Abstract: Due to the recent strong demand for silicon steel market, the continuous annealing lines which have been in operation for 10 years have to increase the speed and improve the quality improvement. Because of the single layer of silicon steel getting thinner and thinner, the yield rate and the concession rate of the whole coiling process were more and more obvious affected by the coiling tension. By studying the principle of tension control and tension optimization schemes, a practical tension model for strip coiling was established, which gradually find out the torque accuracy and linearity of the asynchronous motor of the tension reel in weak magnetic region. The optimizations of the motor drive (inverter) and the PLC program make the torque accuracy (winding tension) meet the requirements of the coiling process.

Key words: continuous decarbonization annealing line, tension control model, asynchronous motor, field-weakening control, inverter