Design and Analysis of Wind Turbine Systems with Open-Circuit Fault-Tolerant Control for Outer Switches of Five-Level Rectifiers

Abstract

This paper proposes a tolerant control for the open-circuit fault of the outer switches in three-level rectifiers (both 5L-NPC and T-type topologies) used in wind turbine systems.  In this paper we increase the levels of NPC inverter if we increase the levels of inverter voltage level will be increased and thd will be reduced. A five-level converter is used as the power converters of wind turbine systems because of their advantages such as low-current total harmonic distortion, high efficiency, and low collector–emitter voltage. Interior permanent magnet synchronous generators (IPMSGs) have been chosen as the generator in wind turbine systems owing to their advantages of size and efficiency. In wind turbine systems consisting of the three-level converter and the IPMSG, fault-tolerant controls for an open-circuit fault of switches should be implemented to improve reliability. This paper focuses on the open-circuit fault of outer switches (Sx1andSx4) in three level rectifiers (both neutral-point clamped and T-type) that are connected to the IPMSG. In addition, the effects ofSx1 andSx4 open-circuit faults are analyzed, and based on this analysis, a tolerant control is proposed. The proposed tolerant control maintains normal operation with sinusoidal currents under the open-circuit fault of outer switches by adding a compensation value to the reference voltages. By using the simulation results we can analyze the effectiveness and performance of the proposed tolerant control method.