Resolution-Level-Controlled WM Inverter for PMG-Based Wind Energy Conversion System

This paper presents the development, implementation, and performance testing of a permanent-magnet generator (PMG)-based wind energy conversion system (WECS) for grid-connected applications. The grid-connected operation is constructed using the new three-phase resolution-level-controlled wavelet-modulated inverter. The output of the wind generator is fed to a switch-mode ac-dc converter, where the dc voltage is controlled to ensure extracting power from the wind under variable wind speed conditions in order to meet the grid active and reactive power demands. The resolution-level control of the grid-side inverter is designed as a current controller for adjusting active and reactive powers delivered to the grid. The proposed WECS is implemented both in software and hardware for performance testing on a direct-drive 6-kW laboratory PMG operated with variable speed. Test results demonstrate that an accurate control of the dc voltage on the generator side ensures adjusting the generator speed to extract power at each wind speed in order to meet the demand active and reactive power delivery to the grid. Also, test results show significant abilities of the resolution-level controller to initiate fast and accurate adjustments in the active and reactive powers delivered to the grid in order to follow any changes in their demand values under variable wind speed.