Inverter Shunt Resistor - DSP

[unavezmasysale]

Hi,
I need to sense the output current of an inverter and I will use a shunt resistor to ground at the end of this. The input of the inverter is 400Vdc and the max current is 1A with a frequency of 30Hz and a duty cycle of 50%.
The signal waveform will be like this:



over the shunt resistor. The peak voltage is 400V and Vrms is 200V.

I need to sense it with the ADC of a DSP of 3.3Vcc.

Can you help me to design a good circuit to the ADC considering that the tension should be focused on 3.3V/2 = 1.65V (Differential amplifier?) and the dissipated power over the shunt resistor must be low?

In my country I can buy resistor of metal film (1% from 10ohm or 2% from 0.22ohm)

Thanks you very much.

 

[crutschow]

You want to use a small shunt resistor and amplify its value with an op amp to minimize dissipation in the sense resistor. But too small a sense resistor can allow noise pickup to be a problem so it's a tradeoff between noise pickup and power dissipation. Typically you probably want about 50-100mV minimum across the sense resistor at 1A.

 

[unavezmasysale]

Thanks Crutschow, do you have any circuit or idea to design it ?