摘要
具有非理想梯形波反电势的永磁无刷直流电机在直接转矩控制时必须实时计算反电势值以便估算转矩,计算可以由状态观测器完成。该电机采用六拍换相控制方式,在换相时观测器计算的反电势值与实际值差别较大,导致转矩估算不准。将四种状态观测器通过适当设计用于反电势计算并进行比较,指出反电势计算出现误差是因为观测器的反馈输入中只有电流观测误差的比例项。提出用比例积分观测器来消除这种误差,并利用通用结构观测器对比例积分观测器加以改进,使其适用于电机参数测量不准确的场合。以实际电机系统为观测对象,应用MATLAB编制相应的观测算法,计算结果表明,对反电势计算误差形成机理的分析正确,比例积分观测器及其改进型可以有效消除这种误差。
In a permanent magnet brushless DC motor （PM BLDCM） direct torque control （DTC） system the non-idealtrapezoid back electromotive force （BEMF） need be calculated on line to estimate the torque, which can be performed by astate observer. Because of the six-beat commutation control mode of this motor there is error in calculated BEMF at commu-tation points which leads to inaccurate torque estimate. Four state observers were designed for BEMF calculation and com-pared. Through comparison the error in calculated BEMF was thought to be caused by the observers爷feedback input whichonly contained proportional component of the current observation error. A proportional-integral observer （PIO） was recom-mended to eliminate the error, and a general structured observer was used to improve on the PIO for motor parameters un-certainty. Using a real motor as the observed object, foregoing observers were realized by MATLAB. Calculation resultsshow that the cause of the BEMF calculation error is analyzed correctly and the PIO and its improved version can eliminatethis error.
出处
《微特电机》
北大核心
2014年第11期6-9,共4页
Small & Special Electrical Machines
