Synthesis of Low-Voltage Minimum Switch-Count DC Bus Second-Harmonic Hybrid Filters

Active power decoupling (APD) is an emerging technique for second-harmonic ripple filtering in single-phase power conversion systems. It reduces the dc bus capacitance requirement while adding extra active components to the converter. Though capacitance reduction is favourable for improving converter power density and reliability, added active components often make the circuit complex apart from increasing the power losses. Therefore, APD with minimum active component count and reduced loss have gained significant research interest. This article discusses the synthesis of minimum switch count APD topologies that use low-power rated devices. Low-power APD circuits help to reduce the filter loss, making their efficiency comparable to that of the passive filters. The topology derivations are elaborated, and the significant attributes of the derived filters are compared with the state-of-the-art active and hybrid filters to comprehend their relative merits and limitations. The operations of the synthesized unique topologies are experimentally validated using laboratory hardware.