The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
When the poloidal field (PF) magnet power supplies (MPSs) of 11 units are operated, maximum power of 200 MVA is required to achieve long pulse operation of Korea superconducting tokamak advanced research (KSTAR). Motor generator (MG) system was installed to resolve the power shortage because the available grid power is only 100 MVA at the National Fusion Research Institute site. MG system is composed...
A novel control strategy is proposed for a bidirectional multiport single phase two stage microinverter without electrolytic capacitor. The application of this converter is for power factor correction under non-linear grid tied load. The converter is composed of a triple active bridge series-resonant DC/DC converter cascaded with a voltage source inverter where a film capacitor is used in the DC-Link...
The open-ended winding configuration allows feeding an electric motor from two sides. If one of them is connected to an inverter closed on a floating capacitor, operating as an active power filter, it is possible to obtain several benefits over the traditional configuration, such as an extended field weakening speed range and a lower current ripple. However, the additional converter causes switching...
Microgrid research and development in the past decades have been one of the most popular topics. Similarly, the photovoltaic generation has been surging among renewable generation in the past few years, thanks to the availability, affordability, technology maturity of the PV panels and the PV inverter in the general market. Unfortunately, quite often, the PV installations are connected to weak grids...
The objective of this research is to analyze and evaluate the performance of the proposed shunt-series switched multi-functional grid-connected inverter (SSS-MFGCI) for mitigating unbalanced voltage sag and swell problem in distributed generation system or microgrid. Three quantitative performance evaluation factors, namely fault level factor, rating factor, and grid stiffness factor, are proposed...
This paper discusses the harmonics compensation of the constant dc-capacitor voltage-control (CDCVC)-based strategy of smart charger (SC) for electric vehicles (EVs) in single-phase three-wire distribution feeders (SPTWDFs) under the distorted source voltage and load currents conditions. The basic principle of the CDCVC-based harmonics compensation strategy under the distorted source voltage and load...
In this paper, a wireless modular control strategy for input-series output-parallel (ISOP) inverter system is proposed to ensure equal sharing of input voltage and output current among the constituent inverters. Compared with existing control strategies for the ISOP inverter system, such as centralized control which restricts the modularity of the system and distributed control which realizes voltage...
This paper presents a novel control method that enables operation of Modular Multilevel Converters under non-sinusoidal AC supply conditions based on frequency domain decomposition of supply voltages. The proposed control method enables to inject or draw near sinusoidal grid currents even during the presence of harmonic distortions in the supply voltages without the use of additional hardware filters...
Unbalanced operation between panel-level modular inverters constrains the operating range of grid-tied cascaded H-bridge Photovoltaic (PV) inverter system when the active and reactive power of the architecture changes. The main objective of this paper is to propose a distributed control approach for balancing reactive power among inverters. The distributed controller allows fully decentralized architecture...
This paper puts forth a vision for scalable distribution grid integration of energy resources such as rooftop photovoltaics (PVs) and electric vehicles (EVs). The output of these resources vary temporally in an unpredicted manner. Therefore, they bring substantial challenges to utilities vis-a-vis massive deployment of such resources. By leveraging the fact that most of the distributed energy resources...
The droop control technology, which can achieve an autonomous power sharing among distributed resources interface converters, provides the advantages of enhanced system reliability and reduced complexity. However, the reactive power sharing accuracy of the conventional Q — V droop method can be degraded due to its dependence on the line impedances. The Q — V droop control method was proposed to reduce...
The well-known droop control and master-slave control methods are two dominant coordinative control schemes for inverter interfacing parallel distributed energy resources (DERs) in islanded AC microgrids. However, both these two control methods have some drawbacks and inherent limitations in practical application. After analyzing their complementary strengths and weaknesses, this paper proposed a...
The stability problems of power electronics interfaced distributed generators with low inertia and damping can be well solved by the virtual synchronous generator technologies. However, when the grid voltages become unbalanced, oscillations in both the real and reactive power will arise with unbalanced voltages and currents of VSG being noticed. This paper proposed a flexible power control method...
In this work an ac-dc-ac multilevel power converter is investigated. The developed configuration is composed of one single-phase ac-dc-ac three-leg module and two H-bridges, one of them connected in the shared part of the system to employ multilevel voltages to input and output converter, and the other one connected on the grid side for input overvoltage. The converter is employed in applications...
This paper proposes a single-phase ac-dc-ac converter composed of two three-leg converters connected in series with an H-bridge on its grid side. The proposed converter allows to feed the load voltage with sinusoidal voltages with constant amplitude and frequency and to operate with sinusoidal grid current with high power factor. Besides, the converter can be used to mitigate fundamental overvoltage...
Advanced control techniques such as Volt-Watt and Volt-VAR Control have been developed for high integration of distributed renewable energy, such as Photovoltaic (PV) resources, on an electric distribution system. However, designing these control parameters which yields the best results in the system is complicated and depends on feeder conditions. This paper proposes a method to properly design the...
An improved hybrid unified power flow controller (IHUPFC) is developed in this paper to increase the utilization rate of transmission line and enhance the transmission capacity in extra-high voltage (EHV) and ultra-high voltage (UHV) grid. Based on introducing the existing power flow controllers, the advantages of IHUPFC in structure and performance are analyzed. The proposed IHUPFC is composed of...
The popularly used current controlled architecture for grid connected converter systems needs a phase locked loop (PLL) for its operation. The PLL generates the unit vectors required for desired current reference generation. This paper proposes to eliminate the grid voltage sensor and presents a method to estimate the unit vectors and grid frequency without a dedicated grid voltage sensor. The estimation...
Direct power control (DPC) is an attractive control method for three-phase pulse-width modulation (PWM) rectifiers, due to the merits of simple structure, quick dynamic response and little tuning work. However, conventional switching table based DPC presents relatively high power ripples and current harmonics, which is especially serious when the grid voltages are unbalanced. Introducing space vector...
Nowadays, due to the high-scale penetration of photovoltaic systems, reliable and efficient photovoltaic grid-connected systems using the advances of power electronics and advanced control techniques are desirable. In this paper, using the general structure for synchronous dq0 frame, a single-stage three-phase grid-connected photovoltaic inverter with a nonlinear control strategy is developed to generate...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.