Sensorless IPMS motor drive control for electric power steering

Key requirements of electric power steering systems such as cost implementation, minimum algorithm complexity and code length, low torque fluctuation and mechanical vibrations are fully complied by the sensorless control technique proposed in this paper, based on high voltage signal injection and measurement of an additional high frequency stator current component. The proposed rotor position estimation technique is simple and can be implemented in analog environment, minimizing the computation effort and the hardware requirements of the microcontroller. Implementation issues and experimental results obtained on a laboratory prototype equipping an electric power steering system in practical working conditions are presented.