Research On The Regenerative Braking Control Mechanism Of Hybrid Electric Vehicle With An Integrated Starter Generator

With the rapid development of the global economy, energies on the planet have been constantly exploiting and using by human. As one of the modern emerging industries, automotive industry has seen fast development at the expense of massive energy consumption and environmental pollution. As the clean energy vehicles, hybrid electrical vehicles have emerged at the right moment. In the technical field of hybrid electrical vehicles, the regenerative braking technology enables the recycle of the braking energy, which is an important technology to achieve energy saving.First, this paper proposes a structure plan of the ISG hybrid electric vehicle braking system, its working process are analyzed in detail, combined with the automobile braking performance evaluation index, the key factors which influence the braking energy recovery are mainly studied, such as the working efficiency of the motor and battery, the design of the control strategy, etc. On this basis, set up mathematical models for the system components.Secondly, according to the efficiency problem of permanent magnet synchronous motor(PMSM) under different rotational speed, design the sliding mode control(SMC) strategy based on the PMSM operate efficiently. Through the analysis of the characteristics of PMSM, find out an efficient operation curve, and then fixed boundary layer sliding mode controller is designed to control the motor operating in the vicinity of the efficient operation curve, so as to improve the power efficiency of the motor.Thirdly, in view of the joint work efficiency of motor and battery in the process of working, design a fuzzy sliding mode control(FSMC) strategy. Combined with the state-of-charge of battery, motor speed influence on the battery charging efficiency, find a joint work efficient operation curve, on this basis, design the sliding mode controller, which is used to make the motor work near the curve, in order to improve the braking energy recovery efficiency; at the same time, in order to weaken the chattering phenomenon of sliding mode variable structure system, design the fuzzy controller, the control strategy of simulation analysis was carried on.Simulation results show that comparing to the SMC strategy, the final SOC of FSMC Strategy is increased by 0.03, which is improved 0.08 by comparing to Advisor Strategy; in terms of the recovery of braking energy, FSMC strategy is higher by 7.07% than SMC strategy, and higher by 16.13% than Advisor strategy. So, FSMC strategies have a more significant effect in terms of recovery of braking energy.