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This paper discusses solid-state fault current limiting technologies. Both solid-state fault current limiters and converters can quickly limit DC fault currents and permit other protective devices to perform appropriate fault interruption and/or isolation. Different system protection strategies using solid-state fault current limiters and converters are presented and analyzed. The advantages and disadvantages...
Energy crisis in the modern world is one of the major hindrances in Smart Cities. Smart Cities have a lot of energy consuming elements so it is hard to build one using conventional energy sources because of the energy crisis. Reconstructing Smart Cities using unconventional energy sources like solar, piezoelectric etc. is highly complex, and demands innovative solutions. Today many people believe...
The purpose of this paper is to present a new solution to produce DC energy from electromagnetic radiation generated by compact fluorescent lamps and stored in the super capacitor bank. The proposed device is based on a magnetic coupling between flat wound induction coil and pollution generator represented in the compact florescent lamp. Most of the energy will be stored in the super capacitor and...
Due to the increasing energy demand there is a need of energy storage and advanced power conversion system. Energy which are available from the renewable energy sources can be efficiently store and can be convert to feed load as per the requirement. There are some power quality issues or poor voltage regulation where the load is supplied by renewable energy source. Therefore it is required to design...
This paper presents a new modulation for modular multilevel converters (MMC) based on a simple idea, which is very easy to implement. It consists of playing with the relative behaviour of each phase in order to obtain the desired AC voltage. This method also assures that the voltage capacitor in each sub-module remains constant. Moreover, this converter allows the operation of the system under unbalanced...
The purpose of the paper is to investigate the application of a Switched Reluctance Generator (SRG) for future wave energy converters. This machine presents some favourable features as compared to others. The machine optimal operation can be obtained after a detailed assessment of the control strategy. For this purpose, a SRG model is implemented in Matlab® Simulink® environment to find out the values...
A modified Marx-based solid-state topology for supplying inductive loads is presented. The basic principle of charging capacitors in parallel and discharging them in series is conserved. Due to the negative di/dt phase the inductive load imposes a reversible voltage power converter. Furthermore, in some applications such as eddy current septum magnets a negative current is required as well. The presented...
This paper proposes an energy and dc-bus voltage control strategy for the MMC converter, connected to HVDC link, using online quadratic optimization. The proposed approach leads to regulate simultaneously the energy sum and difference in “abc” frame and to maintain the DC voltage level around the operating point. The aim of this paper concerns the development of a reliable strategy based on optimization...
The modular multilevel converter (MMC) with cascaded full bridge cells is available for an AC/AC transmission system without transformers in high voltage line. When it is interconnected with power line, it is possible to control the active power flow in order to supply the power to the power line. This research applied the MMC to grid connection system of distributed generator for single phase AC/AC...
The Modular Multilevel Converter (MMC) topology has become one of the most promising solution in HVDC applications when compared with similar approaches. The evaluation of the power losses in an MMC terminal is fundamental to estimate the overall converter efficiency and size the required thermal management system. In this paper, a complete comparison of two methods to calculate conduction and switching...
This paper presents the control strategy of a dc series offshore wind farm with an onshore modular multilevel converter (MMC). The series connection of the dc wind turbines establishes the HVDC transmission voltage level with neither offshore transformer nor centralized converter station, indicating huge savings on offshore wind farm investment. However, power production unbalance in the wind farm...
In this article, a new grounded to floating admittance convertor employing only two voltage differencing transconductance amplifiers (VDTAs) has been suggested. The proposed configuration is able to convert any arbitrary grounded admittance into floating admittance without any requirement of additional passive element. The equivalent floating admittance value can tuned electronically through VDTA...
This paper presents the analysis and design ofa line interactive uninterruptible power supply (UPS) connected to a microgrid through a high step-up/down(bidirectional) dc-dc isolated modular multilevelconverter with a high input to output voltage ratio.Resonant switching is used on the MMC to improveoverall efficiency of the converter. The input source forthis converter is a set of series and parallel...
The modular multilevel converters are vulnerable to DC side faults, which are severe that can destruct the system if it is not designed to withstand these kinds of faults. This paper presents an analysis of the HVDC modular multilevel converter (MMC) based on full-bridge submodules during DC side fault conditions. A detailed theoretical analysis of the behavior of the full-bridge MMC during fault...
Conventionally, only one out of the two capacitors in a three-level submodule is involved in the arm current path to generate the first non-zero voltage level (E) in modular multilevel converters (MMCs). While two capacitors are connected in series to obtain the second non-zero voltage level (2E). In this paper and in order to generate the first non-zero voltage level (E); parallel-connection of the...
We present a control approach for the modular multilevel converter (MMC) with series and parallel module connectivity (MMSPC) that provides natural module balancing, reduced conduction losses, and enhanced robustness afforded by the parallel mode. In conventional MMC control, the voltage of each module's storage element has to be measured or estimated to enable the controller to equalize the voltages...
The average-value model (AVM) of the modular multilevel converters (MMCs) is the simplified one for the average response of switching devices, converters and control. The effect of sub-module capacitor voltage ripple on the MMC dynamic behavior is explored and an accurate average-value model of MMCs is established. Based on the proposed AVM, the equivalent impedances of the DC and AC sides in the...
This paper presents a steady-state analysis of the modular multilevel converter (MMC) for the second order voltage and current ripple prediction under unbalanced conditions, taking the impact of negative sequence current control into account. Using the circular relationship among current and voltage quantities, the magnitudes and initial phase angles of different circulating current components can...
The modular multilevel converter (MMC) has become one of the most promising converter technologies for medium/high-power applications, specifically for high-voltage direct current (HVDC) transmission systems. One of the technical challenges associated with the operation and control of the MMC-based system is to precharge the submodule (SM) capacitors to their nominal voltages during the startup process...
This paper presents a control strategy of modular multilevel converter which produces variable DC output from a three phase AC source. With this proposed strategy the output DC voltage of the converter can be bidirectional (i.e. both positive and negative) and can be varied to a value higher than the peak input voltage (boost), or to a value lower than the peak input voltage (buck). A simple synchronous...
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