Typescript, etc. / Digitized by Kansas State University Libraries

Call number: LD2668 .T4 1931 P41

International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / Using a network-based telemetry system places additional requirements on the Radio Frequency (RF) link. Limitations imposed by this link must be considered in advance when designing a network-based telemetry system.

The production and consumption of electricity on the power grid has to balance at all times. Slow balancing, over days and weeks, is governed by the electricity market and carried out through production planning.  Fast balancing, within the operational hour, is carried out by hydropower plants operating in frequency control mode. The need of balancing power is expected to increase as more varying renewable energy production is connected to the grid, and the deregulated electricity market presents a challenge to the frequency control of the grid. The first part of this thesis suggests a method to quantify the need for balancing or energy storage induced by varying renewable energy sources. It is found that for high shares of wind and solar power in the system, the energy storage need over a two-week horizon is almost 20% of the production. The second and third part of the thesis focus on frequency control. In the second part, measurements from three Swedish hydropower plants are compared with the behaviour expected from commonly used power system analysis hydropower models. It is found that backlash in the guide vane and runner regulating mechanisms has a large impact on the frequency control performance of the plants. In the third part of the thesis, the parameters of the primary frequency control in the Nordic grid are optimised with respect to performance, robustness and actuator work. It is found that retuning of the controller parameters can improve the performance and robustness, with a reasonable increase of the actuator work. A floating deadband in the controller is also discussed as a means to improve performance without increasing the actuator work.

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The hovering flight of a micro air vehicle was investigated. Various flight control concepts, inspired by observation of insect and bird flight, were investigated in some detail. The concepts make use of flap frequency or phase between the flap and pitch attitudes of the wing to control the force magnitude. Tilt of the stroke plane or fuselage was used to vector the force. A flight control system was designed for each concept investigated. The investigation has revealed that the preferred control concept is one in which force vectoring is achieved by the fuselage tilt through a shift in the centre of gravity location while the force magnitude is controlled by the phase between pitch and flap attitudes. This has the advantage of reducing the vehicle weight while at the same time relaxing the demand of extremely high frequency actuators. The equations of motion based on a multi-body representation of a flapping wing micro air vehicle were derived and these form the basis for the SIMULINK flight simulation program used to carry out the above investigation. The aerodynamic model used for the simulation was obtained from force measurements with a flapping mechanism that allows the model wing to oscillate with two degrees of freedom (flap and pitch). During these measurements, the phase angle between the flap and pitch angles of the model wing was varied to determine the effects on the force magnitude and direction.

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