基于PLC控制的空調冷卻塔循環(huán)水泵的變頻節(jié)能研究
發(fā)布時間：2018-07-18 12:36
【摘要】：本文是對惠亞電子科技(深圳)有限公司的中央空調冷卻塔系統(tǒng)進行節(jié)能的應用研究。在中央空調冷卻塔系統(tǒng)中，全壓運行的工作方式因結構簡單、初期投資少，而在各行各業(yè)中得到長期、廣泛的應用。但由于全壓運行方式的水泵輸出功率與負荷的波動無動態(tài)變化關系，因而存在嚴重浪費電能的問題，隨著國家節(jié)能政策的推進，以及企業(yè)營運成本削減需求的高漲，在中央空調冷卻塔系統(tǒng)中引入實時控制已成為必須的要求。 首先，針對熱負荷情況及空調設備的工作特點，在明確設備的工藝要求條件下，結合循環(huán)水泵變頻節(jié)電原理，分析現(xiàn)場數據后，預估出節(jié)能幅度。確定控制對象為冷卻水塔的出水溫度并提出了3種備選方案，經比較確定采用變頻分段自動控制方案（一級閉環(huán)反饋方案）。基于PLC控制的空調冷卻塔循環(huán)水泵變頻節(jié)能應用研宄具有一定的拓展性：國內各種各樣的變頻調速的應用匯編并不罕見，有的理論性較強，但多偏重仿真；有的則偏重應用效果而缺乏技術細節(jié)介紹。本文力求吸取前輩經驗精華，用于改造方案總體設計，并在改造設計前，進行系統(tǒng)失效模式與效果分析，，并制定相應的防范對策。 接著，結合主要部件的性能規(guī)格進行如下設計：（1)系統(tǒng)電路圖設計：主回路用變頻/工頻雙電源供電方式；變頻器用DC mA控制信號，提高抗干擾能力。（2) PLC程序設計：建立冷卻塔出水溫度（°C)、冷卻塔出水溫度經A/D轉換后的數字量（V)、水泵電動機運行頻率（Hz)三者的比例關系，使它們能等量轉換，實現(xiàn)控制、比較、顯示功能；用區(qū)間比較功能指令解決分段自動控制問題；用程序TO/FROM指令，結合專用模塊存儲器分配表，實現(xiàn)出水溫度值的A/D轉換和輸出頻率的D/A轉換;(3)觸摸屏人機畫面設計：監(jiān)控實時參數、建立累計運行時間檔案、設計人工指令如調節(jié)受控溫度區(qū)間和對應的水泵電動機運行頻率值、自動/手動方式選擇等。 最后,裝置用于實際驗證。2013年7月投入運行以來，8個月的運行表明：（1)系統(tǒng)無自激振蕩、無失控；沒有元件損壞。（2)通過電度表對改造前/后的電能用量比較可得：每小時平均用電量節(jié)省了31.11%。（3)通過示波器測量改造前/后變頻器輸入/輸出端電壓波形，可知新系統(tǒng)的諧波、噪聲在可接受水平。
[Abstract]:This paper studies the application of energy-saving in central air-conditioning cooling tower system of Huiya Electronic Technology (Shenzhen) Co., Ltd. In the central air conditioning cooling tower system, the operation mode of full pressure operation is widely used in various industries because of its simple structure and low initial investment. However, since the output power of pump in full pressure operation mode has no dynamic relation with the fluctuation of load, there is a serious problem of wasting electric energy. With the promotion of national energy conservation policy and the high demand for reducing the operating cost of enterprises, the output power of the pump has no dynamic relationship with the fluctuation of the load. It is necessary to introduce real-time control into the cooling tower system of central air-conditioning system. Firstly, according to the heat load and the working characteristics of air conditioning equipment, under the condition of clear equipment process requirement, combined with the principle of circulating water pump frequency conversion and electricity saving, the energy saving range is estimated after analyzing the field data. The effluent temperature of the cooling water tower is determined as the control object and three alternative schemes are put forward. The frequency conversion subsection automatic control scheme (one stage closed loop feedback scheme) is adopted by comparison. The research on the application of frequency conversion and energy saving of circulating water pump in air conditioning cooling tower based on PLC has certain expansibility: the application compilation of various frequency conversion speed regulation in our country is not rare, some theory is strong, but more emphasis is placed on simulation; Some emphasis on application results and lack of technical details. This paper tries to absorb the quintessence of the predecessor's experience and apply it to the overall design of the transformation scheme. Before the transformation design, the failure mode and effect of the system are analyzed, and the corresponding countermeasures are worked out. Then, according to the performance specifications of the main components, the following designs are carried out: (1) the circuit diagram of the system: the main circuit is supplied by frequency conversion / power frequency dual power supply mode, and the DC Ma control signal is used in the converter. (2) PLC program design: the proportional relationship of cooling tower effluent temperature (擄C), cooling tower effluent temperature (V) after A- / D conversion and pump motor operating frequency (Hz) is established, so that they can be converted in equal quantities to realize control and comparison. Display function; using interval comparison function instruction to solve segment automatic control problem; using program TO-FROM instruction, combined with special module memory allocation table, Ar / D conversion of effluent temperature and D / A conversion of output frequency; (3) human-computer screen design of touch screen: monitoring real-time parameters, establishing cumulative running time file, Design manual instructions such as adjusting the controlled temperature range and the corresponding operating frequency of pump motor, automatic / manual mode selection, etc. Finally, the device is used for practical verification. Since it was put into operation in July 2013, the 8-month operation shows that: (1) the system has no self-excited oscillation and no runaway; No component damage. (2) through the watt-hour meter before / after the power consumption comparison can be obtained: the average power consumption per hour saved 31.11. (3) through the oscilloscope to measure the input / output voltage waveform of the inverter before / after the transformation, we can know the harmonic of the new system, Noise is at acceptable levels.
【學位授予單位】：華南理工大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TB657.2
本文編號：2131922
[Abstract]:This paper studies the application of energy-saving in central air-conditioning cooling tower system of Huiya Electronic Technology (Shenzhen) Co., Ltd. In the central air conditioning cooling tower system, the operation mode of full pressure operation is widely used in various industries because of its simple structure and low initial investment. However, since the output power of pump in full pressure operation mode has no dynamic relation with the fluctuation of load, there is a serious problem of wasting electric energy. With the promotion of national energy conservation policy and the high demand for reducing the operating cost of enterprises, the output power of the pump has no dynamic relationship with the fluctuation of the load. It is necessary to introduce real-time control into the cooling tower system of central air-conditioning system. Firstly, according to the heat load and the working characteristics of air conditioning equipment, under the condition of clear equipment process requirement, combined with the principle of circulating water pump frequency conversion and electricity saving, the energy saving range is estimated after analyzing the field data. The effluent temperature of the cooling water tower is determined as the control object and three alternative schemes are put forward. The frequency conversion subsection automatic control scheme (one stage closed loop feedback scheme) is adopted by comparison. The research on the application of frequency conversion and energy saving of circulating water pump in air conditioning cooling tower based on PLC has certain expansibility: the application compilation of various frequency conversion speed regulation in our country is not rare, some theory is strong, but more emphasis is placed on simulation; Some emphasis on application results and lack of technical details. This paper tries to absorb the quintessence of the predecessor's experience and apply it to the overall design of the transformation scheme. Before the transformation design, the failure mode and effect of the system are analyzed, and the corresponding countermeasures are worked out. Then, according to the performance specifications of the main components, the following designs are carried out: (1) the circuit diagram of the system: the main circuit is supplied by frequency conversion / power frequency dual power supply mode, and the DC Ma control signal is used in the converter. (2) PLC program design: the proportional relationship of cooling tower effluent temperature (擄C), cooling tower effluent temperature (V) after A- / D conversion and pump motor operating frequency (Hz) is established, so that they can be converted in equal quantities to realize control and comparison. Display function; using interval comparison function instruction to solve segment automatic control problem; using program TO-FROM instruction, combined with special module memory allocation table, Ar / D conversion of effluent temperature and D / A conversion of output frequency; (3) human-computer screen design of touch screen: monitoring real-time parameters, establishing cumulative running time file, Design manual instructions such as adjusting the controlled temperature range and the corresponding operating frequency of pump motor, automatic / manual mode selection, etc. Finally, the device is used for practical verification. Since it was put into operation in July 2013, the 8-month operation shows that: (1) the system has no self-excited oscillation and no runaway; No component damage. (2) through the watt-hour meter before / after the power consumption comparison can be obtained: the average power consumption per hour saved 31.11. (3) through the oscilloscope to measure the input / output voltage waveform of the inverter before / after the transformation, we can know the harmonic of the new system, Noise is at acceptable levels.
【學位授予單位】：華南理工大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TB657.2
【參考文獻】
相關期刊論文 前1條
1 呂艷;;PLC、變頻器在中央空調冷卻水泵節(jié)能循環(huán)控制中的應用[J];自動化技術與應用;2010年08期
本文編號：2131922
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