矿用变频器LRC滤波器寄生参数影响研究

Research on influence of parasitic parameters of LRC filter for mine-used inverter

  • 摘要: LRC滤波器寄生参数易引起串并联自谐振,影响滤波器对矿用变频器长线传输系统中电动机端尖峰电压和电压变化率的抑制性能,甚至造成器件烧损,但目前缺少该方面的研究成果。建立了变频器长线传输系统数学模型,在分析LRC滤波器元件寄生效应的基础上,采用频域分析方法研究了寄生参数对LRC滤波器滤波性能的影响,得出结论:LRC滤波器中电阻寄生电感对滤波效果的影响最为突出,导致LRC滤波器滤波性能下降、变频器长线传输系统在阶跃响应过程中超调和震荡问题严重,其他寄生参数的影响微弱。对LRC滤波器电阻寄生电感对滤波性能及变频器长线传输系统动态特性的影响进行了仿真和实验研究,结果表明:LRC滤波器采用铝壳功率电阻时,电动机端电压波形出现失真,上升及下降过程中存在明显的震荡;采用厚膜功率无感电阻可消除因电阻寄生电感引起的系统超调、震荡现象,使LRC滤波器达到较理想的滤波效果。

     

    Abstract: Parasitic parameters of LRC filter are easy to cause series-parallel self-resonance, which influences filter performance of restraining peak voltage and voltage change rate at motor side in mine-used inverter long-line transmission system, and even causes element to burn out. There is a lack of research achievements from the above aspect at present. A mathematical model of inverter long-line transmission system was established. Based on the analysis of parasitic effects of LRC filter elements, the influence of parasitic parameters on filtering performance of the LRC filter was researched by use of frequency domain analysis method. It is concluded that parasitic inductance of resistance in LRC filter has the most prominent influence, which causes filtering performance degradation of the LRC filter and serious overshoot and oscillation problems in step response process of the inverter long-line transmission system, while the other parasitic parameters has little influence. Simulation and experiment were taken out to research the influence of the parasitic inductance of resistance in the LRC filter on filtering performance and dynamic characteristics of the system. The results show that when aluminum-shell power resistors are used in LRC filter, there would be distortion of voltage waveforms at motor side as well as obvious oscillation during rising and falling processes, while when thick film power non-inductive resistors are used, overshoot and oscillation caused by parasitic inductance of resistance would be eliminated, so that the LRC filter can achieve a more ideal filtering effect.

     

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