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.
In this paper, a fully ZVT auxiliary cell for boost type resonant converters is proposed to achieve soft switching in ON-OFF control mode. In conventional ON-OFF methods, transient and switching losses at the beginning and end of each power pulse decrease the overall efficiency of the system at high modulation frequencies. This ZVT cell offers zero voltage switching without imposing extra resonant...
This paper proposes a fixed frequency based sliding mode (SM) controller for transformer-less single phase inverter for photovoltaic (PV) application with active power decoupling minimizing the capacitance requirement. Unlike conventional power decoupling techniques in full bridge converters, the proposed technique incorporates a large sinusoidal swing of the half-bridge capacitor voltages and a limited...
This paper deals with the AC and DC dynamic voltage control in a hybrid DC/AC Microgrid (MG) with central and distributed Battery Energy Storage Systems (BESSs), applying a power sharing mechanism between the different devices in the MG. The MG is composed by a multiport transformation center and two fixed frequency 3 phase AC Nanogrids (NGs) coupled to a DC bus through 3-phase Power Electronic Converters...
Isolated AC/DC matrix converter can realize AC-DC conversion with high frequency transformer to isolate the AC and DC side. Thanks to its high-power density and high efficiency, it is an attractive alternative to the conventional voltage source converter in hybrid microgird as interlinking converter, which adopts power frequency transformers when isolation is required. To realize this, bi-directional...
This paper investigates the fault ride-through (FRT) capability of a hybrid AC/DC microgrid during both AC and DC network faults. In this investigation, commonly proposed FRT strategies for the distributed energy resources and AC and DC microgrids are implemented while the interlinking bidirectional converter is operated in power transfer mode. The investigations have shown that improvement in the...
Droop control is a widely used technique for load sharing in DC microgrids (MGs). However, it has its limitations due to the MG voltage deviating from its rated level and, more importantly, it suffers from possible poor current sharing accuracy. Voltage drops across coupling line impedances is the main factor that causes these limitations, which is further deteriorated by the virtual impedance introduced...
This paper proposes a DC link controller based on H∞ method for robust and reliable operation of a single-phase grid-connected inverter with an LCL-filter in photovoltaic (PV) applications. The H∞ DC link controller minimizes the bus voltage fluctuations caused by the power variations of PV system. Also, the controller ensures system robustness against such power variations, which conventional controllers...
The appearance of harmonics in the grid voltage is an issue for the generation systems and grid connected consumers. This paper presents the basic control strategy to be implemented in Synchronous Power Control (SPC) based power converters, which contributes to reduce the harmonic content in the voltage by means of injecting different harmonic current to the grid using a separated virtual admittance...
The increasing use of grid-connected inverters to connect renewable energy sources to a power grid will have globally important effect on grid performance. A mismatch between the grid and inverter impedance may cause harmonic resonances, which can lead to instability of the grid and disruption of inverter operation. The grid dynamics vary over time, so the inverter should adapt to the varying conditions...
Capacitor-current-feedback active damping method is commonly used in LCL-filtered grid-connected inverters, which attenuates the resonance peak by emulating a virtual resistor in parallel with the filter capacitor. Taking the digital control delay into account, the emulation component becomes frequency-dependent, and it will turn negative when the filter resonance frequency becomes higher than one-sixth...
This paper proposes a modular multilevel converter (MMC) topology, designed particularly for load balancing in 50 Hz railway applications. The asymmetrical character of the traction load requires higher device rating for a Double-star or Delta-connected MMC compared to a symmetrical static compensator. This is due to the symmetrizing components to rebalance the capacitor voltages in the submodules...
The high number of cells employed in a Modular Multilevel Converter represents a challenge for the control hardware. Some authors have proposed the use of digital communications to simplify the assemblage and maintenance in such converters, but the latency they add has undesirable consequences for the closed-loop performance. In this paper, we propose a model-based compensation of the latency that...
Nowadays, the Modular Multilevel Converter (MMC) based HVDC has been considered as a promising technology to meet the increasing electric power demand. However, constructing new transmission lines becomes more and more difficult because of environmental issues. Consequently, the newly constructed DC lines have to share the right of way with existing AC transmission in close proximity. Meanwhile, as...
Overcurrent or overvoltage problems caused by DC line faults endanger the security of modular multilevel converter based high voltage direct current (MMC-HVDC) system. To improve the reliability of fault identification for MMC-HVDC transmission lines, a novel pilot protection scheme based on DC power difference is proposed in this paper. Characteristics of the DC power difference between positive...
Planar coils with litz wires are used a lot in inductive power transfer for electric vehicles. When the litz wire is properly selected for the coil, the winding resistance is composed of DC resistance and proximity-effect resistance. The calculation of DC resistance is simple, using the cross-sectional area and the length of the wire, but the calculation of proximity-effect resistance is complicated,...
Inductive power transfer (IPT) is widely discussed as an alternative to contact charger for plug-in hybrid and electric vehicles (PHEV/EV). This paper analyzes a contactless battery charger back end power factor correction (PFC) concept, which allows to reduce the primary side circuit complexity and physical size. For that purpose, the main volume and loss factors of a contactless battery charger...
The stray magnetic field around inductive-power-transfer coils is influenced by the phases of the transmitter's and receiver's currents. This influence is analyzed with the diagrams of phasors for the currents and magnetic fields. The dual-side-controlled converter is applied for the circuit realization, in which the bridges with MOSFETs are used for the inverter on the transmitter side and rectifier...
This paper proposes a power factor correction method of a non-resonant IPT system using a four-winding transformer. The proposed technique is applied to the IPT system with a dual active bridge converter to reduce conduction loss and winding loss. When two pairs of the primary-side and the secondary-side wires are connected in parallel, the low coupling coefficient between the wires driven by in-phase...
In this paper we propose the mode selection strategy of a multi-mode single-stage single-phase inverter and the associated mode selection scheme for double-line-frequency power pulsation decoupling between the input an the output port for PV (photovoltaic) panel applications. Multiple modulation strategies are used along the line cycle to optimize the overall efficiency of the converter. The proposed...
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.