Implementation Possibilities of SMD Capacitors for High Power Applications

Focus is on implementation possibilities of surfacemount device (SMD) to be used in high power applications. SMD capacitors reduce the size and dimensions of a power circuit and increase the flexibility of placement of other components. Ceramic and electrolytic capacitors are compared by means of voltage ripple, volume, labour-intensity and impedance. A 1 kW experimental setup of a quasi-Z-Source inverter (qZSI) based converter was built to compare SMD capacitor performance in the quasi-Z-source (qZS) network

Evaluation of Control Solution for Grid Inverter of Low Power Wind Turbine for Implementation with Inexpensive Hardware

The growing energy demand all over the world and the approaching deficit of traditional energy resources makes the development of renewable energy sources including wind energy necessary. A significant part of any wind turbine is the grid interface converter, operation of which depends a lot on the control system. Although this consideration is valid for all wind turbines, it is especially important for small wing turbines where control system cannot be expensive. This paper evaluates the possibility to split control functions into more simple ones with a goal of their practical implementation in a low cost system. The proposed version of split control is explored using MATLAB-Simulink simulation. It is concluded that the proposed control principle is capable of operation, but further experimental testing is necessary to validate it completely

Study of Simple MPPT Converter Topologies for Grid Integration of Photovoltaic Systems

This paper presents a study of two simple MPPT converter topologies for grid integration of photovoltaic (PV) systems. A general description and a steady state analysis of the discussed converters are presented. Main operating modes of the converters are explained. Calculations of main circuit element parameters are provided. Experimental setups of the MPPT converters with the power of 800 W were developed and verified by means of main operation waveforms. Also, experimental and theoretical boost properties of the studied topologies are compared. Finally, the integration possibilities of the presented MPPT converters with a grid side inverter are discussed and verified by simulations

Investigation of Supercapacitor Bidirectional Power Flow System

It is possible to realize supercapacitor charging and discharging devices through BUCK-BOOST converter. In this paper alternative system of charging and discharging using supply side VS inverter for charging and supercapacitor side inverter for discharging of supercapacitor is investigate. In such device using H-bridge topology of Pulse Width regulated inverter a storage capacitors can be distributed in system as at input as also output and that allow to provide more efficient storage. Using in supercapacitor side a VS inverter allow to obtain reverse discharging of capacitor operating supply side inverter in quasi-BOOST regime. In the paper operational regimes of such device are described as also main expressions for calculation of processes are obtained. It’s shown that most efficient operation and control case should be at boundary current shape of the primary winding of transformer. At some proper operational parameters it’s possible to obtain maximum of transmitted power; for that also a voltage level of the secondary side supercapacitor have to be installed on proper level dependent on transformation ratio of transformer

Experimental Verification of Light Electric Vehicle Charger Multiport Topology

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 the multiport topology is not preferred due to high losses at phase shifts that exceed 40 deg. The topology is well suited for battery charging, as the required charging voltage change will be less than 30%. To evaluate the multiport topology in the proposed application, a low power 250 W prototype charging station was designed, built and tested

Operation of Resonant DC/DC Converter in the BUCK Operation Regime

The series resonant DC/DC converter with isolation transformer is investigated. When switching frequency of input inverter bridge is above the resonant one a shortening of the naturally half-waves of current through a L-C resonant circuit takes place resulting in a circulating current through the DC supply source reducing a mean value of supply current and also reducing load voltage in respect to the one at normally resonant case. The main relations for the case with strong voltage supply source are obtained and operation regimes at raised switching frequency investigated using a computer modeling. Some conclusions are made for proper calculation of parameters. It is shown that the shape of the resonant circuit current at raised frequency grows to the triangular one and that asks for proper correction of the expressions obtained for sinusoidal case. Applying qZ input link processes quite differ from observed for the strong supply – arise charging of the capacitors of the link by influence of circulating current and this phenomena impedes to reducing of the load voltage. That qZ link does not allow to create proper regulation of load parameters

Feasibility Study of Inductor Coupling in Three-Level Neutral-Point-Clamped Quasi-Z-Source DC/AC Converter

This paper presents a comparative feasibility study of coupled inductor implementation in a three-level neutral-point-clamped quasi-Z-source (3L-NPC qZS) DC/AC converter. Our theoretical verification shows that coupling of the qZS inductors enables reductions in the size and weight of the magnetic components or in the input current ripple. Our mathematical analysis shows the difference of inductor currents at variable circuit parameters. Simulations results are provided to verify our theoretical assumptions