Research On Regenerative Braking Energy Recovery Of HEV

Because the HEV has the motor,when the vehicle brakes or speeds down, the motor is in the regenerative braking state, so the motor can both achieve energy recovery and make the vehicle brake. The energy recycled is used to drive vehicles some day. Then it will extend the mileage of vehicles and improve vehicle utilization. Therefore, regenerative braking is a very important research direction of HEV.During the process of energy recovery, the vehicle's kinetic energy can not be completely converted into electrical energy stored in the storage device, energy loss is unavoidable during braking, such as loss of air resistance, rolling resistance loss, loss of electrical machinery, loss of braking control systems and so on. Only about 60% percent of the mechanical energy can be recovered, how to recover this part of the energy reasonably is very critical. Only braking energy by the motor-driven wheel can be transported to energy storage device along the drive shaft, the non-driven wheel is braked by the fricitional braking. Braking torque distribution is involved during braking, including regenerative braking torque and friction braking torque. Under the premise of the braking safety and stability of the vehicles, energy recovery then can be achieved.A kind of fuzzy logic strategy is applied to regenerative braking energy recovery of Hybrid Electric Vehicle (HEV). Under assurance of braking safety and comfort, the electrical braking control system distributes regenerative braking torque and frictional braking torque reasonably during braking, to make use of regenerative braking characteristic of electric motor as much as possible, so that much more kinetic energy can be converted into electrical energy stored in the battery. First, T-S fuzzy controller is created by the FIS Editor of MATLAB and fuzzy logic rules is worked out; Then, fuzzy logic strategy is connected with "Fuzzy Logic Controller" module of Simulink environment; Finally, the model of fuzzy logic strategy is built in Matlab /Simulink environment, and the model is inserted to the ADVISOR software, then experiments of simulation is implemented.Compared strategy of regenerative braking in ADVISOR with strategy based on fuzzy logic, according to the curve of SOC, amount of energy recovery and efficiency of energy recovery, it shows that strategy based on fuzzy logic can get more regenerative energy.