Voltage,current and phase detector.

[leoren_tm]

phase detector

Using an op-amp.is it possible to design a circuit that would be able to detect Voltage, current and phase angle? considering the output of the system could be read by ADC on a microcontroller. and also, what is the basic priciple on measuring power factor of the system?

 

[michael58]

phase detector phase to voltage conversion

I guess the microcontroller You are using must measure delay between two signals: Voltage and Current, see the attasched sch, and so calculate the phase angle.

 

[FvM]

phase angle between voltage and current

Generally, power factor is the quotient of real and apparent power (P/S). On ly in case of linear loads (sinusoidal current), the measurement can be reduced to the determination of phase angle between current and voltage. Then the current and voltage sign signals contain sufficient information.

 

[leoren_tm]

phase angle detector

I guess the microcontroller You are using must measure delay between two signals: Voltage and Current, see the attasched sch, and so calculate the phase angle.

oh thanks for the reply...op-amp act a votage-to-current converter..thank for the schematic, ill start at the logic

Added after 2 minutes:

Generally, power factor is the quotient of real and apparent power (P/S). On ly in case of linear loads (sinusoidal current), the measurement can be reduced to the determination of phase angle between current and voltage. Then the current and voltage sign signals contain sufficient information.

can i learn tru some sample circuit?
and on a ADC, voltages are being measure right?

 

[FvM]

current voltage phase factor

A general hardware, that is suitable for a phase angle and a true P/S measurement as well, is formed by an uP measuring voltage and current. An Microchip AN suggested in another recent thread gives an example.
https://ww1.microchip.com/downloads/en/AppNotes/00939a.pdf

A simple setup for a phase angle measurement: Have comparators for voltage and current signals and an XOR gate combining both signals. The duty cycle of it's output (a 100 or 120 Hz square wave) represents the phase angle respectively the power factor. You get 0% d.c. (voltage and current in-phase) for real load and 50% d.c for reactive load. A simple low pass converts the duty cycle to an analog voltage. An additional FF gives the power factor sign (capacitive/inductive).

 

[leoren_tm]

phase detector power factor

oh great thank you soo much....ill read the app notes....maybe ill need some to time to read it, and have more question.