there is an inverter specification of 48V dc battery input and 3 phase ac output is given as 3*(0......32V), Does this mean that 32V is a line voltage output and my power output is corresponding to sqr(3)*32 *I*Cos(phi) or 3*32*I*cos(phi)?

 

I interpret it as you have three phases of output spaced 120° apart, variable from 0VAC to 32VAC RMS, the peak-peak values being ~45.255v

 

what does the name plate power rating indicate?