Analysis of Grid Connected Dfig with Variation in Generator Speed and Stator Reactive Power Demand Using Reference Power Based Improved Field Oriented Control
D.V.N. Ananth1, G. Joga Rao2

1D.V.N. Ananth, Assistant Professor, Department of EEE, Raghu Educational Society, Visakhapatnam (Andhra Pradesh), India.
2G. Joga Rao, Associate Professor & HOD, Department of EEE, Raghu Educational Society, Visakhapatnam (Andhra Pradesh), India.
Manuscript received on 07 April 2019 | Revised Manuscript received on 20 April 2019 | Manuscript published on 30 April 2019 | PP: 1415-1424 | Volume-8 Issue-6, April 2019 | Retrieval Number: F4012048619/19©BEIESP
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Abstract: In general electrical generators are designed to operate at optimal loads and other operating points to have better efficiency, lesser losses and good voltage regulation. For this the doubly-fed induction generator is also developed in such a way to have better real and reactive power flows, lesser losses and higher productivity. The reactive power supply from the wind power based generators and its associated converters are helpful in improving the profile even under normal operation or under grid faults. The requirement for the reactive power also increases with increase in penetration of these renewable sources or under severe grid faults. In this paper, source and grid side disturbances are analysed such as variable wind speed, rotor speed, and grid reactive power. With any type of disturbance, the DFIG parameters must be stable and to follow the reference parameters. To do so, reference power based improved field oriented control (RPIFOC) scheme is proposed and in this, the stator and rotor reactive powers are controlled based on stator real power value using lookup table technique. The inner control loops also perform faster so as to react with varying disturbances and to follow the desired reference values. For analysis, DFIG parameters like rotor power, grid and stator power, generator speed, stator and rotor currents are considered along with mechanical parameters. The simulation results are done with MATLAB/ SIMULINK.
Keyword: Doubly Fed Induction Generator (DFIG), Wind Energy Conversion System (WECS), Back-to-Back Converter, Reactive Power Control, Maximum Power Extraction, Sub-Synchronous Spee.
Scope of the Article: Smart Grid Communications