My name is edris and I am a student.
I am doing a project about a windmill.
I have to make a controller system for this windmill
The first thing I want to know is what is it generating?

So after the 3 phases there is a rectifier and after this I want to measure.

The windmill can generate at average about 50 Volts DC and 10 Amps of current.
So this will make a power generated of about P = U * I > 50 * 10 = 500 Watts
Right? 


Now the problem is I want to measure voltage and current.
And there are alot of ways like a voltage divider with a voltage follower with a opamp that creates high impedance and will let little current through.
That's for the Voltage.

But then I thought maybey if there is a chip/board that can measure both and calculates this and then sends this data to a i2c line.

Now I found a LTC2946 chip 
http://www.linear.com/product/LTC2946 
I actualy don't understand how to set this up. 
The problem this chip needs a sense resistor. On that page they have chosen a 0.02 Ohm sense resistor.

So let's do a little math.

So I know the value of the resistor right? >> 0.02 Ohm
Say my current is 10 Amps >> 

Ohms law = V = I * R right? 
So my voltage will be 10 * 0.02 = 0.2 Volt or 200 mVolts
So can I say then that I need a > 0.2 * 10 = 2 Watt High Power Resistor
Is this right?

Say my current will be 15 Amps. That make 15*0.02 = 0.3 Volts
This will make > 0.3 * 15 = 4.5 Watss of High Power Resistor right? 
I don't know if I am doing this right !

If so then the next problem will occur.

How can I measure voltages with this chip?
I don't understand.


If you guys know anything, help is appreciated.


Kindly Regards,

Edris