Thermoelectric module power supply is via two lead wires or module power supply posts. Connectors may be attached to the wires.
The standard Peltier module version has positive and negative cables of red and black colors respectively. Heat transfer is toward the module ceramic plate to which the lead wires are soldered.
Thermoelectric coolers are DC devices. Voltage ripple of less than 1 kHz in thermoelectric modules results in their dramatically impaired performance.
A decrease in the temperature difference value is defined with the following formula:
ΔT / ΔTmax = 1 / (1+k2),
Δ Tmax is module's rated maximum temperature difference
ΔT is module's maximum temperature difference with ripple supply voltage
k - power supply voltage ripple ratio.
Example: If Peltier module with maximum temperature difference ΔTmax=72 °C has a power supply with ripple ratio k = 0.2 (20 %), the module's maximum temperature difference will not exceed:
ΔT = 72 /(1+0.22) = 69оС
Ferrotec NORD's specialists recommend using a module power supply with a ripple ratio of up to 0.1 (10 %).
The power supply ripple ratio is defined with the following formula:
k = (Iimp/Iav - 1) x (timp/T)
Iimp, timp is amplitude and duration of current pulses;
IDC is average current,
T is period of pulses.
Pulse current duration of less than 10-3 sec, even in case of high amplitudes (up to ten Imax), has no adverse effect on the thermoelectric modules. Pulse current duration exceeding 10-2 sec result in a considerably reduced Peltier module life.
If variable amplitude current, current reverse or frequent switch on/off mode are used for power supply of modules in the customer's equipment, TMC series of thermoelectric modules are recommended.
If PDM power supplies are applied, supply pulse frequency must exceed 1 kHz.