用于逆变器电流谐波抑制的改进的重复控制

Improved repetitive control for inverter current harmonics suppression

重复控制被广泛应用在电流谐波抑制当中。然而,由于其结构的限制,重复控制在变频系统中难以适用,稳定性设计复杂,并且需要大量的存储空间。为解决以上问题,该文提出了一种改进的重复控制方法,在特定频率上采用Fourier分析和信号重构,这样一来使得稳定性设计大大简化。同时,改进的重复控制几乎不需要任何多余的存储空间,并且不需调整就可以用在变频系统当中。为了验证提出的方法,将改进的重复控制用在了逆变器驱动的永磁同步电机控制系统中,来对电流谐波进行抑制。由逆变器死区、永磁同步电机反电势非正弦引起的电流谐波得到了有效抑制。在实验室搭建的1.25 kW的永磁同步电机实验平台上进行了实验,6、12次谐波幅值下降了70%。

Repetitive control （RC） has been widely used for current harmonics suppression. However, RC is hard to use in variable frequency systems due to structural constraints with complex stability designs and large memory space. This paper presents an improved RC method using Fourier analyses and signal reconstruction at selected frequencies, which simplifies the stability design. The method requires almost no extra memory space and can be used in variable frequency systems without adjustment. The RC method is used to suppress current harmonics in a permanent magnet synchronous motor （PMSM） control system fed by an inverter. The current harmonics caused by the dead-time effects of the inverter and the non-sinusoidal shape of the back electromotive force of the PMSM are effectively suppressed. Tests on a 1.25 kW PMSM platform in the laboratory show that the amplitudes of the 6th and 12th current harmonics are decreased by 70%.