Showing papers by "Navid Reza Abjadi published in 2011"

A Novel Isolated Three-Phase Induction Generator with Constant Frequency and Adjustable Output Voltage Using a Three-Phase STATCOM

Abstract: This paper presents a novel isolated three-phase induction generator with constant frequency and adjustable output voltage using a three-phase STATic COMpensator (STATCOM). The proposed electricity generating system consists of a dual stator-winding and STATCOM. In this generator, there are two sets of windings to be embedded in the stator slots. One, referred to as the 3-phase power winding, supplies power to load and the other, called 3-phase excitation winding is connected to a space vector modulation (SVM) voltage source invertor (VSI). Due to magnetic coupling between stator windings, active power transfer occurs between them. This active power causes serious disturbance in generator performance. A closed-loop controller for STATCOM is used to supply only requested reactive power and prevent active power transfer. In this paper, a hydraulic turbine and its governing system used for controlling requested active power amount by load are modelled. In comparison with other isolated induction generators, important advantages of this one are constant frequency independent from prime mover speed and adjustable output voltage.

Improvement in speed control of a six-phase induction motor using fuzzy control and genetic algorithm

Abstract: This paper presents an application of a self tuning fuzzy control technique for speed control of a six-phase induction motor (SPIM) The torque ripple of a SPIM is lower than a three-phase IM This paper proposes a rotor flux-oriented control technique for a SPIM to decouple torque and flux control Using the genetic algorithm (GA) with a simple cost function for tuning of the fuzzy controller parameters, a perfect speed control for SPIM is achieved

Increasing the Stability of Power Systems by Simultaneous Design of PSS and TCSC through the PSO Technique

Abstract: In large power systems, damping of inter-area oscillation is of great importance for secure operation of the system. Yet, sole use of traditional stabilizers of power systems cannot provide inter-area oscillations with a suitable damping. To that end, FACT damping controllers of power oscillations are available for providing suitable damping for these modes. In this report, the application of PSO for simultaneous design of PSS and TCSC controllers to increase the power system stabilization is demonstrated. The problem of simultaneous design of PSS and TCSC controllers is presented as an optimization problem based on the time domain. Here, the type ST1A excitation system is used. The PSO algorithm is applied in order to search controlling parameters and, by minimizing the objective function based on the time domain comprising the deviation of swing-out rotor speed, it optimizes the system stability.

Flux and torque control of synchronous reluctance motor based on second order sliding mode method

Abstract: In this paper the electromagnetic torque and the square of the stator flux magnitude control using second order sliding mode controller (2-SMC) of a synchronous reluctance motor (SynRM), is proposed. With the purpose of guarantee the electromagnetic torque and stator flux to track its reference signal strictly, the electromagnetic torque sliding mode variable and stator flux sliding mode variable were selected separately. Designed super twisting controller permits to decrease chattering that is inherent in first order sliding mode control and to improve accuracy. Also the upper band of parameters uncertainties, are calculated to serve the stability of the total system. The effectiveness of the designed control scheme is confirmed via simulation.