An EEMF-Decoupled Adaptive Bandpass Full-Order Observer for Sensorless IPMSMs

In the sensorless control of high-power interior permanent magnet synchronous motors (IPMSMs), estimation accuracy is often compromised by low-frequency disturbances and high-frequency harmonics. To address this problem, this article proposes an adaptive bandpass discrete-time full-order observer (FOO), which is first constructed in the stationary frame, and the dynamic error of the estimated extended back electromotive force (EEMF), including the cross-coupling term, is analyzed based on a complex-vector formulation. Then, an EEMF-decoupled feedback controller is designed to realize symmetrical bandpass characteristics of both negative- and positive-sequence components, to ensure unity gain and zero phase delay at the operating frequency. The stability and parameter robustness of the proposed observer are analyzed to demonstrate reliable performance across a wide speed range, and a 300-kW experimental platform is used to validate that the proposed observer significantly outperforms the conventional discrete-time observer by effectively eliminating disturbances and harmonics.