四开关空间矢量脉宽调制控制算法及母线电容电压不平衡问题的研究

Study on Four Switch SVPWM Control Algorithm and Problem of Unbalance Voltage of Capacitor in DC-Link

三相四开关逆变器采用"五段式"空间矢量脉宽调制(SVPWM)方案可有效减小电机的转矩脉动,而四开关逆变器的母线电容电压不平衡将直接影响SVPWM的效果,导致电机三相电流不平衡,使电机的转矩脉动加剧。在深入分析四开关逆变器SVPWM原理的前提下,分析了直流母线电压不平衡对电机运行的影响,提出了一种有效的补偿办法。仿真结果表明,补偿后的异步电机VVVF系统具有较好的性能。

The four-switch three-phase inverter only have four basic voltage space vector, The method of five-segment mode can reduce the torque ripple effectively, but the DC-link capacitor voltage unbalance of four-switch inverter will affect the effect the SVPWM directly and cause the three-phase current unbalance of the motor and intensify the torque ripple of the motor. Based on the analysis of the principle of four-switch SVPWM analysis the affect of the DC-link voltage unbalance on the motor, propose a effective compensation method. The simulations results showed that with the compensation the Induction motor VVVF system had a better performance.