Output Voltage Polarity Research Articles

Advancing Renewable Energy: A Quadratic High-Efficiency High Gain Step-Up DC/DC Converter

Presenting a new high-gain converter that incorporates a coupled inductor, this paper offers a range of advantages over existing designs. The circuit features a simple structure with two cascade semi-stages, two power switches operating in sync, and a coupled inductor. It provides an extensive output voltage range, ensures continuous input current with minimal ripple, maintains positive output voltage polarity, and follows a standard ground configuration. These features make it well-suited for various applications, particularly in photovoltaic systems. Additionally, the voltage stress across each power switch is significantly lower than that of other boost converters, allowing for the selection of power MOSFETs with reduced drain-source ON resistance to ensure high efficiency. This research presents comprehensive assessments of the steady-state and stress conditions as well as thorough comparisons with other similar converters operating in continuous conduction mode. Theoretical advantages of the proposed circuit design are further reinforced by experimental results obtained from a 200-W step-up 25–370 V arrangement.

PV-based DC-DC buck-boost converter for LED driver

PV-based power generation is implemented in many places due to the exhaustion of carbon-based fuels and ecological challenges. The solar panels for electric power generation along with the battery for storing the extra power will help society during the future demand. This paper analyzes a tri-port converter and designs it for buck-boost operation using inductors and switches in the circuit. The voltage converter is designed to have electric Energy transfer from solar panel to LED lamp, solar panel to battery and battery to LED lamp. The voltage ratio of the proposed buck-boost voltage regulator is designed to be more as compared with the conventional buck-boost converter. Also, the proposed buck-boost Voltage regulator output voltage polarity is found to be the same as compared to the input voltage. The working battery is developed to have a bi-directional power flow to deliver power to the LED lamp and to store power from the solar panel. The switches are operated alternatively and make the mode of operation strategy simple. The design of the converter stability analysis of the system using a bode plot is done. The experimental results acquired from the prototype validate the design of the converter.

3D‐Printed Stacked Ionic Assemblies for Iontronic Touch Sensors

AbstractSensing is the process of detecting and monitoring any physico‐chemical environmental parameters. Herein, new self‐powered iontronic sensors, which utilize touch‐induced ionic charge separation in ionically conductive hydrogels, are introduced for potential use in object mapping, recognition, and localization. This is accomplished using high‐resolution stereolithography (SLA) 3D printing of stacked ionic assemblies consisting of discrete compartments having different ion transport properties. The latter assemblies readily allow programming the output voltage magnitude and polarity by means of variations in ion type, charge density, and cross‐linking density within the iontronic device. Voltages of up to 70 mV are generated on application of compressive strains of as much as 50% (≈22.5 kPa), with the magnitude directly proportional to stress, and the polarity dependent on the sign of the mobile ion. As a proof‐of‐concept demonstration, the resulting touch sensors are integrated on the fingertip to enable the tactile feedback, mimicking the tactile perception of objects for recognition applications. In addition, it is proposed that streaming potential is the underlying mechanism behind the iontronic touch sensors. The electromechanical response is therein consistent with a streaming potential model.

A single-input extended multilevel inverter based on switched-capacitor with reduced number of devices

The existing multilevel inverter (MLI) has problems such as a large number of devices, a complex structure, and a large voltage stress of the semiconductor. These shortcomings are not conducive to the modularization, high efficiency and miniaturization of the inverter. Therefore, a topology of extended switched capacitor multilevel inverter utilizing single power supply is proposed. In which, the capacitor is used as a virtual power supply, through the switching control strategy, capacitors and the power supply are reasonably combined, then a multilevel output voltage can be acquired. The proposed topology mainly has the following advantages. Firstly, it can be expanded to further increase the number of output levels. Secondly, the structure of the basic switched capacitor circuit used in the topology is simple, which can reduce the number of devices when the output is the same. Thirdly, the terminal H-bridge for output voltage polarity conversion can be eliminated in the proposed topology, which is beneficial to reduce the total standing voltage and peak inverse voltage. Therefore, an opportunity for the application of the inverter in medium and high voltage is provided. Additionally, the inherent capacitor voltage self-balancing capability of the proposed topology can eliminate the additional balancing control algorithms, therefore, the modulation strategy is simplified. Finally, the correctness and effectiveness of the topology are verified by the extensive simulation and experimental results carried out on the 13-level inverter.

Circuit Configuration of a Reduced Count Modular Multi-Level Inverter

ABSTRACT A novel topology of the modular multilevel inverter with the ability to boost the input voltage is proposed in this work. The proposed single-source structure requires neither any external controller nor transformers to balance the voltages of the capacitors. In addition, the output voltage polarity of the inverter is generated inherently with a low switching frequency, making it suitable for both residential and industrial applications. The Nearest Level Modulation (NLM) is applied to control the operation of the inverter. The detailed comparative analysis of the proposed inverter with other inverters indicates that the proposed structure can produce similar voltage levels with a fewer number of elements and less voltage stresses. Moreover, to verify the performance of the proposed converter, a single-phase 13-level prototype was implemented in the laboratory environment and the test results were compared to the simulation ones. The advantages of low harmonic contents with Total Harmonic Distortion (THD) of 6.5% and 92.69% efficiency make the proposed inverter appropriate for applications with a limited number of low voltage sources.

Implementation and design of an interleaved Cuk converter with selective input current ripple elimination capability

SummaryNowadays, buck–boost DC–DC converters are widely used in numerous power devices. However, to have a suitable buck–boost DC–DC converter, reducing the input current ripple seems to be necessary. Also, having a lower current ripple at the converter output allows using low‐cost, long‐life ceramic capacitors instead of electrolytic capacitors. The presented buck–boost converter is made by interleaving two Cuk converters with positive and negative output voltage polarity, which provides the chance to eliminate the input current ripple at the selective duty cycle. The selective duty ratio can be determined by designing the inductors amounts at the input side of both converters. Though a new combination for the buck–boost converter is presented, which has zero input current ripple and low output current ripple which is obtained by output inductors. The converter maximum voltage gain is 2D/1‐D and has easy control. In conclusion, a prototype model with 100‐W output power is implemented, and the theoretical analysis and laboratory results are compared and validated.

Interleaved Modulation Scheme With Optimized Phase Shifting for Double-Switch Buck-Boost Converter

Owing to low voltage stresses, wide range of input voltage and the same polarity of output voltage and input voltage, double-switch buck-boost converter (DSBBC) is a popular choice to achieve dc/dc conversion in photovoltaic generations (PV), power factor correction (PFC), portable devices and so on. Combined control (CC) makes DSBBC operate efficiently, but large ripples of output voltage are unavoidable during mode transition. With two equal duties, interleaved modulation (IM) makes the inductor ripple current decrease remarkably compared with synchronous modulation (SM) while inductor average current is still high. By introducing duty offset, inductor average current declines and efficiency is enhanced obviously under interleaved modulation with duty cycle offset (IMDO). However, with 180-degree phase-shifted angle, the ripple current is not low enough in some cases. Thus, to make further improvement on ripple current, an interleaved modulation scheme with optimized phase shifting (IMOPS) is proposed for DSBBC in this paper. Current features, optimal phase-shifted angle (OPSA) and operating region under IMOPS are described meticulously. Besides, theoretical and quantitative comparisons of different modulation schemes are presented, including inductor average current, inductor ripple current and ratio of direct power transfer (DPT). Based on a 150W prototype, the feasibility and effectiveness of IMOPS are demonstrated by experimental results.

General Method for Synthesizing High Gain Step-Up DC–DC Converters Based on Differential Connections

This article introduces a powerful methodology to synthesize high gain step-up dc–dc converters from differential connections of two converters. The two selected converters may be either equal or different, and they can use different kinds of gain cells. Both only have to present a common reference between the input and output voltages and the same output voltage polarity. The proposed differential connection supplies high step-up converters and mainly the method can be applied to synthesize different topologies from different well-known converters. Besides the derivation and analysis of some converters in continuous conduction mode, the article also discusses the power processing, reduction of components, addition of gain cells to further increase the gain, different kinds of modulations, and addresses a different point of view for some topologies previously published in literature. The proposed methodology is verified through thirteen prototypes derived from basic converters considering input voltage of 20 V, duty cycle of 0.75, switching frequency of 50 kHz and rated power of 100 W. Moreover, three new ultrahigh gain dc–dc converters are still derived from the insertion of gain cells in the differential converters herein proposed. These three converters are experimentally evaluated under input voltages of 20 and 30 V, rated power of 200 W and, switching frequency of 50 kHz, providing static gains from 15 up to 30, and peak efficiency of 96.78%.

Regulating the output performance of triboelectric nanogenerator by using P(VDF-TrFE) Langmuir monolayers

The performance improvement of triboelectric nanogenerator (TENG) has always been an important issue. Herein, we report a surface modification method based on P(VDF-TrFE) deposited Langmuir monolayer to regulate the output performance of TENG. For the TENG using ITO electrode and polyethylene terephthalate (PET) film as the tribo-materials, the polarity of output voltage can be reversed by depositing a P(VDF-TrFE) monolayer on the surface of ITO. By using Kelvin probe measurement, we found that the dipole moment of monolayer can increase effective work function of ITO and the homogeneity of the monolayer in micro scale can also influence the performance of TENG. Through energy band diagram, the physical mechanism of charge transfer during contact electrification and the contribution of dipole monolayer to the electrification process are systematically illustrated. Moreover, the monolayer deposited on ITO electrode can capture electrostatic charges during corona polarization, which can further improve the output performance of TENG for more than 15 times. The surface modification methods introduced here can offer a simple but effective way to modulate the output performance of TENG, and our related physical analysis also helps to clarify the mechanism of contact electrification.

Advanced Single-Phase Nine-Level Converter for the Integration of Multiterminal DC Supplies

This paper presents a new symmetrical single-phase nine-level dc–ac converter for the applications of distributed generation systems. The proposed multilevel inverter (MLI) utilizes four independent dc sources to generate the nine output voltage levels considering a reduced number of switching devices. The proposed inverter consists of main and auxiliary circuits. The main circuit is a single H-bridge circuit, which is responsible for output voltage polarity. The auxiliary circuit consists of a special combination of switching devices, which are used to synthesize the multilevel output voltage. The merits of the proposed MLI are: increased output voltage levels at reduced number of switching devices, low switching loss, low total harmonic distortion, low dv/dt stress on the switches, and hence, low ratings of the switching devices, and low cost. The effectiveness of the proposed MLI and its pulsewidth modulation switching pattern has been verified experimentally by using a laboratory prototype controlled by DSPACE-1103.

Reduction of the Output Noise Level of Reference Voltage Sources

The development of digital technologies that are widely used in industry and agriculture imposes increased requirements on the reference voltage sources for a variety of parameters, each of which is important. However, further enhancement of the resolution of analog–digital and digital–analog converters and, hence, the digital signal processing as a whole, is impossible without improving such the noise level quality index of reference voltage sources. This work describes a method and circuit design for constructing a low-noise source of stable dc voltage on the basis of typical microelectronic circuits of voltage stabilizers. The developed circuit design provides a reduction in the output noise level of the reference voltage sources made based on such microelectronic circuits of voltage stabilizers up to the level of intrinsic noise of the operational amplifiers used in the developed device. The developed source of stable dc voltage is characterized by inversion of the output voltage polarity relative to the output voltage polarity of the microelectronic circuit of the voltage stabilizer that is used.

Efficient Performance Technical Selection of Positive Buck-Boost Converter

The necessity for stable DC voltage in both removable and non-removable systems has been considerably desired recently. These systems have to be implemented efficiently in order to be responding rapidly based voltage variations. Under this act, the efficient power can extend the lifetime of the employed batteries in such systems. The presented efficiency can be realized with respect to buck and boost components that were implemented to generate what is called positive Buck-Boost converter circuits. The main functions of the positive Buck-Boost converter are identified by announcing the unchanged situation of output voltage polarity and indicating the level of the voltage rationally between the input and the output. It is worth mention, the positive Buck-Boost converter circuit was simulated based Proteus software, and the hardware components were connected in reality. Finally, the microcontroller type that employed in the proposed system is PIC_16F877A, which realizes the input voltage sensitively to generate Pulse Width Modulation (PWM) signals in order to feed the employed MOSFET element.

Analysis of Controlled Single-phase Full-Wave Rectifier with RL Load

Diodes are popularly used in rectifiers, which convert an ac signal into a unidirectional signal. They produce a fixed output voltage only. However, controlled switches such as thyristors are used to vary the output voltage of a converter by adjusting the delay or firing angle ? of the thyristors. Phase-controlled converters are simple, efficient and less expensive. There are both single-phase and three-phase converters depending on the input supply. We also have half-wave and full-wave converters. The half-wave converter has only one polarity of output voltage and current, while for the full converter, the polarity of the output voltage can be either positive or negative. The purpose of this paper is to investigate the operation of the Single-phase full-wave rectifier. Load current for the controlled full-wave rectifier with R-L load can be either discontinuous or continuous. The paper shows how the rectifier transits from discontinuous current operation to continuous current operation.

Analysis of Controlled Single-phase Full-Wave Rectifier with RL Load

Diodes are popularly used in rectifiers, which convert an ac signal into a unidirectional signal. They produce a fixed output voltage only. However, controlled switches such as thyristors are used to vary the output voltage of a converter by adjusting the delay or firing angle α of the thyristors. Phase-controlled converters are simple, efficient and less expensive. There are both single-phase and three-phase converters depending on the input supply. We also have half-wave and full-wave converters. The half-wave converter has only one polarity of output voltage and current, while for the full converter, the polarity of the output voltage can be either positive or negative. The purpose of this paper is to investigate the operation of the Single-phase full-wave rectifier. Load current for the controlled full-wave rectifier with R-L load can be either discontinuous or continuous. The paper shows how the rectifier transits from discontinuous current operation to continuous current operation.

New Switching Strategy for Single-Mode Operation of a Single-Stage Buck–Boost Inverter

Generally, single-stage buck–boost inverters consist of distinct circuits operating individually in buck/boost or positive/negative modes, the latter definitely leading to crossover distortion in the output current. This paper proposes a switching strategy that changes the bimodal operation of a single-stage buck–boost topology to a single-mode inverter. This is due to the consequent voltage gain that ensures that the output voltage polarity, apart from its magnitude, is an exclusive function of the duty ratio. Operational principle and salient hardware design are explained with the help of equivalent circuits. Details about the dynamic model are presented, based on which controller design is carried out for both stand-alone and grid-connected operation. Experimental results obtained from a 300-W, 110-V laboratory prototype are presented to validate the performance of the proposed switching strategy.

Level Reduction of Output Noise of Reference Voltage Sources

Abstract Technologies for processing of digital signals find broad application in all spheres of the human activity, including agriculture. Further perfecting of these technologies is related to increasing of resolving power in analogue-to-digital and digital-to-analogue converters, requiring the improvement of quality indicator of the reference voltage sources such as noise level. This paper presents the possibilities for level reduction of output noise of the reference voltage sources. Circuit solutions of the single-stage and twostage, unipolar and bipolar low-noise sources of stable voltage of direct current produced on the basis of standard integral chips of voltage stabilizers are observed. The proposed circuit solutions provide reduction of output noise level of the reference voltage sources to the level of intrinsic noise of the operational amplifiers, which are part of the developed devices. It should be emphasized that single-stage unipolar low-noise sources of stable voltage of direct current are characteristic by the inversion of output voltage polarity that takes place in accordance with the polarity of output voltage of voltage stabilizer integral chip.

Sensor less Control of BLDC Motor using Fuzzy logic controller for Solar power Generation

Brushless dc (BLDC) motors are electronic controlled and have the rotor position for commutating the stator winding current. This paper presents the BLDC motor sensor less speed control system with fuzzy logic implementation. The sensor less method based on the back EMF sensing and the rotor position detection with a high starting torque is suggested. This Paper presents the efficient power generation of Photovoltaic System and deal with the sensor less control of BLDC motor. The controller design of a solar module has established for maximum power. It consists of a solar panel and boost converter for maximum power generations. This boost converter can be operating step up mode with less passive component counts and non-inverted output voltage polarity. The sensor less control of BLDC motor based on fuzzy control and a potential start-up method with a high starting torque are indicated. The rotor position is adjusted at standstill for high starting torque. The stator current can be changed by modulating the pulse width of switching devices during alignment. The controller performance of solar module and corresponding simulation results are verified by using MATLAB/Simulink environment.

A New Transformerless Buck–Boost Converter With Positive Output Voltage

A new transformerless buck–boost converter with simple structure is proposed in this study. Compared with the traditional buck–boost converter, the proposed buck–boost converter’s voltage gain is squared times of the former’s and its output voltage polarity is positive. These advantages enable it to work in a wider range of positive output. The two power switches of the proposed buck–boost converter operate synchronously. In the continuous conduction mode (CCM), two inductors are magnetized and two capacitors are discharged during the switch-on period, while two inductors are demagnetized and two capacitors are charged during the switch-off period. The operating principles, the steady-state analyses, and the small-signal model for the proposed buck–boost converter operating in CCM are presented in detail. The power electronics simulator (PSIM) and the circuit experiments are provided to validate the effectiveness of the proposed buck–boost converter.

Improvement of Triboelectric Efficiency using SnO2 Friction Layer for Triboelectric Generator

The triboelectric property of a material is important to improve an efficiency of triboelectric generator (TEG) in energy harvesting from an ambient energy. In this study, we have studied the TEG property of a semiconducting which has yet to be explored so far. As a counter triboelectric material, PET and glass are used. Vertical contact mode is utilized to evaluate the TEG efficiency. thin film is deposited by atomic layer deposition on bare Si wafer for various thicknesses from 5.2 nm to 34.6 nm, where the TEG output is increased from 13.9V to 73.5V. Triboelectric series are determined by comparing the polarity of output voltage of 2 samples among , PET, and glass. In conclusion, , as an intrinsic n-type material, has the most strong tendency to be positive side to lose the electron and PET has the most strong tendency to be negative side to get the electron, and glass to be between them. Therefore, the -PET combination shows the highest TEG efficiency.

High step‐up Z‐source DC–DC converter with coupled inductors and switched capacitor cell

Z-source converter has several advantages such as high-voltage gain, clamped switch voltage and positive output voltage polarity. This study presents a new non-isolated high step-up DC–DC converter which is derived from Z-source converter and provides higher-voltage gain compared with its conventional counterpart. Owing to its high-voltage conversion ratio, the proposed converter is a proper choice for photovoltaic applications. Furthermore, reverse-recovery problems caused by the output diode are reduced in the proposed converter which reduces the switching losses. In addition, the leakage energy is recycled so the conversion efficiency is improved. Analysis and operating principles of the proposed converter are discussed and design guidelines are presented. Moreover, the effect of non-ideal elements on the proposed converter performance is analysed. A 100 W laboratory prototype to convert 20–300 V is implemented and experimental results are presented to verify theoretical analysis.