恒温电热水炉控制系统设计..doc

恒温电热水炉控制系统设计 摘 要 电热水锅炉是一种新型的机电一体化产品，是目前较为理想的环保、节能型供暖设备。由于电热水锅炉的温度、水位控制都具有非线性、大惯性、大滞后以及难以建立精确的数学模型的特点，因此给控制过程带来很大麻烦。在本设计中，寻求一种最佳的控制方案，以达到系统稳定、调节时间短且超调量小的性能指标。 本文先阐述了恒温电热水炉控制系统国内外研究现状，对可用的控制方案进行了说明。先对常规PID控制、模糊控制的理论基础进行了说明，然后分别设计控制器，根据被控对象的数学模型，利用Matlab的Simulink开发环境和模糊逻辑工具箱分别对温度、水位的PID控制系统和模糊控制系统进行仿真分析。结果表明模糊控制的效果更好，性能指标更为理想，因此模糊控制是一种较为理想的控制方案。在电热水锅炉控制系统对系统功能要求的基础上，设计了以AT89C51单片机为核心部件的硬件电路，实现了温度的采集与控制、水位的采集与控制、无水报警与保护等各种功能。在硬件电路设计的同时，也进行了相应的软件设计，系统软件设计采用了模块化结构，分模块进行设计。 关键词：温度，水位，模糊控制，仿真，单片机 CONTROL SYSTEM DESIGN OF THERMOSTAT ELECTRIC WATER HEATER ABSTRACT Electric hot water boiler is a kind of electromechanical product model, which is environmental friendly, energy-saving heating equipment of the ideal. Because the control of electric water boiler’s temperature, water level has the nonlinear, large inertia, large delay and it is difficult to establish accurate mathematical model, so to control the process have a lot of trouble. In this design, in order to achieve the performance index of system stability, control performance in short time and small overshoot , to seek an optimal control scheme is important. This paper first describes the present situation of the constant temperature control system of electric water heaters both at home and abroad ,then introduce some available control schemes. At first , the theoretical basis of conventional PID control and fuzzy control, then based on the mathematical model of the object, design the controller, using Matlab Simulink development environment and the fuzzy logic toolbox respectively on the temperature and water level in the PID control system and fuzzy control system simulation analysis. The results show that the performance of fuzzy control is better, so the fuzzy control is a kind of ideal control scheme. Based on the system function requirement of electric hot water boiler control system, designing the hardware circuit with AT89C51 single chip as the core components of the design, realizing th