A Strategy to Recycle the Braking Energy of HEV with EMB 2014-01-2542

Recovering the braking energy and reusing it can significantly improve the fuel economy of hybrid electric vehicles (HEVs).The battery ability of recovering electricity limits the improvement of the regenerative braking performance. As one way to solve this problem, the technology of brake-by-wire can be adopted in the HEVs to use the recovery dynamically. The use of high-power electrical equipment, such as electromechanical brake (EMB), is working in the form of brake-by-wire. Due to the nature of EMB, there exists an obvious coupling relationship between the energy flow and brake force distribution. In this paper, a brake force distribution controller is proposed in HEV with EMB, which can maximize braking energy recovery, compared with the conventional distribution control without EMB. Meanwhile, an energy flow strategy working with the distribution controller is designed, which is less limited to the performance of the battery. In this strategy, the recovery transfers to the motor of EMB directly, rather than being stored statically in the battery, so it improves the efficiency of the braking energy recovery. The performance of the strategy was studied using a front-wheel drive HEV with EMB based on 42V car power net system model. The simulation results show significant higher energy recovery rate in comparison to the conventional recycling strategy.