Solid-state switch-mode rectification converters have reached a matured level for improving power quality in terms of power-factor correction (PFC), reduced total harmonic distortion at input AC mains and precisely regulated DC output in buck, boost, buck-boost and multilevel modes with unidirectional and bidirectional power flow. This paper deals with a comprehensive review of improved power quality converters (IPQCs) configurations, control approaches, design features, selection of components, other related considerations, and their suitability and selection for specific applications. It is targeted to provide a wide spectrum on the status of IPQC technology to researchers, designers and application engineers working on switched-mode AC-DC converters. A classified list of more than 450 research publications on the state of art of IPQC is also given for a quick reference.

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A review of single-phase improved power quality AC-DC converters

This report presents a survey on generator concepts and power electronic concepts for wind turbines. The report is aimed as a tool for decision-makers and development people with respect to wind turbine manufactures, utilities, and independent system operators as well as manufactures of generators and power electronics. The survey is focused on the electric development of wind turbines and it yields an overview on: State of the art on generators and power electronics; future concepts and technologies within generators and power electronics; market needs in the shape of requirements to the grid connection, and; consistent system solutions, plus an evaluation of these seen in the prospect of market needs. This survey on of generator and power electronic concepts was carried out in co-operation between Aalborg University and Risoe National Laboratory in the scope of the research programme Electric Design and Control. (au)

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Conceptual survey of Generators and Power Electronics for Wind Turbines

Fast acting static synchronous compensator (STATCOM), a representative of FACTS family, is a promising technology being extensively used as the state-of-the-art dynamic shunt compensator for reactive power control in transmission and distribution system. Over the last couple of decades, researchers and engineers have made path-breaking research on this technology and by virtue of which, many STATCOM controllers based on the self-commutating solid-state voltage-source converter (VSC) have been developed and commercially put in operation to control system dynamics under stressed conditions. Because of its many attributes, STATCOM has emerged as a qualitatively superior controller relative to the line commutating static VAR compensator (SVC). This controller is called with different terminologies as STATic COMpensator advanced static VAR compensator, advanced static VAR generator or static VAR generator, STATic CONdenser, synchronous solid-state VAR compensator, VSC-based SVC or self-commutated SVC or static synchronous compensator (SSC or S2C). The development of STATCOM controller employing various solid-state converter topologies, magnetics configurations, control algorithms, switching techniques and so on, has been well reported in literature with its versatile applications in power system. A review on the state-of-the-art STATCOM technology and further research potential are presented classifying more than 300 research publications.

Static synchronous compensators (STATCOM): a review

A pulse-width-modulated (PWM) high-frequency link series-parallel resonant converter operating with fixed frequency is proposed. A simple analysis and design procedure are presented. The proposed configuration has a number of desirable features, such as high efficiency for very wide load variations with a narrow range of duty-cycle ratio control, and load short-circuit capability. Detailed experimental results obtained from a 48 V output, 500 W experimental converter are presented to verify the concept. >

Fixed-frequency PWM series-parallel resonant converter

A novel nonlinear optimal controller for a static compensator (STATCOM) connected to a power system, using artificial neural networks, is presented in this paper. The action dependent heuristic dynamic programming, a member of the adaptive critic designs family is used for the design of the STATCOM neurocontroller. This neurocontroller provides optimal control based on reinforcement learning and approximate dynamic programming. Using a proportional-integrator approach, the proposed neurocontroller is capable of dealing with actual rather than deviation signals. Simulation results are provided to show that the proposed controller outperforms a conventional PI controller for a STATCOM in a small and large multimachine power system during large-scale faults, as well as small disturbances

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A Proportional-Integrator Type Adaptive Critic Design-Based Neurocontroller for a Static Compensator in a Multimachine Power System

This paper presents a nonlinear controller for GTO based static compensators (STATCOM). This controller permits achievement of high transient performances for this kind of compensator. The design of the control system is based upon the differential algebra theory. Such a control system enables global stabilization of the compensation system and thus helps to improve largely the transient performance of the global system. The system is simulated using the averaged model for inverters in order to validate the controller performance.

Nonlinear control for STATCOM based on differential algebra

This paper describes a new low-cost three-phase AC-DC high-power/low-harmonic-controlled rectifier and its analysis, design, and performance. The circuit consists of a three-phase diode-bridge rectifier, followed by a boost stage containing only one switch and one boost inductor. The proposed converter is used to automatically draw sinusoidal input-current waveforms with high efficiency. This is achieved with discontinuous-input voltage to the rectifier and with a discontinuous-inductor-current mode of operation of the boost converter. By using a simplified single-phase model and symbolic analysis method, analytical equations are obtained and used for design.

Analysis and design of single-controlled switch three-phase rectifier with unity power factor and sinusoidal input current

The properties of a dual thyristor are advantageously used for the development of very high-efficiency dc-dc converters. A new device named ``dual thyristor'' having static and dynamic characteristics dual to that of a thyristor has been recently reported. The development aspects of a dual thyristor based high-efficiency dc-dc converter with an intermediate ac link using a high-frequency inverter is described. The output voltage is regulated by varying the frequency of operation of the inverter. In spite of the relatively high-frequency operating range of this device between 30 kHz and 100 kHz, high efficiency of operation of the converter is obtained due to the use of lossless snubbers. Further, the selfprotective nature of the device against overcurrents enables a high reliability of operation of the dc-dc converter.

DC to DC Converters with High-Frequency AC Link

Electrical drives are very complex systems which makes difficult their study when detailed analysis is required along with their global behaviour. With the help of advanced software tools for circuit analysis and the modelling of a drive system following a modular approach, it becomes much easier to study those complex systems. This paper presents a methodology for use with the Matlab/Simulink environment in which the main parts of an electrical drive are modelled as interlinked functional blocks. The complete drive system (from supply to mechanical load) is analysed as a set of independent but integrated modules.

An integrated solution for simulating electrical drive systems with Matlab/Simulink

A study of static and dynamic characteristics of a series-resonant power converter incorporating dual thyristor switches is presented. In a series-resonant converter (SRC), the dual thyristor operates at a frequency above its resonant frequency and this operation is efficiently achieved because of negligible turn-on and turn-off losses even at high frequencies. After reviewing the characteristics of a dual thyristor, the authors plot normalized static characteristics that are useful in designing SRC incorporating dual thyristors. For small signal perturbations, Bode diagrams of the control to output voltage transfer function are obtained by calculation and compared with experimental measurements. The effects of large signal perturbation on the stability of the SRC are also presented.

V. Rajagopalan

Papers

Nonlinear control for STATCOM based on differential algebra

Analysis and design of single-controlled switch three-phase rectifier with unity power factor and sinusoidal input current

DC to DC Converters with High-Frequency AC Link

An integrated solution for simulating electrical drive systems with Matlab/Simulink

Static and small signal analysis of a series-resonant converter operating above its resonant frequency