LD temperature control system based on self-tuning fuzzy PID algorithm

In order to make a laser diode(LD) work stably, a highly efficient temperature control system was designed and implemented. The system was made up of the MSP430 microcontroller, negative temperature coefficient thermistor(NTC) and thermoelectric cooler(TEC), respectively, as control unit, temperature sensor and actuation element. Based on the self-tuning fuzzy PID algorithm, the negative feedback loop was adopted for controlling the temperature of a laser diode and enabling it to work stably. Experimental results show that the system stabilized the temperature within 250.05 ℃ in 68 seconds when it rose from 21.9 ℃ to 25 ℃. After 94 seconds, the temperature can stay within 250.008 ℃. Compared with a conventional PID control system, the temperature control system based on self-tuning fuzzy PID algorithm can adaptively adjust PID parameters in the system without manual operation. Therefore, the system has a better dynamic performance.