DFIG-based WECS Fault Ride through Complying with Australian Grid Codes

Doubly Fed Induction Generators (DFIGs) are widely used in variable speed wind turbine owing to its superior advantages that include ability to extract more energy from turbine, capability to control active and reactive power independently and the use of reduced converter rating that reduces its overall cost. On the other side fluctuating output power, weak fault ride through capability and high sensitivity to grid disturbances are the main issues that affect DFIG performance. In this paper, superconducting magnetic energy storage (SMES) unit is proposed to improve the fault ride through (FRT) capability of DFIG-based wind energy conversion system (WECS) during voltage sag and voltage swell events in the grid side. A new control approach for SMES unit using hysteresis current controller (HCC) along with proportional integral (PI) controller is introduced. Australian grid codes are used to examine the capability of the proposed controller to improve the FRT of the DFIG and hence maintaining the wind turbine connection to the grid during studied faults. Simulations results show the effectiveness of the SMES controller in maintaining system parameters within safety margins that comply with the Australian grid codes.