Fig. 1. Above left a simple transformer with circuit diagram representation
above right. The magnetic coupling of the primary and secondary windings
(shown enclosed by dashed line) is determined using field analysis software.
Fig. 2. Transformer model in Oersted. Field solution is constrained by
defining coils and windings connected to external circuit elements.
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CAE software combines field solver and external circuit parameters
Magnetic field solvers often require that the values of currents in all coil regions be known and specified in advance before the solution can begin. This presents little problem with steady state DC simulations, since the correct currents are easily calculated by Ohm’s Law. The situation is more complex for ac simulations, since the steady state currents are a function of coil inductances and these in turn depend on the nature of the field solution. Often users must estimate coil current levels and use these in an initial trial solution. They then modify their initial guess depending on the voltages computed from the resulting field solution, and repeat the procedure until computed voltages match actual source voltages. Integrated Engineering Software provides a simpler approach by incorporating external circuit element constraints directly into the field solvers of their Magneto and Oersted programs. Users first assign regions as coils, which are defined by the number of turns, and coil resistances. Then the predefined coils are assigned to windings, which are defined by source voltages and external impedances. Then the field solver automatically calculates the correct current level in all coil regions. Enquiry details |
