低采样率SPWM逆变器重复控制策略

摘要

The harmonic problem of sinusoidal pulse-width modulation (SPWM) inverter output can be well dealt with by traditional repetitive control, but the control system tends to be unstable at low sampling rate. In the field of using high power inverter, the switching frequency of power devices is always lower. So the sampling fre⁃quency of the control system is relatively lower. And there will be difficulties in traditional repetitive control applica⁃tion. The phase compensation in repetitive control is improved and fractional phase lead repetitive control is pro⁃posed. The stability margin of the system is improved and steady-state error is reduced by the method. Simulation re⁃sults show that fractional phase lead repetitive control has better stability.%对于传统的重复控制，虽然能够很好的解决SPWM逆变器输出谐波问题，但在低采样率时，控制系统不容易稳定。在大功率逆变器应用场合，功率器件的开关频率一般较低，因此控制系统的采样频率也相应较低。此时，传统的重复控制的应用将出现困难。文中将重复控制中的相位补偿环节进行改进，提出分数相位超前重复控制，该方案不仅扩大了系统的稳定裕度，还减小了稳态误差。仿真结果表明，分数相位超前重复控制具有更好的稳定性。