ADE7880 support 0.001kwh measurement resolution

Hello

         Have any comments for above? 

        if customer would like to use ADE7880 for EVSE charging station. Is it a suitable solution to meet 0.001kwh measurement resolution (3 digit below decimal point on display ) ?   Thank you. 

BR

Patrick

HI Patrick 

what is the voltage, max current , nominal current , do they require a specific imp/Kwh, sensor if ct what is the burden value? 

Dave

Hello Dave

            Please refer to below specification. Thank you. 

Voltage:  220V/380V AC
MAX Current:  40A
nominal current:  32A
specific imp/Kwh:  For ADI default, not spcific
CT burden value:  2.2ohm

BR

Patrick

Hello Dave

     Per my understanding, ADE7880 could support 0.001kwh measurement resolution on display, right? Thank you.

BR

Patrick

Using 220 and 40amps Max and 35amps nom with a 2 ohm burden and 1000:1 = .08mvrms to the current channel adc

using a WTHR of 3  I get these conversions constants

220 * 35 = 7,700watt 

over 1 hr   you will get  7700 / 0.000252458 =30,500,122 LSB at Inom

over 1 sec you will get 30,500,122/3600 = 8,472 codes 

watthr register over 1 sec = 8,472  * 0.000252458 =  2.138824176 watt/hr accumulation over 1 sec

This is at I nom(35amps) as you go down in dynamic range the number of lsbs goes down. 

at 1000:1 the lsb in 1 sec will be 8472/1000 or 8.472lsbs 

So the question is over time yes you can display .001WHRs but at first you may not have enough bits but as you accumulate energy you will get the resolution you require. 

I hope I didn't drag this out maybe just the 0.000252458 WHR/LSB was enough

Dave

Thanks. Dave.