Research on an Improved Stator Flux Linkage Observation Method in Direct Torque Control System

Direct Torque Control (DTC), which is widely used as a high-performance alternating current machine motor speed-controlled strategy, has the advantages of simple controlling structure, fast torque response and little influence affected by motor parameters. However , traditional DTC based on the stator flux linkage observer of the u-I model would produce the error of the stator flux linkage, due to the existence of the pure integral element which inevitable brings the accumulation of direct current. Aiming at this issue, a kind of an improved stator flux linkage observation method based on a low-pass fliter was presented. Simulation results show this method is correct and effective.