Research On Temperature Control System Identification And Control Method For Laser Diode

In order to achieve the high precision temperature control of semiconductor laser, designed a temperature control experiment system which use thermoelectric cooler, temperature sensor, radiator of semiconductor laser and Field﹣Programmable Gate Array embedded system developing platform. The specific research content is as follow:First, proposed the temperature measurement method which depends on the principle of the time constant measure the value of the thermal resistance.Effective use the Hardware logic functions of Field﹣Programmable Gate Array realize the wide range and high precision temperature measurement the range of temperature measurement is 10°C~50°C. Resolution of temperature reaches 0.0031°C.Secondly, established the mathematical model and the corresponding transfer function of the temperature control experiment system which utilized thermodynamic analysis method depending on theoretical analysis of experiment system. According to the character of model parameters, presented an identification method of model parameter which combine the empirical curve of step response and nonlinear least square curve fitting on the condition of obtaining temperature data of semiconductor laser. The model parameters are used to the system simulation and experimental verification. The results show that fitting curve and emulation curve is consistent with experimental curve, which confirmed that fitting model parameter have better prediction accuracy. The result is instrumental in optimizing temperature control algorithm.Finally, proposed a method of heat balance with switch-mode heating and cooling base on the traditional temperature control. According to this method improved the thermoelectric cooler driving mode, and set up two types of work patterns with the ambient temperature. Proposed the solution of temperature control combined Bang-Bang control and PID control, which is applied in two types of work patterns. Bang-Bang control is used to the fast response of temperature control; digital PID algorithm is used to a fine adjustment of temperature base on the parameter identification of control system. Theoretical and experimental results show that the solution of temperature control combined Bang-Bang control and PID control was practicable. The control precision is better than±0.025°C.