Self-sensing control capability of synchronous homopolar motor in traction applications

This paper considers the problem of self-sensing control capability for synchronous homopolar machine. The advantages and disadvantages of the homopolar motor for traction application are discussed. The magnetic anisotropy of this machine allows to implement encoderless control systems which operates in the whole speed range. This feature is very important for traction applications to reduce the cost of the drive and increase its reliability by removing position encoder from the system. The experimental results with high-frequency injection for position estimation prove good capability of this motor for self-sensing control. The use of the response in the excitation winding from high-frequency injection is considered. The ability of the rotor position estimation with the help of this extra measurement channel is shown. The experimental results from the motor tests of the fully electric city bus are presented.