Functional observer design with application to pre-compensated multi-variable systems

, Article 2015 IEEE Conference on Control and Applications, CCA 2015 - Proceedings, 21 September 2015 through 23 September 2015 ; 2015 , Pages 620-625 ; 9781479977871 (ISBN) Nazmi, S ; Mohajerpoor, R ; Abdi, H ; Nahavandi, S ; Sharif University of Technology

Institute of Electrical and Electronics Engineers Inc 2015

Abstract

Partial state estimation of dynamical systems provides significant advantages in practical applications. Likewise, pre-compensator design for multi variable systems invokes considerable increase in the order of the original system. Hence, applying functional observer to pre-compensated systems can result in lower computational costs and more practicability in some applications such as fault diagnosis and output feedback control of these systems. In this note, functional observer design is investigated for pre-compensated systems. A lower order pre-compensator is designed based on a H2 norm optimization that is designed as the solution of a set of linear matrix inequalities (LMIs). Next, a...

Low Order Pre-compensator Design Using Linear Matrix Inequalities

, M.Sc. Thesis Sharif University of Technology Nazmi, Shabnam (Author) ; Nobakhti, Amin (Supervisor) ; Thornhill, Nina (Co-Advisor)

Abstract

One of the most common problems encountered in multivariable systems is the interactions between the system inputs and outputs. Interaction causes difficulties in control of these systems. Hence reduction of interaction in multivariable systems is an important design objective. One way to do this is to employ a pre-compensator in the open loop systems. Several approaches with different design methods and optimization criterions have been proposed thus far. In this study the problem of interaction reduction for a square stable system is considered and a pre-compensator matrix is designed which reduces interactions in the interacting multivariable system.In this case the purpose is to use...

Modeling and Simulation of Hydro-Power Station and Determination and Evaluation of Governor Design Specifications

, M.Sc. Thesis Sharif University of Technology Amir Nazmi Afshar, Peyman (Author) ; Durali, Mohammad (Supervisor)

Abstract

The main objective of this project is to take the first steps in designing power plants governor in Iran. In this work, we obtain a realistic model of a hydro-power plant including hydraulic characteristics from the dam to the outlet tail water, mechanically including: the turbine, the gates and all mechanical and dynamic parts, and electrically including generators, transformers and the consumption network. The model is used to simulate different working modes of turbine operation. The Bond Graph method is used for deriving the system equations and MATLAB software for simulations. A conceptual design of the governor is done and the governor model is combined with the turbine model. Using...

Starting improvement of micro-wind turbines operating in low wind speed regions

, Article International Journal of Green Energy ; Volume 14, Issue 11 , 2017 , Pages 868-877 ; 15435075 (ISSN) Amir Nazmi Afshar, P ; Gooya, M ; Hosseini, S. V ; Pourrajabian, A ; Sharif University of Technology

2017

Abstract

The study deals with the design and optimization of external and internal geometry of micro-wind turbines blades. A specified objective function which consists of the power coefficient and the starting time was defined and the genetic algorithm optimization technique in conjunction with the blade-element momentum theory was adopted to find the geometry of the blades including the distributions of the chord, the twist angle and also the shell thickness. Moreover, the allowable stress of the blades was considered as a constraint to the objective function. Results show that a reasonable compromise is achievable such that the starting time of the blades reduces noticeably in return for a small...

Hollow blades for small wind turbines operating at high atitudes

, Article Journal of Solar Energy Engineering, Transactions of the ASME ; Volume 138, Issue 6 , 2016 ; 01996231 (ISSN) Pourrajabian, A ; Amir Nazmi Afshar, P ; Mirzaei, M ; Ebrahimi, R ; Wood, D. H ; Sharif University of Technology

American Society of Mechanical Engineers (ASME) 2016

Abstract

Since the air density reduces as altitude increases, operation of small wind turbines (SWTs), which usually have no pitch adjustment, remains challenging at high altitudes due largely to the reduction of starting aerodynamic torque. By reducing the moment of inertia through the use of hollow blades, this study aims to speed up the starting while maintaining the structural integrity of the blades and high output power. A horizontal axis turbine with hollow blades was designed for two sites in Iran with altitude of 500 m and 3000 m. The design variables are the distributions of the chord, twist, and shell thickness and the improvement of output power and starting are the design goals....