球磨机直驱用超低速大转矩永磁同步电动机研究

发布时间：2018-05-26 11:29

本文选题：超低速大转矩 + 极槽比　；参考：《沈阳工业大学》2017年硕士论文

【摘要】：球磨机传动系统,是典型的低速大转矩系统,主要采用传统异步机减速机的驱动模式。本文采用永磁同步电机直接驱动球磨机运转,替代原有异步电机-减速机驱动模式;永磁电机直接驱动球磨机运转必然带来电机功率、体积、起动转矩等参数较大;中小型电机中无需考虑的问题,在设计大直径大功率兆瓦极电机需要考虑进去。针对额定功率3550k W,额定转速16r/min球磨机直驱用永磁同步电动机进行电磁设计。通过对比10极12槽和8极12槽配合下PMSM性能参数,总结低速大转矩槽选取规律,选取10极12槽单元电机极槽配合;定子槽选用开口槽,扁线绕成的分为双排的成型线圈,永磁体采用切向式结构摆放方式,充分利用磁阻转矩,提高功率密度,获得较大的过载倍数。对球磨机直驱用超低速大转矩永磁同步电动机初步方案进行进一步优化。对电机进行长径比优化;保持定子外径不变,观察热负荷、转矩密度和永磁体用量变化趋势,优化定转子冲片尺寸,确定当电机气隙直径5000mm,铁心长1400mm得到电机体积和转矩密度最优值;确定气隙之后,保持电流密度不变,优化定子槽型得到转矩密度最优值;磁极冲片最大最小气隙之比为2.2倍和磁极肩角18度使气隙磁密波型接近正弦;对比电励磁同步电机与永磁同步电机最大最小气隙比值,电励磁同步电机最大最小气隙之比通常取1.5,而永磁同步电机最大最小气隙之比在2.2-2.4之间比较合理。建立球磨机用永磁同步电动机偏心模型,通过分析气隙磁密表明,随着偏心率变大,气隙在空间上不再对称,气隙磁密中产生偶次谐波,以二次谐波最明显;动态偏心情况下齿槽转矩引入了高次谐波,会导致电机转矩高频脉动,并且在动态偏心发生前期,齿槽转矩增加的并不明显,当动态偏心达到一定程度时,幅值迅速增大。转子不同偏心状态下,对电机的铁心损耗、转子部分涡流损耗进行了仿真分析表明,动、静态偏心对铁心损耗的影响情况相似,而动态偏心的涡流损耗不像静态偏心变化明显;电机静态偏心时,电机转矩波动变化不大,并有降低转矩波动振幅的趋势,而动态偏心会引起转矩波动振幅增加,动态偏心会增加转矩波动。
[Abstract]:The drive system of ball mill is a typical low speed and large torque system, which mainly adopts the drive mode of traditional asynchronous reducer. In this paper, the PMSM is used to drive the ball mill directly instead of the original drive mode of asynchronous motor and reducer, the direct drive of the ball mill by the permanent magnet motor will inevitably bring about large parameters such as motor power, volume, starting torque, etc. The design of large diameter megawatt pole motor needs to be taken into account in the design of large-diameter high-power megawatt motor. Electromagnetic design of permanent magnet synchronous motor (PMSM) for rated power 3550kW and rated speed 16r/min ball mill is carried out. By comparing the performance parameters of PMSM with 10 pole 12 slot and 8 pole 12 slot coordination, the selection rule of low speed and large torque slot is summarized, and 10 pole 12 slot unit motor pole slot matching is selected, the stator slot is composed of open slot, flat wire is wound into two rows of forming coils, The permanent magnet adopts the tangential structure to make full use of the magnetoresistive torque to increase the power density and obtain a large overload multiple. The primary scheme of super low speed and large torque permanent magnet synchronous motor for direct drive of ball mill is further optimized. The length to diameter ratio of the motor is optimized, the stator outer diameter is kept constant, the changing trend of heat load, torque density and permanent magnet is observed, and the size of stator and rotor punches is optimized. The optimum value of motor volume and torque density is obtained when the air gap diameter is 5000mm and the core length is 1400mm. After the air gap is determined, the current density is kept constant, and the optimal torque density is obtained by optimizing the stator slot type. The ratio of maximum and minimum air gap of magnetic pole punch is 2.2 times and the angle of magnetic pole shoulder is 18 degrees to make the airgap magnetic dense wave close to sinusoidal. Compared with the ratio of maximum and minimum air gap of electrically excited synchronous motor and permanent magnet synchronous motor, The ratio of maximum and minimum air gap of electroexcitation synchronous motor is usually 1.5, while that of permanent magnet synchronous motor is between 2.2-2.4. The eccentric model of permanent magnet synchronous motor (PMSM) for ball mill is established. The analysis of air gap magnetic density shows that with the increase of eccentricity, the air gap is no longer symmetrical in space, and even harmonics are produced in the air gap magnetic density, the second harmonic is the most obvious. In the case of dynamic eccentricity, high order harmonics are introduced into the grooving torque, which will lead to the high frequency ripple of the motor torque. In the early period of the dynamic eccentricity, the increase of the slotting torque is not obvious. When the dynamic eccentricity reaches a certain degree, the amplitude increases rapidly. The simulation analysis of rotor core loss and rotor eddy current loss under different eccentricity shows that the influence of dynamic and static eccentricity on core loss is similar, but the dynamic eccentricity eddy current loss is not as obvious as static eccentricity. When the motor is static eccentricity, the torque ripple of the motor changes little, and has the tendency of decreasing the amplitude of the torque wave, while the dynamic eccentricity will cause the increase of the amplitude of the torque wave, and the dynamic eccentricity will increase the torque wave.
【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH69;TM341

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