Masters Theses


Murali Bottu


"As a result of wind speed intermittency, wind turbine output power can be highly variable. The large variability in output power can adversely impact local loads that are sensitive to pulsating power. To mitigate large swings in power, the wind turbine output power can be smoothed by using a small energy buffer. A power conditioner is proposed to smooth the wind power output by utilizing the energy of an ultracapacitor. The conditioner is based on a single phase voltage source inverter (VSI) connected between the grid interconnection point and the ultracapacitor. The shunt VSI injects or absorbs active power from the line to smooth the wind power output by utilizing the short term storage capabilities of the ultracapacitor. The ultracapacitor is connected to the DC link through a DC-DC converter. The bidirectional DC-DC converter acts in buck mode during discharge and in boost mode during charging to maintain the voltage of the DC link relatively constant to provide good controllability of the VSI. The control strategies for the conditioner are presented in this thesis. The simulation results show that the power quality conditioner is efficient in smoothing the wind power. To understand how effectively the power conditioner smoothes [sic] the wind turbine output in real time operational conditions, a hardware prototype for verification is developed in addition to software simulation. The bidirectional DC-DC converter and VSI are constructed and tested in the laboratory and then field tested. The control of the bidirectional DC-DC converter is implemented using the microchip PIC24FJ128GA010 microcontroller. The gate signals for the IGBTs in the VSI are obtained from the TI TMDSDOCK28335 digital signal controller. The conditioner design and control are validated on a Skystream 3.7 wind turbine installed at Missouri University of Science & Technology"--Abstract, page iii.


Crow, Mariesa

Committee Member(s)

Chowdhury, Badrul H.
Ferdowsi, Mehdi


Electrical and Computer Engineering

Degree Name

M.S. in Electrical Engineering


Sandia Laboratories


Missouri University of Science and Technology

Publication Date

Spring 2011


x, 54 pages


© 2011 Murali Bottu, All rights reserved.

Document Type

Thesis - Open Access

File Type




Subject Headings

Energy storage
Wind power
Wind turbines -- Design and construction

Thesis Number

T 9805

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