Design And Implementation Of The BLDC Controller In Electric Vehicles

As the global energy crisis and environmental pollution more and more serious in the world, new energy vehicle has been paid more and more attention. By comparison, the Blade electric vehicles (BEV) gains power from electric energy which realize "zero emission" of vehicle exhaust in real sense. Therefore, BEV is regarded as an effective way to solve the energy shortage and environmental pollution.For the BEV, the motor rotates to drive the car. It directly affects the performance of the BVE. Without brush wear, brushless DC motor (BLDC) services longer than others. For the BLDC to develop a controller in the electric vehicles, there will be a very broad market prospects. Based on the analyses of the development tendency and market demand of BEV, the present paper carries out research and design work on the core part of BEV—driving controller so as to realize the control of BLDC. The main work is as follows:Firstly, the present paper introduces the principles and control methods of brushless DC motor, and thus determines the overall design of the controller. In the present paper, speed and current double-closed-loop control methods are taken to realize the control of brushless DC motor. In order to effectively recover braking energy and extend operating range, the method of regenerating braking is applied. The controller is divided into two main segments:control segment and power driving segment.In the hardware design, the motor control chip—DSPIC30F2010manufactured by Microchip is selected as the main control chip. The power module circuit, power driving circuit, detection circuit, protection circuit and other circuits are designed. The power driving segment adopts the method of MOSFET parallel. In order to improve heat dissipation, aluminum substrate is selected.In the software design, according to the requirements of BEV’s driving need and characteristics of the brushless DC motor, the control program is divided into the following programs:system initialization program, PWM signal output program, protection module, double-closed-loop speed regulation module, regenerative braking module and operation parameter detection module. In addition, as for the potential interferences that may be confronted by PEV in motion, anti-interference measures are likewise taken in the software design.Finally, through the debugging of the hardware and software, we modify the problems existing in the design. And then the brushless DC motor is tested on the constructed test-bed. After that, the author makes some partial testing by installing the controller on the BEV’s frame. It’s learned through the tests that the controller has achieved the anticipated goals.