软开关单相光伏并网逆变器原理及并网实验

为了优化效率及提升功率密度,提出了一种采用MOSFET的软开关单相光伏并网逆变器及零电压调制方法。介绍了软开关单相并网逆变器的工作原理,通过零电压调制方法控制辅助谐振电路,实现MOSFET的零电压开通,并抑制MOSFET体二极管的反向恢复。因此,逆变器等效开关频率为100 k Hz,并网滤波电感减小。组建了一个30 kW光伏并网发电系统,对10台3 kW软开关单相光伏并网逆变器进行光伏发电测试,验证理论分析及可靠性。

Principle of Soft-switching Single-phase Grid-connected PV Inverter and Grid-connected Test

To optimize the efficiency and improve the power density, a soft-switching single-phase grid-connected photovoltaic(PV) inverter based on MOSFET and its zero-voltage switching sinusoidal pulse width modulation(ZVS SPWM) method were proposed. The operation principle of the soft-switching single-phase grid-connected converter was introduced. Using the zero-voltage modulation method, the auxiliary resonant circuit was controlled, thus realizing the zero-voltage switching of MOSFET and the suppression of reverse recovery of its body-diode. The switching frequency of the inverter was 100 kHz, thus the grid-connected filter inductance was reduced. A 30 kW grid-connected PV generation system was built, and a PV generation test was conducted on ten 3 kW soft-switching single-phase grid-connected PV inverters, which verified the theoretical analysis and the reliability of the generation system.