| Coal industry is an important energy backing to ensure people's livelihood and rapid economic development in China,and the driving system of coal machine is developing in the direction of low speed and high power.In view of the huge size of the traditional asynchronous motor and reducer for mine,which will bring great challenges to transportation,installation and maintenance,and its efficiency and power factor will be greatly reduced when running at low speed,Therefore,this paper puts forward a kind of low speed permanent magnet synchronous motor with modular mine stator(mms-pmsm),which is efficient and reliable in transmission,simple in magnetic circuit and convenient for maintenance and transportation.this paper takes 10 modular permanent magnet synchronous motors with power of 200 KW as a prototype,introduces its structure and principle in detail,simulates electromagnetic field and temperature field,and analyzes the stress and loss of end windings,mainly including the following research:Firstly,according to the special structural characteristics of stator modular permanent magnet synchronous motor,the mathematical model and working principle of the motor are analyzed.Considering that the motor shares one rotor and the stator is modularized,the arrangement of unequal span windings is adopted to realize the double decoupling of machinery and electricity,and the variation laws of voltage equation,electromagnetic torque equation,motion equation,mutual inductance and self-inductance of the motor when some modules and all modules are running are derived.According to the new modular structure of stator,the parallel power supply connection mode is proposed to improve the reliability and save the manufacturing cost of motor And adopt redundant power control and optimal efficiency control strategy to switch modules according to load rate.Secondly,the design scheme of mine stator modular permanent magnet synchronous motor is determined,and the electromagnetic field simulation analysis is carried out in the finite element software,and the magnetic field distribution of independent,symmetrical and all modules in operation is analyzed.Then,based on the image method,the boundary condition of the end stress is analyzed,and the electromagnetic force of the end winding of the unit module stator in Ansoft is analyzed by numerical calculation method,so as to obtain the end stress of each phase winding and study the force situation of the end winding.The axial and radial temperature field distribution of the motor is analyzed based on the equivalent thermal path method.The core loss separation method,copper loss and mechanical loss model are used to analyze the heat source of mine stator permanent magnet synchronous motor,and the thermal path model is established.The electromagnetic calculation module in Motor CAD analyzes the loss values of each part under rated,no-load and overload conditions,which provides a basis for solving the motor temperature field.Then,the temperature field is analyzed by thermal calculation model,and the reliability of motor temperature rise under various working conditions is verified.Finally,research on the control theory of multi-unit split permanent magnet synchronous motors for mines.Compared with conventional control strategies,an improved optimal efficiency control strategy is proposed.The redundant power control strategy is adopted to switch the units on and off according to the load rate to improve The range of the high-efficiency zone of the motor. |
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