Adaptive Observer Design for Wide-Speed Sensorless IPMSM Drives via Equivalent Control Method

This paper presents an adaptive position observer using normalized position error input in wide-speed sensorless interior permanent magnet synchronous motors (IPMSM) drives. The normalized position error observers of saliency-and model-based field orientations method are established, for which the position information can be unified extracted in wide-speed operation. However, this process introduces extra parameter factors and wide-speed operation especially in regeneration mode worsens the dynamic performance of drives. To realize smooth switch between two different drives and fast dynamic response, concept of equivalent control is incorporated into the observer design. The position error dynamic is extended to a third-order model, and the super-twisting algorithm is adopted to estimate high-order total disturbance. The key step is to introduce the corrective terms and the filtered equivalent control term, which forces the error dynamics to approach a finite-time converge second-order differentiator. A rigorous equivalent control stability analysis is set forth, and a convergence analysis of observer states is elaborated. Effective simulation results are included to verify the feasibility of the proposed scheme.