Dániel Marcsa

Comparison of the

We present two eddy-current field potential formulations to solve rotating electrical machine problems by applying the finite-element method (FEM) using the motional A *- A-potential formulation and the motional T, Phi-Phi-potential formulation. We use the single-phase and three-phase solid-rotor induction motors of Problem No. 30a of TEAM Workshops to compare the potential formulations. We have solved both problems in the time domain and the frequency domain.

{\mbi A}^{*}{-}{\mbi A}

Abstract A major problem in switched reluctance motor is torque ripple, which causes undesirable acoustic noise and vibration. This work focuses on reducing the undesirable torque ripple in 6/4-pole three-phase switched reluctance motor by geometry modification and using control technique. The proposed method combined the specially skewed rotor pole shape with instantaneous torque control with sinusoidal torque sharing function. The results of geometry modification are analysed through the three-dimensional finite element simulation to determine the appropriate skewing angle. The drive performances of conventional and modified motor are compared through the simulations. The effectiveness of the proposed method is also demonstrated and verified by the simulations.

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Purpose – The purpose of this paper is to present the importance of model accuracy in closed loop control by the help of parallel finite element model of a voltage-fed solenoid with iron core. Design/methodology/approach – The axisymmetric formulation of the domain decomposition-based circuit-coupled finite element method (FEM) is embedded in a closed loop control system. The control parameters for the proportional-integral (PI) controller were estimated using the step response of the analytical, static and dynamic model of the solenoid. The controller measures the error of the output of the model after each time step and controls the applied voltage to reach the steady state as fast as possible. Findings – The results of the closed loop system simulation show why the model accuracy is important in the stage of the controller design. The FEM offers higher accuracy that the analytic model attained with magnetic circuit theory, because the inductance and resistance variation already take into account in the...

{\mbi T}, \Phi{-}\Phi

This research presents a field-circuit coupled parallel finite element model of a switched reluctance motor embedded in a simple closed loop control system. The parallel numerical model is based on the Schur-complement method coupled with an iterative solver. The used control system is the rotor position based control, which is applied to the FEM model. The results and parallel performance of the voltage driven finite element model are compared with the results from the current driven model. Moreover, the results of the start-up of the loaded motor show why the model accuracy is important in the control loop.

Formulations for the 2-D Analysis of Solid-Rotor Induction Machines

This paper presents an axisymmetric formulation of the circuit-coupled finite element method embedded in closed loop control system. The controller checks the current of the coil of the magnetic system after each time step and controls the applied voltage to reach the steady state faster. The results of the voltage driven finite element model are compared with the results from the analytical model. The control parameters for the proportional-integral-derivative controller were estimated using the step response of the system. Furthermore, the results of the closed loop system simulation show why the model accuracy is important in the controller design.

Design and control for torque ripple reduction of a 3-phase switched reluctance motor

Abstract Because of the exponential increase of computational resource requirement for numerical field simulations of more and more complex physical phenomena and more and more complex large problems in science and engineering practice, parallel processing appears to be an essential tool to handle the resulting large-scale numerical problems. One way of parallelization of sequential (singleprocessor) finite element simulations is the use of domain decomposition methods. Domain decomposition methods (DDMs) for parallel solution of linear systems of equations are based on the partitioning of the analyzed domain into sub-domains which are calculated in parallel while doing appropriate data exchange between those sub-domains. In this case, the non-overlapping domain decomposition method is the Lagrange multiplier based Finite Element Tearing and Interconnecting (FETI) method. This paper describes one direct solver and two parallel solution algorithms of FETI method. Finally, comparative numerical tests demonstrate the differences in the parallel running performance of the solvers of FETI method. We use a single-phase transformer and a three-phase induction motor as twodimensional static magnetic field test problems to compare the solvers