【作者】 刘欢；

【导师】 任彧；

【作者基本信息】 杭州电子科技大学 ， 计算机系统结构， 2009， 硕士

【摘要】 随着现代物流技术的发展,人们对叉车产品的要求越来越高。以交流电机为核心的交流驱动系统由于效率高、可靠性强、体积小、结构简单、调速范围宽、低速恒转矩、高速恒功率、维护成本低,将引领新一轮电动叉车技术革命,成为叉车发展的趋势。同时,电子技术的发展及新型控制理论的成熟也使得交流伺服控制系统由过去的模拟控制转向全数字控制。数控伺服电机控制系统可以对电机实现精确的力矩控制,速度控制和位置控制,其性能、反应速度和稳定性都明显优于直流电动机伺服系统。尤其是采用了高性能稀土永磁材料的伺服电机,其出力大,惯性小,起停动态性能特别好,有助于提高生产率和电动叉车质量。越来越多电动叉车设备中采用这种省电、免维修、低噪音的新型电机控制系统已是大势所趋。数控交流伺服电机控制系统正在逐步取代传统直流电动机、步进电机伺服控制系统而成为电动叉车驱动系统的主流技术。论文首先分析了永磁同步电机(PMSM)的原理和模型,包括PMSM的结构、工作原理和数学模型,并对伺服系统的矢量控制理论进行了系统的分析研究。选用了Id=0的磁场定向矢量控制(FOC)方法作为本系统的主要控制理论基础。它可以实现对电机交直轴之间的解耦,具有转矩控制的线性特点,能够获得比较平稳的输出转矩,达到比较宽的调速范围。随后,根据控制原理分析系统各组成部分的构成,以及伺服系统的工作流程。在控制理论上,介绍了传统PID和数字PID控制算法,重点分析了SVPWM控制算法和一种死区补偿策略。对电压源型三相逆变器死区效应的发生机理进行了详细分析,根据电压空间矢量图将三相电压分成6个区域,并采用时间补偿方法在各区域中按电流方向对三相输出电压进行补偿。试验结果表明,该补偿方法能有效改善由于死区效应引起的电机电流波形畸变,提高了逆变器的输出性能。本文讨论了基于DSP的电动叉车交流伺服控制系统的设计与研究,提出了一套基于TMS320F2812 DSP数字信号处理器为主控芯片,及并联多个低压大电流的MOSFET作为功率驱动模块的系统设计方案,并且详述了关键部分的功能与实现方法。系统设计了较为完善的保护功能:控制器中增加了外围过压、过热和过流保护;功率模块中采用光耦隔离屏蔽措施,提高抗干扰能力,保障系统安全可靠运行。在软件实现上,采用了模块化设计思想以及系统主程序和中断服务程序的结构,并介绍了几个主要子程序的实现过程。最后在理论的基础上对系统进行Simulink仿真。通过实验平台,对电机低速运转进行了测试,结果证明该系统稳定性好、各参数符合设计要求。测试结果表明整套控制系统能够满足现代数控电动叉车的工业需求,有较高的性能价格比,具备良好的市场前景。更多还原

【Abstract】 With the development of modern logistics technology, people have higher and higher requirement on forklift products. AC motor as the core of AC drive system will lead a new wave of electric forklift technology revolution and become forklift truck trends because of high efficiency, reliability, small size, simple structure, wide speed range, low-speed constant torque, high-speed constant-power and low maintenance costs. Meanwhile, the development of electronic technology and maturity of new control theory also makes AC servo control system from the previous analog control to an all-digital control. The digital servo motor control system can achieve precise torque control, speed control and position control, and much better than DC motor servo systems special in quickly reaction and stability. Especially using the high energy Rare-earth permanent magnets motor, the servo system have performance in torque output, small force of inertia, fast dynamic response in start-stop mode, which help promote production efficiency and forklift quality. It become the irresistible trend that the low power consume, maintenance-free, low noise motor control system is more and more used in Electric Forklift Equipments. The NC (Numerical Control) AC servo motor control systems are gradually replacing traditional DC motor servo control system and become the mainstream technology in the sewing machine drive system.First of all, the principle and model of Perrnanent Magnet Synchronous Motors (PMSM) are given, including the structure,works and mathematical model. Then the vector control theory of servo system is analyzed systematically and the Field Oriented Control(FOC) theory that d-axis current is equal to zero is selected as the main theoretical basis. It can realize the electrical decoupling between the the d and q axe with a linear torque control characteristics, and obtain relatively steady output of torque to achieve relatively wide speed range. Subsequently, according to the control principle, the composition of the various components and workflow of the servo system are analyzed.In the control theory, the traditional PID control algorithm and the traditional PID control algorithm are introduced with the emphasis on SVPWM control algorithm and a kind of dead-time compensation strategy. Mechanism of dead-time effect on the three-phase voltage source inverter is analyzed in detail. According to voltage space vector, three-phase voltage is divided into six regions and is compensated by the method of time compensation in various regions according to current direction. The results show that the compensation method can effectively improve motor current waveform distortion causing by the effect of dead zone, and enhance the output performance of the inverter.The design and research of the electric forklift AC servo control system are discussed based on DSP. A set of hardware system design is presented out based on the TI TMS320F2812 DSP digital signal processor chip as a master, and multiple parallel low-voltage high-current of the MOSFET as the power drive module. The method and realization about some key segments are elaborated. System designs a more comprehensive protection functions. For example, the external overvoltage, overheating and overcurrent protections are added in the controller design. Optocoupler isolators shielding measures are used in the power module to raise the anti-jamming capability to ensure the system safe and reliable operation. In software design, the idea of modular design method and the structure of system main program, the interrupt service program are adopted, and implementation processes of some sub-programs are proposed.Finally, this system is simulated by Simulink on the basis of the theory. The experiment platform is tested on low-speed operation of the motor. The results show that the system has good stability and the parameters are in line with design requirements. Test results show that the entire control system can meet the modern numerical control electric forklift industrial demand, and it has a high cost performance with good market prospects.更多还原