外文翻译--变频调速交流牵引电机绝缘电老化机理的研究.doc

Investigation on Insulation Electrical Aging Mechanism of Inverter- Fed AC Traction Motors Inverter - fed traction motors used in motor train unit are regarded as the research object for insulation electric aging mechanism, based on re-search productions of insulation technique of inverter-fed motors . High frequency equivalent circuit model s of cable and stator winding are established to simulate over-voltage of motor terminal sand uneven voltage distribution of windings. A novel high frequency high voltage test system has been developed to carry out life time tests of traction motor windings. Change tendency of dielectric loss , partial discharge and thermally stimulated current (TSC) are used to deduce insulation electric breakage mechanism. High frequency equivalent circuit models of cable and stator winding are established to simulate over voltage of motor terminals and uneven voltage distribution of windings. The simulation results show that the over-voltage is the function of rise time , cable length and reflection ratio on motor terminals. Critical length and critical rise time is corresponding one to one. The over-voltage is up to the maximum value as long as the cable length is reater than the critical length A novel high frequency high voltage test system has been developed in place of inverters to carry out insulation aging test. Pulse square waves are generated by IGBT and are enlarged by high frequency and high voltage transformers in the device. The maximum value of high frequency and high voltage square waves is up to 10 kV. The results of life tests of motor windings indicate that he relationship of insulation lifetime and the amplitude of pulses is the inverse power law model , the relationship of insulation lifetime and the frequency of pulses is exponential model under continuous pulses condition. When the test ambient temperature is below 200℃，the temperature has little influence on insulation lifetime of magnet wire with corona resistant