Research on dynamic calibration and dynamic compensation of K-type thermocouple

A new dynamic calibration system composed of semiconductor laser, infrared detector and calibrated thermocouple is established to conduct dynamic calibration of K-type thermocouple. The advantage of the system is the application of a laser whose rise time is nanosecond-level. With it, the dynamic calibration of thermocouple can achieve millisecond-level time constant. In the dynamic calibration process, wavelet noise reduction and nonlinear fitting using BP neural network improve the deficiency of the least squares fitting and reduce the errors caused by fitting. After the process, the time constant of K-type thermocouple is obtained, which has an important reference value for research on dynamic characteristics K-type thermocouple. Thermocouple compensation is modeled with dynamic compensation filter and cross-validation method is used to verify the correctness of the model. A new dynamic compensation filter based on improved particle swarm optimization algorithm is applied to correct the dynamic errors caused by the system, making it closer to the actual values, and the ordinary K-type armored thermocouple compensation curve is given.