Research On Control Strategy Of Electric Vehicle Brushless Dc Motor And Hardware In Loop Simulation System

With the development of new energy vehicle technology and improvement of people’s living standard,it becomes convenient for people to travel and greatly reduces the environmental pollution since the battery electric vehicle appears.Due to simple structure,easy control,small volume and so on,permanent magnet brushless DC motor is widely used in battery electric vehicles,in addition,motor control system has become the core unit of the vehicle.However,the high torque ripple in low speed has become the major problem to be solved because of the motor body,the control methods and others.At the same time,with automotive electronic control system growing,its complexity is also higher,low flexibility,long cycle and high cost in the process of development have made it unable to keep up with the development of new energy automotive industry for traditional test of the ECU.Firstly,the concept of hardware in loop test and the basic principle of permanent magnet brushless DC motor and focused on the reasons and suppression methods of torque ripple by analyzing the research status of the permanent magnet brushless DC motor are described;Secondly,the direct torque control and the simplified control strategy for brushless DC motor are analyzed,then the simulation model based on the PI control and the simplified direct torque control are built,and two kinds of control strategy after the off-line simulation is compared,which verified that the latter can restrain the torque ripple of the brushless DC motor effectively at low speeds;Thirdly the circuit and related software of brushless DC motor based on the dsPIC series are designed for this control strategy;Finally the signal level HIL test system for the motor controller based on dSPACE platform is built,which is according to the analysis and configuration of its software and hardware.The test and analysis to controller in real time in the host computer system not only verify the feasibility of the control strategy,but reflect the superiority of the test method.