Estimation of Saturation of Permanent-Magnet Synchronous Motors Through   an Energy-Based Model
  We propose a parametric model of the saturated Permanent-Magnet Synchronous Motor (PMSM) together with an estimation method of the magnetic parameters. The model is based on an energy function which simply encompasses the saturation effects. Injection of fast-varying pulsating voltages and measurements of the resulting current ripples then permit to identify the magnetic parameters by linear least squares. Experimental results on a surface-mounted PMSM and an interoir magnet PMSM illustrate the relevance of the approach. 
AlKassem Jebai, Francois Malrait, Philippe Martin, Pierre Rouchon
math.OC cs.SY physics.ins-det