【摘要】 高速重载工况下无刷直流电机断开相换相续流时间较长,有时续流的电角度甚至超过30°,导致常规方法无法检测到反电动势过零点信号,造成换相失败。该文提出基于反电动势函数的无刷直流电机无位置传感器控制方法。通过对断开相反电动势和反电动势斜率的分析,构造了一个与电机转速无关的反电动势函数,其阈值直接对应换相信号。因此不需要反电动势过零点信号,在换相续流时间较长的情况下也能控制电机稳定运行,适用于更宽的工况范围。由于没有使用低通滤波器,该方法还避免了滤波所带来的相移问题。实验结果验证了理论的正确性和方法的可行性。更多还原

【Abstract】 The floating phase of brushless DC motor(BLDCM) has longer commutation freewheeling time under high speed and heavy load conditions. Sometimes the freewheeling interval even exceeds 30 electrical degrees, which causes the conventional methods fail to detect the back-(electromotive force) EMF zero-crossing signal, resulting in commutation failure. A novel sensorless control strategy for the brushless DC motor is proposed in this paper. By analyzing the back EMF and back-EMF slope of the floating phase, a back-EMF function independent of the motor speed is constructed, and its threshold directly corresponds to the commutation signal. Therefore, the proposed strategy does not need the back-EMF zero-crossing signal, and can control the stable operation of the motor when the commutation freewheeling time is long. In addition, since no low-pass filter is adopted, the strategy also avoids the phase shift problem caused by filtering. The experimental results verify the effectiveness and feasibility of the proposed strategy.更多还原