Improved Odd-Harmonic Repetitive Control Scheme for Cuk-derived Inverter

Abstract

This paper proposes an improved odd-harmonic repetitive control (IORC) scheme for a uk-derived inverter. The IORC is composed of a modified odd-harmonic repetitive controller (RC) combined with a proportional-integral (PI) controller plus a feedforward controller to achieve a zero steady-state error in the uk-derived inverter. The IORC features larger gains at odd-harmonic frequencies by modification of the conventional odd-harmonic RC. And, it also adopts a linear phase-lead compensator to compensate for the phase lag of the uk-derived inverter. Hence, the IORC can effectively eliminate the odd-harmonic components in the output current of the grid-connected uk-derived inverter. In addition, it requires less memory space and provides faster transient response compared to conventional RC schemes. However, the distinctive structure of the IORC makes it difficult to guarantee the stability of the overall control system. Thus, in this paper, a new stability analysis method for the IORC system are given, and then a practical design guideline is also provided to obtain the optimal control parameters. Experimental results are presented to validate the proposed controller in the 300-W uk-derived inverter prototype.