الفهرس | Only 14 pages are availabe for public view |
Abstract Nowadays direct drive variable speed wind energy conversion system (WECS) are increasing rapidly due to the proper performance and the better reliability than the geared drives. In direct drive WECS, the generator is either permanent magnet synchronous generator (PMSG) or electrically excited synchronous generator (EESG). Both generators have advantages and disadvantages. Faced with the increase in installed wind power and the mandatory need to preserve the stability of the electricity grid, the grid operators have warned about the enormous importance of the behavior of the wind generators when connected to the grid. Consequently, grid operators around the world issue grid codes. These grid codes asking the wind turbines manufacturers for several issues to be considered for connection the wind farm to the grid. These issues including active power control, reactive power control, voltage stability, design voltages and frequencies, power quality issues and low Voltage Ride Through (LVRT) capability. To fulfill those requirements, different control techniques have been proposed for each WECS |