scholarly journals A low-cost ac-dc rectifier for variable-speed wind energy conversion systems

2021 ◽  
Author(s):  
Zhenhan. Luo
Keyword(s):  
Control System ◽  
Low Cost ◽  
Synchronous Generator ◽  
Voltage Source ◽  
Current Loop ◽  
Variable Speed ◽  
Synchronous Generators ◽  
Wind Turbine System ◽  
Synchronous Reference Frame ◽  
Energy Conversion Systems

In this thesis, a novel AC-DC rectifier is adopted to convert the variable AC voltages from wind generator to a constant dc-link voltage. A DC-AC inverter is used to transfer the energy to fixed ac grid as well as maintain dc-link voltage constant. The rectifier is connected to the generator, which has two sets of three-phase windings. Electrical exited or permanent magnetic synchronous generators are suitable for this rectifier. The AC-DC rectifier features low cost, low power losses and simple control structure. The major content of this thesis consists of four parts. The first part investigates the operation of the AC-DC rectifier. The analysis illustrates the current paths in the rectifier and the remarkable voltage-boosting capability. A simulation model of the converter is built and verified. The second part models the synchronous generator with two sets of windings. The model is developed in the d-q synchronous reference frame. The simulation results from the model are verified by the experimental results.Then the third part is the design of the control system, which involves the generator, the AC-DC rectifier and constant dc-link voltage source. The control system composites of the inner current loop and the outer speed loop. The control system achieves the variable-speed operation of the generator and the regulation of the dc-link current. Finally, a prototype of wind turbine system is established in the lab to verify the analysis of rectifier, synchronous generator and control system design. The steady-state and transient responses of the wind system are compared. Simulation and experiment verify the analysis in this thesis.

scholarly journals A low-cost ac-dc rectifier for variable-speed wind energy conversion systems

2021 ◽  
Author(s):  
Zhenhan. Luo
Keyword(s):  
Control System ◽  
Low Cost ◽  
Synchronous Generator ◽  
Voltage Source ◽  
Current Loop ◽  
Variable Speed ◽  
Synchronous Generators ◽  
Wind Turbine System ◽  
Synchronous Reference Frame ◽  
Energy Conversion Systems

In this thesis, a novel AC-DC rectifier is adopted to convert the variable AC voltages from wind generator to a constant dc-link voltage. A DC-AC inverter is used to transfer the energy to fixed ac grid as well as maintain dc-link voltage constant. The rectifier is connected to the generator, which has two sets of three-phase windings. Electrical exited or permanent magnetic synchronous generators are suitable for this rectifier. The AC-DC rectifier features low cost, low power losses and simple control structure. The major content of this thesis consists of four parts. The first part investigates the operation of the AC-DC rectifier. The analysis illustrates the current paths in the rectifier and the remarkable voltage-boosting capability. A simulation model of the converter is built and verified. The second part models the synchronous generator with two sets of windings. The model is developed in the d-q synchronous reference frame. The simulation results from the model are verified by the experimental results.Then the third part is the design of the control system, which involves the generator, the AC-DC rectifier and constant dc-link voltage source. The control system composites of the inner current loop and the outer speed loop. The control system achieves the variable-speed operation of the generator and the regulation of the dc-link current. Finally, a prototype of wind turbine system is established in the lab to verify the analysis of rectifier, synchronous generator and control system design. The steady-state and transient responses of the wind system are compared. Simulation and experiment verify the analysis in this thesis.

The Control and Model of Synchronous Generator on Ship

2012 ◽  
Vol 195-196 ◽  
pp. 1095-1101
Author(s):  
Le Luo ◽  
Lan Gao ◽  
Liang Chen ◽  
Liang Hu
Keyword(s):  
Mathematical Model ◽  
Control System ◽  
Simulation Model ◽  
Synchronous Generator ◽  
Excitation Control ◽  
Synchronous Generators ◽  
Simulation Test ◽  
Power Station ◽  
Model And Simulation ◽  
The Mathematical Model

This paper analyzes the characteristics of marine power station. The mathematical model and simulation model of synchronous generators AVR+PSS excitation control system was built. At last the simulation test of suddenly add load was did in MATLAB/simulink environment. The result shows that the excitation control system has well stability, rapidity and some robustness.

A Comparative Analysis of Three-Phase, Multi-Phase and Dual Stator Axial Flux Permanent Magnet Synchronous Generator for Vertical Axis Wind Turbine

2013 ◽  
Vol 446-447 ◽  
pp. 709-715 ◽  
Author(s):  
M. Shahrukh Adnan Khan ◽  
Rajprasad K. Rajkumar ◽  
Rajparthiban K. Rajkumar ◽  
C.V. Aravind
Keyword(s):  
Wind Turbine ◽  
Permanent Magnet ◽  
Synchronous Generator ◽  
Vertical Axis ◽  
Vertical Axis Wind Turbine ◽  
Synchronous Generators ◽  
Permanent Magnet Synchronous Generators ◽  
Wind Turbine System ◽  
Three Phase ◽  
Multi Phase

In this paper, the performances of all the three kinds of Axial type Multi-Pole Permanent Magnet Synchronous Generators (PMSG) namely Three-phase, Multi-phase or Five Phase and Double Stator fixed in Vertical Axis Wind Turbine (VAWT) were investigated and compared in order to get an optimal system. MATLAB/Simulink had been used to model and simulate the wind turbine system together with all the three types Permanent Magnet Generators. It was observed from the result that with the increasing number of pole in both low and high wind speed, the five phase generator produced more power than the other two generators. In general, it was observed that the responses of the Multi-phase generator at both high and low speed wind showed promising aspect towards the system followed by Dual Stator. But with the change of the variables such as wind velocity, turbine height, radius, area together with the generator pole pairs and stator resistance, the optimum system should be chosen by considering the trade-off between different configurations which were firmly analyzed and described in this paper.

scholarly journals Droop-free controls of inverter-based generator for use in systems that interconnected with synchronous generators

2021 ◽  
Vol 12 (2) ◽  
pp. 765
Author(s):  
Suchart Janjornmanit ◽  
Sakorn Panta ◽  
Wirat Nakkrongdee
Keyword(s):  
Synchronous Generator ◽  
Active Power ◽  
Control Technique ◽  
Voltage Source ◽  
Frequency Change ◽  
Droop Control ◽  
Synchronous Generators ◽  
Voltage Source Inverters ◽  
Autonomous Operation ◽  
The Stability

Because of its simplicity and autonomous operation, droop control technique is widely implemented for power generation control in microgrids. Despite its popularity, it has been reported that the technique has the stability problem. In this paper, the previous work of droop-free inverter-based generator designed for operating in a fix frequency islanded microgrid, is redesigned to have the ability to operate in both islanded and grid connected microgrid as well as to the main power grid where it interconnected with synchronous generators. The proposed voltage source inverters use phase locked loop(PLL) algorithm to synchronize the changing frequency due to the operation of the synchronous generator. Unlike the frequency droop control that the output frequency is varied as its active power changed, the proposed controls do not make an adjustment of the system frequency. This kind of operation reduces the chance of the system unstable due to severe frequency change and it also reduces the frequency deviation when it increases its active power output. Simulation and result of the meshed power network demonstrate the feasibility to implement the proposed controls in thereal system.

scholarly journals Synchronous Generators Modeling and Control Using the Framework of Individual Channel Analysis and Design: Part 1

2007 ◽  
Vol 8 (5) ◽  
Author(s):  
Carlos Ernesto Ugalde Loo ◽  
Luigi Vanfretti ◽  
Eduardo Liceaga-Castro ◽  
Enrique Acha
Keyword(s):  
Control System ◽  
System Analysis ◽  
Block Diagram ◽  
Synchronous Generator ◽  
Careful Analysis ◽  
Operating Conditions ◽  
Synchronous Generators ◽  
Modeling And Control ◽  
Analysis And Design ◽  
Channel Analysis

In this paper a comprehensive dynamical assessment of a high order synchronous generator plant is carried out using the Individual Channel Analysis and Design (ICAD) framework –a multivariable control engineering tool that allows robustness and system performance evaluations. The great benefits of ICAD are elucidated and contrasted to those provided by the long-time honored block diagram representations. Several models used for the small signal stability analysis of synchronous generators are evaluated under the framework of ICAD. The study, which builds on pioneering work, reveals the great advantages of carrying out control system analysis and design with higher order generator models. Moreover, careful analysis of the ICAD's Multivariable Structure Function (MSF) helps to explain, formally, why some operating conditions of the control system are more critical than others. Furthermore, correct interpretations of MSFs are amenable to robust and stable control system designs. Two kinds of studies are considered in the paper; one assesses operation under various power factor conditions and the other under a varying tie-line reactance. The control system design and stability and structural robustness assessment of the system are presented in the second part of this paper. Moreover, results obtained under the ICAD framework are compared with those arising from conventional controllers.

scholarly journals Development of a brushless HTS exciter for a 10 kW HTS synchronous generator

2021 ◽  
Author(s):  
Christopher Bumby ◽  
Rodney Badcock ◽  
HJ Sung ◽  
KM Kim ◽  
Zhenan Jiang ◽  
...  
Keyword(s):  
Thermal Load ◽  
Synchronous Generator ◽  
Internal Resistance ◽  
Voltage Source ◽  
Synchronous Generators ◽  
Thermal Bridge ◽  
Current Leads ◽  
Experimental Laboratory ◽  
Laboratory Device ◽  
Dc Current

HTS synchronous generators, in which the rotor coils are wound from high-Tc superconducting wire, are exciting attention due to their potential to deliver very high torque and power densities. However, injection of the large DC currents required by the HTS rotor coils presents a technical challenge. In this paper we discuss the development of a brushless HTS exciter which operates across the cryostat wall to inject a superconducting DC current into the rotor coil circuit. This approach fundamentally alters the thermal load upon the cryogenic system by removing the need for thermally inefficient normal-conducting current leads. We report results from an experimental laboratory device and show that it operates as a constant voltage source with an effective internal resistance. We then discuss the design of a prototype HTS-PM exciter based on our experimental device, and describe its integration with a demonstration HTS generator. This 200 RPM, 10 kW synchronous generator comprises eight double pancake HTS rotor coils which are operated at 30 K, and are energised to 1.5 T field through the injection of 85 A per pole. We show how this excitation can be achieved using an HTS-PM exciter consisting of 12 stator poles of 12 mm YBCO coated-conductor wire and an external permanent magnet rotor. We demonstrate that such an exciter can excite the rotor windings of this generator without forming a thermal-bridge across the cryostat wall. Finally, we provide estimates of the thermal load imposed by our prototype HTS-PM exciter on the rotor cryostat. We show that duty cycle operation of the device ensures that this heat load can be minimised, and that it is substantially lower than that of equivalently-rated conventional current leads.

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