摘要：针对磁悬浮控制力矩陀螺无刷直流电机电阻、电感值极小的特点和已有的无位置传感器I/f起动算法加速阶段换相精度不高且算法复杂的问题，通过分析电磁转矩和换相时刻的关系，提出了一种改进的I/f起动方法。该方法在电磁转矩恒定的情况下，结合电机模型，精确计算出电机换相的具体时刻。为保证电磁转矩恒定，确保换相时刻的准确性，采用神经网络法估计反电势系数，并设计了基于三相绕组不对称补偿的改进的电流环。仿真和实验结果表明：所提I/f起动方法换相精度较高，能实现电机可靠快速起动。

关键词：磁悬浮控制力矩陀螺；无位置传感器；转矩恒定；改进的I/f起动方法
Abstract: Aiming at the characteristics of Magnetically Suspended Control Moment Gyro (MSCMG) motor and the starting problem of sensorless brushless DC motor (BLDCM),an improved I/f starting method was designed avoiding the problems of traditional I/f methods according to the direct relation between the electromagnetic torque and the commutating instant. In this method, the amplitude of electromagnetic torque was kept constant by estimating the torque coefficient through neural networks and by using an improved current loop, where compensation of resistant asymmetry was proposed. Simulation and experiment results show that the improved I/f accelerating method can start the motor fast and reliably with comparatively high commutating accuracy.

Key words: magnetically suspended control moment gyro； sensorless control； constant electromagnetic torque；improved I/f starting method