Unit Commitment Based Controller for Grid-Connected PMG-Based WECSs with Battery Storage Units

This paper presents a controller for operating the generator-side ac-dc power electronic converter (PEC) of a grid-connected permanent magnet generator (PMG)-based wind energy conversion system (WECS) that has battery storage units (BSUs). The proposed controller is developed based on the Lagrangian Relaxation unit commitment (LRUC) method to determine the command electromagnetic torque, T_e* to be developed by the PMG at each wind speed. The value of T_e* is set to adjust the power produced by the PMG in order to meet the power demands of the generator-side PEC and BSUs. The LRUC-based controller is implemented for performance testing on a grid-connected 7.5 kW PMG-based WECSs with 4.44 kW BSUs. Performance tests are conducted for changes in the wind speed, active and reactive power delivered to the host grid, and system parameters. Test results show that the LRUC-based controller is capable of adjusting the power produced by the PMG to meet the power demands of the generator-side PEC and BSUs. This capability is found to have minor sensitivity to the changes in wind speeds, levels of the power delivery to the host grid, and state-of-charge of BSUs.