High voltage, amperage, power factor and frequency sensing, etc

I'm looking to make a generator control, it's a 7.5 kw diesel, can do 120-480V in single phase or 3 phase.. I'd like to be able to monitor amperage/wattage/voltage/power factor and frequency.

What are some ideas for this.. Some chip types designed for this? I've only ever done low voltage stuff though I have a good understanding of isolating HV/LV, etc.

I could use a MAX9924 VR sensor interface chip that would give me zero-crossings and give me frequency from there.. a second one with an inductive pickup could give me the zero crossing for the amperage and I'd probably be able to do some math for the power factor, but they wouldn't give me any analog data.

I'd like to keep the HV and LV sides isolated, so if I can stay away from voltage divider circuits I'd be much happier.


While it's easy to isolate HV current sensors, I don't know of any for voltage measurement. Then HV/NV isolation has to be applied to the digital sensor-controller communication, and the sensor needs a separate power supply.

I suppose a 20:1 isolation transformer would work as a primary isolator, add a resistive voltage divider if necessary, could bias it to 2.5 volt and read it that way.. I feel as if doing it that way you'd be better off having a dedicated processor just for that purpose

Could also rectify and smooth it, compensate for diode voltage drop and then multiply by Sqrt(2) to get the approximation of RMS volts rather than peak.. but you wouldn't be able to figure out power factors that way