电子仪器热输运系统模型及其设计方法研究
摘要
随着科技的日新月异,电子仪器的集成度越来越高,而硬件设计上每增加一个集成度,电子仪器所散发的热量也会相对增加。而电子仪器能否可靠工作,能否持久耐用很大程度上取决于装置和功率器件能否有效散热。这就使得电子设备和单个功率器件的热输运问题日益突出。本文就此做了深入的研究,目的就是希望能为电子仪器热输运问题找到一条合理有效的解决途径。
我们着力研究了热管、半导体制冷等制冷方法。并应用半导体制冷原理搭建了恒温控制平台。此平台主要包括电压基准、温度测量、减法器、PID控制、限幅、TEC驱动等六大组成部分。我们在实验中还应用了导热板、热沉等辅助设备。简单的说,工作原理就是通过温度传感器采集热负载(大功率晶体管)温度,经过反馈得到差值,再由PID处理,用PID处理过的输出信号控制TEC制冷(或加热),从而实现时时检测,时时控制。此外,我们还为此热输运系统建立了数学模型。
实验中我们对比了加温度控制平台和不加控制平台的效果。我们发现不加温度控制平台时热负载温度迅速上升,直至烧毁。加了温度控制平台后,温度很稳定,也就是说我们不是被动的给大功率晶体管降温,而是让大功率晶体管按照我们设置的温度去工作。这样一来我们对管子的各个参数就能有很好的把握。我们在实验中还测算了整个热输运系统的短期稳定度和长期稳定度,测算结果是,短期稳定度是0.02℃,长期稳定度是0.05℃。虽然实验结果达到了我们的要求,但我们也发现了系统的一些不足,在本文的最后我们提出了一些设想和展望,希望在日后的工作中能得以完善。
With the rapid development of electronic technology, the shrinking size of electronic equipment and gradually increase of the complexity and function,that lead to a dramatic increase in heat density, temperature increased rapidly. The high temperature was the most serious harm to most electronic components because it will lead to component failure even electronic equipment not normal work as a whole. Information show: more than±15℃temperature cycling change will be greatly reduced service life and reliability of electronic components. Temperature changes of more than±20℃, the failure rate of electronic components can be increased to 8.1 times. With the continuous improvement requirements for the test data and the experimental accuracy, the impact of the unfavorable factors such as high temperature are being attention. A lot of researchers at home and abroad are actively taking part in research of cooling, temperature control. In such an environment, we studied the heat transport model of electronic devices and hoped to solve the problem about cooling of the electronic equipment.
We first systematically studied the basic theory, so laid a solid theoretical basis for follow-up work. In the study of heat transport system design, we conducted thermoelectric simulation for power devices, and described in detail the selection principles of fans and radiators. In addition, we have thoroughly studied the some usual methods of electronic equipment heat transport.
Heat pipe technology is one of the heat transport methods applied usually now. Diathermanous capacity of heat pipes, in terms of weight and size, many times higher than the best heat transfer materials. Heat pipe can be individually designed to meet the requirements of the application. Heat pipe can also conduct heat long distance (a few feet) and keep small changes in temperature. Heat pipe and high voltage equipment can join directly because heat pipe may be made of insulating material completely. Moreover, it is not noise pollution and is environmental protection cooling device. Used in electronic equipment cooling, heat flow in the event of a change, and we hope the temperature remained stable. Heat Pipe control is a complex problem that have few practical solutions. What merits special mention is: the heat pipe is essentially a good thermal conductor, but its efficiency of cooling is obviously subject to the heat resistance between it and the heat producer. Heat Pipe has become the preferred method of heat dissipation of computer central processing unit (CPU), because of its compact size, no noise, high reliability.
In addition, the paper has also introduced a deep cooling refrigeration and gas swirl refrigeration and semiconductor refrigeration. We do an in-depth study of semiconductor refrigeration. Semiconductor refrigeration also is named thermoelectricity refrigeration. The material with characteristics of thermoelectric energy conversion is refrigeration when it links to direct current. This course is named thermoelectric refrigeration. It is primarily the application of Peltier effect in refrigeration technology. Semiconductor refrigeration device has simple structure, small size, and it is composed of thermopile and conducting wire. It has little vibration, low noise, no wear and long life, high dependability and favorable maintainability, because that it has no mechanical moving parts. Because it do not need refrigerant, the environment clean. Cooling rate of semiconductor refrigeration and cooling temperature may be regulated at will by changing the size of the current and voltage. Thermopile can be molded into any shape, and can run in any direction, even in states of weightlessness and overweight. It is reversible operation, including refrigeration and heating. This only need change the direction of current. It is less efficient when used in refrigeration, and when used in heating with high efficiency. So the overall assessment of their efficiency is still relatively high. Its amount of refrigeration may change at mW～kW and cooling difference in temperature can arrive at 20~150℃.
As one component of the experimental, constant temperature controller execution unit is semiconductors refrigerator. Constant temperature control circuit has six major components, which are voltage reference circuit, temperature measuring circuit, subtractor circuit, PID control circuit, and TEC driving circuit. This is a negative feedback control loop. It complete heating (or cooling) task by using temperature sensors detect changes in the temperature of thermal load then translating into electrical signals, using this as a negative feedback signal then the feedback signal and preset temperature signal in subtractor having to do subtraction operation margin, transmitting this margin to PID control circuit to deal with, this output signal controlling size and direction of TEC-driven current. Among them, voltage reference circuit is to provide a stable preset temperature for the entire permanent temperature controller. We are here to use the precision voltage reference (LM336), which having stable output voltage. It can overcome the effect of power source fluctuation. PID control circuit is a core part of entire thermostatic controller. PID control is a mature control theory, its control effect is satisfactory by adopting the combination of proportional, integral, differential. PID output signal may become very great as ring-opening. When the output signal joins directly to TEC driven circuit, the TEC will be damaged. Therefore, we joined the limiter circuit to prevent excessive drive currents. In this experiment, we chose a NTC with small volume, high temperature measurement accuracy as a temperature sensor. This temperature controller has digital display controller, which can shows the installed temperature and the actual temperature. In this paper, I have also set up a mathematical model for the electronic devices heat transport system and experimental results show that the reliability of the model.
In this paper, I calculated the minimum size of the radiator on the basis of experimental conditions and chosen a suitable radiator. I also designed the entire experimental framework based on the heat transport system. Then I installed experimental components and tested laboratory equipment and got the experimental data. By experimental data, we can find when no TEC controlling, the temperature of transistors rise rapidly. This will have an enormous impact on transistor parameters, with the loss of time, it may even be burnt transistor. With TEC control, the temperature has been brought under effective control. Which indicate the heat transport system may basically control the temperature of high power transistors. Further more, we can let high power transistors to work according to our requests rather than passively cooling. In this way, we will be able to hold the transistor parameter more accurate. Of course, the smaller of transistors’dissipation power, the better the TEC control. With analyzing the experimental data, we have found the brief stability of this system is about 0.02℃and the long term stability is about 0.05℃.In the experiments, I also found the defects of system, so I put forward my own ideas to perfect the system.
我们着力研究了热管、半导体制冷等制冷方法。并应用半导体制冷原理搭建了恒温控制平台。此平台主要包括电压基准、温度测量、减法器、PID控制、限幅、TEC驱动等六大组成部分。我们在实验中还应用了导热板、热沉等辅助设备。简单的说,工作原理就是通过温度传感器采集热负载(大功率晶体管)温度,经过反馈得到差值,再由PID处理,用PID处理过的输出信号控制TEC制冷(或加热),从而实现时时检测,时时控制。此外,我们还为此热输运系统建立了数学模型。
实验中我们对比了加温度控制平台和不加控制平台的效果。我们发现不加温度控制平台时热负载温度迅速上升,直至烧毁。加了温度控制平台后,温度很稳定,也就是说我们不是被动的给大功率晶体管降温,而是让大功率晶体管按照我们设置的温度去工作。这样一来我们对管子的各个参数就能有很好的把握。我们在实验中还测算了整个热输运系统的短期稳定度和长期稳定度,测算结果是,短期稳定度是0.02℃,长期稳定度是0.05℃。虽然实验结果达到了我们的要求,但我们也发现了系统的一些不足,在本文的最后我们提出了一些设想和展望,希望在日后的工作中能得以完善。
With the rapid development of electronic technology, the shrinking size of electronic equipment and gradually increase of the complexity and function,that lead to a dramatic increase in heat density, temperature increased rapidly. The high temperature was the most serious harm to most electronic components because it will lead to component failure even electronic equipment not normal work as a whole. Information show: more than±15℃temperature cycling change will be greatly reduced service life and reliability of electronic components. Temperature changes of more than±20℃, the failure rate of electronic components can be increased to 8.1 times. With the continuous improvement requirements for the test data and the experimental accuracy, the impact of the unfavorable factors such as high temperature are being attention. A lot of researchers at home and abroad are actively taking part in research of cooling, temperature control. In such an environment, we studied the heat transport model of electronic devices and hoped to solve the problem about cooling of the electronic equipment.
We first systematically studied the basic theory, so laid a solid theoretical basis for follow-up work. In the study of heat transport system design, we conducted thermoelectric simulation for power devices, and described in detail the selection principles of fans and radiators. In addition, we have thoroughly studied the some usual methods of electronic equipment heat transport.
Heat pipe technology is one of the heat transport methods applied usually now. Diathermanous capacity of heat pipes, in terms of weight and size, many times higher than the best heat transfer materials. Heat pipe can be individually designed to meet the requirements of the application. Heat pipe can also conduct heat long distance (a few feet) and keep small changes in temperature. Heat pipe and high voltage equipment can join directly because heat pipe may be made of insulating material completely. Moreover, it is not noise pollution and is environmental protection cooling device. Used in electronic equipment cooling, heat flow in the event of a change, and we hope the temperature remained stable. Heat Pipe control is a complex problem that have few practical solutions. What merits special mention is: the heat pipe is essentially a good thermal conductor, but its efficiency of cooling is obviously subject to the heat resistance between it and the heat producer. Heat Pipe has become the preferred method of heat dissipation of computer central processing unit (CPU), because of its compact size, no noise, high reliability.
In addition, the paper has also introduced a deep cooling refrigeration and gas swirl refrigeration and semiconductor refrigeration. We do an in-depth study of semiconductor refrigeration. Semiconductor refrigeration also is named thermoelectricity refrigeration. The material with characteristics of thermoelectric energy conversion is refrigeration when it links to direct current. This course is named thermoelectric refrigeration. It is primarily the application of Peltier effect in refrigeration technology. Semiconductor refrigeration device has simple structure, small size, and it is composed of thermopile and conducting wire. It has little vibration, low noise, no wear and long life, high dependability and favorable maintainability, because that it has no mechanical moving parts. Because it do not need refrigerant, the environment clean. Cooling rate of semiconductor refrigeration and cooling temperature may be regulated at will by changing the size of the current and voltage. Thermopile can be molded into any shape, and can run in any direction, even in states of weightlessness and overweight. It is reversible operation, including refrigeration and heating. This only need change the direction of current. It is less efficient when used in refrigeration, and when used in heating with high efficiency. So the overall assessment of their efficiency is still relatively high. Its amount of refrigeration may change at mW～kW and cooling difference in temperature can arrive at 20~150℃.
As one component of the experimental, constant temperature controller execution unit is semiconductors refrigerator. Constant temperature control circuit has six major components, which are voltage reference circuit, temperature measuring circuit, subtractor circuit, PID control circuit, and TEC driving circuit. This is a negative feedback control loop. It complete heating (or cooling) task by using temperature sensors detect changes in the temperature of thermal load then translating into electrical signals, using this as a negative feedback signal then the feedback signal and preset temperature signal in subtractor having to do subtraction operation margin, transmitting this margin to PID control circuit to deal with, this output signal controlling size and direction of TEC-driven current. Among them, voltage reference circuit is to provide a stable preset temperature for the entire permanent temperature controller. We are here to use the precision voltage reference (LM336), which having stable output voltage. It can overcome the effect of power source fluctuation. PID control circuit is a core part of entire thermostatic controller. PID control is a mature control theory, its control effect is satisfactory by adopting the combination of proportional, integral, differential. PID output signal may become very great as ring-opening. When the output signal joins directly to TEC driven circuit, the TEC will be damaged. Therefore, we joined the limiter circuit to prevent excessive drive currents. In this experiment, we chose a NTC with small volume, high temperature measurement accuracy as a temperature sensor. This temperature controller has digital display controller, which can shows the installed temperature and the actual temperature. In this paper, I have also set up a mathematical model for the electronic devices heat transport system and experimental results show that the reliability of the model.
In this paper, I calculated the minimum size of the radiator on the basis of experimental conditions and chosen a suitable radiator. I also designed the entire experimental framework based on the heat transport system. Then I installed experimental components and tested laboratory equipment and got the experimental data. By experimental data, we can find when no TEC controlling, the temperature of transistors rise rapidly. This will have an enormous impact on transistor parameters, with the loss of time, it may even be burnt transistor. With TEC control, the temperature has been brought under effective control. Which indicate the heat transport system may basically control the temperature of high power transistors. Further more, we can let high power transistors to work according to our requests rather than passively cooling. In this way, we will be able to hold the transistor parameter more accurate. Of course, the smaller of transistors’dissipation power, the better the TEC control. With analyzing the experimental data, we have found the brief stability of this system is about 0.02℃and the long term stability is about 0.05℃.In the experiments, I also found the defects of system, so I put forward my own ideas to perfect the system.
引文
[1] 丁连芬.电子设备可靠性热设计手册.电子工业出版社,1989:1~4,406~464.
[2] [美]D.S.斯坦伯格著,傅军译.电子设备冷却技术.航空工业出版社,1989:422~435.
[3] 清华大学电子学教研组编,童诗白主编.模拟电子技术基础.人民教育出版社,1981:58~61.
[4] 广西大学电气工程学院学生创作实验室.开关电源.2006:1~10.
[5] .叶家金.现代电力电子器件-大功率晶体管的原理和应用.中国铁道出版社,1992:13~14.
[6] 岳丹婷.工程热力学和传热学.大连海事大学出版社,2002:176~178.
[7] 钱滨江,伍贻文,常家芳,丁一鸣.简明传热手册.高等教育出版社,1983:1~6,147~152,202~216,341~344.
[8] 李庆友,王文,周根明.电子元器件散热方法研究.电子器件,2005,28(4):937~940.
[9] 齐永强,何雅玲,张伟,郭进军.电子设备热设计的初步研究.现代电子技术,2003,1(144):73~76.
[10] 叶大均.机械工程师手册.加工和流体力学,1989:35~37,60~65.
[11] 卓宁,孙家庆主编.工程对流换热.上海机械学院,机械工业出版社,1982(1):1~7.
[12] 葛新法.电子设备冷却风扇的选择.声学与电子工程,2004,3(75):51~53.
[13] 王健石主编.半导体器件散热图册.中国标准出版社,1995:1~6.
[14] 谢德仁.电子设备热设计.东南大学出版社,1989:95~104.
[15] 郑贤德.制冷原理与装置.机械工业出版社,2000:89~116.
[16] 靳明聪,陈远国.热管及热管换热器.重庆大学出版社,1986:1~6.
[17] 杨建军.计算机芯片热管散热技术分析.农业装备技术,2006,32(4):25~27.
[18] 姚寿广,马哲树,罗林,陈如冰.电子电器设备中高效热管散热技术的研究现状及发展.华东船舶工业学院学报(自然科学版),2003,17(4):9~11.
[19] 白敏丽,喜娜,孙志君,李河,杨洪武.用于 CPU 冷却的集成热管散热器.高技术通讯,2006,16(7):713~717.
[20] 吴红刚,王文,李庆友.一种芯片散热型热管的强化传热研究.科学技术与工程,2006,6(11):1474~1485.
[21] 郎逵,乔中复.热管技术与应用.辽宁科学技术出版社,1984:8~11, 27~35.
[22] 徐德胜.半导体制冷与应用技术.上海交通大学出版社,1992:1~10.
[23] 徐扬禾.制冷系统及其原理.航空工业出版社,1993:76~87.
[24] 周兴华.半导体制冷技术及应用.电子世界,2000(9):52.
[25] 重庆大学热管科研组,中国科学技术情报研究所重庆分所.热管基础及其应用.科学技术文献出版社重庆分社,1977:106~113.
[26] 庄骏,张红.热管技术及其工程应用.化学工业出版社,2000:31~64.
[27] 重庆大学热管科研组.热管研究与应用.重庆大学科技情报室,1974:108~111.
[28] Flavio Dobran etal 著,王礼建主译.热管技术的应用与发展.广西师范大学出版社,1991:211~215.
[29] 王远.模拟电子技术.北京理工大学出版社,1991:53~83.
[30] 张娜.半导体激光器恒温控制理论与应用.吉林大学学报(理学版),2002,40(3):284-287.
[31] 陶永华.新型 PID 控制及其应用.机械工业出版社,1998:118~119.
[32] 刘金琨.先进 PID 控制及其 MATLAB 仿真.电子工业出版社,2003:67~69.
[2] [美]D.S.斯坦伯格著,傅军译.电子设备冷却技术.航空工业出版社,1989:422~435.
[3] 清华大学电子学教研组编,童诗白主编.模拟电子技术基础.人民教育出版社,1981:58~61.
[4] 广西大学电气工程学院学生创作实验室.开关电源.2006:1~10.
[5] .叶家金.现代电力电子器件-大功率晶体管的原理和应用.中国铁道出版社,1992:13~14.
[6] 岳丹婷.工程热力学和传热学.大连海事大学出版社,2002:176~178.
[7] 钱滨江,伍贻文,常家芳,丁一鸣.简明传热手册.高等教育出版社,1983:1~6,147~152,202~216,341~344.
[8] 李庆友,王文,周根明.电子元器件散热方法研究.电子器件,2005,28(4):937~940.
[9] 齐永强,何雅玲,张伟,郭进军.电子设备热设计的初步研究.现代电子技术,2003,1(144):73~76.
[10] 叶大均.机械工程师手册.加工和流体力学,1989:35~37,60~65.
[11] 卓宁,孙家庆主编.工程对流换热.上海机械学院,机械工业出版社,1982(1):1~7.
[12] 葛新法.电子设备冷却风扇的选择.声学与电子工程,2004,3(75):51~53.
[13] 王健石主编.半导体器件散热图册.中国标准出版社,1995:1~6.
[14] 谢德仁.电子设备热设计.东南大学出版社,1989:95~104.
[15] 郑贤德.制冷原理与装置.机械工业出版社,2000:89~116.
[16] 靳明聪,陈远国.热管及热管换热器.重庆大学出版社,1986:1~6.
[17] 杨建军.计算机芯片热管散热技术分析.农业装备技术,2006,32(4):25~27.
[18] 姚寿广,马哲树,罗林,陈如冰.电子电器设备中高效热管散热技术的研究现状及发展.华东船舶工业学院学报(自然科学版),2003,17(4):9~11.
[19] 白敏丽,喜娜,孙志君,李河,杨洪武.用于 CPU 冷却的集成热管散热器.高技术通讯,2006,16(7):713~717.
[20] 吴红刚,王文,李庆友.一种芯片散热型热管的强化传热研究.科学技术与工程,2006,6(11):1474~1485.
[21] 郎逵,乔中复.热管技术与应用.辽宁科学技术出版社,1984:8~11, 27~35.
[22] 徐德胜.半导体制冷与应用技术.上海交通大学出版社,1992:1~10.
[23] 徐扬禾.制冷系统及其原理.航空工业出版社,1993:76~87.
[24] 周兴华.半导体制冷技术及应用.电子世界,2000(9):52.
[25] 重庆大学热管科研组,中国科学技术情报研究所重庆分所.热管基础及其应用.科学技术文献出版社重庆分社,1977:106~113.
[26] 庄骏,张红.热管技术及其工程应用.化学工业出版社,2000:31~64.
[27] 重庆大学热管科研组.热管研究与应用.重庆大学科技情报室,1974:108~111.
[28] Flavio Dobran etal 著,王礼建主译.热管技术的应用与发展.广西师范大学出版社,1991:211~215.
[29] 王远.模拟电子技术.北京理工大学出版社,1991:53~83.
[30] 张娜.半导体激光器恒温控制理论与应用.吉林大学学报(理学版),2002,40(3):284-287.
[31] 陶永华.新型 PID 控制及其应用.机械工业出版社,1998:118~119.
[32] 刘金琨.先进 PID 控制及其 MATLAB 仿真.电子工业出版社,2003:67~69.