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

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.