考虑电流振铃特性的悬浮电磁铁等效电路模型

电磁悬浮型（electromagnetic suspension，EMS）磁浮列车通过悬浮斩波器调节悬浮电磁铁电流，进而控制悬浮力，使车体稳定悬浮. 悬浮斩波器驱动悬浮电磁铁过程中所产生的电流振铃会增加开关损耗，造成电磁干扰（electromagnetic interference，EMI），甚至影响悬浮控制效果. 研究悬浮电磁铁电流振铃的产生机理，能为其抑制措施的设计予以指导. 为此，提出了一种考虑电流振铃特性的悬浮电磁铁等效电路模型. 首先，用策动点函数法推导了悬浮电磁铁导抗函数的一般形式，并结合悬浮电磁铁电流的单位阶跃响应特性确定了其导抗函数的最简表达式以及对应的等效电路模型；接着，用判别式法和仿真法分析了不同电路参数对电流振铃特性的影响；最后，比较了同一悬浮电磁铁电流振铃的仿真和实验波形. 结果表明:在所给参数条件下，实验所得悬浮电磁铁电流纹波幅值、振铃峰峰值和振铃频率分别比仿真结果小9.7%、20%和11%；此外，仿真的电流振铃衰减时间约为1 μs，与实验结果接近；仿真和实验所得悬浮电磁铁电流振铃的幅值、频率和衰减特性均能较好吻合，证明了所提电路模型的正确性. 

Equivalent Circuit Model of Suspension Electromagnet with Current Ringing Characteristics

Electromagnetic suspension (EMS) type maglev trains adjust currents of suspension electromagnets through maglev choppers and then control the suspension force to keep the car body stable suspension. The suspension electromagnet current ringing generated by the maglev chopper will increase the switching loss, cause electromagnetic interference (EMI), and even affect the suspension control. Studying the suspension electromagnet current ringing’s generation mechanism is helpful to find its suppression measures. An equivalent circuit model of suspension electromagnet is proposed in view of the current ringing characteristics. Firstly, the general form of the suspension electromagnet’s impedance function is derived by the driving-point function method. Then, based on the suspension electromagnet current’s unit-step response characteristics, the simplest expression of the impedance function and the corresponding equivalent circuit model are determined. Next, the influences of different circuit parameters on current ringing characteristics are analyzed by discriminant and simulation methods. Finally, with the same suspension electromagnet, the simulation and experimental waveforms of the current ringing are compared. The results show that for the specified parameters, the current ripple amplitude, ringing peak value, and ringing frequency of the suspension electromagnet obtained from the experiment are 9.7%, 20%, and 11% lower than the simulation results, respectively. In addition, the simulated current ringing attenuation time is about 1 μs, which is close to the experimental results. The simulation and experimental results of the suspension electromagnet current ringing are in good agreement in terms of the amplitude, frequency, and attenuation characteristics, validating the proposed circuit model.