Showing papers on "Voltage multiplier published in 2020"
TL;DR: The principle of operation, the theoretical analysis and the experimental results of a laboratory prototype for N(N2/N1) = 2 and n = 2 stage in about 260W with operating at 40kHz are provided.
Abstract: In this study, a new non-isolated high voltage gains dc/dc converter using coupled inductor and voltage multiplier techniques (diode/capacitor) is presented The voltage gain will be increased by increasing the turns ratio (N) and the number of stages of the VM units The proposed converter capable to more increase the output voltage gains with transfer energy which is stored in coupled inductance Also, the voltage multiplier unit causes to further increase in the output voltage level of the proposed converter Besides, the nominal value of the semiconductors is low due to these are clamped to the capacitors available on the voltage multiplier units The normalized voltage stress across the semiconductors is low which this case is compared in the comparison section Therefore, the power loss of switch can be reduced by using a switch with a lower rating (lower RDS(on)) and power diodes with the low nominal rating As a result, the overall efficiency of the proposed converter will be high To confirm the benefits of working in this paper, comparison results for different items with other works are provided in section 4 The principle of operation, the theoretical analysis and the experimental results of a laboratory prototype for N(N2/N1) = 2 and n = 2 stage in about 260W with operating at 40kHz are provided
137 citations
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
TL;DR: The IPOSB can attain high gain and lower output voltage ripples under a proper duty cycle, and the leakage energy of coupled inductor can also be recycled to the load, so the low voltage level MOSFETs can be adopted to reduce the losses and cost.
Abstract: This paper presents a hybrid cascaded boost converter, in which the input terminal is interlaced in parallel and the output capacitors embedded in voltage multiplier cells are interlaced in series at the output terminal [input parallel output series boost converter (IPOSB)]. The IPOSB can reduce the input current ripples because two primary windings of coupled inductors are connected in parallel with the cross. The voltage multiplier units combine with diode–capacitor and coupled inductor in the output side are charged and discharged in a series and parallel way. In addition, the leakage inductance of the coupled inductor inhibits the inrush current of the capacitors. Therefore, the IPOSB can attain high gain and lower output voltage ripples under a proper duty cycle, and the leakage energy of coupled inductor can also be recycled to the load. At the same time, the voltage stress of power devices is lowered, so the low voltage level MOSFETs can be adopted to reduce the losses and cost. Meanwhile, the soft switching performance of the zero-current-switching is fulfilled, which reduces effectively switching losses. The operational principle and steady-state performance of the converter are analyzed in detail. The correctness of the theoretical analysis is verified by setting up a 450-W experimental prototype.
74 citations
TL;DR: The proposed converter achieves a very high step-up voltage gain by using two coupled inductors and a voltage multiplier cell by utilizing the interleaved boost converter in the input side, and the input current is shared with low ripple.
Abstract: This paper proposes a new interleaved non-isolated high step-up dc-dc converter for interfacing renewable energy applications. The proposed converter achieves a very high step-up voltage gain by using two coupled inductors and a voltage multiplier cell. This topology utilizes the interleaved boost converter in the input side, and the input current is shared with low ripple. Moreover, a voltage multiplier cell with the secondary windings of the coupled inductors is employed in the output side to achieve the interleaved energy storage. The voltage stress on the semiconductor switches and the passive components is significantly reduced and lower than the output voltage. The aforementioned converter can be operated without an extreme duty cycle or a high turns ratio. The reverse recovery problem of the diodes is mitigated, and the leakage energy is recycled. Furthermore, by implementing low-voltage-rated MOSFETs with a small ON-resistance, the conduction losses can be reduced, and the efficiency can be improved. The topology is fed by a single input voltage, and the mathematical expression is methodically explored. The operation principle of the proposed converter and the comparison between the proposed converter with other topologies are discussed. The design, parameters selection, and experimental results are thoroughly introduced. A 32 to 800 V-dc is verified and simulated by using PLECS. Consequently, a 400 W hardware prototype is verified to validate the theory and the design.
65 citations
TL;DR: A new family of high gain step up dc-dc converter is proposed, but a generalized methodology to derive them from any classical dc-DC topology by applying a coupled inductor and voltage multiplier cells is proposed.
Abstract: Due to the plethora of non-isolated high gain step-up dc-dc converters presented in the literature, it has become important to comprehensively review and classify them, as well as to derive methods to generalize the usage of the commonly employed techniques. Motivated by this need, this paper not only proposes a new family of high gain step up dc-dc converter, but a generalized methodology to derive them from any classical dc-dc topology by applying a coupled inductor and voltage multiplier cells. For illustrating the methodology, high gain dc-dc converters based on the basic topologies (Buck, Boost, and Buck-Boost) are developed and analyzed. These converters are compared in terms of voltage gain, coupled inductor size, voltage stresses, total device rating, switching frequency effect in power loss, and output power regulation. Moreover, in order to verify the proposal, two practical experimentations are accomplished. Firstly, a prototype able to operate as any of the three basic topologies with different gain cells is developed for comparing theoretical, simulated, and experimental static gain results. Secondly, well-designed prototypes concerning to the Buck-, Boost-, and Buck-Boost-based converters are assembled for efficiency evaluation.
64 citations
TL;DR: In this paper, a novel high step-up interleaved dc-dc converter is presented, which is composed of an interleaving structure, an asymmetric voltage multiplier cell (AVMC), and a passive lossless clamped circuit.
Abstract: In this article, a novel high step-up interleaved dc–dc converter is presented, which is composed of an interleaved structure, an asymmetric voltage multiplier cell (AVMC), and a passive lossless clamped circuit. Compared to the classical interleaved boost converter, the proposed converter has a higher voltage gain owing to the employment of the AVMC and the coupled inductor. In addition, the input current ripple is limited to low values with the help of the interleaved structure, which gives more lifetime to the input power source. The voltage stresses of main switches are substantially low so that the MOSFETs with low voltage rate and ON-resistance ( $R_{\textrm {DS}(\mathrm{ON})} $ ) can be used. In addition, the voltage stresses and the reverse recovery problems of diodes are improved dramatically. Moreover, the zero current switching (ZCS) turn-on of switches and the ZCS turn-off of the clamp diodes are realized to reduce the switching losses. The leakage inductor energy is recycled and the voltage spikes are improved greatly by the passive lossless clamped circuit so that the efficiency can be upgraded further. Finally, a 400-W, 40-V-input, 400-V-output prototype is established to demonstrate the performance of this converter. The highest efficiency is about 97.3% and the full-load efficiency is approximately 97%.
58 citations
TL;DR: In this converter, coupled inductors and diode-capacitor voltage multiplier (VM) cells are utilized simultaneously to provide higher voltage gain, which increases the flexibility of the proposed converter.
Abstract: In this article, a new high step-up dc–dc converter with soft-switching capability is presented. In this converter, all of the main and the auxiliary power switches operate under soft-switching condition. In addition, the leakage inductances of the coupled inductors control the current falling rate of the power diodes. Therefore, the reverse recovery losses are reduced significantly. In addition, the voltage stresses across the power semiconductors and clamped capacitors are limited to lower values. In this converter, coupled inductors and diode-capacitor voltage multiplier (VM) cells are utilized simultaneously to provide higher voltage gain. This combination increases the flexibility of the proposed converter, because the turn ratios of the coupled inductors and the number of VM cells are the degrees of freedom which can be used to regulate the voltage stress across the semiconductors. In this article, detailed analysis, elements design, and comparison results are presented. Furthermore, in order to validate the theoretical analysis, a 500-W, 19–60-V/400-V laboratory prototype of the proposed converter is built, and the related results are investigate.
57 citations
TL;DR: An integrated interleaved dc–dc converter with ultrahigh voltage gain and reduced voltage stress based on the coupled-inductors and switched-capacitor circuits is proposed in this article, which is suitable for interfacing the low-voltage energy sources with a high- voltage dc bus in electric vehicle applications.
Abstract: An integrated interleaved dc–dc converter with ultrahigh voltage gain and reduced voltage stress based on the coupled-inductors and switched-capacitor circuits is proposed in this article, which is suitable for interfacing the low-voltage energy sources, such as fuel-cell, with a high-voltage dc bus in electric vehicle applications. Input-parallel connection of the coupled-inductors offers a reduced input current ripple and the current rating of components, as well as automatic input current sharing without a dedicated current sharing controller. A promising power-density improvement technique is given, in which only one magnetic core is utilized to implement two coupled-inductors that can provide the filter functionality, as well as transformer behavior. For suppressing the voltage ringing resulting from the leakage inductors, the active-clamp configuration is employed that can facilitate the soft-switching performance for all switches in a wide range of output power. A voltage multiplier stage is adapted to not only boost the voltage gain but help alleviate the reverse-recovery problem of diodes. The steady-state performance, theoretical analysis, and a comparison with the state-of-the-art converters are given in this article. Finally, the experimental results of a 1-kW, 100-kHz prototype are provided to confirm the validity of the proposed concept.
55 citations
TL;DR: This article proposes a novel step-up interleaved dc–dc converter that is suitable for renewable energy systems and the combination of coupled inductor and built-in transformer voltage multiplier cell gives an extra degree of freedom to increase the voltage gain.
Abstract: This article proposes a novel step-up interleaved dc–dc converter that is suitable for renewable energy systems. Coupled inductor and built-in transformer voltage multiplier cell are applied to extend the voltage gain while increasing the power density. Hence, the step-up ratio can be adjusted by the turns ratios of the coupled inductor and the built-in transformer. Compared with the other converters with only built-in transformer or only coupled inductor, the combination of these techniques gives an extra degree of freedom to increase the voltage gain. The configuration of the proposed converter not only reduces the current stress through the components, but also the input current ripple is maintained at low values that lengthen the life time of the renewable power source. The energy of the leakage inductors is successfully recycled and the high-voltage spikes across the power switches are avoided, which improves the conversion efficiency. Due to the reduced voltage stress, low-voltage power MOSFET s can be adopted for reduction of conduction losses and cost. The principle operation and steady-state analysis are given to explore the advantages of the proposed converter. Finally, a 1-kW prototype with 45–675 V voltage conversion is built to demonstrate the effectiveness of the proposed converter.
54 citations
TL;DR: In this article, a high step-up dc-dc converter with magnetic coupling-based voltage multiplier technique is proposed, which achieves high voltage gain and low switch voltage stress, which is beneficial for battery, fuel cell, and photovoltaic applications.
Abstract: A high step-up dc–dc converter is proposed in this article. With magnetic-coupling-based voltage multiplier technique, the proposed converter achieves high voltage gain and low switch voltage stress. Also, due to a boost inductor at the input, continuous input current is obtained, which is beneficial for battery, fuel cell, and photovoltaic applications. Moreover, zero voltage switching of the mosfet s is achieved, leading to low switching losses. Furthermore, zero dc bias of the coupled inductor is realized, resulting in small magnetic size and low core losses. The operation principles, performance analysis, and design considerations of the proposed converter are discussed. A prototype with 40-V input and 400-V output has been developed to verify the theoretical analysis.
52 citations
TL;DR: A high gain multiport dc–dc converter is proposed for low voltage battery-supercapacitor based hybrid energy storage systems, using a current-fed dual active bridge structure, thus providing galvanic isolation of the battery from the dc bus, wide zero voltage switching (ZVS) range of all the switches, and bidirectional power flow between any two ports.
Abstract: Interfacing multiple low-voltage energy storage devices with a high-voltage dc bus efficiently has always been a challenge. In this article, a high gain multiport dc–dc converter is proposed for low voltage battery-supercapacitor based hybrid energy storage systems. The proposed topology utilizes a current-fed dual active bridge structure, thus providing galvanic isolation of the battery from the dc bus, wide zero voltage switching (ZVS) range of all the switches, and bidirectional power flow between any two ports. The dc bus side bridge uses voltage multiplier cells to achieve a high voltage conversion ratio between the supercapacitor (SC) and the dc bus. Moreover, as the proposed topology employs only one two-winding transformer to achieve a three-port interface, the number of control variables are reduced, which decreases control complexities. The operation of the proposed converter is analyzed in detail, including the derivation of ZVS conditions for the switches and transformer power flow equations. A decoupled closed-loop control strategy is implemented for the dc bus voltage control and energy management of the storage devices under different operating conditions. A 1-kW laboratory prototype is built to verify the effectiveness of the proposed converter, along with the control scheme.
TL;DR: In this paper, closed-loop control and boundary condition for continuous conduction mode and discontinuous conduction modes of nonisolated inverting N× multilevel boost converter are articulated and the control strategy with saturation limiter is employed to achieve highly stable voltage.
Abstract: In this paper, closed-loop control and boundary condition for continuous conduction mode and discontinuous conduction mode of nonisolated inverting N × multilevel boost converter (MBC) are articulated. Inverting N × MBC combines the features of classical boost converter and voltage multiplier to attain inverting N times higher voltage. Consequently, the inverting N × MBC provides a viable solution for high-voltage step-up photovoltaic applications with low voltage rating reactive components and semiconductor devices. The control strategy with saturation limiter is employed to achieve highly stable voltage. The modes of operation, benefits of inverting N × MBC, and key factors for the selection of semiconductor devices and sizing of the reactive components are discussed. Additionally, the effects of reactive components and semiconductor devices on the output voltage are examined. Experimental results of the developed circuit are presented to validate the design of converter, and effectiveness and robustness of the implemented control algorithm for different input and output side perturbations.
TL;DR: In this article, the authors proposed a voltage multiplier topology that is a hybrid between a Cockcroft-Walton multiplier and a Dickson charge pump, which arranges some capacitors in parallel and others in series, thereby achieving low output voltage drop and low capacitor voltage stress at the same time.
Abstract: This paper presents a voltage multiplier topology that is a hybrid between a Cockcroft–Walton multiplier and a Dickson charge pump. The Cockcroft–Walton structure exhibits significant output voltage drop under load as the number of multiplier stage increases. This is because all coupling capacitors are connected in series. Dickson charge pump mitigates this issue by connecting all capacitors in parallel. But this solution comes at the expense of large capacitor voltage stress at the last multiplier stage. The proposed hybrid structure arranges some capacitors in parallel and others in series, thereby achieving low output voltage drop and low capacitor voltage stress at the same time. We develop a model that predicts hybrid multiplier's performance and validates it experimentally. We also demonstrate a 60–2.25 kV dc–dc converter based on a 16-stage hybrid voltage multiplier which achieves a voltage gain of 12.8 while keeping the highest capacitor voltage stress to 660 V.
TL;DR: A hybrid interleaved connecting boost converter with a wide step-up regulation range is proposed, which is suitable for the low-voltage distributed generation applications and can be operated in zero-current switching and full duty cycle range in theory.
Abstract: In this article, a hybrid interleaved connecting boost converter (HIBC) with a wide step-up regulation range is proposed, which is suitable for the low-voltage distributed generation applications. In the input of the HIBC, the primary windings of the double-coupled inductors are interleaved parallel connection, inheriting shared current and reduced current ripples. Then, the lossless passive clamped circuits are used to recycle the leakage energy of the coupled inductor and to reduce the voltage stress on the semiconductor devices to a very low level. The secondary windings of the coupled inductors are, respectively, combined with a capacitor–diode to form the two voltage multiplier units, which are again, respectively, connected with an output capacitor for a voltage-doubling module. These two voltage-doubling modules are connected in interleaved series for supplying power to the output, whose structure enhances the voltage gain greatly without adopting an extreme duty cycle and reduces the output voltage ripples. In addition, the main switches of the proposed converter can be operated in zero-current switching and full duty cycle range in theory, achieving a wide step-up regulation range with the high efficiency. Finally, the theoretical behaviors of the presented converter are described in detail and some experimental results are also shown to demonstrate the effectiveness of the proposed converter.
TL;DR: The features like continuous input current, low-input ripples, high voltage conversion ratio, and reduced stress on devices make the proposed converter more suitable for the voltage step-up applications, such as dc link, hybrid distribution systems, hybrid photovoltaic systems, etc.
Abstract: In this article, a new interleaved multilevel boost converter (interleaved-MBC) is suggested with minimal voltage multiplier (VM) cells for high-voltage step-up applications. The interleaved-MBC is derived in such a way that the maximum utilization of the VM circuit operation can be achieved by the interleaved structure. Furthermore, compared to existing multilevel interleaved converters, the reduced number of capacitors and diode with equal voltage rating makes it more attractive. Similar to the existing multilevel converter, the feature of the interleaved-MBC provides the extension of the number of levels to achieve the necessary voltages just by adding similar capacitor–diode stages (single capacitor and single diode are required to increase the stage by one). The features like continuous input current, low-input ripples, high voltage conversion ratio, and reduced stress on devices make the proposed converter more suitable for the voltage step-up applications, such as dc link, hybrid distribution systems, hybrid photovoltaic systems, etc. The detailed analysis of the converter is carried out by considering the nonidealities in the power circuit. The operation of the interleaved-MBC is presented for continuous and discontinuous conduction modes with boundary conditions. The components selection criterion and the comparison of converters are presented with suitable discussions. The converter is experimentally tested, and the obtained results validate its performance and functionality.
TL;DR: A comprehensive survey on the key components of a rectenna system, including antenna configurations, rectifier configurations, impedance matching networks, and RF filter, is outlined.
Abstract: In this paper, a comprehensive survey on the key components of a rectenna system, including antenna configurations, rectifier configurations, impedance matching networks, and RF filter, is outlined...
TL;DR: In this paper, the authors proposed two configurations for a non-isolated, high step-up, single-switch, coupled-inductor-based DC-DC converter, where a coupled inductor and voltage multiplier cells are used in the presented topologies to obtain a high voltage gain.
Abstract: This study proposes two configurations for a non-isolated, high step-up, single-switch, coupled-inductor-based DC–DC converter. A coupled inductor and voltage multiplier cells are used in the presented topologies to obtain a high voltage gain. Also, a passive clamp circuit is applied in the topologies to reduce voltage stress of the main power switch. This leads to utilising a power switch with lower on-state resistance, which decreases the conduction loss. Several advantages such as low operating duty cycle, high voltage conversion ratio, reduced voltage stress of semiconductors, low turn ratio of the coupled inductor, leakage inductance energy recovery and high efficiency operation make the presented structures appropriate for sustainable energy applications. The operational principle and steady-state analysis of the suggested topologies in continuous conduction mode are expressed in detail. Also, design procedure and theoretical efficiency of the topologies are presented. Then, the suggested topologies are compared with several similar high step-up topologies to prove their advantages. Finally, the performance and feasibility of the proposed DC–DC converter configurations are confirmed through experimental measurement results of 29 V input and 435 V/213 W and 480 V/238 W output laboratory prototypes at 50 kHz switching frequency.
TL;DR: In this article, a new high step-up dc–dc converter with zero voltage switching (ZVS) capability is presented for renewable energy applications and a combination of a coupled inductor and switched diode–capacitor voltage multiplier cells is used.
Abstract: In this article, a new high step-up dc–dc converter with zero voltage switching (ZVS) capability is presented for renewable energy applications. In order to achieve high voltage gain without extreme duty cycles or a high turns ratio, a combination of a coupled inductor and switched diode–capacitor voltage multiplier cells is used. In the presented converter, only an auxiliary winding with a diode that operates under zero current switching (ZCS) is utilized to realize ZVS for two power switches, and an active clamp circuit is utilized to reach ZVS for the other power switches. The leakage inductance of the coupled inductor controls the current falling rate of the voltage multiplier and output diodes, and also they turn- on under ZCS condition. Hence, reverse recovery losses of the diodes are reduced. The voltage stress on the power switches is low, and low voltage rating switches can be adapted to reduce the losses of their conduction. Finally, a 1-kW experimental prototype setup with 50 V input voltage and 470 V output voltage is built to verify the converter performance.
TL;DR: In this article, hybrid DC-DC non-isolated and non-inverting Nx Interleaved Multilevel Boost Converter (Nx-IMBC) is analyzed in Continuous Conduction Mode (CCM) and Discontinuous Conduction mode (DCM) with boundary condition and investigated in detail.
Abstract: In significant cases, the generated voltage needs to be step-up with high conversion ratio by using the DC-DC converter as per the requirement of the load. The drawbacks of traditional boost converter are it required high rating semiconductor devices and have high input current ripple, low efficiency, and reverse recovery voltage of the diodes. Recently, the family of Multilevel Boost Converter suggested and suitable configuration to overcome the above drawbacks. In this article, hybrid DC-DC non-isolated and non-inverting Nx Interleaved Multilevel Boost Converter (Nx-IMBC) is analyzed in Continuous Conduction Mode (CCM) and Discontinuous Conduction Mode (DCM) with boundary condition and investigated in detail. The Nx-IMBC circuit combined the features of traditional Interleaved Boost Converter (IBC) and Nx Multilevel Boost Converter (Nx-MBC). The modes of operation, design of Nx-IMBC and the effect of the internal resistance of components are presented. The comparison study with various recent DC-DC converters is presented. The experimental and simulation results are presented with or without perturbation in input voltage, output power and output reference voltage which validates the design, feasibility, and working of the converter.
TL;DR: In this article, a novel passive lossless clamped circuit composed of two capacitors and one diode is proposed, and the idea of using more capacitors in series instead of a single output capacitor to reduce voltage stress and volume is presented.
Abstract: In this article, a novel passive lossless clamped circuit composed of two capacitors and one diode is proposed. One of the two capacitors is used to construct a flowing path for the energy of leakage inductor and the other is used to store the leakage energy. Compared with a classical passive lossless clamped circuit, the novel circuit structure is more flexible and versatile, and the number of the extra capacitor and diode is consistent to the classical circuit for recycling the energy. Moreover, an idea of using more capacitors in series instead of a single output capacitor to reduce voltage stress and volume is presented. In order to extend their application scope and demonstrate their practical value, the novel clamped circuits and the idea are integrated into a family of cascade dc-dc converters based on the popular boosting cell, such as voltage-lift cell, symmetric voltage multiplier cell and asymmetric voltage multiplier cell. As a representative, a novel cascade converter, which integrates the novel passive lossless clamped circuit and the idea is analyzed in detail. The proposed converter has a high voltage gain and low ripple input current. The voltage stresses of an output diode and output capacitor can be effectively reduced. Its output capacitor adopts a 20-uF polypropylene (CBB) capacitor rated at 250 V to replace the higher rated electrolytic capacitor. A prototype circuit in the laboratory is established to verify its performances.
TL;DR: In this article, a novel interleaved high-step-up dc-dc converter with zero voltage switching (ZVS) is proposed, where all the power MOSFET s are switched with ZVS to minimize the switching losses of the proposed converter.
Abstract: This article proposes a novel interleaved high-step-up dc–dc converter with zero voltage switching (ZVS). Through a built-in transformer voltage multiplier cell (VMC) the high voltage conversion ratio is achieved without the narrow duty. By applying active clamp scheme, all of the power MOSFET s are switched with ZVS which minimizes the switching losses of the proposed converter. Besides the voltage stress across the switches is decreased and can be controlled by the built-in transformer turns ratio enabling utilization of low on -state resistance and low forward voltage drop semiconductors. Due to the interleaved structure, the input current ripple is minimized and the thermal stress is shared between the phases. Meanwhile, the charge balance of the capacitors give rise to equal current sharing performance for the two input inductors. All of these factors reduce the power losses and improves the performance of the proposed converter. Finally, in order to verify the operation of the proposed converter, a 35-V input voltage to 500-V output voltage prototype with the rated power of 1 kW is fabricated and tested in the laboratory.
TL;DR: Starting from a common principle, two new coupled-inductor-based dc–dc converters with large dc gains are proposed, which present a low voltage stress on the power switch with their leakage inductance energy recuperated to the load.
Abstract: Starting from a common principle, two new coupled-inductor-based dc–dc converters with large dc gains are proposed. Both of them present a low voltage stress on the power switch with their leakage inductance energy recuperated to the load. The first coupled-inductor-based converter employs two diode–capacitor voltage multipliers (VMs) inserted in an innovative way to give it many advantages. Specifically, the first VM is placed near the switch to serve as both a multiplier and a switch-voltage clamp cell, while the second one is inserted into the output circuit. The two VMs working in harmony then provide a very large dc gain. The conduction losses are also reduced as power switches with low ON-state resistance can be selected due to the clamping role of the first VM. Moreover, the availability of capacitors of both VMs in the output diode loop results in low voltage stress on all semiconductor devices. The choice of a lower voltage-rating output diode with a lower parasitic capacitance can then alleviate oscillations between the leakage inductance and diode capacitance at its turn-off. The second converter uses a three-winding coupled inductor and a single VM, forming a new hybrid VM cell. Its component count is reduced without affecting the practical dc gain. Its advantage is the elimination of the output diode recovery problem and thus does not result in spikes at its turn-off. Operational principles and dc steady-state analyses of the two converters are discussed, followed by comparison with available converters. The experimental results from two prototypes built for supplying a 400-V grid are given for validating the feasibility and theoretical analyses of the proposed converters.
TL;DR: The results clearly suggest that the proposed LVBM system is an efficient and self-starting energy harvester and storage for low-power generating MFCs.
Abstract: Although microbial fuel cells (MFCs) can produce renewable energy from wastewater, the generated power is practically unusable. To extract usable power from an MFC fed with wastewater, we newly developed a low voltage booster multiplier (LVBM), which is composed of a self-oscillating LVB and multistage voltage multiplier circuits (VMCs). The low output MFC voltage (ca. 0.4 V) was successfully boosted up to 99 ± 2 V, which was the highest voltage that has been ever reported, without voltage reversal by connecting an LVB with 20-stage VMCs. Moreover, the boosted voltage (81 ± 1 V) was stably maintained for > 40 h even after disconnecting the LVBM from the MFC. The energy harvesting efficiency of LVBM was > 80% when an LVB with 4-stage VMCs was charged to 9.3 V. These results clearly suggest that the proposed LVBM system is an efficient and self-starting energy harvester and storage for low-power generating MFCs.
TL;DR: The proposed non-isolated high step-up DC/DC converter combines the advantages of switched capacitors, coupling inductors, and voltage multiplier techniques to achieve high voltage gain without operating at maximum duty cycle.
Abstract: In this paper, a high-efficiency DC/DC converter with low voltage stress is designed for green power applications. The proposed non-isolated high step-up DC/DC converter combines the advantages of switched capacitors, coupling inductors, and voltage multiplier techniques. Adding the cells of the switched capacitor not only increases the voltage gain but reduces the voltage stress of the semiconductor devices. High voltage gain can be achieved by adding a coupled inductor method to adjust the turns ratio. When these are combined with a voltage multiplier circuit, the leakage energy of the coupled inductor is recirculated to the output terminal with lossless passive clamping performance. The leakage inductance of the coupled inductor controls the current dropping rate of the output diode turn OFF so that the reverse-recovery problem is mitigated. The proposed converter integrates these three techniques to achieve high voltage gain without operating at maximum duty cycle. In addition, switching loss reduction is realized through zero current switching turn ON soft switching performance with low voltage stress of semiconductor devices. Finally, this paper verifies the performance of the proposed converter for theoretical analysis by using a $35\sim 45\text{V}$ input, 380V output, and 1kW power prototype circuit.
TL;DR: An improved LLC resonant converter with reconfigurable hybrid voltage multiplier for wide output voltage range applications by adopting three legs and two active switches, which can be reconfigured to three configurations, covering the range of more than three times of the minimum output voltage.
Abstract: This paper proposes an improved LLC resonant converter with reconfigurable hybrid voltage multiplier for wide output voltage range applications. By adopting three legs and two active switches, the rectifier can be reconfigured to three configurations, i.e., full-bridge rectifier, hybrid voltage-multiplier rectifier and voltage-multiplier rectifier, covering the range of more than three times of the minimum output voltage. Compared with conventional LLC converter, the operating range of each configuration is narrowed so that the magnetizing inductance is optimized and switching frequency range is narrowed to achieve higher efficiency. Pulsewidth plus pulse-frequency modulation strategy is employed to achieve smooth transition between these operation modes. Zero-voltage switching of all power mosfet s and zero-current switching of all secondary-side diodes are achieved as well. Detailed operational principles, characteristics, design consideration, and control stagey of the proposed converter are analyzed. A 3.3 kW 150–450 V output prototype is built and tested to verify the effectiveness and advantages of the proposed converter.
TL;DR: In this article, a single source transformer-less boost multilevel inverter topology is proposed and the experimental results along with the MATLAB/Simulink results are presented to validate the efficacy of the proposed converter.
Abstract: In this article, a single source transformer-less boost multilevel inverter topology is proposed. The salient features of the proposed topology include voltage boost capability, reduced number of switches, and requirement of a single dc voltage source, which in turn reduces the overall cost and complexity. The proposed topology comprises a conventional boost converter and a diode–capacitor voltage multiplier circuit (VMC). The capacitors’ voltages of the VMC are self-balanced, which eliminates the requirement of any auxiliary circuit for capacitor voltage balancing. Moreover, due to the input inductor, it has less input current ripple and able to provide variable fractional voltage gain, which is a key requirement for maximum power point tracking in photovoltaic applications. In order to get an optimal harmonic profile of the output ac voltage, a fundamental frequency switching technique named as the fundamental frequency sine quantization method is adopted for the generation of the switching signals. Finally, a hardware prototype of the proposed 11-level boost inverter is developed and the experimental results along with the MATLAB/Simulink results are presented to validate the efficacy of the proposed converter.
TL;DR: In this paper, a new transformerless boost-based DC-DC converter is proposed, which employs a charge-pump circuit and n-stages of voltage multiplier cells (VMC).
Abstract: A new transformer-less boost-based DC–DC converter is suggested in this research. The voltage gain of the proposed converter is enhanced employing a charge-pump circuit (CPC) and n-stages of voltage multiplier cells (VMC). Each VMC consists of one inductor, one diode, and two capacitors. As the number of these VMC stages (n) increases, it is feasible to achieve high voltage gains with low duty cycles. Furthermore, by expanding n, a significant reduction of the normalized peak voltage stress (NPVS) of the components is possible. Due to this feature, using the MOSFET switches with low ON-state resistance and the low-rating voltage components is provided which results in diminishing the conduction and switching losses. The steady-state analysis is accomplished in details and the comparison considering other converters in the literature is presented in this manuscript. Validating of the converter performance is accomplished by implementing a laboratory prototype for the power of 300 W, input, and output voltages of 30 V and 310 V, respectively, and switching frequency of 40 kHz. Experimental results validate the mathematical analysis.
TL;DR: In this paper, the authors proposed a non-isolated Single-Switch Quadratic Boost Coupled-Inductor (SSQBCI) DC/DC converter with continuous input current and low voltage stress on the switching component.
Abstract: In this paper, a novel non-isolated Single-Switch Quadratic Boost Coupled-Inductor (SSQBCI) DC/DC converter with continuous input current and low voltage stress on the switching component is presented. The suggested structure is based on the traditional quadratic boost converter. In this new topology, to achieve an ultra-high voltage gain without large duty cycle, a Coupled-Inductor (CI) along with a Voltage Multiplier (VM) are employed. The magnetic energy stored in the leakage inductor of the CI is recycled by a regenerative passive clamp capacitor that is connected with the switch in parallel, which helps to limit the maximum voltage across the switch. Therefore, to reduce the switch conduction loss and improve the efficiency, a switch with the low static drain-to-source ON-resistance can be used. Moreover, the low voltage stress on the output side diode alleviates the reverse recovery loss. The steady-state operating principle, comparisons with other related topologies and also design considerations in Continuous Conduction Mode (CCM) will be analyzed in detail. Finally, the performance of the proposed SSQBCI is verified by experimental results using a prototype with 30V input and 200V - 160 W output operation at a constant switching frequency 50 kHz.
TL;DR: A new high voltage gain DC–DC converter using a coupled inductor and VM cell using a passive clamp circuit to reduce the voltage stress on the MOSFET switch, which helps to improve the voltage gain of the converter.
Abstract: Nowadays, with the high-power demand in industries, the need for high step-up converters has been a crucial part of interest. Power conservation is an essential aspect of innovation leading to improving the voltage gain of conventional converters such as boost, Cuk and SEPIC. Boosting techniques including voltage multiplier (VM) cells, voltage lift capacitors, coupled inductors, switched capacitor/inductor, etc., are used to enhance the conventional converters to meet high-voltage requirements of various applications. This paper proposes a new high voltage gain DC–DC converter using a coupled inductor and VM cell. The operation of the converter is based on charging the capacitor using a single MOSFET switch and adding it in series with the source to the load. Besides, a passive clamp circuit which is comprised of capacitor and diode has been selected over the active clamp to reduce the voltage stress on the MOSFET switch, which helps to improve the voltage gain of the converter. The turns ratio of the coupled inductor is chosen appropriately to get the required voltage gain. Reduction in voltage stress results in selecting MOSFET with small on-state resistance (Rds-on), which offers less conduction loss and high efficiency of the converter. The proposed converter is modeled, analyzed and simulated using PLECS simulation software. The results are experimentally verified by developing 150 W experimental prototype.
TL;DR: Operation quality factors such as voltage stress, voltage gain, efficiency, dynamic of the converter and operation in transient conditions are investigated using the experiments.
Abstract: This study proposes a high step-up DC–DC converter based on quadratic boost converter. The proposed converter is composed of a quadratic boost converter and a multiplier cell. The converter can be used in low power applications which need to increase output voltage with high gain. In order to reduce number of the components, the multiplier cell is composed with the quadratic boost converter in a way to share one of their inductors. The found location of the multiplier adds some advantages to the proposed converter in comparison to the similar converters. The converter advantages include higher voltage gain, lower voltage stress on diodes and capacitors and requiring smaller inductors. To verify the points, principle operation of the converter is analysed and it has been compared with other converters. The proposed converter is designed and implemented using its main equations. Experiments are done along the lines of the analysis to prove that they have good accordance with each other. Operation quality factors such as voltage stress, voltage gain, efficiency, dynamic of the converter and operation in transient conditions are investigated using the experiments.