A Novel Decentralized and Forced Common Duty Ratio Method for Input Voltage Sharing of ISOP Converter

The input-series–output-parallel (ISOP) dc/dc converter is suitable for applications that require high input voltage and output current. In such cases, input voltage sharing across each individual module is crucial to guarantee the safety and reliability of the system. This article proposed a novel duty ratio feedforward control scheme to automatically balance the input voltage of different modules in the ISOP conversion system by ensuring that the duty ratio of each module remains consistent. Compared to the traditional common duty ratio strategy, this method does not require interconnections for information exchange, decentralizes the input voltage sharing (IVS) control strategy implementation to each individual module, and achieves a fully modular design. Furthermore, this approach eliminates the need for input voltage and current sampling, simplifying the control system design. The article outlines the principles and characteristics of the proposed method, followed by a stability analysis based on a small-signal model and a discussion on control system design. Finally, experimental results are presented to validate the effectiveness of the proposed control strategy.