A Robust Self-Commissioning Technique for Identification of the VSI Nonlinearity Effect in IPMSM Drives

Abstract

This paper presents a novel self-commissioning procedure for the identification of inverter nonlinearity constant comprised of the average voltage drops on switches and diodes in conduction state and switching delays. Simultaneous estimation of phase resistance, d-axis synchronous inductance, and inverter nonlinearity constant is achieved at standstill condition by injecting sinusoidal d-axis current. The advantages of the proposed self-commissioning method are twofold: 1) The co-estimation capability provides insensitivity towards errors in resistance and d-axis inductance. 2) While sinusoidal d-axis current is injected, the q-axis current is actively maintained at 0A. Thus, no torque is generated during the self-commissioning period. The effect of discontinuous distortions due to non-ideal switching as well as current sensor noise is rejected by limiting the estimation period within a feasible estimation window. Thereby, a necessary minimum phase current magnitude is established for achieving accurate estimation. This paper also provides parameter convergence analysis and the existence of unique solutions during proposed self-commissioning process, further justifying the choice of proposed feasible estimation region.