Digital Signal Processing Reference
In-Depth Information
electromagnetic field distribution and the influence of the thermal convection on the
core temperature field, a physical model adding air convection must be established,
moreover, the air district must completely cover the part of the whole winding, and
adjacent to the core. The flux density of the air is 1 Gs, the air convection coefficient
is 12.5 W/(m
2
·K).
Fig. 2.
The schematic structure of the transformer cross-section
3.2
Division of the Grid
The finite element mesh plays a vital role in the numerical simulation process, which
directly affects the subsequent numerical calculation accuracy and precision of the
analysis results. The number of grid number will also affect the efficiency and the size
of the computational calculations. In general, calculation accuracy will be increased
with the number of grid, but the calculate amount will also increase at the same time,
thus, the two factors should be taken into account when determine the number of
cells. To ensure the difference of the cell size is not large, and to obtain a satisfied
simulation result in large temperature gradient, we divided the entire model into
uniform grid automatically, thus the simulation process can be conducted normally.
3.3
Voltage Loads Imposed and Results of Solving
The applied load is voltage drop in the magnetic field analysis. A DO loop program
was used to cycle back and forth between the harmonic electromagnetic and transient
thermal analysis. The voltage value at different time is written to a number of load
steps, then the SOLVE command was used to perform each load step. The magnetic
