A general parallel structure repetitive control scheme for multiphase DC–AC PWM converters

Abstract

This paper presents a general parallel structure repetitive control (PSRC) scheme for multiphase dc-ac pulse-width modulation (PWM) converters to cancel output total harmonic distortion more efficiently. With parallel structure, categorized harmonic frequency internal models are connected in parallel. Each categorized internal model has its own independent control gain and PSRC can optimize the total convergence rate by tuning the control gains independently according to the harmonic distribution. Compared with a multiresonant controller, PSRC has more compact structure and yields much less computation burden. Compared with conventional repetitive control (CRC), PSRC can achieve a much faster dynamic response without any loss of tracking accuracy or any added data memory. Moreover, PSRC is a general parallel structure RC for housing various existing RC, such as CRC, odd-harmonic RC, and dual-mode-structure RC. Experimental results of the PSRC-controlled three-phase dc-ac PWM converters show the validity and advantages of the proposed PSRC scheme.