# 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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442 views

### Learning transistor based circuits

simulate this circuit – Schematic created using CircuitLab In one of our electronic circuit tests, this question was asked: What is the output voltage of given circuit? This circuit looks ...
577 views

### Why is Junction Temperature called so?

Why is the silicon die temperature inside a semiconductor device referred to as "Junction" Temperature ? Though this name may make sense for minority carrier devices where there is maximum power ...
398 views

### Is the Nyquist plot useful in actual electrical engineering?

I am currently doing a course on linear control theory, and we are covering Nyquist Plot to study phase and gain margin. I find myself unable to appreciate this concept. One, the proof of the Nyquist ...
796 views

### Push current source through transfromer

This lecture (from page 130) shows manipulation of the buck-boost converter model into canonical form. I am stucked at moving current source through transformer as in the picture below or from the ...
1k views

### How does this FM transmitter work?

I'm an electronics student and I have been trying to understand this FM transmitter diagram (taken from electronicshub.org) for a long time. I had put efforts to learn it by surfing the web but parts ...
421 views

### DC current transmission loss vs. conversion loss

I'm going to transmit about 7 Watt DC over 4 meters long twisted pair Ethernet cable. I'm thinking of using Buck and Boost converters to step-up to 30 V and step-down to 5 V the voltage before and ...
4k views

### Run heater on two powerlines, where the second line is switched according to the main line

I got a water heater which is rated 6kW. The "heating element" consists of 3 heating elements that are connected in series for 1-phase usage. I would like to run two of those heating elements on one ...
411 views

### Ripple current in synchronous buck converter

I am designing a synchronous buck converter and I am at the bread board stage in my design. I wanted to check the current waveform through the inductor, but I do not have a current probe available. I ...
418 views

### 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. ...
883 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 ...
229 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 ...
15k 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 ...
2k views

### 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 ...
1k views

### Air gap in switching power supply transformer

An article I have read regarding switching power supplies (https://sound-au.com/articles/smps-primer.html) says that push-pull, half-bridge, and full-bridge switching supplies don't use an air gap in ...
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 ...
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 ...
660 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 ...
100 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 ...
231 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 ...
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?...
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 ...
99 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 ...
274 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 ...
472 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 ...
416 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 ...
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 ...
54 views

### Voltage Regulation to Brushless DC Motor

I am using a 12V brushless DC motor (peak current 4.6A) and I would like to have speed control over it. Link to pump I am using: https://daviescraig.com.au/product/ebp40-electric-booster-pump-12v-...
107 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 ...
387 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 ...
79 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 ...
458 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. ...
564 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 ...
73 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 ...
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 ...
425 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 ...
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 ...
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). ...
733 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 , ...
269 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 ...
219 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 ...
338 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. ...
168 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 ...
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 ...
742 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 ...
31 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 ...
58 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 ...
275 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 ...
294 views

### How does three phase full converter work?

My question is for firing angle(alpha)=0,why is T1 triggered at 30?
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 ...
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 ...