Performance analysis of a contactless combined auxiliary brake for hybrid electric vehicle

Regenerative braking used in hybrid electric vehicle can recover energy while braking, which can improve the driving distance of electric vehicle. As commercial vehicles trend to large tonnage, the power of vehicle retarding is greater than the power of vehicle driving. It is hard to ensure that braking stability of the automotive only relies on regenerative braking, which influences traffic safety. This research combines regenerative brake and eddy current retarder. It can extend retarding time by sharing the brake torque of eddy current retarder using the regenerative brake. Meanwhile the regenerative brake supplies electric power for eddy current retarder and it will improve the energy efficiency of system. This paper aimed at target type vehicle that is 8 ton new energy commercial vehicles, and established the regenerative brake model and eddy current retarder model, and then combined vehicle running conditions for the system simulation. The simulations revealed that combined auxiliary brake has steady performance under each working condition and meet torque demands of auxiliary brake as well as obviously extend retarding time of traditional eddy current retarder. This system achieves the closed loop of energy and is both compact-sized and energy-saving.