Large Voltage Gain Research Articles

A large voltage gain and high output power boost converter for PV sources directly convertible to 400V DC microgrid

A large voltage gain and high output power boost converter for PV sources directly convertible to 400V DC microgrid

Derivation of Ultra-High Gain Hybrid Converter Families for HASEL Actuators Used in Soft Mobile Robots.

This work proposes, analyzes, designs, and validates superior topologies of UHGH converters that are capable of supporting extremely large conversion ratios up to ∼2000× and output voltage up to ∼4-12 kV for future mobile soft robots from an input voltage as low as the range of a 1-cell battery pack. Thus, the converter makes soft robots standalone systems that can be untethered and mobile. The extremely large voltage gain is enabled by a unique hybrid combination of a high-gain switched magnetic element (HGSME) and a capacitor-based voltage multiplier rectifier (CVMR) that, together, achieve small overall size, efficient operation, and output voltage regulation and shaping with simple duty-cycle modulation. With superior performance, power density, and compact size, the UHGH converters prove to be a promising candidate for future untethered soft robots.

An asymmetrically controlled sense amplifier with boosted sensing voltage difference for low-voltage and high-density DRAM

The transistor threshold voltage mismatch and sensing noise are larger with technology scaling, while the sensing voltage difference of bit-line sense amplifier becomes smaller. Though various offset calibration techniques have been adopted in bit-line sense amplifiers to compensate for the offset mismatch, sensing offset and noise are still critical issues to limit the sensing margin. This brief proposes a bit-line sense amplifier with asymmetrically controlled isolation devices to solve the sensing offset and sensing noise problems simultaneously. Being biased to the calibration point, the target inverter acts as an amplifier with a large voltage gain (AV) to boost the sensing voltage difference, making the sensing voltage difference of the proposed amplifier be 1 + |AV| times that of a conventional latch-type sense amplifier. And the pre-sensing operation performs in parallel with boosting to suppress the sensing noise, without additional time and area consumption. By offset calibration and voltage difference boosting techniques, the proposed design has suppressed the sensing noise and enhanced the sensing margin. All designs are implemented on SMIC 40-nm technology, operating at a supply voltage of 1.05 V or less. The proposed sense amplifier has reduced the standard deviation of the decision threshold voltage to 0.62× and improved the sensing yield by 17.96%. In addition, the boosted sensing voltage difference speeds up the sensing stage, compensating for the pre-sensing time by 36%. Keeping the same number of transistors as the prior offset mismatch calibration sense amplifier, the proposed sense amplifier with improved sensing margin is suitable for low-voltage and high-density DRAM.

Improved Operation of the Step-Up Converter with Large Voltage Gain and Low Voltage on Capacitors

This work proposes an improvement for a recently proposed converter. The discussed converter is the so-called low-voltage in capacitors (LVC). It offers a larger voltage gain compared to the standard step-up or boost converter while operating with a relatively low voltage in their capacitors (lower than the voltage at the output port). The improvement consists of a modification in the pulse width modulation (PWM) scheme. The new modulation scheme allows for a reduction in the voltage ripple at the output port, which means an improvement in the power quality. The LVC converter contains two transistors, but it was proposed to operate with a single switching signal. The new PWM scheme is based on two switching signals with the same duty cycle (same waveform and same average time in high) but 180° of phase shift among them. The PWM scheme significantly affects the voltage ripple at the converter’s output port. The voltage ripple reduction at the converter’s output port is achieved without increasing the transistor switching frequency and without modifying the circuit parameters (capacitance in capacitors or inductance in inductors). The article starts by introducing the converter. Then, it presents its mathematical model, including the calculation of the voltage ripple at its output port. The experimental results performed on the LCV in both the former and the proposed operation prove the reduction in the voltage ripple, and the comparison also includes the traditional boost converter.

A soft switched high step‐up DC‐DC converter based on VMC and coupled inductor for photovoltaic energy applications

AbstractIn this paper a new topology of non‐isolated high step‐up DC‐DC is proposed for renewable applications like photovoltaic (PV) power generation. This converter is designed based on coupled inductor and VMC techniques. The main benefits of the presented topology are: (1) Continues input current with low ripple, (2) low voltage stress across semiconductors, (3) soft switching of diodes (ZVS and ZCS), (4) high voltage gain with low duty cycle, (5) low volume and cost, and (6) high power efficiency. To obtain a high output voltage, the secondary side of the coupled inductor is integrated with VMC, resulting in a large voltage gain with low duty cycles and reduced conduction loss of power switches. Additionally, diodes' zero voltage switching (ZVS) and zero current switching (ZCS) improve the efficiency of the proposed converter. The used VMCs act as a voltage clamp, and the peak voltages across power switches are reduced. The presented converter's operational modes, steady‐state, and efficiency analysis are discussed. Additionally, to indicate the performance of the suggested structure, a 200 W prototype with Vin = 33 V and Vo = 403 V voltage conversion is built, and the experimental results are presented. The experimental efficiency at Po = 200 W is measured 95.29%. Also, efficiency is measured more than 95 % for Po = 20 W to 200 W.

Numerical Optimization of the Capacitors Selection in the MSBA Converter to Reduce the Output Voltage Ripple

DC–DC power electronics converters are widely used in many applications, such as renewable energy systems. The multistage-stacked boost architecture (MSBA) converter is a large voltage gain converter whose PWM scheme may reduce a percentage of the output voltage ripple, taking advantage of the symmetry of the voltage signals in capacitors (they are triangular waveforms) to have a symmetry cancelation. The switching ripple is unavoidable; the correct selection of components can reduce it, but this may result in a large amount of stored energy (larger size). The selection of capacitors influences the output voltage ripple magnitude. This article proposes a design methodology that combines a recently introduced PWM scheme with a numerical optimization method to choose the capacitors for the MSBA converter. The objective is to minimize the output voltage ripple by choosing two capacitors simultaneously while ensuring the constraint of a certain (maximum) amount of stored energy in capacitors is not overpassed. The internal optimization was performed with the differential evolution algorithm. The results demonstrate that the proposed method that includes numerical optimization allows having a very low output voltage ripple with the same stored energy in capacitors compared to the traditional converter. In a design exercise, up to 60% reduction was observed in the output voltage ripple with the same stored energy in capacitors.

DC‐DC parallel legs linked high gain converter for microgrid applications

AbstractFor microgrid operations, this article suggests a DC‐DC Parallel Legs Linked High Gain Converter. To realize high voltage gain, the recommended converter is transformer‐free and developed with n‐parallel legs. One active switch, one capacitor, one inductor, and one diode make up each leg of the boost converter. The operating principle, characteristic waveforms, and steady‐state study are provided for continuous and discontinuous conduction modes. High voltage gain, low voltage and low current stress on switches, compact size inductors, and low voltage capacitors are the important features of the recommended converter. The suggested converter achieves a large voltage gain without the demand of high‐frequency transformers or voltage multiplier stages. Furthermore, it works on two separate duty cycles, allowing for a wide variety of duty cycle functioning. The suggested converter is compared to a newly discussed converter, and the fundamentals of reactive component design and semiconductor device selection are discussed. The experimental findings are shown, demonstrating that the suggested converter's theoretical analysis and functioning are correct.

A Step-Up Converter with Large Voltage Gain and Low Voltage Rating on Capacitors

Step-up converters are widely used in many applications, such as renewable energy generation with photovoltaic panels and fuel cell stacks. In many cases, the required voltage gain is larger for those applications than a traditional boost converter can achieve. Several large-voltage gain converters have been recently studied. This paper introduces a converter topology in which the voltage gain is larger than a traditional boost converter. The main advantages of the proposed topology are: (i) it provides a large voltage gain without the use of an extreme duty cycle; (ii) its capacitors require a smaller voltage to be sustained compared with other, similar state-of-the-art converters; (iii) the voltage among the ground input and output is not pulsating; and (iv) it can be synthesized with commercial, off-the-shelf half-bridge packed transistors. The proposed converter can be employed in different applications, such as distributed generation and microgrids. This paper presents the steady-state analysis of the proposed converter in the continuous conduction mode, a short comparison with similar topologies, and their voltage on capacitors. Computer-based simulation results are provided to verify the principle of the proposed converter in different operating conditions.

An Improved Quasi-Z-Source Boost DC-DC Converter Using Single-Stage Switched-Inductor Boosting Technique

A modified single-stage Quasi-Z-Source (QZS) boost DC-DC converter using a single MOSFET switch with a single-stage switched-inductor (SI) network is proposed in this paper. The DC-DC converter proposed in this study provides an extra voltage gain compared to the traditional QZS DC-DC converter. An additional capacitor and diode circuit are added to the existing QZS converter to decrease the voltage stress on the MOSFET switch. Therefore, compared to the traditional QZS boost converter, the proposed Modified QZS (MQZS) converter provides large voltage gain under a low duty ratio, less voltage stress, and continuous input current. Moreover, the reliability and the conversion efficiency can be increased. The derivation of the proposed MQZS converter and its operation, selection of parameters, and comparison with another similar converter are discussed in this paper. Lastly, the simulation and experimental results are illustrated to prove the notional deliberations of the proposed MQZS converter.

Fuel-cell power conversion system based on double dual topologies

This article describes (and demonstrates through experiments) the feasible implementation of a power conversion system designed for a Fuel Cell (FC) application in renewable energy generation. The system is designed to be powered by an FC stack, which output is a low (in amplitude) non-regulated dc voltage, with a relatively wide range of variation. The system must boost the voltage from the power source to an internal 200 V dc bus, while the final output voltage (after the inversion) must be provided at a level of 120 V ac. The main feature of the described system is that it is based on double-dual converters, a family of converters with several advantages such as automatic power balance and large voltage gain; this leads to a good performance and power quality. The system is based on a double dual boost converter to increase and regulate the dc-voltage, and a double dual buck converter, to invert the dc-voltage and provide an ac-voltage as output. The article shows the system's feasibility through theoretical analysis and provides experimental results with an FC stack. Experimental results are provided to demonstrate the feasibility of the proposed system.

Implementation of non-isolated three-port converter through augmented time response

<p><span lang="EN-US">The work is concerning a multi-port dc-dc converter with improved time response and steady state output. Here the converter carries bare amount of switches for managing the power with mono inductance. The inductance and along with that the switched capacitance are pre owned to bring large voltage gain. This paper put forwarded an appropriate controller for the closed loop monitored high-gain converter with three ports. Higher is that the conversion rate. This converter is also a good interface between DC-source and load that aims to progressing time response with FLC and PI controller in the closed loop system. The converter with the PI controller and FLC is look over and the fast responses are compared with time domain specifications. The simulation outcome indicates that the FLC based converter brings most excellent time domain response.</span></p>

A Novel Nonisolated Buck–Boost Converter With Continuous Input Current and Semiquadratic Voltage Gain

A buck–boost dc–dc converter with semi-quadratic voltage gain is introduced in this article. The proposed converter benefits from continuous input current and common ground characteristic between input–output voltage ports. Due to low ripple input current, the proposed converter is a proper choice for carbon-free power sources such as photovoltaic (PV). Unlike the traditional buck–boost converter, the presented converter offers positive output voltage and large voltage gain without using an extreme duty cycle. In addition, the voltage stresses across the power switches of the proposed converter are very low compared with the output voltage. Hence, power switches with low on-resistance are used in practical implementation, which leads to power loss reduction and efficiency improvement. The performance principles, dc analysis, modeling process, and power loss analysis of the proposed converter are fully described. Finally, a laboratory prototype is implemented so as to evaluate the previously mentioned features of the proposed converter.

Design and Analysis of 2N4416 n channel JFET Single Stage Amplifier for large band width and low Voltage Gain

A bipolar junction transistor (BJT) is a current-controlled device, while a field-effect transistor (FET), is a voltage-controlled device, the bipolar transistor has two principal disadvantages. First, it has low input impedance because of the forward-biased emitter junction. Secondly, it has a considerable noise level. The field-effect transistor (FET) has a large input impedance which may be more than 100 megaohms, the FET is generally much less noisy than the ordinary or bipolar transistor. In this paper 2N4416 n channel JFET single-stage amplifier was designed, in order to analyze the circuit, important terms and main parameters were determined, the frequency response and bandwidth of the amplifier were also determined and discussed graphically using Multisim 14.2 simulator, the results characterized amplifier with large bandwidth and low voltage gain.

A new interleaved ultra‐large gain converter for sustainable energy systems

By inserting the secondary windings of the coupled inductors in series with the primary of the built-in transformer at the middle branch, a new concept is introduced for achieving ultra large voltage gain. The secondary and tertiary windings of the built-in transformer are inserted in the voltage multiplier cell. This configuration not only extends the voltage gain and minimises the voltage stress across power MOSFETs, but also gives a more flexibility to increase the voltage gain by the turns ratios of the built-in transformer and coupled inductors. Hence, high duty cycle is avoided and low voltage switches can be adopted which reduces the conduction losses. Also, the regenerative diode in each of the phases is connected to the other phase to improve equal current sharing performance. The energy of the leakage inductances is recycled by passive clamps and the high voltage spikes are avoided. Meanwhile, due to the leakage inductances of the magnetic means, the zero current switching of semiconductor devices is provided and the reverse recovery problem is alleviated. Finally, a 600 W prototype with 28–400 V voltage conversion and 97% conversion efficiency is built to demonstrate the performance of the converter.

Design of High-Efficiency Matching Networks for Capacitive Wireless Power Transfer Systems

Matching networks are an efficient means of providing large voltage or current gain and reactive compensation in high-frequency wireless power transfer (WPT) systems. This article introduces an analytical optimization approach for the design of L-section matching networks in capacitive WPT systems, which maximizes the network efficiency while achieving the required overall gain and compensation. The proposed approach identifies the optimal number of matching network stages and the optimal distribution of gains and compensations among these stages. Compared with the conventional approach to designing matching networks for capacitive WPT systems, the proposed approach results in higher and flatter efficiency for a wide range of air-gap voltages. The proposed approach also offers a better tradeoff between efficiency and power transfer density while meeting electric field safety requirements. The efficiency predictions of the proposed design approach are experimentally validated using three 6.78-MHz 100-W prototype capacitive WPT systems: one with single-stage matching networks, one with two-stage matching networks, and another with three-stage matching networks. The measured matching network efficiencies of the prototype systems are in close agreement with the theoretical predictions. The prototype system with two-stage matching networks is also compared with a prototype system designed using the conventional approach and is shown to achieve significantly higher efficiency.

High Gain Boost Converter with Reduced Voltage in Capacitors for Fuel-Cells Energy Generation Systems

This work presents a power-electronics based system for renewable energy applications, the system is driven with an only one switch quadratic type boost converter, the discussed converter is based on a stack of switching stages which provide a large voltage gain, a desirable feature for fuel cell generation systems, the converters gain function is the quadratic boost-type converters; furthermore, the topology can be extended. The major benefit of the topology is that there is not a capacitor that sustains the entire output voltage, in contrast to other similar topologies in which there is a capacitor rated to the output port voltage, there is no high voltage capacitor in this system. Experimental verification is presented to confirm the system principles; experiments included a fuel cell emulator that was built and used for the experiments.

A native oxide high-κ gate dielectric for two-dimensional electronics

Silicon-based transistors are approaching their physical limits and thus new high-mobility semiconductors are sought to replace silicon in the microelectronics industry. Both bulk materials (such as silicon-germanium and III–V semiconductors) and low-dimensional nanomaterials (such as one-dimensional carbon nanotubes and two-dimensional transition metal dichalcogenides) have been explored, but, unlike silicon, which uses silicon dioxide (SiO2) as its gate dielectric, these materials suffer from the absence of a high-quality native oxide as a dielectric counterpart. This can lead to compatibility problems in practical devices. Here, we show that an atomically thin gate dielectric of bismuth selenite (Bi2SeO5) can be conformally formed via layer-by-layer oxidization of an underlying high-mobility two-dimensional semiconductor, Bi2O2Se. Using this native oxide dielectric, high-performance Bi2O2Se field-effect transistors can be created, as well as inverter circuits that exhibit a large voltage gain (as high as 150). The high dielectric constant (~21) of Bi2SeO5 allows its equivalent oxide thickness to be reduced to 0.9 nm while maintaining a gate leakage lower than thermal SiO2. The Bi2SeO5 can also be selectively etched away by a wet chemical method that leaves the mobility of the underlying Bi2O2Se semiconductor almost unchanged.

Switching Enhancement via a Back-Channel Phase-Controlling Layer for p-Type Copper Oxide Thin-Film Transistors.

P-type copper oxide (CuxO) thin-film transistors (TFTs) with enhanced switching characteristics were fabricated by introducing a sputter-processed capping layer capable of controlling the back-channel phase (labeled as phase-controlling layer, PCL). By optimizing the processing conditions (the deposition power and postdeposition annealing parameters), the switching characteristics of the TFTs achieved a subthreshold swing of 0.11 V dec-1, an on/off current ratio (Ion/Ioff) of 2.81 × 108, and a field-effect mobility (μFET) of 0.75 cm2 V-1 s-1, a considerable enhancement in performance compared to that of CuxO TFTs without the PCL. Through optical/electrical analyses and technology computer-aided design simulations, we determined that the performance improvements were because of the CuxO back-channel phase reconstruction through PCL deposition and subsequent annealing. The two factors that occurred during the process, sputtering damage and heat treatment, played key roles in creating the phase reconstruction by inducing a local phase transition that sharply reduced the off-current via controlling back-channel hole conduction. As a sample application, we fabricated a complementary metal oxide semiconductor inverter based on our optimized CuxO TFT and an InGaZnO TFT that demonstrated a large inverter voltage gain of >14. The proposed approach opens up advancements in low-power circuit design by expanding the utilization range of oxide TFTs.

Regenerative switched‐inductor/capacitor type DC–DC converter with large voltage gain for PV applications

In grid-connected PV applications, the presence of a transformer not only increases the cost, size and weight, but also decreases the whole system efficiency, especially, under poor irradiation conditions. To eliminate the transformer and to meet DC link voltage, a regenerative switched-inductor/capacitor type DC–DC converter with large voltage gain is proposed in this study. In traditional boost type and derived converters, the voltage gain ratio is limited due to voltage stress on the semiconductor devices and low efficiency because of more components count and large duty cycle operation. The proposed converter recycles the energy in lossless passive components and increases the step-up voltage gain, which improves the efficiency. In addition, the converter possesses fewer ripples and smooth continuous current, which reduces the power loss, elongates lifespan of the input source and restricts electromagnetic interference issues. This study presents detailed operating waveforms, modes of operation and performance characteristics of the proposed converter. In order to validate the operation, 500 W experimental prototype is developed and verified with measured results. The proposed converter yields the peak efficiency of 95.20% for the output power of 440 W.

Combined zero degree structure beam dynamics and applications

The combined zero degree structure (KONUS) is a quasiperiodic structure. It was developed for the low-energy part of multigap drift tube linacs with H-type cavities. Their rf efficiency depends very much on a low electrical capacity of the drift tube structure, while in E-type structures like the Alvarez-DTL this is a minor effect. Therefore, instead of having quadrupole singlets integrated in voluminous drift tubes, KONUS allows one to develop a separated function drift tube linac (DTL) with a large voltage gain between two lenses. Very low beam injection energies can be realized, as the drift tube lengths can range down to around 10 mm. One KONUS period consists of a triplet lens, a rebuncher with a few gaps at a synchronous phase around $\ensuremath{-}35\ifmmode^\circ\else\textdegree\fi{}$, and the main multigap acceleration designed for a hypothetical zero degree synchronous particle. The longitudinal beam dynamics along this main acceleration section and the layout of the quadrupole triplet channel are explained in detail. Two examples for pulsed high current proton and heavy ion acceleration are included.