Robust Voltage Control of Bidirectional DC-DC Converter With Modified Extended State Observer for Hybrid Power Supply System

The bidirectional dc-dc power converter interfaced with the battery for a hybrid fuel cell (FC) system is subject to various disturbances, such as load disturbance and the electrochemical impedance spectroscopy (EIS) measurement disturbance, which would deteriorate the voltage quality of the system. To this end, in this article, a robust voltage control based on a modified extended state observer (ESO) is proposed and then applied to the bidirectional dc-dc interleaved converter. The proposed modified ESO is constructed to enhance its ability in estimating the disturbances (about -30 dB) and then improve the performance of disturbance rejection. The detailed design process of the proposed method is presented, and a comprehensive theoretical analysis is carried out to evaluate the controller's performance. Compared with the existing ESO-based controller, the proposed controller improves the voltage quality significantly. The efficacy and robustness of the proposed method are validated by both the simulation and experimental results.