Control Strategy for Input-Series Output-Paralleled Converter

The input-series output-paralleled (ISOP) converter, which consists of multiple dc-dc modules connected in series at the input and paralleled at the output, are very attractive in the high input voltage and high power applications. The input voltage sharing and output current sharing of the modules of the ISOP converter should be ensured. This paper reveals the relationship between the input voltage sharing and the output current sharing, and indicates that if the input voltages are sharing, the output currents are automatically sharing. A novel input voltage sharing control strategy is proposed in this paper, which is independent of the output voltage regulation, so the input voltage sharing regulator and the output voltage regulator can be designed independently. The small-signal model of the ISOP converter, in which the basic module is full-bridge dc-dc converter, is derived, and based on the proposed control strategy, the ISOP converter is decoupled to several independent single-input and single output systems. A ISOP converter consisting of two full-bridge dc-dc modules is taken as the example to illustrate the design of the regulators. A 3 kW prototype is fabricated and tested in the lab, and the experimental results verified the proposed control strategy