Bidirectional Converter-Based Second-order Ripple Power Suppression With Partial Power Conversion and Series Voltage Compensation Method

A second-order ripple power suppression circuit based on series voltage compensation and partial power conversion bidirectional dc/dc converter is proposed for single-phase AC-DC power system. The series voltage compensation structure is composed of a passive capacitor and a bidirectional dc/dc converter-based active capacitor. The voltages of both the active and passive capacitors fluctuate in a wide range to suppress the second-order ripple power while reduce the volume and size of the decoupling capacitors. The voltage fluctuation of the passive capacitor is compensated by the active capacitor, so that a low ripple of the total output voltage of the AC-DC converter is achieved. Since only partial of the ripple power is processed by the bidirectional dc/dc converter-based active capacitor, the power rating and loss of the bidirectional converter is reduced. To compensate the power loss of the bidirectional converter, another dc output port is introduced into the power factor correction converter. The operating principles, characteristics, modulation and control of the proposed converter are analyzed in detail. A 1-kW prototype was built and tested. The effectiveness and feasibility of the proposed method are verified with experimental results.