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In this work it is presented a two-phase open-end winding induction motor (IM) driven by an improved current source inverter (CSI). The proposed inverter has independent full quadrant operation, lower DC-link current value, high magnetics power density, 25% more efficient and high AC output voltage waveform quality compared to conventional CSI solutions. A back-to-back AC-DC-AC current source converter...
The purpose of the paper is to investigate the application of a Switched Reluctance Generator (SRG) for future wave energy converters. This machine presents some favourable features as compared to others. The machine optimal operation can be obtained after a detailed assessment of the control strategy. For this purpose, a SRG model is implemented in Matlab® Simulink® environment to find out the values...
This paper proposes a methodology to efficiently estimate the probability of small-disturbance rotor angle instability of uncertain power systems. Traditional Monte Carlo (MC) approaches are computationally intensive and inefficient, particularly when used to study low probability conditions which result in small disturbance instabilities and develop into serious outage events high impact. The proposed...
This paper compares the effects of ring, radial and interconnected DC grid topologies on the transient stability of a segmented 15 - bus electric grid for different HVDC schemes. For this purpose, three HVDC convertor technologies and four HVDC station configurations are considered. A three phase AC bus fault is applied and the rotor angle disturbance is analyzed. The results show that the transient...
This paper investigates the effect of two HVDC grid segmentation topologies i.e. hybrid HVAC-HVDC and standalone HVDC on the transient stability of a 15-bus electric grid. For this purpose, four HVDC station configurations and three HVDC technologies are considered. A three phase AC fault is applied at one of the buses and the rotor angle of one of the generators is analyzed. The results show that...
Wind power is the fastest growing source of electrical energy in the world today due to the increasing awareness of the environmental problems together with the rapid increase in the fuel cost and the power demand. Wind energy conversion using Doubly Fed Induction Generator (DFIG) is one of the most important types of renewable energy generations. The wind farm power output has large fluctuations...
The double-fed inductor generator (DFIG) is one important type of wind generator. Because of high percentage of wind energy, it is necessary to build accurate wind generator model and parameters for power system electro-mechanic simulation. The paper mainly presents the simulation model and parameter identification method of DFIG type wind generators. For power system transient simulation, the characteristic...
In this paper, a nonlinear speed control scheme which combines nonlinear optimal controller, nonlinear disturbance observer and adaptive kalman filter is proposed for Magnetically Suspend Flywheel (MSFW). Firstly, in order to improve the dynamic and steady-stage performances of motor driving system, the state feedback exact linearization model of BUCK converter is derived, and a nonlinear optimal...
This paper presents the thermal feasibility study of rotary converter generation systems (RCGS) which solve maintenance problem as wear of brush of slip rings of doubly-fed induction generators. The total structure of RCGS is revealed. The thermal analysis of the structure is conducted. The analytical result shows the structure fulfills the thermal limits of RCGS components under 5MW rated conditions...
In this paper consumption of electrical power for heavy duty induction motors is taken into consideration. These electric drives are present in open pit mine Suvodol, which is feeding power plant station of REK Bitola with power of 3×232 MW. For these types of motor drives, 6 kV wound rotor induction motors are used. Intention of the authors is to comment power consumption and to propose techniques...
A different topology for brushless doubly-fed induction generators is presented. A power conditioning system is mounted onto two coaxially connected wound rotors. Carbon brushes and slip rings are replaced by the wound rotors and the rotor-mounted power condition system, which bi-directionally exchanges power to the grid with appropriate amplitude and phase difference between the voltages applied...
This paper focuses on the development of maximum wind power extraction algorithms for variable speed wind power generation systems. A review of different maximum wind power extraction algorithms is presented in this paper, based on which an intelligent maximum power extraction algorithm is developed to improve the system performance and to facilitate the control implementation. As an integral part...
This paper presents a comprehensive design and implementation of a DFIG (Doubly Fed Induction Generator) for a micro-level WECS (Wind Energy Conversion System). The design is carried out for a 3.7 kW doubly fed induction machine with the reduced power conditioning circuit requirements. The control algorithm is implemented using a DSP (Digital Signal Processor). The GSC (Grid-Side Converter) is controlled...
This paper presents control strategies for the integration of a grid-connected wind-photovoltaic hybrid system via adaptation converters connected to a common DC bus. For both wind and solar system, adequate control algorithms have been implemented for the maximum power extraction. The grid side converter has been connected to the point of common coupling (PPC) through an RL filter. The control of...
Depending on the rotor magnet and stator winding configurations, the magnitude of the resulting flux-linkage harmonics in permanent-magnet (PM) motor drives can be substantial. The flux-linkage harmonics result into dc-link current harmonics that can cause the operation of certain track circuits (used to identify the presence of a train on a track section) to malfunction. Predicting the impact of...
This paper presents a new method for increasing the doubly fed induction generator (DFIG) performance under fault conditions. After the fault takes place, the rotor current increases to more than 8 times the nominal value, so the protective resistors called crowbar (Cb) will be switched on, and the current will be restricted. In order to stop injuring the rotor side convertor (RSC), the control signals...
The traditional control strategies of the permanent magnet synchronous generator (PMSG) based on rotor flux orientation have unconquerable drawbacks, such as the reactive power exchange by the id=0 control and the complicated calculation by the unity power factor (UPF) control. A novel UPF control strategy of the PMSG using stator flux orientation is proposed in this paper. The simulation results...
The fault ride-through ability of doubly fed wind generators (DFIG) has got more and more attention. New grid codes for interconnection of wind turbines required that wind turbines remain connected to the grid and actively contribute to the system stability during and after grid faults. Uninterrupted excitation of DFIG can both avoid running over-speed of wind turbines during grid faults and accelerate...
The fast development of wind power generation brings new necessary requirement for wind turbine to provide Low Voltage Ride-Through (LVRT) capability. The paper introduces the models of Doubly Fed Induction Generator (DFIG), converter and rotor active crowbar, and analyses characteristics of DFIG system with rotor active crowbar during grid voltage dip. A novel turn-on and turn-off control method...
This paper introduces a new solution for Doubly-Fed Induction Generators (DFIG) to stay connected to the grid during short circuit condition. The main idea is to increase the stator voltage to a level that creates the required flux to keep the rotor side converter current below its transient rating. To accomplish this goal, a series compensator is added to inject voltage, during the short circuit,...
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