Due to the severe nonlinearity and complex mechanism of the temperature at intermediate point of the supercritical units

its accurate control is difficult to achieve.Thus

the method based on affine nonlinear system and feedback linearization was adopted to control the intermediate point temperature.By analyzing mechanism equations of the steam-separator and evaporation zone

the affine nonlinear system model for the intermediate point temperature was established.Moreover

taking a 600 MW supercritical unit the object

the system stability analysis and simulation test were carried out

to verify the anti-disturbance capability of the system under water disturbance and the control effect of the system with unit load ranging from 40%to 100%.Furthermore

comparison of the control effect between the affine nonlinear system and the conventional PID system was performed.The results show more effective performances.