Design, analysis and experimental verification of a modularized output current ripple-free microgrid inverter

A simple modular passive ripple mirror circuit (PRMC) is proposed for eliminating the inherent high frequency current ripple of switching pulse-width modulation (PWM) inverters. The proposed passive circuit is robust in the sense of without containing neither any power semiconductor switch nor any extra control. Only the reflected high frequency ripples are automatically induced and processed for proper cancellation with the original ripples. It turns out that not only the output power quality can be enhanced but also the inductance of the main power circuit can be reduced greatly. As an example, a single-phase PWM inverter is chosen for illustrating the effectiveness of the proposed PRMC. Experimental results show that the proposed PRMC can indeed achieve the desired performance.