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This paper aims to examine the design and control of a symmetric multilevel inverter (MLI) using grey wolf optimization and differential evolution algorithms.

The optimal modulation index along with the switching angles are calculated for an 11 level inverter. Harmonics are used to estimate the quality of output voltage and measuring the improvement of the power quality.

The simulation is carried out in MATLAB/Simulink for 11 levels of symmetric MLI and compared with the conventional inverter design. A solar photovoltaic array-based experimental setup is considered to provide the input for symmetric MLI. Field Programmable Gate Array (FPGA) based controller is used to provide the switching pulses for the inverter switches.

Attempted to develop a system with different optimization techniques.

Multi‐level diode‐clamped inverters have the challenge of capacitor voltage balancing when the number of DC‐link capacitors is three or more. On the other hand, asymmetrical DC‐link voltage sources have been applied to increase the number of voltage levels without increasing the number of switches. The purpose of this paper is to show that an appropriate multi‐output DC‐DC converter can resolve the problem of capacitor voltage balancing and utilize the asymmetrical DC‐link voltages advantages.

A family of multi‐output DC‐DC converters is presented in this paper. The application of these converters is to convert the output voltage of a photovoltaic (PV) panel to regulate DC‐link voltages of an asymmetrical four‐level diode‐clamped inverter utilized for domestic applications. To verify the versatility of the presented topology, simulations have been directed for different situations and results are presented. Some related experiments have been developed to examine the capabilities of the proposed converters.

The three‐output voltage‐sharing converters presented in this paper have been mathematically analysed and proven to be appropriate to improve the quality of the residential application of PV by means of four‐level asymmetrical diode‐clamped inverter supplying highly resistive loads.

This paper shows that an appropriate multi‐output DC‐DC converter can resolve the problem of capacitor voltage balancing and utilize the asymmetrical DC‐link voltages advantages and that there is a possibility of operation at high‐modulation index despite reference voltage magnitude and power factor variations.

The purpose of this paper is to propose a DC-port voltage balance strategy realizing it by logic combination modulation (LCM). This voltage balance strategy is brief and high efficient, which can be used in many power electronic devices adopting the cascaded H-bridge rectifier (CHBR) such as power electronic transformer (PET).

The CHBR is typically as a core component in the power electronic devices to implement the voltage or current conversion. The modulation method presented here is aiming to solve the voltage imbalance problem occurred in the CHBR with more stable work station and higher reliability in ordinary operating conditions. In particular, by changing the switch states smoothly and quickly, the DC-port voltage can be controlled as the ideal value even one of the modules in CHBR is facing the load-removed problem.

By using the voltage balance strategy of LCM, the problem of voltage imbalance occurring in three-phase cascaded rectifiers has been solved properly. With the lower modulation depth, the efficiency of the strategy is shown to be better and stronger. The strategy can work reliably and quickly no matter facing the problem as load-removed change or the ordinary operating conditions.

The limitation of the proposed DC-port voltage balance strategy is calculated and proved, in a three-module CHBR, the LCM could balance the DC-port voltage while one module facing the load-removed situation under 0.83 modulation depth.

This paper provides a useful and particular voltage balance strategy which can be used in the topology of three-phase cascaded rectifier. The value of the strategy is that a brief and reliable voltage balance method in the power electronic devices can be achieved. What is more, facing the problem, such as load-removed, in outport, the strategy can response quickly with no switch jump and switch frequency rising.

The high-frequency common-mode voltage introduced by power converters, using conventional modulation techniques, results in common-mode current that has the potential to cause physical damage to the shaft and bearings of electric drives as well as unwanted tripping of ground fault relays in motor drives and electrical networks. The paper aims to provide a complete elimination of common mode voltage using a matrix converter (MC) with a new modulation strategy that reduces the size of the power converter system considerably. Further, a new MC topology is proposed to eliminate the common mode voltage with improved voltage transfer ratio (VTR).

The direct MC topology is selected, as it is the only converter topology that has the potential to eliminate common mode voltage in direct AC to AC systems. Using the rotating space vector technique, common mode voltage is eliminated but this reduces the VTR of the converter. To improve the VTR, a modified MC topology with a modified rotating space vector strategy is proposed. In addition, for improving the power factor at the input, the input current control strategy is developed.

The use of rotating space vector technique eliminates the common mode voltage even under all input abnormalities like unbalance and harmonics. By applying positive and negative rotating space vectors, input power factor control can be achieved. However, the control range is limited from unity power factor to the output power factor. It is observed that in the current controlled technique the modulation index reduces further. It is also found that there is a reduction in switching stresses of individual switches in proposed topology compared to direct MC topology.

In this paper, a modified rotating space vector technique is applied to the proposed converter topology for elimination of common mode voltage with an increased VTR. The topology can be used for common mode voltage elimination in existing electric drives without the need for modifying the drive system.

Non-orthogonal multiple access (NOMA) is a much hopeful scheme, which is deployed to enhance the spectral efficiency (SE) significantly, and it also enhances the massive access that has attained substantial concern from industrial and academic domains. However, the deployment of superposition coding (SC) at the receiver side resulted in interference. For reducing this interference, “multi-antenna NOMA” seems to be an emerging solution. Particularly, by using the channel state information at the transmitter, spatial beam forming could be deployed that eliminates the interference in an effective manner.

This survey analyzes the literature review and diverse techniques regarding the NOMA-based spatial modulation (SM) environment. It reviews a bunch of research papers and states a significant analysis. Initially, the analysis depicts various transmit antenna selection techniques that are contributed in different papers. This survey offers a comprehensive study regarding the chronological review and performance achievements in each contribution. The analytical review also concerns on the amplitude phase modulation (APM) selection schemes adopted in several contributions. Moreover, the objective functions adopted in the reviewed works are also analyzed. Finally, the survey extends with various research issues and its gaps that can be useful for the researchers to promote improved future works on NOMA-based SM.

This paper contributes to a review related to NOMA-based SM systems. Various techniques and performance measures adopted in each paper are analyzed and described in this survey. More particularly, the selection of transmission antenna and APM are also examined in this review work. Moreover, the defined objective function of each paper is also observed and made a chronological review as well. Finally, the research challenges along with the gaps on NOMA-based SM systems are also elaborated.

This paper presents a brief analysis of NOMA-based SM systems. To the best of the authors’ knowledge, this is the first work that uses NOMA-based SM systems to enhance SE.

This paper aims to provide a sensor for fast, sensitive and selective ethylene (C₂H₄) concentration measurements.

The paper developed a sensor platform based on tunable laser absorption spectroscopy with a 3,266-nm interband cascade laser (ICL) as an optical source and a hollow waveguide (HWG) as a gas cell. The ICL wavelength was scanned across a C₂H₄ strong fundamental absorption band, and an interference-free C₂H₄ absorption line located at 3,060.76 cm⁻¹ was selected. Wavelength modulation spectroscopy with the second harmonic detection (WMS-2f) technique was used to improve the sensitivity. Furthermore, the HWG gas cell can achieve a long optical path in a very small volume to improve the time response.

The results show excellent linearity of the measured 2f signal and the C₂H₄ concentration with a correlation coefficient of 0.9997. Also, the response time is as short as about 10 s. The Allan variance analysis indicates that the detection limit can achieve 53 ppb with an integration time of 24 s.

The ethylene sensor has many meaningful applications in environmental monitoring, industrial production, national security and the biomedicine field.

The paper provides a novel sensor architecture which can be a versatile sensor platform for fast and sensitive trace-gas detection in the mid-infrared region.

The purpose of this paper is to apply technical analysis to some leading Islamic indices and explore if these indices are amenable to the same kind of analysis as applied to conventional indices and whether technical analysis, in contrast with fundamental analysis, produces distinct or superior return.

In this paper, some basic tools of TA to Dow Jones Islamic Market US Index (IMUS) is applied in comparison with the three major market indices: Dow Jones Industrial Average, S&P 500 Index and NASDAQ 100. For TA, we apply moving averages, MACD and Stochastics as indicators. The paper is written particularly for those with interest in Islamic finance, but not necessarily familiar with TA. This paper thus also explores some Shariah-related issues in effectively applying TA.

The comparative analysis shows that the performance based on IMUS can be improved, when TA is applied.

Robust tools of TA play an important role in market research. This paper probably is the first to apply TA in the context of Islamic finance. Because the scope of this paper is limited (only Dow Jones Islamic USA Index and comparison with three leading market indices), more in-depth research is needed and possible, which it is hoped this paper will encourage.

The successful application of the basic TA tools to Islamic index will encourage the practitioners of Islamic finance to research and explore further uses and effectiveness of TA on other Islamic products.

This paper is probably the first application of TA to Islamic finance markets, written especially for those who take active interest in the financial market from Islamic perspective.

To provide an approach to active vibration reduction of flexible spacecraft actuated by on‐off thrusters during attitude control for spacecraft designers, which can help them analysis and design the attitude control system.

The new approach includes attitude controller acting on the rigid hub, designed by using pulse‐width pulse‐frequency modulation integrated with component command technique, and the piezoelectric material elements as sensors/actuators bonded on the surface of the beam appendages for active vibration suppression of flexible appendages, designed by optimal positive position feedback (OPPF) control technique. The OPPF compensator is devised by setting up a cost function to be minimized by feedback gains, which are subject to the stability criterion at the same time, and an extension to the conventional positive position feedback control design approach is investigated.

Numerical simulations for the flexible spacecraft show that the precise attitude control and vibration suppression can be accomplished using the derived vibration attenuator and attitude control controller.

Studies on how to control the on‐off actuated system under impulse disturbances are left for future work.

An effective method is proposed for the spacecraft engineers planning to design attitude control system for actively suppressing the vibration and at the same time quickly and precisely responding to the attitude control command.

The advantage in this scheme is that the controllers are designed separately, allowing the two objectives to be satisfied independently of one another. It fulfils a useful source of theoretical analysis for the attitude control system design and offers practical help for the spacecraft designers.

This paper aims to investigate the common-mode voltage (CMV) issue of a three-phase four-leg voltage-source inverter. A new space vector modulation method, named as three-dimensional active zero state Pulse-width modulation (PWM) (3-D AZSPWM), is proposed to reduce the CMV level.

PWM is a general method to generate the switching signals of the power converters in order to obtain high-quality output voltages. However, the CMV produced by PWM methods has become a serious problem. 3-D AZSPWM is proposed to solve this issue. In 3-D AZSPWM, instead of using zero voltage vectors with high CMV level, appropriate complementary non-zero vectors are introduced to synthesize reference vector. The proposed method is classified into four types of AZSPWM1(a), AZSPWM1(b), AZSPWM2(a) and AZSPWM2(b) based on different complementary vectors chosen for each type. An extend software simulation using MATLAB/Simulink is performed to verify the superior performance of the proposed methods.

Compared to other reduced CMV methods, the proposed method not only reduces the CMV but also retains the positive characteristics of the three-dimensional classical space vector PWM (3-D CSVPWM).

The proposed method does not suffer from linear modulation region limitation and also does not impose additional switching loss. Furthermore, calculated output voltage harmonic distortion factor illuminates acceptable quality of output voltage produced by the proposed method.

Optoelectronic components such as lasers and avalanche photodiodes have already revolutionised long distance transmission, and yet the technology is still in its infancy. Future generations of optoelectronic components will see the increasing integration of electronic, optoelectronic and optical functions on single chips, bringing about dramatic improvements in performance and the lower costs that will be required for widescale introduction of broadband networks and services.