Power electronics technology is a new electronic technology applied in the field of powerPower electronic devices(e.gThyristor，GTO，IGBTAnd so on) to transform and control electric energy.The "power" power transformed by power electronics technology can be as large as hundreds of MW or even GW, or as small as several W or less than 1W. Unlike information electronics technology, which focuses on information processing, power electronics technology is mainly used for power transformation.
Power electronic technology is divided into power electronic device manufacturing technology andConverter technology(Rectifier, inverter, chopper, frequency conversion, variable equality) two branches.
It has become an indispensable subject in modern electrical engineering and automationSpecialized basic courses, which plays an important role in training the professional talents.
The name Power Electronics appeared in the 1960s.In 1974, WNewell uses an invertedtriangle(as shown in Figure 1) describes power electronics, and believes that it is composed ofelectrodynamics, Electronics andcontrol theoryThreeInterdisciplinaryAnd formed.This view is widely accepted all over the world."Power electronics" and "power electronics technology" are respectivelyEngineering technology2 different angles.
It is generally believed that power electronic technology was born in 1957 in the United StatesGeneral Electric CompanyThe firstThyristorAs a symbol, the concept and foundation of power electronics technology is due to thyristor and thyristorConverter technologyIt is established by the development of.Electronic technology for power conversion has existed before, so the period before the emergence of thyristor can be called the prehistoric or dawn period of power electronic technology.Since the late 1970sGate turn off thyristor(GTO), PowerBipolar transistor（BJT），Power field-effect transistor（Power-MOSFET)Fully controlled deviceFull speed development (fully controlled devices are characterized byBaseCan be turned on and off).The power electronics technology has taken on a new lookDevelopment stage。In the late 1980s, insulated gate bipolar transistor（IGBTCan be regarded as the combination of MOSFET and BJT)Drive powerSmall, fast switching speed,On stateLow voltage drop, current carrying capacity and superior performance make it the leading device in modern power electronics technology.To makePower electronic deviceIts structure is compact and its volume is reduced. It often makes several power electronic devices and necessary auxiliary devices into modules, and later drives, controls,protection circuit It is integrated with power devices to form a power integrated circuit (PIC).The power of PIC is still small, but this represents power electronicstechnological development An important direction of.
utilizePower electronic devicesTechnology to achieve industrial scale power conversion, sometimes calledPower Electronics。Generally, it converts one form of industrial power into another.For example, setalternating currentIt can be converted into DC electric energy or AC electric energy;Transform power frequency power supply into power supply with required frequency of equipment;In normalAC power supplyIn case of interruption, useinverter(SeePower converter）Convert the DC electric energy of the storage battery into power frequency AC electric energy.The application of power electronics technology can also realize the conversion between non electric energy and electric energy.For example, usingsolar celltakeSolar radiant energyConvert into electric energy.Different from electronic technology, the electric energy transformed by power electronic technology is used as energy rather than as the carrier of information sensing.So people focus on what can be transformedelectric power。
Power electronics technology is based on electronics, electrical principles andAuto-ControlIII UndergraduateEmerging disciplines。Because it is a high-power electrical technology, and mostly serves the industry applying strong electricity, it is often classified as electrician.Power electronic technology mainly includes power electronic devicesPower electronic circuitandPower electronic deviceAnd its system.Semiconductor is the basic material of power electronic devices, and the most commonly used materials aremonocrystalline silicon；Its theoretical basis is semiconductor physics;itsProcess technologybysemiconductor device technology.Modern new power electronic devices are widely usedmicroelectronicsTechnology.Power electronic circuits absorb the theoretical basis of electronics. According to the characteristics of devices and the requirements of power conversion, many power conversion circuits have been developed.These circuits also include various control, trigger, protection, display, information processing, relayelectrical contactetc.Secondary circuitAnd peripheral circuits.Using these circuits, according toApplication ObjectThe difference between them makes up the whole machine for various purposes, which is called power electronic device.These devices often form a system with loads, supporting equipment, etc.ElectronicsElectrotechnicsAutomatic control, signal detection and processing and other technologies are often used in these devices and systems.
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(1) Optimize the use of electric energy.Through the treatment of electric energy by power electronic technology, the use of electric energy is reasonable, efficient and economical, and the use of electric energy is optimized.For example, in terms of power savingFan water pump、Electric traction、rolling millSmelting, light industry papermakingIndustrial kiln、induction heating, electric welding, chemical industry, electrolysis and other 14 aspects of the survey, the total potential power savings equivalent to the 1990 nationalPower generation16%, so the promotion and application of power electronics technology is an energy-saving itemStrategic measuresThe general energy-saving effect can reach 10% - 40%, and many devices have been included in the promotion and application projects of energy conservation in China.
(2) RenovationTraditional industriesAnd developmentMechatronicsetc.Emerging industries。according todeveloped countryIt is predicted that 95% of electric energy will be processed by power electronic technology before being used in the future, that is, industrial and civilelectromechanical equipmentMedium, 95% is related to electric powerElectronic industryIn particular, power electronics technology is a medium for weak current to control strong current, and an important interface between electromechanical equipment and computers. It is adopted by traditional industries and emerging industriesmicroelectronicsTechnology has created conditions and become the guarantee and basis for computer to play its role.
(3) High frequency andFrequency conversion technologyThe development of will make electromechanical equipment break through the tradition of power frequency and develop towards high frequency.Achieve the bestwork efficiency, which will reduce the volume of electromechanical equipment several times, dozens of times,response speedIt can achieve high speed, adapt to any reference signal, achieve no noise and has new functions and uses.
(4) The progress of power electronics intelligence will, to a certain extentinformation processingIt is integrated with power processing to integrate microelectronics technology and power electronics technology, and its development may lead to major reforms in electronic technology.Some even suggest that the next revolution in electronics will take place inindustrial equipment And power grid, power electronics technology will bring people to theSecondary electronThe edge of revolution.
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The first mercury arc of glass appeared in 1902rectifier。In 1910, an iron clad mercury arc rectifier appeared.Use mercury arc rectifier instead of mechanical switch andInverterThis is the beginning of power electronics technology.Trial production in 1920Cupric oxideRectifier, selenium rectifier appeared in 1923.In the 1930s, these rectifiers began to be widely used in power rectifier devices.In the late 1940stransistor。In the early 1950s, transistors were developed to high power, and semiconductors were usedSingle crystal High power madediodeIt has also been developed.In 1954,General Electric Company of Sweden(ASEA) firstly used mercury arc tube for high-voltage rectification and inverter, andDC transmission lineIt can transmit 20 megawatts of power.In 1956, made by American J. MooreThyristorPrototype.In 1957, the American RA. York made practical thyristor.Thyristors were used in the late 1950sPower electronic deviceSince the 1960s, it has been rapidly popularized and developed a series of derivative devices, expanding theapplication area 。 Power electronic circuitWith the popularization of thyristor application, many power electronic circuits have been developed. According to their functions, they can be divided into: ①rectifier circuit ；②Conversion of DC electric energy into AC electric energyInverter circuit；③Converting one form of AC power into anotherAC conversion circuit；④Converting one form of DC electric energy into another form of DC electric energyDC conversion circuit。These circuits all contain thyristor, and each thyristor needs correspondingtrigger。So there are many trigger control circuits in combination with these power electronic circuits.According to the devices used, these control circuits can generally be divided into three generations.The first generation control circuit is mainly composed of discreteelectronic component(such as transistor and diode).Until the late 1980s, it was still used quite a lot.The second generation consists of integrated circuits.Since the first integrated circuit appeared in the United States in 1958, it has developed rapidly.It is applied to the control circuit of power electronic device, which makes its structure compact, function and reliability improved.The third generation is controlled by microcomputer.Since the 1970s, the development of microcomputer has made power electronic devices further progress towards the direction of intelligence.With the development and perfection of power electronic circuits, many types of power electronic devices composed of thyristors are emerging.Such as high-powerElectrolytic power supply、Welding power supply, for electroplatingDC power supply；DC and AC tractionDC drive, CommunicationCascade speed regulation、frequency control Power supply for equal transmission;Excitation, reactive static compensationHarmonic compensationPower electronic devices for power systems such as;Low frequency, medium frequencyHigh frequency power supplyAll kinds of non power frequency power supply, especially the medium and high frequency power supply for induction heating;UPS、AC regulated power supplyAnd other industrial power electronic power supplies;variousVoltage regulatorwait.These power electronic devices are different from traditional motors-Generator SetCompared with, it has higher electrical efficiency (take the motor generator set with a capacity of 10 kW to hundreds of kW and a frequency of 1000 Hz as an exampleRated loadThe efficiency η=80%, and decreases significantly with the decrease of load. If thyristor power supply is used, η ≥ 92%, and changes little with the load), so it has obvious energy-saving effect.The power electronic device is a static device with small floor area, light weight and easy installation (taking the welding power supply as an example, compared with the rotary welding machine, the weight is reduced by 80% and the energy is saved by 15%).At the same time, power electronic devices are often easy to adjust frequency, voltage, etc., with fast response and multiple functions,Degree of automationHigh, so it can not only save energy but also improveproductivityandproduct quality, save raw materials, and often improve the working environment.However, most power electronic devices are electronic switching devices, which often produceHarmonic interference, and sometimessurrounding environmentCause certainHigh frequency interference, which must be properly solved when designing these devices and systems (seeHigh order harmonic suppression）。
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From the middle of 1950s to the end of 1970sdiode、bipolar power transistor Power electronics based on and thyristor application (especially thyristor)technological development Quite mature.Since the late 1970s, the development of two aspects has caused a huge impact on power electronics technology.One is the development of microcomputer, which affects the control system of power electronic devicesFault detectionInformation processing has played an important role and will continue to develop in the future;The second is microelectronics technologyOptical fiber technologyIsopermentPower electronic devicesMore new generation power electronic devices have been developed.Including divisionCommon thyristorIn addition to developing to higher capacity (6500 V, 3500 A),Gate turn off thyristor(GTO) voltage has reached 4500 V and current has reached 2500~3000 A;Bipolar transistorIt is also developing towards greater capacity. In the middle and late 1980sindustrial productUp to 1400 volts,Maximum currentUp to 400 A,working frequency It is much higher than the thyristor, and the current gain can reach 75~200 with Darlington structure.With the development of optical fiber technology, the United States and Japan successively developedLight controlled thyristorAnd used forDC transmission system。Compared with the electrically triggered thyristor, this kind of light control tube simplifiestrigger circuit, improvedInsulation levelandAnti interference capability, can makeConverter equipmentThe development towards small size and light weight not only reduces the cost, but also improves the reliability of operation.At the same time, field controlled power electronic devices have also been developed, such asPower field-effect transistor(power MOSFET) and power static induction transistor (SIT) have reached the voltage and current levels of kilovolt and tens to hundreds of amperes, and the working frequency of small and medium capacity can reach the megahertz level.A new generation of power electronic devices, such as insulated gate bipolar transistor (IGT orIGBT）AndMOS controlled thyristor(MCT) is also emerging, and its capacity has been quite large.These new devices all haveGate poleThe turning off capacity and operating frequency can be greatly improved, making the power electronic circuit more simple, and improving the volume, weight, efficiency, performance and other indicators of power electronic devices. It will enable the development of power electronic technology to a new stage.At the same time, power electronic devices, power electronic circuits and power electronic devicescomputer simulationandSimulation technologyIt is also developing constantly.
