Ilya Galkin

Enhanced photovoltaic panel model for MATLAB-simulink environment considering solar cell junction capacitance

Maximal energy harvesting of photovoltaic panels is possible only if the load of photovoltaic cell is consuming current that corresponds to the maximal power point for condition combination on a certain moment. Correct and detailed mathematical modeling of photovoltaic panels is able to help to develop control techniques for maximum power point tracking converters. In order to overcome the disadvantages of Simscape solar cell block, a model of photovoltaic cell has been developed during the research on photovoltaic energy sources. Equations that are used for control of equivalent scheme of photovoltaic cell, comparison of the proposed model to the model represented in Matlab 2009 Simscape library and modeling description parameter estimation have been done. The comparison of models is represented in a steady state I-V curve characteristics that are compared to the experimental data obtained with a real photovoltaic panel. The proposed model showed results that are closer to the experimental data than the ones presented by Simscape library model. The performance of models in dynamic processes was not verified, but significant differences in behavior of the models have been ascertained.

Assessment of buck converter powered by current or voltage sources for LEDs luminary

This paper presents comparative investigation of both voltage and current fed buck converters. This comparison takes into account the controllability, efficiency and size of the converters. The first section of the paper briefly describes a standard voltage fed buck converter. Transformation of voltage fed buck converter into the current fed converter is presented next. Then the operation of current fed buck converter is discussed. On the next stage experimental estimation of current fed buck converter is described. Finally conclusions about current fed buck converter with LEDs are drawn.

Investigation of power supply methods for intelligent LED luminary

In the context of Intelligent Lighting System various lighting devices and technologies are compared. For the most technically beneficiary and rapidly developing LED luminaries control and power supply methods are analyzed and experimentally tested. The optimal one is chosen. Outlines of the further research are defined.

Optimizing of sampling in a low-cost single-phase instantaneous AC-grid synchronization unit with discrete calculation of derivative function

This paper deals with single-phase grid synchronization unit suitable for integration in interface converters of distributed renewable energy sources. A well known problem of the second orthogonal component for Park transformation of a phase-locked loop is successfully solved with a help of the approximate derivative function for the first time. Optimal sampling times for finding this derivative function are calculated with highest accuracy. It is shown that the implementation of approximate derivative function can reduce start-up time of the synchronization unit. The method is implemented in a low-cost microcontroller and successfully experimentally verified with a physical model of the grid, as well as with a real voltage sensor.

Validation of direct current control in LED lamp with non-inverting buck-boost converter

The given paper deals with equipment for smart lighting systems. A hypothesis, that current fed dimmable electrical ballasts with amplitude modulation of light could improve the controllability of such systems, is brought forward. Since there are very few natural current sources it is proposed to use a combination of a voltage source, switch mode voltage-to-current converter and current regulator. The first part can be built as a buck converter, while the regulator is similar to a boost converter. Together this gives a topology known as non-inverting buck-boost converter which, however, in the given case has to be controlled as two modules of “current source” nature. The control rules suitable for such strategy are discussed in the paper. In order to verify the idea a laboratory prototype of such converter has been built and tested. The features of the converter are given in the paper below. The obtained results show that the idea works in general, but certain instability and efficiency problems have to be solved. That is why it was concluded that a more accurate control method for the voltage-to-current source part has to be developed.

Comparative study of steady-state performance of voltage and current fed dimmable LED drivers

The paper focuses on electronic circuits for light regulation with arrays of light emitting diodes (LEDs) - dimmable LED drivers. Previously some well-known voltage fed (VF) topologies of such drivers (buck, boost and buck-boost) have been analyzed from the point of view of their non-linearity and accuracy achievable with practical control solutions in the static operation mode. It has been found that the volt-ampere curve of LEDs has a significant negative impact on the mentioned parameters in the case of VF drivers. The given paper extends this comparative study also to current fed (CF) dimmable drivers. The topologies of CF drivers are introduced, their static equations are obtained and then the CF drivers are tested experimentally. Conclusions about benefits of the CF drivers in the static operation mode compared with VF circuits are drawn in the final part of the paper.

New isolated interface converter for grid-connected PMSG based wind turbines

A new converter topology for a permanent magnet synchronous generator based variable speed wind turbine is presented in this paper. Main focus is on a combined topology of a controlled rectifier and a brand new step-up isolated DC/DC converter. This topology (controlled rectifier coupled with a quasi-Z-source based galvanically isolated step-up DC/DC converter) is essential to generate a regulated DC voltage (400 V DC typical for 230 V AC output) despite wide variations in the output voltage of a wind generator. The operation principles of the proposed topology are given and experimental results are analyzed.

Selection of power factor corrector for modular uninterruptable power supply system

The paper deals with power factor correction units suitable for implementation in uninterruptible power supplies. Several topologies of such correctors are described, analyzed and compared through simulation and experimentally. Special attention is paid to the efficiency of the correctors and to the possibility to build them utilizing unified power modules.

Design and implementation of flyback MPPT converter for PV-applications

One of major problems related with PV-applications is common mode currents. The issue can be solved in two ways: galvanic decoupling of AC-grid and chopping the common mode currents by additional actively controlled circuitry. Flyback converter is good solution for MPPT tracking for PV-modules up to 100-150 W with galvanic decoupling. The problem of designing of this type of converter is that most of design guides and literature is dedicated to consumer electronics applications. MPPT converter design have different starting points of calculations. The paper contains the suggested approaches to the calculations, design recommendations, considering the specific nature of PV-sources and NOCT model of PV-module. The approach calculations, design guidelines, recommendations and simulation of power electronics part of MPPT converter and experimental results with implemented circuit are presented and discussed. In order to increase the efficiency during tests the circuit was upgraded with active clamp. After the tests active clamp was upgraded to the forward active clamp topology. The efficiencies and key waveforms of voltages are compared and analyzed.

Analysis of electronic differential for electric kart

A simple electronic differential for electric kart with separately driven rear wheels is analysed. A kart model for electronic differential implementation has been developed. The performance of the elaborated differential has been tested using simulation in MatLab Simulink.