Peltier element controller method, 20Amps bidirectional current

[KlausST]

Hi,

I cannot see why you need some PWM system running at Mhz frequencies to generate dc. Just switching max dc current on and off at 10 Hz at the correct duty cycle would work fine. Think how well mains phase control works for heaters and incandescent lamps. Anything faster just generates EMI and switching losses.

With peltiers you should not use pulsedmode because of efficiency.

The thermal transport is about constant to average current.
But there are resistive loss (just generating heat without cooling effect) ...they depend on RMS current.

With DC current (not pulsed) average current is the same as RMS current.
But with pulsed mode the RMS current is higher than the average current.

This means with pulsed current you have decreased efficiency because of higher loss compared to thermal transport.

Connecting an inductance in series with a peltier, using higher (no need for Megahertz), and driving the full bridge in slow decay mode should be sufficient.

Klaus