Analysis and design of repetitive controller for harmonic elimination in PWM voltage source inverter systems

A theoretical study of the analysis and design of the repetitive controller for eliminating harmonics in pulse-width modulation voltage-source inverter systems is presented. A method of analysing the repetitive control (RC) system from the frequency-response viewpoint is introduced. Based on this method, a systematic way of optimising the design of the system is proposed. Specifically, the closed-loop repetitive controller is modified by incorporating with a zero-magnitude-and-phase compensator and a lead-lag compensator, to improve the stability and tracking accuracy of the inverter system. It is shown both theoretically and through experiments that the harmonics in the inverter's output voltage at different load conditions can be effectively eliminated with the inclusion of the repetitive controller. The advantage and validity of applying the RC in inverters are therefore demonstrated.