Design and Control Principles of Hybrid Braking System for EV, HEV and FCV

Due to the introduction of electrical regenerative braking, the structure, design and control of braking system of an electric vehicle (EV), hybrid electrical vehicle (HEV) and fuel cell vehicle (FCV) is quite different from the pure mechanical braking system of conventional vehicles. Desirable braking performance not only guarantee to quickly stop the vehicle and maintain the traveling direction stable and controllable, but recapture the braking energy as much as possible on various conditions of road. In this paper, the braking energy characteristics on vehicle speed and braking power in typical urban driving cycles have been investigated. The results provide strong supports to the design and control of such hybrid braking system. Two hybrid braking systems have been introduced. One is parallel hybrid braking system, which has a simple structure and control. The other is fully controllable hybrid braking system. Two typical control strategies for this system have been established. One emphasizes optimal braking performance and the other on optimal braking energy recovery.