永磁无刷直流电机负载磁场及其电磁转矩的计算

该文在考虑齿槽影响的前提下，建立了永磁无刷电机电枢反应磁场的解析计算模型，求出永磁电机相绕组的自感和互感。在对水磁无刷直流电机空载气隙磁场和空载相绕组反电动势求解的基础上，结合永磁无刷直流电机主电路的拓扑结构，构造出电机绕组的场路耦合模型，由此计算出电机相绕组电流变化波形。在考虑齿槽影响情况下，计算出永磁电机在任意时刻的电枢反应磁场和负载气隙磁场，进而计算出永磁无刷直流电机产生的瞬时电磁转矩，以便定量分析永磁无刷电机的电磁转短被动和绕组换相引起的转矩被动，为分析永磁无刷直流电机的工作特性和振动噪声提供了可靠的依据。

ANALYTICAL CALCULATION OF LOADED MAGNETIC FIELD AND ELECTRICAL MAGNETIC TORQUE IN BRUSHLESS DC MOTOR

Considering the effect of slots, this paper presents an analytical calculation model of armature reaction magnetic field in permanent magnet (PM) brushless DC motor. The self-inductance and mutual inductance of the windings are derived. Based on the analysis of the no-load magnetic field distribution, the no-load back EMF waveform, the main circuit topology of a PM motor and a field-circuit coupling model of the windings are performed. Subsequently, waveforms of phase current are pictured. Taking into account slots, the armature reaction magnetic field distribution and the loaded resultant magnetic field distribution at arbitrary time are calculated. The instantaneous electromagnetic torque at arbitrary time is investigated, too. Based on the previous work, the electromagnetic torque ripple and the commutation torque ripple can be analyzed quantitatively. The presented method can function as a powerful tool to analyze performance, vibration and noise of a permanent magnet brushless DC motor.