Output Voltage Response Improvement and Ripple Reduction Control for Input-Parallel Output-Parallel High-Power DC Supply

A three-phase isolated ac-dc-dc power supply is widely used in the industrial field due to its attractive features, such as high-power density, modularity for easy expansion and electrical isolation. In high-power application scenarios, it can be realized by multiple ac-dc-dc modules with input-parallel output-parallel mode. However, it has the problems of slow output voltage response and large ripple in some special applications, such as electrophoresis and electroplating. This article investigates an improved adaptive linear active disturbance rejection control with flexible adjustment capability of the bandwidth parameter value for the high-power dc supply to improve the output voltage response speed. To reduce the dc supply ripple, a control strategy is designed for a single module to adaptively adjust the duty cycle compensation according to the output feedback value. When multiple modules are connected in parallel, a hierarchical delay current sharing control strategy for centralized controllers is proposed to make the peaks and valleys of different modules offset each other. Finally, the proposed method is verified by designing a 42 V/12 000 A high-power dc supply, and the results demonstrate that the proposed method is effective in improving the system output voltage response speed and reducing the voltage ripple, which has significant practical engineering application value.