A High Step-up Transformer-Less DC-DC Converter with Continuous Input Current
01 Feb 2020-
TL;DR: In this paper, a non-isolated step-up DC-DC converter by a coupled inductor is introduced and also analyzed, which provides high voltage gain with low turn ratio, which reduces the core size, volume and weight of the converter and also reduces the cost of the system.
Abstract: Recently, renewable and sustainable energy sources such as PV are utilized as clean energy sources however, these energy sources have a low output voltage, and in high voltage applications high gain DC-DC converters are applied to enhance the output voltage of these types of energy sources. In this article, a non-isolated step-up DC-DC converter by a coupled inductor is introduced and also analyzed. Unlike previous DC-DC converters, this converter provides high voltage gain with low turn ratio, which reduces the core size, volume and weight of the converter and also reduces the cost of the system. Also, by coupled inductor turn's ratio reduction, the voltage stress of the semiconductor elements is reduced subsequently. A passive clamp circuit is also applied in the proposed converter, which boosts the converter voltage gain and also, reduces the voltage across of the switches. To demonstrate the benefits of the presented topology, a laboratory model is fabricated with 20V input and 200V output voltages and power rate of 200W in 25 kHz operation frequency.
Citations
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TL;DR: In this paper, the authors proposed a new nonisolated full soft-switching step-up dc/dc converter based on single-ended primary inductor converter (SEPIC) structure.
Abstract: This article introduces a new nonisolated full soft-switching step-up dc/dc converter based on single-ended primary inductor converter (SEPIC) structure. The proposed topology utilizes a three-winding coupled-inductor (TWCI) to increase the voltage gain, but unlike other coupled-inductor-based converters, its voltage gain is increased by reducing its magnetic turns ratio. Moreover, the secondary and tertiary turns ratios of the TWCI can be used as an additional design freedom to extend the voltage gain, which indicates more converter flexibility. Due to the continuous input current, the proposed converter can be used for many types of renewable energy sources. Also, the leakage energy from the TWCI has further been recycled and transferred to the output with the help of a regenerative passive clamp circuit. Due to the soft-switching performance, the proposed converter has no switching losses at the turn- on instant for the power switch and reverse recycling losses of the diodes. Furthermore, the use of a small number of components along with the soft-switching performance offer high efficiency. Steady-state analysis and design considerations are discussed thoroughly. Finally, a 200-W prototype with 200 V output voltage is provided to verify the theoretical analysis.
20 citations
5 citations
TL;DR: In this paper , the authors proposed a multi-port bidirectional DC-DC converter for electric vehicle (EV) usages, which has the ability for step-up and step-down operating.
Abstract: This article proposes a new multi-port bidirectional DC-DC converter for electric vehicle (EV) usages. The recommended converter has the ability for step-up and step-down operating. The bidirectional power flow makes the proposed converter suitable for EV applications, where a storage unit is charged and discharged. The proposed converter has three ports (VHigh, VLow, and V2), and all of these ports have bidirectional features. In each operation mode (step-up or step-down), the output port is loaded by two independent input sources. Also, a high voltage conversion ratio is achieved with low power switches duty cycle and reduced peak voltage over semiconductors. Input current with reduced ripple, low components count, a simple circuit with low cost and volume, and high efficiency are the main advantages of the presented bidirectional topology. In order to demonstrate the performance and effectiveness of the recommended converter, operational and steady-state analysis in step-up and step-down modes, design consideration, efficiency calculation, and comparison with other DC-DC converters are provided Finally, a prototype with a step-up power of 120 W and a step-down power of 30 W is created, and experimental data are shown to validate the numerical investigations.
TL;DR: In this article , a two-winding coupled inductor has been employed to enhance the output voltage level in a high step-up DC-DC converter, which offers several advantages, including a simple structure, high voltage gain, high efficiency, reduced voltage stress on the semiconductors, and fewer components.
Abstract: This article presents a novel structure for a high step-up DC-DC converter. The proposed converter offers several advantages, including a simple structure, high voltage gain, high efficiency, reduced voltage stress on the semiconductors, and fewer components. A two-winding coupled inductor has been employed to enhance the output voltage level in this topology. The suggested structure has only one power switch with low ON-state resistance (RDS-ON), reducing power losses. Moreover, the zero-voltage switching (ZVS) and zero-current switching (ZCS) features of the diodes of the proposed converter result have improved overall efficiency. To evaluate and ascertain the enhanced performance of this configuration, the study of different modes of operation, steady-state investigation, and a comparative study between the proposed and other relevant topologies are presented. A laboratory prototype is designed and implemented with an input voltage of 12 V, an output voltage of 150 V, and a 200 W rated power level under a 50 kHz switching frequency. The maximum efficiency of the recommended topology is measured at the rated output power, equal to 96.98%. Also, for an output power range from 50 W to 350 W, the efficiency is obtained higher than 95%.
References
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TL;DR: In this paper, the authors comprehensively review and classify various step-up dc-dc converters based on their characteristics and voltage-boosting techniques, and discuss the advantages and disadvantages of these voltage boosting techniques and associated converters.
Abstract: DC–DC converters with voltage boost capability are widely used in a large number of power conversion applications, from fraction-of-volt to tens of thousands of volts at power levels from milliwatts to megawatts. The literature has reported on various voltage-boosting techniques, in which fundamental energy storing elements (inductors and capacitors) and/or transformers in conjunction with switch(es) and diode(s) are utilized in the circuit. These techniques include switched capacitor (charge pump), voltage multiplier, switched inductor/voltage lift, magnetic coupling, and multistage/-level, and each has its own merits and demerits depending on application, in terms of cost, complexity, power density, reliability, and efficiency. To meet the growing demand for such applications, new power converter topologies that use the above voltage-boosting techniques, as well as some active and passive components, are continuously being proposed. The permutations and combinations of the various voltage-boosting techniques with additional components in a circuit allow for numerous new topologies and configurations, which are often confusing and difficult to follow. Therefore, to present a clear picture on the general law and framework of the development of next-generation step-up dc–dc converters, this paper aims to comprehensively review and classify various step-up dc–dc converters based on their characteristics and voltage-boosting techniques. In addition, the advantages and disadvantages of these voltage-boosting techniques and associated converters are discussed in detail. Finally, broad applications of dc–dc converters are presented and summarized with comparative study of different voltage-boosting techniques.
1,230 citations
"A High Step-up Transformer-Less DC-..." refers background in this paper
...Therefore, the nonisolated step-up DC-DC converters should have capability of increasing voltage and reducing total power losses [16]....
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TL;DR: A novel high step-up dc-dc converter for distributed generation systems is proposed, to utilize two capacitors and one coupled inductor to achieve a highstep-up voltage gain and the voltage stress on the main switch is reduced.
Abstract: In this paper, a novel high step-up dc-dc converter for distributed generation systems is proposed. The concept is to utilize two capacitors and one coupled inductor. The two capacitors are charged in parallel during the switch-off period and are discharged in series during the switch-on period by the energy stored in the coupled inductor to achieve a high step-up voltage gain. In addition, the leakage-inductor energy of the coupled inductor is recycled with a passive clamp circuit. Thus, the voltage stress on the main switch is reduced. The switch with low resistance RDS(ON) can be adopted to reduce the conduction loss. In addition, the reverse-recovery problem of the diodes is alleviated, and thus, the efficiency can be further improved. The operating principle and steady-state analyses are discussed in detail. Finally, a prototype circuit with 24-V input voltage, 400-V output voltage, and 200-W output power is implemented in the laboratory to verify the performance of the proposed converter.
258 citations
"A High Step-up Transformer-Less DC-..." refers background in this paper
...But in practice, due to the presence of the parasitic elements such as the resistance of the input coil winding and the ON-state resistance of the switch at high operating cycles, the voltage drops, and their conduction losses greatly increase [12-13]....
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TL;DR: In this article, the authors proposed a dc-dc converter configuration, which successfully integrates two technologies, including a switched capacitor and a switched coupled inductor, into one converter, and achieved a voltage gain of up to 11.2%.
Abstract: This paper presents a novel dc–dc converter configuration, which successfully integrates two technologies, including a switched capacitor and a switched coupled inductor, into one converter. By adopting a coupled inductor to charge a switched capacitor, the voltage gain can be effectively increased, and the turns ratio of the coupled inductor can be also reduced. Not only lower conduction losses but also higher power conversion efficiency is benefited from a lower part count and lower turns ratios. The proposed converter is simply composed of six components, which can be further derived to varied converters for different purposes, such as a bidirectional converter. The operating principle and steady-state analysis are discussed in this paper. A 250-W laboratory hardware prototype is completed and verified. The voltage gain is up to 11. The highest efficiency is 97.2%, and the full-load efficiency is kept at 93.6%.
113 citations
"A High Step-up Transformer-Less DC-..." refers background in this paper
...As a consequence, these types of converters cannot produce high voltage output and their efficiency is low [14]....
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TL;DR: A new hybrid high voltage gain dc–dc converter is created by merging the standard boost converter with a coupled inductor and different switched-capacitor techniques, with a single switch and no requirement of higher duty cycle values.
Abstract: High step-up converters are required for distributed photovoltaic generation systems, due to the low voltage of the photovoltaic source. In this paper, a new hybrid high voltage gain dc–dc converter is created by merging the standard boost converter with a coupled inductor and different switched-capacitor techniques. With a single switch and no requirement of higher duty cycle values, the proposed converter achieves a high voltage gain and high efficiency, in addition to lowered voltage and current stresses of the components. A 200-W prototype was implemented experimentally to evaluate the converter, which reached a maximum efficiency of 97.6%.
110 citations
"A High Step-up Transformer-Less DC-..." refers background in this paper
...Extensive application of fossil fuels such as oil, coal, and gas has a major impact on environmental pollution and the greenhouse effect of the earth [1]....
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TL;DR: In this article, a high step-up dc-dc converter is proposed, which employs a coupled inductor and two voltage multipliers to increase the voltage gain and reduce the voltage stress on the main switch.
Abstract: A high step-up dc–dc converter is proposed in this paper. The presented converter benefits from some advantages such as high voltage gain and continuous input current, which makes it suitable for the renewable energy applications. The presented converter is based on the SEPIC converter. However, the converter voltage gain is improved by employing a coupled inductor and two voltage multipliers. A passive clamp circuit is also added to the proposed converter that increases the voltage gain and reduces the voltage stress on the main switch. Thus, a switch with low $R_{{\text{DS(on)}}}$ will be needed that decreases the conduction loss. Besides, the voltage stress on the output diode in the proposed converter is reduced, which alleviates reverse recovery problem. The steady-state analysis of the proposed converter is discussed in this paper. The analysis is verified with experimental results under the output power of 245 W.
106 citations