A Novel Method for Rotational Speed Observation of Magnetically Suspended High Speed Motor Using Quadrature Phase-Locked-Loop

This paper proposes an FPGA-based Quadrature Phase-Locked-Loop (QPLL) to observe the rotational speed of Magnetically Suspended High Speed Motor, so that the speed sensor can be cancelled. The proposed method can realize the accurate frequency estimation even there exists harmonic component or change in amplitude of the input signal. Also, the proposed frequency observation method decouples with the vibration suppression controller, which reduces the difficulty in the controller diagram and the parameter design. The simulation and experiment validates the effectiveness of the method.