The AC/DC Module interfaces handle static, time-dependent, and time-harmonic electromagnetics problems. See Table 1-1 in Overview of the User’s Guide for a list of the preset study types available by physics interface.

Most of the time-dependent and time-harmonic formulations use a quasistatic approximation. The approximation assumes 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.

One major difference between quasistatic and high-frequency modeling is that the formulations depend on the electrical size of the structure. This dimensionless measure is the ratio of the largest distance between two points in the structure to the wavelength of the electromagnetic fields. The quasistatic physics interfaces in this module are suitable for simulations of structures with an electrical size in the range up to 1/10.

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.