LC Filter for 2.69V 250Hz AC to Pure DC: Capacitor and Inductor Value Selection

294 9

Best answers

How do I design an LC or pi filter to smooth a rectified 2.69 V, 250 Hz AC signal into pure DC when the output is still highly pulsating?

To get smoother DC, place a capacitor immediately after the rectifier/diode and then add the LC or pi filter after it, because the rectifier plus smoothing capacitor does the first stage of DC smoothing [#21684447][#21684449] If the ripple is still high, the issue may be the smoothing capacitor itself, so try a tantalum capacitor or parallel different capacitor types before the filter [#21684452]

AI summary based on the discussion. May contain errors.

Report a violation of the law

Reply | New topic

#1 21684446 18 May 2020 22:18

Elliot Omoru Elliot Omoru

Anonymous

Post #1
21684446 18 May 2020 22:18

Good day all, i am am designer a LC filter for a 2.69v ac source at 250HZ, and i have succeeded in rectifying the ac input to pulsating dc. i want to get a pure dc voltage and current . i have done series of calculations on the capacitor and inductor value for the LC filter design but my output still remains pulsating. can anybody give me idea on how to go about the filter design. Thank you
ADVERTISEMENT
#2 21684447 18 May 2020 23:19

Elizabeth Simon Elizabeth Simon

Anonymous

Post #2
21684447 18 May 2020 23:19

To convert AC to DC you need some sort of rectifier and not just a filter. So just use a diode and capacitor and you should have pretty good DC. Then maybe put your filter after that if it's not good enough.
#3 21684448 18 May 2020 23:24

Elliot Omoru Elliot Omoru

Anonymous

Post #3
21684448 18 May 2020 23:24

yes i have already done the retification but i cant design the filter for the rectified output
ADVERTISEMENT
#4 21684449 19 May 2020 01:59

Elizabeth Simon Elizabeth Simon

Anonymous

Post #4
21684449 19 May 2020 01:59

Are you using a pi filter? How much pulsing are you seeing?You need to put a capacitor right after the diode then add the LC filter if needed
ADVERTISEMENT
#5 21684450 19 May 2020 13:17

Elliot Omoru Elliot Omoru

Anonymous

Post #5
21684450 19 May 2020 13:17

yes ma i am using a pi filter and the pulsation is high , let me try what you have suggested, Thank you very much ma.
#6 21684451 20 May 2020 06:47

Andrs FEHR Andrs FEHR

Anonymous

Post #6
21684451 20 May 2020 06:47

What is the requirement of the ripple?
ADVERTISEMENT
#7 21684452 20 May 2020 07:20

Andrs FEHR Andrs FEHR

Anonymous

Post #7
21684452 20 May 2020 07:20

The problem can be the High frequency quality of the smoothing capacitor after the rectifier, try Tantal capacitor, or parallel different types (before the filter).
#8 21684453 20 May 2020 17:53

Elliot Omoru Elliot Omoru

Anonymous

Post #8
21684453 20 May 2020 17:53

Thank you very very much , it worked
Turn-on surge limits rectifier and capacitor sizing
#9 21684454 23 May 2020 02:54

PeterTraneus Anderson PeterTraneus Anderson

Anonymous

Turn-on surge limits rectifier and capacitor sizing
Post #9 21684454 23 May 2020 02:54

For higher-voltage off-line rectifiers we need to consider the initial turn-on surge. Have you ever plugged-in a wall-wart power supply, and seen a spark as the prongs make contact? This is power -on surge. What happens, is that the discharged capacitor across the rectifier output forms a temporary short circuit for the first half-cycle of the input AC. Rectifiers have a "Non-Repetitive Peak Forward Surge Current" rating. There must be enough resistance or inductance in series with the rectifier to prevent this rating being exceeded at turn-on. Capacitors have AC current ratings also, though I don't know how to convert this to non-repetitive peak current rating.
#10 21684455 31 Jul 2020 23:07

Grace GraceJordan Grace GraceJordan

Anonymous

Post #10
21684455 31 Jul 2020 23:07

Everyone can use https://qweetly.com to find some inspiration to write academic papers. They have a rich database of assignments on different topics.
Create an account, log in here. You will receive points by participating in discussions.
Join this discussion.

Install Elektroda application

Didn't find an answer? Ask Artificial Intelligence (AI)

*I agree to send the question to OpenAI, Google LLC - owners of language models in order to prepare the best response. The companies may monitor and log information entered into the form.

*I agree to publicly display my question and answer. The question and answer will be publicly available to everyone. The process may take a few minutes. Upon completion, you will be redirected to the page with the answer.

Wait...(2min)

Reply | New topic

Report a violation of the law

Topic summary

A designer working with a 2.69 V, 250 Hz AC source has successfully rectified the AC input to pulsating DC but struggles to achieve a pure DC output using an LC filter. The discussion clarifies that rectification requires a diode and capacitor stage before filtering. It is recommended to place a smoothing capacitor immediately after the diode rectifier to reduce ripple significantly, followed by an LC or pi filter if further smoothing is needed. High ripple levels suggest the need for improved capacitor quality; using tantalum capacitors or paralleling different capacitor types can enhance high-frequency smoothing performance. Additionally, considerations for inrush current and surge protection at turn-on are important for capacitor and rectifier longevity. Implementing these suggestions resulted in successful ripple reduction and a more stable DC output.
AI summary based on the discussion. May contain errors.

LC Filter for 2.69V 250Hz AC to Pure DC: Capacitor and Inductor Value Selection

How do I design an LC or pi filter to smooth a rectified 2.69 V, 250 Hz AC signal into pure DC when the output is still highly pulsating?

Didn't find an answer? Ask Artificial Intelligence (AI)

Topic summary