1989 Fiscal Year Final Research Report Summary
Study on Systematic Numerical Analysis of Three Dimensional Magnetic Fields
| Project/Area Number |
63550215
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
電力工学
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| Research Institution | Nagoya University |
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Principal Investigator |
MORISUE Toshiya Nagoya Univ., School of Eng., Professor, 工学部, 教授 (10157894)
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| Co-Investigator(Kenkyū-buntansha) |
FUKUMI Minoru Tokushima Univ., School of Eng., Assistant, 工学部, 助手 (80199265)
KURIMOTO Hidekazu Nagoya Univ., School of Eng., Assistant, 工学部, 助手 (40144125)
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| Project Period (FY) |
1988 – 1989
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| Keywords | 3D magnetic field / magnetic vector potential / corner(edge) problem / gauge / multiply connected region / boundary integral equation / coupled problem / nonlinear magnetic field |
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| Research Abstract |
(1) The magnetic vector potential is very sensitive to the corner of a high-permeability material. This fact is demonstrated by a 2D magnetostatic field problem that has an exact solution. Then, the cause for this fact is theoretically clarified by using the theory of 2D incompressible and irrotational flow in fluid dynamics, and a method of decreasing the numerical error is developed.
(2) 3D magnetostatic field calculations for gapless magnetic circuits are strongly affected by the discretization. The numerical error is considered to be generated by the imperfect cancelation of the permeability-free terms in the integral equation due to the improper size of the integration region containing a singular point. A method of reducing the numerical error is developed.
(3) The usual method of imposing the gauge on the magnetic vector potential is inconvenient since it is imposed everywhere in space as a constraint. A new method is developed which imbeds the gauge term into the field equation a
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nd makes it appear only at the interfaces between different media and outermost boundary. The method satisfies the Coulomb gauge and yields a unique solution.
(4) A method using the continuous magnetic vector potential and accompanying electric scalar potential is developed for 3D multiply-connected eddy current problems. This method has the advantage that it has no topological problem, while the method using the discontinuous magnetic vector potential accompanying no electric scalar potential is forced to introduce cutting to the multiply connected problem. From the computed results, this method is verified to be correct and effective.
(5) A boundary integral-equation method using the magnetic vector potential is developed for the problems with unbounded free space, which satisfies the Coulomb gauge and yields unique solution.
(6) Coupling between eddy currents and beam deflection is analyzed for a cantilevered beam problem, using the stream function, Biot-Savart's law and eigenfunction-expansion method. Computed results coincide well with experimental results.
(7) A H-method using magnetic field intensity vector as variables is developed for a narrow air gap nonlinear magnetic circuit with a saturable iron core. It is obtained from the comparison of the computed results with the experimental results that the differential permeability should be used, instead of the normal permeability, for time-varying problems. Less
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Research Products
(14 results)
