Control Strategy of Mitigating the Low-Frequency Ripple Current of Single-Phase Rectifier

There is the second harmonic current at the output DC side of the single-phase rectifier for the instantaneous input power pulsation at twice the AC frequency. This second harmonic current will be detrimental to its output utilities without a large capacitor at the DC-link. In this paper, the advantages and disadvantages were analyzed through the comparisons of two waveform control algorithms of voltage control mode and current control mode and an optimized waveform control method of voltage control mode is proposed. Unity power factor can be realized at the AC side and the low-frequency current ripple can be restrained at the DC side with the proposed control method. Meanwhile, the proposed control algorithm takes a low circulation energy inside the rectifier without any other undesired harmonics. The effectiveness of the proposed control algorithm was verified from theoretical analysis and simulation results. This algorithm would be appropriate to the power conversion applications without electrolytic capacitor system.