Optimal Speed Pattern Generating Method for Acceleration Process of EVs

Electric Vehicle (EV) is an effective solution responding to the energy crisis and environment problems, and is usually used for urban traffic where the acceleration and deceleration are very common. This paper proposes a new method called Optimal Speed Pattern Generating Method (OSPG-method) to improve the economy, ride comfort and safety of the EV during acceleration. First, the OSPG-method works out the optimal speed pattern which leads to minimal energy consumption during a specific acceleration process, 20km/h to 80km/h for instance, based on the optimal control theory. The minimal energy consumption indicates the limits of energy-saving potential. Then the OSPG-method gets a serial of speed patterns and the corresponding torque decision arrays for different time limits, which indicates the acceleration intensity the driver desires. Finally the OSPG-method transfers the offline results of torque decision arrays solved by dynamic programming (DP) into accelerator pedal interpreted map, making OSPG-method possible to be applied in engineering practice easily. The OSPG-method has been simulated in an EV model, and the result shows 0.5%-2.5% energy saving compared to a typical conventional method during acceleration process. The bench test experiment is scheduled in early April. In the end, the advantages and defects of OSPG-method are discussed and the roadmap of consummating OSPG-method is proposed.