基于DSP的三相异步电机绕组变匝数调速系统研究

发布时间：2018-06-01 19:01

本文选题：定子绕组变匝数 + 间接矢量控制　；参考：《浙江大学》2017年硕士论文

【摘要】：在很多交流电机驱动场合中,如电动汽车、机床主轴等,既需要电动机在低速时输出较大的转矩,又需要电动机有较宽的调速范围。然而在应用传统方法在电机的恒功率区进行弱磁调速时,电机的最高转速受到额定电压和变频器功率等级的限制。针对上述问题,绕组切换不失为一种好的方法。本文首先分析总结了一些常用的绕组切换方法,并以三相异步电机为例,重点介绍了安川公司提出的变绕组扩速方法,该方法通过改变定子绕组匝数来降低反电动势从而拓宽调速范围。由于在采用该方法进行绕组切换的过程中会引起电机参数突变,目前还缺乏有效的暂态过程分析手段,无法应对可能的电流冲击、转矩波动、甚至功率器件损毁等情况。于是本文基于场路耦合仿真的解决思路,通过使用Maxwell与Simplorer软件工具对绕组切换的暂态过程进行联合仿真,解决多抽头电机建模和控制环路设计等问题。仿真结果与稳态分析一致,暂态结果的准确性需要通过实验进一步验证。此外,采用安川的变绕组方法,在系统切换前的瞬间,电机的输出转矩不得超过该速度所对应的最大输出转矩的一半,同时该文献作者对切换后如何利用反电动势的提升空间没有做具体讨论。针对以上问题,本文提出了具体的改进方案,即在励磁电流恒安匝数原则切换后,通过提升励磁电流(对应间接矢量控制)或端电压(对应开环V/f控制)至额定水平,在短时间内完成反电动势和励磁的过渡,此后电机可以继续弱磁调速。为了验证联合仿真和上述的改进方案,搭建了基于DSP的三相异步电机绕组变匝数调速系统实验平台,分别采用开环V/f控制和转子磁场定向的间接矢量控制作为基本控制策略,完成了保持励磁电流安匝数不变的绕组切换。实验结果表明,使用安川的变绕组方法可以较好的抑制暂态电流冲击和转矩波动,实验波形与仿真结果一致。当使用改进方法时,可以通过改变励磁电流(或端电压)给定值的上升速度来调节反电动势和励磁的上升时间,使该过程降低至几十毫秒以内。
[Abstract]:In many AC motor driving situations, such as electric vehicles, machine tool spindle and so on, it is necessary for the motor to output large torque at low speed and to have a wide speed range. However, the maximum speed of the motor is limited by the rated voltage and the power level of the inverter when the traditional method is used to adjust the weak magnetic field in the constant power region of the motor. To solve the above problems, winding switching is a good method. In this paper, some commonly used winding switching methods are analyzed and summarized firstly, and taking three-phase asynchronous motor as an example, the paper mainly introduces the variable winding expansion method proposed by Yanchuan Company. This method reduces the back EMF by changing the number of stator winding turns and widens the speed range. Due to the sudden change of motor parameters during winding switching using this method, there is still a lack of effective transient process analysis method, which can not cope with possible current shocks, torque ripples and even power device damage. Therefore, based on the solution of field-circuit coupling simulation, by using Maxwell and Simplorer software tools to simulate the transient process of winding switching, the problems of multi-tap motor modeling and control loop design are solved. The simulation results are consistent with the steady-state analysis, and the accuracy of transient results needs to be further verified by experiments. In addition, the output torque of the motor should not exceed half of the maximum output torque corresponding to the speed of the motor at the moment before the system switching, using Yanchuan's variable winding method. At the same time, the author does not discuss how to use the lifting space of the backEMF after switching. In view of the above problems, this paper puts forward a specific improvement scheme, that is, after switching the principle of constant ampere turn of excitation current, the excitation current (corresponding to indirect vector control) or terminal voltage (corresponding to open loop V / F control) to the rated level, In a short time to complete the back EMF and excitation transition, after which the motor can continue to weak speed. In order to verify the joint simulation and the improved scheme mentioned above, an experimental platform of variable turn speed control system for three-phase asynchronous motor windings based on DSP is built. The open loop V / f control and the rotor flux oriented indirect vector control are used as the basic control strategies respectively. The winding switching is completed to keep the ampere-turn number of excitation current unchanged. The experimental results show that the transient current shock and torque ripple can be well suppressed by using Yanchuan's winding changing method. The experimental waveform is consistent with the simulation results. When the improved method is used, the rise time of the backEMF and excitation can be adjusted by changing the rising speed of the given value of excitation current (or terminal voltage), so that the process can be reduced to less than tens of milliseconds.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM343.2

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