Chapter 1: Introduction to Power Electronics Systems
1) Definition Power Electronics: is the electronics applied to conversion and control of electric power. Range of power scale : milliwatts(mW) megawatts(MW) gigawatts(GW) A more exact explanation: The primary task of power electronics is to process and control the flow of electric energy by supplying voltages and currents in a form that is optimally suited for user loads.
Conversion of electric power Other names for electric power converter: -Power converter -Converter -Switching converter -Power electronic circuit -Power electronic converter
Industrial applications Motor drives Electrolysis Electroplating Induction heating Welding Arc furnaces and ovens Lighting • Transportation applications Trains & locomotives Subways,Trolley buses Magnetic levitation Electric vehicles Automotive electronics Ship power systems Aircraft power systems
Utilitystems applications • High- voltage dc transmission(HVDC) • Flexible ac transmission(FACTS) • Static var compensation & harmonics • suppression • Custom power & power quality control • Supplemental energy sources : • wind, photovoltaic, fuel cells • Energy storage systems • Power supplies for electronic equipment • Telecommunications • Computers • Office equipment • Electronic instruments • Portable or mobile • electronics
Residential and home appliances • Lighting • Heating • Air conditioning • Refrigeration & freezers • Cooking • Cleaning • Entertaining • Applications in space technology Spaceship power systems Satellite power systems Space vehicle power systems
Other aplications Nuclear reactor control Power systems for particle accelerators Environmental engineering • Trends It is estimated that in developed countries now 60% of the electric energy goes through some kind of power electronics converters before it is finally used. Power electronics has been making major contributions to: --better performance of power supplies and better control of electric equipment --energy saving --environment protection reduction of energy consumption leads to less pollution reduction of pollution produced by power converters direct applications to environment protection technology
Major issues in power electronics • How to meet the requirement of the load or gain better control of the load • How to improve the efficiency • for reliable operation of power semiconductor devices • for energy saving • How to realize power conversion with less volume, less weight, and less cost. • How to reduce negative influence to other equipment in the electric power system and to the electromagnetic environment.
An application-specific integrated circuit (ASIC) is an integrated circuit (IC) customized for a particular use, rather than intended for general-purpose use. For example, a chip designed solely to run a cell phone is an ASIC.
The concept and features Power electronic devices: are the electronic devices that can be directly used in the power processing circuits to convert or control electric power. Very often: Power electronic devices= Power semiconductor devices Major material used in power semiconductor devices——Silicon
Features of power electronic devices a) The electric power that power electronic device deals with is usually much larger than that the information electronic device does. b) Usually working in switching states to reduce power losses c)Need to be controlled by information electronic circuits. d)Very often, drive circuits are necessary to interface between information circuits and power circuits. e)Dissipated power loss usually larger than information electronic devices —special packaging and heat sink are necessary.
The insulated-gate bipolar transistor or IGBT is a three-terminal power semiconductor device, noted for high efficiency and fast switching. The Integrated Gate Commutated Thyristor (IGCT) is a new high-power semiconductor device. An IGCT is a sub family of the GTO thyristor and like the GTO thyristor is a fully-controllable power switch.
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Examples of commercial Power Diodes
Controllable Switches (Power Transistors) • Can be turned “ON”and “OFF” by relatively very small control signals. • Operated in SATURATION and CUT-OFF modes only. • No “linear region” operation is allowed due to excessive power loss. • In general, power transistors do not operate in latched mode. • Traditional devices: Bipolar junction transistors (BJT), Metal oxide silicon field effect transistor ( MOSFET), Insulated gate bipolar transistors (IGBT), Gate turn-off thyristors (GTO) • Emerging (new) devices: Gate controlled thyristors (GCT). Or MCT (MOSFET controlled Thyristor)