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.

275 questions with no upvoted or accepted answers
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1answer
335 views

Safety Capacitor Selection

When selecting an X2 safety capacitor what must be taken into consideration. There are only a few types of capacitance ranges and seem to be chosen based on voltage rather than capacitance. Take ...
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3answers
1k views

Calculating the ESR of Capacitor

I try to calculate the ESR of a capacitor. I checked this datasheet: http://www.farnell.com/datasheets/2245214.pdf?_ga=2.167304311.817060034.1534770853-676261198.1531404202 I can see from the ...
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2answers
52 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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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 ...
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2answers
292 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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2answers
102 views

Voltage doubler and power

Lets consider for instance this voltage doubler: It was told that a practical limit of this circuit is the fact that we cannot absorb too much current from it. But I wanted to verify (if it is true) ...
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0answers
49 views

Can a Capacitance Multiplier be used with high voltage outputs?

I am designing an SMPS which two output voltages of 5kV and 2.5kV. My transformer is split into four equal sections, each feeding a FB multiplier, connected in series to form the final voltages. ...
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0answers
70 views

Bipolar transistors that only connect via base to emitter

I am trying to understand how to use this configuration of the LTC2992 power measure IC and the only part I am confused with so far is the two transistors which I have circled. What I know so far ...
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2answers
107 views

Protect Inverter from Transformer's Inrush Current

Consider a "small" autonomous grid, which is based mainly on RES and has a few diesel generators, like in the following figure Everything runs smoothly, feeding the small load. Suddenly, the big ...
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0answers
57 views

How does a electropermanent magnet work?

I’m trying to wrap my head around electropermanent magnetism. I read this wonderful PhD Thesis by Ara Knaian as well as details the history of this concept as well as Kyle Gilpin, Ara Knaian, and ...
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1answer
546 views

Fourier Series Expansion of the phase current of a three phase full wave bridge rectifier

I am really struggling with this homework problem where I am asked to calculate the harmonic components as a ratio of the first fundamental harmonic of the phase current of a three phase rectifier ...
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83 views

High frequency switching applications

I was reading that for high frequency switching applications with semiconductors, the ratio of the electron to hole mobility should be high. Why is it so? Is it a necessary condition always? Or ...
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1answer
142 views

Placement of feedback line on DC DC converter, before or after cap? (and dropout problem with LT8390)

I am using an LT8390 DC to DC converter, I have a highly inductive load and it is causing dips. The dips are shown here (and about a 6V drop for 7ms): I need to get rid of the dips, which I will ...
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61 views

How does a MOSFET conduct in saturation region?

It is a simple question but I could not find a straightforward answer. When a MOSFET enters saturation region, the channel length starts to decrease, and the channel width is the smallest near the ...
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1answer
167 views

Why does a turbine with PMSG and full converter system draws reactive power when turbine is stopped or there is no wind?

Our turbine has a permanent magnet synchronous generator and full converter system (rectifier diods for rectification and IGBTs for chopping dc link voltage and as inverters) which means its generator ...
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3answers
239 views

How to determine forward voltage for overdriven LEDs

I'm trying to figure out how to determine the forward voltage and forward current for overdriven LEDs, and need a bit of help understanding what are the dependent variables and which are independent ...
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291 views

Ceramic capacitor in High voltage DC link

In motor drive application the high voltage dc link between the rectifier and the inverter usually have: a bank of aluminium electrolytic capacitor a film capacitor near the inverter Is there a ...
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1answer
947 views

How can I calculate the base current of a transistor to get a specific emitter-collector voltage?

For this circuit I am asked to calculate how much base current I need to supply to the transistor to get a Vce = 220.745 mV. The thing that has me stuck in this is that the problem does not provide me ...
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1answer
254 views

How to connect four different ground planes in the same PCB?

I am working on a project which uses the LTC4020 multi-chemistry battery charger from Linear Technology. The design includes a microcontroller ( NXP KL25Z) to provide additional outputs and ...
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1answer
1k views

Designing a DC 12V 80A Power Distribution PCB panel and heat sinking

Background I'm trying to build a small hobby grade ROV for an underwater robotics competition held at the university I'm studying. And I have used eight brushed dc motors each of which consumes 8A on ...
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23 views

Charge and power distribution circuit with multiple batteries

I’m looking for solution for electric vehicle charge and power distribution system PCB. For some reasons I want to split battery to several Li-Ion packs in separated units (hulls). I see the next ...
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2answers
41 views

AD8318 Maximum Input Voltage

let's consider AD8318, a chip which contains a logarithmic amplifier, often used for power measurements. I have read its datasheet and there is a thing that I do not understand: no maximum input RF ...
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42 views

Current Transformer Rated primary current vs Max. Primary current

I've been reading up alot on how to work with a CT. Basicly you have a primary current (eg: 100A) and a turns ratio (eg:1:2500) and a load resistance (eg:5 ohms) so now things are straight forward we ...
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46 views

MP1584 5v regulator voltage drop problem

I was debugging the MP1584 module, 5v regulator circuit in the PCB. I have attached my debug circuit below. I have completed my circuit in breadboard and PCB also, but I was connected to any load ...
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1answer
57 views

What is the effect of doubling the airgap in a flyback converter?

If I understand correctly it would flatten the hysteresis curve. So it would allow to store more energy and it would also decrease the permeability of the core. Would it have another effect or will ...
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37 views

Planar Transformer Design and Insulation Requirements

I am currently thinking of designing a planar transformer for my SMPS application. The input voltage will be somewhere in the region of 150V, the output voltage in the region of 1.5kV. First of all, ...
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0answers
19 views

Fixed Frequency Control of Multi-Resonant Converters

I am currently designing a SMPS based on the half-bridge LCC converter. Due to my application, it is desired to operate the converter at a fixed frequency. I also wish to optimize the passive ...
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1answer
44 views

By pass diode in PV cells

hope you all are well The bypass diode is usually connected in parallel with PV cell to avoid hot spot and prevent more PV output power losses. The bypass diode is connected in opposite direction to ...
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4answers
70 views

Momentary Over-Excitation Voltage Circuit

I want to control an electromagnetic brake (fail-safe brake) used along with servo motor. Microcontroller will control the trigger signal for the electromagnet coil. Electromagnet Requirements: ...
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0answers
95 views

Can I use diodes to protect power supply outputs?

(Note, this is my first question on this site, please point out if there is something that I am doing wrong here.) I have a thyratron that requires two separate power lines to attach to it. The two ...
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19 views

Heat transfer coefficient in a Module Baseplate

Today, for example in a power IGBT module cooled by a heatsink, it has been found that the heat transfer coefficient (htc) distribution may not be uniform across the bottom surface of the module ...
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2answers
37 views

Transistors' Scattering Parameters

I have some doubts about the Scattering Matrix of a transistor seen as a 3 port devices. Precisely, I read (for instance here) that we do not have 9 independent S parameters since there is this ...
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1answer
81 views

Transformer to convert 220V split phase to 220V single phase

I'm a digital guy whose forgotten his "big wire" electrical education. I'm surprisingly unable to find a solid reference for this. I have a (European) 220V 50Hz split phase source (110V + 110V + GND)....
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3answers
51 views

Microstrip propagation mode

I have a trivial question about EM propagation in a microstrip line. Why do the electric and magnetic fields have the following lines? Which are the physical laws (Maxwell etc) for determining them? ...
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0answers
36 views

How to choose a DC-DC Converter for a motor with inrush current? (Theory)

I am wondering how to choose a DC-DC converter for a motor. This is a theoretical question for understanding. For example, if I have a converter that can output 5V with a maximum current of 1A. ...
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0answers
54 views

What component is best for a voltage follower amp (specs given in question)?

I am wanting an op amp that can act as a voltage follower. Essentially the project is speed control of a motor and since PWM is being used, the following circuit was going to be implemented: ...
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1answer
72 views

Amplifying Sinusoid From Microcontroller to ~40V 3-5A

I’m investigating transient switch arcing that occurs in a 3 phase switching unit. I am planning on generating the phase signals with an STM32F4 using DAC and DMA with timing separation for the phase ...
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1answer
35 views

Slip Control vs Constant V/F Control for 3-Phase ACIM

I am trying to understand how is Slip Control different from Constant V/F control. If I need to control the speed of 3-phase ACIM then its slip would obviously change with its rotational speed then ...
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0answers
31 views

What does 'Rectifier Loading Effect and Loading Factor' mean

I came across the terms 'Rectifier Loading Effect' and 'Rectifier Loading Factor' when reading IEEE Std 421.5-2005 Recommended Model for Power Stability Studies, mentioned in those ACxA models. What ...
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2answers
117 views

How do I connect an LED with floating DC voltage?

I want to connected an LED at the output of 500V DC. This DC power supply is made by 3phase DC rectifier and is floating. I would like to have a display on the front panel of the supply which will ...
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0answers
56 views

Cant recognise a Damaged component of switched-mode power supply

I was repairing an smps ATX power supply I found a damaged component that I could not it recognise. I thought it's a power switch since it was mounted to a heat sink along with tow D13007 NPN power ...
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0answers
47 views

Does potentiometer accuracy change with degree of movement?

I want to use a conductive plastic potentiometer for my actuator application where movement is +/- 40 degrees. As in datasheet, the potentiometer linearity is given as +/-0.2 % which I think is for ...
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0answers
22 views

Which power converter topology has higher benefit of EMI/EMC?

Which power converter topology can be best suited for EMC compliance for small power converter to be used in LED lighting products. In my context I'm using a 5W non-isolated AC-DC converter which is ...
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1answer
65 views

Heating issues with solar charging circuit

I am using the above circuit to charge a 7.4V Li-ion Battery.With input MPPT voltage set at 12V, I have applied 13V input voltage to the circuit. The battery is charging at 1.4A. (according to the ...
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0answers
99 views

2 Switch Forward Converter Volt-Sec/Charge Balance

I am attempting to design a 2 switch forward converter. I understand how to do the volt-sec balance and charge balance when the converter is as shown in the ideal 2 switch forward converter below. I ...
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0answers
85 views

SVPWM for BLDC Motors: Switching Losses vs Neutral Point Voltage Swing/fluctuation

I am implementing a SVPWM (Space Vector Pulse Width Modulation) scheme for a 3-phase inverter (3 H-bridges, nothing fancy) to control a BLDC Motor. Since one can choose which zero vectors (000 or 111)...
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0answers
86 views

Finding Width of MOSFET

We are struggling with part iv of the question above where we have to find the width of both MOSFETS. As you can see from our working out, we have found a width of 2 meters for the nMOS, which we know ...
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66 views

Discrepancy between simulation and measurement for a voltage doubler/ rectifier design at 5.8 GHz

I am designing a pretty straight-forward voltage doubler at 5.8 GHz with MACOM's MA4E1317 diode, which I have used before and know from previous experience that matches pretty well with the spice ...
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0answers
367 views

Overvoltage protection circuitry choice

I need to design a input overvoltage protection for a 45W DC-DC converter rated for a 9-24V wall wart input (so, 45W / 9V = 5A input current at max). So far I've seen two approaches (schematics below):...
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48 views

DC DC converter opamp compensation

I have simple doubt. I am making a closed loop DC DC converter flyback, I am using opamp for compensation. It should be a single input single output network. Input voltage is 24-32 volt, output is 5V ,...