Robust control for regenerative braking of battery electric vehicle

Regenerative braking is an effective way to extend the driving range of a battery electric vehicle (BEV). First, the electrical circuit and principle are depicted in detail. Then, the mathematical model is derived step by step, based on parameter perturbation. Combining the merits and defects of H2 optimal control and H∞ robust control, a robust H2/H∞ controller is put forward to guarantee both system performance and robust stability. To attenuate parameter perturbation and nonlinear uncertainty, the H∞ norm of the sensitive functions from the parameter perturbation of the electrical circuit to the control input is taken as the evaluating index of robustness, and the H2 norm of the transfer function from the external disturbance to the angular velocity of the motor as the index of linear quadratic Gaussian control. The agreement between the simulated and experimental results on BEV ‘XJTUEV-II’ validated the feasibility and effectiveness of regenerative braking and showed that the proposed scheme was endowed with good control performance. Furthermore, more energy is recovered, and by the proposed method, the driving range is improved 4% more than that by the traditional PI controller.