Analysis of start-retardation modes in high-power synchronous electric drives

Abstract

The article analyzes the start-retardation modes of synchronous electric drives of high-power exhausters, which are accompanied by high starting currents, not only under a direct start, but also under control of electric energy flows from a semiconductor converter. A mathematical model of electric drive is proposed and substantiated for the analysis of transition processes of ac electric drives. This model has an electromechanical converter that constitutes the links with distributed parameters. A distinctive feature of the model is refinement of the magnetization characteristic of the magnetic-circuit steel, which was carried out during full-scale measurements of the variables of the synchronous electric drive with direct start of the exhauster. To check the adequacy of the mathematical model, the results of a full-scale test were compared with the simulation results by statistical methods using Student’s criterion. The computational results using the proposed model were compared with the calculations by the classical models with lumped parameters. It has been noted that, in the overload zone (for M > 1.5 MN) the calculated values differ considerably, with this being especially evident at low speeds. The obtained results can be recommended for selection of the parameters of semiconductor converters.