基于电压预测的永磁同步电机直接转矩控制系统研究

发布时间：2018-02-14 00:43

本文关键词： 永磁同步电机电压预测幅相补偿磁链观测混合空间矢量调制直接转矩控制　出处：《东北大学》2014年硕士论文　论文类型：学位论文

【摘要】：永磁同步电机由于其高效率、高功率/转矩密度比、高可靠性得到各行业的广泛关注。高性能的直接转矩控制技术应用于永磁同步电机,大大简化了控制结构,提高了系统动态响应性能,但同时也存在转矩波动大以及开关频率不稳定等缺点。本文以永磁同步电机直接转矩控制系统为研究对象,目标在于寻求一种简单、有效的方法来降低转矩波动。在永磁同步电机数学模型和直接转矩控制基本原理的基础上针对几种常用磁链观测器存在的缺点与不足,提出一种改进的基于带通滤波器的幅相补偿磁链观测器；为了抑制转矩脉动,提出基于电压预测的直接转矩控制方法,并以此构建基于电压预测的永磁同步电机直接转矩控制系统。在磁链观测方面,分析几种常用磁链观测器原理并给出原理性仿真,指出其在实际应用中存在的缺点与不足；在一阶低通滤波器的基础上,提出一种改进的基于带通滤波器的幅相补偿磁链观测器。带通滤波器中的高通环节用来滤除直流分量,低通环节用来观测磁链,并对由此引起的幅值和相位误差给予精确补偿；通过原理分析,仿真验证以及对比分析,充分说明改进的磁链观测器的正确性和有效性。为了抑制转矩脉动,在已有控制方法的基础上,提出了一种基于电压预测的直接转矩控制方法,利用转矩和磁链波动量预测出幅值和相位可变的电压矢量。该方法中,取消了转矩和磁链滞环比较器以及开关表,首先对传统的电压矢量选择方案做出改进,根据定子磁链位置以及不同位置的电压矢量对转矩和磁链的作用效果,把电压矢量所在平面划分成4个不同的区域；然后利用转矩和磁链的波动量大小,通过两个简单的公式来定量、实时预测电压矢量的幅值和相位角,并对所选参数进行优化分析；最后,利用混合空间矢量调制方法合成该电压矢量,在HSVM的作用下,得到了恒定的开关频率。该方法仅仅需要转矩和磁链的波动量大小,控制结构简单,不需要额外的电机参数,坐标旋转变换以及复杂的计算过程。最后,在三相逆变器硬件实验平台上,设计控制系统软硬件部分,并进行实验验证。实验结果和仿真结果基本一致,证明了改进方案的正确性及有效性。
[Abstract]:For its high efficiency, high power / torque density ratio and high reliability, permanent magnet synchronous motor (PMSM) has attracted wide attention in various industries. High performance direct torque control (DTC) technology has been applied to PMSM, which greatly simplifies the control structure. The dynamic response performance of the system is improved, but at the same time there are some shortcomings such as high torque fluctuation and unstable switching frequency. In this paper, the direct torque control system of permanent magnet synchronous motor (PMSM) is taken as the research object, and the aim is to find a simple method. Based on the mathematical model of permanent magnet synchronous motor (PMSM) and the basic principle of direct torque control (DTC), the shortcomings and shortcomings of several kinds of flux observer are discussed. An improved amplitude and phase compensation flux observer based on bandpass filter is proposed, and a direct torque control method based on voltage prediction is proposed to suppress torque ripple. The direct torque control system of PMSM based on voltage prediction is constructed. In the field of flux observation, the principle of several flux observer is analyzed and the principle simulation is given, and the shortcomings and shortcomings in practical application are pointed out. Based on the first-order low-pass filter, an improved amplitude and phase compensation flux observer based on band-pass filter is proposed. The high-pass link in the band-pass filter is used to filter the DC component, and the low-pass link is used to observe the flux. The accuracy and effectiveness of the improved flux observer are fully illustrated by the principle analysis, simulation and contrast analysis. In order to suppress the torque ripple, the amplitude and phase error caused by the proposed method are compensated accurately. Based on the existing control methods, a direct torque control method based on voltage prediction is proposed. The voltage vector with variable amplitude and phase is predicted by torque and flux fluctuation. The torque and flux hysteresis comparator and the switch table are eliminated. Firstly, the traditional voltage vector selection scheme is improved, according to the effect of stator flux position and voltage vector at different position on torque and flux. The voltage vector is divided into four different regions, and the amplitude and phase angle of the voltage vector are predicted by two simple formulas. Finally, the hybrid space vector modulation method is used to synthesize the voltage vector, and the constant switching frequency is obtained under the action of HSVM. The control structure is simple, there is no need for additional motor parameters, coordinate rotation transformation and complicated calculation process. Finally, the hardware and software of the control system are designed on the hardware experiment platform of three-phase inverter. The experimental results are in good agreement with the simulation results, which proves the correctness and effectiveness of the improved scheme.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM341

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