基于转子永磁体磁场定向的无刷直流电机转矩脉动抑制

Torque Ripple Reduction of Brushless DC Motor Based on Rotor Permanent Magnet Field Orientation

无刷直流电机由于非正弦的主磁场分布和反电动势波形,在方波电流驱动下产生较大转矩脉动。为此提出一种基于转子永磁体磁场定向的转矩脉动抑制方法。首先,通过分析无刷直流电机转子永磁体磁场定向dq同步旋转坐标系下的等效模型,得出该坐标系下d轴电枢反应和电磁转矩各自取决于dq轴电流的结果;其次,给出了以变换前后绕组产生的d轴电枢反应和电磁转矩不变为原则的三相电流和dq轴电流之间变换方法;最后,利用该变换方法,得到所需dq轴电流对应的三相电流,并对该电流进行闭环控制,进而实现无助磁和去磁的瞬时恒定转矩控制。所提方法通过Matlab仿真和DSP实验验证了其可行性和有效性。

Due to the non-sinusoidal waveforms of main magnetic field distribution and back-EMF,there are large torque ripples in brushless DC motor under the driving with square wave current.Therefore,a torque control strategy to reduce torque ripple based on the rotor permanent magnet field orientation is proposed in this paper.Firstly,by analyzing the equivalent model for BLDCM rotor permanent magnet field orientation under d-q synchronous rotating coordinate system,it is shown that the armature reaction of d-axis and electromagnetic torque are determined by the current of d-axis and q-axis,respectively.Secondly,based on the principle that the d-axis armature reaction and the electromagnetic torque are unchanged after conversion,the transformation method between the three-phase current and the d-and q-axis currents is presented.Finally,the three-phase currents from the required d-axis and q-axis currents are obtained.These currents are regulated in closed loop form to realize the instantaneous constant torque control without magnetization and demagnetization.The test results obtained from Matlab simulation and DSP experiment show the feasibility and effectiveness of the proposed method.