Development trend of power supply industry

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Development trend of power supply industry [Copy link]

[&]Looking at the power supplies at home and abroad today, it is not difficult to see that the significant characteristics are: there are many categories of power supplies, involving quite comprehensive technologies and high technical content, but the core technology should be power conversion and power transmission technology, which is a combination of multiple high-tech fields such as optical, mechanical and electrical integration, new energy and high-efficiency energy saving. The current category of switching power supplies is a high-tech product with these composite technologies. Due to limited time, I will only talk about the current status and development of switching power supplies.
1. The products representing the current level are:
1. The chip voltage conversion module produced by Vicor Corporation of the United States, its parameters are:
input voltage: 32~57.6VDC; output voltage: 0.9~7.8VDC; output current: 80A, which can be matched with hundreds of amperes; operating frequency: 3.5MHz; conversion efficiency: 97%~99%; transient response and recovery time: <1μs, the transient response speed when the load changes is 20 times faster than the fastest brick converter; current density: up to 320A/in3, so the power supply volume does not exceed 0.25 cubic inches.
2. At present, the foreign switching power supply modules that can be often seen in the domestic market include:
American Vicor, Japanese LAMDA, and Swiss Ericsson.
There are many domestic module manufacturers, such as ZTE, Chengli, and Disai. The highest level of modules of these manufacturers is:
output power: 1.5~300W; efficiency: 80%~90%; switching frequency: 200~500kHz; VP-P: up to MV order of magnitude; power density: up to 320W/in3; all can be integrated and can be full-time, half-time, 1/4-time, and 1/8-time standard modules.
The mean time between failures MTBF> 200,000 hours.
2. Development trend
1. Rapid development towards diversified technology
With the great development of the market economy, the structure of China's information industry has undergone profound changes, which has driven the development of microelectronics technology and power electronics technology, and also promoted the great development of power supply technology. At present, various advanced power supply products have been widely used in agriculture, industry, energy, transportation, transportation, information, aviation, aerospace, shipping, national defense, education, culture and other fields. In today's information age, all the above industries are developing rapidly, and at the same time, more and higher requirements are put forward for the power supply industry. Such as energy saving, electricity saving, material saving, body reduction, weight reduction, pollution prevention, environmental improvement, reliability, safety, etc. This forces power supply workers to constantly explore in the process of power supply research and development, and use various related technologies to make qualified power supply products to meet the needs of all walks of life. It is precisely because of the rapid development of these technologies that the development of the power supply industry has been promoted in turn. At present, the dominant products in the power supply industry are various linear regulated power supplies, AC/DC switching power supplies for communications, DC/DC switching power supplies, AC variable frequency speed regulation power supplies, electrolytic electroplating power supplies, high-frequency inverter rectifier welding power supplies, medium-frequency induction heating power supplies, power operation power supplies, sine wave inverter power supplies, high-power high-frequency high-voltage DC regulated power supplies, green lighting power supplies, chemical power supplies, UPS, reliable, efficient and low-pollution photovoltaic inverter power supplies, wind and solar complementary power supplies, etc. The technologies related to power supply include high-frequency conversion technology, power conversion technology, digital control technology, full-resonance high-frequency soft-switching conversion technology, synchronous rectification technology, highly intelligent technology, electromagnetic compatibility technology, power factor correction technology, protection technology, parallel current control technology, pulse width modulation technology, variable frequency speed regulation technology, intelligent monitoring technology, intelligent charging technology, microcomputer control technology, integration technology, network technology, various forms of drive technology and advanced process technology. From the summary
analysis, it is not difficult to see that power supply is indeed a major device for realizing power conversion and power transmission. The power supply industry in China has become a composite high-tech product across multiple high-tech fields such as electronic information, optical, mechanical, and electrical integration, new energy and high-efficiency energy saving. It is a basic product of the electronic information industry and a product with high technical content, wide knowledge and fast replacement. Therefore, if power supply workers want to truly develop an internationally leading power supply product, they must have quite strong power supply-related technology, rich practical work experience and the most advanced technical information.
2. Cost-effectiveness is the eternal theme of winning market share.
Product price, performance indicators, brand effect and service life have always been the most concerned issues for users. Looking at several well-known power supply manufacturers at home and abroad and the world's top power supply suppliers, they all face the same pressure, namely price competition, performance competition, product excellence and even artistic competition, especially in the information age, because the information network brings users the possibility of online ordering and purchasing, which makes product prices increasingly public, forcing each power supply supplier to think hard about a series of measures to reduce costs and try to improve the cost performance to win market share.
3. High frequency, high efficiency, low voltage, standardization and modularization are the main development trends of switching power supplies
. From the perspective of packaging structure, they are moving towards thinness and even ultra-thinness. The height of the standard module was 0.5 inches in the past, but it has recently dropped to 0.375 inches. Generally, customers require a thin package size of 0.295 inches (7.5mm). The external dimensions tend to be internationally standardized, mostly 1/8, 1/4, 1/2, 3/4 and full brick structures, and the design of output terminals being compatible with each other is becoming increasingly obvious. The internal control circuit of the module tends to adopt digital control. The growth rate of non-isolated DC/DC converters is faster than that of isolated converters, and distributed power supplies are developing faster than centralized power supplies.
The application of various soft switching technologies, including passive lossless soft switching technology, active soft switching technology (such as ZVS/ZCS resonance, quasi-resonance), constant frequency zero switching technology, zero voltage, zero current conversion technology and the current synchronous rectification using MOSFET instead of rectifier diodes can greatly improve the efficiency of the module at low output voltage, and the improvement in efficiency makes it possible to realize open-type power modules without heat sinks. This type of module is the trend of module development in the world today and will be widely used. With the change of device performance, power supply efficiency is about to reach 92% (5V), 90% (3.3V), and 87.5% (2V).
In 1991, high power density was defined as 25W output power per cubic inch, which increased year by year, 36W per cubic inch in 1994, 52W per cubic inch in 1999, 96W per cubic inch in 2001, and now hundreds of W per cubic inch. The global high power density DC conversion module market is growing at an annual rate of 16.8%. The output current will increase to 80A for half brick and 50A for 1/4 brick. At present, TDK of Japan has launched a new generation of distributed isolated DC/DC converters, with parameters of 1/4 brick input voltage 42V~58V, output voltage 12V, output current 27A, efficiency 95%, and power density 236W per cubic inch; 1/8 brick input voltage 42V~58V, output voltage 12V, output current 13.5A, efficiency 95%, and power density 214W per cubic inch.
In order to reduce the size of the switching power supply, increase the power density of the power supply and improve the dynamic response, the switching frequency of the small power DC/DC converter has been increased from the current 200kHz~500kHz to more than 1MHz, but high frequency will also produce new problems, such as increased switching loss and loss of passive components, the influence of high-frequency parasitic parameters and increased high-frequency electromagnetic interference.
Quality is the lifeline of an enterprise. Throughout the development history of Chinese enterprises since the reform and opening up, it is clear that quality plays a vital role in the rise and fall of an enterprise. Especially after my country joins the WTO, power supply equipment will inevitably enter the international market. We must abide by the common principles of international trade agreements and accelerate the pace of integration into global integration. Enterprises must accept certification of various standardized specifications such as safety and quality systems. Today's power supply companies must not narrowly understand quality as the quality of their products, but should broadly understand it as the overall quality of the enterprise. Therefore, enterprises should carry out quality certification according to ISO9000 standards, clarify their own quality goals and quality policies, conduct quality education for all employees, and integrate product quality throughout the entire process of design, production and user service, so as to produce high-quality products with advanced technology and quality assurance for domestic and foreign markets.
In addition to special power supplies, general linear and switching power supplies have dozens of indicators, but the most commonly mentioned indicators are output voltage accuracy, grid regulation rate, load regulation rate, temperature coefficient, output ripple and noise, input reflected ripple current, input common mode noise current, protection performance and efficiency. The above indicators must be tested with qualified test equipment and standard test methods, and handed over to users after passing the test. It should be pointed out that various performance indicators should meet user requirements. There is no need to excessively pursue high indicators and invisibly increase the size, weight and cost of the power supply.
3. The development of power devices is the basis for the development of power supply technology
. Power MOSFET is the fastest power device at present. At present, the more advanced horizontal voltage can reach 1200V, the current can reach 60A, the frequency can reach 2MHz, and the on-resistance can reach about 0.1Ω. Improving the device's withstand voltage and reducing its on-resistance at the same time will still be the main research direction of MOSFET in the future.
The insulated gate bipolar transistor IGBT is a power electronic device composed of MOSFET and bipolar transistor. Its control pole is an insulated gate controlled field effect transistor, and its output pole is a PNP bipolar power transistor. Therefore, it has the advantages of both and overcomes the disadvantages of both. At present, the withstand voltage can reach 6.5kV and the current can reach 1.2kA. The main direction in the future is still to expand the capacity and reduce the internal resistance to reduce the conduction loss. Since IGBT often works in high frequency, high voltage and high current state, and since the power supply is the front stage of the system, it is easily affected by power grid fluctuations and lightning strikes and is easily damaged, the reliability of IGBT directly affects the reliability of the power supply. Therefore, when selecting IGBT, in addition to considering the derating, the protection design of IGBT is also extremely important.
IGCT is an upgraded product of GTO. It uses distributed integrated gate drive and shallow emitter technology. The switching speed of the device has been improved to a certain extent, while the power of the gate drive has been reduced. It is easy to use. The way out of IGCT is still high voltage and large capacity.
4. Transformer and magnetic components
With the development and maturity of power electronics technology, people gradually realize that magnetic components are not only functional components in the power supply, but also their volume, weight and loss account for a considerable proportion of the whole machine. According to statistics, the weight of magnetic components is generally 30% to 40% of the total weight of the converter, and the volume accounts for 20% to 30% of the total volume. For high-frequency power supplies with modular design, the volume and weight of magnetic components account for a higher proportion. In addition, magnetic components are also an important factor affecting the dynamic performance and output ripple of power supply output. Therefore, in order to improve the power density, efficiency and output quality of the power supply, it is necessary to conduct in-depth research on related technologies to reduce the volume, weight and loss of magnetic components to meet the needs of power supply development.
For transformers of low and medium frequency power supplies, it is recommended to use R-type transformers, which are characterized by low loss, small size, no noise and strong anti-interference ability. The current development status is that the single-phase power range has been expanded to 1VA to 100kVA, and the three-phase power range has been expanded to 315kVA. The main direction in the future is to try to overcome the disadvantage of relatively large impact current in applications.
For high-frequency transformers, they are mainly used in various forms of switching power supplies with a frequency of 20kHz to 500kHz and a power of tens of kW. The materials used are mainly amorphous, microcrystalline, ultra-microcrystalline, and soft ferrite materials. When the operating frequency of the transformer is greater than 700kHz, the eddy current loss in the transformer will increase sharply, accounting for about 80% of the total loss. In order to reduce its loss, nano additives must be added to the power ferrite material, resulting in the emergence of various transformers made of nanocrystalline soft magnetic alloys and nanocrystalline magnetic materials. The better ones currently include the high-frequency magnetic cores provided by Japan's TDK and FDK companies and the ultra-fine crystal magnetic materials launched by Germany's VAC company. This magnetic material has a very high initial magnetic permeability, generally up to tens of thousands, and the frequency used by the material is 300kHz to 1MHz, with a center frequency of 500kHz.
At present, the highest operating frequency of magnetic materials can reach 1.5MHz, which is the MnZn ferrite TP5A material developed by Zhejiang Tiantong Company in China. Transformers made of the above materials include SMD transformers, printed welding transformers, transformer modules, various forms of split transformers, plug-in transformers, PCB planar transformers and multi-layer circuit board planar transformers. As for planar multilayer transformers, Payton can currently provide a series of PM products with a power of 5 to 25kW and a frequency of 50kHz to 2MHz. It is expected that the demand for power transformers will be strong in recent years and it has become a rapidly developing hot product. The future development goal of electronic transformers is lightweight, high efficiency, and high density. The development goal of power transformers is surface mounting, high power, and high voltage.
5. The development and application of magnetic integration technology
The so-called magnetic integration technology is to wind two or more discrete magnetic bodies in the converter in a pair of magnetic cores and concentrate them together structurally. The concentrated magnetic parts are proposed to be called integrated magnetic parts. Through certain coupling methods and reasonable parameter design, the volume and loss of the magnetic bodies can be effectively reduced. In certain applications, it can also reduce the output ripple of the power supply and improve the dynamic performance of the power supply output. In addition, magnetic integration technology can significantly reduce the connection end, which can effectively reduce the loss of the terminal in high current situations.
The development history of integration technology has been more than 70 years. At present, it can realize the integration of inductors and inductors, and the integration of inductors and transformers, and is widely used in voltage adjustment modules, power factor correction, resonant converters and other occasions. With the development of future power supplies, new magnetic materials and magnetic cores will continue to emerge, which is bound to put higher requirements on magnetic integration technology. Therefore, the main focus of this technology in the future will still be to further broaden the application field of magnetic integration technology, expand application occasions, and continuously study magnetic integration technology suitable for new magnetic materials and magnetic core structures, so as to contribute to the reduction of power supply size and weight.