Lets see if I understand correct.
Say that the TEC I am going to use draws 20A at 12V.
If I run a 50% duty cycle on the PWM then the the TEC will be as if it is working at 6V 10A.
But in fact it is running at 0A 0V for 50% of the time and 20A 12V the other 50%, because of this the PSU needs to be able to withstand the 20A that is being drawn by the TEC 50% of the time even though that switching frequency in the TEC is over 2000 times a second?
Please correct me if I'm misunderstanding what you are trying to say.
Just a quick question, will this method require cooling of the FET I might use?
I have found this topic on another forum a while back, it applies the same idea I have only with a ready to go fancontroller as PWM means.Topic
search for "N-channel MOSFET 96A 100V TO220 IRFB4410" to find the part about the MOSFET he is using
search for "20/12/08" to find a picture of how he build his transistors. Those black boxes are heatsinks? are these always needed when working with high amp MOSFETs?