Design And Analysis Of Low-speed High-torque Permanent Magnet Motor Based On Modulated Concentrated Winding

With the rapid development of science and technology,the demand for belt conveyors in mining and metallurgy industries is increasing.In order to avoid damage to the conveyed material,the belt conveyor needs to be conveyed smoothly,and there is no relative movement between the material and the conveyor belt.The drive of traditional belt conveyors mostly adopts the matching method of motor and magnetic gearbox and other transmission devices.Although this combination can increase the torque density,it has the problems of large volume,large noise and large torque pulsation.To solve the above problems,this paper proposes a modulated concentrated winding method,and designs a 315 kW winding modulated permanent magnet motor based on this modulation method.Connecting the belt conveyor directly to the winding modulated permanent magnet motor can improve torque ripple and increase Torque density.This paper has carried out research work on the winding modulated permanent magnet motor,the main contents are as follows.First of all,the relevant principles and structure of the magnetic field modulation type permanent magnet motor are explained,its advantages and disadvantages are discussed,and a modulation type concentrated winding method is proposed.The working principle of the motor using the modulation type concentrated winding method is analyzed.The coils on each stator tooth are connected in series and in parallel according to a certain rule to realize flexible changes in the number of poles of the armature magnetic field.By this method,the modulation function can be realized and the modulation ratio is also greater.The modulation type concentrated winding winding method is convenient for winding in engineering,and can reduce the size of the coil,shorten the length of the motor end and increase the torque density.Secondly,according to the technical requirements of the motor,the winding modulated permanent magnet motor was designed,and its topology and electromagnetic parameters were determined.In order to compare the performance of the winding modulation type permanent magnet motor designed in this paper,under the same technical requirements,a magnetic field modulation type permanent magnet motor is designed.Then,the finite element method is used to simulate the electromagnetic performance and losses of the two motors,and the magnetic field distribution and losses of the motors are analyzed.Through the analysis of the simulation results of the two motors,the rationality of the motors is verified.The characteristics of the winding-modulated permanent magnet motor are that the torque ripple is smaller and the torque density is greater.Finally,in order to verify the rationality of the temperature distribution of the designed motor,the casing and cooling water circuit were drawn for the winding-modulated permanent magnet motor using drawing software,and a three-dimensional model of the temperature field simulation of the winding-modulated permanent magnet motor was established.Through the previous theoretical analysis,the establishment of a three-dimensional model and the setting of solution conditions,the finite element software is used to calculate and analyze the temperature field of the winding modulated permanent magnet motor designed in this paper.The simulation results show that the temperature distribution of the motor is reasonable,and the risk of irreversible demagnetization caused by the temperature rise of the permanent magnet is low,which is conducive to long-term stable operation.