Establishment of intelligent shearer bus electromagnetic interference model and wiring process optimization

Abstract

Intelligent shearer is a key equipment for a fully mechanized coal mine working face. For intelligent shearers, due to the internal space limitation of flameproof electric control box, there are usually mixed wiring situations with the cables of internal electronic and electrical components, inverter power, communication bus, etc., which seriously affects the stability and reliability of shearer bus by electromagnetic interference. As the installed power continues to increase and the shearer's intelligent demand becomes higher, the electromagnetic interference of the intelligent shearer's electronic and electrical control system bus becomes more severe. At present, the wiring process in the shearer’s electrical control box is mainly based on experience. There are still no effective estimation means for the electromagnetic environment and the research is limited on the coupling model of line field transmission in the shearer’s electrical control box, causing that it cannot provide technical support for improving the bus anti-interference ability of intelligent shearer control system. Therefore, to inhibit electromagnetic interference effectively and optimize the wiring process for improving the stability of bus communication has become an important problem to be solved urgently for intelligent shearer. According to the requirements of anti-interference technology of intelligent shearer bus, the radiation interference model of the power cable in the control box of intelligent shearer is established, and the rapid estimation method of the output-power-cable electromagnetic radiation is proposed. Furthermore, the electromagnetic radiation of the output power cable of the frequency converter is analyzed, which is influenced by switching frequency, output voltage, and starting state. Then, the analysis model of the shearer CAN bus crosstalk characteristics based on the double conductor transmission line is established, the crosstalk estimation method of the shearer CAN bus based on the crosstalk influence factor is proposed, and the relationship between the crosstalk effect of bus and wiring distance, cable type, height from the ground, and other factors is studied. Based on the analysis mentioned above, a bus anti-interference optimization wiring process and a shearer bus anti-interference test visual system are developed for an intelligent shearer electric control box. To verify the feasibility of the proposed method, the bus interference test experiments are designed and carried out before and after the wiring optimization of the electric control box. The results show that the deviation degree of the CAN bus data frame waveform before and after the optimization is 0.149 3 and 0.030 5, respectively, and the disturbance rate before and after optimization is 56.07% and 35.33%, respectively.

Keywords

• intelligent shearer
• bus anti-interference
• cable electromagnetic radiation
• bus crosstalk
• arrangement of wire.