本文提出的同步电动机用无刷励磁机的主要作用是在同步电动机转子从零到接近额定转速范围内通过整流器为同步电动机提供励磁。无刷励磁机和整流器与主机同轴。同时，无刷励磁机结构类似于绕线式感应电机，但其定子三相绕组接由晶闸管组成的固态三相交流调压器。这样通过调整调压器就可以控制转子电流的大小。本文介绍了整个无刷励磁系统的原理。此外，对无刷励磁机的等效电路、功率流程、参数等进行了分析研究，并以42000kW（电动机额定功率）实际电机为例，利用由此开发的无刷励磁机电磁设计软件和有限元软件对其进行了计算，其计算结果与试验结果比较吻合，由此说明本文提出的方法是行之有效的。%The main goal used the special brushless exciter in this paper is provided the field current to the main synchronous motor at speed range from zero to close to rated speed by the rectifier. The brushless exciter and rectifier are mounted on the same shaft as the main alternator. The structure of exciter is similar with wound rotor induction machine, but the stator winding is connected with voltage regulator, so current of the rotor winding can be controlled by the adjustment of the regulator. The whole principle of brushless excitation system is presented in this paper. Moreover, the equivalent circuit, power flow, parameters etc. are studied and analyzed for the brushless exciter in this paper. The results on the developed magnetic design software of brushless exciter are proved by a 42000kW motor. And the calculating results through the developed software and FEM software are coincident with the test results well. It shows the method presented by the paper is validity.
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