scholarly journals A New Grid-Connected Constant Frequency Three-Phase Induction Generator System under Unbalanced-Voltage Conditions

Electronics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 938
Author(s):  
Mohammadreza Moradian ◽  
Jafar Soltani ◽  
Gholam Reza Arab Markadeh ◽  
Hossein Shahinzadeh ◽  
Yassine Amirat
Keyword(s):  
Reactive Power ◽  
Sliding Mode ◽  
Pi Controller ◽  
Induction Generator ◽  
Stator Winding ◽  
Prime Mover ◽  
Generator System ◽  
Constant Frequency ◽  
Pwm Inverter ◽  
Three Phase

This paper presents a new constant frequency, direct grid-connected wind-based induction generator system (IGS). The proposed system includes a six-phase cage rotor with two separate three-phase balanced stator windings and a three-phase SV-PWM inverter which is used as a STATCOM. The first stator winding is connected to the STATCOM and is used to excite the machine. The main frequency of the STATCOM is considered to be constant and equal to the main grid frequency. In the second stator winding, the frequency of the induced emf is equal to the constant frequency, so the generator output frequency is independent of the load power demand and its prime mover speed. The second stator winding is directly connected to the main grid without an intermediate back-to-back converter. In order to regulate the IGS output active and reactive power components, a sliding mode control (SMC) is designed. Assuming unbalanced three-phase voltages for the main grid, a second SMC is developed to remove the machine output’s negative sequence currents. Moreover, a conventional PI controller is used to force the average exchanging active power between the machine and STATCOM to zero. This PI controller generates the reference value of the rotor angular speed. An adjustable speed pitch angle-controlled wind turbine is used as the IGS’s prime mover. The effectiveness and capability of the proposed control scheme have been supported by the simulation results.

scholarly journals An electronic solution for the direct connection of a three-phase induction generator to a single-phase feeder

2009 ◽  
Vol 20 (3) ◽  
pp. 417-426 ◽  
Author(s):  
Ricardo Q. Machado ◽  
Amílcar F. Q. Gonçalves ◽  
Simone Buso ◽  
José A. Pomilio
Keyword(s):  
Power Quality ◽  
Power Flow ◽  
Power Plants ◽  
Single Phase ◽  
Reactive Power ◽  
Induction Generator ◽  
Direct Connection ◽  
Hydro Power ◽  
Pwm Inverter ◽  
Three Phase

This paper proposes a solution for the direct connection of a three-phase induction generator to a single-phase feeder. This high power quality system is intended to be used in micro-hydro power plants applications with control of the water flow. It is employed to maintain the speed of the induction generator greater than its synchronous value. The difference between the generated power and the power consumed by the local load flows through the single-phase feeder. The power flow control is provided by a three-phase PWM inverter that additionally guarantees the local power quality. A system with good power quality must have sinusoidal and constant amplitude voltages, fixed frequency operation, balanced induction generator voltages and currents, harmonics and reactive power compensation. The paper describes the inverter control strategy, presents design criteria of the controllers, and shows experimental results.

Utilization of Self-Excited Three-Phase Induction Generator System

2018 ◽  
Vol 2 (1) ◽  
Author(s):  
Basil Saied ◽  
Hasan Mohammed
Keyword(s):  
Harmonic Distortion ◽  
Active Power ◽  
Modulation Index ◽  
Voltage Source ◽  
Induction Generator ◽  
Switching Frequency ◽  
Prime Mover ◽  
Generator System ◽  
Dc Voltage ◽  
Three Phase

In this paper the analysis of a three phase self-excited induction generator system under transient and steady states with various load conditions are presented. In rare area where assumed no national grid is present, but hydro or wind energy may be available a cheap prime mover, such as micro hydro or wind turbine may be applied, which has fluctuating speed. In order to obtain self-excitation, a voltage source inverter based on sinusoidal pulse width modulation  strategy has been proposed. The generated voltage and frequency are regulated by adjusting modulation index value. The value of modulation index  depends also on the DC voltage level obtained from  batteries or solar panels. The proposed system has been also examined without main dc power source , but with the existence of bank capacitor located at the dc link side of the inverter, in this case  the generated active power should be equal to/or greater than the required active load power. DC chopper load has thus been utilized to absorb the extra active power, this will control the DC voltage across the capacitor while modulation index  will control the system AC  output voltage. The generated voltage waveform contains harmonic orders around and higher than the switching frequency, therefore three-phase high passive filter has been used to eliminate the harmonics effects. As a result the machine terminal voltage and frequency values are regulated and maintained constant for different types of loads at different prime mover speed cases. In all these cases, total harmonic distortion values are within the standard values.

Voltage Control of Single-Phase Two Winding Self Excited Induction Generator Using SVC-MERS for Isolated System

2016 ◽  
Vol 7 (3) ◽  
pp. 901
Author(s):  
Fransisco Danang Wijaya ◽  
Hartanto Prabowo
Keyword(s):  
Single Phase ◽  
Reactive Power ◽  
Voltage Regulation ◽  
Induction Generator ◽  
Prime Mover ◽  
Small Power ◽  
Load Variations ◽  
Three Phase ◽  
Generator Voltage ◽  
Effective Cost

Single-phase induction generator is very suitable to be used in the typical loads which only need a single-phase power supply with small power capacity requirement, such as diesel engine, picohydro or small wind plant. It has some advantages such as rugged, effective cost, maintenance free and require no external excitation. However, it has inductive characteristic which makes poor voltage regulation. This paper proposed a shunt reactive compensator called SVC-MERS which can provide a variable reactive power to maintain the generator voltage despite of load variations. The experiment was conducted on single-phase two winding induction generator coupled by a three-phase induction motor which serves as the prime mover. SVC-MERS and the load are connected in shunt to the main winding, while the excitation capacitor was connected to the auxiliary winding. The experimental results showed that SVC-MERS can improve voltage regulation and substantially enhanced steady state loading limit.

scholarly journals Stochastic Distribution Controller for Wind Turbines with Doubly Fed Induction Generator

2021 ◽  
Author(s):  
Vijayalaxmi Munisamy ◽  
Nayagam Shanmuga Vadivoo ◽  
Vaithilingam Devasena
Keyword(s):  
Reactive Power ◽  
Pi Controller ◽  
Induction Generator ◽  
Doubly Fed Induction Generator ◽  
Major Purpose ◽  
Proportional Integral ◽  
Operating Region ◽  
Doubly Fed ◽  
Grid Side ◽  
Stochastic Distribution

The major purpose of this work is to design the controllers for controlling the variable speed, variable pitch wind turbine (WT) with doubly fed induction generator (DFIG). Vector control strategy is adopted for controlling the DFIG active and reactive power. Generator torque is control to provide the regulated real power with minimum fluctuation. The fixed gain proportional-integral (PI) controller designed to the converter of rotor side and grid side has limited operating range and inherent overshoot. Gain scheduling PI controller is designed to minimize the overshoot and fluctuation exists in proportional-integral controller. Since DFIG based wind energy conversion system (WECS) works in uncertain wind speed, stochastic distribution control (SDC) method is proposed to control the probability distribution function (PDF) of DFIG based WECS. It copes with nonlinearities in the WECS and contiguous variations at operating point and provides satisfactory performance for the whole operating region. It improves the performance together with power quality of generated electric power thereby maximizing the lifespan of installation and ensures secure and acceptable operation of the DFIG based WECS.

scholarly journals Equivalent Sliding Mode Controller for Stability of DC Microgrid

2021 ◽  
Vol 12 (1) ◽  
pp. 23
Author(s):  
Muhammad Rashad ◽  
Uzair Raoof ◽  
Nazam Siddique ◽  
Bilal Ashfaq Ahmed
Keyword(s):  
Reactive Power ◽  
Sliding Mode ◽  
Voltage Regulation ◽  
Pi Controller ◽  
Operating Conditions ◽  
Dc Microgrid ◽  
Dc Microgrids ◽  
Central Controller ◽  
The Stability ◽  
Decentralized Architecture

DC microgrids are gaining popularity due to their lack of reactive power compensation, frequency synchronization, and skin effect problems. However, DC microgrids are not exempted from stability issues. The stability of DC microgrids based on decentralized architecture is presented in this paper. Centralized architecture can degrade system performance and reliability due to the failure of a single central controller. Droop with proportional integral (PI) controller based on decentralized architecture is being used for DC microgrid stability. However, droop control requires a tradeoff between voltage regulation and droop gain. Further, global stability through PI controller cannot be verified and controller parameters cannot be optimized with different operating conditions. To address limitations, an equivalent sliding mode (SM) controller is proposed for a DC microgrid system in this paper. Detailed simulations are carried out, and results are presented, which show the effectiveness of an equivalent SM controller.

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