Staggered parallel high-gain DC-AC inverter for photovoltaic hydrogen production

Abstract

The invention discloses an interleaved parallel high-gain DC-AC (Direct Current-Alternating Current) inverter for photovoltaic hydrogen production, which comprises a first transformer, a second transformer, an interleaved parallel circuit, a dual three-port asymmetric boosted circuit and an inverter circuit, and is characterized in that a primary coil L1 of the first transformer and a primary coil L3 of the second transformer are connected in parallel; a secondary coil L2 of the first transformer and a secondary coil L4 of the second transformer are connected in series; the interleaving parallel circuit is used for interleaving and connecting the photovoltaic power supply Vin with the primary coil L1 of the first transformer and the primary coil L3 of the second transformer in parallel; the dual three-port asymmetric boost circuit is used for boosting the voltage output by the secondary coils of the first transformer and the second transformer and outputting asymmetric bipolar direct current; and the inverter circuit is used for converting the direct current output by the dual three-port asymmetric booster circuit into alternating current and outputting the alternating current to a hydrogen production power grid Vg. The converter is high in conversion efficiency and small in voltage fluctuation.

Description

Technical Field

[0001] The invention relates to an inverter, and in particular to an interleaved parallel high-gain DC-AC inverter for photovoltaic hydrogen production. Background Art

[0002] As energy crisis and environmental pollution become increasingly serious, new energy power generation technologies such as solar energy have become a hot topic of research. However, the quality of new energy power is poor and has strong randomness. Therefore, the use of new energy to produce hydrogen has become an important means of absorbing new energy. The application of photovoltaic hydrogen production technology is becoming more and more extensive, and how to improve the efficiency and stability of the inverter has become a key challenge. Usually, the photovoltaic voltage is raised to the high-voltage bus voltage required for grid connection, and then converted into alternating current by the inverter, which is transmitted to the hydrogen production plant through the transmission line to reduce transmission losses. Therefore, it is crucial to match the photovoltaic voltage with the grid-connected inverter.

[0003] The instability of the output current of the photovoltaic system may have an adverse effect on the photovoltaic hydrogen production electrolyzer. When considering the topology of the photovoltaic inverter, it is necessary not only to realize the basic boost function, but also to consider the overall conversion efficiency of the system and safe and reliable operation. Among them, safe and reliable operation is easily overlooked during the design process, especially after the photovoltaic components are installed and fixed, they will generate parasitic capacitance with the ground. When the photovoltaic system starts working, the parasitic capacitance will form a loop with the subsequent circuit, thereby generating common-mode current. When the parasitic capacitance is large, the common-mode current generated is also large. This situation may have a greater impact on the inverter circuit and even damage the circuit. Existing inverters are basically two-level DC converters. Some inverters use staggered Flyback + full-bridge power frequency flip topology to realize energy transfer to the grid. The full-bridge inverter has a large number of switch tubes, high cost, and the bus capacitor is a DC two-level structure. In addition, when the capacitor capacity of each module in the inverter is different and the inductor parameters of each module in the inverter are different, the bus voltage will be unbalanced. The bus voltage imbalance causes voltage fluctuations, and the inverter bus capacitor voltage ripple is large, resulting in a short inverter life. Some inverters are based on a single-phase full-bridge inverter topology with a symmetrical inductor configuration. This topology can eliminate common-mode leakage current by applying bipolar modulation, but it has the disadvantages of large harmonics and low conversion efficiency; and although unipolar modulation reduces the requirements for filters and has higher conversion efficiency, it has leakage current problems. It can be seen from this that the single-phase full-bridge inverter topology with a symmetrical inductor configuration, whether it is bipolar modulation or unipolar modulation, cannot meet the overall needs of practical applications. In summary, the existing inverters have the disadvantages of difficult voltage fluctuations and low conversion efficiency, which leads to limited hydrogen production efficiency. Summary of the invention

[0004] In view of the problems existing in the prior art, the purpose of the present invention is to provide a staggered parallel high-gain DC-AC inverter for photovoltaic hydrogen production with high conversion efficiency and small voltage fluctuation.

[0005] In order to achieve the above-mentioned purpose of the invention, the present invention provides a staggered parallel high-gain DC-AC inverter for photovoltaic hydrogen production, comprising: A first transformer and a second transformer, wherein the primary coil L1 of the first transformer and the primary coil L3 of the second transformer are connected in parallel, and the secondary coils are connected in series; An interleaved parallel circuit, used to connect the photovoltaic power source to the primary coil L1 of the first transformer and the primary coil L3 of the second transformer in an interleaved parallel manner respectively; A dual three-port asymmetric boost circuit is used to boost the voltage output by the secondary coils of the first transformer and the second transformer to output asymmetric bipolar direct current, including a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a seventh capacitor C7, an eighth capacitor C8, a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, and an eighth diode D8, wherein the first ends of the secondary coil L2 of the first transformer and the secondary coil L4 of the second transformer connected in series are respectively connected to the first ends of the second capacitor C2, the third capacitor C3, and the fourth capacitor C4, and the second ends of the series connection are respectively connected to the first capacitor C1, the fifth capacitor C5, the seventh capacitor C7, The first end of the eighth capacitor C8 is also connected to the cathode of the third diode D3 and the anode of the fifth diode D5, respectively; the second end of the second capacitor C2 is connected to the anode of the second diode D2; the cathode of the second diode D2 is connected to the anode of the first diode D1 and the second end of the first capacitor C1, respectively; the cathode of the first diode D1 is connected to the second end of the third capacitor C3 and the anode of the third diode D3, respectively; the second end of the fourth capacitor C4 is connected to the anode of the fourth diode D4 and the cathode of the fifth diode D5, respectively; the cathode of the fourth diode D4 is connected to the anode of the eighth diode D8 and the second end of the fifth capacitor C5, respectively; the cathode of the eighth diode D8 is connected to the second end of the seventh capacitor C7; and the second end of the eighth capacitor C8 is connected to the negative electrode of the photovoltaic power source; The inverter circuit is used to convert the direct current output by the dual three-port asymmetric boost circuit into alternating current and then output it to the hydrogen production grid.

[0006] Furthermore, the staggered parallel circuit includes a first switch tube S1 and a second switch tube S2, the drain of the first switch tube S1 is connected to the first end of the primary coil L1 of the first transformer, and the source is connected to the negative electrode of the photovoltaic power supply, the drain of the second switch tube S2 is connected to the first end of the primary coil L3 of the second transformer, and the source is connected to the negative electrode of the photovoltaic power supply, and the second ends of the primary coils of the first transformer and the second transformer are both connected to the positive electrode of the photovoltaic power supply.

[0007] Furthermore, the staggered parallel circuit also includes a clamping circuit, which includes a sixth diode D6, a seventh diode D7 and a sixth capacitor C6, the positive electrode of the sixth diode D6 is connected to the first end of the primary coil L1 of the first transformer, and the negative electrode is respectively connected to the positive electrode of the second diode D2 and the first end of the sixth capacitor C6, the positive electrode of the seventh diode D7 is connected to the first end of the primary coil L3 of the second transformer, and the negative electrode is respectively connected to the positive electrode of the second diode D2 and the first end of the sixth capacitor C6, and the second end of the sixth capacitor C6 is connected to the negative electrode of the photovoltaic power supply.

[0008] Furthermore, the inverter circuit includes a third switch tube T1, a fourth switch tube T2 and a filter inductor L f The drain of the third switch tube T1 is connected to the cathode of the eighth diode D8, the source of the third switch tube T1 is connected to the drain of the fourth switch tube T2, and the source of the third switch tube T1 is also connected to the cathode of the eighth diode D8 through the filtering inductor L f One end of the hydrogen production grid is connected, the source of the fourth switch tube T2 is connected to the negative electrode of the photovoltaic power supply, and the other end of the hydrogen production grid is connected to the first end of the seventh capacitor C7.

[0009] Further, the gate of the first switch tube S1 inputs a first PWM control wave signal, the gate of the second switch tube S2 inputs a second PWM control wave signal, the first PWM control wave signal is used to control the switching of the first switch tube S1, and the second PWM control wave signal is used to control the switching of the second switch tube S2. The gate of the third switch tube T1 inputs a third PWM control wave signal, the gate of the fourth switch tube T2 inputs a fourth PWM control wave signal, the third PWM control wave signal is used to control the switching of the third switch tube T1, and the fourth PWM control wave signal is used to control the switching of the fourth switch tube T2. The duty ratios of the first PWM control wave signal and the second PWM control wave signal are both 0.6.

[0010] Furthermore, the turns ratio between the primary coil L1 and the secondary coil L2 of the first transformer is 1, and the turns ratio between the primary coil L3 and the secondary coil L3 of the second transformer is 1.

[0011] Furthermore, the first switch tube S1 and the second switch tube S2 are both NMOS tubes. The third switch tube T1 and the fourth switch tube T2 are both NMOS tubes.

[0012] Compared with the prior art, the present invention has the following beneficial effects: the input part of the present invention adopts an interlaced parallel structure, which can better adapt to the occasion of low voltage and high current input. The present invention has five boost circuits, among which when S1 is turned on and S2 is turned off, three boost units are charged, and the other two boost units are discharged at the same time. When S2 is turned on and S1 is turned off, two boost units are charged, and the other three boost units are discharged at the same time. The two cooperate with each other for alternating control, and control their respective boost units respectively, with high power conversion efficiency and high gain. The interlaced parallel structure can make the two-phase power evenly distributed, the single-channel power is small, the current is small, the inductance is small, it is suitable for high power, and the input current ripple is small; the dual three-port asymmetric boost circuit improves the voltage gain, realizes asymmetric bipolarity for the inverter, realizes the suppression of leakage current through the output capacitor C8, and the device voltage stress is small. The voltage difference between the two output capacitors is small and constant, and the voltage difference is independent of the turns ratio, which is conducive to the suppression of leakage current. The secondary coil is connected in series to offset the influence of parasitic parameters. The present invention can effectively expand the input voltage range and reduce current fluctuations, thereby improving the overall performance of the system and ensuring the high efficiency and stability of the photovoltaic hydrogen production process. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 An electrical schematic diagram of an interleaved parallel high-gain DC-AC inverter for photovoltaic hydrogen production provided by an embodiment of the present invention; Figure 2 is an electrical schematic diagram of an interleaved parallel circuit in an embodiment of the present invention; Figure 3 1 is an electrical schematic diagram of a dual three-port asymmetric boost circuit according to an embodiment of the present invention; Figure 4 This is an electrical schematic diagram of an embodiment of the present invention when working in mode 1; Figure 5 This is an electrical schematic diagram of an embodiment of the present invention when working in mode 2; Figure 6 This is an electrical schematic diagram of an embodiment of the present invention when working in mode 3; Figure 7 This is an electrical schematic diagram of an embodiment of the present invention when working in mode 4; Figure 8 This is an electrical schematic diagram of an embodiment of the present invention when working in mode 5; Fig. 9 This is an electrical schematic diagram of an embodiment of the present invention when working in mode 6. DETAILED DESCRIPTION

[0014] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0015] The invention provides a high-gain DC-AC inverter for photovoltaic hydrogen production, such as Figure 1 As shown, it includes a first transformer, a second transformer, an interleaved parallel circuit, a dual three-port asymmetric boost circuit and an inverter circuit. The primary coil L1 of the first transformer is connected in parallel with the primary coil L3 of the second transformer, and the secondary coil L2 of the first transformer is connected in series with the secondary coil L4 of the second transformer; the interleaved parallel circuit includes a first switch tube S1 and a second switch tube S2, which are used to switch the photovoltaic power source V in The dual three-port asymmetric boost circuit includes a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a seventh capacitor C7, an eighth capacitor C8, a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, and an eighth diode D8, which are used to boost the voltage output by the secondary coils of the first transformer and the second transformer and output asymmetric bipolar direct current; the inverter circuit includes a third switch tube T1, a fourth switch tube T2 and a filter inductor L f , used to convert the DC power output by the dual three-port asymmetric boost circuit into AC power and output it to the hydrogen production grid V g .

[0016] like Figure 1 and Figure 2 As shown, in the staggered parallel circuit, the drain of the first switch tube S1 is connected to the first end of the primary coil L1 of the first transformer, and the source is connected to the negative electrode of the photovoltaic power supply. The drain of the second switch tube S2 is connected to the first end of the primary coil L3 of the second transformer, and the source is connected to the negative electrode of the photovoltaic power supply. The second ends of the primary coil L1 of the first transformer and the primary coil L3 of the second transformer are both connected to the positive electrode of the photovoltaic power supply.

[0017] In addition, in order to obtain a better effect, the staggered parallel circuit may further include a clamping circuit, which includes a sixth diode D6, a seventh diode D7 and a sixth capacitor C6, wherein the anode of the sixth diode D6 is connected to the first end of the primary coil L1 of the first transformer, and the cathode is respectively connected to the anode of the second diode D2 and the first end of the sixth capacitor C6, the anode of the seventh diode D7 is connected to the first end of the primary coil L3 of the second transformer, and the cathode is respectively connected to the anode of the second diode D2 and the first end of the sixth capacitor C6, and the second end of the sixth capacitor C6 is connected to the cathode of the photovoltaic power source. The cathode of the sixth diode D6 serves as the first output terminal P1 of the staggered parallel circuit, the cathode of the seventh diode D7 serves as the second output terminal P2 of the staggered parallel circuit, and the cathode of the photovoltaic power source serves as the third output terminal P3 of the staggered parallel circuit.

[0018] like Figure 1 and Figure 3As shown, the dual three-port asymmetric boost circuit includes a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a seventh capacitor C7, an eighth capacitor C8, a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, and an eighth diode D8, wherein the first ends of the secondary coil L2 of the first transformer and the secondary coil L4 of the second transformer connected in series are respectively connected to the first ends of the second capacitor C2, the third capacitor C3, and the fourth capacitor C4, and the second ends of the series connection are respectively connected to the first ends of the first capacitor C1, the fifth capacitor C5, the seventh capacitor C7, and the eighth capacitor C8, and are also respectively connected to the third and second The cathode of the fourth diode D4 is connected to the anode of the eighth diode D8 and the second end of the fifth capacitor C5, the cathode of the eighth diode D8 is connected to the second end of the seventh capacitor C7, and the second end of the eighth capacitor C8 is connected to the negative electrode of the photovoltaic power source. Among them, the second end of the second capacitor C2 serves as the input terminal P4 and is connected to P1, the anode of the second diode D2 serves as the input terminal P5 and is connected to P2, the second end of the eighth capacitor C8 serves as the input terminal P6 and is connected to P3, the cathode of the eighth diode D8 serves as the output terminal P7, the first end of the eighth capacitor C8 serves as the output terminal P8, and the second end of the eighth capacitor C8 serves as the output terminal P9.

[0019] like Figure 1 As shown, the inverter circuit includes a third switch tube T1, a fourth switch tube T2 and a filter inductor L f The drain of the third switch tube T1 is connected to the cathode of the eighth diode D8, that is, the output terminal P7, the source of the third switch tube T1 is connected to the drain of the fourth switch tube T2, and the source of the third switch tube T1 is also connected to the cathode of the eighth diode D8, that is, the output terminal P7. f One end of the hydrogen production grid is connected, the source of the fourth switch tube T2 is connected to the negative electrode of the photovoltaic power supply, that is, the output end P9, and the other end of the hydrogen production grid is connected to the first end of the eighth capacitor C8, that is, the output end P8.

[0020] Among them, the gate of the first switch tube S1 inputs the first PWM control wave signal, and the gate of the second switch tube S2 inputs the second PWM control wave signal. The gate of the third switch tube T1 inputs the third PWM control wave signal, and the gate of the fourth switch tube T2 inputs the fourth PWM control wave signal. The four PWM control wave signals are all input through an external drive circuit to control the switching of the corresponding switch tubes, and the duty cycle of the first PWM control wave signal and the second PWM control wave signal is 0.6. In the topological structure of the conventional converter, the working range of the duty cycle D of the PWM control wave signal of the switch tube S1 and the switch tube S2 is 0.5-1, and the voltage gain is low when the duty cycle D is slightly greater than 0.5. However, due to the optimization of the topological structure, the present invention has a working range of the duty cycle D of the PWM control wave signal of S1 and S2 of 0-1, and has high gain in the full range. Compared with the conventional topological structure, the working range of the duty cycle D is broadened, and the voltage gain can be effectively improved. When the duty cycle of S1 and S2 is 0.6, and the two pulses maintain a certain phase difference, at least one switch tube in the circuit can always be maintained in the on state.

[0021] The first switch tube S1 and the second switch tube S2 are both NMOS tubes. The third switch tube T1 and the fourth switch tube T2 are both NMOS tubes.

[0022] In addition, a turns ratio between the primary coil L1 and the secondary coil L2 of the first transformer is 1, and a turns ratio between the primary coil L3 and the secondary coil L4 of the second transformer is 1.

[0023] When S1 is turned on and S2 is turned off, D3, C3, L2, and L4 constitute a boost unit, D4, C4, C5, L2, and L4 constitute a boost unit, and D2, C1, C2, L2, and L4 constitute a boost unit; when S2 is turned on and S1 is turned off, D1, C1, C3, L2, and L4 constitute a boost unit, and D5, C4, L2, and L4 constitute a boost unit.

[0024] Working principle of the present invention: In the working mode, it is divided into 6 modes, as follows: like Figure 4 As shown, mode 1 [t0-t1]: At t0, S1 is turned on and S2 is turned off. Diodes D7, D2, D3, and D4 are turned on, and diodes D6, D1, D5, and D8 are reverse cutoff. The energy in the leakage inductance between L3 and L4 is transferred to C6. As the leakage inductance energy decreases, the current of D7 gradually decreases. L2 and L4 charge C3 through D3, and charge C5 through D4 together with C4, and charge C2 through D2 together with C1. C7 and C8 are the hydrogen production grid V g When the S2 opening signal comes at time t1, the first mode ends.

[0025] like Figure 5 As shown, mode 2 [t1-t2]: At t1, S2 is turned on. Since L2 and L4 on the secondary side are coupled in opposite directions, the voltages of L2 and L4 cancel each other out and are in the current continuous flow state, and the current begins to gradually decrease. At t2, when the current continuous flow of L2 and L4 ends, the second mode ends.

[0026] like Figure 6 As shown, mode 3 [t2-t3]: At t2, the freewheeling of L2 and L4 ends, and diodes D2, D3, and D4 are naturally turned off. S1 and S2 remain turned on. In this mode, all diodes are cut off due to reverse voltage. In this mode, C7 and C8 continue to supply power to the load. At t3, when the S1 shutdown signal comes, the third mode ends.

[0027] like Figure 7 As shown, mode 4 [t3-t4]: at t3, S1 is turned off and S2 remains on. Diodes D7, D2, D3, and D4 are cut off due to reverse voltage. D6 is turned on, and the energy of C6 increases. L2 and L4 charge C4 through D5, and charge C1 through D1 together with C3, and also supply power to the hydrogen production grid through D8 together with C2 and C5. At t4, when the S1 opening signal comes, the fourth mode ends.

[0028] like Figure 8 As shown, mode 5 [t4-t5]: At t4, S1 is turned on. Since L2 and L4 are coupled in opposite directions, the voltages of L2 and L4 cancel each other out and are in the current continuous flow state. The current begins to decrease gradually. At t5, when the current continuous flow of L2 and L4 ends, the fifth mode ends.

[0029] like Fig. 9 As shown, mode 6 [t5-t6]: at t5, L2 and L4 freewheeling ends, and diodes D1, D5, and D8 are naturally turned off. S1 and S2 remain on. In this mode, all diodes are cut off due to reverse voltage. In this mode, C7 and C8 continue to supply power to the load. At t6, when the S2 shutdown signal comes, the sixth mode ends.

[0030] In all modal analyses, because the frequencies of T1 and T2 are set much lower than those of S1 and S2, the switching states of T1 and T2 remain unchanged for a long time and have no effect on the circuit. Therefore, the switching states of T1 and T2 are not analyzed in the above modes.

[0031] Based on the modal analysis, the expression of the voltage gain of the inverter is further derived.

[0032] Sixth capacitor C The voltage of 6 is equal to the output voltage of the Boost converter.C 6 Voltage for: , Where V in is the photovoltaic power supply voltage, D is S 1 duty cycle.

[0033] During Mode 1, S 1 is in the open state, S 2 is in the off state.

[0034] , , In the formula, are the voltages of L1, L2, L3, and L4 during mode 1, respectively; N1 and N2 are the turns ratios of the first transformer and the second transformer, respectively; K is the coupling coefficient of the primary coil and the secondary coil; in this embodiment, the coupling coefficients of the two transformers are the same, both K.

[0035] During Mode 1, the capacitor C 1. C 2. C 3. C 4. C 5 and the secondary coil L 2 and L 4 Write the expression of Kirchhoff's voltage law and you can get the capacitance C 2. C 3 Voltage and Capacitance C The voltage expression of 5 is as follows: , , , In the formula, They are C 1. C 2. C 3. C 4. C 5 voltage.

[0036] During Mode 2, the capacitor C 1. C 6. C 8 Write the expression of Kirchhoff's voltage law, and we can get C 8 Voltage as follows: .

[0037] During Mode 4, S2 is in the open state, S 1 is in the off state, L 2 and L 4 The voltages are as follows: , In the formula, They represent the voltages of L1, L2, L3, and L4 during mode 4, respectively.

[0038] During Mode 4, the capacitor C 1. C 2. C 3. C 4. C 5. C 7 and L 2 and L 4 Write the expression of Kirchhoff's voltage law and you can get the capacitance C 1. C 4 voltage and capacitance C The voltage expression of 7 is as follows: , In the formula, express C 7 voltage.

[0039] Combining the above expressions, we can get the capacitance C 7. C The voltage expression of 8 is: .

[0040] During Mode 6, the capacitor C 7. C 8 and the expression of Kirchhoff's voltage law for the hydrogen production grid, the voltage of the hydrogen production grid, i.e. the inverter output voltage Vo, is obtained as: .

[0041] The inverter voltage gain M expression is: .

[0042] It can be seen from the above formula that the inverter of the present application can achieve high voltage gain under the condition of extreme duty cycle. As the turns ratio N increases, the voltage gain of the inverter will be greatly improved.

[0043] When analyzing the voltage stress between semiconductor devices of the inverter of this application, it is considered that N1=N2=N, and K= 1. According to the analysis, S 1. S 2 Voltage stress Both C 6 are equal, as shown in the following equation: .

[0044] When the turns ratio N is greater than 1, S 1. S 2 Voltage stress The absolute value is lower than 1 / 5 of the output voltage. Therefore, the inverter can select a switching device with a lower rated voltage, which usually has a lower on-state resistance. R DS(ON) .

[0045] exist D 1 and D 3 are in the off state, D 1. D 3. Voltage stress, Equal, the expression is: .

[0046] exist D 6 and D 7 are in the off state, D 6 and D 7. Voltage stress Equal, the expression is: .

[0047] exist D 4. D 5 are in the off state, the diode D 4. D 5. Voltage stress Equal, the expression is: .

[0048] From the voltage stress analysis of semiconductor devices, it can be seen that the highest voltage stress of the diode in the inverter of the present application is still much lower than the output voltage. The inverter of the present application has the advantage of low voltage stress of semiconductor devices.

[0049] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Unless otherwise clearly specified and limited, "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0050] It should be understood that the above embodiments and descriptions only describe the principles, main features and advantages of the present invention. Without departing from the spirit and scope of the present invention, the present invention may be subject to various changes and improvements, and these changes and improvements all fall within the scope of protection of the present invention.

Claims

1. A high-gain DC-AC inverter for photovoltaic hydrogen production, characterized in that: include: A first transformer and a second transformer, wherein the primary coil L1 of the first transformer and the primary coil L3 of the second transformer are connected in parallel, and the secondary coil L2 of the first transformer and the secondary coil L4 of the second transformer are connected in series; An interleaved parallel circuit, used to connect the photovoltaic power source to the primary coil L1 of the first transformer and the primary coil L3 of the second transformer in an interleaved parallel manner respectively; A dual three-port asymmetric boost circuit is used to boost the voltage output by the secondary coils of the first transformer and the second transformer to output asymmetric bipolar direct current, including a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a seventh capacitor C7, an eighth capacitor C8, a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, and an eighth diode D8, wherein the first ends of the secondary coil L2 of the first transformer and the secondary coil L4 of the second transformer connected in series are respectively connected to the first ends of the second capacitor C2, the third capacitor C3, and the fourth capacitor C4, and the second ends of the series connection are respectively connected to the first capacitor C1, the fifth capacitor C5, the seventh capacitor C7, The first end of the eighth capacitor C8 is also connected to the cathode of the third diode D3 and the anode of the fifth diode D5, respectively; the second end of the second capacitor C2 is connected to the anode of the second diode D2; the cathode of the second diode D2 is connected to the anode of the first diode D1 and the second end of the first capacitor C1, respectively; the cathode of the first diode D1 is connected to the second end of the third capacitor C3 and the anode of the third diode D3, respectively; the second end of the fourth capacitor C4 is connected to the anode of the fourth diode D4 and the cathode of the fifth diode D5, respectively; the cathode of the fourth diode D4 is connected to the anode of the eighth diode D8 and the second end of the fifth capacitor C5, respectively; the cathode of the eighth diode D8 is connected to the second end of the seventh capacitor C7; and the second end of the eighth capacitor C8 is connected to the negative electrode of the photovoltaic power source; The inverter circuit is used to convert the direct current output by the dual three-port asymmetric boost circuit into alternating current and then output it to the hydrogen production grid.

2. The interleaved parallel high-gain DC-AC inverter for photovoltaic hydrogen production according to claim 1 is characterized in that: The staggered parallel circuit includes a first switch tube S1 and a second switch tube S2, wherein the drain of the first switch tube S1 is connected to the first end of the primary coil L1 of the first transformer, and the source is connected to the negative electrode of the photovoltaic power supply, the drain of the second switch tube S2 is connected to the first end of the primary coil L3 of the second transformer, and the source is connected to the negative electrode of the photovoltaic power supply, and the second ends of the primary coil L1 of the first transformer and the primary coil L3 of the second transformer are both connected to the positive electrode of the photovoltaic power supply.

3. The interleaved parallel high-gain DC-AC inverter for photovoltaic hydrogen production according to claim 2 is characterized in that: The staggered parallel circuit also includes a clamping circuit, which includes a sixth diode D6, a seventh diode D7 and a sixth capacitor C6. The positive electrode of the sixth diode D6 is connected to the first end of the primary coil L1 of the first transformer, and the negative electrode is respectively connected to the positive electrode of the second diode D2 and the first end of the sixth capacitor C6. The positive electrode of the seventh diode D7 is connected to the first end of the primary coil L3 of the second transformer, and the negative electrode is respectively connected to the positive electrode of the second diode D2 and the first end of the sixth capacitor C6. The second end of the sixth capacitor C6 is connected to the negative electrode of the photovoltaic power supply.

4. The interleaved parallel high-gain DC-AC inverter for photovoltaic hydrogen production according to claim 1, characterized in that: The inverter circuit includes a third switch tube T1, a fourth switch tube T2 and a filter inductor L f The drain of the third switch tube T1 is connected to the cathode of the eighth diode D8, the source of the third switch tube T1 is connected to the drain of the fourth switch tube T2, and the source of the third switch tube T1 is also connected to the cathode of the eighth diode D8 through the filtering inductor L f One end of the hydrogen production grid is connected, the source of the fourth switch tube T2 is connected to the negative electrode of the photovoltaic power supply, and the other end of the hydrogen production grid is connected to the first end of the seventh capacitor C7.

5. The interleaved parallel high-gain DC-AC inverter for photovoltaic hydrogen production according to claim 2, characterized in that: The gate of the first switch tube S1 inputs a first PWM control wave signal, and the gate of the second switch tube S2 inputs a second PWM control wave signal. The first PWM control wave signal is used to control the switching of the first switch tube S1, and the second PWM control wave signal is used to control the switching of the second switch tube S2.

6. The interleaved parallel high-gain DC-AC inverter for photovoltaic hydrogen production according to claim 4, characterized in that: The gate of the third switch tube T1 inputs a third PWM control wave signal, the gate of the fourth switch tube T2 inputs a fourth PWM control wave signal, the third PWM control wave signal is used to control the switching of the third switch tube T1, and the fourth PWM control wave signal is used to control the switching of the fourth switch tube T2.

7. The interleaved parallel high-gain DC-AC inverter for photovoltaic hydrogen production according to claim 5, characterized in that: The duty cycle of the first PWM control wave signal and the second PWM control wave signal are both 0.

6.

8. The interleaved parallel high-gain DC-AC inverter for photovoltaic hydrogen production according to claim 1, characterized in that: The turns ratio between the primary coil L1 and the secondary coil L2 of the first transformer is 1, and the turns ratio between the primary coil L3 and the secondary coil L3 of the second transformer is 1.

9. The interleaved parallel high-gain DC-AC inverter for photovoltaic hydrogen production according to claim 2, characterized in that: The first switch tube S1 and the second switch tube S2 are both NMOS tubes.

10. The interleaved parallel high-gain DC-AC inverter for photovoltaic hydrogen production according to claim 4, characterized in that: The third switch tube T1 and the fourth switch tube T2 are both NMOS tubes.

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