El diodo Schottky como atenuador del efecto Seebeck en una celda Peltier para un control PID de temperatura

Abstract

A temperature and humidity control system using a PIC16F877A microcontroller was developed. The system uses a 25 kHz PWM signal to control a TEC1-12706 Peltier cell. On the other hand, we made an ON/OFF control on the ultrasonic humidifier in order to regulate the relative humidity. To control the temperature, a discrete PID controller by using ident and controller PID tools from Matlab software was designed. Besides, we analyzed the behavior of the Peltier cell when a PWM signal is applied to it; the conclusion was that the TEC1- 12706 Peltier cell has a total thermoelectric performance of 33% and both, Seebeck and Peltier effects are present when PWM is used; it was determined that the Seebeck effect causes a significant degradation on the molecular bonds in the thermoelements of the Peltier cell; this undesirable effect reduces the lifetime of the cell to a few hours. However, we propose the 15SQ045 Schottky diode as an effective solution to mitigate the damages that the Seebeck effect may cause to the Peltier cell.