Static Voltage Gain Research Articles

Design and implementation of switched capacitor-based high gain converter

ABSTRACT This paper suggests a high gain Active Switched Capacitor, Switched Inductor, and Voltage Multiplier (ASC-SI-VM) based transformerless DC-DC boost converter to improve the static voltage gain, decrease the voltage stress and current stress of semiconductor devices and accomplish maximum efficiency. The switched inductor cell ensures a continuous source current, and the multiplier cell boosts the output voltage. The voltage conversion ratio analysis, stress expressions and power loss analysis of all the devices are derived. Comparisons are made between the proposed ASC-SI-VM converter topology and existing topologies in terms of static gain, voltage and current stress, and component count. The efficiency of 94.01% is attained for a 20 V/200 V voltage rating and a rated power of 100 W. The experimental topology of the proposed ASC-SI-VM converter is created to confirm the simulated and theoretical values.

Superionic fluoride gate dielectrics with low diffusion barrier for two-dimensional electronics.

Exploration of new dielectrics with a large capacitive coupling is an essential topic in modern electronics when conventional dielectrics suffer from the leakage issue near the breakdown limit. Here, to address this looming challenge, we demonstrate that rare-earth metal fluorides with extremely low ion migration barriers can generally exhibit an excellent capacitive coupling over 20 μF cm-2 (with an equivalent oxide thickness of ~0.15 nm and a large effective dielectric constant near 30) and great compatibility with scalable device manufacturing processes. Such a static dielectric capability of superionic fluorides is exemplified by MoS2 transistors exhibiting high on/off current ratios over 108, ultralow subthreshold swing of 65 mV dec-1 and ultralow leakage current density of ~10-6 A cm-2. Therefore, the fluoride-gated logic inverters can achieve notably higher static voltage gain values (surpassing ~167) compared with a conventional dielectric. Furthermore, the application of fluoride gating enables the demonstration of NAND, NOR, AND and OR logic circuits with low static energy consumption. In particular, the superconductor-insulator transition at the clean-limit Bi2Sr2CaCu2O8+δ can also be realized through fluoride gating. Our findings highlight fluoride dielectrics as a pioneering platform for advanced electronic applications and for tailoring emergent electronic states in condensed matter.

SEPIC-Boost-Based Unidirectional PFC Rectifier with Wide Output Voltage Range

A novel unidirectional hybrid PFC rectifier topology based on SEPIC and boost converters is proposed, which is applicable to various industrial applications such as electric vehicle charging stations, variable speed AC drives, and energy storage systems. Compared to other rectifiers, the proposed SEPIC-boost-based rectifier exhibits continuous current on the AC side, lower voltage stress on the active switches, a wider range of DC output voltage, no auxiliary DC-DC converters, and a high step-up static voltage gain operating with low input voltage and a low step-up static gain for the high-input-voltage operation. These traits allow the SEPIC-boost-based rectifier to utilize smaller input-side harmonic filtering inductors and adopt active switches with lower voltage ratings, resulting in reduced conduction losses. Additionally, the proposed rectifier features power factor correction and high boost/buck voltage-gain capabilities, simplifying control for electric vehicle charging and expanding its range of applications. In this paper, the operating principle of the novel topology is presented first, and then the mathematical model of the proposed rectifier is built. Based on this, the comparison between the proposed topology and conventional boost and SEPIC converters is given. Furthermore, the control strategy, including the high-power-factor control and the balancing control to the DC capacitor voltages, is discussed. Finally, to validate the accuracy of the proposed rectifier’s theoretical research, a 500-W SEPIC-boost rectifier system has been constructed in the laboratory, generating a 200/120 Vdc output voltage from a 155 Vpk/50 Hz power source.

Performance numerical evaluation of modified single-ended primary-inductor converter for photovoltaic systems

<span lang="EN-US">Single-ended primary-inductor converter (SEPIC) was considered a good alternative to a DC-DC converter for photovoltaic (PV) systems. The SEPIC converter can operate with an input voltage greater or less than the regulated output voltage, or as a step-up or step-down. As a step-up converter, SEPIC boosts PV voltage to specific levels. However, gain limitation and voltage stress continue to reduce the efficiency of conventional SEPIC converters. Because of this, researchers created a modified SEPIC converter to improve performance. In this paper, six modified SEPIC converters were compared and evaluated. To compare fairly, all modified SEPIC converters are non-isolated and use a single switch. Power simulator (PSIM) software was used to simulate each converter with a BISOL BMO-250 PV module and maximum power point tracking (MPPT) P&O controller. The converter with the highest static voltage gain and lowest duty cycle has been identified. It results in up to ten times voltage increment with a 0.8-duty ratio. All topologies have the same voltage stress, with maximum and minimum values of 30.1 and 29.5 V, respectively. On the other hand, each topology produces different average efficiencies, with the highest and lowest efficiency at 99.5% and 97.2%, respectively.</span>

A Two-Switch SEPIC-Based Nonisolated Three-Port Converter Featuring High Step-Up Gain for Solar PV Applications

A two-switch nonisolated DC–DC three-port converter (TPC) based on a modified SEPIC circuit with a high voltage gain is introduced and a unified power control strategy is proposed in this article. The proposed TPC is integrated with one low-voltage input and one high-voltage port and is suitable for photovoltaic (PV) applications. The operating principle of this TPC is analyzed in detail and then its static voltage gain is determined. In addition, the advantage of using a modified SEPIC circuit is that fewer components are employed compared to a similar topology. Furthermore, the state space method is adopted to analyze this multiple-input multiple-output (MIMO) system and then a small signal model is built to design an appropriate control strategy. Finally, the proposed 100 W TPC connects a solar PV energy storage system to a load demonstrating efficiency ranging from 85% to 94%. Moreover, the steady- and dynamic-state performances of this TPC are verified in the SimStar MT3200 HIL platform, which illustrates the feasibility of the proposed TPC and its power control strategy for solar PV applications.

Three-Mode Variable-Frequency ZVS Modulation for Four-Switch Buck+Boost Converters With Ultra-High Efficiency

This article introduces a three-mode variable-frequency zero-voltage switching (ZVS) modulation method for the four-switch buck+boost converter. This method makes this circuit concept well suited for applications, such as wireless power charging of electric vehicles, where this circuit operates as a power buffer between the resonant converter and the battery with the function to implement the required charging profile. Herein, the buck+boost converter operation is subdivided into three operating regions according to the converter static voltage gain, i.e., buck-, buck-boost- and boost-type modes. A ZVS turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> triangular current mode (TCM) control is adopted for buck-type and boost-type modes. In the buck-boost-type mode when the input-to-output voltage gain is close to unit, all the possible modulation cases are studied thoroughly based on the phase shift of the two half bridges in a full switching period. The selection of the most suitable modulation scheme is performed to minimize the rms value of the inductor current while taking into account the simplification of the practical implementation. Closed-form equations are derived, which makes it easy to implement in practice. The proposed strategy is described, analyzed, and finally verified through a 3 kW surface mounted device (SMD) silicon carbide (SiC) <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> -based laboratory prototype with designed input voltage of 300–600 V and the typical output voltage of 400 V class battery. The efficiency from the measured results is remarkably high, i.e., between 99.2% and 99.6% in a power range from 1 to 3 kW. Finally, tests for the operating mode transitions demonstrated the feasibility of the proposed modulation method. The power density of this converter is 4.86 kW/L.

A Transformerless Boost-Modified Cuk Combined Single-Switch DC-DC Converter Topology with Enhanced Voltage Gain

HIGHLIGHTS Single-switch configuration for the proposed hybrid converter is employed. Static voltage gain of the proposed hybrid topology is improved. Power switch is subjected to low voltage-current stress. The power conversion efficiency of the proposed converter is improved.

Use of Boost Power Stage for Static Voltage Gain Improvement of a Non-isolated Continuous Input Current Three-Level DC-DC Converter

The work presented in this paper describes the steady state analysis of a non-isolated and continuous conduction mode (CCM) operated three-level DC-DC converter with input boost power stage for achieving high static voltage gain. The proposed converter configuration is a double boost DC-DC conversion scheme. A boost power module consisting of a power switch, an inductor, a pre-charge diode, and a diode rectifier is introduced as the input stage in the conventional three-level DC-DC converter configuration to obtain the DC-DC converter topology suggested in this research work. The role of the input boost power stage is to extend the voltage gain of the conventional three-level boost converter. The proposed topology employs two power switches in addition to a boost power switch with simple control strategy so that the switching losses are reduced. The switches are subjected to low voltage and current stresses. The suggested non-isolated converter is operated under continuous inductor current mode in open loop configuration. The converter configuration has been simulated in MATLAB / SIMULINK platform. The input boost power stage receives a voltage of 24 V from a DC source. With low duty ratio (= 0.8) of the power switches, a DC voltage of around 208 V is obtained at the load end. The passive components of the converter are so designed that the filtering requirements on the DC output voltage and current waveforms are reduced. The voltage gain of the proposed converter is compared with that of the three-level boost converter without input boost power stage. The various modes of operation of the suggested converter are discussed with relevant equivalent circuits. The proposed system is validated using a developed hardware prototype model of 100 W converter with a low cost KA3525A PWM controller. Both simulation and prototype model results demonstrate that the proposed converter suits high voltage gain applications.

Improvement of Static Voltage Gain of a Non-Isolated Positive Output Single-Switch DC-DC Converter Structure Using a Diode-Capacitor Cell

There are different low switching stress non-isolated DC-DC power converter structures developed for Photo-Voltaic (PV) applications with a view to achieve high voltage conversion ratio. The work proposed in this research article investigates the performance analysis of a coupled inductor and diode-capacitor multiplier cell based non-isolated high gain single-switch DC–DC conversion scheme with a single-ended primary-inductor on the input side. The presented converter suitable for renewable energy applications has the merits such as continuous input current, high voltage conversion ratio, and reduced voltage stress across the power switch. The multiplier cell consisting of two diodes and two capacitors is mainly used to enhance the converter output voltage level. A MATLAB / SIMULINK model of the suggested topology has been developed to validate its performance. During the simulation of the converter, a DC voltage of 50 V was given at the input side. The load end received a DC voltage of approximately 900 V. Thus, through this study, it was found that the addition of diode-capacitor cell can significantly improve the static gain of the suggested converter. The findings of this research may serve as a base for future studies on improvement of voltage gain of DC-DC converters.

Steady State Behavior of a Single-Switch Non-isolated DC-DC SEPIC Converter Topology with Improved Static Voltage Gain

This paper presents the analysis of steady state behavior of a single switch non-isolated Single Ended Primary Inductance Converter (SEPIC) topology for achieving high DC voltage gain using diode-capacitor voltage multiplier. A voltage boosting module consisting of inductor and capacitor in addition with two diodes is introduced in the conventional SEPIC configuration in order to derive the DC-DC conversion technology proposed in this work. The voltage gain of the converter is extended using a diode-capacitor voltage multiplier cell. The converter suggested in this work has a single controlled switch. Hence, the conduction losses and the control complexity of the switch are very much reduced. The open loop configuration of the proposed non-isolated converter is described under continuous inductor current mode. The voltage boosting capability of the presented converter is compared with that of the existing modified SEPIC structure. The presented positive output converter topology has low switch voltage-current stress compared to the existing modified SEPIC topology given in the literature. The inductor and capacitor components of the suggested converter are so chosen that the DC output voltage and current waveforms show very low percentage of ripples. A DC voltage level of 24 V is given as input to the proposed converter. The DC voltage obtained across the load terminals is around 370 V which is achievable with low duty ratio (= 0.7) of the active switch. The voltage conversion ratio is very much influenced by the variation of the duty cycle of the power switch. In this work, the converter topology is presented and its various modes of operation are explained with equivalent circuits. The PSIM software platform is effectively and efficiently utilized to validate the performance of the converter. The obtained results convey that the proposed DC-DC conversion technology with extended voltage gain has the capability to maintain the steady-state output voltage and current profiles with almost negligible amount of ripples owing to the use of suitably designed non-dissipative elements in LC filter.

Simulation and Steady State Analysis of a Non-isolated Diode Rectifier-fed DC-DC Boost Converter with High Static Voltage Gain

This paper presents the simulation and analysis of a non-isolated step-up DC-DC converter operating in continuous inductor current mode with fixed switching frequency. The proposed converter proves better steady state performance in terms of improved voltage gain compared to the conventional boost configuration. The suggested two stage converter topology is fed by an uncontrolled diode bridge rectifier for which the sinusoidal input AC voltage is (50/ 2 ) V (rms). The design of the converter is such that the input AC voltage of (50/ 2 ) V (rms) is stepped up to around 256 V (DC) at the load end for the duty ratio value of 0.8. The performance of the proposed converter configuration is validated through simulation in Matlab/Simulink platform. The open-loop configuration provides higher constant output voltage profile compared to the conventional boost topology. The output voltage and current profiles show reduced settling time with almost no overshoot. The output voltage ripple is reduced to lower value. The suggested configuration ensures that the voltage-current stress across the switches is also reduced.

Flexible Complementary Oxide Thin-Film Transistor-Based Inverter With High Gain

Wearable bio-sensing devices are considered promising for ubiquitous heath monitoring. To accurately read out small bio-signals, the development of high-performance flexible front-end circuits is crucial. Oxide semiconductors are considered one of the most promising active channel materials for on-polymeric-foil electronics. In this article, a high-gain flexible complementary metal–oxide–semiconductor (CMOS) inverter with a beta ratio of 1, a desirable feature for device miniaturization, was demonstrated by monolithically integrating a top-gated n-type indium gallium zinc oxide (IGZO) thin-film transistor (TFT) and a bottom-gated p-type SnO TFT on a 5.5- $\mu \text{m}$ -thick polyimide substrate. The influence of atomic layer deposited (ALD)-HfO2 capping layer on the properties of oxide active channels has been analyzed. The flexible inverter exhibited a high static voltage gain of 370 V/V and balanced noise margins (noise margin high of 4.8 V, noise margin low of 4.7 V) for a supply voltage of 10 V. In addition, the voltage transfer characteristics remained virtually unchanged when the device was subjected to an outward or an inward bending radius of 2.5 mm, indicating the complementary oxide-TFT-based inverter is practical for flexible electronics applications.

Isolated boost converter based high step‐up topologies for PV microinverter applications

In this study, a family of isolated boost DC–DC converters is proposed and evaluated. This family is built by the combination of an isolated current fed converter with high-voltage gain techniques. The evaluated cells are switched inductor, switched capacitors, reduced redundant power processing and a mixed of switched inductor and switched. So, the proposed family has four different isolated high step-up DC–DC converters. To evaluate this family, a comparative study of the significant features was performed. This study comprises features such as principle of operation, derivation of static voltage gain, current and voltage stress on the components, component stress factor, number of components, power losses, power density and cost. By these evaluations, the key features, limitations and restrictions of each converter were acknowledged. In this way, one can gather all the theoretical knowledge of each of the analysed converters and estimate which one will have better performance in the laboratory. To validate the theoretical analysis, four prototypes were built according to PV AC-module specifications 200 W.

Comparative Evaluation of Single Switch High-Voltage Step-Up Topologies Based on Boost and Zeta PWM Cells

This paper presents a comparative evaluation of eight high-voltage step-up converters based on different associations of boost and zeta standard dc–dc pulse width modulation (PWM) cells. These eight converters present different characteristics such as cascaded and stacked PWM cell associations, as well as isolated winding coupled inductors, tapped winding coupled inductors, and noncoupled inductors. In order to explore the advantages and address the limitations of each topology, several comparative evaluations concerning static voltage gain, power losses, current and voltage stresses, component stress factors, power density, relative cost, and efficiency were carried out. From the theoretical analysis and experimental results, the association named stacked boost–zeta with autotransformer yielded the highest efficiency and power density and resulted in the most attractive converter for the case study.

A New Combined Boost Converter with Improved Voltage Gain as a Battery-Powered Front-End Interface for Automotive Audio Amplifiers

High boost DC/DC voltage conversion is always indispensable in a power electronic interface of certain battery-powered electrical equipment. However, a conventional boost converter works for a wide duty cycle for such high voltage gain, which increases power consumption and has low reliability problems. In order to solve this issue, a new battery-powered combined boost converter with an interleaved structure consisting of two phases used in automotive audio amplifier is presented. The first phase uses a conventional boost converter; the second phase employs the inverted type. With this architecture, a higher boost voltage gain is able to be achieved. A derivation of the operating principles of the converter, analyses of its topology, as well as a closed-loop control designs are performed in this study. Furthermore, simulations and experiments are also performed using input voltage of 12 V for a 120 W circuit. A reasonable duty cycle is selected to reach output voltage of 60 V, which corresponds to static voltage gain of five. The converter achieves a maximum measured conversion efficiency of 98.7% and the full load efficiency of 89.1%.

An integrated Boost-Sepic-Ćuk DC-DC converter with high voltage ratio and reduced input current ripple

This paper proposes a new non-isolated DC-DC converter for photovoltaic application. This converter topology is based on dual stage integration. In first stage conventional boost topology is integrated with Self-Lift Sepic converter. This topology is then integrated with Ćuk converter. The first stage provides a high static voltage gain and reduced voltage stress across the single switch facilitating the use low rating switch resulting in low conduction losses. The second stage further aids the high static voltage gain. There is reduced voltage stress across the diodes too, encouraging the use of Schottky diodes for eliminating the problem of reverse recovery time resulting in further reduction of conduction losses. This paper presents design consideration of new topology and stated characteristics are verified by simulation.

Low-Temperature, Solution-Processed, 3-D Complementary Organic FETs on Flexible Substrate

Vertical stacking of thin-film transistors is an effective way to reduce the footprint of a device, thus increases transistor density in complex flexible electronic applications without reducing the feature size and resolution of the patterning tools. In this paper, we report a 3-D complementary organic FET fabricated on a plastic substrate by stacking a bottom-gate top-contact p-type transistor on a top-gate bottom-contact n-type transistor with a gate shared between the two. We used high-performance polymer semiconductors, poly [(E)-2, 7-bis (2 decyltetradecyl) 4 methyl 9 (5 (2 (5 methylthiophen 2 yl) vinyl) thiophen 2 yl) benzo [lmn] [3, 8] phenanthroline-1, 3, 6, 8 (2H, 7H)-tetraone] for n-type devices and poly [2, 5-bis (7-decylnonadecyl) pyrrolo [3, 4-c] pyrrole-1, 4 (2H, 5H)-dione-(E) 1,2 bis (5 (thiophen 2 yl) selenophen 2 yl) ethene] for p-type devices to fabricate the vertically stacked organic transistors along with a Cytop and cross-linked poly (4-vinylphenol) bilayer and Poly (Methyl Methacrylate) gate dielectric. A 3-D flexible complementary organic inverter exhibits a maximum static voltage gain of $\thickapprox 18$ V/V and high noise immunity of up to 60% of ${V} _{\mathrm {DD}}$ /2. The 3-D transistors show hysteresis-free $I$ – $V$ characteristics despite of low-temperature processes. Moreover, we discuss the influence of cross-linker concentration and the processing temperature of the PVP dielectric film on the degree of hysteresis in $I$ – $V$ characteristics.

Flexible Complementary Oxide–Semiconductor-Based Circuits Employing n-Channel ZnO and p-Channel SnO Thin-Film Transistors

In this letter, we report flexible fully oxide-based complementary metal–oxide–semiconductor (CMOS) inverters and ring oscillators by the monolithic integration of flexible n-channel zinc oxide (ZnO) and p-channel tin monoxide (SnO) thin-film transistors (TFTs). Inverted-staggered bottom-gated TFTs were fabricated by a low-temperature RF-sputtering technique. The static voltage gain of a flexible oxide-TFT-based CMOS inverter with a geometric aspect ratio of 5 is $\sim 12$ at a supplied voltage ( $\text{V}_{\mathrm {DD}}$ ) of 12 V. An oscillation frequency of $\sim 18.4$ kHz is obtained from a five-stage flexible oxide-TFT-based CMOS voltage control ring oscillator at $\text{V}_{\mathrm {DD}}$ of 12 V. Degradations of TFTs, inverters, and ring oscillators have been observed when a mechanical tensile strain is applied, whereas the influence of compressive strain is negligible.