Questions tagged [power-electronics]

Refers to the conversion of electric power by using solid state components such as semiconductors. Can also generally apply to the field of electrical engineering which works with power electronics.

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Reversible Constant Current Source (CCS)

I need a current source, that can work in both directions. To make it simple, I need to generate a square signal in current. I am currently using a simple H-bridge, but without any current regulation. ...
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7answers
873 views

Role of Electrolytic Capacitors and whether they can be replaced by Film capacitors in battery operated power converters

In battery operated power converters such as motor controller ( half bridge or full bridge ) bulk capacitance is placed across Vdd and Gnd . I thought this was unnecessary since the input is DC and ...
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210 views

Fuse symbol on toroidal transformer

I was searching today for a new 24V transformer, and I found that some of them have a "fuse" symbol on their label, and I was wondering what this fuse symbol means? Does the fuse symbol on a ...
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14k views

Average output voltage of a fully controlled full wave rectifier

What is the average voltage for a fully controlled bridge rectifier with firing angle \$\alpha\$ ? In a lot of web resources it is said to be: $$\frac{V_{max}}{\pi} (1+ cos(\alpha))$$ For example ...
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Voltage Spikes in MOSFET H Bridge

As a part of my effort to build a pure sine inverter I made the following MOSFET H Bridge. This was connected to a load through a LC filter where PWM signals are given as in the diagram below.PWM ...
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1k views

Air gap in switching power supply transformer

An article I have read regarding switching power supplies (http://sound.whsites.net/articles/smps-primer.html) says that push-pull, half-bridge, and full-bridge switching supplies don't use an air gap ...
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71 views

BJT configuration

For the three basic common BJT amplifiers, Common Emitter, Common Base, Common Collector. How do you differentiate them? I was told that the term "common" because the particular leg is the common ...
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4k views

How can I size the DC link capacitor of a 3 phase inverter?

I have come across the Salcone-Bond paper Selecting Film Bus Link Capacitors For High Performance Inverter Applications (PDF), which shows equations for single-phase inverters. But I can't seem to ...
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603 views

Using pulsed power source and capacitors for driving solenoids

I'm converting a reed organ to be MIDI controlled, and I'm using solenoids to pull down on the keys. There's 88 solenoids total, and I'm going to be powering it with 2x 40A 12V power supplies. The ...
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1answer
56 views

Brake Resistor in Regenerative Case for Elevator

I am trying to understand the switching pattern of Inverter and the Brake chopper while a 3-phase AC motor is in regenerative mode for example in Elevator case: When its Cabin is full and it is ...
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4answers
181 views

Phasor vs Vector vs Space Vector

I wonder what is the difference between a Phasor, a Vector and a Space Vector? A phasor is also a rotating vector in space then it means that a space vector is same as a phasor? Also by definition a ...
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100 views

Electronic Element

Does anyone know what is the mentioned element in the picture? and also what is the purpose of that (it is R2 in schematic picture)? Also there is C28 in schematic picture, what is the purpose of that?...
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1k views

increase current of a microcontroller output

Edit: The motor consumes 130 mA, I have tried the ULN2803A and the L2930DNE, but there is no way to make this work.. I thought this question would be already asked, but I have used the search tool ...
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1answer
95 views

Problem while simulating EMI Filter for power lines

I was designing an EMI Filter for the CE102 standard. I was a bit confused on how to provide noise source to the circuit, since (as of my knowledge) EMI noise enters our system by parasitic ...
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1answer
268 views

Difference between a 3 phase VFD inverter and UPS inverter

this might seem like an odd question, but i consider myself still a newbie in Power electronics. This has been circling in my head for a few days. Intro : From a Hardware Standpoint i am assuming ...
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1answer
449 views

Power categories in ASIC design (Design Compiler)

I am currently working on the synthesis, with Synopsys' Design Compiler, of an AES encryption module. In the power reports there are three power categories specified : Switching Power Internal Power ...
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2answers
412 views

Where should I look for transformer inductance discrepancy?

I'm experimenting with this smallish (~15VA) toroidal line transformer as a "lab" exercise as I'm learning about transformers. Right now it has its original 115V primary winding only; I "unwound" and ...
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1answer
4k views

Brushed DC motor control MOSFET selection

I want to control a brushed DC motor of the below specification: Motor: Permanent magnet DC brushed motor Voltage: 180V Current: 5 Amps RPM: 1500 The control method is PWM switching through a ...
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1answer
99 views

Flyback discontinuous mode, double voltage over the switch

Considering the following simplified flyback schematic. Which has the following voltage current graphs Why is there 2*Vin over the switch when the switch is turned off? And why is that change to Vin ...
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1answer
322 views

AC MOSFET switching without any diodes? [Low-Cost AC Solid-State Relay With MOSFETs]

Is it possible to switch an AC load using two MOSFETs in anti-series such as the picture below? In this mode, each MOSFET is on during one half of the wave and the other's body diode conducts to ...
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1answer
76 views

What is the meaning of this statement “If any diode has fully recovered before the V across it starts to swing, there is no reverse recovery current”?

Here is an excerpt from the book 'A-Z Switching power supplies' by Sanjay Maniktla. "To minimize EMI, ultrafast diodes should be selected on the basis of softer reverse recovery characteristics. For ...
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1answer
439 views

energy density comparison between inductors and capacitors

The figure below is about energy density comparison between inductors and capacitors. This thesis concludes that capacitors possess greater energy density than inductors, as seen in the figure. ...
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547 views

Loop gain calculation for the buck converter

The figure below is small signal model for buck converter from Switch-Mode Power Supplies Spice Simulations and Practical Designs by Christophe Basso. Could anyone explain why the loop gain is 12000 ...
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1answer
72 views

Solid-state lighting [closed]

Background Consider the following technologies: 100 lm/W OLED (2008, source) 303 lm/W LED (2014, source) 94 lm/W LEP (2015, source) For growing food, the preferred measurement is Photosynthetically ...
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1answer
2k views

Open loop PWM using TL494

I need to generate a fixed frequency and variable duty cycle PWM signal. Normally I would've used a microcontroller , but due to unavoidable circumstances , I have to use the TL494. I did an extensive ...
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1answer
416 views

What does “mod 2” mean in these multi-level inverter switching equations?

I am working through a paper that discusses the design of a multi-level inverter to connect photovoltaic arrays to the grid. It uses 4 PV modules (only two are shown in the design image below, but it ...
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3answers
2k views

How do Wi-Fi controlled light switches feed themselves?

There are smart light switches in the market that are Wi-Fi controlled like Plumlife (formerly ube) and Belkin WeMo. I wonder how they control the electricity that they operate on. When I unplug my ...
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1answer
1k views

How to limit current of an AC signal

For my project, I'm trying to work with the principle of electrovibration. This principle is about simulating textures using low current electricity on an insulated conductive surface (see Wikipedia). ...
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1answer
727 views

Buck Converter with resistive load

I was reading a chapter on Step down Choppers(Buck Converters). I had trouble understanding the operation of the circuit as it wasn't explained properly in the book. When I looked up on the internet , ...
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1answer
221 views

What could cause the mosfet to burn out in my motor driver?

Here's the schematic: I've tried to make this motor driver as tough as possible, but I'm still seeing occasional failures where the MOSFET and the diode D1 are both failed short. Any ideas what ...
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1answer
208 views

Attaching temperature sensors to solar cells

For my project, I have to find the temperature coefficients of the solar module that I am using. Meaning that I need to calculate the change in voltage, current and power with respect to temperature ...
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1answer
329 views

Zener problem in motion detection circuit

I am studying a sample motion detection circuit which uses a D203S PIR sensor and a BISS0001 motion detector IC. After sensing motion, BISS0001 gives output which switches SCR and SCR switches TRIAC. ...
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1answer
160 views

Using Power Good pins for sequencing

I'm trying to figure out a way to use the Power Good outputs of several stages of voltage regulators to sequence and monitor a board powering several FPGAs. I've done this easily before with a ...
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2answers
4k views

How to reduce noise causing by MOSFET driver?

I am trying to get +/- 12V and +/- 5V voltage in my board. I am getting lot of noise on the primary side itself as well it is carrying to the secondary side. I am driving the MOSFET with 100KHz PWM ...
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1answer
728 views

How to generate a short (µs) high power pulse

I'm faced with the following problem. I would like to send a current pulse of about one amp through tissue with a resistance of about 3000 ohm (so I need 3000 V obviously). The pulse should be as ...
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30 views

MOSFET pinchoff reduce current

I understand that in an n channel MOSFET as Vgs increases, electrons are attracted towards the gate forming an n channel. These electrons are responsible for the conduction of the MOSFET. As Vds ...
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56 views

Alternate uses for Gate Driver - Driving a Load without External IGBT or FET

What issues would one encounter by using a gate driver IC to directly drive a load instead of using it to drive transistors? For consideration would be the very affordable Infineon 2EDN752x series ...
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267 views

Why do I get high DC current in grid tied inverter output?

Edit: Added gating signal waveforms. Changed some of the graphs, I accidentally put a test circuit waveforms the first time. Current is not that high but offset is there and current is high for a ...
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1answer
290 views

How does three phase full converter work?

My question is for firing angle(alpha)=0,why is T1 triggered at 30?
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1answer
64 views

Generating a current with ionized water droplets (in a cloud)

Playing mind games with myself tonight; I know some of the windiest spots in the world are at the tops of mountains and often socked in the clouds. To measure meteorological phenomena at these ...
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1answer
5k views

Calculation of diode switching losses

I am an Electrical Engineering student. I'm in my final year and doing a thesis about soft switching. I am trying to grasp the calculation of diode switching losses. I'm having the impression that ...
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3answers
149 views

Auxiliary circuit to reduce power losses in idle stage of this oscillator (wireless power application)

I am trying to implement the following resonant oscillator for wireless power transfer application. There will be a secondary coil coupled with Lp. . Reference - WPT Application Note One of the ...
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1answer
317 views

Why would someone prefer halfwave rectifier over bridge rectifier? [duplicate]

The other day, out of curiosity I was measuring the current wave shape of a laptop charger. The wave shape indicated a spike only in one half cycle. I'm guessing half wave rectifier here. One thing ...
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2answers
396 views

Why is gallium nitride used in power electronics? Are there any alternatives available?

I'm preparing for a seminar related to variable gain amplifier. I read that GaN/AlGaN are used. I wish to know why they specifically use them.
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996 views

Why plug is polarized in the US? What are the benefits?

I could not get a good hold of it, I searched online quite a bit. This must have to do with safety but then non-polarized switches are used through out the world with no issues are risks, so my ...
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2answers
1k views

MOSFET body diode conduction

Does the body diode in MOSFET conduct current in backward direction when the MOSFET is switched OFF? If yes, can we build rectifier-bridge using 4 non-driven MOSFETs?
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2answers
486 views

Mechanical Switch in parallel to the Micro Controller working in Sync

Here is the image for my requirement,want to operate Load Lamp of 230V AC with Mechanical Switch in parallel to Controller where one can 'ON' the Load Lamp from the Mechanical Switch and 'OFF' from ...
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2answers
159 views

Meanings of some symbols in electronics

I am new to electronics and i want to get about what do the symbols encircled in red signify? Can anyone tell me what is happening in the diagram. Please help me. Regards .png
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SMPS: What is current mode instability (aka “sub-harmonic oscillation”)?

In peak current controlled switching power supplies, there is a phenomenon called “current mode instability” aka “sub-harmonic oscillation”. What is that? Can't seem to get a good explanation of this.....
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Working and simple applications of PLL [closed]

Recently I am studying about Phase Locked Loop. My professor said that it is an amazing device with a variety of application. I understood the basic working of a PLL. But I couldn't appreciate his ...