الفهرس 
Distributed Generation
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Abstract
Recently, the Distributed Generation (DG) give a solution to
the problem of continuously increased power demand in
electrical networks. Microturbine units (MTU) which are
suitable for DG application requirements, have been very
popular for the power consumers because of their flexibility,
compact design and low maintenance.
Different interface systems could be used to link the
MTU with the grid. Examples of these are conventional DCAC converters (inverters), High Frequency Link Converters
(HFLC), Matrix Converters (MC) and back-to-back converters.
Back-to back converters have advantages of controlling the
active and reactive power, ride through faults and elimination
of harmonics at the generator side.
This thesis presents an interface system for a
microturbine unit based on back-to-back converters to operate
in grid connected and islanding modes. Besides regulating the
active power fed from the MTU, during the grid-connected
mode, the proposed interface system regulates the Point of
Common Coupling (PCC) voltage at its rated value. Moreover,
the proposed interface system is controlled to have a Low
Voltage Ride-Through (LVRT) capability by feeding the grid
with reactive power during grid faults. Furthermore, the
proposed interface system keeps the voltage and frequency at
the load terminal during the islanding mode of operation with
the same control structure.
Simulation results are provided to evaluate the dynamic
performance of the proposed MTU interface system at the
different modes of operation. Finally, the proposed interface
system succeeded to transfer between the islanding and the grid
connected modes without overshoots.