Testing a Unit Commitment Based Controller for Grid-Connected PMG-Based WECSs With Generator-Charged Battery Units

This paper presents the performance of a controller for adjusting the power generated by the permanent magnet generator (PMG) in a wind energy conversion system (WECS), which has generated-charged battery units (BUs). The proposed controller is based on the Lagrangian relaxation unit commitment (LRUC) method to determine a command value for the PMG electromagnetic torque (T
_e
*) at each wind speed. The determined value of T
_e
* is set to calculate command values for q-axis currents that are required by the controllers operating the generator-side and charging power electronic converters (PECs). The performance of the LRUC-based controller is experimentally evaluated for a grid connected 7.5-kW PMG-based WECSs with 4.44-kW BUs, when operated under various wind speeds and/or charging and discharging modes of the BUs. Performance results show that the proposed controller is capable of initiating fast and accurate responses to adjust the power generation of the PMG to meet the demands of the generator-side and charging PECs for different wind speeds, and/or charging and discharging of the BUs. These performance features are found to have minor sensitivity to the changes in wind speed, and/or levels of charging the BUs.