Research on SVM-DTC of speed sensorless PMSG for the direct-drive wind generation system with CSC

For the speed sensorless permanent magnet synchronous generator (PMSG) for the direct-drive wind generation system (DDWGS) with current source converters (CSCs), this paper presents a stator flux-oriented direct torque control method based on space vector modulation (SFO-SVM-DTC). By the method, the most appropriate current space vector will be generated dynamically to fully compensate for the actual output torque and flux errors referred to the reference commands and to achieve a high performance DTC system with constant switching frequency. In addition, for the stator flux observation, a modified integrator with an adaptive compensation is adopted to solve DC drift in a pure integrator. Simulation and experiment results show that the proposed SFO-SVM-DTC method can effectively not only improve the system steady-state performances but also benefits to achieve the unit power factor control of the PMSG.