Power control circuit for improved power application and temperature control of thermoelectric coolers and method for controlling thereof

A method of controlling the application of power to a thermoelectric device to maintain the temperature of the thermoelectric device at a set point, said method comprising the steps of;

• providing an electrical power source for supplying alternating current;
• acting on said alternating current to produce rectified alternating current;
• providing comparator means having an inverting input, a non-inverting input and an output;
• providing a predetermined value of voltage derived from said rectified alternating current to the inverting input of said comparator means;
• determining the operating temperature of said thermoelectric device;
• providing a voltage to the non-inverting input of said comparator, the value of said voltage being determined by the difference between the determined operating temperature of said thermoelectric device and the set point temperature;
• providing switching means operatively connected between said thermoelectric cooling device and a power source;
• and
• providing control means which is operatively coupled between said switching means and the output of said comparator means, said control means activating said switching means for a predetermined time, determined by the output from said comparator, to allow the rectified alternating current to reach a desired voltage across said thermoelectric device at which time said control means deactivates said switch means, wherein the value of the desired voltage is determined by the set point temperature.

A method of controlling an operating temperature of a thermoelectric device to maintain the operating temperature of the thermoelectric device at a set point, said method comprising the steps of:

• initiating operation of the thermoelectric device;
• determining the set point which is desired for the thermoelectric device;
• determining a low target value of temperature which is below the set point;
• determining a high target value of temperature which is above the set point with the difference between the low target value and the high target value fixed at about 0.5% to 1.0% of a desired control range of the operating temperature;
• modifying the low target value downward if the operating temperature i s above the set point while maintaining the fixed difference between the low target value and the high target value;
• modifying the high target value upward if the operating temperature is below the set point while maintaining the fixed difference between the low target value and the high target value;
• ceasing to modify the low target value and the high target value when there is convergence of the set point and the operating temperature of the thermoelectric device;
• and
• applying a value of power less than 100% power to the thermoelectric device to maintain the operating temperature of the thermoelectric device between the high target value and the low target value.