感应电机直接转矩控制算法转矩脉动抑制方法的研究

发布时间：2018-04-13 18:46

本文选题：感应电机 + 直接转矩控制　；参考：《吉林大学》2017年硕士论文

【摘要】：由于感应电机具有结构简单、价格低廉、环境适应性强等优点,在工农业生产制造、军事领域等各行各业都占据着非常重要的应用地位,针对感应电机的调速系统的研究得到广泛关注。直接转矩控制作为一种新兴的交流电机控制技术,以其控制手段直接,响应速度快等优点,与其它控制策略相比有明显优势。本文选择感应电机为研究对象,对基于圆形磁链的直接转矩控制系统进行建模,并针对转矩脉动大的问题进行分析并提出改进方案,从而对控制系统进行优化。在传统直接转矩控制系统中,电压矢量的选择受滞环比较器宽度的影响,同时由于每个采样周期矢量电压只能从有限的几个电压中选择,导致了开关频率不稳定、选择的电压矢量不是最优值等问题。本文结合空间矢量脉宽调制技术对控制系统进行改进,把电动机和逆变器看作一个整体,通过使电动机的磁链幅值基本保持恒定,实现了对定子磁链平滑调节,同时降低了转矩脉动。针对SVPWM系统中作用时间溢出问题提出补偿措施,并通过仿真实验确定补偿系数k的取值。为了得到更加精确的电压空间矢量以满足转矩磁链要求,本文结合无差拍控制思想重新设计磁链与转矩控制器,通过对转矩无差拍和磁链无差拍的要求进行分析计算得出期望电压矢量,将得到的期望电压矢量作为SVPWM模块的输入,从而对电机进行控制,使得在下一个采样周期实际转矩和磁链可以有效的跟踪上给定转矩和磁链,降低误差带来的波动。同时通过分析定子压降对期望电压值的影响,提出了新的控制方案。通过分析误差值,验证其有效性。在MATLAB/Simulink软件环境中建立感应电机直接转矩控制系统模型。将改进方案在仿真模型中以建立新模块的方式展现出来,通过对改进前后电磁转矩,定子磁链等仿真结果的比较与分析,得出改进后直接转矩控制系统的定子磁链轨迹控制较为平滑,对转矩脉动也有一定的抑制效果,验证了改进方案的可行性。
[Abstract]:As induction motors have the advantages of simple structure, low price and strong environmental adaptability, they occupy a very important application position in various industries such as industrial and agricultural production, military field and so on.The research on the speed regulation system of induction motor has been paid more and more attention.As a new AC motor control technology, direct torque control (DTC) has obvious advantages over other control strategies because of its advantages of direct control and fast response.In this paper, the induction motor is selected as the research object, the direct torque control system based on circular flux chain is modeled, and the problem of large torque ripple is analyzed and an improved scheme is put forward to optimize the control system.In the traditional direct torque control system, the choice of voltage vector is affected by the width of hysteresis comparator, and because the vector voltage of each sampling period can only be selected from a limited number of voltages, the switching frequency is unstable.The selected voltage vector is not optimal and so on.In this paper, the space vector pulse width modulation technology is used to improve the control system. The motor and inverter are regarded as a whole. By keeping the flux amplitude of the motor basically constant, the stator flux is adjusted smoothly.At the same time, the torque ripple is reduced.To solve the problem of action time spillover in SVPWM system, the compensation measures are put forward, and the compensation coefficient k is determined by simulation experiment.In order to obtain more accurate voltage space vector to meet the demand of torque flux, this paper redesigns the flux and torque controller with the idea of deadbeat control.The expected voltage vector is obtained by analyzing and calculating the requirements of torque beat and flux linkage, and the expected voltage vector is used as the input of SVPWM module to control the motor.It can effectively track the given torque and flux in the next sampling period and reduce the fluctuation caused by the error.At the same time, by analyzing the influence of stator voltage drop on the expected voltage value, a new control scheme is proposed.The validity of the method is verified by analyzing the error value.The direct torque control system model of induction motor is established in MATLAB/Simulink software environment.The improved scheme is presented in the simulation model by establishing a new module. Through the comparison and analysis of the simulation results before and after the improvement, such as electromagnetic torque, stator flux linkage, etc.It is concluded that the stator flux locus control of the improved direct torque control system is smooth, and the torque ripple is restrained to a certain extent, which verifies the feasibility of the improved scheme.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP273;TM346

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