Contactless Excitation System for Synchronous Generators (original) (raw)
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Study of a synchronous excitation generator with rotating rectifier
The development of today's synchronous machines is tightly connected with use of brushless excitation systems. They have advantages like high exploitation reliability, long-term operation, low power for control and they don't need any special maintenance during exploitation. Leading hydro generators and other synchronous machines manufacturers like ALSTOM, GENERAL ELECTRIC, ABB, ELECTROSILA and others use such excitation generators in a wide range of power which reaches 1000 MW for turbogenerators. In our country these excitation generators are manufactured for relatively low synchronous generator's power of the order of a few hundreds kW. Attempting to use them at higher powers, leads to some problems such as overheating the exciter's inductor steel. The analyzing of these problems, particularly the excitation generator's magnetic field study, as well as their elimination is the subject of the present project. Study method Analytical model of an exciter with rot...
Design of a Contact-less Energy Transfer System for Electrically Excited Synchronous Machines
International Symposium on Power Electronics, Electrical Drives, Automation and Motion (SPEEDAM), 2020
In this paper, the design of a resonant LLC converter based contact-less energy transfer system (CET) is presented. The system uses a rotary transformer and thus it can be implemented as a substitute for slip ring and brush assemblies that are primarily used for the transfer of DC power into the rotor of an electrically excited synchronous machine. The resonant LLC converter is utilized in order to improve the power density and output voltage regulation of the CET system. Furthermore, simulation and measurement results of the system are presented in the paper.
Modelling the brushless excitation system for a synchronous machine
IET Electric Power Applications, 2009
The structure and the operation of the model for the brushless excitation system for a synchronous machine are presented. The nonlinear model including the excitation machine, the AC-AC converter supplying the excitation machine and the rectifier diode bridge, mounted on the rotor, is based on a state machine. The states are defined by current commutation in the power electric devices. The operation of the excitation system model is verified by measurements with a slip-ring machine imitating the excitation machine. The excitation system model is integrated and simulated as a part of a synchronous machine simulator.
2009
Summary . In this paper a hybrid excitation system for a br ushless synchronous generator working with variable speed in an autonomous energy generation system (e.g. airplane power grid) is presented. A conception of a dual-stator hybrid exciter is proposed. Comparison study of classical and hybrid exciter has been carried out. For the electromagnetic calculation two approaches have been applied: analytical approach (based on the circuit model and sizing equations) a nd numerical approach (using field simulator FLUX2D). Provisional design calculations have been performed using the analytical approach. Next, to verify the calculatio n results and to optimise the magnetic and electric circuit of the machine, the field simu lator FLUX2D has been used.
Analysis, Modeling, and Design Considerations for the Excitation Systems of Synchronous Generators
IEEE Transactions on Industrial Electronics, 2017
The traditional generating set is usually comprised of a classical, wound-field, salient-pole or cylindrical rotor synchronous generator, excited by a separate smaller machine, via a rotating, uncontrolled diode rectifier. The effects of the commutation processes of the diode bridge are often overlooked and neglected. However due to the uncontrolled nature of this process, the rectified voltage available at the main generator's rotor terminals can be significantly lower than the expected value. This is especially true for low-to-medium power rated systems. In this paper, a detailed investigation of these aspects is done and an accurate voltage drop prediction model is then proposed. The model is validated with finite element analysis and with experimental results for a particular low-medium rated generating system in the 400kVA power range. The validated tool is then integrated into an innovative design tool, which first performs an analytical pre-sizing procedure and then utilizes a genetic algorithm approach to identify an optimal excitation system design, aimed at minimizing the voltage drop ensuing from the diode commutations, with minimum impact on the overall efficiency.
Analysis of Static Excitation System Models for Synchronous Machine
2020
Excitation systems can be defined as the system that provides field current to the rotor winding of a generator. Welldesigned excitation systems provide reliability of operation, stability and fast transient response. Excitation systems provide and control the amount of DC current provided by field windings of the generator and this contains all the power controlling and protection components. To fulfill the power demands and desired output characteristics, the excitation system should be configured to match the power system to which the generator is attached. There are two primary aspects of the excitation mechanism: It generates DC voltage (and power) to allow the current through the generator's field windings and it offers a way of controlling the generator's terminal voltage to suit a specified setting point and to provide damping for oscillations in the power system. An aim of the paper is to analyze the two modern static excitation system Viz. ST1A and ST7B from the po...
A static exciter with interleaved buck converter for synchronous generators
International Journal of Hydrogen Energy, 2017
In this study, an interleaved buck converter based static excitation system is proposed for large-scale synchronous generators where thyristor controlled systems are widely used. The proposed system removes the slow response drawback of the thyristor controlled systems even for dynamic load conditions. The finite element analysis based model of the synchronous generator's electromagnetic system is obtained and co-simulations of the modeled generator and proposed interleaved buck converter are performed. Results obtained from simulation results show that, the proposed system offers better performance in terms of step response and inductor current ripple. The simulation results are validated with experimental studies. All measurement, monitoring and control processes have been performed with field programmable gate array called NI CompactRIO platform and Lab-VIEW software.
Control and Configuration of Generator Excitation System as Current Mainstream
An Integral part of generator is Excitation System and new technology of Excitation System has been developed utilizing a power sources. The most important a portion of electric power system is synchronous generator due to it is the source of electrical energy and energy transformation is possible only when generator excitation exists. The generator excitation systems work when generator excitation system operates a dc charge to the generator heads to energize the field of magnetic around them to enable the electricity that should be generated. There are brushless and brush-type exciters and generators are built in exciters or charge can be established from any external source. This paper presents the control and configuration of synchronous generator excitation system as current mainstream technology, which is widely designed for feeding of turbo generator excitation winding with auto-regulated DC in generator operation, control normal and emergency modes. In this paper discuss appended on excitation system models of synchronous generator and emphasis on drawbacks, different possibilities to regulate generator excitation, de-excitation systems and overvoltage Protection with special newly developed nonlinear system regulation. And also append short descriptions of functions, compositions, Structure and Working Principle of Generator Excitation System.
International Journal of Innovation and Applied Studies, 2013
An Integral part of generator is Excitation System and new technology of Excitation System has been developed utilizing a power sources. The most important a portion of electric power system is synchronous generator due to it is the source of electrical energy and energy transformation is possible only when generator excitation exists. The generator excitation systems work when generator excitation system operates a dc charge to the generator heads to energize the field of magnetic around them to enable the electricity that should be generated. There are brushless and brush-type exciters and generators are built in exciters or charge can be established from any external source. This paper presents the control and configuration of synchronous generator excitation system as current mainstream technology, which is widely designed for feeding of turbo generator excitation winding with auto-regulated DC in generator operation, control normal and emergency modes. In this paper discuss appended on excitation system models of synchronous generator and emphasis on drawbacks, different possibilities to regulate generator excitation, de-excitation systems and overvoltage Protection with special newly developed nonlinear system regulation. And also append short descriptions of functions, compositions, Structure and Working Principle of Generator Excitation System.
Non-Salient Brushless Synchronous Generator Main Exciter Design for More Electric Aircraft
Energies
This paper presents a prototype of high speed brushless synchronous generators (BSG) design for the application in autonomous electric power generation systems (e.g., airplane power grid). Commonly used salient pole field of the main generator part of BSG was replaced with a prototype non-salient pole field. The main objective of the research is an investigation into the advantages and disadvantages of a cylindrical field of the main generator part of BSG over the original salient pole field. The design process of the prototype generator is presented with a focus on the electromagnetic and mechanical finite element method (FEM) analysis. The measurements of prototype and commercial BSG were conducted for the nominal speed of 8 krpm. The advantages and disadvantages of the proposed solution were established based on measurements in load and no-load conditions.