Research On Powertrain Parameters Design And Vehicle Control Strategy For Pure Electric Vehicle With Two Motors

Recent years more and more people begin to realize the problems of environment and show their concern for the energy crisis. Pure electric vehicle has the advantage of zero emission, as it only used battery’s energy. As the upgraded of traditional ICE vehicle, pure electric vehicle will develop with bright future. In order to promote the develop of PEV, many governments all over the world have introduced subsidies and incentives. However the PEV’s widely acceptance is limited by the short driving range and the high cost. Therefore it must go through a long period before it becomes the mainstream of the market. A new configuration of pure electric vehicle with two motors is designed to improve the economy and driving range of the pure electric vehicle. To hit the targets, a few jobs have been done mainly in the following aspects.First, the paper analyzes the energy-saving mechanism of the new configuration together with its implementing approach. Then, the paper finds out the merits and drawbacks of three kinds of typical configuration by analyzing their structure and dynamic relationships. After that, a new configuration of pure electric vehicle with two motors has been put forward to, which can use the torque coupling mode and speed coupling mode at the same time.Secondly, the initial powertrain parameters have been design in order to meet the pure electric vehicle’s dynamic performance. At first, the vehicle’s parameters are calculated to meet the dynamic performance. Then based on the mathematical statistics on the driving cycles, the function and matching principles for the two motors are decided. In order to achieve the reasonable motor’s maximum power, the particle swarm optimization algorithm has been adopted.The results show that the optimized parameters have better economy than the initial parameters. Thirdly, in order to verify the energy saving potential of the PEV with two motors, this paper put forward the control strategy for the new configuration. The control strategy is divided into three parts. That is required torque calculated, driving mode recognition and required torque distribution. The driver’s required torque is the basic torque and the compensating torque. A instantaneous optimization mode recognition result is made. And with the result, a rule-based mode recognition strategy is optimized. The required torque is distributed based on the motor’s high efficiency. By the simulation model created in MATLAB/Simulink, a contrast on the economy performance between the traditional electric vehicle and PEV with two motors has been made. The simulation results demonstrate the control strategy is correct and valid. Also the new configuration shows the better economy than the traditional structure.At last, because of the importance of the motor’s efficiency MAP, a new method has been put forward based on the software named OPPeD (Optimizing Parameterizing Programming Electromagnetic Design).This new method applied only to the PMSM, which is the most common electric motor used in PEV. The PMSM’s efficiency MAP can be used as the benchmark during the evaluation of energy saving potential of the new configuration.The new configuration of PEV with two motors can use the small electric motor when the required torque is small, however the traditional PEV can only use the large motor in spite of it has a low efficiency. Before the breakthrough achieved in the battery technology, the new configuration of the PEV with two motors can become another solution for the PEV’s disadvantages. The result provides a theoretical basis for the possibility.