Analysis and Design of High-Efficiency Hybrid High Step-Up DC–DC Converter for Distributed PV Generation Systems
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%.
Citations
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TL;DR: In this paper, a single-switch, high step-up, dc-dc converter based on coupled-inductor with three winding and voltage multiplier cell to obtain a very highvoltage conversion ratio was introduced.
Abstract: This article introduces a single-switch, high step-up, dc–dc converter based on coupled-inductor with three winding and voltage multiplier cell to obtain a very high-voltage conversion ratio. A passive clamp circuit is applied in the converter to recycle the energy of leakage inductance and reduce voltage stress of the main power switch. This leads to utilize a power switch with low on-state resistance and low voltage rating that decreases the conduction losses. Several advantages include low operating duty cycle, high voltage conversion ratio, low turn ratio of the coupled inductor, leakage inductance reverse recovery, reduced voltage stress of semiconductors, alleviation of diodes reverse recovery issue and high efficiency, which make the presented topology appropriate for sustainable energy applications such as photovoltaic systems. The operation principle and steady-state analysis of the suggested topology in continuous conduction mode are expressed in detail. Also, design procedure and theoretical efficiency analysis of the proposed topology are presented. Moreover, a comparison study is performed to demonstrate the superiority of the presented converter over several similar recently proposed dc–dc converters. Finally, the proposed dc–dc converter feasibility and performance are justified through a fabricated 216-W laboratory prototype at 50 kHz switching frequency.
83 citations
Cites background from "Analysis and Design of High-Efficie..."
...Moreover, it is worth noting that the voltage gain of the converters suggested in [15]–[17], [24], and [31]...
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...The ripple of the input current is more than other presented high step-up converters such as the topologies presented in [17], [19]–[23], and [26]....
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TL;DR: In this paper, a coupled inductor-based high step-up dc-dc converter is proposed, which benefits from various advantages, namely ultrahigh voltage gain, low voltage stress on the power switches, and continuous input current with low ripple.
Abstract: In this article, a novel coupled inductor-based high step-up dc–dc converter is proposed. The introduced converter benefits from various advantages, namely ultrahigh voltage gain, low voltage stress on the power switches, and continuous input current with low ripple. Therefore, the presented converter is suitable for renewable energy applications. By utilizing clamped circuit, voltage spike of the active switch is clamped during the turn- off process. Hence, a switch with low $R_{\text{DS-on}}$ can be used, which reduces the conduction losses as well as the cost of the converter. Furthermore, the energy of leakage inductance is used to obtain zero voltage switching (ZVS) for the main and auxiliary switches. Additionally, the output diode current falling rate is controlled by leakage inductance; thus, reverse-recovery problem of output diode is alleviated. The steady-state analysis and design considerations of the proposed converter are discussed. Finally, a 250-W experimental prototype of the presented converter is implemented to validate the converter operation and the theoretical analysis.
55 citations
TL;DR: In this article, a new PWM resonant converter with a novel asymmetric modulation is proposed and verified, which eliminates hard switching turn-on losses from the rectifier, while maintaining the minimized number of components.
Abstract: In photovoltaic applications, many previous research works have focused on pulsewidth modulation (PWM) resonant converters in order to achieve a high efficiency with a wide input voltage range. Conventional approaches utilized symmetric boosting modulation at the secondary side rectifier to obtain a symmetric operation, and they utilized two boosting modes in a switching period. Among various rectifier structures, the voltage doubler structure has a strong advantage due to a small number of components. However, it suffers from serious hard switching losses in the secondary side rectifier. In this paper, a new converter with a novel asymmetrical modulation is proposed and verified. The strong point of the proposed converter is that it eliminates hard switching turn- on losses from the rectifier, while maintaining the minimized number of components. Although the proposed converter adopts an asymmetric modulation, the offset current on the transformer becomes zero inherently. Furthermore, a “forced half resonance” operation of the proposed converter keeps rms current stresses at the same level as conventional converter although it has a higher peak current. Accordingly, the proposed converter achieves a superior efficiency with the minimum number of components at 35–25 V input and 380 V/300 W output specification.
29 citations
TL;DR: In this article, a hybrid method is proposed that combines the stepwise weight analysis ratio assessment (SWARA) and full consistent method (FUCOM) weights that are represented as grey numbers used with traditional grey relational analysis (GRA) and evaluation based on distance from average solution (EDAS) methods.
Abstract: Selection of the most appropriate contractor for the installation of solar panels is essential to maximizing the benefit of this renewable, sustainable energy source. Solar energy is one of the 100% renewable energy sources, but implementation may not be very simple and cost-effective. A key phase in the implementation of renewable energy is the evaluation of contractors for the installation of solar panels, which is addressed as a multi-criteria decision-making (MCDM) problem. A new hybrid method is proposed that combines the stepwise weight analysis ratio assessment (SWARA) and full consistent method (FUCOM) weights that are represented as grey numbers used with traditional grey relational analysis (GRA) and evaluation based on distance from average solution (EDAS) methods. The ranking of contractors by both methods is the same, which confirmed the results presented in this research. The use of the grey SWARA-FUCOM weighting method combined with the GRA and EDAS methods increased the decision-makers’ (DMs) confidence in awarding the installation of the solar panel energy system to the top-ranked contractor.
27 citations
26 citations
Cites background from "Analysis and Design of High-Efficie..."
...As depicted in Figure 13, the presented converter normalized maximum diode voltage stress is lower than the other converters for any values of the duty cycle (except for Andrade et al19 and in the previous works22,23)....
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...It is important to note that the converters in Andrade et al19 and other studies22,23 have more components, remarkably lower voltage gain, and higher switch voltage stress than the suggested converter....
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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
"Analysis and Design of High-Efficie..." refers background in this paper
...However, due to the nonideality of the boost converter and its intrinsic resistance, conduction losses are higher when the duty cycle is higher, thus, affecting converter efficiency [7]–[9]....
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TL;DR: In this article, the authors provide an introduction, review, and framework for the category of high-step-up coupled-inductor boost converters, which are categorized into five groups according to the major topological features.
Abstract: High-step-up, high-efficiency, and cost-effective dc–dc converters, serving as an interfacing cell to boost the low-voltage output of renewable sources to the utility voltage level, are an important part in renewable energy systems. Over the past few years, there has been a substantial amount of studies devoted to high-step-up dc–dc converters. Among them, the category of coupled-inductor boost converters is widely researched and considered to be a promising solution for high-step-up applications. In this paper, these converters are categorized into five groups according to the major topological features. The derivation process, advantages, and disadvantages of these converters are systematically discussed, compared, and scrutinized. This paper aims to provide an introduction, review, and framework for the category of high-step-up coupled-inductor boost converters. General structures for the topologies are proposed to clarify the topological derivation process and to show potential gaps. Furthermore, challenges or directions are presented in this paper for deriving new topologies in this field.
325 citations
TL;DR: In this paper, the authors proposed a non-isolated high step-up dc-dc converter with dual coupled inductors suitable for distributed generation applications, which inherits shared input current with low ripple, which also requires small capacitive filter at its input.
Abstract: This paper introduces a non-isolated high step-up dc–dc converter with dual coupled inductors suitable for distributed generation applications. By implementing an input parallel connection, the proposed dc–dc structure inherits shared input current with low ripple, which also requires small capacitive filter at its input. Moreover, this topology can reach high voltage gain by using dual coupled inductors in series connection at the output stage. The proposed converter uses active clamp circuits with a shared clamp capacitor for the main switches. In addition to the active clamp circuit, the leakage energy is recycled to the output by using an integrated regenerative snubber. Indeed, these circuits allow soft-switching conditions, i.e., zero voltage switching and zero current switching for active and passive switching devices, respectively. The mentioned features along with a common ground connection of the input and output make the proposed topology a proper candidate for transformer-less grid-connected photovoltaic systems. The operating performance, analysis and mathematical derivations of the proposed dc–dc converter have been demonstrated in the paper. Moreover, the main features of the proposed converter have been verified through experimental results of a 1-kW laboratory prototype.
287 citations
TL;DR: An ultra-large voltage conversion ratio converter is proposed by integrating a switched-capacitor circuit with a coupled inductor technology, which has the reason for the high efficiency performance.
Abstract: An ultra-large voltage conversion ratio converter is proposed by integrating a switched-capacitor circuit with a coupled inductor technology. The proposed converter can be seen as an equivalent parallel connection to the load of a basic boost converter and a number of forward converters, each one containing a switched-capacitor circuit. All the stages are activated by the boost switch. A single active switch is required, with no need of extreme duty-ratio values. The leakage energy of the coupled inductor is recycled to the load. The inrush current problem of switched capacitors is restrained by the leakage inductance of the coupled-inductor. The above features are the reason for the high efficiency performance. The operating principles and steady state analyses of continuous, discontinuous and boundary conduction modes are discussed in detail. To verify the performance of the proposed converter, a 200 W/20 V to 400 V prototype was implemented. The maximum measured efficiency is 96.4%. The full load efficiency is 95.1%.
195 citations
"Analysis and Design of High-Efficie..." refers background or methods in this paper
...The CI [10]–[13] is a well-known technique for increasing the converter voltage gain....
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...In this Appendix, a comparative analysis of the proposed converter with boost converters [12], [13], and [16] is performed....
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...To overcome these disadvantages, switched-capacitor (SC) cells have recently become an attractive solution for dc–dc converters with high voltage gain [13]–[19]....
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...Despite its simplicity, this solution for the high voltage gain has some drawbacks, most of which are related to the leakage of the CI [10]–[13]....
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...To eliminate these problems and further increase the gain of these cells, a VM is inserted in the secondary of the CI (N2) [13], which consists of two capacitors Ca and Cb and two diodes Da and Db ....
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TL;DR: The steady-state analysis of the proposed dc–dc converter with high voltage gain is discussed and the proposed converter prototype circuit is implemented to justify the validity of the analysis.
Abstract: In this paper, a nonisolated dc–dc converter with high voltage gain is presented. Three diodes, three capacitors, an inductor, and a coupled inductor are employed in the presented converter. Since the inductor is connected to the input, the low input current ripple is achieved, which is important for tracking maximum power point of photovoltaic panels. The voltage stress across switch S is clamped by diode D 1 and capacitor C 1. Therefore, a main switch with low on-resistance RDS (on) can be employed to reduce the conduction loss. Besides, the main switch is turned on under zero current. This reduces the switching loss. The steady-state analysis of the proposed converter is discussed in this paper. Finally, the proposed converter prototype circuit is implemented to justify the validity of the analysis.
191 citations
"Analysis and Design of High-Efficie..." refers background in this paper
...In this Appendix, a comparative analysis of the proposed converter with boost converters [12], [13], and [16] is performed....
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...One of the simplest techniques to achieve a high voltage gain is to employ the turns ratio of some magnetic component, such as a coupled inductor (CI) or transformer [10]–[12]....
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...However, this has consequences, such as the leakage inductance (Lk ) increases, consequently, the energy entrapped in that inductance increases and deteriorates the efficiency of the system [12], and the losses in the core of the CI and copper increase....
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