Jjh Johannes Paulides

General Formulation of the Electromagnetic Field Distribution in Machines and Devices Using Fourier Analysis

We present a general mesh-free description of the magnetic field distribution in various electromagnetic machines, actuators, and devices. Our method is based on transfer relations and Fourier theory, which gives the magnetic field solution for a wide class of two-dimensional (2-D) boundary value problems. This technique can be applied to rotary, linear, and tubular permanent-magnet actuators, either with a slotless or slotted armature. In addition to permanent-magnet machines, this technique can be applied to any 2-D geometry with the restriction that the geometry should consist of rectangular regions. The method obtains the electromagnetic field distribution by solving the Laplace and Poisson equations for every region, together with a set of boundary conditions. Here, we compare the method with finite-element analyses for various examples and show its applicability to a wide class of geometries.

Analytical Hybrid Model for Flux Switching Permanent Magnet Machines

With the emergence of energy related issues in the automotive sector, there is a tendency to find new efficient solutions to replace existing electrical machinery. One promising candidate is the flux switching permanent magnet machine (FSPMM). Due to its challenging structure and nonlinear characteristic, in the investigation of the machine, generally finite element method (FEM), and rarely the magnetic equivalent circuit (MEC), are implemented. The following paper introduces an alternative analytical modeling technique by means of a hybrid model, which combines the advantages of the MEC and the Fourier analysis.

Flux-Switching Machine With DC Excitation

This paper proposes a topology of flux-switching machine with dc excitation to improve the field-weakening capability of flux-switching machines. This dc-excited flux-switching machine preserves the structure of typical flux-switching permanent-magnet machines while replacing the permanent magnets with dc field windings. The combined advantages of this type of machine in torque production and field weakening are exhibited and validated by finite element analysis.

Modeling of Flux Switching Permanent Magnet Machines With Fourier Analysis

For applications demanding a high torque density and high speed capability, the flux switching permanent magnet machine is an excellent candidate. However, the double salient structure and nonlinear behavior increases the challenge to model the magnetic field distribution and torque output. To date, only the magnetic equivalent circuit (MEC) is employed to model the magnetic field in an analytical manner. However, the MEC method suffers from a coarse discretization and the need for a relative complex adjustment when rotor movement or a parametric sweep is considered. Therefore this paper discusses an alternative technique based on the harmonic or Fourier model which solves these difficulties.

Design Aspects of an Active Electromagnetic Suspension System for Automotive Applications

This paper is concerned with the design aspects of an active electromagnet suspension system for automotive applications which combines a brushless tubular permanent-magnet actuator with a passive spring. This system provides for additional stability and safety by performing active roll and pitch control during cornering and braking. Furthermore, elimination of the road irregularities is possible, hence, passenger drive comfort is increased. Based upon measurements, static and dynamic specifications of the actuator are derived. The electromagnetic suspension is installed on a quarter-car test setup, and the improved performance using roll control is measured and compared with a commercial passive system. An alternative design using a slotless external-magnet tubular actuator is proposed which fulfills the thermal and volume specifications.

Halbach Permanent Magnet Shape Selection for Slotless Tubular Actuators

This paper describes the effects of changing the magnet shape of permanent magnets (PMs) in a Halbach array applied in a slotless tubular actuator. More specifically, the square shaped magnets are replaced by trapezoidal shaped magnets. A semi-analytical magnetic field solution of regular square shaped magnets is presented and used to approximate the airgap field produced by the trapezoidal shaped PMs. The method is based on dividing the magnets into several radial layers and superposition of the fields to calculate the total magnetic field. The results are compared to finite element analysis (FEA) and show excellent agreement. Using this magnetic field solution, the effect of the shape of the magnets on the magnetic field waveform is analyzed by means of a parametric search.

Analytical and Numerical Techniques for Solving Laplace and Poisson Equations in a Tubular Permanent-Magnet Actuator: Part I. Semi-Analytical Framework

We present analytical and numerical methods for determining the magnetic field distribution in a tubular permanent-magnet actuator (TPMA). In Part I, we present the semianalytical method. This method has the advantage of a relatively short computation time and it gives physical insight. We make an extension for skewed topologies, which offer the benefit of reducing the large force ripples of the TPMA. However, a lot of assumptions and simplifications with respect to the slotted structure have to be made in order to come to a relatively simple semianalytical description. To model the slotting effect and the related cogging force, we apply a Schwarz-Christoffel (SC) mapping for magnetic field and force calculations in Part II of the paper. Validation of the models is done with finite-element analysis.

Electromagnetic and Thermal Design of a Linear Actuator Using Output Polynomial Space Mapping

This paper describes the optimization methodology used in the design of a slotted tubular permanent-magnet actuator for industrial applications. A time-effective optimization procedure is obtained by considering simple analytical design equations in coherence with 2-D finite-element analysis as means to establish the various design variables. The optimization is performed in a multiphysics environment because both electromagnetic and thermal models are created and used in the optimization routine. The original optimization problem is replaced by a surrogate, which is updated or improved iteratively by means of a space-mapping-based technique. Its application for solving coupled magnetic-thermal design problems for electric machines is a rather unexplored topic.

Force Calculations in 3-D Cylindrical Structures Using Fourier Analysis and the Maxwell Stress Tensor

Analytical modeling is still a very effective manner to calculate the magnetic fields in permanent magnet devices. From these magnetic fields, device quantities, e.g., force, emf, or inductance, can be calculated. This paper presents a semianalytical technique, based on a 2-D Fourier series to represent the magnetic field, to describe the force components due to permanent magnets in 3-D cylindrical structures. The Maxwell stress tensor method is selected to calculate these force components in the cylindrical coordinate system. The method is analytically evaluated by inserting the analytical expressions describing the magnetic fields. The obtained force equations avoid the use of numerical integration of the magnetic fields resulting in a fast and accurate force calculation method. An example of a 3-D cylindrical structure is modeled and validated by means of a magnetostatic finite element analysis (FEA), and excellent agreement is found.

Active electromagnetic suspension system for improved vehicle dynamics

This paper offers motivations for an electromagnetic active suspension system that provides both additional stability and maneuverability by performing active roll and pitch control during cornering and braking, as well as eliminating road irregularities, hence increasing both vehicle and passenger safety and drive comfort. Various technologies are compared with the proposed electromagnetic suspension system that uses a tubular permanent-magnet actuator (TPMA) with a passive spring. Based on on-road measurements and results from the literature, several specifications for the design of an electromagnetic suspension system are derived. The measured on-road movement of the passive suspension system is reproduced by electromagnetic actuation on a quarter car setup, proving the dynamic capabilities of an electromagnetic suspension system.