The Control System Implementation Of Brushless DC Motor Base On FPGA

Brushless dc motor because of its simple structure, large power density, excellentspeed regulating performance, low noise characteristics such as widely used in highelectric field.However, the structure of brushless motor electronic commutation replacemechanical brush caused a lot of difficulties and challenges for designing thecontroller.First of all, the reversing current fluctuation easy cause the chip workabnormal, control system is not stable; Second, as the control strategy is more and morecomplex, the closed-loop control cycle is long, the control system of real-time is toreduce; Again, the electronic commutation to drive brushless motor inevitably producetorque ripple, make the brushless dc motor is difficult to get stable output torque, thecontrol system control accuracy is lower.These problems seriously obstruct theapplication of brushless dc motor, especially limits it’s in the field of robot control,aerospace and other high precision applications.In order to solve the control problem of the disc brushless dc motor in thehumanoid robot programs, this article is based on FPGA technology, designs andimplements a high performance brushless dc motor control system. This article firstembarks from the brushless motor structure, the key analysis the cause of brushlessmotor torque ripple, and put forward the optimization control strategy; Then, using theSimulink simulation platform, verify the validity of the optimization restrain strategy;Next, based on the FPGA technology to complete the logic design of high-precisionbrushless controller; Finally on the basis of meet robot control, introduce theimplementation of the brushless motor control system.Brushless motor torque ripple can be mainly divided into commutation torqueripple and non-commutation torque ripple. In this paper, according to the differentperiod of torque ripple generation to restrain, respectively. Commutation torque ripple ismainly due to the rate of disconnect phase current reducing not match the conduct phasecurrent increase, through modulation PWM duty ratio, make the rate of disconnectphase current reduce match conduction current increase in commutation process, so asto suppress the commutation torque ripple. The non-commutation torque ripple ismainly caused by the non-conduction phase follow current, by destroying the followcurrent conditions to suppress the torque ripple; Comprehensive two suppress algorithm,inhibition of brushless motor torque ripple in the whole process of operation. Control platform FPGA as the core, control of the brushless motor with hardware logic way, inorder to improve the efficiency and stability of the control system.Through set up simulation system model of the brushless motor in Simulink, theInhibition of commutation torque ripple and non-commutation torque ripple obviously,the inhibit algorithm is verified. At the same time, through the hardware logic to achievecontrol of the brushless motor, greatly enhance the efficiency and stability of controlsystem. The control system research to similar robot system is meaningful.