Sensorless Control of PMSM Based on Fifth-Order Generalized Integral Flux Observer and Extended State Observer-Based Phase-Locked Loop

Abstract

This article proposes a sensorless control method for the permanent magnet synchronous motors (PMSM) combining the fifth-order generalized integral flux observer (FOGIFO) and the extended state observer-based phase-locked loop (ESO_PLL). First, due to various nonideal factors, including parameter mismatch, sampling errors, and inverter nonlinearity, the rotor flux estimated by traditional flux observers suffers the dc offset and harmonics. To solve these issues, a FOGIFO incorporating a frequency-locked loop (FLL) is proposed, and the FLL ensures that FOGIFO dynamically tracks the frequency of the back electromotive force signal. This guarantees superior integral characteristics at the central frequency point. Meanwhile, the FOGIFO pole distribution is optimized to enhance the harmonic suppression performance. Subsequently, the analysis of the conventional phase-locked loop is carried out in terms of the error transfer function. The ESO_PLL is used for rotor position and speed observation, which significantly improves the dynamic tracking performance. Moreover, since the proposed method is based on a voltage model in stationary coordinate system, it is applicable to both surface and interior PMSM, and simulations and experiments have verified its effectiveness.