Grid tied inverter for direct drive PMSG based wind energy conversion system

This proposed work discusses about the grid tied inverter for wind energy conversion system with a direct drive permanent magnet synchronous generator (PMSG) based variable speed wind turbine. Output voltage varies both in frequency and magnitude during variable-speed operation, due to this, dc-link voltage changes in an uncontrolled manner. By interfacing Inverter unit dc-link voltage is controlled which was referred to as Grid Tie Inverter (GTI). It is a power inverter that converts the direct current (DC) into alternating current (AC) with an ability to synchronise to interface with a utility. The gate pulses of the grid tie inverter are generated by comparing the grid voltage taken as a reference signal with a carrier signal. Here, grid tie inverter output voltage is changed corresponding to the grid voltage. If the Turbine rotates below the cut in speed, wind generator generates power below the rated level. In this time, the dc-link capacitor generates the reactive power which is supplied to the grid. Continuous supply to the grid is achieved which was considered as major objective.