A Novel Algorithm to Differential Scanning Calorimeter Temperature Control Based on Liquid Nitrogen Feedforward Technique

Abstract

Differential scanning calorimeter (DSC) is an important instrument in the thermal analysis which could be pervasively applied to property analysis of inorganic compounds, organic compounds and drugs. An effective temperature control technique could ensure DSC thermal experimental accuracy. Unlike the traditional temperature control methods which have limited temperature control ranges and change rates, this paper presents a novel algorithm which exploits the liquid nitrogen feedforward technique to control the temperature of DSC. To be specific, the proposed approach fully takes advantage of the characteristic of the liquid nitrogen that has the ability to rapidly decrease the objective temperature. Furthermore, a cold-heat synergistic feedforward-feedback control is utilized. On one hand, the feedforward controller is able to avoid the singularities for the amount of liquid nitrogen. On the other hand, the feedback controller is able to compensate for the temperature errors due to external disturbances. The proposed algorithm has been applied to the DSC. The experimental results and analysis prove that the control method is able to change the temperature accurately within a wider range.