Research On Speed Regulation Characteristics Of Permanent Magnet Eddy Current Governor With Conductivity Regulation Under Constant Torque Load

When the motor directly drives continuous conveying equipment in coal mines,such as scraper conveyors and belt conveyors,with constant torque loads,there are often problems such as difficulty in heavy load starting,vibration impact,multiple machine power imbalance,and inability to overload protection and speed regulation operation.However,existing mining conveying equipment drive speed regulation technology cannot simultaneously meet the multi-functional requirements of constant torque load speed regulation.This paper proposed a new type of permanent magnet eddy current speed control technology for constant torque loads.Its basic principle is to achieve the above goals by adjusting the conductivity of the conductor layer of the cylindrical permanent magnet eddy current speed controller.This article conducted the following research:(1)Introduction to the structural design and principle of a new type of cylindrical permanent magnet eddy current governor.The basic structure of a permanent magnet eddy current governor with gradually changing conductivity was designed,and its working mechanism was introduced.A conductor cylinder axial segmented connection method was proposed to achieve the gradual change of conductivity in the conductor layer,laying the foundation for the establishment of transient torque calculation models of the governor and the analysis of speed regulation characteristics in the future.(2)Electromagnetic field analysis of a new type of governor.Based on the layer model theory,a transient torque calculation model for a new type of governor was established using the separation of variables method.The equivalent conductivity function was established,and the mathematical relationship between the output speed of the governor and the position of the magnet disk was derived.The transfer efficiency calculation formula of the governor was given,and compared with the results of threedimensional electromagnetic finite element simulation.The results showed that the model can be used for characteristic analysis of the governor.(3)Optimization method for structural parameters of a new type of governor.In order to solve the problem of excessive axial length of the equipment in the practical application of the new governor,while ensuring the performance of the equipment,the structural parameters of the governor are used as design variables,and the optimization objectives are to maximize overturning torque,minimize the use of permanent magnets,and minimize the axial length of the governor.A new governor structural optimization model is established.Single objective and multi-objective optimization design of the governor was carried out using genetic algorithm.The results show that the algorithm has good optimization effects and can provide guidance for the structural optimization design of subsequent governors.(4)Analysis of the speed regulation characteristics of a new type of governor.Analyzed the impact of changes in conductor layer conductivity on the transmission characteristics of the governor;Simulate the variation of equivalent conductivity and obtain the variation law of equivalent conductivity;Design a reasonable conductivity distribution and analyze the speed regulation characteristics and transmission efficiency of the constant torque load regulator,and use electromagnetic finite element method simulation to verify the effectiveness of the theoretical results.The analysis results show that changes in the conductivity of the conductor cylinder will alter its transmission characteristics;The blocking point will decrease with the decrease of conductivity,and the overturning torque remains constant;The segmented structure can achieve a gradual change in the conductivity of the conductor layer during speed regulation.(5)Simulation experiment of a new type of governor transmission system.A constant torque load permanent magnet eddy current speed control simulation system was established,and its speed control principle was analyzed.Its dynamic model was established.Speed control operation and overload protection simulation experiments were conducted on the speed control system,and the working curve of the new type of speed controller was obtained.The results show that the system can achieve startup,speed regulation operation,and overload protection for constant torque loads,verifying the availability of permanent magnet eddy current speed regulation technology under constant torque loads.