Improving Power Quality Using an Integrated Wind Energy Conversion and Storage System (WECSS)

This paper details the modeling, controller development, simulation and analysis of an integrated 2MW variable-speed Wind Energy Conversion and Storage System (WECSS) in dynamic simulation software PSCAD. The WECSS presented consists of a pitch controlled wind turbine directly driving a 2MW permanent magnet synchronous generator (PMSG). The PMSG is connected to its host power system via a controlled full-scale power converter system (PCS). The electrical energy storage system comprises of a capacitor bank connected at the PCS DC bus via a full-bridge DC-DC converter. The WECSS exhibits the ability to isolate the grid from wind speed disturbances, as well as the ability to actively absorb wind energy during severe and sustained grid-side fault conditions. The integrated storage system resultantly allows wind power fluctuations to be buffered and grid-side fault tolerance to be enhanced. A further means of enhancing fault tolerance by limiting the energy transferred into the PCS DC bus during fault conditions is also presented. This is achieved with an imposed sub-optimal rotor speed reference. The WECSS presented optimizes wind energy capture, whilst improving wind power quality. The key challenge posed by the integrated WECSS is the design of the resulting multiple-input, multiple-output (MIMO) supervisory control system.