It looks like your current is bidirectional with average value of 50A. Thus, for sine amplitude of up to 100A your circuit should work just fine because the output swing meets the minimum linear voltage of 150mV above negative rail (GND) specified in AOL conditions - see below.
However, for amplitude of 120A your circuit will NOT work because the output would have to swing -50mV below ground - see below. Therefore, to be able to measure current of 170A, you would either have to increase Vref to 1.85V or lower the gain so the output stays at least 150mV above ground.
Few additional comments:
There is no need for R31/R32/C22 front-end filter with fc of 34MHz while you signal frequency is just 0.159Hz. Also, adding R31/R32 resistors cause the signal gain to be lowered by 1% (G = 200k/10.1k = 19.8)
There is no need here for OPA388 chopper amplifier with max Vos of +/-5uV - with the maximum current of 120A across 0.5mohm shunt resistor, the max input differential voltage is 60mV. Thus, it would be sufficient to use a linear op amp like OPA392 with max Vos of +/-25uV (max error = 25uV/60mV * 100%= 0.04%) to eliminate additional voltage noise generated by the chopper input bias current spikes across the input resistors. For more chopper info, please review the technical white papier under following link:
