High-Precision Sensorless Control Method with Fast Dynamic Response for High-Speed PMSM based on Discrete-Time Back-EMF Deadbeat Observer

High speed permanent magnet synchronous motors (HSPMSMs) are evolving rapidly due to their high power density, high efficiency and wide speed range. However, the carrier ratio of switching frequency over HSPMSM operating frequency is relatively low and even less than 10. It causes serious high speed position sensing problems and degrades the performance of traditional sensorless methods used in standard PMSM. To overcome the performance degradation, an accurate discrete-time HSPMSM model is derived and a high-precision sensorless control method based on discrete-time back-electromotive force (EMF) deadbeat observer is proposed. The experimental results using a 380V, 14krpm HSPMSM and 9kHz switching frequency demonstrate that the steady-state angle error is nearly zero and the error under rated-load acceleration and high-speed loading transient dynamics is small. The robustness of the proposed method has been validated in parameter sensitivity tests against stator resistance and inductance variation.