Speed and Position Estimation for 5-ph PMSM Using SOGI Based on SMO Considering Short-Circuit Fault

This paper proposes the cancellation of  harmonics and get fundamental back EMFs for precise rotor position and speed estimations under short-circuit (SC) fault, this article introduces a new sensor-less fault-tolerant control method for 5-phase PMSM using a sigmoid sliding mode observer (SSMO) with a second-order generalized integrator (SOGI) to replace the low-pass filter (LPF). For tuning SOGI, two different frequency estimators are proposed. First, a closed-loop synchronous reference frame phase-locked loop (SRF-PLL) is fed back to SOGI for frequency adaptation based on two orthogonally estimated filtered-back EMFs. Second, an independent open-loop frequency estimator (OLFE), based on two-estimated adversely distorted back EMFs, is proposed to ensure simple implementation. The speed and rotor position estimations are eventually accomplished from the quadrature PLL. Both SOGI-SRF-PLL and SOGI-OLFE-based SSMO achieve satisfactory estimation performance under SC fault conditions, eliminate chattering issues, have good tracking errors, and have strong robustness against different disturbances.

Keywords: Multi-phase PMSM, single-phase short-circuit fault, sensor-less fault-tolerant control FTC, sliding mode observer SMO, second-order generalized integrator SOGI.