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.
Chaotic nature of renewable energy sources connected with nonlinear loads may cause serious problems to the utility grid, e.g. voltage and frequency disturbances, harmonic pollution. Due to that, many European governments have set strict regulations to the grid energy injection. As a result, the power quality has become one of the major obstacles for nearly zero energy buildings to be connected with...
Startup is known as the most critical phase of any power electronic converter. Uncharged capacitors and resonance circuits cause high current spikes during startup that reduce the lifespan of semiconductors or in the worst case, immediate break down. Although the startup of power electronic converters is a very practical and necessary topic, only few papers cover different startup algorithms. No papers...
Startup of any converter is a very dynamic and hardly controllable process. The regulator outputs are fluctuating, sensor readings are constantly changing and the fault probability is the highest. That is especially true for grid connected converters that need to be exactly in phase with the grid before an actual connection is done. In this paper a startup strategy for a grid connected PV micro inverter...
This paper describes the grid-connected isolated microconverter based on qZS network. Due to many benefits quasi-Z-source based converters are suitable for renewable energy application, in particular for the photovoltaic systems. However, there are some problems that need closer analysis before quasi-Z-source converter can be fully implemented in PV microinverters. The goal of this work is to address...
This paper presents a three-phase three-level neutral-point-clamped quasi-Z-source inverter as a novel solution for photovoltaic applications. The topology was derived by combining properties of the quasi-Z-source networks with those of three-level neutral-point-clamped inverters. A case study system, a steady state analysis and a novel special modulation technique for shoot-through states distribution...
This paper presents a three-level neutral point clamped voltage source inverter with hysteresis voltage control. Output characteristics of the converter and voltage control for a voltage source inverter are described. A simulation model of a three-level neutral point clamped inverter with a control system based on the hysteresis voltage control was developed. Basic diagrams that demonstrate performance...
This paper describes a multiport topology based charging station for light electric vehicles, like electric-motor assisted bicycles (pedelec). The multiport topology allows energy flow control between the charging ports, alternative energy ports and the grid port. Every port can act bidirectionally, enabling easy integration of additional energy storages. Power flow regulation in a wide range with...
Ten different modulation methods of the isolated quasi Z-source inverter based DC-DC converter were tested to find out radiated emission levels. EMC measurements were performed on a low power 250 W prototype. A radiated emission test was carried out in a GTEM cell (gigahertz transverse electromagnetic cell) according to the EMC standard IEC 61000-4-20. To obtain a complete overview of the emissions,...
This paper presents a novel class of quasi-Z-source galvanically isolated DC-DC converters intended for the integration of low voltage renewable energy sources into a DC microgrid. These converters combine characteristics of the transformer based and the inductor based impedance-source galvanically isolated DC-DC converters. They feature the continuous input current essential for photovoltaic applications...
A study of a novel control method for a battery cell equaliser, based on the shunting transistor method is presented. The method allows cell balancing in both battery operating modes, recharging and driving modes. To verify the applicability of the method, computer simulation was conducted analysing how the system balances during a driving period, by following a real current profile measured from...
This paper describes a new multiport fast charger for an electric vehicle based on the concept of the active power electronic transformer. Energy sources, chargeable batteries and storages are connected together via a common multi-winding transformer and simple full-bridge inverters. The theoretical control principles and the proposed topology are verified by computer simulations.
Residential generation of electricity from renewable sources has grown substantially owing to active governmental stimulation programs in many countries. Permanent magnet synchronous generators (PMSG) are a preferable solution for residential wind turbines (WTs) due to their high efficiency and reliability. In the design of grid integration equipment, PMSG-based WTs need special attention because...
Along this paper, it will be presented how the Electric Vehicle (EV) bidirectional chargers can help the Distribution Grid. In addition to the battery charge and the Vehicle-to-Grid functions (V2G), the reactive power can be compensated according to an established reactive power reference. A three-phase bidirectional inverter connected with a DC link to a DC/DC bidirectional converter is utilized...
This paper addresses an approach to improve the efficiency of the quasi-Z-source (qZS) converters. By replacing the qZS diode by the n-channel MOSFET, the power loss over a diode can be reduced in a qZS network. The paper presents operation basics of the approach, analysis and comparison of the power losses of the traditional and proposed designs and experimental validation of the theoretical assumptions.
Smart grid structure could be very complex. Active power electronic transformers, composing an important part of the smart grid, could have many roles in that stochastic and variable system. The modular structure (consisting of many base modules) is the key to obtain the needed flexibility. The goal of this research was to develop a base module of the active power electronic transformer to be used...
This paper describes a novel power conditioning system for residential fuel cell power plants, consisting of a step-up DC/DC converter and a single or a multiphase inverter. To increase the efficiency of the whole system a quasi Z-source inverter along with a step-up isolation transformer and a voltage doubler rectifier can be used. Due the continuous input current and low current ripple, the service...
This paper presents a new power conditioning system for the fuel cell powered distributed generation systems. The main emphasizes is done on the brand new step-up isolated DC/DC converter topology proposed by the authors. The proposed topology (quasi-Z-source inverter based step-up DC/DC converter with high-frequency isolation) is essential to generate a regulated higher DC voltage (600 VDC typical...
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.