Power conversion circuit and power supply system

Abstract

The invention discloses a power conversion circuit and a power supply system, the power conversion circuit comprises a plurality of boost circuits and a single-stage inverter, the plurality of boost circuits connected in parallel are connected with the single-stage inverter to realize an inversion topological structure, the inversion topological structure is simplified, the inversion conversion stage number is reduced, and the conversion efficiency is improved; and the output voltage after the plurality of boosted circuits are connected in parallel is lower than the output voltage after other circuits are connected in parallel, so that the safety and the reliability of the system are also improved.

Description

Technical Field

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

[0002] The inverter circuit with multiple inputs can simultaneously receive the DC voltage provided by multiple photovoltaic modules and invert it into corresponding AC power.

[0003] However, the above inverter circuit has a complex topological structure and requires multi-stage power conversion, which reduces the conversion efficiency. Summary of the invention

[0004] The present application provides a power conversion circuit and a power supply system to alleviate the technical problem of low conversion efficiency caused by complex inverter topology.

[0005] In a first aspect, the present application provides a power conversion circuit, which includes multiple boost circuits and a single-stage inverter, wherein the first port of each boost circuit is configured to transmit a corresponding first DC voltage, the second ports of the multiple boost circuits are connected in parallel and are configured to transmit a second DC voltage, and the first DC voltage is less than the second DC voltage; the first port of the single-stage inverter is connected to the second port of each boost circuit, and the second port of the single-stage inverter is configured to transmit AC power.

[0006] In a second aspect, the present application provides a power supply system, which includes the above-mentioned power conversion circuit and a plurality of photovoltaic components, each photovoltaic component is connected to a first port of a boost circuit.

[0007] The power conversion circuit and power supply system provided in the present application realize the inverter topology by connecting a single-stage inverter with multiple boost circuits connected in parallel, which simplifies the inverter topology, reduces the number of inverter conversion stages, and improves the conversion efficiency; and the output voltage of multiple boost circuits connected in parallel is lower than the output voltage of other circuits connected in parallel, which also improves the safety and reliability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The technical solution and other beneficial effects of the present application will be made apparent by describing in detail the specific implementation methods of the present application in conjunction with the accompanying drawings.

[0009] Figure 1 A first circuit schematic diagram of a power conversion circuit provided in an embodiment of the present application.

[0010] Figure 2 A second circuit schematic diagram of the power conversion circuit provided in an embodiment of the present application.

[0011] Figure 3This is a third circuit schematic diagram of the power conversion circuit provided in an embodiment of the present application.

[0012] Figure 4 A fourth circuit schematic diagram of the power conversion circuit provided in an embodiment of the present application.

[0013] Figure 5 A circuit schematic diagram of a power supply system provided in an embodiment of the present application.

[0014] Figure 6 for Figure 1 Schematic diagram of the working process of the power conversion circuit shown.

[0015] Figure 7 A control schematic diagram of a single-stage inverter provided in an embodiment of the present application. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0017] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or suggesting relative importance or implicitly indicating the number of technical features indicated. Therefore, the features specified as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0018] With the development of distributed photovoltaic power generation systems, micro inverters with single input in related technologies can only connect one photovoltaic module to generate electricity. This method has the problems of low system utilization and high cost.

[0019] In order to take into account the advantages of distributed power generation, improve the utilization rate of photovoltaic systems and reduce costs, multi-input micro inverters that can connect multiple photovoltaic modules have been widely used.

[0020] However, multi-input micro inverters are mostly low-efficiency two-stage topology solutions, which have problems such as low safety due to high bus voltage, and high size and price due to more semiconductor devices.

[0021] Among them, in the scenario where photovoltaics are applied to the balcony, the DC port of the micro-inverter needs to be connected to at least one of the battery and the photovoltaic module, and the micro-inverter also needs to realize the function of bidirectional power transmission.

[0022] The current multi-input micro inverter has multiple DC ports, which can be connected to photovoltaic modules or energy storage batteries. Each DC port is converted to DC high voltage through an LLC converter, and the output ports of each LLC converter are connected in parallel to form a high-voltage bus. The DC voltage in the high-voltage bus is converted to AC voltage through a full-bridge inverter for grid-connected operation. This solution requires 8 switching tubes and an isolation transformer for the LLC converter connected to each DC port, which is costly, large in size, and has low efficiency of the LLC converter. Moreover, the voltage on the high-voltage bus even reaches about 400V, which reduces the safety and reliability of the system.

[0023] In view of the shortcomings of the above-mentioned multi-input micro-inverter, such as low efficiency, high volume and high cost, the present application proposes a power conversion circuit, in which each DC port of the power conversion circuit is connected to a boost circuit, and the output ports of each boost circuit are connected in parallel to a single-stage inverter, so that a micro-inverter with a low-voltage bus can be formed based on a single-stage topology.

[0024] This embodiment provides a power conversion circuit. Figures 1 to 7 ,like Figures 1 to 5 As shown, the power conversion circuit includes multiple boost circuits 10 and a single-stage inverter 20, the first port of each boost circuit 10 is configured to transmit a corresponding first DC voltage, the second ports of the multiple boost circuits 10 are connected in parallel and configured to transmit a second DC voltage, and the first DC voltage is less than the second DC voltage; the first port of the single-stage inverter 20 is connected to the second port of each boost circuit 10, and the second port of the single-stage inverter 20 is configured to transmit AC power.

[0025] It can be understood that the power conversion circuit provided in this embodiment realizes the inverter topology by connecting multiple boost circuits 10 in parallel to a single-stage inverter 20, which simplifies the inverter topology, reduces the number of inverter conversion stages, and improves the conversion efficiency; and the output voltage after multiple boost circuits 10 are connected in parallel is lower than the output voltage after other circuits are connected in parallel, which also improves the safety and reliability of the system.

[0026] It should be noted that, compared with the high voltage bus reaching a high voltage of about 400V in the related art, the bus voltage formed by the second ports of multiple boost circuits 10 in parallel in this embodiment is about 50V, which also improves the safety and reliability of the system. The boost circuit 10 is used to convert the DC input voltage into a higher DC output voltage. The single-stage inverter 20 is used to convert the DC output voltage into AC power for grid-connected operation. In other embodiments, AC power can be used as an input voltage, and the first port of the boost circuit 10 is used to output a DC voltage to realize the bidirectional conversion of electric energy by the power conversion circuit. Vg represents grid-connected AC power.

[0027] In some embodiments, such as Figures 1 to 5 As shown, each boost circuit 10 includes a first inductor, a first switch tube and a second switch tube. The first end of the first inductor is configured as the positive electrode of the first port of the boost circuit 10; the first pole of the first switch tube is connected to the second end of the first inductor, and the second pole of the first switch tube is configured as the positive pole of the second port of the boost circuit 10; the first pole of the second switch tube is connected to the first pole of the first switch tube and the second end of the first inductor, and the second pole of the second switch tube is configured as the negative pole of the first port of the boost circuit 10 and the negative pole of the second port of the boost circuit 10.

[0028] It should be noted that the first inductor can be exemplarily L1...Ln, the first switch tube can be exemplarily Sa1...San, and the second switch tube can be exemplarily Sb1...Sbn, where n is an integer greater than or equal to 2. DC1...DCn represent the first ports of different boost circuits 10. In this embodiment, each boost circuit 10 is composed of only two switch tubes and one inductor, which reduces the volume and cost compared to the LLC converter in the related art that requires 8 switch tubes and one isolation transformer.

[0029] In some embodiments, the switching state of the first switch tube and the switching state of the second switch tube are used to control the boost circuit 10 to operate at a maximum power point.

[0030] It should be noted that the switching state of the first switch tube and the switching state of the second switch tube are controlled based on the maximum power point tracking (MPPT) technology, so as to control the boost circuit 10 to operate at the maximum power point, which can enable the boost circuit 10 to continuously output the maximum voltage and improve the conversion efficiency.

[0031] In some embodiments, such as Figures 1 to 5As shown, the single-stage inverter 20 includes a DC side bridge circuit 21, an AC transformer circuit 22 and an AC side bridge circuit 23, wherein the first port of the DC side bridge circuit 21 is connected to the second port of each boost circuit 10; the first port of the AC transformer circuit 22 is connected to the second port of the DC side bridge circuit 21; the first port of the AC side bridge circuit 23 is connected to the second port of the AC transformer circuit 22, and the second port of the AC side bridge circuit 23 is configured to transmit AC power.

[0032] It should be noted that the DC side bridge circuit 21 is used to convert the DC voltage into the AC voltage. The AC transformer circuit 22 is used to convert the amplitude of the AC voltage while realizing resonance processing to improve the conversion efficiency. The AC side bridge circuit 23 is used to convert the AC power output by the AC transformer circuit 22 into AC power for grid-connected operation.

[0033] In some embodiments, such as Figures 1 to 5 As shown, the DC side bridge circuit 21 includes a third switch tube M3, a fourth switch tube M4, a fifth switch tube M5 and a sixth switch tube M6. The first pole of the third switch tube M3 is configured as the positive pole of the first port of the DC side bridge circuit 21; the first pole of the fourth switch tube M4 is connected to the second pole of the third switch tube M3, and the second pole of the fourth switch tube M4 is configured as the negative pole of the first port of the DC side bridge circuit 21; the first pole of the fifth switch tube M5 is connected to the first pole of the third switch tube M3; the first pole of the sixth switch tube M6 is connected to the second pole of the fifth switch tube M5, and the second pole of the sixth switch tube M6 is connected to the second pole of the fourth switch tube M4; wherein the first pole of the fourth switch tube M4 and the first pole of the sixth switch tube M6 are respectively configured as the first pole and the second pole of the second port of the DC side bridge circuit 21.

[0034] It should be noted that the first electrode may be one of the source and the drain, and the second electrode may be the other of the source and the drain. For example, when the first electrode is the source, the second electrode is the drain; or, when the first electrode is the drain, the second electrode is the source. The third switch tube M3 and the fourth switch tube M4 are turned on in time-sharing mode, the fifth switch tube M5 and the sixth switch tube M6 are turned on in time-sharing mode, the third switch tube M3 and the sixth switch tube M6 are turned on synchronously at least part of the time, and the fourth switch tube M4 and the fifth switch tube M5 are turned on synchronously at least part of the time. The switch tube may be a MOS tube or a power tube.

[0035] Alternatively, if Figures 1 to 5 As shown, the DC side bridge circuit 21 further includes a first capacitor Cbus, a first end of the first capacitor Cbus is connected to a first electrode of the third switch tube M3, and a second end of the first capacitor Cbus is connected to a second electrode of the fourth switch tube M4.

[0036] It should be noted that the first capacitor Cbus, as a bus capacitor, can reduce voltage fluctuations and lower electromagnetic interference.

[0037] In some embodiments, such as Figure 1 , Figure 3 as well as Figure 5 As shown, the AC transformer circuit 22 includes a transformer, a second inductor Lm and a third inductor Lr, and the transformer includes a primary winding and a secondary winding; the first end of the second inductor Lm is connected to the second pole of the third switch tube M3 and the first end of the primary winding, and the second end of the second inductor Lm is connected to the second pole of the fifth switch tube M5 and the second end of the primary winding; the first end of the third inductor Lr is connected to the first end of the secondary winding, and the second end of the third inductor Lr is connected to the first pole of the first port of the AC side bridge circuit 23; wherein, the second end of the secondary winding is connected to the second pole of the first port of the AC side bridge circuit 23.

[0038] It should be noted that the ratio of the number of turns of the primary winding to that of the secondary winding is 1:K, where K is an integer greater than 1. The third inductor Lr may be a leakage inductor of a transformer or a discrete resonant inductor.

[0039] In some embodiments, such as Figure 2 , Figure 4 As shown, the AC transformer circuit 22 further includes a second capacitor Cr, a first end of the second capacitor Cr is connected to the second end of the secondary winding, and a second end of the second capacitor Cr is connected to the second pole of the first port of the AC side bridge circuit 23 .

[0040] It should be noted that the second inductor Lm, the third inductor Lr and the second capacitor Cr can form an LLC resonant circuit to further improve the conversion efficiency.

[0041] In some embodiments, the AC side bridge circuit 23 includes a first bridge arm and a second bridge arm connected in parallel, the midpoint of the first bridge arm serves as the first pole of the first port of the AC side bridge circuit 23, and the midpoint of the second bridge arm serves as the second pole of the first port of the AC side bridge circuit 23.

[0042] In some embodiments, such as Figures 1 to 5 As shown, the first bridge arm includes a seventh switch tube M7, an eighth switch tube M8, a ninth switch tube M9 and a tenth switch tube M10. The first electrode of the seventh switch tube M7 is connected to the first end of the second bridge arm; the first electrode of the eighth switch tube M8 is connected to the second electrode of the seventh switch tube M7, and the second electrode of the eighth switch tube M8 is connected to the second end of the third inductor Lr; the first electrode of the ninth switch tube M9 is connected to the second electrode of the eighth switch tube M8; the first electrode of the tenth switch tube M10 is connected to the second electrode of the ninth switch tube M9, and the second electrode of the tenth switch tube M10 is connected to the second end of the second bridge arm.

[0043] In some embodiments, such as Figure 1 , Figure 2 as well as Figure 5 As shown, the second bridge arm includes a third capacitor Cr1 and a fourth capacitor Cr2, the first end of the third capacitor Cr1 serves as the first end of the second bridge arm, and the second end of the third capacitor Cr1 is connected to the second end of the secondary winding or the second end of the second capacitor Cr; the first end of the fourth capacitor Cr2 is connected to the second end of the third capacitor Cr1 and serves as the midpoint of the second bridge arm, and the second end of the fourth capacitor Cr2 serves as the second end of the second bridge arm.

[0044] It should be noted that the third capacitor Cr1 and the fourth capacitor Cr2 are both microfarad-level capacitors, which serve as half-bridge support capacitors. In this case, the single-stage inverter 20 operates in a linear mode. Alternatively, the third capacitor Cr1 and the fourth capacitor Cr2 are both nanofarad-level capacitors, which can resonate with the third inductor Lr. In this case, the single-stage inverter 20 operates in a resonant mode.

[0045] In some embodiments, such as Figure 3 , Figure 4 As shown, the second bridge arm includes an eleventh switch tube M11, a twelfth switch tube M12, a thirteenth switch tube M13 and a fourteenth switch tube M14. The first pole of the eleventh switch tube M11 is connected to the first pole of the seventh switch tube M7, and is configured as the first pole of the second port of the AC side bridge circuit 23; the first pole of the twelfth switch tube M12 is connected to the second pole of the eleventh switch tube M11, and the second pole of the twelfth switch tube M12 is connected to the second end of the secondary winding or the second end of the second capacitor Cr; the first pole of the thirteenth switch tube M13 is connected to the second pole of the twelfth switch tube M12; the first pole of the fourteenth switch tube M14 is connected to the second pole of the thirteenth switch tube M13, and the second pole of the fourteenth switch tube M14 is connected to the second pole of the tenth switch tube M10 and is configured as the second pole of the second port of the AC side bridge circuit 23.

[0046] It should be noted that Figure 1 , Figure 3 as well as Figure 5 The single-stage inverter 20 in the embodiment works in linear mode. Figure 2 as well as Figure 4 The single-stage inverter 20 in FIG. 1 operates in a resonant mode.

[0047] In some embodiments, such as Figures 1 to 5 As shown, the power conversion circuit further includes a filter 30 connected between the AC side bridge circuit 23 and the power grid, and the filter 30 is used to suppress electromagnetic interference (EMI).

[0048] In some embodiments, such as Figure 5As shown, this embodiment provides a power supply system, which includes the above-mentioned power conversion circuit and a plurality of photovoltaic modules, each of which is connected to a first port of a boost circuit 10.

[0049] It can be understood that since the power supply system provided in this embodiment includes the above-mentioned power conversion circuit, it is also possible to realize the inverter topology by connecting a single-stage inverter 20 through multiple parallel-connected boost circuits 10, which simplifies the inverter topology, reduces the number of inverter conversion levels, and improves the conversion efficiency; and the output voltage after multiple boost circuits 10 are connected in parallel is lower than the output voltage after other circuits are connected in parallel, which also improves the safety and reliability of the system.

[0050] It should be noted that photovoltaic components can be exemplarily represented as PV1..PVn.

[0051] In some embodiments, such as Figure 5 As shown, the power supply system further includes one or more batteries, each of which is connected in parallel to the second port of the boost circuit 10 .

[0052] It should be noted that the battery can be exemplarily represented as Bat1 ... Batn. When the real-time voltage of the battery is higher than the open-circuit voltage of the photovoltaic module, the battery is connected in parallel to the second port of the boost circuit 10, which can save the circuit between the battery and the power conversion circuit, further reducing the volume and cost.

[0053] Figure 6 for Figure 1 The working process of the power conversion circuit is shown in the figure. Figures 1 to 5 , during the period from t0 to t5, the third drive signal S3 controlling the third switch tube M3 is at a high potential, and the third switch tube M3 is turned on; during the period from t6 to t11, the fourth drive signal S4 controlling the fourth switch tube M4 is at a high potential, and the fourth switch tube M4 is turned on; during the period from t12 to t14, the third drive signal S3 controlling the third switch tube M3 is at a high potential, and the third switch tube M3 is turned on. In the period Td1 between t11 and t12 and the period Td2 between t5 and t6, the third drive signal S3 and the fourth drive signal S4 are both at a low level to prevent the third switch tube M3 and the fourth switch tube M4 from being turned on synchronously. The third switch tube M3 and the fourth switch tube M4 are turned on alternately at the switching frequency.

[0054] After 2πD1 from time t0, time t2 is reached. During the period from t2 to t7, the sixth drive signal S6 controlling the sixth switch tube M6 is at a high potential, and the sixth switch tube M6 is turned on. During the period from t8 to t13, the fifth drive signal S5 controlling the fifth switch tube M5 is at a high potential, and the fifth switch tube M5 is turned on. In the period Td4 between t1 and t2 and the period Td3 between t7 and t8, the third drive signal S3 and the fourth drive signal S4 are both at a low level to prevent the third switch tube M3 from being turned on synchronously with the fourth switch tube M4. The fifth switch tube M5 and the sixth switch tube M6 are turned on alternately at the switching frequency.

[0055] After 2πD2 from time t0, time t4 is reached. During the period from t4 to t9, the seventh drive signal S7 for controlling the seventh switch tube M7 is at a high potential, and the seventh switch tube M7 is turned on. During the period from t10 to t14, the ninth drive signal S9 for controlling the ninth switch tube M9 is at a high potential, and the ninth switch tube M9 is turned on. In the period Td5 between t3 and t4 and the period Td7 between t9 and t10, the seventh drive signal S7 and the ninth drive signal S9 are both at a low level to prevent the seventh switch tube M7 from being turned on synchronously with the ninth switch tube M9. The seventh switch tube M7 and the ninth switch tube M9 are turned on alternately at the switching frequency.

[0056] Wherein, D1 is the inner phase shift angle between the switches in the DC side bridge circuit 21. D2 is the outer phase shift angle between the switches in the DC side bridge circuit 21 and the switches in the AC side bridge circuit 23. As the switches in the DC side bridge circuit 21 and the switches in the AC side bridge circuit 23 are turned on and off, the output voltage Vp of the DC side bridge circuit 21, the output voltage Vs of the AC side bridge circuit 23, and the current iL flowing through the third inductor Lr all change accordingly.

[0057] Figure 7 A control schematic diagram of a single-stage inverter 20 provided in an embodiment of the present application. The above-mentioned power conversion circuit or power supply system may also include a phase shift controller 40 and an adder, the adder is used to calculate the sum of the reference external phase shift angle D2` and the external phase shift angle offset △D2, and obtain D2, which can improve the accuracy of D2. The phase shift controller 40 is used to obtain the third drive signal S3 to the sixth drive signal S6, that is, S3~S6 and the seventh drive signal S7 to the tenth drive signal S10, that is, S7~S10, according to D1, D2 and the switching frequency, that is, Fs. The eleventh drive signal S11 to the fourteenth drive signal S14, that is, S11~S14, can also be selectively obtained.

[0058] Wherein, D1 can be obtained according to the voltage matching constraint condition. The reference external phase shift angle D2' can be obtained according to the power transmission constraint condition. Fs can be obtained based on D1 and the reference external phase shift angle D2' according to the switching frequency constraint condition. io represents the grid-connected current output by the single-stage inverter 20.

[0059] The third drive signal S3 to the sixth drive signal S6, i.e., S3~S6, are used to sequentially drive the third switch tube M3 to the sixth switch tube M6 in the DC side bridge circuit 21. The seventh drive signal S7 to the tenth drive signal S10, i.e., S7~S10, are used to sequentially drive the seventh switch tube M7 to the tenth switch tube M10 in the first bridge arm. The eleventh drive signal S11 to the fourteenth drive signal S14, i.e., S11~S14, are used to sequentially drive the eleventh switch tube M11 to the fourteenth switch tube M14 in the second bridge arm.

[0060] It should be noted that in this way, the efficiency of the single-stage inverter 20 can be optimized, thereby further improving the efficiency of the power conversion circuit.

[0061] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0062] The power conversion circuit and power supply system provided in the embodiments of the present application are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solutions and core ideas of the present application. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A power conversion circuit, characterized in that: The power conversion circuit comprises: A plurality of boost circuits, wherein a first port of each of the boost circuits is configured to transmit a corresponding first DC voltage, and second ports of the plurality of boost circuits are connected in parallel and configured to transmit a second DC voltage, wherein the first DC voltage is less than the second DC voltage; A single-stage inverter, wherein a first port of the single-stage inverter is connected to a second port of each of the boost circuits, and the second port of the single-stage inverter is configured to transmit alternating current.

2. The power conversion circuit according to claim 1, characterized in that: Each of the boost circuits comprises: a first inductor, wherein a first end of the first inductor is configured as a positive electrode of a first port of the boost circuit; a first switch tube, wherein a first electrode of the first switch tube is connected to a second end of the first inductor, and a second electrode of the first switch tube is configured as a positive electrode of a second port of the boost circuit; A second switch tube, wherein the first electrode of the second switch tube is connected to the first electrode of the first switch tube and the second end of the first inductor, and the second electrode of the second switch tube is configured as the negative electrode of the first port of the boost circuit and the negative electrode of the second port of the boost circuit.

3. The power conversion circuit according to claim 2, characterized in that: The switching state of the first switch tube and the switching state of the second switch tube are used to control the boost circuit to operate at a maximum power point.

4. The power conversion circuit according to claim 1, characterized in that: The single-stage inverter comprises: A DC side bridge circuit, wherein a first port of the DC side bridge circuit is connected to a second port of each of the boost circuits; an AC transformer circuit, wherein a first port of the AC transformer circuit is connected to a second port of the DC side bridge circuit; An AC side bridge circuit, wherein a first port of the AC side bridge circuit is connected to a second port of the AC transformer circuit, and the second port of the AC side bridge circuit is configured to transmit the AC power.

5. The power conversion circuit according to claim 4, characterized in that: The DC side bridge circuit comprises: a third switch tube, wherein a first electrode of the third switch tube is configured as a positive electrode of a first port of the DC side bridge circuit; a fourth switch tube, wherein a first electrode of the fourth switch tube is connected to a second electrode of the third switch tube, and the second electrode of the fourth switch tube is configured as a negative electrode of the first port of the DC side bridge circuit; a fifth switch tube, wherein a first electrode of the fifth switch tube is connected to a first electrode of the third switch tube; a sixth switch tube, wherein a first electrode of the sixth switch tube is connected to a second electrode of the fifth switch tube, and a second electrode of the sixth switch tube is connected to a second electrode of the fourth switch tube; Wherein, the first pole of the fourth switch tube and the first pole of the sixth switch tube are respectively configured as the first pole and the second pole of the second port of the DC side bridge circuit.

6. The power conversion circuit according to claim 5, characterized in that: The DC side bridge circuit also includes a first capacitor, a first end of the first capacitor is connected to the first electrode of the third switch tube, and a second end of the first capacitor is connected to the second electrode of the fourth switch tube.

7. The power conversion circuit according to claim 5, characterized in that: The AC transformer circuit comprises: A transformer, the transformer comprising a primary winding and a secondary winding; a second inductor, wherein a first end of the second inductor is connected to a second electrode of the third switch tube and a first end of the primary winding, and a second end of the second inductor is connected to a second electrode of the fifth switch tube and a second end of the primary winding; a third inductor, wherein a first end of the third inductor is connected to a first end of the secondary winding, and a second end of the third inductor is connected to a first pole of a first port of the AC-side bridge circuit; Wherein, the second end of the secondary winding is connected to the second pole of the first port of the AC side bridge circuit.

8. The power conversion circuit according to claim 7, characterized in that: The AC transformer circuit further includes a second capacitor, a first end of the second capacitor is connected to the second end of the secondary winding, and a second end of the second capacitor is connected to the second pole of the first port of the AC side bridge circuit.

9. The power conversion circuit according to claim 7 or 8, characterized in that: The AC side bridge circuit includes a first bridge arm and a second bridge arm connected in parallel, the midpoint of the first bridge arm serves as a first pole of a first port of the AC side bridge circuit, and the midpoint of the second bridge arm serves as a second pole of the first port of the AC side bridge circuit.

10. The power conversion circuit according to claim 9, characterized in that: The first bridge arm comprises: a seventh switch tube, wherein a first electrode of the seventh switch tube is connected to a first end of the second bridge arm; an eighth switch tube, wherein a first electrode of the eighth switch tube is connected to a second electrode of the seventh switch tube, and a second electrode of the eighth switch tube is connected to a second end of the third inductor; a ninth switch tube, wherein a first electrode of the ninth switch tube is connected to a second electrode of the eighth switch tube; A tenth switch tube, wherein a first electrode of the tenth switch tube is connected to a second electrode of the ninth switch tube, and a second electrode of the tenth switch tube is connected to a second end of the second bridge arm.

11. The power conversion circuit according to claim 10, characterized in that: The second bridge arm comprises: a third capacitor, wherein a first end of the third capacitor serves as a first end of the second bridge arm, and a second end of the third capacitor is connected to a second end of the secondary winding or a second end of the second capacitor; A fourth capacitor, wherein a first end of the fourth capacitor is connected to the second end of the third capacitor and serves as a midpoint of the second bridge arm, and a second end of the fourth capacitor serves as a second end of the second bridge arm.

12. The power conversion circuit according to claim 11, characterized in that: The third capacitor and the fourth capacitor are both microfarad-level capacitors or nanofarad-level capacitors.

13. The power conversion circuit according to claim 10, characterized in that: The second bridge arm comprises: an eleventh switch tube, wherein a first electrode of the eleventh switch tube is connected to a first electrode of the seventh switch tube and is configured as a first electrode of a second port of the AC-side bridge circuit; a twelfth switch tube, wherein a first electrode of the twelfth switch tube is connected to a second electrode of the eleventh switch tube, and a second electrode of the twelfth switch tube is connected to a second end of the secondary winding or a second end of the second capacitor; a thirteenth switch tube, wherein a first electrode of the thirteenth switch tube is connected to a second electrode of the twelfth switch tube; A fourteenth switch tube, wherein the first pole of the fourteenth switch tube is connected to the second pole of the thirteenth switch tube, the second pole of the fourteenth switch tube is connected to the second pole of the tenth switch tube and is configured as the second pole of the second port of the AC side bridge circuit.

14. A power supply system, characterized in that: The power supply system comprises: The power conversion circuit according to any one of claims 1 to 13; A plurality of photovoltaic components, each of which is connected to a first port of the boost circuit.

15. The power supply system according to claim 14, characterized in that: The power supply system further includes one or more batteries, each of which is connected in parallel to the second port of the boost circuit.

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