船舶轴带无刷双馈电机短路电流分析与保护设计

Short-Circuit Current Analysis and Protection Design of Ship Shaft Brushless Doubly-Fed Generator

当船舶轴带无刷双馈电机(BDFG)功率绕组发生三相短路故障时,短路电流会对系统造成较大的危害。因此,有必要设计专门的保护电路保障系统的安全。利用空间旋转坐标系,建立船舶轴带BDFG功率绕组三相短路时的动态方程,并依据磁链守恒定律研究系统短路电流的变化特性。通过分析短路电流的各个分量,提出加入撬棒电阻和直流卸载电路的保护方式来卸载过电流,并进一步研究加入保护电路后的电流变化特性。以1台30kVA的BDFG为仿真对象,运用MATLAB/Simulink进行模型仿真和理论值计算,验证了保护电路的有效性,对船舶轴带BDFG电气安全设计具有指导意义。

When a three-phase short-circuit fault occured on the ship shaft with a brushless doubly-fed generator(BDFG),the short-circuit current would cause a great hazard to the system.Therefore,it was necessary to design a special protection circuit to ensure the safety of the system.Based on the space rotating coordinate system,the dynamic equation of the three-phase short circuit on the power winding of the ship shaft with BDFG was established,and the variation characteristics of the system short-circuit current were studied according to the law of magnetic flux conservation by analyzing the components of the short-circuit current.It was proposed to add the crowbar resistor and the DC unloading circuit to unload the overcurrent,and the current variation characteristics were further studied after adding the protection circuit.A 30 kVA BDFG was used as the simulation object.Model simulation and theoretical value calculation were carried out by MATLAB/Simulink.The effectiveness of the protection circuit was verified.It was instructive for the electrical safety design of the ship shaft with BDFG.