Patent•
Multilevel cascade voltage source inverter with seperate DC sources
14 Sep 1995-
TL;DR: In this paper, a multilevel cascade voltage source inverter with separate DC sources is described, which is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation, power line conditioning, series compensation, phase shifting and voltage balancing.
Abstract: A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.
Citations
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TL;DR: The most important topologies like diode-clamped inverter (neutral-point clamped), capacitor-Clamped (flying capacitor), and cascaded multicell with separate DC sources are presented and the circuit topology options are presented.
Abstract: Multilevel inverter technology has emerged recently as a very important alternative in the area of high-power medium-voltage energy control. This paper presents the most important topologies like diode-clamped inverter (neutral-point clamped), capacitor-clamped (flying capacitor), and cascaded multicell with separate DC sources. Emerging topologies like asymmetric hybrid cells and soft-switched multilevel inverters are also discussed. This paper also presents the most relevant control and modulation methods developed for this family of converters: multilevel sinusoidal pulsewidth modulation, multilevel selective harmonic elimination, and space-vector modulation. Special attention is dedicated to the latest and more relevant applications of these converters such as laminators, conveyor belts, and unified power-flow controllers. The need of an active front end at the input side for those inverters supplying regenerative loads is also discussed, and the circuit topology options are also presented. Finally, the peripherally developing areas such as high-voltage high-power devices and optical sensors and other opportunities for future development are addressed.
6,472 citations
TL;DR: An inverter configuration based on three-level building blocks to generate five-level voltage waveforms is suggested and it is shown that such an inverter may be operated at a very low switching frequency to achieve minimum on-state and dynamic device losses for highly efficient MV drive applications while maintaining low harmonic distortion.
Abstract: This paper gives an overview of medium-voltage (MV) multilevel converters with a focus on achieving minimum harmonic distortion and high efficiency at low switching frequency operation. Increasing the power rating by minimizing switching frequency while still maintaining reasonable power quality is an important requirement and a persistent challenge for the industry. Existing solutions are discussed and analyzed based on their topologies, limitations, and control techniques. As a preferred option for future research and application, an inverter configuration based on three-level building blocks to generate five-level voltage waveforms is suggested. This paper shows that such an inverter may be operated at a very low switching frequency to achieve minimum on-state and dynamic device losses for highly efficient MV drive applications while maintaining low harmonic distortion.
1,150 citations
TL;DR: The Fast Acting Static Synchronous Compensator (STATCOM) as discussed by the authors is a representative of FACTS family and is extensively used as the state-of-theart dynamic shunt compensator for reactive power control in transmission and distribution system.
Abstract: 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.
368 citations
Patent•
18 Aug 2011
TL;DR: In this paper, an integrated circuit chip includes a first input port, a first output port, and first and second transistors electrically coupled in series across the first inputport, and the second transistor is also adapted to provide a path for current flowing through the first outputport when the first transistor is in its non-conductive state.
Abstract: An integrated circuit chip includes a first input port, a first output port, and first and second transistors electrically coupled in series across the first input port. The second transistor is also electrically coupled across the first output port and is adapted to provide a path for current flowing through the first output port when the first transistor is in its non-conductive state. The integrated circuit chip additionally includes first driver circuitry for driving gates of the first and second transistors to cause the transistors to switch between their conductive and non-conductive states. The integrated circuit chip further includes first controller circuitry for controlling the first driver circuitry such that the first and second transistors switch between their conductive and non-conductive states to at least substantially maximize an amount of electric power extracted from an electric power source electrically coupled to the first input port.
262 citations
10 Dec 2002
TL;DR: In this article, the authors focus on the latest development of inverters for photovoltaic AC-modules and propose a plug-and-play concept for the AC-module, which can provide a modular design and a flexible behavior in various grid conditions.
Abstract: This review-paper focuses on the latest development of inverters for photovoltaic AC-modules. The power range for these inverters is usually within 90 Watt to 500 Watt, which covers the most commercial photovoltaic-modules. Self-commutated inverters have replaced the grid-commutated ones. The same is true for the bulky low-frequency transformers versus the high-frequency transformers, which are used to adapt the voltage level. The AC-module provides a modular design and a flexible behaviour in various grid conditions. It hereby opens the market for photovoltaic-power for everyone at a low cost due to the plug and play concept, which also makes a further enlargement of the system possible.
251 citations
References
More filters
TL;DR: In this article, an active power filter with quadruple voltage-source PWM converters was developed, of which the power circuit consists of quadruple-VRS converters.
Abstract: The control strategy of active power filters using switching devices is proposed on the basis of the instantaneous reactive power theory. This aims at excellent compensation characteristics in transient states as well as steady states. The active power filter is developed, of which the power circuit consists of quadruple voltage-source PWM converters. As the result, interesting compensation characteristics were verified experimentally which could not be obtained by the active power filter based on the conventional reactive power theory.
722 citations
TL;DR: The Static Condenser (STATCON) as discussed by the authors is a static condenser that is similar to the rotating synchronous condenser (SVC) and has similar output characteristics to those of the SVC.
Abstract: The availability of high power gate-turn-off (GTO) thyristors has led to the development of controllable reactive power sources, using electronic switching power converters, for use in power transmission systems This new technology has resulted in equipment that is fundamentally different from the conventional thyristor-controlled static VAr compensator (SVC) The new equipment is called a static condenser (STATCON) because its steady state output characteristics are similar to those of the rotating synchronous condenser The paper describes the fundamental operating principles, functional characteristics and basic control approach of the STATCON, with particular reference to a /spl plusmn/100 MVAr prototype planned to be installed at the Tennessee Valley Authority (TVA) Sullivan substation, USA This installation will be the first demonstration of a STATCON under the EPRI flexible AC transmission systems (FACTS) program, and will be the largest installation of its type in the world >
380 citations
Patent•
14 Jan 1974TL;DR: In this paper, the authors propose a programmed switching system for converting direct current into alternating current or some other variable current, which employs a number of stages connected in cascade, each stage includes an electrical source or an electrical energy storage unit and switch means adapted to bypass the energy source or storage unit, to interconnect the source or a storage unit with other electrical energy sources or storage units across a load, and to reverse the direction of current flow in the load to apply, for example, a quasi-sinusoidal voltage across the load.
Abstract: A programmed switching system for converting direct current into alternating current or some other variable current, or for converting alternating current of one frequency into alternating current of another frequency. The system employs a number of stages connected in cascade. Each stage includes an electrical energy source or an electrical energy storage unit and switch means adapted to bypass the energy source or storage unit, to interconnect the source or storage unit with other electrical energy source or storage units across a load in a programmed fashion, and to reverse the direction of current flow in the load to apply, for example, a quasi-sinusoidal voltage across the load.
372 citations
TL;DR: In this paper, a static VAr generator (SVG) using self-commutated inverters of 80 MVA capacity was developed and successfully applied to an annual 154 KV power system to stabilize the power system.
Abstract: A static VAr generator (SVG) using self-commutated inverters of 80 MVA capacity was developed and successfully applied to an annual 154 KV power system to stabilize the power system. The SVG consists of 48 pulse multiple inverters whereby gate turn-off (GTO) thyristors are applied. After installing it at a power system site, a field test was conducted to confirm the system stabilizing effect. The test results displayed the expected performance, and the SVG was proven to be effective power system stabilizer. The outline of the 80 MVA SVG, technical features, and the test results are described. >
309 citations
TL;DR: In recent years, there has been a rapid increase in the number of thyristor-controlled shunt compensators used in industrial and utility systems for dynamic power factor correction and terminal voltage stabilization as mentioned in this paper.
Abstract: In recent years, there has been a rapid increase in the number of thyristor-controlled shunt compensators used in industrial and utility systems for dynamic power factor correction and terminal voltage stabilization. These thyristor-controlled shunt compensators function as variable reactances operated in both the inductive and capacitive domains.
293 citations