电动叉车异步电机直接转矩控制系统研究与设计

发布时间：2018-05-11 15:13

本文选题：异步电机 + 直接转矩　；参考：《东北大学》2012年硕士论文

【摘要】：随着交流动力控制逐渐成为电动叉车的主要技术,对电动叉车用交流驱动系统的要求也越来越高,精度高、响应快、计算简单永远都是电动机控制系统追求的目标。直接转矩控制(DTC)技术是继矢量控制技术之后,一种新型高性能的交流调速传动的控制技术。直接转矩控制在定子坐标系下计算和控制交流电机的转矩,采用定子磁场定向控制,直接对逆变器的开关状态进行最佳的控制。它以其简洁明了的结构,优良的静、动态性能,受到了广泛的关注。本文介绍了异步电机直接转矩控制的基本原理,从异步电机数学模型入手,通过对逆变器开关状态分析得到空间电压矢量,给出了直接转矩控制系统的基本结构,并对各工作单元进行了介绍。根据磁通和转矩自控制原理分析了空间电压矢量的正确选择方法。通过对传统直接转矩控制系统中的转矩脉动问题的深入分析,经转矩模型的推导分析影响转矩脉动的主要因素。分别研究了基于传统直接转矩减少转矩脉动途径的特点,并对改善低速性能做了相应研究。本文提出了基于空间电压矢量调制(SVPWM)的直接转矩控制策略。通过仿真结果表明将空间矢量调制技术加入直接转矩控制策略后,控制系统在保留传统DTC动态性能的情况下,减小了转矩脉动和电磁噪声。该方案简单可靠,观测精度高。本文采用功率MOSFET器件并联方案,设计逆变器的主回路、驱动电路和缓冲电路,对缓冲电路及主回路电路进行系统仿真及主回路和缓冲电路各参数进行优化。分析并联的功率MOSFET的均流问题,对MOSFET管并联均流进行系统仿真,研究其均流特性。并设计以DSP为核心的控制电路和检测电路实现低压大电流逆变器实验平台搭建。试验结果验证了SVPWM控制策略应用到实际系统中的可行性。
[Abstract]:With the AC power control gradually becoming the main technology of electric forklift, the requirement of AC drive system for electric forklift is more and more high, the precision is high, the response is fast, and the simple calculation is always the goal of the motor control system. Direct torque Control (DTC) is a new type of high performance AC speed control technology after vector control. Direct torque control (DTC) is used to calculate and control the torque of AC motor in stator coordinate system. Stator flux oriented control is adopted to directly control the switching state of inverter. Because of its simple and clear structure, excellent static and dynamic performance, it has received wide attention. This paper introduces the basic principle of direct torque control (DTC) of asynchronous motor. Starting from the mathematical model of asynchronous motor, the space voltage vector is obtained by analyzing the switching state of the inverter, and the basic structure of the DTC system is given. Each work unit is introduced. According to the principle of flux and torque self-control, the correct selection method of space voltage vector is analyzed. By analyzing the torque ripple problem in the traditional direct torque control system, the main factors influencing the torque ripple are analyzed by the derivation of the torque model. The characteristic of reducing torque ripple based on traditional direct torque is studied, and the improvement of low speed performance is studied. A direct torque control strategy based on space voltage vector modulation (SVPWM) is proposed in this paper. The simulation results show that the torque ripple and electromagnetic noise of the control system can be reduced by adding the space vector modulation technology into the direct torque control strategy while retaining the dynamic performance of the traditional DTC. The scheme is simple and reliable, and the observation accuracy is high. In this paper, the main circuit, drive circuit and buffer circuit of the inverter are designed by using the parallel scheme of the power MOSFET device. The system simulation of the buffer circuit and the main circuit are carried out, and the parameters of the main circuit and the buffer circuit are optimized. The current sharing problem of parallel power MOSFET is analyzed, and the system simulation of parallel current sharing of MOSFET tube is carried out, and its current sharing characteristics are studied. The control circuit and detection circuit based on DSP are designed to realize the experiment platform of low voltage and large current inverter. The experimental results verify the feasibility of applying the SVPWM control strategy to the actual system.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH242

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