软开关单相光伏并网逆变器原理及并网实验

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

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。

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.