Multi Channels PWM Controller for Thermoelectric Cooler Using a Programmable Logic Device and Lab-Windows CVI

We present a complete design of a multi channels PID controller for Thermoelectric Cooler (TEC) using a pulse width modulation (PWM) technique implemented by a dedicated programmable logic device (PLD) programmed by VHDL. The PID control loop is implemented by software written by National Instrument Lab-Windows CVI. Due to the fact that the implementation is by a VHDL and PLD the design is modular, as a result, the circuit is very compact in size and very low cost as compared to any commercial product. In addition, since the control loop is implemented by software running on a personal computer (PC) using a C language, it is easy to adjust the controller to various environmental conditions and for a width range of sensors like: a thermo couple (TC), thermistor, resistance temperature detectors (RTD) etc. We demonstrate the performance of this circuit as a controller for a small incubator using thermistor as the temperature sensor. Copyright © 2008 IFSA.