Voltage Control of a Stand-Alone Multiphase Doubly Fed Induction Generator

This article presents a multiphase doubly fed induction generator (MDFIG) with a dedicated and unique control algorithm in a stand-alone wind energy conversion system. The algorithm has been developed and elaborated in the case of different emergency modes. Compared with the traditional double-fed induction generator, the MDFIG has increased reliability, reduced current level per phase, and low rotor harmonic currents. The control system is based on a classical mathematical model and the stator field-oriented control method. However, especially for the wind turbine system, the control system has been extended for dedicated five-phase operation and additional scenarios have been added. First, the dynamic states of the generator operation under normal operating conditions with voltage variation and load were simulated and compared with laboratory tests. Second, the fault-tolerance results of rotor phase failures with different states and loads were presented. This performance is validated in the laboratory with a 4 kW prototype MDFIG. The method presented in this article is simple, robust, and cost effective with MDFIG and has significantly improved the reliability of the power generation system.