An Autonomous Voltage Control Strategy for IPOS DC Power System With Power-Ripple-Based Low Bandwidth Communication

Input-parallel output-series (IPOS) power system is widely used in high output voltage and high-power applications. To improve the reliability and redundancy of the IPOS system, it is necessary to adopt a distributed and autonomous control strategy without a centralized controller. This article investigates an autonomous voltage control strategy for IPOS dc power system. The principle and characteristics of the control strategy are studied in detail. In particular, the limitations of the control strategy in power balance performance and output voltage accuracy are analyzed. To overcome the limitations, an autonomous voltage control strategy with power-ripple-based low bandwidth communication (LBC) is proposed. The power ripple on the output power line is used to share voltage compensation information among modules, which realizes voltage regulation accuracy control of the IPOS dc power system. The power-ripple-based communication is analyzed in detail. The stability of the proposed control strategy is also explored. The system has high redundancy and reliability in both control strategy and communication. The experimental prototype based on a three-module IPOS system is built to validate the proposed control and communication strategies.