Abstract：Doubly fed induction generator (DFIG) is one of the most widely used forms of wind power generation systems. It has the advantages of small capacity, small volume and low cost. Due to the power supply form, the common mode voltage of the converter induces the bearing currents which cause the bearing premature failure. The brush grounding and insulating bearing are the two often adopted methods in the industry on suppressing bearing currents. However the effect of different bearing insulation methods such as insulating the bearing housing, insulating the end cover, spraying bearings and hybrid bearings should be compared and analyzed theoretically. In this paper, the equivalent circuit for analyzing the bearing currents was set up. The sensitivity analyzing of insulation layer on the suppression method was carried out. Then the influence of the position, thickness and material of the insulation layer were studied. The analysis shows that the hybrid ceramic bearing is the most effective method to suppress the bearing current. The insulated bearing housing or end cover is useful to decrease the bearing voltage while the insulation layer is thick enough, but the brush is still needed to suppress the bearing current. The sprayed insulated bearing cannot effectively suppress the high frequency bearing voltage and current because of the thinner coating.
刘瑞芳, 陈嘉垚, 朱健, 任雪娇. 轴承绝缘对双馈异步发电机高频轴电压和轴电流抑制效果研究[J]. 电工技术学报, 2020, 35(zk1): 212-219.
Liu Ruifang, Chen Jiayao, Zhu Jian, Ren Xuejiao. Analysis of High Frequency Bearing Voltage and Bearing Current Suppression of DoublyFed Induction Generators Based on Bearings Insulation. Transactions of China Electrotechnical Society, 2020, 35(zk1): 212-219.
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2020, Vol. 35 
