Research And Design Of The Low-Speed Vehicle Drive Control System Based On DSP

Low-speed electric vehicle (LEV) has no pollution and low demands on the storage battery. It is safe and flexible. LEV is the new energy vehicle encouraged by the country and has become the researching focus. It has broad application prospects. This paper introduces the research and design of the low-speed electric vehicle drive system based on DSP.The reaserch of low-speed electric vehicle drive control system must resolve the key issues as follows:choice of the drive motor, reserch and design of the controller and the choice of control strategy and so on. According to the LEV’s requirements for motor and drive system, this paper uses the permanent magnet brushless DC motor as the driving motor of the system after comparing with various of driving motors. It also does deeply analysis and systematic study on the key problem while the permanent magnet brushless DC motor applied to the LEV’s drive control system.In response to the features of the trapezoidal wave magnetic field and the three-phase stator winding, in this paper it designs the control system composed of given integral part, forward at full speed and back half-speed part, constant pressure and current limit part, the drive circuit part. The controller use the DSP chip TMS320LF2407A as the core control chip, including the power supply, three-phase full-bridge inverter circuit and driving circuit, current sensing, voltage detection, temperature detection, CAN communication design and isolation protection of the controller. Software design uses modular structure to achieve double close-loop feedback control (speed loop and current loop). Through double close-loop feedback (speed loop and current loop) all-digital controller, it ensures the brushless DC motor speed-adjustment system stable operate and realizes speed ascend & descend process, self diagnosis and protection of motor.Finally, by testing the software and hardware of the designed system, the controller completes a mass of of bench experiments and long road tests. Actual operation and experimental results show that the performance of the control system is stable and reliable. The controller can realize the control of brushless DC motor, rapidly starting, high acceleration while running. The maximum gradability can rise to 20% and each performance index reaches the design requirements.