the inverter includes the auxiliary power supply as described above.

[0025] Compared with the prior art, the utility model has the following advantages and beneficial effects:

[0026] The power supply circuit of this invention can simultaneously receive multiple input voltages and take the maximum voltage value among all input voltages as the input. Then, the voltage is converted by the subsequent voltage conversion circuit. This ensures that when one input voltage fails, the auxiliary power supply can still convert the other input voltages and output them to power the auxiliary power supply. Attached Figure Description

[0027] The accompanying drawings, which are included to provide a further understanding of the embodiments of the present invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0028] Figure 1 A schematic diagram of the power supply circuit for an auxiliary power supply provided in this application. Figure 1 ;

[0029] Figure 2 A schematic diagram of the power supply circuit for an auxiliary power supply provided in this application. Figure 2 ;

[0030] Figure 3 A schematic diagram of the power supply circuit for an auxiliary power supply provided in this application. Figure 3 ;

[0031] Figure 4 A schematic diagram of a power supply circuit for an auxiliary power supply provided in this application.

[0032] The attached diagram shows the markings and corresponding component names:

[0033] 1-Voltage input circuit, 11-Voltage selection unit, 12-Step-down unit, 2-Voltage conversion circuit, 21-First conversion unit, 22-Second conversion unit, 23-Third conversion unit, 3-Feedback adjustment circuit, 4-Sampling circuit, 5-Main control circuit. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this utility model are only used to explain this utility model and are not intended to limit this utility model.

[0035] This embodiment 1 provides a power supply circuit for an auxiliary power supply, such as... Figure 1 As shown, it includes: voltage input circuit 1 and voltage conversion circuit 2.

[0036] Specifically, voltage input circuit 1 is used to receive multiple input voltages, select and process the multiple input voltages to generate an input voltage signal, and perform voltage reduction processing on the input voltage signal to generate a voltage reference signal.

[0037] The voltage reference signal here is Figure 4 the output voltage of the chip U7.

[0038] The voltage conversion circuit 2 is connected with the voltage input circuit 1, and the voltage conversion circuit 2 is used for receiving the voltage reference signal and performing step-down conversion processing on the voltage reference signal to generate at least one supply voltage.

[0039] As Figure 2 shown, the supply circuit of the auxiliary power supply further comprises a feedback adjustment circuit 3.

[0040] The feedback adjustment circuit 3 is connected with the voltage input circuit 1, and the feedback adjustment circuit 3 is used for receiving the voltage reference signal and generating a feedback adjustment signal according to the voltage reference signal and sending the feedback adjustment signal to the voltage input circuit 1.

[0041] The voltage input circuit 1 is further used for adjusting the voltage value of the voltage reference signal according to the feedback adjustment signal.

[0042] Next, the circuit of the utility model is introduced in detail.

[0043] As Figure 3 shown, in some embodiments, the voltage input circuit 1 comprises a voltage selection unit 11 and a step-down unit 12.

[0044] Specifically, the voltage selection unit 11 is used for receiving a plurality of input voltages, performing maximum selection processing on the plurality of input voltages to generate an input voltage signal; the voltage selection unit 11 is mainly composed of a diode group composed of a plurality of diodes, and each diode is connected with an input voltage respectively; the step-down unit 12 is connected with the voltage selection unit 11 and is used for receiving the input voltage signal and performing step-down processing on the input voltage signal to generate the voltage reference signal. The step-down unit 12 comprises a chip U7 and a peripheral circuit thereof.

[0045] More specifically, referring to Figure 4 shown, in the voltage input circuit 1, a plurality of input voltages are connected with the voltage input pin Vin of the chip U7 through diodes in the series diode group respectively, wherein the anode of the diode in the diode group is connected with the input voltage, the cathode of the diode is connected with the voltage input pin Vin of the chip U7, the PH pin and the boot pin of the chip U7 are connected through a series capacitor C41, the ground pin VDD of the chip U7 is connected with the control end of the main control circuit 5 through a series resistor R20, the ground pin VDD of the chip U7 is grounded through a series capacitor C20, and the end of the resistor R20 away from the capacitor C20 is grounded through a series capacitor C23.

[0046] As Figure 4As shown, the ON / OFF port is the control output terminal of the main control circuit 5. The main control circuit 5 is the main control circuit 5 in the auxiliary power supply and also one of the receiving terminals of the power supply circuit. That is, one of the output voltages of the power supply circuit supplies power to the main control circuit 5. In this embodiment, the voltage output by the third conversion unit 23 supplies power to the main control circuit 5. The main control circuit 5 inputs the output switch control signal from the ON / OFF port to the chip U7, thereby controlling the working state of the chip U7.

[0047] It should be noted that the main control circuit 5 of the auxiliary switch is an existing circuit, which can use existing control chips to achieve specific functions. At the same time, the output of the switch control signal by the main control circuit 5 to control the opening or closing of the chip U7 is also existing technology, which will not be elaborated here.

[0048] In some embodiments, the multiple input voltages include any two or three of the following: photovoltaic voltage PV, battery voltage BAT, and grid voltage VIN+ after rectification.

[0049] like Figure 4 As shown, each input voltage is connected to the voltage input pin Vin of chip U7 through a diode. The voltage VIN+ after rectification of the grid voltage is connected to the voltage input pin Vin of chip U7 through diode D1. The photovoltaic voltage PV is connected to the voltage input pin Vin of chip U7 through diode D2. The voltage VIN+ after rectification of the grid voltage is connected to the voltage input pin Vin of chip U7 through diode D3.

[0050] In this embodiment, the multiple power supply sources include three, that is, the power supply circuit of the main control circuit 5 has three inputs: BAT, PV and VIN+. It can be understood that the voltage input circuit 1 uses the voltage of the source with the larger voltage as the input voltage.

[0051] This is because the negative terminals of the three diodes D1, D2, and D3 are all connected to one pin. The voltage of the highest voltage received by the three diodes will flow back to the other two diodes, preventing the other two diodes from receiving voltage input.

[0052] In some embodiments, the feedback adjustment circuit 3 includes capacitor C15, capacitor C16 and resistor R12, wherein the two ends of capacitor C15, capacitor C16 and resistor R12 are connected end to end, and the two ends of capacitor C15 are respectively connected to the step-down unit 12.

[0053] In some embodiments, the voltage conversion circuit 2 includes a first conversion unit 21, a second conversion unit 22, and a third conversion unit 23.

[0054] The first conversion unit 21 is connected to the feedback adjustment circuit 3 and is used to receive the feedback adjustment signal and generate the first supply voltage according to the feedback adjustment signal.

[0055] More specifically, the first conversion unit 21 includes resistors R16, R17, and R19, and capacitor C52; wherein the two ends of resistors R16, R19, and capacitor C52 are connected end-to-end, and the common connection terminal of resistors R16 and R19 serves as the output terminal of the first conversion circuit, i.e. Figure 4 In the 12VP, the common connection terminal of resistor R16 and capacitor C52 is grounded through series resistor R17, and the common connection terminal of resistor R16 and capacitor C52 is also connected to the common connection terminal of capacitor C15 and capacitor C16.

[0056] In this embodiment, the first ends of resistor R12 and capacitor C15 are both connected to the compensation pin Comp of chip U7. The second end of resistor R12 is connected to the second end of capacitor C15 through series capacitor C16. The common connection end of capacitor C15 and capacitor C16 is connected to the feedback pin FB of chip U7.

[0057] The second conversion unit 22 is connected to the voltage input circuit 1 and is used to receive the voltage reference signal and generate a second supply voltage based on the voltage reference signal.

[0058] The second conversion unit 22 includes a transformer L3, a capacitor C48, a Zener diode D5, a capacitor C43, resistors R1, R25, R32, R33, and R35, a capacitor C50, a capacitor C36, and a diode D7. The first terminal of the primary coil of transformer L3 is connected to the step-down unit 12. The second terminal of the primary coil of transformer L3 is grounded through a series capacitor C48. The first terminal of the secondary coil of transformer L3 is connected to the negative terminal of the Zener diode D5 through a series capacitor C43 and a resistor R1. Connect the negative terminal of the Zener diode D5 to the output terminal of the second conversion unit 22. Connect the second terminal of the secondary coil of transformer L3 to the positive terminal of Zener diode D5. Connect the second terminal of the secondary coil of transformer L3 to ground through resistors R25 and R32 in series. Connect the common terminal of resistors R25 and R32 to the negative terminal of diode D7. Connect the positive terminal of diode D7 to ground through resistors R35 and R33 in series. Connect the positive and negative terminals of diode D7 to ground through capacitors C36 and C50 in series, respectively.

[0059] Here, the common connection terminal of the primary coil of transformer L3 and capacitor C48 is connected to the common connection terminal of resistor R19 and resistor R16.

[0060] The third conversion unit 23 is connected to the second voltage conversion circuit 2 and is used to receive the second power supply voltage and generate the third power supply voltage according to the second power supply voltage.

[0061] It should be noted that the third power supply voltage is lower than the second power supply voltage, while the first and second power supply voltages can be the same.

[0062] The third conversion unit 23 includes chip U8, resistors R37, R39, R47, R49, and capacitor C49. The input pin IN of chip U8 is connected to the common connection point of resistor R1 and capacitor C43. The ground pin GND and enable pin EN of chip U8 are grounded. The output pin OUT of chip U8 serves as the output terminal of the third conversion unit 23. The output pin OUT of chip U8 is connected to the first terminals of resistors R37, R47, and R49 respectively. The second terminal of resistor R37 is grounded through series resistor R39, the second terminal of resistor R47 is grounded through series capacitor C49, and the second terminal of resistor R49 is grounded. The common connection point of resistors R37 and R39 is connected to the FB pin of chip U8.

[0063] The resistors R37 and R39 can be used to divide the third supply voltage, and the feedback of the third supply voltage can be achieved through the feedback pin FB of chip U8.

[0064] Here, a sampling circuit 4 can also be set. The sampling circuit 4 includes resistors R34 and R36 and capacitor C42. Resistor R34 is grounded through resistor R36 and capacitor C42 connected in series. The common connection terminal of resistors R34 and R36 is connected to the common connection terminal of resistors R35 and R33. The end of resistor R34 away from resistor R36 is connected to the output terminal of the third conversion unit 23 (i.e., the output pin OUT of chip U8) for sampling the output voltage of the third conversion unit 23, that is, sampling the voltage that supplies power to the main control circuit 5. The common connection terminal of resistor R36 and capacitor C42 is connected to the sampling pin AD01 of the main control circuit 5. When the main control circuit 5 samples that the output voltage of chip U8 is lower than the set value, the main control circuit 5 can send a switch control signal to control chip U7 to turn off through the aforementioned NO / OFF port.

[0065] like Figure 4 As shown, this embodiment outputs three voltages, such as grid voltage VIN+, battery voltage BAT, and photovoltaic voltage PV_dc. The voltage with the highest voltage among these three will be selected as the input voltage signal. The voltage input circuit performs a step-down process on the input voltage signal to generate a voltage reference signal. The voltage reference signal is then converted by the first conversion circuit to obtain 12VP. 12VP represents the 12V supply voltage on the primary side, which is used to power the primary-side driver chip of the auxiliary power supply. A voltage divider resistor is also set. By controlling the resistance values ​​of resistors R16 and R17, the voltage of 12VP can be controlled to be maintained at 12V, thus stabilizing the voltage.

[0066] The voltage reference signal is converted into 12VS by the second conversion circuit and used to power the secondary driver chip of the auxiliary power supply.

[0067] The voltage reference signal is converted into V33D by the third conversion circuit. V33D represents a 3.3V voltage and is used to power the main control circuit 5 of the auxiliary power supply.

[0068] It should be noted that the primary-side driver chip, secondary-side driver chip, and main control circuit 5 of the auxiliary power supply are not protected by this utility model. It is only necessary to understand that the power supply circuit of this utility model can convert the maximum voltage among multiple power sources.

[0069] It should also be noted that chips U7 and U8 are existing chips, so they will not be discussed further here.

[0070] Example 2 also discloses an auxiliary power supply, which includes a power supply circuit as in Example 1, and the power supply circuit is used to supply power to the auxiliary power supply.

[0071] By integrating the power supply circuit of this invention into the auxiliary power supply, the auxiliary power supply can be powered simultaneously by multiple input voltages, thus giving the auxiliary power supply better applicability and stability.

[0072] Furthermore, the integrated power supply circuitry enables auxiliary power supplies to achieve higher energy efficiency and flexibility, particularly in complex electrical systems requiring constantly changing voltage sources. By improving compatibility with multiple voltage inputs, this design also simplifies power management, reduces reliance on a single voltage source, and lowers the risk of system failure. Overall, this integrated design not only enhances the versatility of the power supply unit but also strengthens the overall safety and sustainability of the system, representing a positive exploration of future power equipment design directions.

[0073] Example 3 also discloses an inverter, the auxiliary power supply of which uses the auxiliary power supply as in Example 2.

[0074] This inverter uses the auxiliary power supply of this invention, which makes the inverter more widely applicable and the power supply process based on the auxiliary power supply is more stable.

[0075] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above description is only a specific embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A power supply circuit for an auxiliary power source, characterized in that, include: A voltage input circuit is used to receive multiple input voltages, select and process the multiple input voltages to generate an input voltage signal, and perform voltage reduction processing on the input voltage signal to generate a voltage reference signal; A voltage conversion circuit, connected to the voltage input circuit, is used to receive the voltage reference signal and perform a step-down conversion on the voltage reference signal to generate at least one supply voltage; A feedback adjustment circuit, connected to the voltage input circuit, is used to receive the voltage reference signal, generate a feedback adjustment signal based on the voltage reference signal, and send it to the voltage input circuit. The voltage input circuit is also used to adjust the voltage value of the voltage reference signal according to the feedback adjustment signal; The voltage input circuit includes: Voltage selection unit: used to receive multiple input voltages, perform a maximum selection process on the multiple input voltages, and generate the input voltage signal; Step-down unit: connected to the voltage selection unit, used to receive the input voltage signal, and perform step-down processing on the input voltage signal to generate the voltage reference signal.

2. The power supply circuit for an auxiliary power supply according to claim 1, characterized in that, The voltage conversion circuit includes: The first conversion unit is connected to the feedback adjustment circuit and is used to receive the feedback adjustment signal and generate a first supply voltage according to the feedback adjustment signal. The second conversion unit is connected to the voltage input circuit and is used to receive the voltage reference signal and generate a second supply voltage according to the voltage reference signal. The third conversion unit, connected to the second conversion unit, is used to receive the second power supply voltage and generate a third power supply voltage based on the second power supply voltage.

3. The power supply circuit for an auxiliary power supply according to claim 1, characterized in that, The feedback adjustment circuit includes capacitor C15, capacitor C16 and resistor R12, wherein the two ends of capacitor C15, capacitor C16 and resistor R12 are connected end to end, and the two ends of capacitor C15 are respectively connected to the step-down unit.

4. The power supply circuit for an auxiliary power supply according to claim 2, characterized in that, The first conversion unit includes resistors R16, R17, and R19, and capacitor C52; wherein, The two ends of resistors R16 and R19 and capacitor C52 are connected end to end, and the common connection end of resistors R16 and R19 serves as the output end of the first conversion circuit. The common connection end of resistors R16 and C52 is grounded through resistor R17 in series, and the common connection end of resistors R16 and C52 is also connected to the common connection end of capacitors C15 and C16.

5. The power supply circuit for an auxiliary power supply according to claim 2, characterized in that, The second conversion unit includes a transformer L3, a capacitor C48, a Zener diode D5, a capacitor C43, resistors R1, R25, R32, R33, and R35, capacitors C50 and C36, and a diode D7; wherein, The first end of the primary coil of transformer L3 is connected to the step-down unit. The second end of the primary coil of transformer L3 is connected to ground via capacitor C48. The first end of the secondary coil of transformer L3 is connected to the negative terminal of Zener diode D5 via capacitor C43 and resistor R1 in series. The negative terminal of Zener diode D5 serves as the output terminal of the second conversion unit. The second end of the secondary coil of transformer L3 is connected to the positive terminal of Zener diode D5. The second end of the secondary coil of transformer L3 is connected to ground via resistor R25 and resistor R32 in series. The common connection terminal of resistors R25 and R32 is connected to the negative terminal of diode D7. The positive terminal of diode D7 is connected to ground via resistors R35 and R33 in series. The positive terminal of diode D7 is connected to ground via capacitor C3 in series. The negative terminal of diode D7 is connected to ground via capacitor C50 in series.

6. The power supply circuit for an auxiliary power supply according to claim 5, characterized in that, The third conversion unit includes chip U8, resistors R37, R39, R47, R49, and capacitor C49; wherein, The input pin of chip U8 is connected to the common connection terminal of resistor R1 and capacitor C43. The ground pin and enable pin of chip U8 are both grounded. The output pin of chip U8 serves as the output terminal of the third conversion unit. The output pin of chip U8 is connected to the first terminals of resistors R37, R47, and R49 respectively. The second terminal of resistor R37 is connected to ground after being connected in series with resistor R39. The second terminal of resistor R47 is connected to ground after being connected in series with capacitor C49. The second terminal of resistor R49 is grounded, and the second terminal of resistor R37 is connected to the feedback pin of chip U8.

7. An auxiliary power supply, characterized in that, The auxiliary power supply includes a power supply circuit as described in any one of claims 1-6, the power supply circuit being used to supply power to the auxiliary power supply.

8. An inverter, characterized in that, The inverter includes the auxiliary power supply as described in claim 7.

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