A control strategy for a 550000rpm permanent magnet synchronous motor without current and rotor position sensors

A control strategy without current and rotor-position sensors is proposed to drive the ultra-high-speed permanent magnet synchronous motor (UHSPMSM) fed by current source inverter (CSI), which is beneficial to the simplification of control structure as well as the reduction of system size and cost. In the proposed control strategy, command currents of the CSI are obtained by mathematical calculation with reference currents of the motor stator, leading to the removal of current sensors. In addition, an improved sliding-mode-observer (SMO) is used to calculate rotor position, allowing the rotor position sensor to be eliminated. A prototype and the control system were built and the control strategy simulation by utilizing the actual parameters of the prototype was conducted, which verify the effectiveness of the proposed control strategy under 550000rpm.