Single-phase PWM rectifier with power decoupling ripple-port for double-line-frequency ripple cancellation

This paper proposes a new technique for double-frequency ripple-power decoupling in a single-phase PWM rectifier that does not require an electrolytic capacitor, which improves the reliability of the system for long-life applications such as LED lighting. A ripple-port is added in parallel with the output of the PWM rectifier to filter the double-line-frequency ripple using the minimum capacitance necessary for power buffering. Hence, a very small, highly reliable film capacitor is used, which will improve the reliability dramatically compared to the bulky electrolytic capacitor option, which increased the power density of the system. The proposed topology doubles the MTBF increases the lifetime by one order of magnitude. Moreover, the design and control of the ripple-port is independent from the PWM rectifier circuit, so it can be dropped in as an auxiliary circuit to an existing design.