新型三相PWM整流器无交流电压传感器控制方法

摘要

Since the virtual flux-based algorithm applied in three-phase PWM rectifier control without AC-voltage sensor may induce DC-offset error,an AC-voltage observer is developed.An orthogonal signal generator is constructed based on third-order generalized integrator,which tracks the sinusoidal signal of specified frequency without any static error.The AC-voltage on two-phase static coordinates is estimated for realizing the three-phase PWM rectifier control without AC-voltage sensors.Without differential operation of current signal and being insensitive to noise,the developed observer avoids the problems of pure integral operation.The grid voltage estimation applied in the observer is equivalent to grid voltage filtering,which ensures the input current waveform of rectifier is sinusoidal and has little harmonics.Simulative and experimental results verify the effectiveness of the developed observer.%针对三相脉冲宽度调制(PWM)整流器无交流电压传感器控制策略中,虚拟磁链定向算法会引入直流偏置误差的问题,研究了一种新的交流电压观测方法.利用三阶广义积分器能对特定频率正弦信号实现无静差跟踪的特性,构造正交信号发生器,对两相静止坐标系下的交流电压进行估算,实现三相PWM整流器无交流电压传感器的控制方法.该方法无需对电流信号进行微分运算,对噪音不敏感,且能避免纯积分运算存在的问题;采用该方法估算电网电压相当于对其进行了滤波处理,能够保证整流器输入电流波形正弦度好,谐波含量小.仿真和实验结果验证了所提方法的有效性.