Research On Regenerative Braking Of Permanent Magnet Synchronous Motor Based On Dynamic Programming

The automotive industry is playing an important role for Chinese development. According to the Ministry of Public Security Traffic Management Bureau released data, a total of 260 million vehicles in China by 2014, including 154 million cars, but also on the rise. Automotive industry brought a lot of pressure on the environment. Emissions, noise caused serious harm to our life and environment. Meanwhile, the car consumes more than fifty percent of the world’s oil, and oil resources are becoming increasingly strained. In this grim backdrop, the electric car attracted more and more attention around the world. And compared to conventional car, the main advantage of electric vehicles is that energy can be recovered by regenerative braking technology when braking or decelerating. The advantage achieved energy-saving and low pollution performance. The regenerative braking technology as a key element had been a hot research topic in the study of people. Permanent magnet synchronous motor with its simple structure, high power density, small size, easy maintenance etc attracted people’s attention, and have been widely used in automobile industry. Our country is a big country of rare earth resources. The application of permanent magnet synchronous motor has the advantage. In this paper, the regenerative braking technology of permanent magnet synchronous motor had been explored in depth.In this paper, the strategy of regenerative braking of permanent magnet synchronous motor is studied. In the safety of circumstances, make its recycling braking energy as much as possible. The main contents are as follows:This paper explained the development of electric vehicles and permanent magnet synchronous motor and the main research strategy of regenerative braking energy recovery control. Secondly, on the basis of permanent magnet synchronous motor structure and working principle established the mathematical model of surface mounted permanent magnet synchronous motor. And using the method of directional magnetic field control tracking controlled the torque and rotational speed of motor. And simulation analysis shows that it has better tracking characteristics. It lays a theoretical basis for the research of process of permanent magnet synchronous motor regenerative braking.According to steady-state model under the directional control of surface mounted permanent magnet synchronous motor, the process of the regenerative braking of permanent magnet synchronous motor is analyzed and the input power model of the motor is deduced, combined with the battery equivalent circuit model to analyze the regenerative braking during power loss between the motor and the battery to establish a power consumption model of regenerative braking. With the transient optimization strategy of regenerative braking energy control motor torque during power loss is minimized as the index. In the safety of the battery and motor circumstances, achieve maximize energy recovery indirectly. Modified brake module in ADVISOR software, and establish S function based on instantaneous optimization strategy. The simulation results show that instantaneous optimization strategy is superior to the strategy in ADVISOR.The global optimization strategy based on dynamic programming analyzes the power loss in the process of regenerative braking. In the ECE conditions, Simulation analysis was carried out on the global and instantaneous optimization strategy respectively. The result shows that, when the braking time is shorter, transient optimization strategy is slightly lower than global optimization strategy based on dynamic programming; when braking time is long, the global optimization strategy based on dynamic programming is superior to transient optimization strategy.In view of the large amount of calculation, the dynamic programming algorithm cannot be used for real-time control problem. We propose a model to predict the dynamic programming algorithm based on the framework. Firstly, use braking strength to predict the speed when braking or decelerating for a period of time. Secondly, in braking process of minimum power loss as the goal, use dynamic programming to take rolling optimization control of the motor torque. The simulation results show that the effect of the dynamic programming algorithm based on model prediction framework can be basically consistent with the effect of dynamic programming algorithm, but the calculation time is greatly reduced. Modified brake module in ADVISOR software, and establish S function based on model prediction framework of the dynamic programming algorithm. The simulation results show that dynamic programming is combined with model predictive control strategy is superior to the strategy in ADVISOR. The policy proves the proposed method can make full use of the braking torque of the motor, and largely reduces the computation time of dynamic programming.