An in-depth study on initial rotor position estimation of interior permanent magnet synchronous motor based on di/dt principle

Two methods for initial rotor position estimation of interior permanent magnet synchronous motor (IPMSM) are developed based on di/dt principle in this paper. Pulse voltage vectors at different electrical angles are applied on the motor, and the di/dt of the motor are calculated to get the information of the rotor position. Fourier analysis is used in method I in order to get rid of the cogging effect. Close-loop controllers are designed in method II, and the final estimation angle will be converged at the rotor position. Experiments on a 40-kW IPMSM are done to show the correctness of the proposed methods.