Compensation of Saliency Tracking Static Estimation Errors in Sensor Fault Tolerant IPMSM Drives

Rotor position transducerless control (self-sensing) techniques emerge as promising software-based sensor replacement strategy for redundancy concepts in industrial applications. Interior permanent magnet synchronous machine (IPMSM) drives offer the required physical properties for effective online motion state estimation. At low speed range including standstill, high frequency signal injection (HFSI)-based saliency-tracking methods estimate the rotor position solely utilizing terminal machine properties. However, implementation of HFSI is challenging and highly reliant on the given machine design. Load dependent non-linear phenomena can have detrimental effects on estimation accuracy and hence the required robustness, limiting the use in fail-operational safety-relevant applications. This paper proposes a modified implementation strategy for using HFSI as part of a position sensor redundancy concept for highly utilized IPMSM drives. A simple identification procedure is presented, isolating static position estimation errors. Experimental results confirm effective compensation of satuartion-induced errors, maximizing the fault-detection and fault-compensation capabilities of the proposed strategy even under heavy load conditions.