Harmonic field calculation by the combination of finite element analysis and harmonic balance method

A new finite element analysis for the time- periodic magnetic field calculation is described. An AC magnetic field calculation involving saturation characteristics requires many iterations and much memory region. The combination of FEM and harmonic balance method enables us to economically calculate harmonic magnetic flux distributions at an AC magnetization. The method does not need the calculation concerned with time and the the calculation algorithm is the same on the nonlinear DC field FEM. The method is applied to the magnetic field analysis of a reactor and an electromagnet

Calculation of nonlinear eddy-current problems by the harmonic balance finite element method

The harmonic balance finite element method proposed by us solves the nonlinear time-periodic solution expressed as the sum of fundamental and harmonic components. This paper describes a new procedure for calculation which emphasizes the field computation in the harmonic domain. As a result, the improvement of reducing memory and calculation time is achieved

Time-periodic magnetic field analysis with saturation and hysteresis characteristics by harmonic balance finite element method

In this paper we shall further discuss the harmonic balance finite element method (HBFEM) for the time-periodic magnetic field with saturation and hysteresis characteristics and its applications. The HBFEM enables us to calculate the distribution of harmonic magnetic flux at an AC magnetization, and it dose not need the intricate calculation concerned with the time variation. Comparisons between numerical analysis and experimental results are presented

Harmonic balance finite element method taking account of external circuit and motion

The alternating-current electric machines are usually excited by voltage sources and the external elements are connected in the magnetizing circuit. Therefore the magnetic fields including nonlinear characteristics, voltage sources and external circuits should be considered together in the analysis model. Furthermore, the motion effects in field problem of electric machines must be sometimes taken into account. This paper describes a new approach for analyzing the time-periodic nonlinear magnetic field problems considered external circuits and motion in the harmonic domain by using the harmonic balance finite element method. The system equation for governing magnetic field with motion and circuits is investigated. A few applications are discussed

Numerical analysis of a new magnetic frequency tripler with series-connected reactors

The authors propose a new magnetic frequency tri­pler with series-connected reactors, and present a numerical analysis of the tripler. In the analysis, Φ-i characteristic of saturable reactor is approximated by (if th-order plynominal, and nonlinear ordinary d if­ferencial equations for flux linkage are derived from an equ ivalenc circuit. The nonlinear simultaneous equations, which are obtained by using the method of Harmonic Balance, are solved by an improved Newton\u27s method. The improved numerical method enables to de­termine optimum gap length and coil turns of the re­actors. Experimental results, which are obtained by using the reactors with the numerically determined gap length and coil turns, show a constant voltage charac­teristic up to a certain load and a drooping character­istic above that load

Four components three dimensional FEM analysis of flux concentration apparatus with four plate

This paper deals with the four component three dimensional FEM analysis of a flux concentration model with four thick conducting plates placed between a pair of a.c.-excited coils. We have already analyzed a flux concentration apparatus with two conducting plates by using a newly developed iterative 3-D calculation method.[1] [2] An improved formulation is also treated in this paper. This calculation method is applied to the present four-plate type model, to prove its adaptability and to search for more efficient design of such apparatus. Distributions of flux densities, eddy currents and scalar potentials are calculated and discussed. The role of the scalar potential for the 3-D eddy current diffusion problems is also interpreted, based on our calculation results

Harmonic balance finite element method to applied nonlinear ac magnetic analysis

The harmonic balance finite element method(HBFEM) we proposed is suited to analyzing the time-periodic magnetic field. An AC magnetic field calculation involving saturation characteristics requires many iterations and the intricate procedures for the time derivative. The procedure of the numerical calculation for a new FEM is intrinsically similar to that for the static nonlinear magnetic problem. The paper describes the formulation for the time-periodic magnetic field problems with any saturation characteristics. The calculations applied to a reactor and an electromagnet verifies the formulation of the HBFEM

Three dimensional flow of eddy currents in flux concentration apparatus

This paper deals with three dimensional analysis of the eddy current distribution in a cylinder-type flux concentration apparatus by using a four component finite element calculation method. In order to solve z-ward component of eddy currents in a new model with multi-rims, boundary conditions of four components are discussed. We have already examined and analyzed several types of flux concentration apparatus, which utilize the flux concentration effect of eddy currents [1][2][3][4]. However, in these models treated in the references shown above, we do not have to consider the current component perpendicular to the excitation current. In order to obtain three dimensional flow of eddy currents, boundary conditions for four variables should-be selected carefully. Boundary conditions especially for z-ward vector potential and the scalar potential are discussed

Improvement of characteristics and applications of the magnetic frequency tripler with bridge-connected reactor circuit

This paper presents improvements and applications of magnetic frequency tripler which is composed of the bridge-connected reactor circuit reported in the previous papers. [1,2] Generally speaking, a frequency multiplier composed of nonlinear magnetic elements indicates the very difficult conversion operations as this tripler does. In such kind of problems, the numerical analysis of nonlinear equations will not be clarified the physical relations among several parameters. Sometimes it is difficult to solve the relations needed in the design. Therefore, the experimental analysis of each parameter was done in this paper. As the result, quantitative relations between characteristics and circuit constants may be derived. It is possible to clarify the optimum circuit conditions. The new circuit composition with improved characteristics is obtained. Moreover, this paper indicates, as an example of applications, the nine times frequency multiplier composed of two bridge circuits connected in cascade

Finite Element Analysis of Nonlinear Magnetic Devices Combined with Circuit Equations by Tableau Approach

When simulating electric machines, the magnetic field analysis and the circuit calculation are coupled closely. We present a method in which the combination of Maxwell\u27s equations and circuit equations is solved simultaneously. The tableau approach as nodal formulation is applied to the circuit model. This paper describes a new generalized approach for considering the external networks in the harmonic balance finite element method we proposed. The approach is applied to the analysis of a magnetic frequency tripler with circuit elements