The current simulation method is presented for calculating three dimensional magnetic field of superconducting ac generator. The method represents the influence of the boundaries by a large number of current loops appropriately positioned at a distance behind the boundary surface so that the boundary conditions on the actual surface of the boundaries are satisfied. The calculated results obtained for the model of the superconducting ac generator are proved to be closely consistent with the measured values.

This paper derives the relative air-gap-specific permeance distribution function by Schwarz-Christoffel Transformation, considering the effect of slotting. Neglecting the iron saturation, and employing the analytical algorithm for partial differential equations, efficient and effective analytical calculations of no-load air-gap magnetic field distribution, armature field distribution, and phase electromotive force (EMF), are demonstrated, considering the stator slots. Subsequently, based on the main circuit topology of a brushless dc motor (BLDCM), the field-circuit coupling model is constructed for the motor, and then the phase current waveforms and load air-gap magnetic field distribution at any time are determined. Consequently, the instantaneous electromagnetic torque is computed, which underpins the quantitative analysis of torque ripple and the pulsation induced by commutation. Hence, the present work paves the way to precise prediction of the motor's performance and acoustic noise. It is a powerful tool for the design of surface permanent magnet brushless dc motors.

This paper presents modeling and simulation of the operation of an 11-phase brushless exciter. The analytical method is based on Kron's tensor method, which is developed for dealing efficiently with the time-varying topology of an exciter circuit during a digital computer solution. The inductances, which are variable with rotor position, are calculated by the two-dimensional finite-element method. The detailed information (normal and fault cases) on the performance of the brushless exciter is obtained, which is beneficial to design engineers. The approach is suitable for both normal and fault cases. As a result, agreement of calculated values with test results shows the validity of the method of calculation and theoretical analysis presented.

This paper clarifies the operating principles of a controllable reactor of transformer type (CRT). In nature, a CRT is equivalent to a multi-winding transformer for which the low-voltage windings (control windings) operate at short-circuited states in turn. This kind of reactor possesses such advantages as smooth power regulation, low current harmonic content, and fast response. Taking account of the coupling of the control windings, this paper examined the current harmonic content for the work winding by Fourier series decomposition, and thus derived the current harmonic coefficients. Based on the solution of the branch current equation of a multi-winding transformer, and introduction of the concept of equivalent winding impedance, a polygon-type equivalent circuit is proposed for a multi-winding transformer. Subsequently, formulae for the branch impedances of the equivalent circuit are presented. According to the harmonic content constraints, the number of control steps is determined. Then, by combining the MMF and branch current equations, an expanded equation about the winding currents and current-limiting reactances is obtained. According to the feature that the control windings are short-circuited in turn, the current-limiting reactances are calculated for each control winding step by step. At last, based on the proposed equivalent circuit for a multi-winding transformer, a simulation model for a CRT is fabricated with MATLAB/SIMULINK/PSB. The simulation results confirmed the presented work, which underpins the further analysis and design of a CRT.

本文采用基于张量电网络所建立的数字仿真模型，对11相无刷励磁机进行了仿真分析。此模型适于处理无刷励磁机所组成的时变网络系统。所需电感参数用二维有限元法算得。最后得到11相无刷励磁机的详细仿真结果，并进行了验证。