Abstract：As a key component of the photovoltaic power generation system, the inverter significantly impacts the system’s stability. Traditional non-isolated single-phase inverters cannot perform buck-boost functions and have high leakage and large secondary ripple currents caused by pulsating power. This paper proposes a five-switch common-ground inverter with a power decoupling function to achieve buck-boost functionality. This topology solves the leakage current problem for common-ground topologies, decouples power in the mode, and incorporates secondary ripple suppression control to mitigate the inherent secondary ripple of single-phase inverters. Firstly, the proposed topology introduces a Boost converter based on the full-bridge converter to construct a compact and efficient design. The topology utilizes a minimal number of switching devices, i.e., five switches without diodes. Hence, the device reuse rate is enhanced, and the stability of the photovoltaic power generation system is ensured. The topology can achieve buck and boost functionalities by integrating the Boost converter, providing greater flexibility and adaptability to varying input conditions. Secondly, the paper delves into the mechanism and impact of secondary ripples. A detailed current path is planned to store the pulsating power in the intermediate capacitor, decoupling effective power without additional devices. The proposed secondary ripple suppression strategy further reduces the secondary ripple in the input current, ensuring smooth and stable operation. The need for large, bulky electrolytic capacitors in the DC link is eliminated, enhancing the system’s lifespan and reliability. Finally, a simulation model and experimental platform are built to verify the proposed topology and the control strategy under different power factors. The simulation and experimental results demonstrate that the proposed topology and control strategy significantly suppress the secondary ripple of DC current at unity power factors of PF=0.8 and PF=-0.8, greatly reducing the pulsation of DC current. The total harmonic distortion (THD) of the output voltage and current is maintained below 2.0%. When the inverter output power transitions from 500 W to 250 W and back to 500 W, the dynamic response time is approximately 0.65 s, with the voltage fluctuation of the intermediate capacitor not exceeding 40 V. The common-mode voltage is approximately 0 V, and the root mean square value of the leakage current is only 7.25 mA, meeting the safety standard DIN VDE 0126-1-1. At a rated power of 500 W, the maximum efficiency can reach 95.62%. The following conclusions can be drawn. (1) The proposed topology is compact without electrolytic capacitors. It has a wide input/output range and low leakage current, which is suitable for photovoltaic power generation systems. (2) The power decoupling function and the proposed control strategy effectively suppress the secondary ripple of DC current under different power factors. (3) Compared to existing research, the proposed topology achieves the most functions with the least number of devices.
陈贺驰, 杨江朋, 张恒鹏, 白方林, 舒泽亮. 具有功率解耦功能的五开关共地逆变器[J]. 电工技术学报, 2025, 40(18): 5988-5997.
Chen Hechi, Yang Jiangpeng, Zhang Hengpeng, Bai Fanglin, Shu Zeliang. Five-Switch Common Ground Inverter with Power Decoupling Function. Transactions of China Electrotechnical Society, 2025, 40(18): 5988-5997.
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