Inverter circuit and power supply device

Abstract

The utility model relates to the technical field of power supplies, and discloses an inverter circuit and power supply equipment, the inverter circuit comprises an adjusting module, the input end of the adjusting module is connected with a plurality of direct current output ends, and the adjusting module is used for combining the direct current voltage of the direct current output ends into one path for output; the input end of the conversion module is connected with the output end of the adjusting module, the output end of the conversion module is connected with a load, and the conversion module is used for receiving the combined direct-current voltage, converting the direct-current voltage into alternating-current voltage and outputting the alternating-current voltage to the load. The problem that multi-path input side energy of a miniature inverter is coupled together through a transformer in the prior art is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of power supplies, in particular to an inverter circuit and a power supply device. Background Art

[0002] Micro inverters are compact and widely used.

[0003] Current microinverters use a parallel connection approach for multiple inputs. However, this approach couples the input energy through the transformer, leading to the following issues in energy transfer from the input to the output: Due to reactive return and transformer energy coupling, the return current cannot fully flow through the output path, and soft switching cannot achieve the desired results. Furthermore, when performing reactive power regulation simultaneously on multiple inputs, the distribution of the return energy to multiple windings cannot be controlled, making reactive power precision regulation difficult. Utility Model Content

[0004] In view of this, the present invention provides an inverter circuit and a power supply device to solve the problem in the prior art that multiple input-side energies of a micro-inverter are coupled together through a transformer.

[0005] In a first aspect, the present invention provides an inverter circuit, the circuit comprising:

[0006] A regulating module, wherein the input end of the regulating module is connected to multiple DC output ends, and is used to combine the DC voltages of the multiple DC output ends into one output;

[0007] The conversion module has an input end connected to the output end of the regulation module, and an output end of the conversion module connected to the load, and is used to receive the combined DC voltage, convert the DC voltage into an AC voltage, and output the AC voltage to the load.

[0008] The regulation module combines the DC voltages of multiple DC output ends into one output to the conversion module. The conversion module converts the DC voltage of one channel into an AC voltage and outputs it to the load. Therefore, after the multiple input sides are converted into one input side, the conversion module only converts energy on one input side, thereby solving the problem of the energy of the multiple input sides of the micro inverter being coupled together through the transformer.

[0009] In an optional embodiment, the adjustment module includes:

[0010] Multiple voltage adjustment units, the input end of each voltage adjustment unit is connected to each DC output end respectively, and the output end of each voltage adjustment unit is connected to the input end of the conversion module, which is used to adjust the voltage of each DC output end to a preset voltage value respectively, and then merge them into one output to the conversion module.

[0011] In an optional embodiment, the DC output terminal includes: a positive electrode and a negative electrode, and the voltage adjustment unit includes:

[0012] a first inductor, wherein a first end of the first inductor is connected to the positive electrode of the DC output end;

[0013] a first diode, wherein a first end of the first diode is connected to the second end of the first inductor, and a second end of the first diode is connected to the conversion module;

[0014] A boost power switch tube, wherein the first end of the boost power switch tube is connected to the second end of the first inductor, and the second end of the boost power switch tube is respectively connected to the negative electrode of the DC output end and the conversion module.

[0015] In an optional embodiment, the conversion module includes:

[0016] a first conversion unit, wherein a first end of the first conversion unit is connected to the second end of the first diode, and a second end of the first conversion unit is connected to the negative electrode of the DC output terminal, and is used to convert the DC voltage into a high-frequency AC voltage for output;

[0017] A voltage transformation and isolation unit, wherein a first end of the voltage transformation and isolation unit is connected to a third end of the first conversion unit, and a second end of the voltage transformation and isolation unit is connected to a fourth end of the first conversion unit, and is used to regulate the high-frequency AC voltage and isolate the output;

[0018] a second conversion unit, wherein a first end of the second conversion unit is connected to a third end of the voltage transformation and isolation unit, and a second end of the second conversion unit is connected to a fourth end of the voltage transformation and isolation unit, and is configured to convert the regulated high-frequency AC voltage into an industrial frequency AC voltage for output;

[0019] A filter is provided, wherein a first end of the filter is connected to the third end of the second conversion unit, a second end of the filter is connected to the fourth end of the second conversion unit, and an output end of the filter is connected to the load.

[0020] In an optional embodiment, the conversion module further includes:

[0021] A DC support capacitor, wherein a first end of the DC support capacitor is connected to the second end of the first diode, and a second end of the DC support capacitor is connected to the negative electrode of the DC output end.

[0022] In an optional embodiment, the first conversion unit includes:

[0023] A full-bridge circuit is formed by a first power switch tube, a second power switch tube, a third power switch tube and a fourth power switch tube.

[0024] In an optional embodiment, the voltage transformation isolation unit includes:

[0025] a transformer, wherein a first input terminal of the transformer is connected to the third terminal of the first conversion unit, a second input terminal of the transformer is connected to the fourth terminal of the first conversion unit, a first output terminal of the transformer is connected to the first terminal of the second conversion unit, and a second output terminal of the transformer is connected to the second terminal of the second conversion unit;

[0026] a second inductor, wherein a first end of the second inductor is connected to the first input end of the transformer, and a second end of the second inductor is connected to the second input end of the transformer;

[0027] A third inductor, wherein a first end of the third inductor is connected to the first output end of the transformer, and a second end of the third inductor is connected to the first end of the second conversion unit.

[0028] In an optional embodiment, the voltage transformation isolation unit further includes: a resonant capacitor;

[0029] The resonant capacitor is connected between the second output terminal of the transformer and the second terminal of the second conversion unit; or,

[0030] The resonant capacitor is connected between the first output terminal of the transformer and the first terminal of the second conversion unit; or,

[0031] The resonant capacitor is connected between the third terminal of the first conversion unit and the first terminal of the second inductor; or,

[0032] The resonant capacitor is connected between the fourth terminal of the first conversion unit and the second terminal of the second inductor.

[0033] In an optional embodiment, the second conversion unit includes:

[0034] A half-bridge circuit consisting of a fifth power switch tube, a sixth power switch tube, a seventh power switch tube, an eighth power switch tube, a first capacitor and a second capacitor; or,

[0035] A full-bridge circuit is formed by a ninth power switch tube, a tenth power switch tube, an eleventh power switch tube, a twelfth power switch tube, a thirteenth power switch tube, a fourteenth power switch tube, a fifteenth power switch tube and a sixteenth power switch tube.

[0036] In a second aspect, the present invention provides a power supply device, which includes the above inverter circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0038] Figure 1 It is a traditional multi-input micro inverter;

[0039] Figure 2 It is another traditional multi-input micro inverter;

[0040] Figure 3 An inverter circuit structure diagram according to an embodiment of the present utility model;

[0041] Figure 4 A structural diagram of a regulating module in an inverter circuit according to an embodiment of the present utility model;

[0042] Figure 5 Another inverter circuit structure diagram according to an embodiment of the present utility model;

[0043] Figure 6 A structural diagram of a voltage conversion isolation unit in an inverter circuit according to an embodiment of the present utility model;

[0044] Figure 7 Another inverter circuit structure diagram according to an embodiment of the present invention. DETAILED DESCRIPTION

[0045] The following is a clear and complete description of the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0046] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating positions or relationships, are based on the positions or relationships shown in the accompanying drawings and are intended solely to facilitate the description of this utility model and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0047] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; they may refer to internal connections between two components; they may refer to wireless connections or wired connections. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0048] refer to Figure 1 and Figure 2 , the current micro inverter adopts parallel connection in the case of multiple inputs. Figure 1 The transformer includes multiple input sides and one output side. Figure 2 The system includes multiple transformers with one input and one output. However, this method couples the input energy through the transformer, resulting in the following problems in energy transfer from the input to the output. First, when only one of the multiple inputs is working, reactive power will flow back through the transformer and other windings, causing the voltage on the remaining unpowered inputs to rise. Second, due to the coupling of reactive power backflow and transformer energy, the return current cannot completely pass through the output power path, and soft switching cannot achieve the expected results. Third, when reactive power is regulated simultaneously on multiple inputs, the ratio of the return energy distributed to multiple windings cannot be controlled, making reactive power precision regulation difficult. Fourth, there is energy circulation between multiple inputs.

[0049] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0050] In this embodiment, an inverter circuit is provided. Figure 3 As shown, the circuit includes:

[0051] A regulating module 10, the input end of which is connected to a plurality of DC output terminals PV, and is used to combine the DC voltages of the multiple DC output terminals into one output;

[0052] Specifically, the multiple DC output terminals PV include PV1, PV2, ..., PVn. The voltages input to the multiple DC output terminals PV may be the same or different. The regulating module 10 combines the DC voltages input to the multiple DC output terminals PV into one channel for output. Optionally, the regulating module 10 may be a combining circuit.

[0053] The conversion module 20 has an input end connected to the output end of the regulation module 10 and an output end connected to the load, and is used to receive the combined DC voltage, convert the DC voltage into an AC voltage, and output the AC voltage to the load.

[0054] Specifically, the load can be a grid voltage terminal Grid, an electrical device, or a battery. The conversion module 20 converts the DC voltage of only one channel sent by the regulation module 10 into an AC voltage, and then outputs the AC voltage to the load. Optionally, the conversion module 20 can be a circuit that converts DC to AC. It should be noted that the conversion module 20 only includes one transformer, and the input side of the transformer is only connected to one input side. Since the transformer only needs to transmit the energy of one input side, it solves the problem of coupling the energy of multiple input sides of the micro inverter through the transformer. It is worth noting that the parts involving the method in this embodiment are all mature methods of the prior art.

[0055] In the inverter circuit provided in this embodiment, the regulation module 10 combines the DC voltages of multiple DC output terminals into one output, which is then output to the conversion module 20. The conversion module 20 converts the DC voltage of one channel into an AC voltage and then outputs it to the load. Thus, after the multiple input sides are converted into one input side, the conversion module only performs energy conversion on the one input side. Furthermore, since there is only one combined input side, the problem of the energy of the multiple input sides of the micro inverter being coupled together through the transformer is solved.

[0056] In some optional embodiments, such as Figure 4 As shown, the adjustment module 10 includes:

[0057] Multiple voltage regulating units 11, the input end of each voltage regulating unit is connected to each DC output end PV respectively, and the output end of each voltage regulating unit 11 is connected to the input end of the conversion module 20, which is used to regulate the voltage of each DC output end PV to a preset voltage value respectively, and then merge them into one output to the conversion module 20.

[0058] Specifically, when the input voltages of the multiple DC output terminals PV are different, each voltage regulating unit 11 is used to regulate each input voltage to a preset voltage value, so that the regulated voltage values ​​are all the same. If the different input voltages are directly combined together, it is equivalent to connecting different voltages in parallel, and the problem of different voltages in each circuit causing failure is solved. By using multiple voltage regulating units 11, the voltages of all DC output terminals PV are all regulated to the preset voltage value, which solves the problem of failure caused by different voltages in each circuit when different input voltages are combined together. Of course, the voltage regulating unit 11 can uniformly regulate the input voltages to a higher voltage value after all voltages are boosted, or uniformly regulate the input voltages to a lower voltage value after all voltages are bucked, or uniformly regulate the input voltages to an intermediate voltage value after all voltages are boosted or bucked. Optionally, the multiple voltage regulating units 11 can all be boost regulating units, or all be buck regulating units, or a combination of boost regulating units and buck regulating units.

[0059] In some optional embodiments, such as Figure 5 As shown, the DC output terminal PV includes a positive pole and a negative pole, and the voltage regulating unit 11 includes:

[0060] a first inductor L1, wherein a first end of the first inductor L1 is connected to the positive electrode of the DC output end;

[0061] A first diode D1, wherein a first end of the first diode D1 is connected to the second end of the first inductor L1, and a second end of the first diode D1 is connected to the conversion module 20;

[0062] The boost power switch tube Q1 has a first end connected to the second end of the first inductor L1 , and a second end connected to the negative electrode of the DC output end and the conversion module 20 .

[0063] Specifically, the voltage regulating unit 11 is a boost topology circuit composed of a first inductor L1, a first diode D1 and a boost power switch tube Q1. Of course, the voltage regulating unit 11 is not limited to the boost topology circuit composed of the first inductor L1, the first diode D1 and the boost power switch tube Q1, but can also be a boost circuit composed of other devices.

[0064] refer to Figure 5 , in this embodiment, Figure 5The regulating voltage unit 11 is entirely a boost topology, wherein the first inductor L1 includes L1-1, L1-2, ..., L1-n, the first diode D1 includes D1-1, D1-2, ..., D1-n, and the boost power switch tube Q1 includes Q1-1, Q1-2, ..., Q1-n, so that the voltage input by PV1 is adjusted to a preset voltage value through L1-1, D1-1, and Q1-1, and the voltage input by PV2 is adjusted to a preset voltage value through L1-2, D1-2, and Q1-2, and so on, and the voltages of all DC output terminals PV are uniformly adjusted to the preset voltage values ​​and then merged into one output to the conversion module 20.

[0065] The first diode D1 solves the problem of reactive backflow when only one of the multiple inputs is working, and the problem of energy circulation between multiple inputs causing the voltage of the remaining unpowered input sides to increase due to reactive backflow and the energy flowing through other windings of the transformer.

[0066] In some optional embodiments, such as Figure 5 As shown, the conversion module 20 includes:

[0067] A first conversion unit 21, wherein a first end of the first conversion unit 21 is connected to the second end of the first diode D1, and a second end of the first conversion unit 21 is connected to the negative electrode of the DC output terminal, and is configured to convert a DC voltage into a high-frequency AC voltage for output;

[0068] Specifically, the first conversion unit 21 is used for reactive power regulation. Since the first conversion unit 21 only performs reactive power regulation on one path, the accuracy of reactive power regulation is improved, and since the return current completely passes through the path for transmitting power, accurate soft switching control is achieved.

[0069] A voltage transformation and isolation unit 22, wherein a first end of the voltage transformation and isolation unit 22 is connected to a third end of the first conversion unit 21, and a second end of the voltage transformation and isolation unit 22 is connected to a fourth end of the first conversion unit 21, and is used to regulate the high-frequency AC voltage and isolate the output;

[0070] Specifically, the transformer isolation unit 22 is used to isolate the input side and the output side, and at the same time adjust the voltage of the input side and output it to the output side. Optionally, the transformer isolation unit 22 can boost the voltage of the input side and transmit it to the output side.

[0071] A second conversion unit 23, wherein a first end of the second conversion unit 23 is connected to a third end of the voltage transformation and isolation unit 22, and a second end of the second conversion unit 23 is connected to a fourth end of the voltage transformation and isolation unit 22, and is configured to convert the regulated high-frequency AC voltage into an industrial frequency AC voltage for output;

[0072] Specifically, the control device realizes reactive power regulation by controlling the second conversion unit 23 and the first conversion unit 21. Optionally, the second conversion unit 23 may be a full-bridge circuit or a half-bridge circuit.

[0073] The filter K1 has a first end connected to the third end of the second conversion unit 23 , a second end connected to the fourth end of the second conversion unit 23 , and an output end of the filter K1 connected to the load.

[0074] The filter K1 may specifically be an EMI suppression (Electromagnetic Interference, interference caused by electromagnetic fields) filter. Of course, it may also include any other filters to achieve filtering of other interference signals.

[0075] The DC voltage is converted into AC voltage by the first conversion unit 21, the voltage transformation and isolation unit 22, and the second conversion unit 23, and reactive power regulation is achieved at the same time. The configuration of the first conversion unit 21, the voltage transformation and isolation unit 22, and the second conversion unit 23 is conventional technology and will not be described in detail.

[0076] In some optional embodiments, such as Figure 5 As shown, the conversion module 20 further includes:

[0077] A DC support capacitor Cbus, wherein a first end of the DC support capacitor Cbus is connected to the second end of the first diode D1 , and a second end of the DC support capacitor Cbus is connected to the negative electrode of the DC output terminal.

[0078] Specifically, the DC support capacitor Cbus is provided at the input side of the conversion module 20 to provide voltage support and filter out harmonics.

[0079] In some optional embodiments, such as Figure 5 As shown, the first conversion unit 21 includes:

[0080] A full-bridge circuit is formed by a first power switch tube S1, a second power switch tube S2, a third power switch tube S3 and a fourth power switch tube S4.

[0081] Specifically, the first power switch tube S1, the second power switch tube S2, the third power switch tube S3 and the fourth power switch tube S4 are used to adjust the flow direction of the current on the input side of the transformer, thereby converting the DC voltage into the AC voltage. Optionally, the first conversion unit 21 can also be a conversion circuit of other forms.

[0082] In some optional embodiments, such as Figure 5 As shown, the transformer isolation unit 22 includes:

[0083] a transformer B1, wherein a first input terminal of the transformer B1 is connected to a third terminal of the first conversion unit 21, a second input terminal of the transformer B1 is connected to a fourth terminal of the first conversion unit 21, a first output terminal of the transformer B1 is connected to a first terminal of the second conversion unit 23, and a second output terminal of the transformer B1 is connected to a second terminal of the second conversion unit 23;

[0084] a second inductor L2, wherein a first end of the second inductor L2 is connected to the first input end of the transformer B1, and a second end of the second inductor L2 is connected to the second input end of the transformer B1;

[0085] The third inductor L3 has a first end connected to the first output end of the transformer B1 , and a second end connected to the first end of the second conversion unit 23 .

[0086] Specifically, the second inductor L2 is used for excitation and soft switching. Optionally, the second inductor L2 can be an excitation inductor provided within the transformer B1. The third inductor L3 serves as a freewheeling inductor for energy storage and transfer. Specifically, the third inductor L3 can be located on the path from point a to the second inductor L2 to point b, or on the path from point c to the third inductor L3 to point d. In other words, the third inductor L3 can be connected between the second output terminal of the transformer B1 and the second terminal of the second conversion unit 23, or between the third terminal of the first conversion unit 21 and the first terminal of the second inductor L2, or between the fourth terminal of the first conversion unit 21 and the second terminal of the second inductor L2. Optionally, the third inductor L3 can be a leakage inductor provided within the transformer B1.

[0087] In some optional embodiments, such as Figure 6 As shown, the voltage transformation isolation unit 22 further includes: a resonant capacitor Cr;

[0088] refer to Figure 6 (C) in the figure, the resonant capacitor Cr is connected between the second output terminal of the transformer B1 and the second terminal of the second conversion unit 23; or,

[0089] refer to Figure 6 In (A) and (B), the resonant capacitor Cr is connected between the first output terminal of the transformer B1 and the first terminal of the second conversion unit 23; or,

[0090] refer to Figure 6 In (D), the resonant capacitor Cr is connected between the third terminal of the first conversion unit 21 and the first terminal of the second inductor L2; or,

[0091] refer to Figure 6 In (E), the resonant capacitor Cr is connected between the fourth terminal of the first conversion unit 21 and the second terminal of the second inductor L2.

[0092] That is to say, the resonant capacitor Cr can be set on the path from point a to the second inductor L2 to point b, or on the path from point c to the third inductor L3 to point d, so as to achieve the purpose of a resonant inverter, and further, realize resonance to improve efficiency.

[0093] In some optional embodiments, such as Figure 5 and Figure 7 As shown, the second conversion unit 23 includes:

[0094] refer to Figure 5 The second conversion unit includes: a half-bridge circuit consisting of a fifth power switch tube S5, a sixth power switch tube S6, a seventh power switch tube S7, an eighth power switch tube S8, a first capacitor C1 and a second capacitor C2; or,

[0095] refer to Figure 7 The second conversion unit may include: a full-bridge circuit consisting of a ninth power switch tube S9, a tenth power switch tube S10, an eleventh power switch tube S11, a twelfth power switch tube S12, a thirteenth power switch tube S13, a fourteenth power switch tube S14, a fifteenth power switch tube S15 and a sixteenth power switch tube S16.

[0096] In addition, the second conversion unit can also be a circuit of any form, which is not limited here. Figure 7 For the full-bridge circuit shown in the figure, the resonant capacitor Cr can be set as follows: Figure 6 Any position in .

[0097] In this embodiment, the utility model provides a power supply device, which includes the above-mentioned inverter circuit and multiple DC output terminals PV and loads. The conversion module in the inverter circuit can be a DC to AC circuit in any form, and the regulation module can also be a boost topology circuit, a buck topology circuit, or a combination of a boost topology circuit and a buck topology circuit. The regulation module merges the DC voltages of multiple DC output terminals into one output to the conversion module, and the conversion module converts the DC voltage of one channel into an AC voltage and then outputs it to the load. Therefore, after the multiple input sides are converted into one input side, the conversion module only performs energy conversion on one input side, thereby solving the problem of the multiple input side energies of the micro inverter being coupled together through a transformer.

[0098] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations shall fall within the scope defined by the appended claims.

Claims

1. An inverter circuit, characterized in that: The circuit comprises: a regulating module, wherein an input end of the regulating module is connected to a plurality of DC output ends, and is used to combine the DC voltages of the plurality of DC output ends into one output; A conversion module, wherein the input end of the conversion module is connected to the output end of the regulation module, and the output end of the conversion module is connected to the load, is used to receive the combined DC voltage, convert the DC voltage into an AC voltage, and output the AC voltage to the load.

2. The circuit according to claim 1, wherein: The adjustment module includes: Multiple voltage adjustment units, the input end of each voltage adjustment unit is connected to each DC output end respectively, and the output end of each voltage adjustment unit is connected to the input end of the conversion module, for adjusting the voltage of each DC output end to a preset voltage value respectively, and then merging them into one output to the conversion module.

3. The circuit according to claim 2, characterized in that The DC output terminal includes: a positive electrode and a negative electrode, and the voltage adjustment unit includes: a first inductor, wherein a first end of the first inductor is connected to the positive electrode of the DC output end; a first diode, wherein a first end of the first diode is connected to the second end of the first inductor, and a second end of the first diode is connected to the conversion module; A boost power switch tube, wherein a first end of the boost power switch tube is connected to the second end of the first inductor, and a second end of the boost power switch tube is respectively connected to the negative electrode of the DC output end and the conversion module.

4. The circuit according to claim 3, characterized in that The conversion module includes: a first conversion unit, wherein a first end of the first conversion unit is connected to the second end of the first diode, and a second end of the first conversion unit is connected to the negative electrode of the DC output terminal, and is configured to convert a DC voltage into a high-frequency AC voltage for output; a voltage transformation and isolation unit, wherein a first end of the voltage transformation and isolation unit is connected to a third end of the first conversion unit, and a second end of the voltage transformation and isolation unit is connected to a fourth end of the first conversion unit, and is used to regulate the high-frequency AC voltage and output it in isolation; a second conversion unit, wherein a first end of the second conversion unit is connected to a third end of the voltage transformation and isolation unit, and a second end of the second conversion unit is connected to a fourth end of the voltage transformation and isolation unit, and is configured to convert the regulated high-frequency AC voltage into an industrial frequency AC voltage for output; A filter, wherein a first end of the filter is connected to the third end of the second conversion unit, a second end of the filter is connected to the fourth end of the second conversion unit, and an output end of the filter is connected to the load.

5. The circuit according to claim 4, characterized in that The conversion module further includes: A DC support capacitor, wherein a first end of the DC support capacitor is connected to the second end of the first diode, and a second end of the DC support capacitor is connected to the negative electrode of the DC output end.

6. The circuit according to claim 5, characterized in that The first conversion unit includes: A full-bridge circuit is formed by a first power switch tube, a second power switch tube, a third power switch tube and a fourth power switch tube.

7. The circuit according to claim 6, characterized in that The voltage transformation isolation unit includes: a transformer, wherein a first input terminal of the transformer is connected to the third terminal of the first conversion unit, a second input terminal of the transformer is connected to the fourth terminal of the first conversion unit, a first output terminal of the transformer is connected to the first terminal of the second conversion unit, and a second output terminal of the transformer is connected to the second terminal of the second conversion unit; a second inductor, wherein a first end of the second inductor is connected to the first input end of the transformer, and a second end of the second inductor is connected to the second input end of the transformer; a third inductor, wherein a first end of the third inductor is connected to the first output end of the transformer, and a second end of the third inductor is connected to the first end of the second conversion unit.

8. The circuit according to claim 7, characterized in that The voltage transformation isolation unit further includes: a resonant capacitor; The resonant capacitor is connected between the second output terminal of the transformer and the second terminal of the second conversion unit; or, The resonant capacitor is connected between the first output terminal of the transformer and the first terminal of the second conversion unit; or, The resonant capacitor is connected between the third terminal of the first conversion unit and the first terminal of the second inductor; or, The resonant capacitor is connected between the fourth terminal of the first conversion unit and the second terminal of the second inductor.

9. The circuit according to claim 8, characterized in that The second conversion unit includes: A half-bridge circuit consisting of a fifth power switch tube, a sixth power switch tube, a seventh power switch tube, an eighth power switch tube, a first capacitor and a second capacitor; or, A full-bridge circuit is formed by a ninth power switch tube, a tenth power switch tube, an eleventh power switch tube, a twelfth power switch tube, a thirteenth power switch tube, a fourteenth power switch tube, a fifteenth power switch tube and a sixteenth power switch tube.

10. A power supply device, characterized in that: The power supply device includes the inverter circuit according to any one of claims 1 to 9.

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