Wind Turbine Driven Induction Generator Research Articles

Modeling and Simulation of a Wind Turbine Driven Induction Generator Using Bond Graph

The objective of this paper is to investigate the modelling and simulation of wind turbine applied on induction generator with bond graph methodology as a graphical and multi domain approach. They provide a precise and unambiguous modelling tool, which allows for the specification of hierarchical physical structures. The paper begins with an introduction to the bond graphs technique, followed by an implementation of the wind turbine model. Simulation results illustrate the simplified system response obtained using the 20-sim software.

Self-excitation system for control of wind turbine driven induction generator using direct torque control

This paper describes the direct torque and flux control (DTC) of a self-excited induction generator (SEIG) for wind energy conversion systems (WECS). The DTC-based WECS is more suitable for low power applications, owing to several advantages such as good torque control in steady-state and transient operating conditions, not requiring an accurate generator model, the absence of coordinate transforms and current controllers. The SEIG is excited by a voltage source converter (VSC) with a capacitor and start-up battery on the direct current (DC) side. The required reactive power for the SEIG is provided by the capacitor. The terminal voltage of the SEIG varies with wind speed and load conditions. The proposed DTC strategy is used to control the terminal voltage of the SEIG and DC voltage at a constant value when the load and wind speed are varied. The gate signals for the VSC are derived from an inverter switching table. The torque and stator flux of the induction generator are controlled through the voltage space vector selection. The proposed system gives good dynamic and steady-state performance. The effectiveness of the proposed control strategy is verified through simulations. Experimental results are presented to validate the simulation results.

Hybrid, open-loop excitation system for a wind turbine-driven stand-alone induction generator

This study proposes a hybrid, open-loop exciter for the wind turbine-driven induction generator for low power applications. The hybrid exciter comprises one set of fixed capacitor bank and a parallel connected three-phase fixed frequency pulse width modulation (PWM) inverter fed from a battery. This hybrid exciter inherently adapts to the changes in the rotor speed or load on the generator while maintaining a near constant voltage and frequency at the load terminals. The whole system including the PWM inverter is operated in an open loop, without the need for any sensors other than the low-speed cut-in and high-speed cut-out mechanisms on the wind turbine. Results from simulations and laboratory tests show that the dynamic reactive power compensation of the generator is inherent in the proposed open-loop system. The volt ampere (VA) rating of the inverter and the battery capacity can be minimal, depending only upon the speed and load ranges of the generator and the choice of fixed capacitor var.

Performance of a grid-connected wind generation system with a robust susceptance controller

Wind turbine driven induction generators are vulnerable to transient disturbances like wind gusts and low voltages on the system. The fixed capacitor at the generator terminal or the limited support from the grid may not be able to provide the requisite reactive power under these abnormal conditions. This paper presents a susceptance control strategy for a variable speed wound-rotor induction generator which can cater for the reactive power requirement. The susceptance is adjusted through a robust feedback controller included in the terminal voltage driven automatic excitation control circuit. The fixed parameter robust controller design is carried out in frequency domain using multiplicative uncertainty modeling and H ∞ norms. The robustness of the controller has been evaluated through optimally tuned PID controllers. Simulation results show that the robust controller can effectively restore normal operation following emergencies like sudden load changes, wind gusts and low voltage conditions. The proposed robust controller has been shown to have adequate fault ride through capabilities in order to be able to meet connection requirements defined by transmission system operators.

Dynamic Performance Enhancement of Agrid-Connected Wind Generation System

The recent trend of large wind power penetration to grid systems can be potentially troublesome in terms of dynamic performance of the system. In the absence of adequate control actions, the generators may have to be removed from the grid sometimes even for not so large changes in the wind system. This paper analyses the dynamic performance of a variable-speed wind turbine-driven cage generator connected to the grid system. It has been observed that a variable susceptance excitation controller at the generator terminals can control unusually large voltage as well as frequency swings arising from wind-gust conditions and system faults. Additional Proportional and Integral (PI) and Proportional, Integral and Derivative (PID) controls of thyristor angles in the susceptance control circuit were tested for dynamic performance improvement of the wind turbine-driven induction generator system. The variable susceptance excitation scheme with auxiliary PID control was observed to provide very good transient performance.