High gain dc-dc converters are used in several applications which include solar photovoltaic system, switch-mode power supplies and fuel cells. In this paper, an ultra-high gain dc-dc boost converter is proposed and analyzed in detail. The converter has a gain of six times as compared with the boost converter. The high gain is achieved by utilizing switched inductors and switched capacitors. A modified voltage multiplier cell (VMC) with switched inductors is proposed. The converter has a single switch which makes its operation easy. Moreover, the voltage across the switch, diodes and capacitors are less than the output voltage which increases the overall efficiency of the converter. The converter performance in steady-state is analyzed in detail and it is compared with other latest high gain converters. The working of the converter in non-ideal conditions is also discussed in detail. The loss analysis is done using PLECS software by incorporating the real models of switches and diodes from the datasheet. To confirm and validate the working of the proposed converter a hardware prototype of 200 W is developed in the laboratory. The converter achieves high gain at low duty ratios and its performance is found to be good in open and closed loop conditions.

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A New Transformerless Ultra High Gain DC–DC Converter for DC Microgrid Application

The growth of renewable energy in the last two decades has led to the development of new power electronic converters. The DC microgrid can operate in standalone mode, or it can be grid-connected. A DC microgrid consists of various distributed generation (DG) units like solar PV arrays, fuel cells, ultracapacitors, and microturbines. The DC-DC converter plays an important role in boosting the output voltage in DC microgrids. DC-DC converters are needed to boost the output voltage so that a common voltage from different sources is available at the DC link. A conventional boost converter (CBC) suffers from the problem of limited voltage gain, and the stress across the switch is usually equal to the output voltage. The output from DG sources is low and requires high-gain boost converters to enhance the output voltage. In this paper, a new high-gain DC-DC converter with quadratic voltage gain and reduced voltage stress across switching devices was proposed. The proposed converter was an improvement over the CBC and quadratic boost converter (QBC). The converter utilized only two switched inductors, two capacitors, and two switches to achieve the gain. The converter was compared with other recently developed topologies in terms of stress, the number of passive components, and voltage stress across switching devices. The loss analysis also was done using the Piecewise Linear Electrical Circuit Simulation (PLCES). The experimental and theoretical analyses closely agreed with each other.

https://www.mdpi.com/1996-1073/14/9/2629/pdf

A New High-Gain DC-DC Converter with Continuous Input Current for DC Microgrid Applications

A non‐isolated quasi‐Z‐source‐based high‐gain DC–DC converter

This paper presents a bibliographical survey of the work carried out to date on the solid state transformer (SST). The paper provides a list of references that cover most work related to this device and a short discussion about several aspects. The sections of the paper are respectively dedicated to summarize configurations and control strategies for each SST stage, the work carried out for optimizing the design of high-frequency transformers that could adequately work in the isolation stage of a SST, the efficiency of this device, the various modelling approaches and simulation tools used to analyze the performance of a SST (working a component of a microgrid, a distribution system or just in a standalone scenario), and the potential applications that this device is offering as a component of a power grid, a smart house, or a traction system.

Solid state transformer technologies and applications: A bibliographical survey

Voltage lift is a well-known technique to improve the voltage gain of the converter. A combination of switched inductor and the conventional voltage lift technique can be used to achieve high gain, but the semiconductor’s stress is still high. An improved voltage lift technique by employing an extra diode and capacitor and a switched inductor is proposed, which signiﬁcantly increases the voltage boosting factor and reduces the voltage stress of semiconductor devices. The proposed converter is transformerless and non-isolated in nature. The proposed topology has a continuous input source current and has a common connection between the source and the load. The converter is controlled by a single switch, making it simple to use. The steady-state relations are drawn out in both continuous conduction mode (CCM) and discontinuous conduction mode (DCM). The effect of the unequal inductance on the voltage gain is carried out in detail. The improved voltage lift technique can develop the n- stage converter to improve voltage gain further and reduce stress on semiconductors. The proposed topology is compared with the recent converters, and the effect of the non-idealities on the voltage gain and losses occurring in the components is discussed in detail. A hardware prototype with a rating of 20V/300V, 250 W is built to test the suggested topology’s performance and theoretical analysis. At a 20-V input, the highest efﬁciency was measured to be 95.8%.

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1049/pel2.12279

Ultra high gain step up DC/DC converter based on switched inductor and improved voltage lift technique for high‐voltage applications

In this paper, a new hybrid transformerless high voltage gain DC-DC converter is created by merging two-inductor boost converter with voltage multiplier and switched capacitor cells. The main advantages of the proposed converter is the high voltage gain, simplicity of operation, high efficiency, reduced voltage and current stresses on the components. A 200 W, 37.4 V/400 V, 100 kHz prototype was implemented in laboratory to evaluate the proposed converter, which reached a maximum efficiency of 98.24 %.

Hybrid High Voltage Gain Transformerless DC-DC Converter

This article presents a family of transformerless active switched inductor and switched capacitor Cuk high voltage gain dc–dc converters. The configuration of this family has the advantages of nonpulsating output current, high step-up voltage gain, low voltage, and current stress across the component. Thus, conduction losses are decreased owing to the low-voltage-rating of the semiconductors. The Cuk converter with two switched-capacitor cells is evaluated in detail. The experimental results are provided to verify the theoretical analysis.

Family of Transformerless Active Switched Inductor and Switched Capacitor Ćuk DC–DC Converter for High Voltage Gain Applications

This paper presents a non‐isolated high step‐up buck–boost with a coupled inductor DC–DC converter relevant for distributed photovoltaic (PV) generation systems. The proposed topology can reach high voltage gain through the combination of a buck–boost converter with a coupled inductor. The configuration of the proposed converter allows to achieve a natural voltage clamp circuit for the switch, recovering the energy stored in the leakage inductance of the coupled inductor. Moreover, the converter allows soft‐switching conditions, that is, Zero Current Switching (ZCS) for the diodes and nearly ZCS for the active switch. Also, the proposed converter presents a low component count and common ground connection of the input and output. The proposed converter is evaluated theoretically by the principle of operation in continuous‐conduction mode (CCM) and discontinuous‐conduction mode (DCM), voltage gain derivation, external characteristics, semiconductor voltage stress, current stress, and design guidelines. Finally, a 650‐W, 36/380‐V, 50‐kHz prototype was built in the laboratory to experimentally evaluate the proposed converter, which reached a maximum efficiency rate of 96.58%.

High step‐up buck–boost DC–DC converter with coupled inductor and low component count for distributed PV generation systems

Voltage multiplier applied to boost DC–DC converter: Analysis, design, and performance evaluations

This paper presents a control architecture consisting of two communication networks to improve the communication modularity among power modules of a solid state transformer. The communication structure is based on a two full-duplex RS-485 network, one for high voltage side and other for the low voltage side, from which the central unit communicates and controls the local units using of a custom protocol. As central and local units, a Digital Signal Processor (DSP) is considered to perform the communication and control tasks. The communication buses are evaluated to find the main advantages, restrictions and limitations of this configuration.

Ademir Toebe

Papers

Hybrid High Voltage Gain Transformerless DC-DC Converter

Family of Transformerless Active Switched Inductor and Switched Capacitor Ćuk DC–DC Converter for High Voltage Gain Applications

High step‐up buck–boost DC–DC converter with coupled inductor and low component count for distributed PV generation systems

Voltage multiplier applied to boost DC–DC converter: Analysis, design, and performance evaluations

Double network control architecture for a modular solid state transformer