Present situation and development of electrical and electronic technology
Electrical and electronic technology is not only the basic discipline of electrical engineering and its related disciplines, but also the growing point of marginal and interdisciplinary disciplines. Based on the reality and development needs of China's power industry, this paper briefly introduces the basic theory of power electronics technology, the application of live equipment and the new technologies emerging in the field of power electronics technology.
Electrical and electronic technology; Electrical equipment; Current situation; develop
"Electrical and Electronic Technology" is a professional basic course of electrical specialty in NCO Vocational and Technical School. Electrical technology and electronic technology have developed very rapidly and are widely used. All new modern science and technology are closely related to electricity. As a teacher engaged in this kind of teaching, it is necessary to conduct in-depth research on the present situation and development of this technology.
I. Overview of electrical and electronic technologies
Basic theory of electrical technology: electrical technology includes various means and activities involved in the whole process of generation, transmission, control and application of electromagnetic energy and information. As a technology, its contents include: circuit and magnetic circuit theory, electromagnetic measurement, motor and relay contact control, safe electricity use, analog electronic circuit, digital circuit, automatic control system and so on.
Basic theory of electronic technology: The basic theory of electronic technology belongs to this sub-discipline: electronic circuit and network analysis, microwave, antenna, radio wave propagation, measurement, power supply, display technology, signal processing, information theory, automatic control principle, reliability theory and so on. They are all kinds of technical means or basic theories needed to form functional electronic systems.
Since 1950s, a series of emerging scientific and technological theories such as computer technology, electronic technology and engineering cybernetics have developed vigorously. The knowledge structure between basic science, applied science and technological development has become closer, and various disciplines and specialties have penetrated and crossed each other, which has made science and technology and social production form a huge and complex whole that is deeply divided and highly integrated, and has also promoted the development of electrical theory. New progress has been made in solving three-dimensional physical fields of complex structures, including electrostatic fields and electromagnetic fields. The method of moments, variational principle, function space and so on all introduce electrician theory. Based on the concept of equivalent model, a virtual magnetic charge and magnetic current model is developed, various dynamic potentials and different gauge choices are studied, and a generalized energy theorem is proposed. Due to the combination of system and component, the connotation of component has been expanded, including logic gate, controllable source, gyrator and large-scale integrated block. The development of various engineering systems has formed the same network theoretical basis, which makes network expansion a general theoretical method to study specific spatial structure and dynamics. Will generalized network theory? Field? With what? Road? Together, new frontier theoretical fields have emerged, such as network simulation of physical field theory, network method of radiation field, network diagram of plasma and so on. By referring to the research results of system theory, the overall performance and behavior of the system are combined with the system structure, parameters and local physical quantities, which further enriches the content of network problems. In the long years of human history, the technological revolution is a powerful driving force. Today, new technologies characterized by electronic and computer technologies are expanding human intelligence. It is the technical application of electromagnetic laws in the fields of energy, information and control that depicts the blueprint of modern society and forms the mainstream of the new technological revolution. It impacts every corner of social production and life, which not only greatly improves social productivity and creates rich material wealth, but also changes people's lifestyle, social behavior, education and training, and way of thinking, and promotes social spiritual civilization. Electricians are merging with modern science and technology and continue to play the role of pillars of society.
Second, the current situation and development of electrical equipment
(1) electrical equipment? Healthy? There are differences in conditions
First of all, the innate conditions of equipment are different, and the technical conditions of imported equipment and domestic equipment are different; The same domestic equipment, different manufacturers have different product quality because of different technology and management levels; Even the same manufacturer, due to differences in technology and management, its product quality is different; The quality of products in different periods and batches will be different. Therefore, it should be admitted that the initial state of equipment put into operation is very different.
Secondly, the use environment of the equipment is different, and different environments will have different effects on the operation of the equipment. There are mainly two kinds of environments: first, the external natural environment in which the equipment is located is different, especially the power supply equipment, most of which are exposed to the outdoor natural environment, and the influence on the equipment is quite different due to factors such as temperature, humidity, pollution, ultraviolet rays and sunlight; Secondly, due to the different positions of equipment in the power system, the operating voltage, short-circuit current and thermal stability time of the system are also different, especially the short-circuit capacity when the system fails.
(B) Electrical equipment maintenance system: disadvantages of regular maintenance
Because the initial state of electrical equipment is very different from the running state of field equipment, that is, the field equipment's? Healthy? Conditions vary widely, and the regular maintenance system almost ignores these differences, and adopts a unified and one-size-fits-all regular maintenance method, which is mainly manifested in the maintenance results, either excessive maintenance or insufficient maintenance. The actual situation of the project is mostly over-maintenance, which often happens? Cure a minor illness? 、? Disease-free treatment? The phenomenon of blind maintenance, as the result of excessive maintenance, will inevitably lead to the following disadvantages: some equipment in good condition will fail or have potential failures due to blind maintenance, and maintenance will not restore the original reliability of equipment, but will increase the hidden dangers and failure rate of equipment. At present, regular maintenance is the main reason for the outage of electrical equipment, which often accounts for more than 60% of the total outage time.
In the future research direction, experts are concerned about the possibility of condition-based maintenance completely replacing regular maintenance.
(3) electrical equipment condition detection technology
Condition monitoring of electrical equipment provides a basis for fault diagnosis and performance evaluation of equipment. Therefore, it is necessary to monitor their operation status and know and master the equipment status in time to ensure the safe and stable operation of the whole power system. Condition monitoring refers to evaluating the running state of equipment through various measurement, detection and analysis means, combined with the history and present situation of system operation, so as to understand and master the running state of equipment, display and record the equipment state, handle abnormal situations, and provide basic data for fault analysis, diagnosis and performance evaluation of equipment.
In recent years, many foreign advanced technologies, equipment and management have been introduced into China's electrical equipment manufacturing, especially after 2 1 century, the use of new technologies and materials has greatly improved the equipment level of electrical systems. Therefore, the maintenance system and methods of electrical equipment should be adjusted appropriately according to the situation, so as to improve the stability of electrical equipment, reduce production costs and create more economic benefits for enterprises.
Third, the present situation and development of electronic equipment
In 20 10, the global sales of semiconductor manufacturing equipment reached $39.54 billion, returning to the highest level in history. The equipment expenditure in all regions showed a double-digit or even triple-digit percentage growth, with the fastest growth in Chinese mainland and South Korea. In 20 10, the market size of semiconductor equipment in China will be 2.24 billion dollars, and it is expected to be 2.64 billion dollars in 2010. According to this growth rate, by 20 15 years, the semiconductor equipment market in China will reach 30 billion yuan. In 20 10, the global sales of photovoltaic production equipment increased by 40% over the previous year, reaching 104 billion US dollars, and it is expected to reach 124 billion US dollars in 2010, with a year-on-year increase of 24%. In terms of regional market, Chinese mainland accounted for 565,438+0% of the global market in 2065,438+00, and it is expected that this proportion will remain high in the next five years. According to this, it can be judged that by 20 15 years, China photovoltaic equipment will continue to maintain a huge market space. The production equipment of new electronic components, such as lithium-ion power batteries for new energy vehicles, high-performance permanent magnet synchronous motors and metallized ultra-thin film power capacitors, will become the new growth point of China electronic special equipment market. The intersection of multiple disciplines has opened up a new development space for electronic instruments. The development of Internet of Things technology and triple play puts forward new test requirements for electronic instruments. It is expected that electronic instruments, environmental protection testing instruments and medical electronic instruments in the above fields will face great development.
Fourth, the new electrical technology
We are already preparing to enter the 2 1 century. 2 1 century, mankind is looking forward to entering a new era of sustained and coordinated development, and China will stand in the world with a new attitude worthy of our great nation. In the whole process, the progress and development of science and technology is of great significance. From the perspective of energy development, China is unlikely to reverse the energy structure dominated by coal in the first half of the year, so we should vigorously improve the utilization efficiency of coal, especially the efficiency of coal-fired power generation. At the same time, we should vigorously promote the application and development of nuclear energy and renewable energy, so as to make them mature faster in technology and economy. Only in this way can we quickly change the energy structure dominated by fossil energy and embark on the road of sustained, coordinated and stable development of energy, environment and ecology. In terms of transportation, realizing high speed will be the main development direction, and all kinds of high-speed transportation must be based on the development of electric propulsion system. The development of new electrical technology will play an important role in the development of energy, transportation and other industries. Some progress in the second half of the 20th century laid a good foundation for this. With the development of new principles, new technologies and new materials, some emerging fields will appear. This paper briefly looks forward to some significant visible progress, including controlled nuclear fusion, magnetic fluid power generation, solar and wind power generation, magnetic levitation train, magnetic fluid ship propulsion and superconducting electrician.
(1) controlled nuclear fusion
The realization of controlled nuclear fusion will provide almost inexhaustible clean energy for human beings and fundamentally solve the sustainable and coordinated development of human energy, environment and ecology. In the second half of the 20th century, great efforts were made in the large tokamak magnetic confinement fusion device? Ignition? Conditions, confirmed the scientific reality of the fusion reactor, the international joint design and development of the fusion test reactor is under way, and it is expected that the test reactor can be built and operated in the next century. Then, after two stages of demonstration reactor and commercial reactor, it is expected that the first commercial substation will be built and industrialized in the 1940s and 1950s. Different from the history that fission reactors mainly rely on the combination of nuclear engineering technology and thermal technology, the development of fusion reactors mainly depends on the combination of nuclear engineering technology and new electrical technology. Here, technologies such as large volume and strong magnetic field, high energy, pulse power supply technology, auxiliary heating technology and plasma control technology should be raised to a new level. In addition, it is necessary to explore the possibility of using charged particles produced by fusion to generate electricity directly. The realization of multi-substation will also lead to the formation of some emerging electrician industries.
(2) Magnetic fluid power generation
Magnetohydrodynamic power generation is a new type of power generation, which directly converts thermal energy into electrical energy through the interaction between high-temperature conductive gas and magnetic field. Because its initial temperature can be as high as 3000K, combined with the existing gas and steam power generation, it is expected to improve the thermoelectric conversion efficiency of coal-fired power plants to more than 50%, which has great advantages of high efficiency, low pollution and less water consumption. After 30 years of continuous efforts, magnetic fluid power generation has reached the highest power generation level of tens of thousands of kilowatts and hundreds of hours since the successful principle experiment in the early 1960s. After several stages of development, such as experimental power station, demonstration power station and commercial power station, it is expected to be commercialized in 265438+1920s and 1930s. The development process of MHD power generation shows that the difficulties encountered are much greater than originally thought, especially the long-term and reliable coal-fired power generation. There is a need to vigorously develop new technologies in many aspects, such as electrician, thermal engineering, materials and chemical engineering. In electrical engineering, we should solve a series of key technical problems such as power station system, power generation channel, superconducting magnet, power regulation and inverter, and make great progress on the existing basis. China is a country with coal as the main resource and rapid power development. The commercialization of MHD coal-fired power generation is of great significance.
(3) Solar and wind power generation
Solar energy and wind energy are the most important renewable energy sources, which are widely distributed, have equal opportunities, can be obtained free of charge and are ultimately reliable. In recent years, the technology of solar energy and wind power generation has made gratifying progress, and the construction investment and electric energy cost have been greatly reduced. Hundreds of thousands of kilowatts of solar thermal power plants and millions of kilowatts of large wind power plants have been connected to the grid for many years, and thousands of kilowatts of photovoltaic power plants have been demonstrated, which makes more and more people believe that in 2 1 century, solar energy and wind power generation can occupy a certain share in the whole power production. Therefore, it is necessary to continue to work hard to improve efficiency, reduce construction costs and expenses, foster the development of corresponding industries, and solve related technical problems in grid-connected operation.
(4) Maglev train
A history of traffic development in human society, in a sense, can be said to be a history of technological development with the main goal of improving traffic speed. The electrification of railways in the second half of the 20th century increased the operating speed of traditional wheel-rail railways to more than 200 kilometers per hour. In order to further improve the speed, the maglev train was developed. It is a new type of wheelless high-speed ground vehicle driven by magnetic levitation and linear motor. It has a series of advantages such as high speed, large passenger capacity, little environmental impact, low energy consumption, cheap maintenance, safe and stable operation, no derailment danger, strong climbing ability and so on. After decades of continuous efforts, the maglev train has reached the speed of 500 km/h, which is in the actual testing stage, and the maglev train in China was put into trial operation several years ago. Pay close attention to the research and development of high-speed maglev train in the future, and realize it technically? Catch up? Strategy is particularly important. The realization of maglev train should solve a series of high-tech key problems such as maglev, linear motor drive, vehicle design and development, track facilities, power supply system, train detection and control, and push the new electrician technology to a new peak. There are two technical schemes for high-speed maglev train: normal guidance and superconductivity. The advantages of using superconductivity are large suspension air gap, simple track structure, low cost and light car body. With the development and application of HTS, it will have greater advantages.
(5) magnetic fluid ship propulsion
Magnetic fluid ship propulsion is a new technology. It uses Lorentz force generated by the interaction between strong magnetic field and water flow in seawater to make seawater jet backward, and relies on its reaction force to push the ship forward. Because the propeller is not used, it has the advantages of silence and high speed, which will cause a major revolution in ship propulsion technology. With the smooth realization of superconducting strong magnetic field, serious research and development work began in the 1960s. Japan's manned test ship in the early 1990s? Yamato one? The success of sea trial shows the reality of its realization. After a decade or two of continuous phased efforts, it can be expected to be practical in the first half of 2 1 century.
(6) Superconducting electrician
The development and application of practical superconducting wire and superconducting magnet technology and the realization of initial industrialization are undoubtedly the great achievements of new electrical technology in the second half of the 20th century. 2/KLOC-0 In the first half of the century, the commercialization of MHD propulsion ship, whether it is substation, MHD power generation or maglev train, will promote the superconducting electrician to continue to develop by leaps and bounds and become an important electrician industry. At the same time, it can be expected that with the practical development of high critical temperature superconductors, superconducting power transmission and superconducting flywheel energy storage will be applied in practice. The development of power frequency superconducting technology will put superconducting current limiter, superconducting transformer and superconducting generator into operation, demonstrate and popularize high-energy superconducting energy storage, and superconducting power technology will become an important pillar of power development. If a practical superconductor with a critical temperature of room temperature appeared at that time, the whole appearance would be greatly changed. V. New electronic technologies
(A) plastic solar cell technology
With the increasing shortage of energy in the world today, many countries are committed to the research of solar energy development and utilization technology. Some facilities powered by solar cells can already be seen on the streets of some cities. After decades of research and development, these solar cells made of silicon are still expensive to manufacture, difficult to install, and have low photoelectric conversion efficiency, which is only about 12% to 15% (the best photoelectric conversion efficiency of monocrystalline silicon in the world is about 30% now), and the cost of generating 1 kwh electricity is about 22 cents, far exceeding that of coal-fired power plants.
The good news is that the next generation of solar cells may eventually make solar power generation competitive. The new solar cell is a solar power generation film made by embedding photovoltaic cells on the surface of plastic film. This kind of solar power generation film has the advantages of low price, high conversion efficiency and wide application.
Some big companies began to pay attention to new solar cell technology. A new technology developed by Siemens is to fuse nano-carbon 60 molecules with conductive polymers to make plastic solar cells; General Electric Company of the United States uses organic light-emitting diodes as light-absorbing materials to manufacture plastic solar cells. Using plastic solar cells can actually make many materials have power generation capacity. For example, a plastic solar cell can be embedded in the box wall of a notebook computer, and the computer can be charged at any time under lighting conditions; It can also be installed on the body of the electric vehicle to supply power to the motor; The roof of the house can be covered with plastic solar cells to provide daily electricity.
(B) home machinery and electronics factory technology
Experts predict that the future home machine power plant may enable consumers to have more diversified products they need. The future home electronics factory is actually a device that uses the current inkjet printing technology. Researchers from Cornell University, Massachusetts Institute of Technology and University of California, Berkeley are quietly developing a process for producing mechanical and electronic products by using inkjet printing technology. Of course, the actual process of manufacturing products also requires existing detachable components such as circuits and switches.
For example, if the remote control of the TV set at home is broken, you can use this home computer to make one for yourself: download the digital circuit diagram from the internet and use the home electromechanical system? Print? The machine prints out the required circuit board. Print? Ink cartridge? It is filled with polymer and other materials, and a layer of circuit board is printed at a time. Experts who are doing research in this field point out that users only need to pay for digital circuit diagrams and materials used, but not for the products themselves.
A mechanical and electronic factory, what does this mean? Mechanical electronics? . But the population quality of families who can use this kind of equipment must be very high, because users must know where to download what kind of digital design drawings and make related electronic products and related parts. This is a great DIY. The advent of this device also shows that the separation of design and manufacturing is a trend in the electronic product manufacturing industry. Just use the home computer power plant, right Print? Produce the product you need, but only if the design of this product is ready-made. Of course, you can also design it yourself, so you must use professional design software and have professional knowledge in the field of machinery and electronics. So in the future, most families will use ready-made designs.
(3) Micro-optical chip technology in ultra-wideband network.
Now many families have access to the Internet through broadband. However, the infrastructure of this connection in the last section is generally outdated coaxial cable or telephone line. However, the cost of FTTH is very high, and the cost per household is about 1300 USD.
Micro-optical chips can change this situation. The use of low-light-level chips can greatly reduce the cost of optical cable to the home, so that home users can enjoy real ultra-broadband Micro-optical devices integrate optical paths and usually separated optical elements on one optical chip, which is another major technological innovation that changes the economy of telecom industry. The telecommunications industry can transmit a large amount of data at a very low cost by using optical chips. The size and cost of optical components with a price as high as tens of thousands or even hundreds of thousands of dollars may be greatly reduced by more than 90% due to the use of optical chips. This technology makes it as common for people to download a high-definition movie at home as watching sports channels today.
Wireless roaming technology
The field of wireless communication is a world with chaotic standards. Mobile communication, wireless local area network,
Military wireless communication and public security wireless network each work in a specific frequency band, and this working frequency has been set when the factory produces related hardware. So American CDMA mobile phones can't be used in Europe, and many GSM mobile phones in Europe can't be used either. This is just the usual trouble. But in some emergency situations, such as 9 1 1, the fire brigade and the police can't communicate with each other through wireless communication equipment, because the frequencies are different and the equipment is incompatible.
In order to solve this problem, some enterprises are replacing related hardware with software to be compatible with wireless communication networks with different standards and working frequency bands. This technology is called software radio. If you want to drive all over China and keep wireless Internet access all the time, no matter where you go online, Software Radio can use all kinds of wireless communication networks, whether it is the outdated analog cellular telephone network or the latest 3G wireless network, or the fashionable WiFi and Wi-Max wireless LAN.
In the future, software radio technology will enable American army soldiers, navy sailors and air force pilots to maintain wireless communication in fierce battles. It will take some time for software radio technology to enter the consumer market. However, within five years, the market of software radio will be 3 1 100 million dollars. By then, you can buy a mobile phone that can work in various wireless communication networks with different standards, and wireless roaming will be barrier-free from now on.
Abstract of intransitive verbs
Electrical and electronic technology has played an important role in all fields of our lives, and we cannot do without it. Digital TV, mobile phone, automatic navigation and automatic reversing, which were unimaginable in the past, have now become reality and play a very important role in other fields. It has changed our life and technology to a great extent, affecting everything around us every day, and will have unlimited prospects in the future.
refer to
Ye Guanghui. Present situation and development of electrical and electronic technology.
[2] Shao Min. On the current situation of electrical and electronic technology [J]. Xinjiang Education, 20 12, 9.
About the author: Tan Han (198 1-), female, from Hai 'an, Jiangsu, master, associate professor, main research direction: electrical and electronic technology.