What is Power electronics: Definition and 40 Discussions

Power electronics is the application of solid-state electronics to the control and conversion of electric power.
The first high power electronic devices were made using mercury-arc valves. In modern systems, the conversion is performed with semiconductor switching devices such as diodes, thyristors, and power transistors such as the power MOSFET and IGBT. In contrast to electronic systems concerned with transmission and processing of signals and data, in power electronics substantial amounts of electrical energy are processed. An AC/DC converter (rectifier) is the most typical power electronics device found in many consumer electronic devices, e.g. television sets, personal computers, battery chargers, etc. The power range is typically from tens of watts to several hundred watts. In industry, a common application is the variable speed drive (VSD) that is used to control an induction motor. The power range of VSDs start from a few hundred watts and end at tens of megawatts.
The power conversion systems can be classified according to the type of the input and output power

AC to DC (rectifier)
DC to AC (inverter)
DC to DC (DC-to-DC converter)
AC to AC (AC-to-AC converter)

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  1. S

    PhD student interested in control in power electronics

    Matlab/simulink provisional user
  2. P

    Engineering Small signal AC modeling for a boost converter with resistive losses

    I've attached my attempts at the solution and the actual question below. I believe the only issue I am having is I don't know how to get rid of "I" in both my final inductor and capacitor equations as the HW states I shouldn't have anything in term of I. I believe I need to put "I" in terms of...
  3. Boltzman Oscillation

    Engineering How should an H bridge circuit be analyzed?

    If I am given an H bridge circuit such as that below: How would I go on analyzing it? I would personally replace all of the transistors by their circuit models but then what would I do with the motor? Do I replace the motor with it's load resistance or is there more to it? I guess motors are...
  4. dvscrobe

    Engineering Reverse Current PMDC Motor Braking Using Power Electronics

    Summary: How do you determine the armature current during the braking time? For a simple permanent magnet DC motor with a known resistance and inductance in series with the armature, I would like to know how to determine the armature current if there was an electronic motor drive controlling...
  5. og_ogun_srvs

    Current or Power Reference Tracking with Power Electronics Converters

    Hi. This is my first post. Thanks to all who give it a look. I am working on an application that has very stringent power output requirements. There is a rechargeable battery that I am trying to manage through a bi-directional boost/buck converter as is typical of many modern-day electric...
  6. J

    Power Electronics: Choppers RLE Load

    Homework Statement Homework Equations I rms for triangular waveform = I(max)/ (1.732) R = V/I The Attempt at a Solution Since there is RLE load, current waveform is triangular. It is Source current is Average of I source. I used integration. Assumed Time period = 10 seconds. So T on = 5...
  7. J

    Power Electronics controlled rectifier solved example

    Homework Statement Homework Equations Solved example The Attempt at a Solution I think the red part should be (alpha/firing angle) = 180 - 45 Here since the angle is 45, it makes no difference if you do 90 + 45 or 180 - 45, but i think it should be 180 - 45. Am I right?
  8. J

    Power Electronics Rectifier Firing Angle and Overlap Angle

    Homework Statement Homework Equations Since question says the current is always continous, so overlap is always there. So option B is incorrect. Also since firing angle is increased from 0 to 45, the overlap angle will reduce. So it'll be less than 45. So option A is incorrect. The Attempt...
  9. S

    Why is chaos more studied in dc-dc converters compared to other circuits?

    Why is chaos only more studied in dc-dc converters and not in other nonlinear circuits, such as, rectifiers?
  10. thegreengineer

    Need help with voltage regulator circuit that uses 7805

    Well let me explain. I've finished a circuit that consists in a microcontroller unit (in this case a PIC16F877A) that is connected to a LCD module, a keyboard and a RTC module (via I2C protocol). As far as I know all of them require VCC (=+5V) for operating so I needed to create a +5V regulated...
  11. ESMAT 1995

    Constant current source Inverter

    i was reading about CSI and the first paragaph said "A constant current source is assumed here, which may be realized by using an inductance of suitable value, which must be high, in series with the current limited dc voltage source. " and it says nothing else about it , so clearly it's a basic...
  12. G

    Any advice for a power electronics newbie?

    I realize there are a lot of people on this forums in a related field of study. Was wondering if there was something you wish you would have done at/from the start of your career? I am graduate student in the field and am about to start an internship soon. Was wondering if there was anything I...
  13. V

    Power Electronics / Power Systems Textbook?

    Anyone know any good power electronics / power systems textbooks?
  14. Captain1024

    Why Might D2 Exceed 1 in DCM for Buck-Boost Converters?

    Homework Statement Image Link Homework Equations Switching Frequency ##f_s=\frac{1}{T_s}## ##K=\frac{2L}{RT_s}##, ##K_{CR}=(D')^2## ##R=\frac{V_o^2}{P_L}## In CCM: ##D'=(1-D)##, ##D'=\frac{-DV_{IN}}{V_O}## In DCM: ##D_2=\sqrt{K}##, ##\frac{V_O}{V_{IN}}=\frac{-D_1D_2R}{2Lf_s}## The Attempt at...
  15. V

    Electronics Power Electronics Book with DIY Projects

    I am a recent Electrical Engineering grad specializing in Power Systems. Are there any books with DIY projects relating to Power Electronics? I would like to do some projects that I will be able to put on my resume so employers will see that I have hands-on experience.
  16. Captain1024

    SEPIC Converter Analysis: CCM Operation with VL1, VL2, IC1, and IC2 Expressions

    Homework Statement Find expressions for VL1, VL2, IC1, IC2 for each of the two intervals of a SEPIC converter under CCM operation. link: http://i.imgur.com/EY98QbC.png Homework EquationsThe Attempt at a Solution link: http://i.imgur.com/SskXRoC.jpg?1
  17. Captain1024

    Efficiency of Buck-Boost Converter

    Homework Statement Consider a Buck-Boost converter. If in addition to the transistor on resistance (R_{ON}), the converter diode has a voltage drop (V_{D_0}), symbolically derive an expression for the efficiency, η of the converter, where η = 100* PO/PIN. Verify that that when R_{ON} and...
  18. srinaath

    Dynamic model of non-linear system

    i am finding it difficult to get insight about modelling of non linear system (electrical). my queries are, consider the system is DC DC converter... 1) I read that to study the dynamics of the system we linearise the non-linear system...why do we want to linearise it?... 2)can some one please...
  19. D

    Design of a Lightweight Waterproof (IP 67/68) Winch

    Hello, I am currently designing a lightweight waterproof winch system using off the shelf electrical or hand winches. My problem is that most electric winches that are waterproof are too heavy (design weight limit ~10lbs) and have a much higher force rating than needed (design max force ~500...
  20. J

    Subharmonic noise in DC-AC H-bridge Inverter

    I have a design for a DC-AC full H-bridge inverter implemented with IGBTs that is functioning quite well, but there is one problem that I am having trouble solving. I am seeing spikes in the FFT of the output noise floor that appear to be subharmonics of the PWM frequency. I am measuring the...
  21. ernd59

    Power electronics : half bridge vs H bridge

    what is the the Difference between the a H bridge and half bridge power inverter? i mean both do the same job ? what are the pro and contra of using a half/H bridge ? and how would it effect the size of a transformer if I am using one thanks
  22. nunuwishnu

    What is the step for designing a 3 Phase Inverter?

    I have troubles for designing a 3 phase inverter, and I cannot find the formula everywhere...
  23. Guidestone

    Opto TRIAC in power electronics -- where should I start?

    Hey guys. I'm not supposed to ask about homework stuff in this forums but I'll give it a shot cause I'm really really lost in this. Also, I won't be so specific. I'm taking the power electronics course from college and I'm supposed to give a presentation on Opto triacs. I just don't know where...
  24. H

    How to set the frequency of a switch in NI Multisim software

    I am a new user of Multisim and I am trying to make a buck converter. In other softwares, such as pspice I was able to control the switching frequency by editing properties but in Multisim, most of the switches are user interactive. I want to set frequency of 50 Hz in a switch. Kindly help me...
  25. smruti

    Power Electronics: Why Semiconductor Devices Operate as Switches

    Why only semiconductor devices in Power electronic circuits will operate as switches?
  26. Simon Hauser

    Very tricky Solar-Module Disconnecting Problem

    My non-ee boss gave me a design assignment I'm not sure is physically possible. I work at a solar panel manufacturing company. He wants me to essentially add a device to the mc4 connectors between modules which would allow disconnecting each module in a string from one another. He wants this...
  27. U

    Twin 120v breakout from 240v receptacle

    Hello, I live in the United States, I have an unused 20 amp 240v outlet that has two hot legs of 120v and a ground. Id like to make use of this outlet to create two 120 v outlets. I cannot access the main breaker of this panel, and am wondering if I were to make a plug with two female leads...
  28. N

    Engineering Effect of Cell on circuit half-wave rectifier circuit waveforms

    Homework Statement a) http://i.imgur.com/LrWxrEX.jpg b) http://i.imgur.com/3YmN3Rv.jpg Homework Equations A halt-wave rectifier(a) is used to charge a battery E.The battery is rated at 12V 100Wh. Average charging current for the battery should be 5A.The primary input voltage is 120v at 60Hz...
  29. Chacabucogod

    How Do Boost and Buck Converters Work in a DC-AC Inverter?

    I'm currently reading a paper given to me by my professor to expose to class. The problem is that I don't understand it very well! I'd like to see if you guys can help me. The paper I'm reading is "A boost dc-ac converter: Analysis, design, and experimentation" I've found the paper on the...
  30. H

    Bipolar and unipolar voltages and their significance

    Hello all! I'd like to clarify on the the differences of bipolar and unipolar voltages. I do understand that they both are used to trigger a number of semiconductor devices. Please and thank you!
  31. S

    Power Electronics; full-bridge inverter

    Homework Statement I have three problems of the same type that I am wanting to tackle in the next 3 days, so I was hoping that I could get verification here that I am indeed getting the correct answers. I have my final exam coming up, and the section on these questions does not have any...
  32. T

    Power Electronics Modules and Vendors - Help Needed

    Dear all, I have an urgent task of finding the right experimental modules for Power Electronics Course in my university, for undergrad. level. Could you please provide me with a list of good and reliable vendors who can provide me with modules that can enable the students to perform...
  33. Z

    What is the importance of power electronics in mechatronics engineering?

    I'm an mechatronics engineer student. My university offers Power Electronics course. However, it's not compulsory. As a student not very interested in capacitor, diode, inductor and complex things like that in a circuit design, I'm kinda on the fence about taking that course. I'm kinda much...
  34. J

    Power Electronics, transistors

    Hi, I'd need some help regarding some parts of an exercise (attached below). The question is that they make me assume that the tranistors is working as a chopper, so then I have many things to calculate. The question is, which kind of chopper should I assume? Thanks in advance...
  35. R

    A challenging power electronics question involving generators and transformers?

    Homework Statement A 3-phase, 10KV, busbar of a power station is divided into three sections joined by two reactors as shown in Figure 1. Each section contains a synchronous generator and supplies a transmission line through a transformer. The parameters of genera-tors, reactors and...
  36. V

    Electric machines & power electronics - PMAC machine connected in Y, 4 poles

    Homework Statement A PMAC machine is connected in Y and has 4 poles. I_F\,=\,27\,A and L_m\,=\,20\,mH. a) It is to operate at a torque of 35 Nm and at a speed of 4000 RPM. Calculate the necessary stator current I_S and voltage V_{S\,line-to-line} so that the losses are minimal. b) If the...
  37. V

    Engineering Electrical Machines and Power Electronics - 3 phase, 6 pole induction motor

    Homework Statement A three phase, 6-pole, \Delta connected induction motor is rated 208V, 60Hz. It has R_R\,=\,5.2\,\Omega, R_S\,=\,2.2\,\Omega, X_m\,=\,220\,\Omega, X_{lr}\,=\,7.5\,\Omega, X_{ls}\,=\,2.3\,\Omega. Calculate the starting torque and both phase and line currents when the motor...
  38. A

    Good texts on power electronics and power systems

    Could anyone suggest me good books on power electronics,power systems and calculus?I belong to Electrical and electronics department.
  39. C

    EE Engineering Major: Micro-electronics or Power Electronics?

    Hi, I am doing EEE at Adelaide University in Australia. I want to major in Micro-electronics. But all of my friends say it is better to major in Power Electronics as the mining industry is booming all over the world. Apparently it looks easier to get a job in mining. But i want to major in...
  40. V

    Where Can I Find Reliable Learning Material for Power Electronics?

    somebody suggest me some good learning material for power electronics