Study And Design Of Feed Switch Based On Permanent Magnetic Operating Mechanism

China has rich coal resources. The dominant role of coal in China’s energy structure will not be changed within a short period of time. However, pressed by environmental protection, it is imperative to reduce high coal consumption and pollution during the production process. This means a higher requirement of digitalization, intelligentization and efficiency of China’s coal mining. Besides, due to harsh environment, damp air and huge load fluctuations under the coal mine, faults including power leakage, overcurrent, overvoltage and undervoltage might easily be triggered. If the faults above are not discovered and handled immediately, serious accidents might be caused. Therefore, it is of vital significance for China’s coal mine industry to design a high-performance feeder switch for mining use.This paper has introduced the current situation and research trend of mining feeder switch at home and abroad, and carried out the analysis and discussion of various power supply faults and protection principle according to the characteristic of the small current grounding system under the coal mine. Based on this, a full-functional mining feeder switch protection device is further researched and designed.Firstly, this paper analyzed the commonly-seen faults occurring to the power supply system. Based on the practical situations and characteristics of various power supply faults, this paper puts forward a corresponding feasible protection plan. Realization of the optional power leakage protection plan through the CAN bus communication between various feeder switches improves the system reliability. The adoption of the permanent magnetic mechanism as the executing mechanism optimizes the overall performance of the feeder switch.Secondly, fast Fourier transform(FFT) and local mean decomposition(LMD), two algorithms for collection and analysis of the system’s electric parameters, have been analyzed. In view of practical situations, MATLAB and PSCAD are employed to conduct simulation and research of the two algorithms. Algorithm parameters are properly chosen according to system requirements.Afterwards, the overall design of the system software and hardware is completed. In terms of hardware, TMS320F28335 is adopted as a main control chip. Combining various digital chips, the author properly designs various circuit parameters. Under the prerequisite of no effect on the functions, the derating design is adopted so as to guarantee the hardware reliability for long-term system operation. In terms of software, C language and assembly language are combined to finish the system program design and realize various protection functions.At last, according to existing conditions of the lab, experiments related to system functions are conducted. The results suggest that the feeder switch designed in this paper can well realize the expected functions. Meanwhile, some suggestions are provided based on the deficiencies.