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.