Semiconductor devices everywhere, has become the cornerstone of building an information society

The invention and application of semiconductor devices profoundly changed the course of human history development in the past 50 years. Into the 21st century, semiconductor devices everywhere, has become the cornerstone of the construction of information society. At the same time, the role of power semiconductors in improving the efficiency of power conversion makes it the cornerstone of a Low-carbon society. The energy-saving effect of semiconductor technology is obvious. The world's first electronic-tube computer ENIAC weighs 30 tonnes and consumes up to 200kW of power, and today's semiconductor computing equipment, which has the same function, weighs only a few grams and consumes less than 1W. At the same time, power semiconductors play a key role in the process of energy conversion, storage and transportation of solar photovoltaic and wind power plants. It can be seen that the use of renewable energy and the improvement of efficiency of power conversion devices are inseparable from the innovative applications of semiconductor technology.

Si si device has undergone many years of development has changed the face of household appliances, DC speed regulation technology has become home air-conditioning and other motor to improve the efficiency of the main technical measures. It is worth noting that the technical development of new devices, such as SIC, gallium nitride Gan and gallium oxide Ga2o3, can promote the development of home appliances technology by reducing the energy consumption and increasing the efficiency of power conversion.

To improve the efficiency of energy use is a topic of broad significance. As far as household appliances are concerned, improving efficiency in a narrow sense is mainly to improve the energy use efficiency of household appliances in the running process. At present, countries have basically been monitoring the energy efficiency of household appliances, energy efficiency labelling, energy efficiency rating system is a more common way of regulation. In general, it is necessary to consider the energy consumption of the manufacturing process, the energy consumption of raw materials and the indirect energy efficiency effect during the operation. The efficiency problem discussed in this paper is limited to narrow scope, and it only aims at the measures of improving energy use efficiency by using technology progress, and expounds the effect of power semiconductors on improving energy use efficiency of household appliances.

Material substitution of power semiconductors

Household electricity accounts for about 1/3 of the total electricity consumption in the United States. The number of households in the United States is forecast to grow by 11% over the next 10 years, and home electricity will rise by only 6% per cent, thanks to power semiconductors. According to a survey, all power applications in the United States are 6%~10% power from AC AC to DC DC, because the existing power supply efficiency is poor, the United States total power consumption 3%~4% is consumed within the power supply; to improve product design, The use of microelectronic control devices and power semiconductors such as FET and diodes to improve power efficiency can save the 1%~2% of the total power consumption in the United States. This means that power semiconductor technology has the potential to save 3 billion ~60 billion dollars a year.

Today, the development of power semiconductor technology not only embodies in the application of the increasingly wide range of high-efficiency LED lighting appliances, even in air-conditioning, refrigerators, washing machines, electromagnetic stoves and other high-power home appliances, power semiconductor applications have exceeded the scope of the controller-driven power. High Power Semiconductor drive technology has changed the original operation mode and energy conversion process of the product, and the energy saving effect is remarkable. To improve the power conversion efficiency of household appliances and to reduce standby energy consumption is a commonly used energy-saving measures. Semiconductor manufacturing enterprises, power conversion components manufacturing enterprises and household appliances machine manufacturers are working to make these losses smaller.

Motor is the main power consumption component of most white home appliances, although the role of speed control and variable torque control technology in improving the efficiency of the motor has long been known and widely used in the industrial field, but before the advent of power semiconductors, these technologies are difficult to apply to the compact structure, maintenance of relatively inconvenient home appliances. For example, the DC motor with speed regulating function is equipped with a mechanical commutator before the semiconductor commutator is used, and the life of the mechanical commutator is usually less than 1000h, and the driving power is bulky and expensive. The late 1970s, Japanese enterprises will apply power semiconductor technology to air-conditioning refrigeration compressor speed control, the basic implementation of the whole machine 100,000 H maintenance-free, while driving the shape of the power supply is greatly reduced, can be placed inside the air-conditioning, and the price greatly reduced. The Japanese market in less than 10 time to basically complete the transition from the fixed speed to the frequency conversion speed. Although the frequency conversion power consumption of about 10% of the power, but the use of variable frequency speed control in the operation of the variable speed, variable torque function, the average residential air-conditioning power consumption reduced by about 30%. At the same time, in the winter heat pump operating mode with a substantial increase in heat production capacity, which also promotes the heat pump heating technology widely used.

The development trend of power semiconductors, such as metal oxide semiconductor field effect transistor MOSFET, insulated gate bipolar transistor IGBT and diode, which plays a role in inverter and transformer and other devices, is changing from the current mainstream SI semiconductor material to semiconductor materials such as SIC and Gan, Significant progress has been made in improving efficiency and reducing volume.

The Institute of Solar Systems, Fraunhofer of the German Fraunhofer Association for Applied Research, ISE has now increased the efficiency of its inverter to 98.5%, and the power loss of the new inverter is about 50% lower than the original equivalent inverter. The mechanism of using SIC device to replace SI device in the single-phase inverter with rated power of 5kW is the key to improve the efficiency remarkably. The SIC devices, produced by Cree, the US, have solved the manufacturing process of 6-inch sic floors in 2010 and produced mass production, creating the conditions for a sharp drop in the manufacturing costs of SIC devices.

The higher efficiency of a new type of semiconductor device is mainly due to low power consumption in the device. In the same circuit structure, the diode from SI material into sic material, power consumption can be reduced by about 30%, if the same transistor replacement, power consumption can be reduced by about 50%. Power consumption is reduced and calorific value decreases, thus realizing energy saving of power conversion devices.

In addition to low power consumption, gan and sic have the characteristics suitable for miniaturization. First of all, the devices made of the two kinds of materials can realize the high speed switch of SI components, so that the size of the peripheral circuit components such as inductor is greatly reduced, thus realizing the miniaturization of the electric power conversion device circuit. Secondly, sic and Gan components can also be used in the SI components could not adapt to more than 200 ℃ high temperature environment, in the same calorific condition, can reduce the power conversion device cooling device dimensions.

With the acceleration of the industrialization of Gan and SIC power semiconductors, it is urgent to develop a new type of peripheral circuit which can make full use of its characteristics, such as the design of driving circuit for high speed work and the countermeasure of electromagnetic noise on the precondition of high-frequency switch. To enable these power semiconductors to work in more than 200 ℃ high-temperature environment, in addition to the use of high heat resistance and low-cost solder materials, in the chip installation, but also the use of high-temperature packaging materials. The progress of these peripheral circuit technology is the key to exert the effect of Gan and SIC devices.

The industrialization of silicon carbide devices

October 2010, the Japanese Mitsubishi Electric Company announced in the 2011 refrigeration year began to sell the use of sic-made Schottky barrier diode SBD as a DC speed control compressor power supply home air-conditioning. This is the world's first application of SIC power semiconductor appliances, marking the home appliances industry to SIC as the representative of the new generation of power semiconductor industrialization began.

The first batch of domestic air-conditioning using SIC devices is Mitsubishi Motor Fog Peak Moveeye series products, including rated refrigeration capacity of 2.8kW Msz-zw281s and rated refrigeration capacity of 3.6kW msz-zw361s two models. According to the plan, Fog peak Moveeye series will cover the rated refrigeration capacity of the range of 2.2kw~7.1kw, other models will be in succession to SIC devices to replace SI devices. Although the price of SIC devices is still high, but Mitsubishi Motor does not reflect the cost changes in the overall price, but to let the way to digest the increase in cost.

This batch of air conditioner still uses the insulated gate type bipolar transistor igbt, changes si diode to SIC-SBD, only uses in the DC speed control compressor to drive the power supply. From the point of view of energy saving, using SIC-SBD, the power conversion loss of the compressor drive power can be reduced by about 60%, and the total electricity consumption of air conditioner is reduced by 2%. If it is necessary to further improve the power conversion efficiency and reduce the external dimensions of the driving power supply, all other power semiconductors should be changed to SIC devices to replace IGBT with Sicmosfet. Mitsubishi Motor to promote the accelerated development of SIC market, so that the price of SIC devices into a reasonable range, and strive to achieve SICMOSFET in 2013-2014 years of industrialization objectives, so as to gain a competitive advantage in the power semiconductor market. Mitsubishi Motor plans to replace the IGBT with the Sicmosfet,sic device will not only apply to the compressor drive power supply, but also to the main control Panel power supply part. If all SIC devices are used, the overall size of the power electronics module of the main control panel will be reduced to around 50%.

Mitsubishi Motors has issued a series of energy-saving prospects for the use of all SIC power conversion devices. Using SIC-SBD and Sicmosfet output power of 11kW motor inverter, and Mitsubishi Motors using SI devices manufactured by the same kind of machine, power consumption is reduced by 70%. At the same time, the volume of sic inverter is less than SI frequency converter, the whole volume of SIC device is only used about 1/4 of SI device. In addition, the power consumption of the 3.7kW sic motor inverter produced by Mitsubishi Motor is about 54% lower than that of SI motor inverter.

The results show that the energy saving effect of SIC motor inverter with 20kW output power is more significant. Rated output power of 20kW, switching frequency of 20kHz sic motor inverter, and the use of ordinary si made of igbt similar products, power loss of about 90%. According to the introduction, this is by shortening the switching time to achieve the increase of SIC device switching speed, thereby reducing power consumption. In order to speed up the switching speed, the gate drive circuit needs to realize high speed, improve the driving mode, reduce the parasitic inductance in the driving circuit, and shorten the switching time to about 50%. At the same time, increasing the switching speed may cause the surge voltage to increase, thereby damaging the SIC device. To avoid this problem, the new product reduces the parasitic inductance in the circuit by improving the configuration and circuit wiring of the SIC devices to suppress the surge voltage. Compared with the SI motor inverter with output power of 20kW, the parasitic inductance of sic motor inverter is only the 1/5~1/10 of the former.

February 2011, Mitsubishi Motor announced the successful development of transistors and diodes are using SIC power semiconductor devices-"full sic" intelligent power Module IPM. In addition to the use of SIC devices, IPM also has a overcurrent protection circuit built into the module with the drive circuit. In general, it is difficult to improve both current density and loss in power components, and IPM can achieve this kind of mutual benefit because of the use of SIC power components. Compared with the IGBT with SI device, the current density of the new module is increased by about 3 times times, and the power consumption of inverter is reduced by about 70%. In addition, the new module is about half the size of the original equivalent module.

The Central Institute of Japanese Electric Power has successfully developed the inverter using SIC diode and the connection of distributed power system. The inverter's rated output power is 3.3kW, the output voltage is single-phase 200V, the conversion efficiency is as high as 96.4%, is the current similar power electronic conversion device of the most efficient power conversion products, mainly used in household solar power generation system and fuel cell system, such as power regulation. The inverter is composed of a chopper that regulates DC voltage and a single-phase inverter that converts DC to AC, and achieves high conversion efficiency by reducing the recovery current of the diode on the chopper circuit. Compared with the highest performance product of Si diode, the power loss of the inverter was reduced by 15%, and the device volume shrank by 15% by increasing the switching frequency of the chopper circuit.

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