High Voltage Gain Research Articles

Optimal Power Flow in Grid Connected EV Charging System Using High Gain Sheppard-Taylor Converter

The prominence of Brushless Direct Current (BLDC) motor in operation of electric vehicles is significantly enormous in recent days as it owns beneficial factors like lower switching stress, higher voltage gain, optimum conversion efficiency and simple structure. Because of its advantageous features, it is preferred as suitable option for Electric Vehicle (EV) applications. The proposed approach concentrates on process of coupling electric vehicles like electric train with Photovoltaic (PV) and grid. The Interleaved Sheppard-Taylor converter is active in this system for improvising PV output in wider range to compensate grid voltage. A 3Φ Voltage Source Inverter (VSI) is implemented to feed converter output to electric vehicle, whereas 1Φ VSI assists in providing converter output to grid. For regulating switching behavior of inverter, Proportional Integral (PI)controller with hybrid Firefly assisted Artificial Bee Colony (FF-ABC) Algorithm is employed in this paper. The inverter, connected with grid allows current to flow in bidirectional mode to satisfy power demand of vehicle. The proposed PV fed grid tied electric car topology is compared with alternative interleaved topologies to demonstrate that suggested converter achieves excellent voltage gain and conversion efficiency. The entire system is validated in Matlab Simulink and system meets required power quality standard.

Large‐Area Deposition of Highly Crystalline F4‐Tetracyanoquinodimethane Thin Films by Molecular Step Templates

Theoretical studies have unequivocally determined the exceptional electron transport properties of the fluorinated tetracyanoquinodimethane (Fx‐TCNQ) family, presenting a promising avenue for the realization of high‐performance n‐channel organic thin‐film transistors (OTFTs). However, owing to the intrinsic low crystallinity of this class of materials, Fx‐TCNQ‐based n‐channel OTFTs have not been experimentally achieved so far. Herein, a molecular step template (MST)‐assisted method that dramatically improves the crystallinity of F4‐TCNQ thin films is reported. The MST not only lowers the nucleation barrier of F4‐TCNQ molecules along the in‐plane direction but also reduces the nucleation density. This approach facilitates the realization of compact, oriented, and highly crystalline F4‐TCNQ thin films, resulting in impressive electron mobility of up to 2.58 cm2 V−1 s−1. Notably, this achievement surpasses the electron mobility of F4‐TCNQ thin films fabricated without the MST by a factor of 107. Furthermore, the incorporation of the p‐type MST provides a novel pathway for constructing complementary inverters, showcasing a high voltage gain of 112.6 V V−1 and a substantial noise margin of 89.3% with exceptional uniformity. In this work, a general and efficient route is paved to produce high‐performance n‐channel OTFTs toward organic complementary circuits.

A novel on high voltage gain boost converter with cuckoo search optimization based MPPTController for solar PV system

Traditionally, isolated and non-isolated boost converters are used for solar photovoltaic systems (SPV). These converters have limitations such as low voltage gain, less voltage ripples, temperature dependence, high voltage stress across the switches, and being bulky in size. Besides, the solar PV system also has non-linear characteristics between I–V and P–V, and the energy yield potential is affected by partial shading phenomena. Therefore, maximum power point tracking (MPPT) is being added to the SPV system to get the maximum output power under steady and dynamic climate conditions. Although the conventional MPPT has drawbacks such as less accuracy in predicting the MPP under partial shading conditions, low tracking speed, and more ripples, Hence, the research proposes a stackable single switch boost converter (SSBC) with a Cuckoo search MPPT controller for the SPV system. The efficiency of the proposed circuit topology has been compared with conventional boost converters with various MPPTs. Subsequently, the accuracy of tracking true MPPT by CSO is compared with that of PSO and FPNA. The results show, that the CMPPT with CBC has produced more ripples, whereas the BMPPT with SSBC produces ripple-free power under steady conditions. It is also observed that SSBC with BMPPT produces more power than SSBC with TMPPT. The efficiency of SSBC with BMPPT is better than other combinations. Finally, a prototype model has been developed and verified.

A switched‐capacitor‐based active‐interleaved‐network with high voltage gain

SummaryA high voltage gain characteristic is required in fuel cell vehicles to achieve voltage matching between low voltage fuel cell and high voltage DC‐link bus. In this paper, a non‐isolated high step‐up dc‐dc converter based on switched‐capacitor (SC) and active‐interleaved‐network (AIN) is proposed. The main advantages of the converter are the high voltage gain without an extremely high duty cycle, automatic current sharing of inductors, reduced input current ripple, and lower device voltage stress when compared to the topologies with the same output voltage. Detailed descriptions of the converter including operation principle and dynamic response analysis are presented in this manuscript. To verify the correctness of the theoretical analysis and feasibility of the proposed converter, a 500 W prototype with 20 V input and 200 V output is built.

Unified control of high gain DC-DC converter for PV-battery hybrid system in a standalone and DC-microgrid applications

This paper presents power management and control of standalone PV and battery integrated hybrid system using high gain converter suitable for the DC Microgrid applications. The necessity of high gain DC-DC converter is raised due to generation of low output voltage of PV system. The attractive features of high gain converter are high voltage gain, continuous input current and suitability for integration of multiple input sources. The perturb and observe algorithm is used for tracing the maximum power point from solar and intermittency of solar is compensated by energy storage element battery. In the suggested hybrid system, the battery charging is carried out from DC bus voltage through buck converter and discharging to the load through high gain DC-DC converter. In the proposed work, Simulink model of proposed system rated for 1.2 kW PV module, 120 V, 42 Ah battery is developed using Simulink of MATLAB software and results are obtained under different operating conditions. Scaled experimental model of proposed hybrid system is implemented in laboratory environment using STM32F407VGT6 microcontroller and results are validated.

Improving Performance of Solar Array Fed BLDC Drive Using Firefly Algorithm Based High Gain Converter

The improved transient response of PID controller for improved Luo converter supplied Brushless DC (BLDC) motor using solar energy source is extensively investigated. The BLDC drive uses a hybrid PV system and battery-based power generation as a power source to assure continuous power supply to pump water regardless of solar insolation. The PV system serves as the main energy source, and the battery providing as a backup source that discharged its power only during inclement weather or at night if the photovoltaic panel is insufficient to operate the centrifugal pump. The solar panel feeds power into the battery, whenever water to the field is not required, thus there is no need for an extra power source to charge the batteries. The high output voltage gain DC-DC converter does not make any discomfit to the system performance in regards to irradiance variation, switching loss, or power loss by converter or motor side respectively. Moreover, current sensor, voltage sensor, and control circuits are completed excluded which enhance performance and the cost of the system get reduced effectively. A bidirectional charging control allows a bi-directional converter to alter the battery operation mode automatically. The overall system performance is validated using simulation and experimental setup.

A Multiport Current-Fed IIOS Dual-Half-Bridge Converter for Distributed Photovoltaic MVDC Integration System

The input-independent output-series (IIOS) dc-dc converter structure possesses the capability to achieve high voltage gain, single-stage power conversion and multiport independent control, which is suitable for distributed photovoltaic (PV) power collection system. However, if the multiport input powers are different, the output voltage of each submodule (SM) will be uneven, which might lead to power degradation and device damage. In order to address SM output voltage imbalance problem, a voltage self-balancing output-series dual-half- bridge (OSDHB) converter based on multi-winding coupled-inductor (MWCI) is developed in this paper. By multiplexing the SM secondary side switches in OSDHB, the unbalanced power between SMs can be directly transmitted to the target SM, without the requisition for transmission one by one. And all power switches possess zero-voltage switching characteristic. Therefore, the proposed IIOS-DHB features high efficiency, low cost, simple control and more adaptive to distributed PV power generation system. The topological configuration, operating principle and self-balancing performance are presented. Finally, the full-scale simulations and three submodules down-scale experiment hardware platform have been conducted to verify the theoretical analysis of the proposed IIOS-DHB.

High-Frequency Interlinking High-Voltage Gain PV Converter Modules With Embedded Power Balancing Technique for DC-Distributed System

High-Frequency Interlinking High-Voltage Gain PV Converter Modules With Embedded Power Balancing Technique for DC-Distributed System

A Stacked Symmetrical Non-Isolated High Step-Up Voltage Gain Converter with High Efficiency and Low Voltage Stress on Components

This paper introduces a cascaded symmetrical non-isolated high step-up voltage gain converter with high efficiency and low voltage stress on components combining a non-isolated buck-boost converter and voltage doubler structure. In the proposed converter, the input source is connected in series to the output load; hence, a part of the source energy is directly delivered from source to load, not through the switching branch, improving efficiency. Furthermore, the appropriately stacked voltage doubler stage not only amplifies the high step-up voltage gain ratio but also considerably diminishes the voltage stress on all semiconductor devices and capacitors. As a result, the costless low internal resistance and low voltage components can be employed for higher efficiency, higher power density, and lower cost. To demonstrate the practicality of the proposed topology, the operating principle is outlined, and the steady-state characteristics are thoroughly analyzed. Furthermore, a 360 W prototype converter has been fabricated to confirm the efficiency of the proposed converter.

Direct maximum power injection control of grid-connected PV micro-inverter systems connected to the grid

The increasing use of fossil fuels such as gas and oil has caused many environmental problems, including air pollution, depletion of underground resources, the destructive phenomenon of global warming, destruction of the ozone layer, and many other problems for the environment. Photovoltaic systems are one of the most promising solutions to overcome these problems. Due to the low voltage of solar panels and the higher controllability of photovoltaic systems against changes in sunlight intensity during the day, DC-DC power converters are required. In this project, the aim is to design and build a DC-DC converter with the ability to provide high voltage gain at a suitable efficiency for a 1-string photovoltaic system with the ability to track the maximum power point 2. The designed converter is designed and analyzed with the ability to provide a voltage gain of 5/6 at the critical operating point, a minimum efficiency of 94%, and a power of 500 watts. This converter uses classical soft switching, so the switching losses are reduced, which in turn increases the efficiency of the converter. This converter has a lower voltage stress on the switch (4/0) than the existing techniques. On the other hand, while new converters use a large number of switches and magnetic cores in the cell to provide high gain, this converter uses the least number of switches and magnetic cores to achieve high gain. Also, the passive elements of this converter, such as inductor and capacitor, are in the order of a few microhenries and farads, and therefore the size of these components is also reduced. In addition, due to the high gain provided in lower duty cycles, the efficiency of the switch is increased, and therefore cheaper switches can be used. Also, due to the reduction in the size of passive elements, the size of the magnetic core is also reduced, which in turn optimizes the converter economically.

Tunable optoelectronic response in van der Waals heterojunction transistors for artificial visual recognition

Optoelectronic synaptic transistors are advantageous in in-memory light sensing for artificial neural networks. Herein, optoelectronic synaptic junction field-effect transistors (JFETs) based on a Ga2O3/MoS2 heterojunction are fabricated. The devices exhibit robust electrical performances, including a high on/off ratio of 108, a low subthreshold swing of 69 mV dec−1, and a high output current of 3.4 μA μm−1. An inverter and a NAND gate are constructed based on the dual-gated configuration, with the inverter showing a high voltage gain of 28 and the near-ideal noise margin of 90.4%. Additionally, the devices demonstrate outstanding optoelectronic performances benefiting from the strong light–matter interactions of MoS2. Typical synaptic plasticities, including short-term plasticity, long-term plasticity, and spiking-rate-dependent plasticity, are simulated by applying the light pulses. Furthermore, metaplastic excitatory postsynaptic current, metaplastic facilitation of long-term potentiation and transition from potentiation to depression are also readily demonstrated. The artificial neural network, in which neurons are interconnected through our proposed optoelectronic synaptic transistors, achieves a high accuracy of 89.8% in recognizing handwritten digits. This work provides insight into the design of an optoelectronic synapse based on JFETs.

A zero‐input‐current‐ripple high‐voltage‐gain DC‐DC converter with integrated Y‐source network

SummaryThis paper proposes a zero‐input‐current‐ripple (ZICR) high‐voltage‐gain dc‐dc converter with an integrated Y‐source network. It achieves zero input current ripple by introducing a parallel branch of an extra inductor, a coupled winding, and a capacitor at the input port. The voltage of the added inductor is opposite to that of the coupled winding. By adding the Y‐source coupled inductor, the boost capability of the converter is improved. The unique boost circuit structure makes that one winding in the three‐winding coupling inductance is step‐down type (the turns ratio n2 < 1) while the other winding is step‐up type (the turns ratio n1 > 1). In such a case, high voltage gain can be obtained under a lower turn ratio of the coupled inductor. The inherent passive clamping circuit clamps the spike voltage noises of the main switch to a low level and improves the efficiency. All the diodes have achieved ZCS (zero current switching) turn‐off. By comparing with several new converters, the advantages of this converter are proved. Finally, a 200‐W, 48‐ to 380‐V, 50‐kHz experimental prototype is built based on the theoretical research. At the rated power, the measured efficiencies with and without ZICR are 95.2% and 95.6%, respectively.

Electrical Properties of Electrochemically Exfoliated 2D Transition Metal Dichalcogenides Transistors for Complementary Metal‐Oxide‐Semiconductor Electronics

AbstractThe unique semiconducting characteristics of 2D materials, such as transition metal dichalcogenides (TMDs), have drawn significant interest in the field of electronic devices. However, the dependence of the device performance on the electrical properties of electrochemically exfoliated TMD nanoflakes remains unclear. In this study, the intrinsic electrical properties of diverse electrochemically exfoliated TMD nanoflakes are investigated and their applications in fully solution‐processed 2D electronics are explored. The study reveals that MoSe2 and WS2 nanoflakes are suitable candidates with moderate electron concentrations of 5.7 × 1012 and 2.5 × 1012 cm−2, respectively. These moderate electron concentrations enable a low off‐state current and high on‐state current, leading to a large on–off ratio (> 106) for the fabricated transistors. Furthermore, moderate annealing can increase the mobility by one order of magnitude by reducing the contact resistance and improving charge transport. Additionally, the trap density is significantly reduced, leading to an improved stability. Finally, fully solution‐processed 2D complementary inverters with a high voltage gain of 60 are demonstrated. This study contributes to a growing understanding of the properties of 2D materials in terms of transistor performances and promotes the development of solution‐processed devices applicable in next‐generation electronics.

Soft switching high step-up three-level boost DC-DC converter with Quasi Z-source for Photovoltaic application

A three-level Boost DC-DC converter is proposed in this paper. Quasi Z-source converter acts as an auxiliary circuit to create soft switching condition for all active elements. Consequently. The converter efficiency is very high. Using a three-level structure in the proposed converter causes the maximum voltage stress across the semiconductor devices is limited to half of the output voltage. The converter has a high voltage gain and a small number of elements. The converter is analyzed with details in all operating modes. Furthermore, the experimental results are obtained to prove the converter performance based on the theoretical considerations.

High-mobility wide bandgap amorphous gallium oxide thin-film transistors for NMOS inverters

Wide bandgap gallium oxide thin-film transistor (TFT) is promising for next-generation sustainable energy-efficient power electronics. In particular, amorphous oxide channel exhibits inherent advantages on mass productions based on a low-temperature processability compatible with cost-effective large-sized glass. Here, we developed hydrogen defect termination to produce amorphous-GaOx (a-GaOx) channel for n-channel oxide-TFT and demonstrated high-mobility a-GaOx-TFT exhibiting a high saturation mobility (μsat) of ∼31 cm2 V−1 s−1, threshold voltage (Vth) of ∼3.3 V, a current on/off ratio of ∼108, and subthreshold swing value (s-value) of ∼1.17 V·dec−1. The study found that oxygen conditions during the channel fabrication process, i.e., oxygen partial pressure during the film deposition and post-thermal annealing atmospheres, were critical for the TFT performances of gallium oxide-TFTs, and subgap defects originated from low-valence Ga+ state and excess oxygen rather than oxygen vacancy had a large responsibility for the device performances. The finding explains why the development of gallium oxide-TFTs is largely behind the other oxide-TFTs. We also fabricated depletion and enhancement-mode a-GaOx-TFTs and developed a full-swing zero-VGS-load inverter with high voltage gain ∼200 and sufficient noise margins. The present study demonstrates a high potential of gallium oxide channel for low-temperature processed n-channel oxide-TFT for next-generation electronic applications.

Design and implementation of grid tied high step-up DC-DC converter with switched capacitor

In this paper, the design and implementation of a three-phase grid-connected inverter coupled with a high step-up DC-DC converter with a switched capacitor is demonstrated. In this converter two capacitors are utilized with a coupled inductor. The charging of capacitors takes place parallel and discharging in series during switch off and switch on time respectively. The energization of the coupled inductor provides the high voltage gain. The passive clamp circuit is used to recycle the leakage energy of the inductor circuit. Therefore, the switch stress is reduced. This high gain converter is given DC input of 40 V and a high voltage 538 V obtained is supplied to the grid connected inverter which uses sinusoidal pulse width modulation (SPWM), to obtain 3phase line-neutral voltage of 415 V from inverter for grid synchronization. A high voltage gain of 13 and efficiency of 96% is obtained for different load and voltage variation. The modeling and the simulation are done using physical security information management (PSIM) software and all the results are presented in this paper.

1- Dual Boost ANPC Type Inverter Topology With High Voltage Gain

1- Dual Boost ANPC Type Inverter Topology With High Voltage Gain

Unsymmetrical Dual-Input Isolated High Gain Bidirectional DC–DC Converter With Inherent Current Sharing for Light EV Applications

In hybrid Electric Vehicles (EVs), multi-input DC-DC converters with different sources of energy storage are preferred to enhance the EV market penetration. The proposed new topology is a modified SEPIC converter with integrated boost cell, capable to handle the battery and ultracapacitor with different terminal voltage. It is also having single source transition capability. This multi-input DC-DC converter provides the high voltage gain, input-output isolation and bidirectional power flow feature. The essential of regeneration in the EV is demonstrated to achieve the better energy utilization. The current sharing between the energy storage systems (battery and ultracapacitor (UC)) is inherently provided by the topological structure of the proposed converter. Hence, it eliminates inner current control loop requirement. Accordingly, cost and control complexity is minimized with improved storage utility. Therefore, the proposed converter’s functional capabilities are suitable for battery/UC based Light EV applications. The operating performance is evaluated on a 250 W hardware prototype to validate the functional capability of the proposed converter.

High-Voltage Gain Ripple-Free Resonant DC–DC Converter Using Active Voltage-Quadrupler

This paper presents a high-voltage gain ripple-free resonant DC/DC converter using an active voltage-quadrupler. By incorporating an active voltage-quadrupler at the secondary side of the transformer, the circuit achieved a very high-voltage gain. Without using extra input inductors, the inherent dual transformer plus interleaved active-clamped circuit operating with a fixed duty-ratio of 0.5 generate a ripple-free input current, which extends the lifetime of the fuel cell and shrinks the size of the input capacitive filter. This asymmetric structure of the active-clamp circuit requires an extra dead time for one of the secondary-side switches to achieve zero-voltage switching (ZVS) turn-on. After the extra dead time for one of the secondary-side switches is applied, all power components of the active voltage quadrupler cell are turned on and off with soft switching. The resonant capacitor voltages are unbalanced due to the extra dead time, but they are compensated by applying different secondary-side duty ratios. The operating principle and steady-state characteristics of the proposed converter were analyzed in detail. We built a 1-kW/700-V prototype that copes with 48-72 V inputs, and tested to verify the theoretical analysis.

A Family of DC-DC Converters Based on Y-Source Impedance Network and Boost Module

A novel family of high-gain converters based on the Y-source impedance network is proposed in this paper, providing novel solutions to high voltage gain applications. Compared with the traditional improved Y-source topology, the proposed new topologies relocate the switch from the output side to the input side, which effectively reduces the stress of the switching device, and the topology combines different boost modules, which effectively improves the boost ability. In order to show the characteristics of the proposed topologies, the operating principles and analyses are given detailed in this paper. Experimental results verify the feasibility of the proposed converters.