By experiments it is proved that the infection of temperature change to USM can be compensated by tracking phase difference, which makes motor run on initial setting point.

• 实验证明通过跟踪电机工作时电压电流的相位差，可以补偿电机本身特性和温度变化等对电机运行的影响，使电机运行在初始设定工作状态，提高电机的输出效率。