Dual-input high-gain DC-AC converter based on coupling inductor

Abstract

The invention discloses a dual-input high-gain DC-AC converter based on a coupling inductor, which adopts a coupling inductor bipolar boost unit and is combined with a bipolar converter structure, namely an input power supply and neutral point common ground structure, so that leakage current caused by parasitic capacitance of a photovoltaic panel is remarkably reduced, and output voltage ripples are effectively reduced. The electric energy conversion efficiency of the system is improved, the electric shock risk can be reduced, the protection performance is improved, the electromagnetic interference is reduced, and the operation of the system is more stable and safer; the influence of all parasitic parameters on the balance of the bipolar output voltage is eliminated, and the voltage balance can still be effectively kept under the condition that the parasitic parameters of the primary side and the secondary side of the coupling inductor are not matched; by reasonably optimizing the turn ratio design, the voltage gain is effectively improved, the dependence on the turn ratio of a specific transformer in the traditional design is eliminated, and the design of the converter is simpler and more flexible. Compared with a traditional high-gain DC-AC converter, the high-gain DC-AC converter has the advantages that the number of devices and the circuit complexity are reduced, the power loss is reduced, and the production cost is reduced. The self-balancing capability of the converter is also a bright spot, and even if one path is open, the bipolar output voltage difference can still be kept in an extremely small range, so that the efficient and stable operation of the system is ensured, and the converter has a wide application prospect.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, specifically to a dual-input high-gain DC-AC converter based on coupled inductors. Background Technology

[0002] In recent years, with the rapid increase in global energy demand and the increasing depletion of traditional fossil fuels, energy supply security faces unprecedented challenges. At the same time, the widespread use of traditional energy sources has led to increasingly serious environmental problems such as the greenhouse effect and air pollution, which have become a global focus. Especially with the intensification of global warming and environmental degradation, the development of a low-carbon economy and renewable energy has become an important strategic direction for governments and enterprises worldwide.

[0003] Against this backdrop, clean and renewable energy sources such as hydrogen and biomass energy have gradually become a research focus in the energy field due to their sustainability and environmental friendliness. Hydrogen energy, as a key representative, has attracted increasing attention from researchers and industry due to its high energy density, zero emissions, and broad application potential, particularly demonstrating tremendous development prospects in transportation, power generation, and energy storage.

[0004] Meanwhile, with the increasing global demand for green energy, especially in the efficient utilization of renewable energy, fuel cells and photovoltaic power generation, as typical clean energy technologies, are gradually being widely used. However, these energy systems face a significant challenge: their output voltage is generally low, making it difficult to directly connect them to bipolar DC microgrids or AC grid systems. Therefore, there is an urgent need for high-gain DC converters to achieve voltage boosting and power matching, ensuring that they can meet the requirements for grid connection.

[0005] In traditional high-gain converter designs, although higher voltage gain can be achieved by increasing the turns ratio of the coupled inductor windings or by using multi-stage stacking structures, these methods often introduce a series of problems, such as increased circuit complexity, increased number of components, increased power loss, and severe parasitic effects. These problems affect the system's efficiency and reliability. Furthermore, the complex structure and large number of components in traditional designs result in high maintenance and production costs, making it difficult to meet the demands of today's high-efficiency, high-reliability, and low-cost systems.

[0006] To address the above issues, Chinese Patent Publication No. CN105391287A discloses a zero-input current ripple high-gain converter based on dual-coupled inductors and a single switch. It includes a DC input power supply Vin, coupling inductors T1 and T2, freewheeling diodes D1, D2, and D4, an energy storage capacitor C1, a power switch Q, a clamping diode D3, voltage doubler energy storage capacitors C2, C3, and C4, an output diode D0, and an output capacitor C0. This converter achieves high voltage gain by utilizing the coupling inductors, and the gain is simultaneously controlled by the duty cycle and the wide adjustable range of the coupling inductor turns ratio, resulting in low voltage and current stress on the switch. Through coupling of the input inductor and the energy storage inductor, and with proper configuration of the coupling coefficient, zero input current ripple can be achieved. The lossless absorption circuit composed of the clamping diode and the energy storage capacitor reduces voltage spikes on the switch. An energy recovery circuit composed of the freewheeling diode, the voltage doubler energy storage capacitor, and the secondary side of the coupling inductor ultimately feeds back leakage inductance energy to the load side, improving the converter's efficiency.

[0007] For example, Chinese Patent CN116683741A discloses a dual-switch high-gain converter with a coupled inductor and its control method, belonging to the field of power electronics technology. The converter of this invention includes a dual-switch input terminal, a coupled inductor boost unit, and an output terminal. The dual-switch input terminal includes a power supply Vin, a first independent inductor L1, a second independent inductor L2, a first switch S1, and a second switch S2. The dual-switch input terminal is connected to the coupled inductor boost unit, which includes diodes D1 and D2, capacitors C1, C2, and C3, a primary winding np of the coupled inductor, and a secondary winding ns of the coupled inductor. The output terminal of the coupled inductor boost unit is connected to the anode of diode D3, and diode D3 and capacitor C4 constitute the output section of the converter. This invention has the advantages of simple topology, ultra-high output voltage gain, ultra-low switching voltage stress, convenient switching control, and high operating efficiency.

[0008] Currently, existing converter technology still has shortcomings: while both patents improve the reliability of converter operation to some extent, there are still deficiencies in high-voltage gain implementation, structural simplification, multi-input energy fusion, bipolar output voltage balancing, and leakage current suppression. These limitations make it difficult to simultaneously meet the performance, efficiency, and reliability requirements of bipolar DC microgrids and hybrid energy systems for DC-AC converters. The existing technology still needs improvement. Summary of the Invention

[0009] To address the shortcomings of existing technologies, this invention provides a dual-input high-gain DC-AC converter based on coupled inductors to solve the aforementioned problems.

[0010] To achieve the above objectives, the present invention provides the following technical solution: a dual-input high-gain DC-AC converter based on coupled inductors, mainly comprising: The first end of the primary winding L1 of the coupled inductor is connected to the positive input terminal, and the second end is connected to the second end of the switching transistor S1 and the first end of the switching transistor S2. The first end of the secondary winding L2 of the coupled inductor is connected to the first end of the capacitor C1 and the second end of the switching transistor S2. The second end of the capacitor C1 is connected to the cathode of the diode D4 and the anode of the diode D1 to form the negative input terminal. The cathode of the diode D1 is connected to the first end of the capacitor C2 and the anode of the diode D2. The second end of the capacitor C2 is connected to the second end of the secondary winding L2 of the coupled inductor and the first end of the capacitor C3. The second end of the capacitor C3 is connected to the anode of the diode D4 and the cathode of the diode D3. The anode of the diode D3 is connected to the second connection terminal of the output capacitor unit to form the second load terminal. The cathode of the diode D2 is connected to the first connection terminal of the output capacitor unit to form the first load terminal. When switch S1 is turned on, the input voltage stores energy in the primary winding L1 of the coupled inductor. The secondary winding L2 of the coupled inductor charges capacitors C1 and C2 through diode D1. Simultaneously, the secondary winding L2 and capacitor C3 of the coupled inductor charge the output capacitor Co1 through diode D3, thus acquiring transient current data under the dual-input port arrangement. After switch S1 is turned off, the secondary winding L2 of the coupled inductor freewheels until the current drops to zero. If the transient current data deviates from the dual-input port arrangement by more than a preset threshold, the transient current data and the port energy distribution deviation are fused through the information processing stage to obtain the port energy distribution correction coefficient. Based on the port energy distribution correction coefficient, an adaptive control algorithm is used to adjust the duty cycle of switch S2. When the current in the secondary winding L2 of the coupled inductor drops to zero, diode D1 turns off and diode D2 turns on. The primary winding L1 of the coupled inductor charges capacitor C1. The input voltage, the primary winding L1 of the coupled inductor, and the secondary winding L2 of the coupled inductor charge capacitor C3 through diode D4, thus determining the adjusted high-voltage gain parameters. From the adjusted high-voltage gain parameters, the power mismatch index under the series superposition of capacitor C2 and the charging path of output capacitor Co1 is obtained. If the power mismatch index exceeds the preset range, the waveform distortion compensation value under the freewheeling mode of the secondary winding is iteratively calculated using a particle swarm optimization algorithm to obtain the compensated output waveform data. Based on the compensated output waveform data, the dual-input port arrangement and transient current data are fused to determine whether the AC output of the half-bridge inverter meets the voltage clamping stability, and control commands to improve the freewheeling mode response capability of the secondary winding are obtained. Based on the control command to enhance the freewheeling mode response capability of the secondary winding, the conduction timing of switching transistors S1 and S2 is dynamically adjusted to determine the stable waveform of the high-gain DC output of the coupled inductor bipolar boost unit to the AC output of the half-bridge inverter under multiple energy inputs.

[0011] Furthermore, the secondary winding L2 of the coupled inductor and capacitor C3 charge the output capacitor Co1 through diode D3 to obtain transient current data under the dual-input port arrangement.

[0012] Furthermore, by integrating transient current data with port energy distribution deviation through information processing, a port energy distribution correction coefficient is obtained.

[0013] Furthermore, the primary winding L1 of the coupled inductor charges the capacitor C1, and the input voltage, along with the primary winding L1 and the secondary winding L2 of the coupled inductor, charges the capacitor C3 through the diode D4, thus determining the adjusted high-voltage gain parameters.

[0014] Furthermore, the waveform distortion compensation value under the secondary winding freewheeling mode is calculated iteratively using the particle swarm optimization algorithm to obtain the compensated output waveform data.

[0015] Furthermore, control commands are obtained to enhance the freewheeling mode response capability of the secondary winding.

[0016] Compared to existing technologies, the advantages of this invention are as follows: A dual-input high-gain DC-AC converter based on coupled inductors employs a coupled inductor bipolar boost unit, combined with a bipolar converter structure—that is, a common ground structure for the input power supply and neutral point—significantly reducing leakage current caused by the parasitic capacitance of the photovoltaic panel and effectively reducing output voltage ripple. This not only improves the system's power conversion efficiency but also reduces the risk of electric shock, enhances protection performance, reduces electromagnetic interference, and makes the system more stable and safer to operate. It eliminates the influence of all parasitic parameters on the bipolar output voltage balance, effectively maintaining voltage balance even when the parasitic parameters of the primary and secondary sides of the coupled inductor are mismatched. Through reasonable optimization of the turns ratio design, the voltage gain is effectively improved, eliminating the dependence on a specific transformer turns ratio in traditional designs, making the converter design simpler and more flexible. Compared with traditional high-gain DC-AC converters, it not only reduces the number of components and circuit complexity, but also reduces power loss and production costs. The converter's self-balancing capability is also a major highlight; even with one circuit open, the bipolar output voltage difference remains within a very small range, ensuring efficient and stable system operation. Attached Figure Description

[0017] Figure 1 This is a circuit schematic diagram of a dual-input high-gain DC-AC converter based on a coupled inductor according to the present invention. Figure 2 This is a circuit diagram of a boost unit submodule of a dual-input high-gain DC-AC converter based on coupled inductors according to the present invention; Figure 3 This is a first mode diagram of a dual-input high-gain DC-AC converter based on coupled inductors according to the present invention; Figure 4 This is a second mode diagram of a dual-input high-gain DC-AC converter based on coupled inductors according to the present invention; Figure 5 This is a third mode diagram of a dual-input high-gain DC-AC converter based on coupled inductors according to the present invention; Figure 6 This is the fourth mode diagram of a dual-input high-gain DC-AC converter based on coupled inductors according to the present invention; Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0019] This invention provides a technical solution: a dual-input high-gain DC-AC converter based on coupled inductors, comprising a coupled inductor bipolar boost unit and a half-bridge inverter, including the following steps: S101, construct the circuit topology of the coupled inductor bipolar boost unit and clarify the connection relationships between the components. Specifically, the first end of the primary winding L1 of the coupled inductor is connected to the positive input terminal, and its second end is connected to the second end of switching transistor S1 and the first end of switching transistor S2, thus forming the switching node on the primary side. On the secondary side, the first end of the secondary winding L2 of the coupled inductor is connected to the first end of capacitor C1 and the second end of switching transistor S2. The second end of capacitor C1 is connected to the cathode of diode D4 and the anode of diode D1, thus forming the negative input terminal.

[0020] Regarding the connection methods of other diodes and capacitors in the circuit, the cathode of diode D1 is connected to the first terminal of capacitor C2 and the anode of diode D2. The second terminal of capacitor C2 is connected to the second terminal of the secondary winding L2 of the coupled inductor and the first terminal of capacitor C3. The second terminal of capacitor C3 is connected to the anode of diode D4 and the cathode of diode D3. At the load output terminal, the anode of diode D3 is connected to the second connection terminal of the output capacitor unit to form the second load terminal, while the cathode of diode D2 is connected to the first connection terminal of the output capacitor unit to form the first load terminal. Through the above connection methods, the basic circuit architecture under multiple energy inputs is established.

[0021] S102: Acquire transient current data under dual-input port arrangement. This step mainly involves the energy transfer and data acquisition process during the conduction of switch S1. When switch S1 is in the conducting state, the input voltage directly acts on the primary winding L1 of the coupled inductor, causing it to begin storing energy. At the same time, the secondary winding L2 of the coupled inductor charges capacitors C1 and C2 respectively through the circuit formed by diode D1.

[0022] In a preferred embodiment, the energy transfer path of the circuit also includes the synergistic effect of the coupled inductor secondary winding L2 and capacitor C3, which charge the output capacitor Co1 through diode D3. During this dynamic process, the system monitors and acquires transient current data under the dual-input port arrangement in real time. This data reflects the transient response characteristics of the circuit under the current mode, providing data support for subsequent control strategy adjustments.

[0023] S103 processes the freewheeling current after the switch S1 is turned off and calculates a correction coefficient based on the data deviation. Specifically, after the switch S1 is turned off, the secondary winding L2 of the coupled inductor enters a freewheeling state until its current drops to zero. During this period, the system analyzes the transient current data obtained in step S102.

[0024] If the deviation between the monitored transient current data and the standard model of the dual-input port arrangement exceeds a preset threshold, it indicates that the current energy distribution or circuit response is abnormal or suboptimal. In this case, the transient current data and the port energy distribution deviation are fused through an information processing stage. This process aims to quantify the degree of influence of the deviation and calculate a port energy distribution correction coefficient, which will serve as a key parameter for subsequent adjustment of the switching transistor's operation.

[0025] S104: Based on the port energy distribution correction coefficient, an adaptive control algorithm is used to adjust the duty cycle of switch S2 and determine the adjusted high-voltage gain parameters. The core of this step is to use the correction coefficient calculated above to dynamically adjust the duty cycle of switch S2 through an adaptive control algorithm to optimize the circuit's energy transfer efficiency and stability.

[0026] In the specific evolution of the circuit mode, when the current in the secondary winding L2 of the coupled inductor drops to zero, diode D1 will turn off, while diode D2 will turn on. At this time, the circuit enters a new operating phase: the primary winding L1 of the coupled inductor begins to charge capacitor C1; simultaneously, the input voltage, the primary winding L1 of the coupled inductor, and the secondary winding L2 of the coupled inductor are connected in series, charging capacitor C3 through diode D4. Based on the voltage-current relationship under this mode, the system determines the adjusted high-voltage gain parameters to ensure that the system can maintain the expected boost effect under multiple energy inputs.

[0027] S105, based on the adjusted high-voltage gain parameters determined in step S104, further analyze the power transfer characteristics of the circuit. Specifically, obtain the power mismatch index under the series superposition state of capacitor C2 and the charging path of output capacitor Co1. This index reflects the difference between the actual power transfer and the theoretical expectation under the current high-gain state. If the power mismatch index is detected to exceed the preset allowable range, the system will initiate the optimization process. In this embodiment, a particle swarm optimization algorithm is used for iterative calculation to compensate for waveform distortion under the freewheeling mode of the secondary winding. Through iterative optimization of the algorithm, an accurate waveform distortion compensation value is calculated and applied to waveform generation to obtain the compensated output waveform data. This process ensures the quality and accuracy of the circuit output waveform under high-gain conditions.

[0028] S106 performs multi-dimensional fusion analysis and stability assessment on the compensated output waveform data. This step deeply fuses the compensated output waveform data obtained in the previous steps with the dual-input port arrangement information and transient current data. Through this comprehensive processing of multi-source data, the system can comprehensively evaluate the circuit's operating status. The core task is to determine whether the AC output of the half-bridge inverter meets the voltage clamping stability requirements. Voltage clamping stability is a key indicator for ensuring the safe operation of the inverter. Based on this assessment, the system generates control commands aimed at improving the freewheeling mode response capability of the secondary winding. These commands not only include corrections to the current state but also optimize the dynamic response characteristics under freewheeling mode, providing a decision-making basis for subsequent timing adjustments.

[0029] S107, Perform final timing adjustment and waveform determination. Based on the control command generated in step S106 to improve the freewheeling mode response capability of the secondary winding, the system dynamically and precisely adjusts the conduction timing of switching transistors S1 and S2. This adjustment is real-time and aims to eliminate deviations and instabilities identified in previous steps. By optimizing the conduction timing of the switching transistors, the performance of the coupled inductor bipolar boost unit under complex multi-energy input conditions is ensured. Finally, a stable waveform transmitted from the high-gain DC side to the AC side of the half-bridge inverter is determined and output. This step achieves smooth energy transfer from the DC boost stage to the AC inverter stage, ensuring high-gain output and waveform quality of the entire system under multi-energy input environments.

[0030] In the coupled inductor bipolar boost unit, the second end of the primary winding L1 of the coupled inductor is connected to the second end of the switching transistor S1 and the first end of the switching transistor S2. The first end of the primary winding L1 forms the positive input terminal of the coupled inductor bipolar boost unit. The first end of the secondary winding L2 of the coupled inductor is connected to the first end of the capacitor C1 and the second end of the switching transistor S2. The second end of the capacitor C1 is connected to the cathode of diode D4 and the anode of diode D1, which is the negative input terminal of the coupled inductor bipolar boost unit. The cathode of diode D1 is connected to the anode of diode D2 and the capacitor C1. The first terminal of capacitor C2, and the cathode of diode D2 connected to the first connection terminal of the output capacitor unit, form the first load terminal of the coupled inductor bipolar boost unit. The second terminal of capacitor C2 is connected to the second terminal of the secondary winding L2 of the coupled inductor and the first terminal of capacitor C3. The second terminal of capacitor C3 is connected to the anode of diode D4 and the cathode of diode D3. The anode of diode D3 is connected to the second connection terminal of the output capacitor unit, and the anode of diode D3 is connected to the second connection terminal of the output capacitor unit, forming the second load terminal of the coupled inductor bipolar boost unit. The dual-input single-output high-gain DC-AC inverter based on coupled inductors is characterized in that, within one operating cycle, the operating process sequentially includes four modes, wherein: First mode: Switch S1 is turned on, and the input voltage Vin stores energy in the primary winding L1 of the coupled inductor. The secondary winding L2 of the coupled inductor charges capacitors C1 and C2 through diode D1, and also charges capacitor C1 together with capacitor C3 through diode D3.

[0031] Second mode: When the switch S1 is just turned off, the current on the secondary winding L2 of the coupled inductor cannot immediately reach zero. It continues to flow in the original direction until the current drops to zero. The second mode ends and the third mode begins.

[0032] Third Mode: When the current on the secondary winding L2 of the coupled inductor drops to zero, diode D1 turns off, diode D2 turns on, and switch S2 turns on. The primary winding L1 of the coupled inductor charges capacitor C1. The input voltage Vin, the primary winding L1 of the coupled inductor, and the secondary winding L2 of the coupled inductor together charge capacitor C3 through diode D4. The input voltage Vin, the primary winding L1 of the coupled inductor, the secondary winding L2 of the coupled inductor, and capacitor C2 together charge output capacitor Co1 through diode D2. This continues until switch S2 turns off, ending the third mode and entering the fourth mode.

[0033] Fourth mode: When the switch S2 is just turned off, the current on the secondary winding L2 of the coupled inductor cannot immediately reach zero, but continues to flow in the original direction until the current drops to zero.

[0034] For the dual-input high-gain DC-AC converter based on coupled inductors, based on the four operating modes, we have: When switch S1 is on and S2 is off:

[0035] When switch S2 is on and S1 is off:

[0036] in This is the voltage across the primary winding of the coupled inductor in the first mode. This is the voltage across the secondary winding of the coupled inductor in the first mode. Input voltage, Capacitors The voltage across the terminals, where D is the duty cycle of the switching transistor S1. This represents the voltage across the primary winding of the coupled inductor in the third mode. This represents the voltage across the secondary winding of the coupled inductor in the third mode. Where is the output voltage, MCCM is the voltage gain, and N is the turns ratio of the primary winding L1 and the secondary winding L2 of the coupled inductor.

[0037] According to the above formulas, the dual-input high-gain DC-AC converter based on coupled inductors provided by this invention can optimize system performance through precise parameter design. In particular, when the duty cycle of the switching control signal is set within the range of 0 to 1, and the duty cycle is set to approximately 0.5, the difference between the output capacitors Co1 and Co2 is almost negligible. At this point, the output voltage ripple is extremely low, almost minimized, thereby significantly improving the system stability and output voltage smoothness.

[0038] To further optimize the output voltage ripple, this invention adjusts the duty cycle of the switching control signal to approximately 0.5, thereby keeping the output voltage ripple within a predetermined error range. Through this adjustment, the converter can effectively suppress output voltage ripple under different operating conditions, ensuring efficient and stable system operation and meeting the requirements for high-precision voltage output.

[0039] Furthermore, due to the unique topology of the dual-input high-gain DC-AC converter based on coupled inductors of this invention, its output capacitors Co1 and Co2 can be implemented using electrolytic capacitors, just like in conventional circuit designs. This design ensures that the converter has a low size and high capacitance even at high voltage output.

[0040] The output capacitors Co1 and Co2 of this invention can be replaced with CBB (Ceramic Bipolar Battery Capacitors) instead of traditional electrolytic capacitors. CBB capacitors offer advantages such as low voltage, small capacitance, and high frequency response, effectively reducing the size of the output capacitors and improving system reliability and lifespan. Simultaneously, CBB capacitors can further reduce output voltage ripple, enhancing the system's performance stability during long-term operation. Therefore, by employing CBB capacitors, this invention not only optimizes the converter's size design but also further improves the overall system efficiency and lifespan while maintaining high performance.

[0041] The converter features bipolar output and self-balancing output voltage. Even if one output capacitor is open, the output power can be almost completely balanced. In addition, it has a turns ratio of less than 1, and the closer it is to 1, the greater the gain.

[0042] The converter has two inputs, one to a photovoltaic cell and the other to a hydrogen fuel cell, which can effectively achieve power complementarity and suppress the output power ripple on the bipolar capacitor of the half-bridge inverter. Therefore, the output capacitor value is extremely small. CBB capacitors are used to improve the overall lifespan of the system. As a result, the system has the characteristics of small output capacitor value, small power ripple, and long service life.

[0043] The converter features bipolar output and two input ports, and has a center-grounded feature, which effectively suppresses the leakage current problem caused by the photovoltaic panel to ground.

[0044] The dual-input hybrid energy DC-AC converter mainly consists of a fuel cell module and a photovoltaic (PV) power generation module, with the upper part being the fuel cell-side circuit and the lower part being the PV power generation-side circuit. The PV module, through the introduction of a Maximum Power Point Tracking (MPPT) control strategy, can track the optimal operating point of the PV cells in real time, ensuring maximum utilization of solar energy. Its output power is prioritized for supplying the load R, thereby avoiding waste of renewable energy. The fuel cell module has stable and continuous power supply characteristics, capable of timely compensation when the PV power is insufficient, forming a continuous power supply capability for the load. For the load side, when the combined power of the fuel cell and PV power generation module is insufficient to meet the load demand, the system will automatically absorb energy from the grid side for compensation; conversely, when the combined output power exceeds the load demand, the excess energy is fed back to the grid through the inverter stage, achieving bidirectional energy flow and dynamic balance. This feature not only improves energy utilization efficiency but also enhances the system's compatibility with the grid.

[0045] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A dual-input high-gain DC-AC converter based on coupled inductors, characterized in that, The first end of the primary winding L1 of the coupled inductor is connected to the positive input terminal. The second end of the primary winding L1 of the coupled inductor is connected to the second end of the switching transistor S1 and the first end of the switching transistor S2. The first end of the secondary winding L2 of the coupled inductor is connected to the first end of the capacitor C1 and the second end of the switching transistor S2. The second end of the capacitor C1 is connected to the cathode of the diode D4 and the anode of the diode D1 to form the negative input terminal. The cathode of the diode D1 is connected to the first end of the capacitor C2 and the anode of the diode D2. The second end of the capacitor C2 is connected to the second end of the secondary winding L2 of the coupled inductor and the first end of the capacitor C3. The second end of the capacitor C3 is connected to the anode of the diode D4 and the cathode of the diode D3. The anode of the diode D3 is connected to the second connection terminal of the output capacitor unit to form the second load terminal. The cathode of the diode D2 is connected to the first connection terminal of the output capacitor unit to form the first load terminal. During the conduction of switch S1, the input voltage stores energy in the primary winding L1 of the coupling inductor, the secondary winding L2 of the coupling inductor charges capacitors C1 and C2 through diode D1, and the secondary winding L2 of the coupling inductor and capacitor C3 charge the output capacitor unit through diode D3. After the switch S1 is turned off, the secondary winding L2 of the coupled inductor continues to flow until the current in the secondary winding L2 drops to zero. Then, diode D1 turns off and diode D2 turns on, and the primary winding L1 of the coupled inductor charges capacitor C1. The input voltage, along with the primary winding L1 and the secondary winding L2 of the coupled inductor, charges capacitor C3 through diode D4. The capacitor C2, in series, then charges the output capacitor unit.

2. The dual-input high-gain DC-AC converter based on coupled inductors according to claim 1, characterized in that, During the conduction period of the switch S1, the following are included: Acquire transient current data under dual-input port arrangement; After the switch S1 is turned off, the secondary winding L2 of the coupled inductor continues to freewheel until the current drops to zero, including: Determine whether the deviation between transient current data and the dual-input port arrangement exceeds a preset threshold. Then, through information processing, fuse the transient current data and the port energy distribution deviation to obtain the port energy distribution correction coefficient.

3. The dual-input high-gain DC-AC converter based on coupled inductors according to claim 1, characterized in that, After the current in the secondary winding L2 of the coupled inductor drops to zero, diode D1 turns off and diode D2 turns on, including: The duty cycle of switch S2 is adjusted using an adaptive control algorithm based on the port energy distribution correction coefficient. The primary winding L1 of the coupled inductor charges capacitor C1. The input voltage, along with the primary winding L1 and the secondary winding L2 of the coupled inductor, charges capacitor C3 through diode D4. The adjusted high-voltage gain parameters are then determined.

4. The dual-input high-gain DC-AC converter based on coupled inductors according to claim 3, characterized in that, The capacitors C2, connected in series, charge the output capacitor unit, including: The power mismatch index of capacitor C2 in series superposition and output capacitor unit charging path is obtained from the adjusted high voltage gain parameter. The waveform distortion compensation value under the secondary winding freewheeling mode is calculated iteratively by particle swarm optimization algorithm to obtain the compensated output waveform data.

5. The dual-input high-gain DC-AC converter based on coupled inductors according to claim 4, characterized in that, The compensated output waveform data includes: By fusing the compensated output waveform data with the dual-input port arrangement and transient current data, it is determined whether the AC output of the half-bridge inverter meets the voltage clamping stability, and control commands are obtained to improve the freewheeling mode response capability of the secondary winding.

6. The dual-input high-gain DC-AC converter based on coupled inductors according to claim 1, characterized in that, The coupled inductor bipolar boost unit provides high-gain DC output to the half-bridge inverter under multiple energy inputs, including: Based on the control command to enhance the freewheeling mode response capability of the secondary winding, the conduction timing of switching transistors S1 and S2 is dynamically adjusted to determine the stable waveform of the high-gain DC output of the coupled inductor bipolar boost unit to the AC output of the half-bridge inverter under multiple energy inputs.

7. The dual-input high-gain DC-AC converter based on coupled inductors according to claim 5, characterized in that, The determination of whether the AC output of the half-bridge inverter meets the voltage clamping stability requirement includes: By integrating the compensated output waveform data, dual input port arrangement, and transient current data, control commands are generated to improve the freewheeling mode response capability of the secondary winding, and the conduction timing of switching transistors S1 and S2 is dynamically adjusted.

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