Application of linear parameter varying control synthesis in power systems

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Qiu, Wenzheng
Major Professor
Vijay Vittal
Mustafa Khammash
Committee Member
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Electrical and Computer Engineering

In this dissertation, the application of linear parameter varying synthesis to power system controller design is investigated. The study is motivated by the inevitable limitation of a LTI controller on the nonlinear power systems in a large operating range and successful implementation of this approach in safety critical systems like aircrafts and process control. The main goal is to apply the LPV techniques to the Power System Stabilizer synthesis.;The LPV model for power systems is developed. A systematic procedure to design PSS using LPV synthesis is presented. The feedback setup is constructed and a general guideline for proper weighting function selection is provided. Both Single Quadratic Lyapunov Function based LPV synthesis and Parameter Dependent Lyapunov Function based LPV synthesis are studied. Comparisons are made with the conventionally designed PSS and the H infinity optimal PSS. The LPV PSS is found to be more effective.;Inspired by the characteristic of a LPV controller, that it guarantees system stability and performance for arbitrarily fast changing scheduling parameters on a predefined range, further work is done on the application of LPV methods to decentralized PSS design. The design framework and procedure are given. By taking generator real and reactive power as scheduling variables, the generator is decoupled from the rest of the system. The design for a given PSS is independent of the design of the others and all the PSSs cooperate with each other automatically. The decoupling also leads to a relatively low order PSS design. The numerical examples further illustrate that LPV approach is useful for designing decentralized controllers in power systems.;The nonlinear simulations show that these independently designed decentralized PSSs co-operate well in a wide operating range and have better damping characteristics than conventionally designed PSSs. The disturbances tested have been selected to be different in nature and are at different locations. The performance of the LPV PSSs is superior to the conventionally designed PSSs. A theoretical proof for stability is given for the decentralized controller design. The primary results from this research clearly demonstrate the great potential of LPV synthesis application in power systems.

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Thu Jan 01 00:00:00 UTC 2004