Analysis and Control Design of a Step-Up/Step-Down Converter for Battery-Discharge Voltage Regulation

In recent years, step-up/step-down DC–DC converters have been required in renewable energy processing and energy storage applications. In the latter, lithium-ion batteries have played an important role since they have been the most usable source in portable equipment and electric vehicles. This paper proposes a novel step-up/step-down converter with continuous input current and a model-based control scheme. Moreover, the converter design highlights based on steady-state analysis are obtained for a proper parameter selection of the converter. Thus, a fourth-order average system model is obtained to design a multiloop control law. The proposed control is designed in such a way that the control scheme results in an inner current loop on the input current and an outer control loop on the output voltage. Finally, experimental results are performed to assess the performance of the proposed power converter and the control law. An experimental setup with an efficiency of 95 % is implemented to validate the theoretical analysis. The intended application is to regulate a voltage fluctuation from 200 V to 250 V to a constant voltage of 200 V with a nominal power of 533 W.