12VDC to 24VAC inverter
Posted: Sat Mar 07, 2009 7:31 am
Hi all,
I have a refrigerator in my old motorhome that uses a 12VDC to 24VAC inverter to run a swing motor compressor in it. The inverter is toast and a new one is no longer available. The old one just used a multi-vibrator circuit driving some switching transistors.
I want to replace the old circuitry with a PIC driving some MOSFETS into the step-up transformer from the old inverter. I'd like to get a 60 hz sine wave (or something close) out of the transformer, not the funky looking square wave (ish), using PWM or something.
I'll use the PIC to monitor the refrigerator temperature and compare it to the set-point, also power-down the fridge if the battery voltage drops too low as well other useful functions.
My experience is nil on PWM. Can anyone give me some guidance on how to generate PWM in the PIC and get something close to a sine wave out of the step-up transformer.
Thanks!
I have a refrigerator in my old motorhome that uses a 12VDC to 24VAC inverter to run a swing motor compressor in it. The inverter is toast and a new one is no longer available. The old one just used a multi-vibrator circuit driving some switching transistors.
I want to replace the old circuitry with a PIC driving some MOSFETS into the step-up transformer from the old inverter. I'd like to get a 60 hz sine wave (or something close) out of the transformer, not the funky looking square wave (ish), using PWM or something.
I'll use the PIC to monitor the refrigerator temperature and compare it to the set-point, also power-down the fridge if the battery voltage drops too low as well other useful functions.
My experience is nil on PWM. Can anyone give me some guidance on how to generate PWM in the PIC and get something close to a sine wave out of the step-up transformer.
Thanks!