Power Electroni cs Introduction Power E l e ct r o n i cs 2 Outline I. What is power electronics? II. The history III. Applications IV. A simple example V. About this course Power E l e ct r o n i cs 3 I. What is power electronics? 1) Definition 2) Relation with information electronics 3) The interdisciplinary nature 4) Position and significance in the human society Power E l e ct r o n i cs 4 Power Electronics: A more exact explanation: is the electronics applied to conversion and control of electric power. Range of power scale : milliwatts(mW) megawatts(MW) gigawatts(GW) 1) Definition 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. Power E l e ct r o n i cs 5 Conversion of electric power Other names for electric power converter: -Power converter -Converter -Switching converter -Power electronic circuit -Power electronic converter Electric Power Converter Power output Power input Control input Frequency, magnitude, number of phases AC (Alternating Current) MagnitudeDC(Direct Current) Changeable properties in conversion Two types of electric power Power E l e ct r o n i cs 6 Classification of power converters DC AC AC AC to DC converter (Rectifier) AC to AC converter ( Fixed frequency : AC controller Variable frequency: Frequency converter or cycloconverter ) DC DC to DC converter (Chopper) DC to AC converter (Inverter) Power output Power input Power E l e ct r o n i cs 7 Power electronic system Generic structure of a power electronic system Power Converter Power output Power input Controller Feedforward Feedback Reference ( measurements of output signals ) ( measurements of input signals ) Control is invariably required. Power converter along with its controller including the corresponding measurement and interface circuits, is also called power electronic system. Control input Power E l e ct r o n i cs 8 A typical power electronic system The task of power electronics has been recently extended to also ensuring the currents and power consumed by power converters and loads to meet the requirement of electric energy sources. Electric Motor light heating other electric equipment power converter Power Converter Source Power input Power output Load Controller Reference Electric utility battery other electric energy source power converter 7 J J J J P 7 P Measurements Power E l e ct r o n i cs 9 A Classification of electronics by processing object 2) Relation with information electronics Electronics Information electronics: to process information Power electronics: to process electric power Other classifications of electronics Electronics Vacuum electronics: using vacuum devices, e.g, vacuum tubes devices Solid (Solid state) electronics: using solid state devices, e.g, semiconductor devices Electronics Applied electronics: application of electronic devices to various areas Physical electronics: physics,material,fabrication, and manufacturing of electronic devices Power E l e ct r o n i cs 10 3) The interdisciplinary nature William E. Newell’s description Electronics D e v i c e s , c i r c u i t s Power S t a ti c & r o ta ti n g p o w e r e q u i p m e n t Power Electronics Continuous, discrete Control Power electronics is the interface between electronics and power. Power E l e ct r o n i cs 11 Relation with multiple disciplines Power electronics is currently the most active discipline in electric power engineering. Power electronics Systems & Control theory Circuit theory Signal processing Simulation & computing Electronics Solid state physics Electromagnetics Power systems Electric machines Power E l e ct r o n i cs 12 4) Position and significance in the human society Electric power is used in almost every part and everywhere of modern human society. Electric power is the major form of energy source used in modern human society. The objective of power electronics is right on how to use electric power, and how to use it effectively and efficiently, and how to improve the quality and utilization of electric power. Power electronics and information electronics make two poles of modern technology and human society: information electronics is the brain,and power electronics is the muscle. Power E l e ct r o n i cs 13 II. The history The thread of the power electronics history is the break-through and evolution of power electronic devices late 1980s mid 1970s19571900 Mercury arc rectifier Vacuum-tube rectifier Thyratron Invention of Thyristor Power diode Thyristor Applicaication of fast-switching fully-controlled semiconductor devices GTO GTR Power MOSFET Thyristor (microprocessor) IGBT Power MOSFET Thyristor (DSP) Pre-history 1st phase 2nd phase 3rd phase Power E l e ct r o n i cs 14 III. Applications Industrial Transportation Utility systems Power supplies for all kinds of electronic equipment Residential and home appliances Space technology Other applications Power E l e ct r o n i cs 15 Industrial applications Motor drives Electrolysis Electroplating Induction heating Welding Arc furnaces and ovens Lighting Power E l e ct r o n i cs 16 Transportation applications Trains & locomotives Subways Trolley buses Magnetic levitation Electric vehicles Automotive electronics Ship power systems Aircraft power systems Power E l e ct r o n i cs 17 Utility systems applications High-voltage dc transmission(HVDC) Flexible ac transmission(FACTS) Static var compensation & harmonics suppression: TCR, TSC, SVG, APF Custom power & power quality control Supplemental energy sources : wind, photovoltaic, fuel cells Energy storage systems HVDC Power E l e ct r o n i cs 18 Power supplies for electronic equipment Telecommunications Computers Office equipment Electronic instruments Portable or mobile electronics server computer Telecommunication Power E l e ct r o n i cs 19 Residential and home appliances Lighting Heating Air conditioning Refrigeration & freezers Cooking Cleaning Entertaining Power E l e ct r o n i cs 20 Applications in space technology Spaceship power systems Satellite power systems Space vehicle power systems Power E l e ct r o n i cs 21 Other applications Nuclear reactor control Power systems for particle accelerators Environmental engineering Power E l e ct r o n i cs 22 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. reduction of energy consumption leads to less pollution reduction of pollution produced by power converters direct applications to environment protection technology Power electronics has been making major contributions to: --better performance of power supplies and better control of electric equipment --energy saving --environment protection Power E l e ct r o n i cs 23 IV. A simple example A simple dc-dc converter example Input source:100V Output load:50V, 10A, 500W How can this converter be realized? Power E l e ct r o n i cs 24 Dissipative realization Resistive voltage divider Power E l e ct r o n i cs 25 Dissipative realization Series pass regulator: transistor operates in active region Power E l e ct r o n i cs 26 Use of a SPDT switch SPDT: Single pole double throw Power E l e ct r o n i cs 27 The switch changes the dc voltage level Power E l e ct r o n i cs 28 Addition of low pass filter Addition of (ideally lossless) L-C low-pass filter, for removal of switching harmonics: Choose filter cutoff frequency f0 much smaller than switching frequency fs This circuit is known as the “buck converter” Power E l e ct r o n i cs 29 Addition of control system for regulation of output voltage Power E l e ct r o n i cs 30 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 Power E l e ct r o n i cs 31 V. About this course Three parts of the content Relation with other courses Power electronics Fundamentals of analog / digital electronics Pre-requisite course Control systems for electric drives Continuing course Power electronic devices: Chapter 1 Power electronic circuits: Chapter 2, 3, 4, 5, 8 Control techniques: Chapter 6 and 7 Power E l e ct r o n i cs 32 Arrangement Text books  |x?? .uè ?è0/ ?v ??y<? ??y<?    Jai P. Agrawal. Power electronic systems : theory and design Beijing : Tsinghua University Presi , 2001 Lectures - 48 hours , all in English - After-class reading in Chinese and English will be assigned. Labs - 8 hours, 5 projects