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Using gray theory established entropy weight and gray association model in analyzing the mostly infection factors of coal and gas outburst, entropy theory was used to calculate the weights of contamination. Analysis of sample data, in accordance with the order of gray correlative degree, it is found out the closest relations with the outstanding master factors to identify the most likely sensitive indicators to improve the accuracy of coal and gas outburst forecast prominently.

Phase-shifting reactor (PSR) can be used to solve the harmonic problems caused by rectifiers. In this paper, according to the active power balance principle, the relationships among the DC current of the loads, the currents of power supply side, and the capacity of core limb are built, the product specification of winding and core are obtained. Meanwhile, the coupled field-circuit method based on Simplorer and Maxwell, and the circuit method based on MATLAB/Simulink are discussed by the simulation of the 6-phase rectifier system. The results show that the designed PSR meets the requirement well, and suppresses the harmonic of power supply side effectively.

Rectifier transformer is typical ac-dc converter for improving power quality by reducing the harmonic in ac mains and ripples in dc output. The design of rectifier transformer is difficult because it originates from the experience of designers. So a designer who is lack of experience would result in a waste of material and cost. In order to reduce the manufacturing cost of rectifier transformer, this paper employs the Genetic algorithm (GA) to optimize the size of iron core which is a main component of rectifier transformer. Three parameters are selected as optimization variables and the target of the optimization is to minimize the weight of iron core. The result shows that the weight of the iron core drops down greatly compared with a rectifier transformer which is designed by the traditional empirical formula. Finally, the simulation of optimization shows that the function of rectifier transformer is also achieved.