【作者】 隋志蔚；

【导师】 杨前明；

【作者基本信息】 山东科技大学 ， 机械电子工程， 2008， 硕士

【摘要】 直膨式太阳能辅助热泵系统是在传统的空气源热泵基础上,将太阳能热利用技术与其有机结合,旨在最大限度地获得空气中低品位热能与太阳能,是一种集热泵空调与热泵热水器于一体的多功能复合装置。近年来“节能环保、降耗减排”一直受到国家宏观政策的鼓励与国家“十五”、“十一五”科技计划项目的支持。因此直膨式太阳能辅助热泵系统的研制具有显著的经济与社会效益。直膨式太阳能辅助热泵系统由于将太阳能集热器与室外换热器并联,系统热力循环追求空调系统最佳运行工况品质是控制策略的第一考虑因素;另一方面由于系统中设计了蓄热水箱,用以最大限度地储存热能,从而用来弥补太阳能光照不足与长时间低温天气低品位热源的不足。由于系统结构及其控制目标的改变,显然常规热泵控制策略与方法不能照搬套用。太阳能辅助热泵复合系统与常规热泵空调系统相比,既有其共性的一面,更有其特别之处。研究直膨式太阳能热泵复合热泵系统控制策略与控制方法是该项目技术趋于完善、走向成熟的关键。这是近年来太阳能热利用领域的热点话题,也是该技术领域研究的焦点之一。山东科技大学先进热泵技术实验室于2005年11月研究开发了一套小型太阳能辅助热泵多功能复合机系统(DX-SAHPM)实验样机,随后的两年时间内,课题组不断深入研究与完善,取得了新的研究进展。本课题在此背景基础上,针对直膨式太阳能热泵系统中压缩机变频技术、电子膨胀阀控制技术及其太阳能热泵系统工作性能进行了系统研究。探讨了直膨式太阳能热泵系统采用压缩机变频技术,力求在最短时间内机组产生的负荷与建筑物室内所需负荷相匹配的控制策略与方法;采用电子膨胀阀对系统工质流量进行数字调节,使其输出工质流量最佳限度满足蒸发器热负荷需求:本文以理论分析、系统仿真相结合的方法,研究压缩机变频系统和电子膨胀阀节流系统在供热工况下的特性,采用稳态集中参数法,分别建立了压缩机与电子膨胀阀控制系统数学模型,根据各自控制目标,提出了变频压缩机和电子膨胀阀PID控制策略,并进行了计算机仿真分析。针对PID控制参数的整定,文中分别用Matlab对VFC控制系统和EEV控制系统的闭环时域特性进行仿真,通过时域特性分析,确定PID调节器中K_p、T_i、T_d三个参数,仿真结果显示采用PID控制后系统的控制特性明显改善。本文以准确、可靠检测系统热物理参数为原则,针对变频压缩机的转速与室内负荷匹配、电子膨胀阀的开度与蒸发器过热度匹配为控制目标,提出了以PLC为微处理核心、人机界面作为实时监控的控制方案。介绍了VFC-EEV实验系统的控制原理、给出了VFC和EEV控制系统的软硬件设计方法。更多还原

【Abstract】 Direct-expansion solar assisted heat pump system is to combine organically solar heat utilization technology with the conventional air source heat pump to furthest absorb solar heat outside low quality heat, which is a new type of green equipment with the combination of heat pump air-condition and heat pump water heater. These years, ’energy-saving, environmental protection protection, reducing consumption’ have been pay more attention to our country and have been supported by the Tenth Fine-Year Plan and 11th Five-Year Plan. So the development of direct-expansion solar assisted heat pump system has prominent economic and society benefit.As solar collector and outside evaporator are fixed in parallel in direct-expansion solar assisted heat pump system, the system thermodynamic cycle air-conditioning system to pursue the best operating conditions quality is the first consideration of control strategy. On the other hand, water tank is designed to maximum store heat energy in the system, so as to make up the lack of light time and shortage of long time low-grade heat source. Due to the change of system structure and control objective, obviously conventional heat pump control strategy and method can not be copied. Compared with conventional heat pump system, direct-expansion solar assisted heat pump system has common character and its peculiarities. The sdudy of control strategy and method in direct-expansion solar assisted heat pump is the key that this technology goes to perfect. This is hot topic of solar thermal use area in recent years the, the technology is the focus of research in the field.Advanced heat pump technology lab of Shandong University of Science and Technology exploited a suit of minitype direct-expansion solar assisted heat pump multi-function machine in November 2005. In the succedent two years, the subject group have done a lot of work and gained new research progress. This topic researches compressor’s variable frequency technology, EEV’s control technology and working performance of direct-expansion solar assisted heat pump. In order to realize optimum working character, VFC is adopted to realize dynamic matching between variable-frequency compressor’s rotate speed and room heat loading; EEV is adopted to realize realize dynamic matching between refrigeration flux and evaporator load.This paper researches compressor’s variable-frequency system and EEV’s throttle system used theory analyse and system simulation, sets up VFC and EEV’s mathematical model used steady-state centralized parametric method, proposes VFC and EEV’s PID control tactic and simulation arithmetic. Aimed at setting of PID control parameters, this paper simulates closed-loop time-domain characteristic of VFC and EEV’s control system. We confirm K_p, T_i, T_d of PID adjustor using time-domain characteristic analyse. Simulation results show that system’s control characteristic improves prominently adopting PID control.Basing on credible and accurate thermal parameters, aiming at room heat loading and evaporator’s superheat degree, this paper brings forward control project which used PLC as microprocessor, touched screen as real-time monitor. It introduces VFC-EEV experimental system’s control principle and presents software and hardware design of VFC-EEV control system.This subject research gets hold of the science and technology plan item of Qingdao, 2007. Item number is 07-2-2-22-jch.更多还原