A method for circuit connections in time-dependent eddy current problems

Tsukerman, Igor; Konrad, A.; Lavers, J.D.

doi:10.1109/20.123928

Cited by 53 publications

(22 citation statements)

References 12 publications

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“…The dc resistance of the conductor winding is the same as (4). Substituting (10) into (5), the field equation in the solid conductor winding is (12) Substituting (8)-(11) into (7), the circuit branch equation of the solid conductor winding is (13)…”

Section: In the Region Of Solid Conductorsmentioning

confidence: 99%

Modeling of Solid Conductors in Two-Dimensional Transient Finite-Element Analysis and Its Application to Electric Machines

Fu¹,

Zhou²,

Lin³

et al. 2004

IEEE Trans. Magn.

102

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We present an approach for directly coupling transient magnetic fields and electric circuits. The circuit can contain arbitrarily connected solid conductors located in the magnetic field region. A systematic procedure suitable for both nodal method and loop method is used to couple fields and circuits. The structures of the system equations of the two methods are analogous. The formulations allow the equations in stranded windings and solid conductors to be unified and the coefficient matrix of the system equations to be symmetrical. In order to reduce the solution domain, the periodic boundary conditions are still applicable when the solid conductors are involved. Our approach has been applied to the simulation of electric machines. We give four examples: 1) calculation of the input phase current and output torque when a single-phase induction motor with shaded rings is in locked-rotor operation; 2) simulation of the sudden short circuit of a synchronous generator with starting cage; 3) study of the phase current waveform of an induction motor when the rotor bars are broken; and 4) investigation of the parasitic capacitive impact of the surge voltage on a winding due to drive switching and cable ring.

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Section: In the Region Of Solid Conductorsmentioning

confidence: 99%

Modeling of Solid Conductors in Two-Dimensional Transient Finite-Element Analysis and Its Application to Electric Machines

Fu¹,

Zhou²,

Lin³

et al. 2004

IEEE Trans. Magn.

102

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“…The well-known two-dimensional A-V formulation will be used [25]. After discretization, the problem consists of the nodal vector potentials a, the voltages u over the conductors, plus a set of linearly independent currents (typically loop currents) i.…”

Section: Basic Theorymentioning

confidence: 99%

Domain Decomposition Approach for Efficient Time-Domain Finite-Element Computation of Winding Losses in Electrical Machines

et al. 2017

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Finite element analysis of winding losses in electrical machines can be computationally uneconomical. Computationally lighter methods often place restrictions on the winding configuration or have been used for time-harmonic problems only. This paper proposes a domain decomposition type approach for solving this problem. The slots of the machine are modelled by their impulse response functions and coupled together with the rest of the problem. The method places no restrictions on the winding and naturally includes all resistive AC loss components. The method is then evaluated on a 500 kW induction motor. According to the simulations, the method yields precise results 70-100 faster compared to the established finite element approach.Index Terms-Finite element analysis, eddy currents, proximity effects, reduced order systems.

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“…The analytical tool described here uses a combination of finite element and circuit analysis techniques [1] to arrive at an estimate of the transient losses. Finite element tools that utilize relative motion terms (convective diffusion equation) usually have difficulty arriving at solutions, especially when the relative motion increases above a few 100 m/s.…”

Section: Analytical Toolmentioning

confidence: 99%

Assessment of losses in the field coil of the compulsator under dynamic conditions

Pratap

2003

IEEE Trans. Magn.

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Abstract--Air core compensated pulsed alternators are being developed as compact power supplies for tactical electromagnetic gun systems. The field coil of the compensated pulsed alternator is a critical component that establishes the excitation magnetic field. Since the machine is air cored the number of ampere-turns required from the field coil are significant, especially considering that the excitation flux density near the armature is typically in the range of about 3 T to 4 T and that near the field conductors in the range from 7 T to 10 T. The rotating nature of the field coil requires that it be light so that it can be supported under centrifugal loads. This implies that the current density in the field coil conductors is quite large. One way of overcoming the excessive heating associated with the high current density is to charge the field coil fast (in tens of milliseconds). However charging the field coil too fast also results in transient losses due too proximity and skin effects. These must be accounted for in the design and simulation of these machines.During the discharge into the load, transient currents flow in the armature winding. These currents produce magnetic fields that interact with the field coils and produce additional losses. This calculation is complicated by the fact that there is relative motion between the conductors. This paper describes a two dimensional numerical analysis that has been conducted to evaluate the losses in the field coil under these two dynamic conditions. The method integrates circuit analysis with finite element calculations. This approach is essential because the field coil conductors have a connectivity that must be described in the calculations. The motional aspects have been accounted for by choosing a reference frame on the rotor and carrying out the calculations in the d-q frame attached to the field coil.The results of this analysis are presented, along with the means of optimizing the field coil and machine geometry in view of the transient losses.

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A method for circuit connections in time-dependent eddy current problems

Cited by 53 publications

References 12 publications

Modeling of Solid Conductors in Two-Dimensional Transient Finite-Element Analysis and Its Application to Electric Machines

Modeling of Solid Conductors in Two-Dimensional Transient Finite-Element Analysis and Its Application to Electric Machines

Domain Decomposition Approach for Efficient Time-Domain Finite-Element Computation of Winding Losses in Electrical Machines

Assessment of losses in the field coil of the compulsator under dynamic conditions

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