Multilevel inverters: a survey of topologies, controls, and applications
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.
Citations
More filters
TL;DR: In this paper, the most relevant characteristics of multilevel converters, to motivate possible solutions, and to show that energy companies have to bet on these converters as a good solution compared with classic two-level converters.
Abstract: This work is devoted to review and analyze the most relevant characteristics of multilevel converters, to motivate possible solutions, and to show that we are in a decisive instant in which energy companies have to bet on these converters as a good solution compared with classic two-level converters. This article presents a brief overview of the actual applications of multilevel converters and provides an introduction of the modeling techniques and the most common modulation strategies. It also addresses the operational and technological issues.
1,847 citations
TL;DR: The basic operation and the most used modulation and control techniques developed to date of neutral-point-clamped inverters are presented and some technological problems such as capacitor balance and losses are presented.
Abstract: Neutral-point-clamped (NPC) inverters are the most widely used topology of multilevel inverters in high-power applications (several megawatts). This paper presents in a very simple way the basic operation and the most used modulation and control techniques developed to date. Special attention is paid to the loss distribution in semiconductors, and an active NPC inverter is presented to overcome this problem. This paper discusses the main fields of application and presents some technological problems such as capacitor balance and losses.
1,556 citations
Cites background from "Multilevel inverters: a survey of t..."
...Another commutation introduced in [2] as type 2 takes place between one outer and one inner device....
[...]
...Highly popular are the voltage-source multilevel inverters, which can be divided into three categories, according to their topology: neutral point clamped (NPC), flying capacitor (FLC), and cascade H-bridge [1], [2]....
[...]
TL;DR: In this article, two types of pulsewidth-modulated modular multilevel converters (PWM-MMCs) with focus on their circuit configurations and voltage balancing control are investigated.
Abstract: A modular multilevel converter (MMC) is one of the next-generation multilevel converters intended for high- or medium-voltage power conversion without transformers. The MMC is based on cascade connection of multiple bidirectional chopper-cells per leg, thus requiring voltage-balancing control of the multiple floating DC capacitors. However, no paper has made an explicit discussion on voltage-balancing control with theoretical and experimental verifications. This paper deals with two types of pulsewidth-modulated modular multilevel converters (PWM- MMCs) with focus on their circuit configurations and voltage-balancing control. Combination of averaging and balancing controls enables the PWM-MMCs to achieve voltage balancing without any external circuit. The viability of the PWM-MMCs, as well as the effectiveness of the voltage-balancing control, is confirmed by simulation and experiment.
1,506 citations
Cites background from "Multilevel inverters: a survey of t..."
...Two of the representatives are: 1) the diode-clamped multilevel converter (DCMC) [6], [7]; 2) the flying-capacitor multilevel converter (FCMC) [8]....
[...]
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
Cites background or methods from "Multilevel inverters: a survey of t..."
...It is possible that the solution makes it possible for active damping of system oscillations or transients in addition to the regenerative capability....
[...]
...As the switching losses of MV semiconductor devices make up a major portion of the device losses, their reduction allows the maximum output power to be increased....
[...]
...A simple way to establish a series connection of power devices without derating is with the 3L inverter topology [2], [21], [22]....
[...]
...Recently, the use of ML configurations has become more prevalent in the active rectifier field [19], [29], [121]....
[...]
20 Oct 2009
TL;DR: This paper serves as an introduction to the subject for the not-familiarized reader, as well as an update or reference for academics and practicing engineers working in the field of industrial and power electronics.
Abstract: Multilevel converters are considered today as the state-of-the-art power-conversion systems for high-power and power-quality demanding applications. This paper presents a tutorial on this technology, covering the operating principle and the different power circuit topologies, modulation methods, technical issues and industry applications. Special attention is given to established technology already found in industry with more in-depth and self-contained information, while recent advances and state-of-the-art contributions are addressed with useful references. This paper serves as an introduction to the subject for the not-familiarized reader, as well as an update or reference for academics and practicing engineers working in the field of industrial and power electronics.
949 citations
References
More filters
01 Jan 1980
TL;DR: In this article, a neutral-point-clamped PWM inverter composed of main switching devices which operate as switches for PWM and auxiliary switching devices to clamp the output terminal potential to the neutral point potential has been developed.
Abstract: A new neutral-point-clamped pulsewidth modulation (PWM) inverter composed of main switching devices which operate as switches for PWM and auxiliary switching devices to clamp the output terminal potential to the neutral point potential has been developed. This inverter output contains less harmonic content as compared with that of a conventional type. Two inverters are compared analytically and experimentally. In addition, a new PWM technique suitable for an ac drive system is applied to this inverter. The neutral-point-clamped PWM inverter adopting the new PWM technique shows an excellent drive system efficiency, including motor efficiency, and is appropriate for a wide-range variable-speed drive system.
4,432 citations
TL;DR: The neutral-point-clamped PWM inverter adopting the new PWM technique shows an excellent drive system efficiency, including motor efficiency, and is appropriate for a wide-range variable-speed drive system.
Abstract: A new neutral-point-clamped pulsewidth modulation (PWM) inverter composed of main switching devices which operate as switches for PWM and auxiliary switching devices to clamp the output terminal potential to the neutral point potential has been developed. This inverter output contains less harmonic content as compared with that of a conventional type. Two inverters are compared analytically and experimentally. In addition, a new PWM technique suitable for an ac drive system is applied to this inverter. The neutral-point-clamped PWM inverter adopting the new PWM technique shows an excellent drive system efficiency, including motor efficiency, and is appropriate for a wide-range variable-speed drive system.
4,328 citations
"Multilevel inverters: a survey of t..." refers background in this paper
...Three different topologies have been proposed for multilevel inverters: diode-clamped (neutral-clamped) [4]; capac-...
[...]
08 Oct 1995
TL;DR: This paper presents three multilevel voltage source converters: (1) diode-clamp, (2) flying-capacitors, and (3) cascaded-inverters with separate DC sources.
Abstract: Multilevel voltage source converters are emerging as a new breed of power converter options for high-power applications. The multilevel voltage source converters typically synthesize the staircase voltage wave from several levels of DC capacitor voltages. One of the major limitations of the multilevel converters is the voltage unbalance between different levels. The techniques to balance the voltage between different levels normally involve voltage clamping or capacitor charge control. There are several ways of implementing voltage balance in multilevel converters. Without considering the traditional magnetic coupled converters, this paper presents three recently developed multilevel voltage source converters: (1) diode-clamp, (2) flying-capacitors, and (3) cascaded-inverters with separate DC sources. The operating principle, features, constraints, and potential applications of these converters are discussed.
3,232 citations
"Multilevel inverters: a survey of t..." refers background or methods in this paper
...Three different topologies have been proposed for multilevel inverters: diode-clamped (neutral-clamped) [4]; capacitor-clamped (flying capacitors) [1], [5], [6]; and cascaded multicell with separate dc sources [ 1 ], [7]‐[9]....
[...]
...Three different topologies have been proposed for multilevel inverters: diode-clamped (neutral-clamped) [4]; capacitor-clamped (flying capacitors) [ 1 ], [5], [6]; and cascaded multicell with separate dc sources [1], [7]‐[9]....
[...]
...The circuit has been called the flying capacitor inverter [ 1 ], [5], [6] with independent capacitors clamping the device voltage to one capacitor voltage level....
[...]
...For these reasons, a new family of multilevel inverters has emerged as the solution for working with higher voltage levels [ 1 ]‐[3]....
[...]
TL;DR: Direct self-control (DSC) as discussed by the authors is a simple method of signal processing that gives converter-fed three-phase machines an excellent dynamic performance, and it is sufficient to process the measured signals of the stator currents and the total flux linkages only.
Abstract: The new direct self-control (DSC) is a simple method of signal processing that gives converter-fed three-phase machines an excellent dynamic performance. To control the torque of, say, an induction motor, it is sufficient to process the measured signals of the stator currents and the total flux linkages only. In the basic version of DSC, the power semiconductors of a three-phase voltage source inverter are directly switched on and off via three Schmitt triggers, comparing the time integrals of line-to-line voltages to a reference value of desired flux, if the torque has not yet reached an upper-limit value of a two-limit torque control. Optimal performance of drive systems is accomplished in steady state as well as under transient conditions by combination of several two-limit controls. >
1,730 citations
TL;DR: Simulation and experimental results show the superiority of the back-to-back diode-clamped converter over two-level pulsewidth-modulation-based drives.
Abstract: This paper presents transformerless multilevel power converters as an application for high-power and/or high-voltage electric motor drives. Multilevel converters: (1) can generate near-sinusoidal voltages with only fundamental frequency switching; (2) have almost no electromagnetic interference or common-mode voltage; and (3) are suitable for large voltampere-rated motor drives and high voltages. The cascade inverter is a natural fit for large automotive all-electric drives because it uses several levels of DC voltage sources, which would be available from batteries or fuel cells. The back-to-back diode-clamped converter is ideal where a source of AC voltage is available, such as in a hybrid electric vehicle. Simulation and experimental results show the superiority of these two converters over two-level pulsewidth-modulation-based drives.
1,398 citations