I am building a solar charge controller. I have based the design on pwm5 by Julian illet (circuit diagram attached). I am trying to convert this PWM charge controller in to a mppt one.
The buck converter I am using is shown on the second picture. Switching frequency is 31.5 kHz. I have no idea of the inductor I'm using (see the third picture).
My problem was that both IRF3205 are getting very hot. But the IRF3205 I'm using as a diode in the buck converter stopped heating up when I changed the switching frequency to 31.5kHz.
Switching MOSFET is not heating up when it is operating in PWM mode, but the addition of the buck converter circuit makes it toasty. There are no heat sinks on any of the MOSFETs.