高占空比斩波串级调速反馈变压器保护优化  

Protection Optimization for Feedback Transformer of Chopper Cascade Speed System at High Duty Ratio

作　　者：林永君[1] 王兴武[1,2] 王兵树 张照彦[2] LIN Yongjun;WANG Xingwu;WANG Bingshu;ZHANG Zhaoyan(Department of Automation,North China Electric Power University,Baoding 071003,Hebei,China;Baoding Sinosimu Technology Co.,Ltd.,Baoding 071051,Hebei,China)

机构地区：[1]华北电力大学自动化系,河北保定071003 [2]保定华仿科技股份有限公司,河北保定071051

出　　处：《电气传动》2020年第1期24-29,共6页Electric Drive

摘　　要：斩波串级调速系统从电机转子侧调节转差功率实现调速,在高占空比运行时转差功率很小,发生逆变故障后逆变直流电流波形呈现稀疏脉冲形状,现有保护策略不能检测到过流故障信号并执行保护动作,极易导致反馈变压器损坏。针对现存问题,分析了斩波串级调速系统的稳态电流特性及逆变故障暂态过程,结合现有保护策略,得出保护失效原因的理论依据,并据此进行保护优化,提出带直流回路欠压保护的优化方案。仿真及样机试验表明,理论分析及推导正确,经优化的保护策略能够在逆变故障时有效保护反馈变压器,可提高系统可靠性。The chopper cascade speed system adjusts slip power from the rotor side of the motor to achieve speed regulation.The slip power is very small at high duty ratio,and the DC current waveform of the inverter shows sparse pulse shape after the inverter fault occurs.Therefore current protection strategies can not detect the fault and perform protective action,which can easily lead to the damage of the feedback transformer.Aiming at the existing problems,the steady-state current characteristics and the transient process of inverter fault of the chopper cascade speed system were analyzed.Combining with the existing protection strategies,the theoretical basis of protection failure was obtained.The protection optimization was carried out and the optimization scheme of under-voltage protection with DC circuit was put forward.The experimental results show that the theoretical analysis is correct and the optimized protection strategy can effectively protect the feedback transformer and improve the reliability of the system when the inverters fail.

关 键 词：斩波串级调速 逆变故障 反馈变压器 保护优化 

分 类 号：TM85[电气工程—高电压与绝缘技术]