Frequency swept fibre laser for wind speed measurements

Publication: ResearchPh.D. thesis – Annual report year: 2012

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Frequency swept fibre laser for wind speed measurements. / Pedersen, Anders Tegtmeier; Lindelöw-Marsden, Petter (Supervisor); Rottwitt, Karsten (Supervisor).

DTU Fotonik, 2012. 147 p.

Publication: ResearchPh.D. thesis – Annual report year: 2012

Harvard

Pedersen, AT, Lindelöw-Marsden, P & Rottwitt, K 2012, Frequency swept fibre laser for wind speed measurements. Ph.D. thesis, DTU Fotonik.

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Author

Pedersen, Anders Tegtmeier; Lindelöw-Marsden, Petter (Supervisor); Rottwitt, Karsten (Supervisor) / Frequency swept fibre laser for wind speed measurements.

DTU Fotonik, 2012. 147 p.

Publication: ResearchPh.D. thesis – Annual report year: 2012

Bibtex

@book{723e53af4f45472fbfc81fc2c777097a,
title = "Frequency swept fibre laser for wind speed measurements",
publisher = "DTU Fotonik",
author = "Pedersen, {Anders Tegtmeier} and Petter Lindelöw-Marsden and Karsten Rottwitt",
year = "2012",

}

RIS

TY - BOOK

T1 - Frequency swept fibre laser for wind speed measurements

A1 - Pedersen,Anders Tegtmeier

AU - Pedersen,Anders Tegtmeier

A2 - Lindelöw-Marsden,Petter

A2 - Rottwitt,Karsten

ED - Lindelöw-Marsden,Petter

ED - Rottwitt,Karsten

PB - DTU Fotonik

PY - 2012

Y1 - 2012

N2 - This PhD thesis builds around a light source forming the basis for a novel type of wind measuring lidar. The lidar emits a train of laser pulses with each pulse being separated from its neighbours in frequency, while being closely spaced in time, thus combining the advantages of conventional continuous wave (CW) and pulsed lidars. A light source capable of emitting such a pulse train is suggested. A theoretical description of all components constituting the light source is presented, and a time dependent model is developed and compared to measurements as well as to previous theoretical work from the scientific<br/>literature. The model presented shows good agreement with the experimental results regarding the pulse train envelope as well as the individual pulses. A model adopted from the literature is subsequently expanded to incorporate frequency components other than the main signal frequency and compared to measurements of individual pulse spectra. Critical issues such as various contributions to noise, in particular amplified spontaneous emission (ASE), are investigated. The realized frequency stepped pulse train (FSPT) emitting light source has been incorporated into a modified CW lidar, and the ability to measure wind speeds as well as the direction successfully demonstrated. A challenge still remains in the improvement of the signal to noise ratio (SNR), though. Additionally, a theoretical study of the feasibility of mounting lidars in the blades of wind turbines for active pitch angle control has been undertaken with a positive outcome encouraging an experimental trial to measure wind with a such construction. Therefore, a small telescope CW lidar designed for turbine blade integration has been tested in a high performance wind tunnel, and very good agreement with reference measurements<br/>has been obtained.

AB - This PhD thesis builds around a light source forming the basis for a novel type of wind measuring lidar. The lidar emits a train of laser pulses with each pulse being separated from its neighbours in frequency, while being closely spaced in time, thus combining the advantages of conventional continuous wave (CW) and pulsed lidars. A light source capable of emitting such a pulse train is suggested. A theoretical description of all components constituting the light source is presented, and a time dependent model is developed and compared to measurements as well as to previous theoretical work from the scientific<br/>literature. The model presented shows good agreement with the experimental results regarding the pulse train envelope as well as the individual pulses. A model adopted from the literature is subsequently expanded to incorporate frequency components other than the main signal frequency and compared to measurements of individual pulse spectra. Critical issues such as various contributions to noise, in particular amplified spontaneous emission (ASE), are investigated. The realized frequency stepped pulse train (FSPT) emitting light source has been incorporated into a modified CW lidar, and the ability to measure wind speeds as well as the direction successfully demonstrated. A challenge still remains in the improvement of the signal to noise ratio (SNR), though. Additionally, a theoretical study of the feasibility of mounting lidars in the blades of wind turbines for active pitch angle control has been undertaken with a positive outcome encouraging an experimental trial to measure wind with a such construction. Therefore, a small telescope CW lidar designed for turbine blade integration has been tested in a high performance wind tunnel, and very good agreement with reference measurements<br/>has been obtained.

BT - Frequency swept fibre laser for wind speed measurements

ER -