Representation of permanent magnet brushless machine by means of orthogonal functions

Abstract

PurposeTo develop a fast and accurate method of calculation of permanent magnet machines.Design/methodology/approachPresently two ways exist of modeling of synchronous machines – the classic one, when the concept of inductances Ld and Lq is used and the numerical, time‐stepping approach. The first cannot account for precisely the saturation effects, while the second one is highly time consuming. Proposed algorithm replaces inductances by the distributions of flux densities, which were used for their definition, obtained from finite element solutions. Mathematically, the analysis is converted from the space of trigonometric functions to the more general space of periodic functions.FindingsThe compact algorithm of analysis has been found, making it possible to extend its application to other types of machines.Research limitations/implicationsValidation of the proposed method was done only by cross‐checking with integral parameters coming from finite element solution.Practical implicationsA potentially useful idea of representation of an electric machine for control purposes.Originality/valueThe paper presents original concept of the new approach for the representation of electric machines. Parts of that methodology were discussed among specialists during two international conferences and received positive views.

Adaptation of the classical dq method of analysis applied in machines with non-sinusoidal distribution of terminal quantities

“…Application of the parameter 'L' in this method enables the analysis of the axial machine with the same post processing algorithm as explained in [7]. Time-stepping technique enables determination of two dimensional one-sided spectrum of flux distribution harmonics Fig.…”

“…The analysis of axial flux machine has been demonstrated in [7]- [9]. A step by step derivation to obtain basis functions from FEA flux distribution has been elaborated.…”

“…Hence the methodology presented in this work operates in a functional space to uniquely describe the magnetic field in the air-gap at any load condition. As a minimum requirement to represent the machine model adequately, flux density distribution functions at three operating conditions (no-load, armature reaction in d and q axes) are required [7].…”