Sensorless Control of Synchronous Motor Drives: Accurate Torque Estimation and Control under Parameter Errors

Accurate torque control is of interest in traction and other industrial applications, whose realization is challenged by parameters errors and temperature induced variations. This paper proposes a sensorless technique for resilient torque control in salient synchronous machines. The position observer is driven by the adaptive projection vector for position error estimation (APP) scheme. A second projection vector, orthogonal to APP for non interference, serves for flux adaptation. Based on the torque estimation, a model-based optimal current reference generation for maximum torque per ampere (MTPA) condition is designed to realize accurate torque control. The proposed scheme is validated experimentally on an 1.1 kW synchronous reluctance (SyR) machine test-bench.