Output current ripple-free PWM inverters

In this brief, a simple modular passive ripple mirror circuit (PRMC) is proposed for eliminating the inherent high-frequency current ripple of pulsewidth modulation (PWM) inverters. The proposed passive circuit is robust in the sense of without containing either any power semiconductor switch or 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.