A New Soft-Switched High Step-Up Trans-Inverse DC/DC Converter Based on Built-In Transformer

This article proposes a new Zero-Voltage Switching (ZVS) high step-up DC/DC converter based on a built-in transformer for renewable energy applications. The proposed topology utilizes a Three-Winding Built-In Transformer (TWBT) to increase the voltage gain, but unlike most coupled-inductor-based DC-DC converters, high output voltages can be obtained under a lower magnetic turns ratio. In this circuit, with the help of a regenerative active clamp circuit, the energy of the leakage inductor from the TWBT is absorbed and transferred to the output, therefore, the ZVS conditions at turn-on time are achieved for switches. The voltage stresses across the switches of the proposed topology are limited, and the diodes reverse-recovery issue are eliminated. Due to the low input current ripple, the suggested topology can be used for renewable energy sources. Furthermore, because of the low number of components along with the soft-switching operation, the proposed circuit can offer enough high efficiency. The operational principle, steady-state analysis, and characteristics of the proposed converter are provided. Finally, a 200 W prototype with 25 V input and 400 V output voltage is built to validate the analytical results

High Gain Magnetically Coupled Single Switch Quadratic Modified SEPIC DC-DC Converter

This article proposes, analyzes, and tests an improved high voltage gain dc-dc converter based on a single-ended primary-inductor converter (SEPIC). The proposed magnetically coupled quadratic modified SEPIC converter (MCQ-MSC) employs a coupled transformer with an optimized design to obtain a high voltage boost factor by controlling the transformer's turn ratio along with the switching duty cycle. Thanks to the unique structure of the coupled transformer, high voltage gain is obtained at low turns ratio, which is highly desirable for high voltage applications and the compact size of the converter. In addition to the coupled transformer, a voltage-boosting module is utilized to achieve a very high output voltage for a low switching duty cycle. The proposed inverter has a single switch with a wide control range of duty cycle (0<D<1), causing low conducting losses and high efficiency. Furthermore, a clamping circuit is successfully designed to remove the leakage inductance effects of the coupled transformer on the power switch. The proposed MCQ-MSC drains a continuous current from the input dc source, which makes it a suitable choice for renewable energy sources (RES). The hardware prototype of the proposed converter is tested to verify the mathematical expressions and theoretical results.acceptedVersionPeer reviewe

New high step-up coupled dual winding quadratic enhanced SEPIC DC-DC converter

This paper introduces a non-isolated high step-up dc-dc converter originated from single-ended primary-inductor converter (SEPIC). The suggested dual winding quadratic enhanced SEPIC converter (DWQ-ESC) employs a voltage-boosting module to attain superior boost ability. A unique coupled inductor is exploited to regulate the boost factor by tuning the transformer's turns ratio along with the switching duty cycle. Additionally, very high boost factor is achieved at low transformer's turns ratio (limited around 1.0). As a result, low winding turns ratio is required for very high gain applications. Also, a clamping circuit is considered to eliminate the leakage inductance effects of the coupled inductor across the power switch. A single switch with a full control range of duty cycle ($0 < \mathrm{D} < 1$) is utilized in the proposed DWQ-ESC that results in low conducting losses and high efficiency. The introduced DWQ-ESC drains a smooth current from the input dc source that makes it appropriate for renewable energy sources (RES) such as photovoltaic (PV) and wind sources. Theoretical analysis and simulation results are presented in the paper to demonstrate that the introduced topology can obtain high boost factor with a reduced duty ratio in comparison with existing similar quadratic dc-dc converters.acceptedVersionPeer reviewe

A new soft‐switching high gain DC/DC converter with bipolar outputs

Abstract This paper introduces a new single‐input multi‐output step‐up DC/DC converter with soft‐switching performance and low input current for renewable energy applications. The proposed topology uses a three‐winding coupled‐inductor (TWCI) and voltage multiplier circuits to achieve high voltage gains. The bipolar output voltages of the proposed converter can be varied independently by tuning the turns ratios of the TWCI. Due to the semi‐trans‐inverse specification of the suggested topology, high voltage gains can be obtained under a lower number of turns ratio in the magnetic device. Furthermore, a regenerative passive clamp technique mitigates the voltage stress on the single power switch. Additionally, the power dissipations are further reduced by considering a resonant tank in the circuit. In the converter, the parasitic leakage inductances of the TWCI windings help to provide the soft‐switching conditions for the switch and also to eliminate the reverse‐recovery loss for all converter diodes. The operating mode of the presented converter has been introduced and the steady state, along with the main operating equations have also been derived. Finally, the theoretical analysis is verified by a sample prototype 235 W at the input voltage 25 V and outputs of 200 V and −200 V