无刷直流电动机的无速度传感器数字控制系统设计

Digital control system of brushless DC motor without speed sensor

设计了一种无刷直流电动机BLDCM(BrushLess DC Motor)无速度传感器变频调速系统。以数字信号处理器DSP(Digital Signal Processor)为数字控制器、智能功率模块IPM(Intelligent Power Module)为功率逆变器组成硬件系统,采用反电势过零检测法进行电子换向,实现了BLDCM的无速度传感器转速跟踪。介绍了功率驱动主电路,交、直流变换部分采用单相桥式不控整流电路,以提高逆变电路所需的直流电压。通过检测关断相的反电势过零点来获得转子的位置信号,以控制绕组电流的切换,驱动电动机运转。论述了转速与电流反馈信号的检测。使用T法测转速;采用霍尔电流传感器检测直流侧母线电流;系统中转速和电流均由PID控制器进行调节。控制系统软件由主程序和中断程序组成,给出了系统软件的流程图。实验结果表明,系统调速性能良好。

A variable-frequency speed control system of BLDCM（BrushLess DC Motor） without mechanical speed sensor is designed,which takes DSP（Digital Signal Processor） as its controller and IPM （Intelligent Power Module） as its power inverter. The back EMF（Electro Motive Force） detection method is applied in electronic commutation to realize the speed tracking without sensor. The power driving circuit is introduced. The single-phase uncontrolled bridge- type rectifier is adopted to raise the DC voltage needed by the inverter. The rotor position is obtained by the back EMF zero-cross detection of shut-off phase,which is used to control the changeover of winding current for driving the motor. The measurement of rotor speed and phase current feedback is discussed. The T-method is used to measure rotor speed and Hall current sensor to detect DC bus current,both speed and current are regulated by PID controllers. The control system software consists of main program and interrupt program,and their flowcharts are given. Experimental results show its better speed-regulation performance.