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OFDM, FBMC, Channel estimation, Interference cancellation, Deep learning, And recurrent neural network, Telecommunication, TK5101-6720, Electronics, and TK7800-8360

Abstract FBMC is a pivotal system in 5G, serving as a cornerstone for efficient use of available bandwidth while simultaneously meeting stringent requirements for high spectral efficiency. Notably, FBMC harnesses the power of multicarrier modulation (MC), a good alternative to orthogonal frequency division multiplexing (OFDM) technology that supports fourth-generation (4G) systems. The wireless communications field is full of challenges, the most important of which are channel estimation and interference cancellation, both of which deserve comprehensive study to increase the efficiency of data transmission. In this paper, our investigation takes a deliberate step towards the convergence of two prominent modulation models: OFDM and FBMC. We specifically contrast these modulation techniques with the intricate field of joint channel estimation and interference cancellation (JCEIC). In this research study, we take advantage of recurrent neural networks' (RNNs') efficiency as a vehicular channel to perform precise channel estimation and recovery of uncorrupted transmitted signals, thereby lowering the bit error rate (BER). Our channel estimation for a dual selective channel is based on the thoughtful placement of pilots scattered over the temporal and frequency dimensions, and is further improved by the interference cancellation method of low complexity that was selected. Our JCEIC proposal aims to integrate RNNs carefully, using the output sequences of JCEIC algorithms as useful inputs to this neural architecture. By clearly demonstrating a decrease in BER as compared to traditional approaches, it is evident that the performance of the novel approach is near to that of a perfect channel. Additionally, a comparison of the performance of FBMC and OFDM systems at various signal-to-noise ratios reveals a clear performance divide that favors the former in terms of system efficiency. The BER is restricted by FBMC to a commendable threshold of less than 0.1 at a modest 5 dB, continuing the higher trend started by its improved RNN-based channel estimate. The accuracy of channel estimation is clearly improved by this paradigm shift, and the computing complexity typical of 5G networks is also clearly reduced.

Deep learning, Internet of things (IoT), Physical layer security, Active eavesdropping detection, BP neural network, Telecommunication, TK5101-6720, Electronics, and TK7800-8360

Abstract Considering the variety of Internet of Things (IoT) device types and access methods, it remains necessary to address the security challenges we currently encounter. Physical layer security (PLS) can offer streamlined security solutions for the next generation of IoT networks. Presently, we are witnessing the application of intelligent technologies including machine learning (ML) and artificial intelligence (AI) for precise prevention or detection of security breaches. Active eavesdropping detection is a physical layer security-based method that can differentiate wireless signals between wireless devices through feature classification. However, the operation of numerous IoT devices operate in environments characterized by low signal-to-noise ratios (SNR), and active eavesdropping attack detection during communication is rarely studied. We assume that the wireless system comprising an access point (AP), K authorized users and a proactive eavesdropper (E), following the framework of transforming wireless signals at AP into organized datasets that this article proposes a BP neural network model based on deep learning as a classifier to distinguish eavesdropping and non-eavesdropping attack signals. By conducting experiments under SNRs, the numerical results show that the proposed model has stronger robustness and detection accuracy can significantly improve the up to 19.58% compared with the reference approach, which show the superiority of our proposed method.

DC‐DC power convertors, power electronics, resonant power convertors, zero voltage switching, Electronics, and TK7800-8360

Abstract Common inductor (CIM) and common capacitor (CCM) passive current‐sharing methods have the advantages of simple implementation and low cost. However, there is still a lack of detailed comparative research on the two methods, which makes researchers confused when choosing the two methods. To provide clear scheme guidance, this paper provides a detailed comparison of the performance of the two methods. Firstly, this paper reveals the difference between the current waveforms of the two methods, that is, the current waveform of the CIM method is distorted, while the CCM method is non‐distorted. Then, the mechanism of the above phenomenon is analysed in depth. Secondly, for comparing the current sharing performance of the two methods, the first harmonic approximation (FHA) equivalent circuit model considering parasitic parameters is established to obtain the system's current sharing error model, and the parameter sensitivity analysis is provided. Finally, the relationship between the current waveform, current sharing error, and load ripple of the two methods is discussed. Then, based on the two methods, a more attractive common resonate tanks (CRT) current‐sharing method is proposed. The correctness of the view in this paper has been verified by extensive simulations and experiment results.

buck converter, cell balancing, cell voltage, lithium‐ion battery, reconfigurable battery system, state of charge, Electronics, and TK7800-8360

Abstract Lithium‐ion batteries have a very wide application range. They can power up small electronic devices such as smart watches to larger electric vehicles. Due to its varied range of applications, they come in different packaging and in such battery packs, even when individual cell voltage exceeds by a few milli‐volts above 4.2 V, it may result in thermal runaway and explode the cell. During discharge cycle, cell imbalances hinder the use of battery to its full capacity. This in turn decreases the battery lifetime. The individual battery cells should be equalized on a regular basis to keep the imbalances to a minimum and to have a good battery life. The process of balancing the individual cell charges by measuring the cell state of charge (SoC) and its voltage in a battery pack is known as cell balancing. This paper details an active cell balancing technique that uses a buck converter for balancing a series connected battery pack of lithium‐ion cells. A buck converter along with a pair of MOSFET switches for each cell, one turned on for charging the cell and the other one turned on while discharging the cell is used in this experiment. An algorithmic model suitable for reconfigurable battery systems that measures the individual cell voltages and is developed for balancing a pack of series connected Li‐ion battery cells. The developed model is simulated using MATLAB for verifying its performance. A state of charge of 25% is maintained across the cells and when SoC value drops below this even a difference of 0.02% is sensed by the algorithm to initiate balancing function. This balancing is found to take 275 ms to balance three 3.7 V batteries and thus the model is found to respond faster. The results show that this method can self‐adaptively attain satisfactory performance within a limited equalizing period.

DC–AC power convertors, fault diagnosis, invertors, mathematical analysis, power electronics, interval sliding mode observer, Electronics, and TK7800-8360

Abstract Because of uncertain random noise and unknown disturbance, the observer‐based inverter fault diagnosis meets the problems of large deviation of current observation value and high false alarm rate. An inverter open‐circuit fault diagnosis method is proposed via residual performance evaluation. Firstly, the interval sliding mode observer is constructed by combining the interval observer with the sliding mode observer. Three phase current estimates are obtained and current residuals are calculated. Secondly, the residual performance indicators are calculated using the evaluation function. The fault detection is derived by comparing residual performance with the threshold. Thirdly, a residual information table is established based on the fault information contained in the residual for fault isolation. Finally, the proposed algorithm is validated on simulation and physical platforms. Compared with traditional observer‐based diagnostic methods, the introduction of residual performance evaluation improves the diagnostic speed by more than 50%. The interval sliding mode observer has higher estimation accuracy and anti‐interference ability in the presence of noise and external disturbances.

harmonic analysis, matrix convertors, PWM power convertors, Electronics, and TK7800-8360

Abstract The multiphase matrix converter outperforms the conventional three‐phase system with higher fault tolerance capability and higher power control competency. This paper discusses the direct control based on different possible switching combinations of a three‐phase to five‐phase matrix converter (MC). The proposed control topology significantly reduces the switching commutations in a switching cycle when compared with its counterpart. The control is based on the modified space vector pulse width modulation (SVPWM) strategy. The proposed space vector scheme intelligently selects the voltage vectors to get the desired output characteristics with the least possible switching transitions in a switching cycle. Three possible cases exist in controlling space vectors based on their magnitude, the number of active switching vectors, and their commutations. The results for three different cases of SVPWM have been presented and compared. The total harmonic distortion (THD) obtained in the output is lower in case 2; however, it suffers from a higher common‐mode voltage (CMV). The scheme has been successfully implemented and verified in hardware.

adaptive sliding mode control law, quasi‐Z‐source inverter, three‐phase photovoltaic grid‐connected, Electronics, and TK7800-8360

Abstract Considering the non‐linear characteristics of both the input and output of photovoltaic (PV) modules and quasi‐Z‐source inverters, as well as the unpredictable natural factors such as large disturbances caused by changes in illumination and temperature, an average state model for the PV quasi‐Z‐source inverter is established. This paper uses the output current of photovoltaic module, DC‐link capacitor voltage and its integral as state variables, then an adaptive reaching law with second‐order sliding mode characteristics is designed by combining with power reaching law and variable speed reaching law. By using the sliding mode controller based on the adaptive reaching law to control the stability of the DC‐link voltage of the quasi‐Z‐source inverter and the small capacitor voltage ripple, the photovoltaic system can operate stably at the maximum power point when the temperature and illumination conditions change abruptly, and the grid‐connected effect is improved. Through SIMULINK and RT‐LAB real‐time simulation, the effectiveness of the proposed adaptive sliding mode control strategy is verified when the environment changes, which effectively improves the dynamic response speed and grid‐connected effect of the system, and ensures the global robustness of the grid‐connected system.

harmonics suppression, phase locked loops, power grids, power harmonic filters, Electronics, and TK7800-8360

Abstract In order to attenuate the oscillations on the estimated frequency of a phase‐locked loop (PLL), the effective suppression of low‐order harmonics in grid voltage is a crucial issue in three‐phase grid‐connected inverters, which use the standard PLL based on a double second‐order generalized integrator (DSOGI‐PLL). Analysis shows that the SOGI module exerts a stronger filtering effect in generating the quadrature signal than the in‐phase signal. In this context, two novel cascaded SOGI module filtering structures have been developed, based on which the PLLs are proposed. In comparison to the previously proposed method for addressing the problem of input voltage harmonics, the proposed method has stronger filtering ability and can flexibly select the levels of SOGI module cascading based on the degree of grid voltage distortion to achieve a balance between system dynamic performance and filtering performance. The proposed PLLs' approximation small signal model is established, and the method for designing the system control parameters is also provided. In the case of frequency steps, phase angle jumps, harmonic injection, and unbalanced voltage sag, Matlab modelling and experimental results demonstrate that the proposed PLLs can efficiently extract the frequency and phase of the fundamental positive sequence component and behave better in steady‐state and dynamic performance.

condition monitoring, fault diagnosis, power MOSFET, reliability, Electronics, and TK7800-8360

Abstract SiC MOSFET modules are widely used for bidirectional wireless charging of electric vehicles. However, prolonged use can result in bond wire faults, leading to reliability issues. To address this problem, a non‐contact bond wire monitoring method that can be carried out using the charging coil of the wireless charging device is proposed. Here, two monitoring loops are constructed based on the circuit topology, and their impedance magnitudes are measured on the charging coil to avoid the influence of battery voltage on monitoring results. To detect the bond wire condition, the impedance magnitude difference of the two monitoring loops is chosen as an indicator, which is very sensitive to the bond wire lift‐off. However, the monitoring results may be influenced by the aging of resonant capacitors and the offset of the charging coil. In particular, the influence of the coil offset is significant. To mitigate this effect, a prognostic parameter calibration method is proposed. Experimental results confirm the effectiveness of the proposed method, which provides a promising solution for the reliable and safe operation of SiC MOSFET modules in wireless charging devices.

overvoltage, railways, RLC circuits, thyristors, transient analysis, Electronics, and TK7800-8360

Abstract The auto‐passing neutral section (ANS), applied in the traction substation or section post (SP), is one of the effective methods to improve the continuity of power supply, and the electromagnetic transient is the key issue impacting its application value. An equivalent switching circuit is established to reveal the causes of the electromagnetic transient. The suppression methods for reducing transient overvoltage and inrush current are proposed, adopting an improved RLC filter to suppress the transient overvoltage with low active power loss, and a switching strategy to minimize magnetic flux variation. The correctness of the proposed methods has been confirmed by simulation and experimental results, which can improve the transient performance and increase the practicality of the ANS.

PWM rectifiers, robust control, Electronics, and TK7800-8360

Abstract In this study, H∞ loop shaping is designed for single‐phase pulse width modulation (PWM) rectifier under current sensor gain faults. Pre‐compensator is used to obtain the desired loop shape at all frequencies and robust stabilization through the normalized coprime factorization. The mathematical model for the rectifier is developed to obtain the nominal plant transfer function, and two algebraic Riccati equations are used to solve the designed controller and obtain the loop shaping controller by combining the designed controller with the weights. ν‐gap metric is adopted to measure the magnitude of the current sensor gain fault that can be stabilized by the controller. The proposed controller is compared with H∞‐mixed sensitivity (H∞‐MS) controller. The robustness capability and dynamic performance is investigated and, hardware‐in‐loop experimental results show excellent balance between robustness and performance in the presence of current sensor gain faults.

DC–DC converters, hybrid voltage multiplier cells, renewable energy systems, super‐wide voltage gain, ultra‐low voltage stress, Electronics, and TK7800-8360

Abstract As the promising and ideal clean energies, wind and solar energy systems are in desperate need of high‐performance DC–DC converters to realize efficient and reliable energy transformation. Conventional DC–DC converters for renewable energy systems will work at extreme duty cycles and affect the system efficiency and reliability owing to their limited voltage gains and high‐voltage stress. In this paper, by adopting the hybrid voltage multiplier cells, two enhanced quadratic boost converters (EQBCs) which are highly desirable for renewable energy applications are proposed and analyzed. The EQBCs possess super‐wide voltage gain ranges and ultra‐low voltage stress; therefore, small duty cycle conditions can be achieved and components with low‐rated voltages can be chosen to decrease system volumes and increase system efficiencies. Besides, the EQBCs possess continuous input currents, which can realize small input current ripples and avoid the serious effect of pulsating current on the input sources. What's more, stable output voltages and simple controller circuits are realized by the EQBCs because of the common grounded structures of the input terminal, the single active switch and the output terminal. Detailed principle analyses, parameter designs, performance comparisons and experimental prototypes are conducted to verify the characteristics and feasibilities of the EQBCs.

AC–DC power convertors, energy storage, power transformers, short‐circuit currents, Electronics, and TK7800-8360

Abstract With the growing capacity of the distribution network, the probability of short circuit accidents gradually increases. Accidents such as deformation of distribution transformer windings, shift of laminations, fracture and even explosion of mechanical and insulation components caused by insufficient short‐circuit withstand ability seriously affect the safe and stable operation of the distribution network. The short‐circuit test proved to be an effective way to detect the performance of equipment under fault impact. A power source with supercapacitor is proposed here for short‐circuit test of 10 kV distribution transformers, which can realize the short‐circuit test application economically and flexibly with expandable capacity. First, the advantages and disadvantages of test power source by short‐circuit test generators, special power line, and the proposed method are compared. Second, the structure, working principle, design scheme, and control strategy of the novel short‐circuit testing device are introduced. Furthermore, a 14 MVA/5 MJ energy storage short‐circuit test power source is designed for the testing requirements of 10 kV/630 kVA distribution transformers. Finally, the simulations and experiments are used to verify its feasibility.

controllability, DC–DC power convertors, electric vehicles, power conversion, power electronics, Electronics, and TK7800-8360

Abstract In this study, a new multi input–multi output (MIMO) high step‐up DC–DC converter is proposed for battery charger applications. Continuous input current and capability of using several renewable energy sources with different voltage‐current characteristics are the main advantages of it. High voltage gain and low power losses on semiconductors are the other advantages of the proposed topology. In addition, the duty cycle of each input source is independent of other sources. The proposed converter has soft‐switching on some power diodes which leads to increasing the overall efficiency of the proposed topology. A laboratory prototype of the proposed topology in 12V–12 V/430 W is built and tested. The experimental results are verifying the proper performance of the proposed topology and confirm the theoretical analysis.

asymmetrical pulse width modulation, HB inverters, induction heating, power MOSFET, power system reliability, resonant converters, Electronics, and TK7800-8360

Abstract This paper presents a method that improves the reliability of half‐bridge (HB) series resonant inverters (SRI) for high‐frequency induction heating applications. Many industrial processes, like induction heat treatments, are very repetitive. This cyclical operation represents a strong limitation of the inverter's reliability, mainly due to the accelerated stress of the power semiconductors. This method consists in an enhanced asymmetrical pulse width modulation (EAPWM) that allows distributing the losses across the components, thereby reducing the cyclic increase in junction temperature of the power devices, and thus achieves a reliability that is more than twice as high as that achieved using traditional modulation methods. The work methodology includes a theoretical study of the HB inverter and a complete analysis of losses. The presented design rules have been used to implement a 25 kW, 100 kHz inverter. The use of silicon carbide (SiC) MOSFET transistors allows reaching an efficiency greater than 99%. The analytical results obtained have been experimentally validated by testing the inverter on an induction heating test bench.

Electronics, TK7800-8360, Materials of engineering and construction. Mechanics of materials, and TA401-492

Abstract Direct stimulation of peripheral nerves with implantable electrodes successfully provided sensory feedback to amputees while using hand prostheses. Longevity of the electrodes is key to success, which we have improved for the polyimide-based transverse intrafascicular multichannel electrode (TIME). The TIMEs were implanted in the median and ulnar nerves of three trans-radial amputees for up to six months. We present a comprehensive assessment of the electrical properties of the thin-film metallization as well as material status post explantationem. The TIMEs stayed within the electrochemical safe limits while enabling consistent and precise amplitude modulation. This lead to a reliable performance in terms of eliciting sensation. No signs of corrosion or morphological change to the thin-film metallization of the probes was observed by means of electrochemical and optical analysis. The presented longevity demonstrates that thin-film electrodes are applicable in permanent implant systems.

Dyna-Q-Max-Action, Reinforcement learning, Reverberation Doppler spread clutter, Cognitive sonar, Telecommunication, TK5101-6720, Electronics, and TK7800-8360

Abstract The Doppler shift of low-speed targets is frequently disturbed by the reverberation Doppler spread clutter under the shallow sea. The clutter is generated by underwater scatterers, which increases the difficulty of Doppler estimation. To solve this problem, a reverberation target resolution function based on the Doppler spread clutter statistical model is proposed in this paper. Through the width of reverberation Doppler clutter, this function adjusts the waveform parameters by determining whether the target is discriminable. In addition, the reverberation Doppler spread clutter is time-spatial varying and affected by grazing angle, waves, wind speed, fish and other effects. Thus, the sonar waveform parameters need to be adjusted constantly. Therefore, this paper combines the cognitive sonar based on reinforcement learning with the reverberation target resolution function to evaluate different waveforms in different environments. Consequently, the sonar can adjust the waveform parameters in real-time and obtain the optimal waveform in different environments. Meanwhile, in this paper, the action selection strategy of Dyna-Q reinforcement learning is optimized, and the model-based maximum action selection Dyna-Q algorithm (Dyna-Q-Max-Action) is proposed. Compared with the traditional Dyna-Q and Q-learning algorithms, the proposed algorithm needs fewer episodes. Finally, numerical simulation verified the effectiveness of the proposed algorithm.

Aero-engine, Vibration signal, Wavelet transform method, Fault analysis, Telecommunication, TK5101-6720, Electronics, and TK7800-8360

Abstract A single type of signal processing means that it is difficult to analyze vibration signals comprehensively and effectively. By comprehensively using wavelet analysis techniques, a comprehensive and in-depth study of aero-engine vibration conditions is realized as a way to carry out health management. By introducing various types of wavelet analysis techniques and using Labview2022 programming, corresponding signal processing tools are developed for the analysis of the collected vibration signals. The comprehensive analysis of aero-engine vibration signals based on the wavelet transform method is realized, and the corresponding products are successfully applied in engineering practice.

UAV swarm, Multi-narrow type obstacles, Dual-game, Flocking obstacle avoidance algorithm, Telecommunication, TK5101-6720, Electronics, and TK7800-8360

Abstract Due to the advantages of rapid deployment, flexible response and strong invulnerability, unmanned aerial vehicle (UAV) swarm has been widely applied in collaborative warfare and emergency communication. However, UAV swarm in complex environments is prone to chaotic collapse due to obstructions. A UAV swarm obstacle avoidance system model for multi-narrow type obstacles is established. Due to the fact that only one UAV is allowed to pass through each small hole at any given moment, addressing the issue of congestion caused by swarming effects becomes crucial in addition to managing the competitive allocation of multiple UAVs to multiple holes. Aiming at this problem, a dual-game real-time obstacle avoidance scheme is proposed for UAV swarm with multi-narrow type obstacle scenarios, which divides the flight process of the UAV swarm into two stages: maintaining the flight state of the UAV swarm unchanged when no obstacles are encountered, and implementing matching separation and motion state switching by means of dual-game strategy when facing multi-narrow type obstacles, ultimately achieving orderly passage after multiple rounds of games. For the proposed scheme, a dual-game based Flocking (DGF) obstacle avoidance algorithm is proposed. Specifically, the motion state of each UAV obtained from the game is parameterized and integrated with the Flocking algorithm to calculate the motion control input for each UAV. The solution is iteratively obtained until the UAV swarm completes the obstacle avoidance. Simulation results demonstrate that the proposed DGF algorithm not only enables smooth obstacle avoidance for the UAV swarm in multi-narrow type obstacle scenarios, but also effectively resolves the internal chaos problem in the UAV swarm, thereby preventing rigid collisions.

active filters, harmonic analysis, neural nets, Electronics, and TK7800-8360

Abstract There have been concerns raised on load non‐linearity as more and more load types are being introduced into the radar power supply system. The non‐linear load produces harmonic current while it seriously threatens the normal and safe operation environment of other system equipment. It can be difficult to design shunt active power filter (APF) to eliminate the harmonic effect while achieving stability and reliability. This paper designs a hybrid optimization shunt active power filter, which adopts enhanced echo state network (ESN) to predict harmonics and reduce the delay problem in traditional control. The prediction performance of enhanced ESN is verified by simulation. The modelling and simulation of the hybrid optimization shunt APF are completed in Simulink, and the parameters of APF are reset according to the radar power supply system. Furthermore, a prototype based on DSP TMS320F28335 was developed to test whether the theory is feasible and accurate. The experimental results demonstrate that the APF with harmonic prediction has improved steady‐state response performance and rapid dynamic response performance.