Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Use a Low Pass Filter to measure Power

Status
Not open for further replies.

pvol

Newbie level 4
Joined
Jan 13, 2008
Messages
6
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,318
Low Pass Filter ?

Hello to all,

i want to measure real power from AC.

is it possible to estimate real power using this circuit?
 

Re: Low Pass Filter ?

is it possible to estimate real power using this circuit?
After processing a 50/60 Hz AC measurement through a 10 Hz low-pass filter, you get zero signal. For an accurate real power
measurement, you have to acquire at least the voltage and current fundamental frequency by amplitude and phase with sufficient
accuracy (assuming the voltage waveform is almost an undistorted sine). Practically, you would oversample the input signal at least
by a factor of four. State-of-the-art energy metering chips, e.g. from Analog Devices, are providing a sample rate, that gives correct
real power measurement also with distorted voltage waveforms, which requires kHz bandwidth.
 

Low Pass Filter ?

I would think using peak detector could be a better idea.
 

Measuring real power actually doesn't require digital processing of sampled signals (although the method becomes more and more popular).
But it either requires measurement of RMS current and voltage and power factor or alternatively averaging the product of current
and voltage momentary values. A peak detector can't measure real power.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top