Coordinate control strategy for two‐stage wide gain DC/DC converter

Abstract

Summary Two‐stage converters are widely used in many industrial scenarios, especially in the field of new energy. Through the cascade of two single‐stage converters, the two‐stage converter combines their advantages and can achieve high efficiency in a wide input voltage range. However, the two‐stage converter usually needs a large capacitor to balance the instantaneous power difference between the front stage and the rear stage. The ripple current flowing through the capacitor will affect its lifetime and the overall efficiency of the converter. Although there are many ways to reduce the ripple current, they will increase the complexity of the circuit structure. Therefore, a two‐stage coordinated control strategy is proposed in this paper, which not only reduces the ripple current flowing through the capacitor without increasing the circuit complexity but also effectively improves the efficiency and life of the two‐stage converter. According to the proposed control strategy, taking the Boost cascade LLC resonant converter as the model, a prototype with rated power of 1000 W is established in the laboratory. The experimental results verify the feasibility of the strategy.