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# 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.

29 questions with no upvoted or accepted answers
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1answer
215 views

### Control of interleaved boost converter

In a school project we will try to implement a control system for a boost power factor correction (PFC) converter. The converter circuit can be seen below (http://www.ti.com/lit/an/slyt517/slyt517.pdf)...
0answers
226 views

### Large negative current spike in N-Channel MOSFET source when turn-off

I am working on repairing a power supply board of a LCD TV (200W power), more specifically, the PFC section (active power factor correction). See schematic (adapted from here): I've replaced some ...
1answer
2k views

### Power factor improvment c/k ratio

All power factor improvment controller has a setting c/k ratio. Their manual says it is the lowest step of capacitor bank. It controls switching threshold. But how what is its significance?
0answers
28 views

### How does at low power factor impedance (p.f=R/Z) (if R is constant ) increases while current also increases?

Impedance is equivalent resistance of circuit having resistive and reactive components so if we keep R constant and increase inductance than Z will increase and power factor will going to decrease as ...
0answers
36 views

### How can we make a load that has configurable power factor for 230V AC?

We are hoping to create a lab for students at our university that requires them to measure the power factor and correct for it. We are working with 230V AC and have a maximum power of 300W. We were ...
1answer
54 views

### Is Power Factor only relevant at rated load in Light Equipment?

As you might know, LED lamps over 25W require a minimum 0.9 power factor in Europe. I have designed a PSU for a specific LED lamp which is rated about 50W. There is a PFC-stage (crm) in order to ...
1answer
74 views

### Does using electronics with poor power factor affect the pulse power capability of a generator rated for a certain KVA?

The situation is such: There is a multi-pole, three-phase, permanent magnet generator (rated for 100 KVA, let's say) that feeds into a simple diode rectifier with a capacitive/DC Voltage load (...
0answers
251 views

### Which power factor is better in an industry -0.21 or -0.94 and why?

In the electrical panels , when i switched on-off the capacitor bank then power factor gets shifted from 0.89(lagging/during OFF condition) to -0.87(leading/during ON condition) , similarly on ...
1answer
66 views

### Complex Power and pF correction

I was responsible for making up my own question and providing the answer to the problem. I was just wondering if someone could check my work, I would go to my schools tutoring thing but they are ...
1answer
140 views

### Grid tie inverter power factor

After installing a grid tie inverter (GTI,) the power factor dropped from 1 to .85 over the last week. My loads are a combination of inductive and resistive. I have an option of setting my GTI to ...
3answers
1k views

### Power factor relation with load

I was reading about power factor in electronic devices and I found charts showing that usually the power factor varies (usually decreases) with the load. So if you have a device that either works with ...
0answers
124 views

### Open Delta's “virtual” power factor

Open Delta yields 57% of power instead of the 86% it would yield if no 30-degree angle gets in the way. Can that 30-degree angle be corrected with a capacitor and an inductor (it requires a cap in one ...
0answers
62 views

### PFC Application Report equation terms

I am working on a PFC for a final project. The PFC is based on several sources and runs in CCM, currently have it working with a very noisy current waveform. My original design was to use a 60kHz ...
0answers
24 views

### Power in balanced three phase systems

I was solving the following exercise And got the a) and the c) correct: $\ Iline = 14.6 - 5.95j (A)$ $\ power factor = 0.926$ I turned the delta connection into a wye connection and got: \\$...
0answers
21 views

### Conduction Mode in PFC

At a Power-Factor-Correction (PFC) circuit, Why mostly using Continues Conduction Mode (CCM) for high power applications, ex. above 300 kW, and using Boundary Conduction Mode (BCM) or Discontinuous ...
0answers
62 views

### Why does rectifier output is showing DC instead of pulsating DC

I am using below circuit for PFC. Before connecting coupled inductor's auxiliary output to the IC's Vcc, I wanted to make sure that it is coming properly or not. So when I probed the red dot in the ...
0answers
17 views

### L6561 PFC based SMPS - will it operate properly when running the whole unit off HV DC supply?

In a near-aircraft fixed ground application I have to run a special, multi output SMPS which has a L6561 based PFC front end. So far this SMPS was run off regular 230 V 50 Hz mains, but ...
0answers
60 views

### PFC boost converter is not stepping up the voltage

I am making a PFC circuit for AC-DC converter. I am facing a weird issue. As per my design the output of the circuit should be 390VDC, but I am getting 311VDCrms with ringing (overshoot 360V, ...
0answers
36 views

### How to estimate the power consumption of a motor when running at low load

I am trying to calculate the electrical power cost-saving of reducing the amount of time a machine runs idle (when the motor is running unloaded). From the meter data, the amps when idling is about ...
0answers
44 views

### Readings for a current transformer reversed

What would happen to the measured values of a circuit (real power, apparent power, power factor, current) if I install a current transformer "backwards"? Usually a current transformer has some ...
1answer
50 views

### Experiment with transformer: meaning of some physical quantities

I'm doing some experiments with a transformer, measuring some physical quantities. First I did an experiment with the transformer in open-circuit. I determined the voltages and currents on both ...
2answers
43 views

### on a network analyzer's measurement what's the meaning of a negative PF?

on a 1 MVA transfomer, process in the place is plastics injection machinery. On the plotted data from an analyzer results in PF jumping from 0.998 to -0.997 (roughly) for all the measurement period ...
1answer
400 views

### Generator shutdown on leading power factor

I am having some issues in one of my projects. We have installed a generator in a building, where power factor is leading and -kvrs are shown on controller display. We know that this building is ...
0answers
922 views

### Power factor and Harmonics associated with Electric Vehicle charging

What is the power factor associated with (typical) DC fast chargers and onboard chargers in electrical vehicles? Also, how much is the harmonic content (especially triple-N harmonics) associated with ...
1answer
482 views

### Power Factor Correction Circuit (LED lighting)

I've been researching how to design power factor correction into an agricultural LED lighting system. My client requires at least a 0.95 power factor. I'm planning to use PWM controlled buck ...
0answers
471 views

### Inrush current limiting circuit

For my boost PFC design that I am currentely working on, I need a current limiting circuit for the capacitor inrush current in start up, the widely used circuit in this type of applications cases is ...
0answers
107 views

### Sensing AC voltage

In a project I'm working on (Totem pole PFC) I need to sense the input AC voltage, scale it down, rectifing it/adding an offset and then send to the ADC of the digital controller to use in the control ...
0answers
54 views

### Transformer Leakage Inductance and power factor

How does transformer leakage impedance affect power factor? Or how does the X/R ratio of the transformer change the power factor ?
0answers
380 views

### MC34262 PFC not reaching desired output voltage

I'm building a 450W PFC with a MC34262. It's the first time I build a PFC. I based my circuit on the reference design of page 12 of the datasheet. I'm testing with two 100W incandescent lamps in ...