考虑谐波影响后交流励磁电动机电磁转矩的分析与计算

虽然已有不少文章研究了交流励磁电机的运行性能 ,但是很少有文章在研究其性能时考虑了谐波电流的影响 ,特别是谐波对电机电磁转矩的影响。本文从该类电机的基本电磁关系出发 ,分析研究了基波电磁转矩及谐波转矩的特点 ,提出了基波谐波的等效电路 ,给出了谐波电路中参数的计算方法。导出了基波电磁转矩、稳定谐波电磁转矩及脉动谐波电磁转矩的计算公式。文章最后以一个实际的绕线型异步电机用交 直 交电压型逆变器供给励磁的交流励磁电动机为例 ,计算了主要谐波的稳定和脉动的电磁转矩以及电机总的电磁转矩。计算结果对进一步研究系统的驱动性能及电机与励磁系统的设计是十分有益的。

Analysis and Calcualation of Electromagnetic Torques for AC Excited Motors Incorporating the Effect of Harmonic Currents in the Excitation Source

Although some papers presenting the analyses of the steady state operation performances for AC excited machines have already been reported,there are few papers that analyze the operation performance including electromagnetic torque incorporating harmonic currents in excitation source.In this paper,firstly based on the basic electromagnetic relation of this kind of electric machines the features of fundamental and harmonic electromagnetic torque are studied.Secondly,the fundamental and harmonic equivalent circuits are presented and the calculating methods of parameters in the harmonic equivalent circuit are given.The calculation formulas of the fundamental and steady harmonic and pulse harmonic electromagnetic torques have been derived.Finally,the steady and pulse harmonic electromagnetic torques and total electromagnetic torque for AC excited machine consisting of an induction motor with round rotor and a voltage source inverter have been calculated.The study result in this paper is shown that it is helpful for the designs of electric machines and excitation system as well as the operation performance analysis of drive system.