3 phase 3 wire measurement

[ajitnayak87]

Dear all,

I am trying to build 3 phase voltmeter that could measure L-L and L-N voltage during 3 phase 3 wire and 3 phase 4 wire connection. 3 phase 3 wire and 3 phase 4 wire connection are external connection.

as we know in 3 phase 4 wire we will get neutral reference so we can get accurate reading for L-L and L-N.
but in case of 3 phase 3 wire we dont have neutral reference .In this case it will be difficult to get gnd reference. I would like use both connection type in common circuit,

I have seen one of the product where they using V-X-M-H IC , can some one suggest me functionality of this iC. i have attached schematic for reference.

If any other suggestion with schematic will be appreciated. to differentiate 3 phase 3 wire and 3 phase 4 wire

 

[Pommie]

Can you just use some suitable resistors in a star formation to make a virtual neutral?

Mike.

 

[ajitnayak87]

Dear sir,

I have attached some of circuit used and tested . I need help in to complete isolation and grounding part to MCU,
How can do this using differential amplifier circuit.
Circuit 1: purely based on voltage divider network and for delta connection. I wanted to use common circuit for both star and delta. how can i isolated the ground here.

Circuit 2: Using V-X_m_H ic OR TA1G label printed on it. i am curious to know what this ic will do??

 

[ajitnayak87]

is any one used
You might want to look at the following products:

https://datasheets.maximintegrated.com/en/ds/78M6631.pdf

**broken link removed**

https://www.digikey.com/reference-designs/en/power-management/energy-metering-for-ac/833

https://www.analog.com/en/products/ade7880.html#product-evaluationkit

https://www.analog.com/media/en/technical-documentation/data-sheets/ADE7880.pdf


I have tested with 3 phase 4 wire its working well, But how can i do calculation part in 3 phase 3 wire system in software