【作者】 彭魏臻；

【导师】 麻红昭；

【作者基本信息】 浙江大学 ， 化工过程信息工程， 2007， 硕士

【摘要】 目前，袋泡茶受到人们的青睐，茶叶滤纸的需求旺盛。然而茶叶滤纸的定型工艺仍然使用传统的油加热和蒸汽加热烘缸。随着近些年能源紧缺现象的加剧以及人们环保意识的增强，各个工业部门都在不断改造老旧的传统造纸加热设备，开发节能高效、绿色环保的新型造纸设备。“感应加热”方案是一种理想的加热方式，具有热效率高、加热均匀、安全、自动化程度高等特点，在钢铁冶炼、汽车制造等行业已有成功应用。本文的创新点主要是将“感应加热”技术应用到造纸工艺设备的开发中。基于此方案，设计和实现了一个直径1400 mm，宽1400mm的茶叶滤纸定型用小型感应加热烘缸设备，并利用SIEMENS S7-200系列PLC，开发出一套成本低、控制精确、操作方便的控制系统。经过近10个月的运行，电磁感应烘缸完全可以满足茶叶滤纸生产工艺的要求，性能稳定，节能效果明显，可以作为传统烘缸的替代产品。本文从电磁感应加热电源的原理，定型机各功能组件，PLC控制系统的选型、构建及控制策略实施等几个方面来对整个系统进行阐述，内容包含：◆分析比较了常用的并联型和串联型谐振电源及特点，选择后者为感应加热烘缸的电源结构；简要介绍了PWM&PFM调功方法尤其容性PWM&PFM方法，找出了功率与相位角φ及角频率ω之间的关系；详细分析增加了无损缓冲器件的逆变回路的换流过程；简要介绍了电路启动和控制的原理。◆介绍了定型机系统的机械组成，描述了各个组件的作用；分别介绍了走纸同步、温度控制和操作台三个PLC控制子系统实现的功能。◆介绍了S7-200系列PLC控制器、通讯、控制系统硬件选型原则、数字滤波算法、前馈控制和反馈控制控制策略；列出了本项目三个控制子系统的硬件组态，介绍了在PLC编程中广泛采用的增量式数字PID算法和几种改进型的PID算法；使用现场采集的实时图线，详细分析了走纸同步系统采用的带边界失效的变比例增益、变积分时间的PI控制策略，和温度控制系统采用的常规PI策略控制的工程实施。更多还原

【Abstract】 The requirement for teabag paper increased rapidly as people’s increasing favor on teabag, while teabag paper molding technology still uses traditional papermaking equipments such as Hot Oil Cylinder Dryer and Stream Cylinder Dryer in many paper mills domestically and internally. With the growing shortage of energy and the development of people’s consciousness to protect environment, many factories are improving their old papermaking equipments and developing new, efficient, green facilities."Induction Heating" is appropriate technique, as it’s safe, efficient, uniformity for heating, and highly automotive. In addition, it has been used in smelting and automobile industry successfully. The innovation of this paper is to apply "Induction Heating" to paper-making cylinder dryer. Based on this idea, a medium-sized electromagnetic induction heating cylinder dryer for teabag paper molding was designed and manufactured, which has a diameter of 1400 mm and a width of 1400 mm. Besides, by using SIEMENS S7-200 serial PLC products, control systems were developed, with low-cost, high degree of accuracy and convenient operation. After continual run of nearly 10 months, it works stably, meeting the requirements of production and saving energy apparently, can replace the traditional hot-oil and stream cylinder dryers.This thesis expounds the process of developing induction heating dryer system, including the elements of induction-heating power supply, design of cylinder dryer, functions of paper molding machine system components, selection of PLC control system modules, control algorithm and project implementation, as listed below:analyze of two types of inverter structure: supply-parallel mode and serial mode, compare their features respectively, choose the latter one as the power structure for paper molding cylinder dryer; introduce PWM&PFM method for capacity controlling especially the capacitive PWM&PFM method, deducted of the relationship among the power, the phase-angle, and angular-frequency; make a detailed explain ofcurrent shifting processes of inverter circuit with lossless buffer devices; take an overview of start-up and control circuit.Make an introduction of the mechanical component of the system, study functions of each PLC control subsystem, as they are paper synchronization control system, heating temperature automation control system and remote operation panel control system.Introduce the S7 -200 series PLC, communication mode, principle for control system component selection, digital filtering, feed forward and feedback control methods; list the components configure for three control subsystems, study the incremental digital PID arithmetic and several reformative digital PID arithmetic suitable for PLC application; by employing real time data diagrams and figures, give out particular description of application of digital PI arithmetic with boundary invalidation & variant proportional parameter & variant integration time in paper synchronization control system, and common PI control arithmetic in heating temperature automation control system.更多还原