Strong coupling of circuit and field solvers for simulation of rotating electrical machines

Coupled circuit-field solutions provide a powerful tool to simulate the detailed behavior of electrical machines and other magnetic devices operating as part of a larger system. The coupling of both domains can be made inside a single analysis tool, or it may be attempted by combining two separate-domain programs, thus taking advantage of the individual strengths of existing numerical codes. In this paper, a scheme to implement the latter type of coupling is presented, which extends a previously proposed static method to consider movement of the rotor or some other moving part. The system-level simulator is the Alternative Transients Program (ATP), and the magnetic field solver is FLD. The proposed scheme provides a strong coupling between circuit and field variables and therefore is free from the stability problems which often arise in weak coupling schemes. The method is applied to a test rig resembling a switched reluctance motor, and the results are compared with published measurements.