本文選題：蒸發(fā)器 + 過(guò)熱度��； 參考：《沈陽(yáng)工業(yè)大學(xué)》2017年碩士論文

【摘要】：近年來(lái),中央空調(diào)成為人們工作生活中的必備家用電器之一,為人們提供舒適的環(huán)境以滿足人們對(duì)生活品質(zhì)的要求,但同時(shí)也發(fā)現(xiàn)空調(diào)對(duì)于電能的大量消耗的問(wèn)題。因此穩(wěn)定性與節(jié)能性能的好壞逐漸成為中央空調(diào)的設(shè)計(jì)研發(fā)者們研究的重點(diǎn)。而中央空調(diào)制冷循環(huán)系統(tǒng)中的蒸發(fā)器是制取冷量的關(guān)鍵部件,對(duì)于中央空調(diào)蒸發(fā)器出口過(guò)熱度的控制研究于空調(diào)系統(tǒng)的節(jié)能與穩(wěn)定性有重要的影響。本文主要以中央空調(diào)蒸發(fā)器的建模與蒸發(fā)器出口制冷劑過(guò)熱度的控制問(wèn)題進(jìn)行研究。首先,在分析中央空調(diào)蒸發(fā)器的工作原理后以蒸發(fā)器為研究對(duì)象,對(duì)蒸發(fā)器建立機(jī)理模型。將蒸發(fā)器按照制冷劑在管內(nèi)的物理狀態(tài)分為兩個(gè)區(qū)域(兩相區(qū)與過(guò)熱區(qū)),對(duì)每個(gè)區(qū)域先應(yīng)用一維簡(jiǎn)化的流體力學(xué)守恒微分方程,用萊布尼茲公式進(jìn)行積分,將方程聯(lián)立整理為五階的非線性系統(tǒng)模型。然后對(duì)模型在穩(wěn)定工作點(diǎn)進(jìn)行線性化處理,并轉(zhuǎn)化為標(biāo)準(zhǔn)的五階線性狀態(tài)空間模型�？紤]到在對(duì)被控對(duì)象進(jìn)行分析、以及線性化處理的過(guò)程中,使模型的參數(shù)產(chǎn)生一定的誤差,模型參數(shù)具有不確定性,則描述蒸發(fā)器的數(shù)學(xué)模型變?yōu)橐哉舭l(fā)器兩相區(qū)長(zhǎng)度、蒸發(fā)壓力、蒸發(fā)器出口制冷劑焓值、兩相區(qū)管壁溫度與過(guò)熱區(qū)管壁溫度為狀態(tài)變量的五階線性不確定狀態(tài)空間模型。其次,設(shè)計(jì)了基于改進(jìn)的線性二次最優(yōu)算法的魯棒輸出跟蹤控制策略。針對(duì)中央空調(diào)蒸發(fā)器出口過(guò)熱度控制的控制策略應(yīng)滿足蒸發(fā)器出口的實(shí)際過(guò)熱度能跟蹤到目標(biāo)過(guò)熱度的設(shè)定值,并且輸出跟蹤誤差逐漸收斂為零。此控制策略首先基于第三章建立的蒸發(fā)器五階數(shù)學(xué)模型構(gòu)建增廣狀態(tài)方程,然后應(yīng)用傳統(tǒng)的線性二次最優(yōu)算法,求出最優(yōu)控制率,最后在此基礎(chǔ)上引入調(diào)整因子,得到改進(jìn)后的最優(yōu)控制率。最后,驗(yàn)證基于改進(jìn)的線性二次最優(yōu)算法的魯棒輸出跟蹤控制策略針對(duì)中央空調(diào)蒸發(fā)器出口制冷劑過(guò)熱度控制的控制效果,并在MATLAB環(huán)境下進(jìn)行仿真分析。仿真結(jié)果表明,所設(shè)計(jì)的魯棒輸出跟蹤控制策略的有效性,且反應(yīng)速度快,能快速跟蹤目標(biāo)過(guò)熱度的設(shè)定值。
[Abstract]:In recent years, central air conditioning has become one of the necessary household appliances in people's work and life, providing people with comfortable environment to meet the requirements of people's quality of life, but at the same time, it also found that air conditioning consumes a lot of electric energy. Therefore, stability and energy-saving performance gradually become the focus of central air-conditioning design and research. The evaporator in the central air-conditioning refrigeration cycle system is the key component of the cooling capacity, which has an important impact on the energy saving and stability of the central air conditioning system for the research on the control of the outlet superheat degree of the central air-conditioning evaporator. In this paper, the modeling of central air conditioner evaporator and the control of refrigerant superheat at evaporator outlet are studied. Firstly, after analyzing the working principle of central air conditioning evaporator, the mechanism model of evaporator is established. The evaporator is divided into two regions according to the physical state of the refrigerant in the tube (two-phase region and superheated region). The one-dimensional simplified hydrodynamic conservation differential equation is applied to each region, and the Leibniz formula is used to integrate the evaporator. The equations are arranged into a fifth order nonlinear system model. Then the model is linearized at the stable working point and transformed into a standard five-order linear state space model. Considering that in the process of analyzing and linearizing the controlled object, the parameters of the model have some errors and the parameters of the model are uncertain, the mathematical model describing the evaporator is changed to the length of the evaporator two-phase zone. A five-order linear uncertain state space model with evaporation pressure, refrigerant enthalpy at the outlet of evaporator, wall temperature in two-phase region and tube wall temperature in superheated region is a five-order linear state space model. Secondly, a robust output tracking control strategy based on the improved linear quadratic optimal algorithm is designed. In view of the control strategy of superheat at the outlet of central air-conditioning evaporator, the actual superheat of evaporator outlet can be tracked to the set value of target superheat, and the output tracking error converges to zero gradually. The control strategy is based on the fifth order mathematical model of evaporator established in Chapter 3 to construct the augmented state equation. Then the optimal control rate is obtained by using the traditional linear quadratic optimal algorithm. Finally, the adjustment factor is introduced. The improved optimal control rate is obtained. Finally, the robust output tracking control strategy based on the improved linear quadratic optimal algorithm is verified for the control effect of refrigerant superheat control for the outlet refrigerant of central air-conditioning evaporator, and the simulation analysis is carried out in MATLAB environment. The simulation results show that the proposed robust output tracking control strategy is effective and fast, and can track the target superheat quickly.
【學(xué)位授予單位】：沈陽(yáng)工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TB657.2

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