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phase difference to proportional voltage output...

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desertkids

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how can i convert the PWM pulse width to proportional voltage output??the article is write like this,please help see wat should i do...

"If you apply the two square waves to an exclusive OR function, you will get a PWM output where the displacement angle determines the waveform output. For power factor measurement, we are interested in the angles between 0 degrees and 90 degrees. At 0 degrees, the two wave forms are in phase, and so the PWM output is 0% ON. At 90 degrees, there is a 50% overlap, so the PWM output has a 50% output. This waveform can then be filtered to give an output voltage proportional to the displacement angle from 0 degrees to 90 degrees."

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i have find a ic that can do this job,AD8302 RF gain and phase detector..but i cant buy it from malaysia market..any similar ic suggestion or other analog circuit??thanks...
 

the square wave average voltage is its high multiplied by its Duty cycle (i.e. Vdc=DutyCycle*(Vhigh-Vlow) which is proportional to Duty Cycle i.e. proportional to the width of the pulse.
 

safwatonline said:
the square wave average voltage is its high multiplied by its Duty cycle (i.e. Vdc=DutyCycle*(Vhigh-Vlow) which is proportional to Duty Cycle i.e. proportional to the width of the pulse.

but what i need is a ic or circuit that can convert the pulse width to proportional voltage out...thanks
 

i meant u just need to filter the output (using an IC or u make a LPF) to do this.
 

safwatonline said:
i meant u just need to filter the output (using an IC or u make a LPF) to do this.

ok,i have found a lp filter to get this...thank you very muz..anyway do u know how to switching capacitor bank to correct power factor??
 

Apart from simply buying a power factor correction controller, you could build it by yourself, but you should try to consider some specifications of existing equipment to avoid reinventing the square wheel.

As one feature, the controller should have some hysteresis according to the kVAr step size of capacitor banks and also a delay to limit switching frequency in case of rapidly changing loads. An obvious today's solution would be a small uP, e. g. a PIC processor. It could actually perform the phase measurement pure digitally, but that would be another topic.
 

FvM said:
Apart from simply buying a power factor correction controller, you could build it by yourself, but you should try to consider some specifications of existing equipment to avoid reinventing the square wheel.

As one feature, the controller should have some hysteresis according to the kVAr step size of capacitor banks and also a delay to limit switching frequency in case of rapidly changing loads. An obvious today's solution would be a small uP, e. g. a PIC processor. It could actually perform the phase measurement pure digitally, but that would be another topic.

Danke schon..Ich spreche ein bischen Deutsch..but wat i nd do is analog PFC...but i near finish ny this project, now only left some testing only...
 

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