三相电压型PWM整流器改进的不平衡控制策略

Improved Unbalanced Control Scheme for Three-phase Voltage Source PWM Rectifiers

提出一种静止α,β坐标系中三相电压型脉宽调制(PWM)整流器改进型电流不平衡控制算法。与原有的调节网侧瞬时有功功率不同,改进型方法考虑到交流侧功率损耗,通过调节整流器侧瞬时有功功率使输入电流谐波含量和输出纹波电压达到最小化。两种方法在α,β坐标系中直接产生参考电流时,无需锁相环和坐标变换,对正、负序电流分量也无需独立控制,而是采用比例谐振(PR)调节器实现电流控制。仿真和实验结果表明,即使在电压跌落严重的情况下,改进型控制方法比原有方法在控制直流侧输出电压纹波、输入电流总谐波含量(THD)、功率因数方面的性能更好。

A improved current control scheme in α,β stationary frame for three-phase voltage source pulse width modulation（PWM） rectifier operating under unbalanced voltage dip condition is proposed.Different from original current control scheme which regulates the instantaneous active power at the input source side,the improved current control scheme regulates the instantaneous active power at the converter poles considering the AC inductor power loss to minimize the harmonics of the input currents and the output voltage ripple.When implementing the development of the improved current-reference generator direcdy in α,β stationary frame,two schemes allow using proportional resonant（PR） controller for simultaneous compensation of both positive and negative current sequence components without phase-locked loop strategies and coordinate transformations,not controlled independendy.Simulation and experimental results indicate that the improved current control scheme has better performance in controlling DC-link voltage ripple,total harmonic distortion（THD） of input currents and power factor compared with the original scheme.