The Design Of EPS Controller Based On Direct Torque Control

Along with the development of electronic technology,automotive power steering system is developed from hydraulic power steering, electric hydraulic power steering system to the comprehensive development of electric power steering system. As a core component of electric power steering,servo motor, especially the permanent magnet synchronous motor with the excellent performance has also been researched and developed by many experts and scholars, and the direct torque control method, as the most innovative motor control method, has also become a hotspot. In this paper,in the use of direct torque control method to control permanent magnet synchronous motor,an electric power steering system controller was designed, and the control effect of the controller is verified by the experiments.First of all, this article discusses the theory and implementation of direct torque control method. Combined with the idea of space vector pulse width modulation technique, a permanent magnet synchronous motor control system was built, which serves as the base for upper EPS control strategy.Secondly, a steering characteristic curve is proposed. The assistant and return method of EPS system is designed. The simulation of vehicle dynamics model and control model is built by Carsim and the simulation of steering system is built by Simulink. The effectiveness of control strategies is verified by the co-simulation with Carsim and Simulink.Then, TMS320F2812 is chosen as the core chip of EPS controller. Power supply circuit, clock circuit, JTAG debug interface circuit and external interface circuit, voltage and current acquisition and processing circuit, inverter and the driving circuit, CAN communication circuit are designer based on the core chip.Finally, in order to verify the validity of EPS controller, bench experiments of the permanent magnet synchronous motor and direct torque control is designed. So as to the bench experiment of electric power steering system. Results show that the direct torque control method can effectively control permanent magnet synchronous motor, and EPS controller designed increases the steering and return performance of vehicle.