Dynamic Load Emulation of Regenerative Braking System during Electrified Vehicle Braking States Transition

Considering the influence of the transition process of a combined brake system between regenerative brake and friction brake, a closed-loop speed control method was proposed to emulate the load of regenerative braking system based on motor- dynamometer set. By analyzing the dynamics of regenerative braking system and emulation system, the key for emulating load of regenerative braking system was unveiled. The key point was to deal with the problem of the disturbance of the braking states transition. Therefore a combination controller including a linear quadratic optimal controller and a sliding mode controller was designed, while the former was used to resist the disturbance, and the latter was used to compensate the offset of performance index bringing by the nonlinear part. Simulations were carried out to test the effect of the proposed combination control. The results showed that the designed combination control could resist the disturbance effectively and has better dynamic characteristics than traditional PI control.