Design and Control of Bidirectional DC- DC Converter for Active Power Decoupling

Single-phase power AC-DC conversion systems face an inherent problem of double-frequency current ripple on the DC port of the system. The simplest solution to this problem is to connect a filter capacitance across the DC port of the converter. But, it leads to low power density and reduces reliability. These limitations can be overcome by replacing the bulky capacitance with an Active Power Decoupler (APD). The present work focuses on the design and control of a bidirectional DC-DC converter-type APD (BDC-APD). A systematic procedure to design the various circuit elements in the APD and the high frequency capacitor across the DC-bus is proposed. Generation of double frequency current reference using second-order generalized integrator (SOGI) is presented and two controller structures for BDC-APD are compared. Results from the numerical simulation are presented to support the proposed design methods and to validate the controller performance.