# Questions tagged [power-factor-correction]

A circuit that compensates the reactive characteristics of a load to make behave as close as possible to a resistive load in order to maximize the power consumption efficiency.

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I'm interested in how the efficiency of a transformer changes with the power factor of the load. I know that in principle you can increase efficiency through power factor correction (i.e. making your ...
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### Can large power stations which are not running can be used for power factor improvement of national grid. How? [closed]

My friend told me that the large power stations which are not running can be used for power factor improvement of national grid. I wonder how it can be done? If true, can these stations charge for ...
1 vote
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### Why does the zcd square wave look distorted?

I have connected a capacitor to do some power factor correction on a load. After I connected the capacitor parallel to load, I checked the zero cross detection waveform, which is getting input signal ...
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### determining the Bmax for inductor design

at this moment of this youtube video following graph is presented for selecting the proper maximum flux density. the considered proper amount of core loss is 100mW/cm^3. is this a general amount for ...
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### Question regarding PF correction

Lets say I have load A with certain A wattage and PF A and load B with B wattage and PF B connect to a same voltage supply. Then i have questions below. a)Theoretically, there a resultant wattage and ...
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### Can VCC be supplied by external power supply?

I've implemented the following 80W PFC boost pre-regulator presented in the following application note. I built the inductor and its auxiliary winding myself with another magnetic core and its ...
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### Using fuse during initial tests?

I've implemented the presented 80W PFC boost pre-regulator in the following application note without using the applied fuse at the input. Surely I will add the fuse to the finalized tested circuit. ...
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### What the criteria of power factor correction capacitor?

I'm thinking of selecting a load with active power less than 200W and PF<0.5 for my school assignment to show the result of current usage before and after power factor correction. There are ...
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1 vote
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### Rectifier circuit behavior - Need an intuitive understanding

Case1: OUT Series res = 10 ohm -> spiky input current reaching upto 15 A -> capacitor charging fast After a long time: Case 2: OUT series res = 100 ohm -> almost sinusoidal input current ...
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1 vote
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### How critical is the sense resistor?

In the following topology, two 0.68 ohm resistors are paralleled to result in 0.34 ohm for sensing the source current. Can I use three paralleled 1 ohm resistors to result in 0.333 ohm? Does this ...
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### implementing dot convention

in the following topology, a boost inductor with secondary winding is operated in which the windings are in opposite directions. Implementing this structure, in reality, made me confused. Based on my ...
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### What is this component in a power supply?

We bought a Cisco 6500 series 6 kW PSU and took it apart. This is a module connected immediately to the inputs of the power supply unit. Does anyone know what it does?
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### Can I replace the ceramic capacitor with tantalum?

In the following topology, a 2200nF multilayer ceramic capacitor (SR305E225MAR) is used in the compensation network. Can I replace it with a tantalum capacitor with equivalent voltage and capacitance? ...
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### Please verify the proof for percentage of error in power factor measurement

I am constructing an ac wattmeter for my school project, one of the objective is to achieve discrepancy of result(power factor) that is within 5% as compare to the actual measurement result obtained ...
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1 vote
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### Power factor problem

I need help solving this problem in my mind, so if anyone had a similar problem it would help me. In order to make a higher power factor on a receiver, we connect a capacitor of appropriate capacity ...
1 vote
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### CCM Boost PFC avg rms current

I follow the "Fundamentals of Power Electronics-3rd Edition" to derive the below equation. Now, I would like to derive the Transistor Average, ， and I follow the book formula, but my answer ...
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### CCM boost PFC rms current ca;cu;ation

Does anyone know how to calculate the Boost PFC rms current. I read the "Fundamentals of Power Electronics", there is a formula but I can't total understand. 1.) How to get the red part ...
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### Active PFC with discrete components

First of all, I've had no formal training as an electrical engineer, I've taught myself everything I know online, so this may be a stupid question. That said, I've designed an active PFC circuit using ...
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### Boost PFC power loss calcaulation

I am studying boost PFC topologies. I run into a question, how to calculate the CCM / CRM /DCM boost PFC power loss. I read the On semi document. I would like to derive the Diodes RMS current, but I ...
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### DC leakage in single and three-phase rectifier (Electric vehicle chargers)

It seems that the IEC 61851-1 standard ask for a device monitoring DC earth current for any EV charging station, either single or three phases. What I'm wondering, is, which topology of charger, or ...
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### Power factor of a synchronous based DER

I am working on a project including a synchronous based DER (2 Gens).I have a few question, I'll appreciate if you could help me. 1- I want to see what would be the typical control-mode setting of the ...
1 vote
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### Is there any advantage if the PFC inductor is split in between +ve and -ve input line?

While doing the reverse engineering this is what I observed. The PFC inductor is having 8 set of pins , out of which 4 are shorted to input (+) and 4 are shorted to GND (input return). Obviously , ...
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### Bigger NTC = better protection?

A 2.5 ohm NTC is used in the following PFC booster. I've got a 20 ohm one. Can I use it instead of 2.5ohm one? Does it provide better protection or does it disturb the normal operation of the circuit?
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1 vote
127 views

### Why did the CS resistor explode in this circuit?

I implemented the following PFC boost converter as shown in the second image and plugged it into 220V with the no-load condition but it exploded at the plug-in. The explosion happened in the sense ...
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### Is there any problem to test the following topology without load?

I've implemented the following PFC boost 80W converter. Is there any problem to test the following topology without load?
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### EMI analysis for low power low voltage AC/DC

I've designed an 80W 220V-IN 400V-OUT PFC Boost converter in order to analyze its conductive EMI and design the proper active EMI filter for it. but as this is my first implementation project, working ...
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1 vote
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### How does a Vienna rectifier try to make its input current sinusoidal to reduce THD? [closed]

I cannot seem to figure out the working of the three phase Vienna rectifier for power factor correction. How do the various switching states cause the input current to be sinusoidal?
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### Power factor calculation for 3 phase IM using current and voltage measurement

How to calculate power factor for a 3 phase IM with delta connection ? I can measure line current waveform and phase voltages (between each conductor and a common reference) for all three phases. ...
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### Can I use MKT capacitor instead of MKP in the following topology?

The following topology is a boost PFC designed by STMicroelectronics. The input capacitor (C1) is an MKP one. Can I use an MKT (fig2) or polyester (fig3) capacitor instead of that?
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### What could be the reason for using line frequency toroidal transformers at the input of a power supply board (with PFC)?

During the teardown of a power supply board, we found a bulky toroidal transformer (similar to image below) at the ac input line (voltage 115V AC). The secondary of transformer is subsequently ...
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### Question regarding connecting LISN to a three phase PFC

I am trying to connect a Line Impedance Stabilisation Network (LISN) to a three-phase PFC rectifier simulation model as I want to simulate the common-mode and differential mode EMI. Most references on ...
1 vote
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### What is the purpose of this block in UC2854 based PFC circuits?

Below is a snippet from the datasheet of UC2854. Current transformer senses the input current of PFC. But Rs also does the same. What is the square block shown here?
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### Phase of grid current is not varying in the simple RL circuit

I am trying to implement the following circuit: Circuit parameters are as follows: R1 = 2 ohms L1 = 10mH V_inverter = 28.175V (peak) V_grid = 200V (peak) I want the grid current to vary in full ...
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### Options for current sensing for a 230V , 100 W boost PFC circuit?

So I have the following boost PFC circuit: I wish to sense the inductor current. My first thought was using shunt with instrumentation amplifiers, but the issue is total voltage across the inductor ...
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### Active PFC design and simulation with reactive loads

While designing the building blocks of a double conversion pure sine wave inverter designed for standby generators, and specifically the AC to 400V DC conversion required to feed the pure sine wave ...
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### Boost PFC converter stepping up voltage but unable to shape the input current

So, I have designed the following boost PFC circuit in simulink: This is the DC output voltage: But this is the input current: I am trying to tune the PI control but nothing works out. The PI ...
1 vote
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### How does the RL series circuit model the effect of load/backemf in an induction motor?

I know how induction motor works: The rotor produces maximum backemf on no load and keeps the current to minimum. On load, the backemf reduces and the rotor draws more current. In power factor ...
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### How can I accurately and quickly simulate this 280Ah battery charger circuit with a real-time charging time of over 2 hour?

So I am designing an on-board charger of rating 10kW in MATLAB simulink for an electric vehicle to charge a 72V, 280Ah battery with a maximum charging current of 125A. As the calculations work out, it ...
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### What happens when you feed DC instead of AC power into an SMPS with PFC?

I was reading about topologies used in power factor correction like: Boost FPC bridgeless-boost PFC Totem-pole bridgeless-boost PFC I was wondering what would happen in each of the mentioned PFC ...
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### Which frequency should be considered for inductor design in this FOT (fixed on time) PFC?

The PFC topology, I'm trying to design, works in transition mode, and switching frequency varies from 37 kHz to about 600 kHz according to the phase. The current flow through the inductor is as ...
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### Configuring a 2:1 stepdown transformer for efficient "solar charging" of an EV from a small PV array

What is the best way to configure a isolating 2:1 stepdown transformer, so that an EV can be efficiently charged (using a mode-2 EVSE which has a built-in RCD/GFI) without drawing more than 1 kW from ...
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### Need help with simulation of three-phase rectifier with hysteresis controller

I am attempting to design a closed loop three-phase rectifier with hysteresis control using MATLAB simulink. The outer loop compares output DC voltage with reference voltage, given to a PI controller ...
1 vote
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### PFC voltage loop bandwidth

I have two questions about PFC control problem. 1.) For PFC application, the current loop bandwidth needs to be high. But I don't understand why voltage loop bandwidth needs to be slow. What's the ...
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### Input Boost Low-Harmonic Rectifier

I have a question from Coursera, Please see the below figure. I don't understand what does question 13 means, could someone explain it to me? When Vref2 increased by 4%, the output voltage doesn't ...
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### Boost PFC inductor ripple

I am curious about how to calculate the inductor ripple of a boost PFC. Because the input voltage doesn't have a constant value, the ripple is related to Vin, so when the boost PFC works, the inductor ...
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### PFC inductor calculation [closed]

I have a question about PFC inductor calculation. Please see the below figure. This is my answer, but I don't know how to only let Lmin equal to Vrms, P, fs. There is a V (output voltage) in there. I ...
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### GFCI tripping when using hair trimmer, but only when using an extension cord

I have a GFCI socket in a recently-build bathroom. My hair trimmer trips it often when stopping under some conditions and while I have a fix I'd like to better understand what exactly is going on here....
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### Does the PFC stage adjust its output power depending on the load requirements of downstream converters?

I am trying to calculate the overall efficiency of a PFC+flyback converter. The PFC boost converter has an efficiency of 0.9 and the flyback an efficiency of 0.89. Depending on the load which requires ...
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### X2 polypropylene capacitor for DC smoothing after AC rectification

Can a X2 polypropylene film capacitor be used for dc smoothing at the output of a bridge rectifier? I want to use this capacitor at the input of a power factor correction circuit with a switching ...
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