measuring floating inductor current in a truesine inverter application

[Jamie Morken]

Hi,

I am trying to make a true sine inverter outputting 120VAC 60Hz,
and am using 200kHz for the fet switch. Also using software PWM
control with either of one or the other of these two algorithms:

method1: (uses high speed DAC)

if inductor current > voltage error, pulse off

if inductor current > current_limit, pulse off

if time > limit pulse off (limit is our max dutycycle for this PWM period)



method2: (uses high speed ADC)

if inductor current > current_limit, pulse off

Duty cycle = ((desired voltage - current voltage) * gain) - (Inductor
current * gain2)



For the current sensing I was thinking of using a hall effect sensor,
like the "S22P025S05" from Tamura,

http://parts.digikey.com/1/parts/945709-sensor-current-25a-2-5v-pcb-s22p-s22p025s05.htmlwhich
has