An extended H∞ observer based on the mean value theorem approach applied to open loop FOC of PMSM drive

Abstract

This paper focuses with the synthesis of an extended $H_{\infty}$ observer based on the Mean Value Theorem (MVT) for the state estimation of the permanent magnet synchronous motor (PMSM) under the Open Loop Field Oriented Control (OL-FOC). At first, an extended observer design based on the MVT combined with the sector nonlinearity approach to stabilizing the observer error of PMSM drive and ensured a minimum disturbance attenuation level to the error. The dynamics of the error are exhibited as a convex theory association of known matrices with time-varying parameters after representing the nonlinear system of the PMSM as a Lipschitz form. Using the Lyapunov theory, the stability terms are obtained and expressed in form of Linear Matrix Inequalities (LMIs), the extended observer gain is gotten offline by solving the LMIs. With two line currents are measured, the extended observer estimates all PMSM drive states and moreover the rotor position. At the end, the suggested approach is applied to PMSM machine under OL-FOC through an illustrative simulation to affirm the effectiveness of the concept.