Observability analysis of sensorless synchronous machine drives

Abstract

This paper studies the local observability of synchronous machines using a unified approach. Recently, motion sensorless control of electrical drives has gained high interest. The main challenge for such a technology is the poor performance in some operation conditions. One interesting theory that helps understanding the origin of this problem is the observability analysis of nonlinear systems. In this paper, the observability of the wound-rotor synchronous machine is studied. The results are extended to other synchronous machines, adopting a unified analysis. Furthermore, a high-frequency injection-based technique is proposed to enhance the sensorless operation of the wound-rotor synchronous machine at standstill

Self-sensing control of the externally-excited synchronous machine for electric vehicle traction application

“…The schematic representation of the EESM is shown on Fig. 1: a three-phase stator, with an externally DC-excited winding in the rotor [6].…”

“…This paper is aimed at presenting a primary study of the feasibility of self-sensing control for EESM traction drives. Three broad approaches for position estimation are tested and compared: 1) back-electromotive force (EMF) integration approach [8], presented in Section III, 2) state-observer approach [6], in Section IV, and 3) high-frequency (HF) injection approach [9], in Section V. The performance of the first approach are presented for medium and high speed. The limitations of the second approach are analyzed.…”

Wound Synchronous Machine Sensorless Control Based on Signal Injection into the Rotor Winding

“…The back-EMF-based methods are reliable and superior in the medium-and high-speed regions [4][5][6][7][8][9][10]. However, they exhibit poor performance in the low-speed region owing to lack of the "observability" [11].…”

Permanent magnet synchronous drives observability analysis for motion-sensorless control

“…Another sensorless technique is the high frequency injection (HFI) based technique [17] [4] [34]. Some authors propose to combine Observer-based and HFI techniques [1] [48] [31].…”

“…In [31], a unified approach is adopted for synchronous machines observability study; the PMSM is treated as a special case of the generalized synchronous machine without further analysis.…”