Research On Output Efficiency Optimization Of Brushless DC Motor Control System

With the continuous development and improvement of power electronics technology,magnetic materials, and control theory techniques, brushless DC motors has been more widely used in civilian areas. However, because of the growing scarcity of energy and energy problem, brushless DC motor energy consumption is an issue had to be considered.DC brushless motor has good mechanical properties as DC motor, and high operating efficiency. But at light loads, the efficiency is greatly reduced, and resulted in a waste of energy.Brushless DC motor's control in energy saving aspect can improve its operating efficiency at light loads. For today's energy scarcity will have a greatly significant impact.This paper makes the following research, by modeling from the brushless DC motor control system to optimize motor efficiency and made the following research:First, the brushless DC motor's working principle and mathematical models were introduced based on theoretical knowledge. Established the simulation control system of DC Brushless motor based on speed and current double closed loop PID control and direct torque control. Simulation waveform analysis verify the correctness of both control systems modeling. And compare the simulation results in the same simulation environment, the results show that the DC Brushless motor direct torque control in double close-loop system can reduce the commutation torque ripple significantly. Thus the enhancement of operation efficiency, and provides a good platform for adding motor efficiency optimization control strategy.Secondly, copper loss and iron loss, two of main control loss, are mainly considered in brushless DC motor system. We derive the relationship between iron loss, copper loss and flux during the motor running and build the loss model of brushless DC motor. Efficiency optimization control module and the minimum loss simulation model are completed by adopting a consumption-based model of efficiency optimization control method of BLDCM drive system. Compared with traditional direct torque control, the ways to improve Brushless DC motor running using the feedback flux calculated under different conditions,not only make copper loss and iron loss reduce to a certain extent, improved the efficiency of motor, also improved the dynamic performance of the system.Finally, we build the experimental platform of BLDCM and give the analysis of experimental waveforms. The design of hardware system contain STM32F103 as the core control circuit, driving circuit, and external auxiliary circuits. Under the integrated development environment of uVision4 we achieve a C language-based software programming. Some of the relevant experiments on brushless DC motors is built on the experimental platform. The experimental results verify that the design of the BLDCM hardware system is correct and valid.