General Analysis of Combinations of High Frequency Injected Auxiliary Coils in Displacement Sensorless Control

For the traditional high frequency (HF) injection methods of bearingless motors, the HF signal is always injected into the armature winding, resulting in large suspension and torque ripples. In order to solve this problem, a general theory of combinations of HF injected auxiliary coils is presented in this paper. This theory aims to eliminate certain harmonics based on the vector superposition the...