Good Output Characteristics Research Articles

Torque Performance Analysis of Asymmetric Magnetic Pole Permanent Magnet Synchronous Motor for New Energy Vehicles

In view of the problem of large torque ripple and poor output performance of permanent magnet synchronous motor, a new topology of asymmetric magnetic pole permanent magnet synchronous motor is proposed, and the torque ripple of this motor structure and the suppression method are analyzed. First, the equivalent magnetic circuit method and Lorentz force law are used to derive the analytical formula of torque ripple of the motor. Then, based on the analytical formula, the parameters of permanent magnet of the asymmetric magnetic pole permanent magnet synchronous motor are optimized and verified by finite element software simulation; on this basis, the method of rotor eccentricity is used to further weaken the torque ripple of the motor, and the optimal eccentricity distance is analyzed. The research shows that when the parameters of the magnetic pole of the asymmetric magnetic pole permanent magnet synchronous motor is appropriate, the harmonic content of the air gap magnetic density of the optimized motor is greatly reduced, and the motor has good output characteristics, and the torque ripple is reduced to 5.4%. Finally, the prototype is trial‐manufactured and tested. The results show that after optimization, the cogging torque of the motor is reduced, the torque output performance is improved, and the overall motor performance is improved. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.

Design of a Portable Emergency DC Power Supply

Abstract In recent years, wireless or handheld devices have become increasingly widely used, especially in areas such as environmental monitoring and the Internet of Things. However, due to environmental conditions, they cannot rely on the power grid to provide electricity, and energy supply has become a key issue that restricts the deployment and operation of such devices. This article introduces the method and principle of applying a microcontroller control system to a portable emergency DC power supply, and proposes a method for a portable emergency DC power supply with adjustable and stable output. The output voltage can be adjusted in steps of 0.1-15V. This adjustable portable emergency DC power supply not only has the advantages of small volume and low loss of switch mode power supply, but also has the advantages of small output voltage ripple and good output characteristics of linear power supply. It has certain research significance and practical value.

Constant-Voltage and Constant-Current Controls of the Inductive Power Transfer System for Electric Vehicles Based on Full-Bridge Synchronous Rectification

When an inductive power transfer (IPT) system conducts wireless charging for electric cars, the coupling coefficient between the coils is easily affected by fluctuations in the external environment. With frequent changes in the battery load impedance, it is difficult for the IPT system to achieve constant-voltage and constant-current (CVCC) controls. A CVCC control method is proposed for the IPT system that has a double-sided LCC compensation structure based on full-bridge synchronous rectification. The proposed method achieved good dynamic stability and was able to effectively switch between the output current and voltage of the system by adjusting only the duty cycle of the switch on the secondary side of the rectification bridge. As a result, the system efficiency was improved. The output characteristics of the double-sided LCC compensation structure was derived and the conduction condition with zero voltage was analyzed by using four switches through two conduction time series of the rectifier circuit. Then, the output voltage of the synchronized rectifier was derived. The hardware implementation of the full-bridge controllable rectifier was described in detail. Finally, a MATLAB/Simulink 2018a simulation model was developed and applied to an 11 kW prototype to analyze and validate the design. The results showed that the designed system had good CVCC output characteristics and could maintain constant output under certain coupling offsets. Compared with semi synchronous rectification methods, the proposed method had a higher efficiency, which was 95.6% at the rated load.

Low-frequency operation control method for medium-voltage high-capacity FC-MMC type frequency converter

The application of modular multilevel converters (MMCs) to large drive systems is subject to severe low-frequency operation restrictions. The fluctuation of capacitor voltage and the high amplitude of common mode voltage in sub-modules is a thorny problem. In this paper, a novel fly-across capacitor modular multilevel converter topology is adopted to eliminate low-frequency voltage ripples by using the fly-across capacitor as a power transfer channel between the upper and lower bridge arms of the MMC. A novel finite compensation method is proposed—instead of the traditional full compensation method—that introduces a real-time variable limiting factor to change the amplitude of the mixed injected high-frequency differential-mode voltage and high-frequency differential-mode current and reduce the amplitude of the common-mode voltage on the AC side while lowering the current stress of the power devices. Finally, a complete system simulation model is constructed, and the topology with the proposed control strategy are verified to have good output characteristics under different operating conditions; good results are achieved in suppressing the sub-module fluctuation and common-mode voltage.

Generation of Q-switched fiber laser based on ferroferric oxide in 1.55 µm region

To improve the performance of fiber lasers, a Q-switched fiber laser based on iron oxide nanomaterials was developed. The pump power was gradually increased, and the corresponding data of the Q-switched pulse frequency and spectral width were recorded. When a pump power of 170 mW was reached, the Q-switched pulse frequency of 48.45 kHz, pulse width of 2.3 μs, center wavelength of 1530.4 nm, and spectral width of 3.8 nm were observed and recorded. The Q-switched pulse frequency was increased from 30.53 kHz to 58.74 kHz, along with an increase in the pump power from 45 mW to 250 mW. The spectral width was decreased from 7.31 nm to 2.04 nm, and this change was duly recorded. The Q-switched fiber laser demonstrated has good output characteristics and can be applied to scientific research, medical treatment, industrial processing and other fields.

A New Insect-Scale Piezoelectric Robot With Asymmetric Structure

To realize the switching of the multiple locomotion modes, a new insect-scale piezoelectric robot with asymmetric structure is proposed, fabricated, and tested. The robot prototype has a weight of 32.8 g and size of 55 mm×50 mm×20 mm. Driven by two pieces of piezoelectric ceramics, working at six vibration modes, the piezoelectric robot can realize two kinds of linear motion and four kinds of circular motion by contact friction. Performance assessments show that the robot has a maximum velocity of 155 mm/s and a minimum motion radius of 45 mm. In addition, the robot can move at a speed up to 97 mm/s (100 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p-p</sub> ) with integrated drive device (45.7 g). The insect-scale piezoelectric robot has simple structure, but has multiple motion modes, large speed range, good output characteristics and fast response time, which provides a new idea for the design and driving of micro robot.

Study on the Point‐Contact Gate AlGaN/GaN High Electron Mobility Transistor with 0.1 μm Gate Length

The current collapse has been one of the most challenging problems in AlGaN/GaN high electron mobility transistors (HEMTs). In recent years, the virtual gate effect has been the most widely accepted cause of the current collapse effect. To effectively improve the current collapse effect and reduce the influence of the virtual gate effect on the device, a point‐contact gate AlGaN/GaN HEMT structure is proposed in this article. Tests show that the device has high transconductance, high cut‐off frequency, and good transfer, output, and breakdown characteristics. The maximum saturation drain current is 18 mA mm−1, the maximum transconductance is 200 mS mm−1, the breakdown voltage is 994 V, the maximum current gain is about 190 dB, and the cut‐off frequency is up to 206 GHz when the gate length and width are 0.1 μm × 0.001 μm. The experimental analysis shows that the point‐contact gate AlGaN/GaN HEMT structure shortens the gate length, thereby improving the virtual gate effect and effectively suppressing the current collapse effect, increasing the breakdown voltage of the device, and further improving the device performance, which lays the foundation for the future research of AlGaN/GaN HEMT.

Channel length effect of P3HT:ZnO hybrid blend layer on electrical characteristics of thin-film transistors

In this present work, p-type bottom gate-bottom contact OTFTs based on semiconductor polymer poly(3-hexylthiophene) (P3HT) incorporating zinc oxide nanoparticles (ZnO) (OTFTs-P3HT:ZnO hybrid blend) with various channel lengths (L=2.5 µm, 5 µm, 10 µm and 20 µm) and constant channel width (W=10 mm) were elaborated using solution-processed P3HT:ZnO thin films, as an active layer, deposited on a Si/SiO2 substrate, without any surface treatment, by spin coating technique, and then were characterized. ZnO nanoparticles are utilized as acceptors and electron extraction materials. The effect of the channel length variation on the electrical parameters of these transistors at room atmosphere in saturation regime, has been investigated in order to better understand the dependency between the electrical performance and the channel length variation effect. As p-channel transistors, the fabricated devices exhibit a considerable variation in electrical parameters such as amount of hysteresis (△Vhyst), threshold voltage (Vth), density of trapped charges (Ntrap), sub-threshold slope (SS), density of the interface trap (Dit), field-effect saturation mobility (µsat) and current ratio (Ion/Ioff) with the increase of the channel length. In this study, we report a significant improvement in the efficiency of our devices in terms of good output characteristics and good electrical parameters such as low threshold voltage, low Ioff current, reduction of trap density and better field-effect saturation mobility when the channel length increases. These particularly promising results offer the possibility of using these organic thin-film transistors in several application domains such as low-cost sensing and non-volatile memory devices.

A Compact Piezo-Inertia Actuator Utilizing the Double-Rocker Flexure Hinge Mechanism.

With a simple structure and control method, the piezo-inertia actuator is a preferred embodiment in the field of microprecision industry. However, most of the previously reported actuators are unable to achieve a high speed, high resolution, and low deviation between positive and reverse velocities at the same time. To achieve a high speed, high resolution, and low deviation, in this paper we present a compact piezo-inertia actuator with a double rocker-type flexure hinge mechanism. The structure and operating principle are discussed in detail. To study the load capacity, voltage characteristics, and frequency characteristics of the actuator, we made a prototype and conducted a series of experiment. The results indicate good linearity in both positive and negative output displacements. The maximum positive and negative velocities are about 10.63 mm/s and 10.12 mm/s, respectively, and the corresponding speed deviation is 4.9%. The positive and negative positioning resolutions are 42.5 nm and 52.5 nm, respectively. In addition, the maximum output force is 220 g. These results show that the designed actuator has a minor speed deviation and good output characteristics.

A study of a slim compact piezo inertia actuator

Most previously reported inertia actuators suffer from the problems of low speed and large size. To overcome these shortcomings, this study proposes a slim compact piezo inertia actuator based on the principle of stick–slip drive. Actuated by the transverse motion of a cantilever beam forming part of a monolithic elastomer, this actuator achieves a high velocity. The construction and basic operating principle of the actuator are discussed in detail. Commercial finite element analysis software is employed to determine the appropriate geometry for the monolithic elastomer. To study the actuator’s mechanical characteristics, a prototype is fabricated and a series of experimental tests are performed. According to the results of these tests, the maximum velocity and maximum load force are about 24.03 mm/s and 1.96 N, respectively, and the minimum step size is about 0.47 μm. It is shown that the inertia actuator based on a monolithic elastomer with a cantilever beam not only has a slim compact structure, but also exhibits good output characteristics.

Grid-current-sensorless control of grid-forming inverter with LCL filter

As the grid impedance increases, the grid strength gradually becomes weak. In order to have good output characteristics in weak grid, grid-forming (GFM) inverters with LCL filter have gradually become popular. This paper studies grid-current-sensorless control which does not require grid current sensors. Firstly, the grid-current-sensorless control loops are given. Then, in order to make up for the inability to sample the actual grid current, a grid current estimator, which is derivative operator free and low-complexity, is proposed. And the robustness and accuracy of the estimator is verified by simulation. Afterwards, to demonstrate that this control operates stably when the grid strength changes, a joint small-signal stability analysis combining the control strategy and circuit topology is presented. The theoretical feasibility of the control is proved. Finally, to verify the robustness of the control under different grid strengths, the experiments are carried out on a 20kW GFM inverter. The results show that the proposed control has satisfactory steady-state and dynamic performance whether under strong grid or weak grid.

Dynamic stable ring resonator for high-power continuous single-frequency lasers: conditions for a compact resonator.

When considering dynamically stable resonators, ring lasers are good choices because they have a stability interval that is twice as large as that of linear resonators and sensitivity to misalignment decreasing with pump power; however, the literature does not provide easy design guidelines. A ring resonator utilizing Nd:YAG side pumped by diodes allowed single-frequency operation. The output single-frequency laser had good output characteristics; however, the overall length of the resonator did not allow for building a compact device with low misalignment sensitivity and larger spacing between longitudinal modes which could improve single-frequency performance. Based on previously developed equations, which allow for ease of design of a ring dynamically stable resonator, we discuss how to build an equivalent ring resonator, aiming to building a shorter resonator with the same stability zone parameters. The study of the symmetric resonator containing a pair of lenses allowed us to find the conditions to build the shortest possible resonator.

Microsphere assisted pumping of the microchip laser for good output characteristics

The microsphere is directly coupled with a microchip laser for efficient pumping of the laser crystal without using bulky coupling optics. It produces high optical density pumping along the laser crystal resulting in laser emission with a reduced full width half maximum at low threshold pump power. Microsphere-assisted pumping of the continuous wave laser output provides higher optical efficiency of 57% with a pump power of 110 mW than the plain laser crystal, which is only about 10%. It can miniaturize existing microchip laser systems to produce low-cost portable handheld devices.

(Digital Presentation) Effect of Active Layer Thickness on Organic Thin-Film Transistors

ABSTRACT: Thin-Film Transistors (TFTs) are a substantial technological advancement in recent decades for various applications. The source/drain electrode layer and organic active layer thicknesses of Organic Thin-Film Transistors (OTFTs) should be optimized for better device performance. Organic electronics have been used for a wide range of applications, including flexible screens, smart digital devices, and photovoltaic cells, because of their flexibility and environmental sensitivity. The OTFT has the capability to match the efficiency of thin-film amorphous Silicon transistors, while also being companionable with low-temperature solution/printing-processed fabrication on flexible coupling substrates. The OTFTs are a valuable tool for determining unipolar carrier transport parameters in various situations.In this present research work, authors have utilized the concept of OTFTs in the assessment of bipolar transport properties in active layer blends. It offers a strategy to improve the precision of the assessment. Thereafter, in this this research work, impacts of active layer thickness on physical parameters of OTFT device performance have been realized. The 2D numerical device simulators have been used to examine the proposed OTFT structures. The discussion focuses on the various characteristics and parameters of OTFTs. The OTFTs are transistors that manage electric current flow using organic semiconductors as an active layer. The output and transfer characteristics of various OTFT structures have been used to calculate the performance characteristics of OTFTs. Optimizing the OTFT's organic active layer thickness is critical for high device performance. Both photo-current and photo-responsivity exhibit the same variation trend with increasing organic active layer thicknesses, increasing rapidly for a while and then tending to saturate at high values. The research findings demonstrate the impact of these parameters on device performance and temperature and the need to optimize these variables in the device. The carrier mobility of the high-performance P3HT: PCBM-based OTFT structure was approximately 10 cm2/Vs, and an ON/OFF current ratio of ~103. These results are compatible with those OTFTs fabricated previously. Research Methodology, Results, and Discussions A schematic structure is shown in Figure 1(a) proposed structure top view, and 1(b) a side view of the proposed structure used for simulation. Top-gate OTFT and bottom-gate OTFT geometrical structures have been used in this OTFT. The device's contact resistance, field mobility, and threshold voltage degrade subjected to bias stress. Since top-gate OTFT has a higher device degradation, the authors used bottom-gate OTFT. Due to the distinct properties here in this work the authors utilized conventional materials such as a blend of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM) as the active layer. A P3HT: PCBM mix is simulated with an electronic device simulator and analyses the variation in active layer thickness that affects the device's performance and the factors that influence the performance of the device in this research work. The output and transfer characteristics of OTFTs have been realized using proper boundary conditions and OTFT physics. The proposed OTFT structures' output and transfer characteristics have been evaluated, and the simulated results show that the optimized structure's drain current (Id, max) is ~2.85 μA. The obtained results show that the device has good transfer and output characteristics at lower gate voltages. With increasing organic active layer thicknesses, both photo-current and photo-responsivity exhibit the same variation trend of increasing sharply at first and then tending to saturate at high values. Conclusion The simulation results examined the performance of devices built with bottom-gate OTFTs. A detailed analysis of the influence of active layer thickness on the OTFT configuration was realized. The device has the advantage of operating at a lower gate voltage, transforming it into a gate efficient control device. The operation at a lower voltage improves electrical stability. The electric field of the OTFT is 1.4x106 V/cm is obtained. The ON/OFF current ratio is higher. The outcomes of this analysis have been optimized and extracted after being tested in various contexts. The findings demonstrated that the suggested concept might be used to make rollable active-matrix displays, nonvolatile memory, sensors, and printed electronic devices. This work also reduces the SCEs and shows more efficient performance than traditional MOSFETs. Together with all application areas, the most important research area has been argued to be the simple manufacturing technique of OTFT with low production cost and non-breakable impacts that can be bent and folded. This device will be optimized with fabrication using these materials in the future, and thereafter, its characteristic will be verified with the simulated results. Figure 1

Simulation and Study of PEMFC System Directly Fueled by Ammonia Decomposition Gas

Ammonia can be stored as a liquid under relatively easy conditions (Ambient temperature by applying 10 bar or Ambient pressure with the temperature of 239 K). At the same time, liquid ammonia has a high hydrogen storage density and is, therefore, a particularly promising carrier for hydrogen storage. At the same time, the current large-scale industrial synthesis of ammonia has long been mature, and in the future, it will be possible to achieve a zero-emission ammonia regeneration cycle system by replacing existing energy sources with renewable ones. Ammonia does not contain carbon, and its use in fuel cells can avoid NOx production during energy release. high temperature solid oxide fuel cells can be directly fueled by ammonia and obtain good output characteristics, but the challenges inherent in high temperature solid oxide fuel cells greatly limit the implementation of this option. Whereas PEMFC has gained initial commercial use, however, for PEMFC, ammonia is a toxic gas, so the general practice is to convert ammonia to pure hydrogen. Ammonia to hydrogen requires decomposition under high temperature and purification, which increases the complexity of the fuel system. In contrast, PEMFC that can use ammonia decomposition gas directly can simplify the fuel system, and this option has already obtained preliminary experimental validation studies. The energy efficiency of the system obtained from the preliminary validation experiments is only 34–36%, which is much lower than expected. Therefore, this paper establishes a simulation model of PEMFC directly using ammonia decomposition gas as fuel to study the maximum efficiency of the system and the effect of the change of system parameters on the efficiency, and the results show that the system efficiency can reach up to 45% under the condition of considering certain heat loss. Increasing the ammonia decomposition reaction temperature decreases the system efficiency, but the effect is small, and the system efficiency can reach 44% even at a temperature of 850°C. The results of the study can provide a reference for a more scientific and quantitative assessment of the potential value of direct ammonia decomposition gas-fueled PEMFC.

Transparent All-Oxide Hybrid NiO:N/TiO2 Heterostructure for Optoelectronic Applications

Nickel oxide (NiO) is a p-type oxide and nitrogen is one of the dopants used for modifying its properties. Until now, nitrogen-doped NiO has shown inferior optical and electrical properties than those of pure NiO. In this work, we present nitrogen-doped NiO (NiO:N) thin films with enhanced properties compared to those of the undoped NiO thin film. The NiO:N films were grown at room temperature by sputtering using a plasma containing 50% Ar and 50% (O2 + N2) gases. The undoped NiO film was oxygen-rich, single-phase cubic NiO, having a transmittance of less than 20%. Upon doping with nitrogen, the films became more transparent (around 65%), had a wide direct band gap (up to 3.67 eV) and showed clear evidence of indirect band gap, 2.50–2.72 eV, depending on %(O2-N2) in plasma. The changes in the properties of the films such as structural disorder, energy band gap, Urbach states and resistivity were correlated with the incorporation of nitrogen in their structure. The optimum NiO:N film was used to form a diode with spin-coated, mesoporous on top of a compact, TiO2 film. The hybrid NiO:N/TiO2 heterojunction was transparent showing good output characteristics, as deduced using both I-V and Cheung’s methods, which were further improved upon thermal treatment. Transparent NiO:N films can be realized for all-oxide flexible optoelectronic devices.

Improved Reliability of 278 nm Deep Ultraviolet AlGaN-Based Flip-Chip Light Emitting Diodes by Using ITO/Al Contact

We investigated the electrical and optical performance and reliability of 278 nm deep ultraviolet (DUV) AlGaN-based flip-chip light-emitting diodes (FCLEDs) fabricated with ITO/Al and reference Ni/Au contacts. The DUV FCLEDs with the Ni/Au and ITO/Al contacts yielded forward voltages of 6.52 and 6.65 V at 50 A cm−2 and light output of 6.36 and 10.06 mW at 50 A cm−2, respectively. The ITO/Al-based FCLEDs produced higher Wall plug efficiency (WPE) (3.04% at 50 A cm−2) than the Ni/Au-based samples (1.96%). The ITO/Al-based FCLEDs revealed 55% higher WPE at 50 A cm−2 than the Ni/Au-based sample. For both of the samples, the output power decreased with increasing operation time at 100 A cm−2. For example, after 2000 h, the Ni/Au and ITO/Al-based FCLEDs showed a reduction in the output power by 37% and 22%, respectively. Despite the good output characteristics, the ITO/Al contact-based FCLEDs exhibited higher forward bias voltages than the Ni/Au-based sample. Based on the energy dispersive X-ray spectroscopy (EDS) depth profiles, high-angle annular dark field (HAADF), and electron energy loss spectroscopy (EELS) results, reason for the increase in the forward voltage of ITO/Al-based FCLEDs is described and discussed.

Chaos‐Based Engineering Applications with a 6D Memristive Multistable Hyperchaotic System and a 2D SF‐SIMM Hyperchaotic Map

In recent years, the research of chaos theory has developed from simple cognition and analysis to practical engineering application. In particular, hyperchaotic systems with more complex and changeable chaotic characteristics are more sensitive and unpredictable, so they are widely used in more fields. In this paper, two important engineering applications based on hyperchaos pseudorandom number generator (PRNG) and image encryption are studied. Firstly, the coupling 6D memristive hyperchaotic system and a 2D SF‐SIMM discrete hyperchaotic mapping are used as the double entropy source structure. The double entropy source structure can realize a new PRNG that meets the security requirements, which can pass the NIST statistical test when the XOR postprocessing method is used. Secondly, based on the double entropy source structure, a new image encryption algorithm is proposed. The algorithm uses the diffusion‐scrambling‐diffusion encryption scheme to realize the conversion from the original plaintext image to the ciphertext image. Finally, we analyze the security of the proposed PRNG and image encryption mechanism, respectively. The results show that the proposed PRNG has good statistical output characteristics and the proposed image encryption scheme has high security, so they can be effectively applied in the field of information security and encryption system.

Pseudorandom Number Generator Based on Three Kinds of Four-Wing Memristive Hyperchaotic System and Its Application in Image Encryption

In this paper, we propose a method to design the pseudorandom number generator (PRNG) using three kinds of four-wing memristive hyperchaotic systems (FWMHSs) with different dimensions as multientropy sources. The principle of this method is to obtain pseudorandom numbers with good randomness by coupling XOR operation on the three kinds of FWMHSs with different dimensions. In order to prove its potential application in secure communication, the security of PRNG based on this scheme is analyzed from the perspective of cryptography. In addition, PRNG has passed the NIST 800.22 and ENT test, which shows that PRNG has good statistical characteristics. Finally, an image encryption algorithm based on PRNG is adopted. In the encryption algorithm, the optimized Arnold matrix scrambling method and the diffusion processing based on XOR are used to obtain the final encrypted image. Through the evaluation of encryption performance, it is concluded that there is no direct relationship between the pristine image and encrypted image. The results show that the proposed image encryption scheme has good statistical output characteristics and security performance in line with cryptography.

Output Characteristics of Graphene Field Effect Transistors

The use of graphene, which has high mobility of charge carriers, high thermal conductivity and a number of other positive properties, is promising for the creation of new semiconductor devices with good output characteristics. The aim was to simulate the output characteristics of field effect transistors containing graphene using the Monte-Carlo method and the Poisson equation.Two semiconductor structures in which a single layer (or monolayer) of graphene is placed on a substrate formed from 6H-SiC silicon carbide material are considered. The peculiarity of the first of them is that the contact areas of drain and source were completely located on the graphene layer, the length of which along the longitudinal coordinate was equal to the length of the substrate. The second structure differed in that the length of the graphene layer was shortened and the drain and source areas were partly located on the graphene layer and partly on the substrate.The main output characteristics of field-effect transistors based on the two semiconductor structures considered were obtained by modeling. The modeling was performed using the statistical Monte Carlo method. To perform the simulation, a computational algorithm was developed and a program of numerical simulation using the Monte-Carlo method in three-dimensional space using the Poisson equation was compiled and debugged.The results of the studies show that the development of field-effect transistors using graphene layers can improve the output characteristics – to increase the output current and transconductance, as well as the limit frequency of semiconductor structures in high frequency ranges.