An equivalent source model for the study of radiated electromagnetic fields in multi-machine electric drive systems

In this paper we develop an equivalent model for electrical machines which is useful for the study of radiated electromagnetic fields in a multi source environment. The proposed models are created from a representative cylinder loops and cubes carrying a set of currents in the cylinder branches as well as voltages at the nodes of the cubes or loops. The amount of current and voltage of the model are obtained based on the current density and electric field displacement of the windings of the actual machines. The geometry of the cube model were calculated based upon a genetic algorithm-based particle swarm minimization process taking into consideration the actual size and the operating conditions of drive system being studied. To investigate the accuracy of model, the electric and magnetic fields propagated from the model at a point far from the drive systems were compared with the actual model. The simulated results show excellent accuracy and practical simulation time compared to full three dimensional finite element model of actual machine. This makes the proposed model ideal for the development of accurate tools for the estimation of radiated electromagnetic field emissions from electric drives and multi conductor environments during their development stage. For verification, the equivalent model is used in multi machine scale and the results of the equivalent model of multi machine case match the result of the actual model case.