With asymmetry SVPWM ( Space Vector Pulse Width Modulation ) strategy the optimum switching frequency and the optimum sample deviation angle are given by analyzing the principle and performance of 4-step inverter. 以4通道逆变器为例,分析了不对称SVPWM方案的基本原理和性能,给出了最优的开关频率和采样偏移角。