Model Predictive Control Of Regenerative Braking For A Medium Hybrid Electric Vehicle

Regenerative braking is a basic function of Hybrid Electric Vehicles (HEVs) and pure Electric Vehicles (EVs), it not only recovers the regenerative energy, but also reduces the temperature rise of brakes, and increases the braking safety and efficiency .So it has great theoretical significance and practical application value on the research of the HEVs regenerative control algorithm.The model predictive control (MPC)algorithm of regenerative braking for a medium HEV is researched based on the navigation system. The mathematical model of regenerative braking system for the medium HEVs is set up, and the front and rear braking force is reasonable assigned according to the ECE braking regulation. The maximum of the regenerative braking energy is regarded as the cost function, The MPC model of regenerative braking for a medium HEVs is set up and taking 60 seconds as predictive horizon to achieve optimizing control, based on the efficiency of generator, battery temperature and efficiency model. In order to increase the calculation efficiency of the model predictive control algorithm, the accessible area of the system state variables are limited, reasonable discrete quantitative values of state variables and decision variables are decided, language C is adapted to achieve the simulation for MPC with MATLAB/SIMULINK.The simulation is carried out with the global optimal control algorithm, the instantaneous optimal control algorithm and model predictive control algorithm at the cruise downhill and braking mode. The simulation results are as follows.During the regenerative braking modes of cruise downhill, the regenerative braking energy recovery efficiency of the three control strategies as above is the same when the road slop is smaller or shorter. The algorithm of MPC can get higher braking energy than the instantaneous algorithm, and a faster calculating speed which is more than 20 times to the global optimal control algorithm, with regenerative braking energy efficiency decreasing slightly.At the regenerative braking deceleration mode in the flat road, simulation results of the above three different control strategies are the same. With the same braking intensity, the greater the initial braking speed, the more regenerative braking energy recover. With the same initial speeds of deceleration, the smaller the braking strength, the more regenerative braking energy recovery. As the calculation efficiency of the instantaneous control strategy is highest, so it can be used to replace the predictive control strategy in the regenerative braking mode on flat road.The simulation results show that the regenerative braking energy recovery efficiency of model predictive braking with shift reminder is higher than that of model predictive braking without shift reminder.