Andrei Blinov

Full soft-switching high step-up DC-DC converter for photovoltaic applications

In this paper a full soft-switching high step-up DC-DC converter is introduced as an alternative approach to module integrated converters for photovoltaic applications. The presented operation principle and key equations can be used as design guidelines for component and parameter estimation in practical applications. The proposed DC-DC converter was verified by help of simulations and experiments. Power loss analysis based on the semiconductor datasheet values showed that the converter tends to achieve an efficiency of 92.8% at the maximum power point.

Feasibility study of Si and SiC MOSFETs in high-gain DC/DC converter for renewable energy applications

This paper presents an evaluative comparison of Si- and SiC-based MOSFETs, operating in a qZS-derived step-up DC/DC converter. Special attention is paid to switching behaviour and power dissipation. A range of experiments was performed to determine an optimal di/dt value during transients to minimise overvoltages and dynamic losses. Additionally, some particular properties such as gate driver requirements, housing types and price are discussed.

Full soft-switching bidirectional current-fed DC-DC converter

The focus is on a switching control strategy for the galvanically isolated bidirectional current-fed dc-dc converter. The converter under study employs the current-fed full-bridge stage at the low-voltage side and the voltage-fed half-bridge stage at the high-voltage side. The current-fed side of the converter utilizes four-quadrant switches comprised of two MOSFETs each. The switching sequence proposed enables soft-switching operation of all switches in both directions of energy transfer for a wide range of dc voltage gain and load variations. Moreover, it features natural clamping and thus eliminates voltage overshoot at the turn-off of switches at the current-fed side. Full zero-current switching is achieved in the current-fed side, while full zero-voltage switching is accommodated in the voltage-fed side. Theoretical predictions were verified with simulations in PSIM 9.

Four Novel PWM Shoot-Through Control Methods for Impedance Source DC-DC Converters

This study proposes four novel pulse width modulation (PWM) shoot-through control methods for impedance source (IS) galvanically isolated DC-DC converters. These methods are derived from a PWM control method with shifted shoot-through introduced by the authors in 2012. In contrast to the baseline solution, where the shoot-through states are generated by the simultaneous conduction of all transistors in the inverter bridge, our new approach is based on the shoot-through generation by one inverter leg. The idea is to increase the number of soft-switched transients and, therefore, decrease the dynamic losses of the front-end inverter. All the proposed approaches are experimentally verified through an insulated-gate bipolar transistor-based IS DC-DC converter. Conclusions are drawn in accordance with the results of the switching loss analysis.

Experimental verification of DC/DC converter with full-bridge active rectifier

The half-bridge converter with a phase-shifted active rectifier bypasses the traditional hard-switched half-bridge converter with a diode rectifier regarding to high switching losses and parasitic oscillations in the inverter. The presented galvanically isolated step-down DC/DC converter with an improved control algorithm for the full-bridge active rectifier features reduced energy circulation and switching losses. The performance can be improved under wide input voltage and load variations. The advantages of the converter were verified with a 1 kW converter prototype and the test results were in full agreement with the expected waveforms. The presented steady-state operation principle and mathematical analysis of the converter based on the simulation and experimental results can be used as design guidelines for component and parameter estimation in practical applications.

Three-level half-bridge ZVS DC/DC converter for electrolyzer integration with renewable energy systems

This paper presents findings of a R&D project targeted to the development of a galvanically isolated step-down DC/DC converter for electrolyzer integration with renewable energy systems. The topology proposed is a three-level neutral point clamped half-bridge with a high-frequency isolation transformer and a current doubler rectifier that fulfils all the targets set by the designers. Despite an increased component count the proposed converter is very simple in design and operation. The paper outlines the design with several recommendations and guidelines, and also discusses the experimental results obtained.

Evaluation of GaN HEMTs for high-voltage stage of isolated DC-DC converters

This paper presents an experimental study of the half-bridge based on high voltage enhancement mode GaN high electron mobility transistors (HEMTs). It was tested with pure inductive load at various switching frequencies and power levels to verify gate driver and cooling system. All tests performed confirm excellent performance of the 650 V GaN HEMTs and the developed half-bridge stage may be applied in future design of the fully controlled DC-DC converter for PV applications.

A novel high-voltage half-bridge converter with phase-shifted active rectifier

The half-bridge converter with phase-shifted active rectifier allows us to avoid drawbacks of the traditional hard-switched half-bridge converter with a diode rectifier, such as high semiconductor losses and parasitic oscillations in the inverter. This paper introduces a novel improved control algorithm for a full-bridge phase-shifted active rectifier, allowing reduction of the energy circulation during its operation. The advantages of the algorithm are verified with a small-scale converter prototype. The experimental results were found in full accordance with expected waveforms.

New DC/DC Converter for Electrolyser Interfacing with Stand-Alone Renewable Energy System

Abstract This paper presents findings of a R&D project targeted to the development of a galvanically isolated step-down DC/DC converter for electrolyzer integration with renewable energy systems. The presented converter with an improved control algorithm for the full-bridge active rectifier features reduced energy circulation and switching losses. The performance can be improved under wide input voltage and load variations. The advantages of the converter were verified with a 1 kW converter prototype and the test results were in full agreement with the expected waveforms. The presented steadystate operation principle and mathematical analysis of the converter based on the simulation and experimental results can be used as design guidelines for component and parameter estimation in practical applications.

Cooling Methods for High-Power Electronic Systems

Cooling Methods for High-Power Electronic Systems Thermal management is a crucial step in the design of power electronic applications, especially railroad traction and automotive systems. Mass/size parameters, robustness and reliability of the power electronic system greatly depend on the cooling system type and performance. This paper presents an approximate parameter estimation of the thermal management system required as well as different commercially available cooling solutions. Advantages and drawbacks of different designs ranging from simple passive heatsinks to complex evaporative systems are discussed.