What Problems Can You Solve?
The AC/DC Module interfaces handle static, time-dependent, and time-harmonic problems. The time-dependent and time-harmonic formulations use a quasi-static approximation. See Table 1-1 in Overview of the User’s Guide for a list of the preset study types available by physics interface.
One major difference between quasi-static and high-frequency modeling is that the formulations depend on the electrical size of the structure. This dimensionless measure is the ratio between the largest distance between two points in the structure divided by the wavelength of the electromagnetic fields.
The quasi-static physics interfaces in this module are suitable for simulations of structures with an electrical size in the range up to 1/10. The physical assumption of these situations is that the currents and charges generating the electromagnetic fields vary so slowly in time that the electromagnetic fields are practically the same at every instant as if they had been generated by stationary sources.
When the variations in time of the sources of the electromagnetic fields are more rapid, it is necessary to solve the full Maxwell equations for high-frequency electromagnetic waves. They are appropriate for structures of electrical size 1/100 and larger. Thus, an overlapping range exists where both the quasi-static and the full Maxwell formulations can be used.
Physics interfaces for high-frequency electromagnetic waves are available in the RF Module.
Independent of the structure size, the AC/DC Module accommodates any case of nonlinear, inhomogeneous, or anisotropic media. It also handles materials with properties that vary as a function of time as well as frequency-dispersive materials. Examples of applications that successfully simulate with this module include electric motors, generators, permanent magnets, induction heating devices, and dielectric heating. For a more detailed description of some of these applications, refer to the Application Libraries included with the module.