I want 12 isolated pwm outputs to control switching of 12 igbts simultaneously. So how can I get those signals using atmega 2560. Also one more thing that I am using spwm method i.e, sine and triangle wave comparison for pwm generation. If this microcontroller is not suited then please tell me which microcontroller should I use?
Thanks
12 PWM outputs are available, but SPWM IMO has to be emulated in software. More powerful controllers often have less output pins, so that a scalable modular system of multiple (small) controllers may be the way to go.
to control switching of 12 igbts simultaneously
Do you really mean simultaneously? A lot of people think that they need that when they don't.
As the built in PWM uses timers with 2 PWM outputs per timer you can never ensure that they are synchronized and thus switch on simultaneously. For true synchronization you have to use an external chip like the PCA9685 as used here:-
What exact kind of synchronization is required? For 3 phase (motor...) control the signals must maintain their phase angle (120°), not the usual 0° angle.