directly PWM TEC

tetrafluoroethane · 11-June-07, 05:08 PM

Can a TEC be directly PWMed with a MOSFET in series switching power at 20kHz or higher? It's for a small refrigerator so switching transients are not a problem. (I'll just have to use a Schottky rectifier to shunt the slight inductive spikes and put a filter on the line to the controller.)
If I add a second, smaller TEC in series, will it make the refrigerator also usable as a freezer?

THRiLL KiLL · 11-June-07, 05:54 PM

i know what you are talking about... but damn... i feel slow.

Nerdz · 11-June-07, 08:36 PM

Grrr, Yes You can. There was some frequency your supposed to keep it under, or else you'll get strange things (and I swear, its Below 100Khz, not 400Hz)

Actually, most electrical refrig's use DC. Use that if possible, or design your own SMPS.

Quote:


	d) If a temperature controller is used, it should be of the linear type or the pulse-width-modulated (frequency at least 400 Hz) type to minimize any detrimental effects of temperature cycling.

From: Thermoelectric cooling, Peltier coolers, cold plates, and heat sinks Ãƒâ€˜ TE Technology

ADD: you might not need a filter, Just a diode across the pelt (for example, a relay with a protection diode)

11-June-07, 05:08 PM		#1 (permalink)
tetrafluoroethane Apex Techie II	directly PWM TEC Can a TEC be directly PWMed with a MOSFET in series switching power at 20kHz or higher? It's for a small refrigerator so switching transients are not a problem. (I'll just have to use a Schottky rectifier to shunt the slight inductive spikes and put a filter on the line to the controller.) If I add a second, smaller TEC in series, will it make the refrigerator also usable as a freezer?

11-June-07, 05:54 PM		#2 (permalink)
THRiLL KiLL PcApEX's PuNK ROckER	Re: directly PWM TEC i know what you are talking about... but damn... i feel slow.

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