M Mitrofan Curti

An overview of analytical methods for magnetic field computation

In this paper, several of analytical methods for modelling the magnetic field are described. These models are used in design routines of the rotating machines, linear motors as well as actuators. Thanks to their high accuracy and low requirements for computation power, they are successfully implemented in designing high precision machines. In order to enlarge the applicability of the methods it is a common practise to combine two or more model such as Magnetic Equivalent Circuit (MEC) and Harmonic Method (HM), Schwartz Christoffel (SC) mapping and Tooth Contour Method (TCM), those combinations turns into so called Hybrid Methods which are also intended to increase the computation speed and results precision.

A comparison study of modelling techniques for permanent magnet machines

In this paper, four different modelling techniques for permanent magnet (PM) machines are compared for their accuracy and computational complexity. The considered techniques are primarily based on conformal mapping and harmonic modelling. In conformal mapping, the slotted air gap is mapped into a simpler canonical shape, where the field solution is calculated and then mapped back to the original domain. In harmonic modelling, the regions of the machine cross section are represented as Fourier series and coupled with each other by means of boundary conditions. The field solution is obtained by solving the boundary value problem. In order to quantify the accuracy of the field solutions, global parameters such as cogging torque and flux linkage are computed. The effectiveness of the modelling techniques are evaluated by comparing the global parameters and the simulation time with finite element analysis (FEA) results.

Spectral element model for 2-D electrostatic fields in a linear synchronous motor

This paper presents a fast and accurate 2-D spectral element model for analyzing electric field distributions in linear synchronous motors. The electric field distribution is derived using the electric scalar potential for static cases. The spatial potential and electric field distributions obtained by the spectral element method are validated by finite element analysis. Protrusions, voids and rounded edges in the motor geometry are taken into account without loss of accuracy. Furthermore, the convergence and computational load of the spectral element model is investigated.

Separation of volume and surface forces and torques in a DC excited Flux Switching Machine

In this paper the separation of volume and surface forces and torques of a highly saturated DC excited Flux Switching Machine (DCFSM) is presented. The volumetric and surface forces are derived from the stress tensor caused by the magnetic field. High saturation of the iron will contribute in the increase of the internal forces, as a consequence, the resultant torque is also separated in volume and surface torque. The simulation results show that the torque created by the volume forces is contributing to significant part of the total torque. Therefore, the research of the volume forces consequences is becoming a relevant topic for further research.

Magnetic Modeling of a Linear Synchronous Machine With the Spectral Element Method

The field calculus for electrical machines (EMs) is realized solving subdomain problems. Most often, the latter are solved using either finite element analysis (FEA) or the semi-analytical solution of a Laplace or Poisson equation obtained by separation of variables. The first option can capture complex geometries but becomes slow for high accuracy, whereas the second is fast but limited to simple periodic geometries and linear or infinite permeable materials. This paper presents the 2-D implementation of the spectral element method (SEM) for the modeling of EMs. The polynomial basis functions used to approximate the solution in each domain are reaching exponential convergence similar to the semi-analytical solution. Moreover, each element can be represented by a non-square shape resulting in the possibility to model complex geometries. Following the results in this paper, significantly fewer degrees of freedom are needed for the SEM to achieve the approximation similar to the FEA, and consequently less memory and computational time are required.

2D coupled spectral element model for magnetic-thermal analysis of Linear synchronous Motors

Permanent Magnet Linear Motors (PMLMs) are widely applied in xy-positioning stages such as laser cutters, pick & place systems or vision inspection devices [1].