Performance analysis of coupled inductor based multiple-input DC/DC converter with PWM plus phase-shift (PPS) control strategy

A multi-input DC/DC converter based on coupled inductor is proposed in this paper. An interleaved bidirectional buck-boost converter and a full bridge converter are integrated together to derive a combined three-port DC/DC converter. The power density is improved and the circuit structure is simplified because the power devices are completely shared in the primary side and the two filter inductors in the bi-directional buck-boost converters and the isolated transformer in the full-bridge topology are integrated and replaced by the coupled inductors. Furthermore, the pulse width modulation (PWM) plus phase-shift (PPS) control strategy is introduced to achieve the decoupled voltage regulation within a certain operating range. The duty cycle of the bi-directional 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. 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.