Decoupling-Controlled Triport Composited DC/DC Converter for Multiple Energy Interface

Abstract

In this paper, a decoupled controlled triport dc/dc converter is derived by combining two bidirectional single-phase buck–boost converters and one isolated full-bridge converter for multiple input source applications. The power density is improved, and the circuit structure is simplified because the power devices are completely shared in the primary side. Furthermore, the pulsewidth modulation plus phase-shift control strategy is introduced to provide two control freedoms and achieve the decoupled voltage regulation within a certain operating range. The duty cycle of the bidirectional buck–boost converters is adopted to balance the voltage between the two primary input terminals, while their phase angle is applied to regulate the accurate secondary voltage. Furthermore, zero-voltage-switching soft-switching operation is provided for all of the primary power switches due to the inherent phase-shift control scheme. Moreover, the two filter inductors in the bidirectional buck–boost converters and the isolated transformer in the full-bridge topology are integrated and replaced by the winding-cross-coupled inductors to reduce the component numbers and simplify the magnetic structure. Finally, a 1-kW prototype is built to verify all theoretical considerations, and it is shown that the proposed topology is particularly advantageous in the distributed power generation system with multiple energy sources.