phase and power calculations | Cypress Semiconductor
phase and power calculations
Hi, as an intern student I am new at Psoc 4 and I am stuck with a problem. I have been given a project on home energy monitoring, therefore I have to make some calculations like phase difference, active and reactive power. I want use a shunt resistor with small value to measure the current passing through the system. However, because the harmonics are crucial for power calculations and we want to observe detailed features like "harmonic signatures" of the devices, we want to make like 1000 measurements per second. And the magnitude of the current is expected to be in the range of 10mA-10A. According to my employer, although the bandwidth of the current is broad, the shunt resistor approach is fine. Until here, everything is okay, but the problem is I am having trouble on these calculations. I know, I should use a SAR ADC to pass the measurements into the digital and maybe a PGA if the current is too low for ADC, but after passing to the digital I do not know how to calculate phase and power. For example, does the fact that I have to measure the current and voltage 1000 times in a minute mean that I should calculate phase and power(both active and reactive) in each time? Or is the phase difference constant as in simple circuits? As an approach, could I find the phase difference by finding when the current and voltage achieve their peak values in a period then by subtracting these values and dividing the result by the line voltage period( 1/50Hz )?
I know, I asked lots of questions and my writing is a little bit messy. I will be grateful for any help&idea,