Application of Ant Colony Algorithm to the Analysis of High Frequency Equivalent Circuit of DC Motor

摘要

The Electromagnetic Compatibility (EMC) of direct current (DC) motor windings is a system model which is able to reflect the functional characters of the system in the whole EMC specified frequency(150KHz～30MHz). For most motor designing process, it always evaluated the inductance of windings in lower or working frequency; however, when analyzing the conducted interference, it is necessary to take some parameters in high frequency into account in building up the EMC model, such as the noticeable distributed capacitance among the windings or between windings and shells. Past research neglected the common-mode current generated by the high frequency interference through motor bearings coupled with shells, since the parasitic capacitance of rotor core comes from armature windings supplied sufficient paths. In EMC modelling for DC motor problem, first test the impedance of windings by experiments, then generate the equivalent circuit with total parameters. At present, it is a difficulty that how to choose the parameters. Most researchers preferred to adopt analytical calculation, however, it could not reflect the essence of the model since it requires many simplification. As a result, this paper adopted ant colony algorithm (ACA) with positive feedback to intelligent search and global optimize parameters of equivalent circuit. Simulation result showed that impedance of equivalent circuit calculated by this algorithm was the same as experimental result in the whole EMC frequency. In order to further confirm the validity of ACA, PSPICE circuit simulation was adopted to simulate the spectrum of common mode Electromagnetic Interference (EMI) of equivalent circuit. The simulation result accorded well with the experiment result received by EMI receiver. So it sufficiently demonstrated correctness of ACA in the analysis of high frequency equivalent circuit.