A Predictive Set-Point Modulation Energy Management Strategy for Hybrid Energy Storage Systems

In the hybrid energy storage system of electric vehicles, the main objective is to guarantee that the dc-bus voltage tracks the desired set point quickly and accurately. However, it is typically difficult for existing methods to provide both short settling time and small overshoot, which results in significant dc-bus voltage fluctuations. To address this issue, in this paper, we propose a predictive-set-point-modulation-based energy management control strategy. A lead-compensator-based predictive set-point modulation method is designed and integrated in the voltage control loop to improve the response speed. Theoretical analysis is carried out for the energy management system, and an explicit expression of the control parameters is derived. Moreover, an adaptive cutoff-frequency-based power allocation approach is proposed to guarantee that supercapacitors (SCs) can provide sustainable power supply in the long term. A laboratory testbed is built to verify the effectiveness of the proposed method. Experiment results show that the proposed method provides a lower dc-bus voltage fluctuation, higher SC capacity utilization, and a better protection for batteries, when compared with the conventional method.