Electronic technology highlights energy-saving functions; new-type devices begin to emerge

by qxing0001 on 2009-06-12 15:49:34

The primary significance of developing the power electronics industry, as noted on the Electronics Information Network (http://www.dianzixx.com/), lies in saving electricity. Therefore, high efficiency is our basic requirement for power electronic devices. The new type of power electronic device IGBT (Insulated Gate Bipolar Transistor) has already played the role of an "emergency vanguard" in energy conservation in multiple fields such as industrial control, consumer electronics, and automotive electronics. In the field of new energy, power electronic devices are also indispensable.

In the early stages of its development (the 1960s to the 1980s), power electronic devices were mainly applied in the industrial and power systems sectors. Over the past 20 years, with the rapid development of the 4C industries (communications, computers, consumer electronics, and automobiles), the application scope of power electronic devices has significantly expanded. Its technology has become a crucial foundation for aviation, aerospace, trains, automobiles, communications, computers, consumer electronics, industrial automation, and other scientific and industrial departments.

Power electronics is a key technology for energy conservation

Power electronics technology is a key technology for achieving high-efficiency energy conservation, transforming traditional industries, and promoting mechatronics. It serves as a bridge between weak electrical control and strong electrical operation, between information technology and advanced manufacturing technology. It is an important foundational technology for China's national economy and a significant supporting technology for modern science, industry, and defense. Power electronic devices are the foundation and core of power electronics technology, and the development of power electronics technology revolves around the birth and perfection of various new types of power electronic devices.

Currently, the primary significance of developing the power electronics industry lies in saving electric energy. Professor Kang Baowei from the School of Electronic Information and Control Engineering at Beijing University of Technology once told the China Electronics News: "To solve the problem of energy shortages, besides 'opening up new sources,' the potential of 'conservation' is also enormous. The first measure for conservation is the development and promotion of power electronic devices. For example, according to statistics, the electricity used by motors in China accounts for more than 60% of the country's total electricity generation. If all motor drives across the country use power electronic devices for frequency conversion speed regulation, the electricity consumed by motors can be reduced by about 1/4 to 1/3, meaning a savings of 15% to 20% of the country's total electricity generation."

Bai Jibin, vice chairman and secretary-general of the Chinese Society of Electrical Engineering's Power Electronics Society, told reporters from the China Electronics News that energy conservation and high efficiency are the main characteristics of power electronics technology. This is mainly because power electronic devices generally operate in a relatively ideal switching state. The main technical difference between power electronics and information electronics is the issue of efficiency. For low-level circuits used in information processing, few require their efficiency to exceed 15%, while the efficiency of power circuits in power electronics technology must be above 85%. It is evident that high efficiency is the fundamental requirement for power electronic devices.

IGBT performs well in multiple fields

To achieve the goal proposed in the "Eleventh Five-Year Plan" of reducing energy consumption per unit of GDP by about 20% compared to the end of the "Tenth Five-Year Plan," the key is to effectively reduce the power consumption of large current and high voltage applications during the industrial production process, such as AC motor control, inverters, relays, switch-mode power supplies, frequency converters, industrial transmission equipment, locomotive and train power supplies, and heating system transmission devices in industrial automation applications.

All these AC control applications require core power devices capable of generating large currents and high voltages. As a representative of new power electronic devices, IGBT (Insulated Gate Bipolar Transistor) is increasingly gaining attention in the industry. IGBT is a bipolar device with a MOS structure that combines the high-speed performance of power MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) and the low-resistance performance of bipolar transistors. It has the advantages of voltage-type control, high input impedance, low drive power, fast switching speed, high operating frequency, and a large safe operating area, making IGBT devices ideal power switching devices for high-power industrial automation applications. The application range of IGBTs generally falls within the areas requiring voltage tolerance of 600V or higher, current of 10A or higher, and frequency of 1kHz or higher.

Besides applications in industrial control, with the gradual enhancement of people's awareness of energy conservation, the demand for IGBTs in consumer electronics is also rapidly increasing. For instance, in induction heating applications, IGBTs have become key components in induction cookers due to their ability to withstand high voltage and have a relatively high switching frequency; frequency-controlled air conditioners, frequency-controlled washing machines, and other frequency-controlled appliances mainly use IGBT intelligent modules that integrate drive circuits and protection circuits, simplifying circuit design; in lighting applications, IGBTs are also required components for high-pressure gas discharge lamps (HID), lamp dimmers, and high-frequency ballast lights. Moreover, in the automotive electronics field, IGBTs have replaced Darlington transistors to become the preferred component for car ignition systems. Paul Roland, director of the Analog, Power, and MEMS Division of STMicroelectronics Asia-Pacific, told reporters from the China Electronics News that high-current IGBTs are increasingly being used in the main converters of hybrid vehicles.

Opening new sources also relies on power electronics

Globally, solving the problem of energy shortages involves two fundamental approaches: "opening new sources" and "conservation." Using power electronic devices to improve system efficiency and reduce energy consumption falls under the category of "conservation," whereas developing new energy sources to replace non-renewable resources such as coal, oil, and natural gas belongs to "opening new sources." In fact, in the field of "opening new sources," power electronic devices also play an important role.

Solar power generation has always been an important area for exploring new energy sources. Over the past 20 years, China's photovoltaic industry has developed rapidly. From 1990 to 2007, the output of China's solar cells increased by 1641 times. In 2007, China's solar cell output was 821MW (megawatts), accounting for 22% of the world's total output, ranking second in the world. To connect the DC power generated by solar power plants to the grid, it is necessary to convert DC power into AC power using an inverter. Due to the rising demand for renewable energy, the electronic market for solar inverters is also growing continuously. These inverters require extremely high efficiency and reliability. For solar inverters that need 1200V power switches, IGBTs are an ideal choice.

In the field of wind power generation, the application of power electronic devices in converters plays a crucial role. Sen Min, general manager of Mitsubishi Electric Mechatronics (Shanghai) Co., Ltd., told reporters from the China Electronics News: "Wind power generation converters serve as a bridge connecting generators and the grid. Through the converter, the rotor speed of wind turbines can change according to wind speed, thus maximizing the utilization efficiency of wind energy, effectively reducing load, and ensuring that the frequency of the output power remains consistent with the grid frequency when the rotor speed and the driven motor speed change."

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