Motion simulation and analysis during initial rotor position identification for PMSM based on high frequency voltage injection

Two classical high frequency voltage injection methods based on saliency-tracking were introduced for initial rotor position identification in permanent magnet synchronous motors (PMSMs): high frequency rotating voltage (HFRV) injection and high frequency pulsating voltage (HFPV) injection. However, the injected voltage resulted in rotor movement, which was not allowed in some high accuracy applications. This paper studied the torque response during rotor position detection and proposed the rotor standstill boundary conditions for both methods that the maximum torque must be below the static friction. Then a free motion simulation neglecting the rotor friction and another dumped motion simulation considering Stribeck friction were carried out on a salient PMSM for both methods. According to the simulation results, the motion issues, such as the rotor displacement and speed, the rotor position estimated error and steady-state vibration, were contrastively investigated by comparing the HFRV injection method with the HFPV injection method and contrasting the free motion with the dumped motion. Simultaneously, theory analysis had been carried on to interpret these simulation conclusions and the approaches to reduce rotor motion were presented.