Solar Mike Guru Joined: 08/02/2015 Location: New ZealandPosts: 1144
Posted: 04:56am 28 Dec 2023
I have been playing with a new controller design, it won't have an inverter fitted to the battery, but I connected a HF 3.5KW 24dc-230vac inverter and checked out the output of the charge current sensor. With a load of 500 watts or so there is a 100hz ripple on the dc current sensor output, approx 100mV; just over an amp charge.
At low charge currents this 100mV ripple causes in my case abnormal MPPT current tracking data, with higher charge currents 10's of amps, has little affect. I got around this issue by over sampling the charge current by 512 times and dividing the result by 512, rejecting any decimals, this averaged out the 100 HZ DC ripple and now works ok.
On other controllers I usually have a 10Hz 18db active filter after the sensor, so the problem hasn't been evident, this particular design doesn't have it.