Electrically Excited Synchronous Motor Three-Level DTC_SVM Control Based on Novel Flux Observer

The accurate observer and effective control of the stator flux for electrically excited synchronous motor, has a significant sense to the performance improvement of direct torque control system. For this, a novel full-order closed-loop stator flux estimator suitable for full speed range was put forward and analyzed detailed in this paper, it pointed out that the estimator was composed of two estimator models, i.e. current model and voltage model, and they switched smoothly because of their properties of filters. Applying the simplified three-level SVPWM algorithm to direct torque control (DTC), can not only implement the accurate compensation for the torque and flux linkage error but also guarantee for maintaining a constant frequency of power device. Furthermore, a novel method of voltage estimate for the three-level power inverter is advanced based on the simplified SVPWM strategy. Experiment results demonstrated that the proposed electrically excited synchronous motor DTC_SVM system based on full-order closed-loop stator flux estimator has excellent control property.