If you want to take a lot of the control load off the PIC you could look at ICs like the Mitel (was Plessey?) SA828. This does total 3 phase sinusoidal PWM control with lots of bells and whistles. (There is a single phase version too (SA838)). You can set the amplitude and frequency and leave the device to itself until you need to change them - in your application this would largely be set-and-forget. Its meant for motor control as well (where you often DO need to change the frequency ). Price is good - about $NZ6.50 in 1's (about $US3.50) and they are even in stock in NZ (from GEC). Look at www.mitelsemi.com/products/ for details including data sheets and application notes. -----Original Message----- From: Humberto Pinheiro To: PICLIST@MITVMA.MIT.EDU Date: Monday, 25 May 1998 00:24 Subject: Re: 3fase ac power generator >marcel wrote: > >> I am interested to do an project to generate 3 phase ac mains on a ship >> on board there are >> two dc generators dc 220 volts and battery's >> an old tow boat from russia >> siemens makes power bridge's igbt 10 to 50 amps 600 volts >> i saw a design with 80553 pwm to control this bridge >> did any body do research on this which pic could do the job >> the bridge contains rectifier and 6 igbt transistors so one needs 6 pwm >> out puts >> >> Marcel >> >> marbel@xs4all.nl