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The frequency‐domain dielectric spectroscopy (FDS) of humid insulating paper has been measured at different temperatures. The data show three independent dielectric processes: electrode polarization, hopping conductivity and interfacial polarization. The dielectric properties of humid insulating paper are composed of hopping conductivity and interfacial polarization, and its equivalent dielectric model can be represented by a Havriliak‐Negami (HN) relaxation branch parallel hopping conductivity. At high temperatures and low frequencies, the measured dielectric spectroscopy bends downward, which is caused by the electrode polarization. In this case, the equivalent dielectric model is composed of the body impedance of insulating paper and the electrode polarization in series. According to the equivalent dielectric model, the components of electrode polarization, hopping conductivity, and interface polarization can be separated, thereby eliminating the parasitic effect of electrode polarization on the dielectric properties of insulating paper. Both of hopping conductivity and interface polarization of insulating paper move toward high‐frequency direction with temperature increasing. For humid insulating paper with a moisture content of 5.9%, the activation energies of hopping conductivity and interface polarization are 1.18 and 0.99 eV, respectively. This difference in activation energies results in the inability of the spectrums of insulating paper to overlap with each other at different temperatures. Based on the insulating paper without oil immersion, the results obtained in this article are not affected by oil or oil‐immersion operations. This provides a reference for exploring the dielectric properties and physical mechanisms of oil‐paper composite insulation materials widely used in high‐voltage equipment. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Assessment of the aging of oil‐paper insulation is analyzed in this article, based on an improved fractional Poynting‐Thomson model, which includes dc and hopping conductivity (P‐T model2). Based on samples of oil paper produced in laboratories with different thermal aging times, it has been found that the proposed improved model provides a better fit and a higher index of coincidence concerning the measured values than the traditional P‐T model and the model that only incorporates the effect of dc conductivity (P‐T model1). Nevertheless, comparing the proposed improved P‐T model with the traditional Cole–Cole (C‐C), Davidson–Cole (D‐C), and Havriliak–Negami (H‐N) models, the improved P‐T model2 also demonstrated a superior fit for the measured value and a higher coincidence index than another model. In addition, there was an excellent exponential relationship between the quantities εa, εb and τ of the improved model and the furfural content of the samples. Consequently, these characteristic quantities could be utilized to estimate the furfural content in the oil‐paper insulation and evaluate the insulation's condition. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The partial discharge in the converter transformer will cause the carbonization of the insulating paper. The high concentration of free carbon particles generated from the insulating paper during the operation of the converter transformer will cause partial discharge, which will aggravate the insulation performance deterioration. For the bi‐directional interaction of carbon particles and partial discharge, the mechanism of insulating paper carbonization caused by partial discharge and the effect of carbon particles on the dielectric strength of oil paper are studied. In this paper, we construct a simulation system of amorphous cellulose to study the carbonization mechanism of insulating paper from the microscopic level. Furthermore, we build a DC voltage experimental platform to carry out partial discharge damage tests of oil‐paper insulation models and to measure the changes in the breakdown voltage with different carbon particle concentrations and diameters. The results show that partial discharge speeds up the cleavage rate of cellulose, generates low molecular hydrocarbon gas and water molecules, and the carbon atoms rearrange into PAH‐like molecules with aliphatic side chains. The surface of the insulating paper will carbonize, then form free carbon particles after peeling off. Afterward, the carbon particles in insulating oil accumulate in the high electric field area and attach to the insulating paper, which will cause electric field distortion and reduce the dielectric strength of oil‐paper insulation. With the increase of carbon particle concentration and diameter, the breakdown voltage of oil‐paper insulation decreases gradually. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Insulation aging of oiled paper is a common malfunction of transformers. It is of great value to recognize the insulation aging status of oiled paper and predict the service life of transformers using appropriate methods. In this study, an aging state recognition method based on partial discharge was proposed. Partial discharge signals were collected, the feature values were obtained through analysis of the principle component factor, and the state was identified by using a support vector machine. A Weibull distribution‐based method was proposed for the prediction of service life, and the residual life of transformers was determined using failure rate function. Through analysis, it was found that the fault analysis method had an accuracy rate of 80.55% in the recognition of the aging state, which was higher than that of Hidden Markov Model (HMM). In the case analysis, the accuracy rate of the method in recognizing the aging state of 100 transformers reached 82.06%. The accuracy of the failure rate function was also verified in the prediction of service life. This study provides some new ideas for the effective recognition of insulation aging of oiled paper in transformers and the prediction of service life. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

The transformer is a core device of the power system, and it is generally considered that the aging of insulating paper is important to the transformer. The aging process of insulating paper is the degradation process of cellulose. If it can be detected regularly, the aging of oil–paper insulating systems can be monitored conveniently. 5‐hydroxymethylfurfural is an important chemical substance produced by cellulose decomposition. It has broad prospects because of its many advantages. The oil–paper insulation system was thermally aged at 80, 90, 100, and 110 °C to measure the concentration of 5‐hydroxymethylfurfural on insulating paper and in transformer oil. In this paper, the concentration of 5‐hydroxymethylfurfural is detected by high‐performance liquid chromatography. The linear correlation coefficient of this method can reach 0.99, and the minimum detected concentration can be reduced to 10 µg/l. Experiments show that the concentration of 5‐hydroxymethylfurfural increases with the aging time, and when degree of polymerization (DP) decreased, the concentration of 5‐hydroxymethylfurfural increased. The correlation coefficient is greater than 0.92, which shows that there is an experimental relationship between the concentration of 5‐hydroxymethylfurfural and DP. The parameters of regression curves are different at different temperatures, but in actual operation, the temperature is low and remains stable. Therefore, 5‐hydroxymethylfurfural is expected to be a new indicator of the aging degree of oil–paper insulation system. © 2020 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

In the production of facial oil blotting papers, a certain number of papers must be counted before packaging. Currently, the papers are counted by hand, and this is hard work. Also, there are risks of adhesion of dust and wrinkles. In order to solve these problems, we propose a vision‐based approach. After the papers, which are arranged by shifting, are captured, the proposed image processing steps detect the boundaries of the papers. By counting the detected boundaries, the number of papers can be counted. Since the parameters for the proposed image processing are optimized by genetic algorithm, prior setting by a user is not necessary. For the experiments, an image dataset was constructed with six types of facial oil blotting papers. The proposed method achieved higher F‐measure than in other related works. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

Due to the compact and complex internal structure of 110 kV three‐phase enclosed GIS disconnector, the voltage distribution between the contact breaks of each phase has an influence on the insulation performance of the GIS disconnector, and its internal insulation design is a difficult point to be solved. To solve this problem, this paper firstly establishes a three‐dimensional model of three‐phase enclosed GIS disconnecting switch and conducts a research on the distribution of electric field under a specific working condition, it is found that the outer corner of the static contact, the inner corner of the static arc contact, the inner corner of the outer end of the moving contact and the inner corner of the moving contact are the internal electric field concentration of the three‐phase enclosed GIS disconnector. Then, in order to further reduce the electric field strength and improve the insulation margin and performance, this paper proposes a method based on the combination of Extreme Learning Machine (ELM) and Multi‐objective Grasshopper Optimization Algorithm (MOGOA) to optimize the structural design of three‐phase enclosed GIS disconnector, and a ELM model is established, which takes the internal fillet radius of stationary arcing contact, the internal fillet radius of moving contact, the internal fillet radius of external end of dynamic and static contact, the radius of the outer corner of the two static side contacts and the opening distance of the grounding contact as the inputs, and takes the maximum electric field strength of the two static side contacts and the moving side contacts as outputs; Finally, the structural parameters are optimized by MOGOA algorithm. Compared to the pre‐optimization period, the electric field strengths of the bus bar static‐side contact, dynamic contact and static side contact of the B‐phase after optimization decreased from 20.2, 9.28 and 17.5 to 11.4, 6.65 and 11.5 kV/mm, respectively. The electric field strengths of the dynamic and static side contacts are significantly reduced, which is beneficial for improving the insulation performance of the three‐phase enclosed GIS disconnector. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

To improve the pulse width modulation (PWM) harmonic suppression effect of the three‐phase VSI‐fed PMSM system, this paper proposed a novel random switching period (RSP)‐Space Vector Pulse Width Modulation (SVPWM) technique for the three‐phase power converter. First, the proposed technique replaces the 10‐bit linear feedback shift register pseudorandom number generator (LFSR‐PRNG) with a Tiny Mersenne Twister (MT)‐PRNG to quickly generate high‐quality pseudorandom number sequences. Then, to reduce the sampling error caused by the current ripple, this paper analyzes the sampling timing under different modulation techniques. Based on the interrupted update mechanism of the Infineon AURIX‐TC264, the variable frequency sampling of the RSP‐SVPWM technique is implemented to ensure the best sampling of the motor phase current. Finally, the simulation and experimental results show that the proposed technique can effectively disperse PWM harmonic energy. Meanwhile, the RSP‐SVPWM technique based on variable sampling frequency effectively improves the phase current quality of the PMSM system. The proposed technique shows great potential for suppressing PWM harmonics in integrated PMSM systems. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

This paper examines an inertial response control for wind turbines in order to provide the system inertia decreased by the integration of asynchronous variable renewable energy sources. Specifically, an application of the temporal power surge, a strategy by which the output of a wind turbine can be temporarily increased with releasing the kinetic energy stored in the rotating mass, was proposed to address significant frequency drops in a microgrid. Since the rotational speed of turbine has to be decreased by this approach, it is necessary to further reduce the wind power output to recover the rotational speed after the temporal power surge. This drawback may lead to a second frequency drop, and it is effective to intentionally increase the rotational speed beforehand to mitigate this negative effect. However, this measure causes output curtailment under normal operating conditions. Hence, a determination method of the rotational speed considering the output curtailment was proposed in this paper to facilitate frequency regulation through the temporal power surge. The proposed methods for adjusting rotational speed are evaluated and their effectiveness were verified through numerical simulations. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The increasing penetration rate of distributed energy brings more complex problems of voltage quality, safety and stability to the distribution network. A single optimal configuration of reactive power or energy storage is difficult to meet the increasingly diversified needs of modern power grids. This paper proposes a configuration strategy combining energy storage and reactive power to meet the needs of new energy distribution networks in terms of active power regulation and reactive power compensation, and to achieve tradeoff optimization in flexibility, voltage quality and economy, so as to adapt to the influence of new energy with different permeability. Firstly, the safety and stability evaluation system of distribution network is established with the target of flexibility demand and reactive power demand. Secondly, considering the coupling of planning layer and operation layer, a two‐layer model of energy‐reactive power optimization is established. After that, the gray wolf algorithm is used to solve the model, which enhances the global space exploration ability and reduces the possibility of falling into the local optimal. Finally, the improved IEEE33 node power distribution system is used for simulation test to verify the rationality and effectiveness of this scheme. The simulation results show that the scheme proposed in this paper can effectively improve the economy, security and stability of the distribution network, and can obtain an optimal configuration scheme with multi‐objective considerations under different new energy penetration rates. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

This paper presents a designed experimental simulation scheme for dynamic air gap eccentricity (DAGE) faults in permanent magnet synchronous generator (PMSG), along with the testing of their electromechanical characteristics. Unlike previous studies, this paper proposes and applies an experimental device setting scheme that enables accurate and convenient calibration of the DAGE fault degree, offering a novel solution for practical DAGE simulation. The experimental unit measures the electromechanical characteristics of the PMSG before and after the DAGE fault, taking into account the influence of load. The mechanical parameter considered is the stator vibration, while the electrical parameter is the circulating current parallel branches (CCPB) inside the stator winding. The characteristic frequencies of stator vibration and CCPB under the DAGE fault are analyzed based on the experimental results and verified through theoretical calculations and finite element analysis (FEA). The findings demonstrate the effectiveness of the proposed DAGE experimental device. Moreover, DAGE failure increases the strength of stator vibration and introduces new frequency components, namely fr and 2f ± fr. Under normal operation, the PMSG exhibits no CCPB. However, DAGE faults cause CCPB with frequency components of f ± fr. Moreover, the severity of the fault degree positively correlates with larger root‐mean‐square (RMS) values and characteristic frequency amplitudes of stator vibration and CCPB. Furthermore, the amplitude of stator vibration and CCPB decreases with increasing load. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Path planning is one of the fundamental issues in the research field of robot. In the last decades, Rapidly‐exploring Random Tree star (RRT*) was one of the chosen path planner for robot with its probabilistically complete. In this paper, an improved bidirectional RRT* path planner for robot is proposed (Bi‐RRT*), which has planned path with safety and smoothly guarantee. The main contributions of this paper include, firstly, combining the backtracking idea of the Quick‐RRT algorithm with the greedy search strategy of the RRT‐Connect algorithm, which can reduce the path cost and improve the operation efficiency of the algorithm. Second, in order to further reduce the running time of the algorithm, a new collision detection algorithm based on cross‐product is proposed to replace the conventional collision detection strategy. To ensure the quality of the path, two post‐processing strategies, path optimization strategy and path smoothing strategy, are proposed. Path optimization strategy is based on triangle inequality, and two optimization methods are proposed to effectively reduce the path cost. The path smoothing strategy based on the Bezier curve improves the continuity of a smooth arc and is better applied to path smoothing. Simulation results for both virtual and real environments show the advantages of combining Quick‐RRT and RRT‐Connect and verify the effectiveness of the proposed collision detection algorithm. Compared with similar algorithms, the proposed Bi‐RRT algorithm has higher operational efficiency, smaller path cost, smoother planned paths, and improved path quality. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

This paper proposes a control method for step voltage regulators (SVRs) to avoid voltage violations in distribution systems with unbalanced voltages due to photovoltaic (PV) generation and electric vehicle (EV) charging. Distribution system operators must effectively address voltage problems resulting from the widespread installation of distributed energy resources under the optimizing the utilization of existing voltage regulators to establish an efficient and rational infrastructure. Therefore, this study focused on advancements in voltage control using SVR based on line‐drop compensator (LDC) control, which is widely used in actual operations. We propose a method that utilizes voltage data from information technology switches to detect and address voltage unbalances in the control section, allowing for the sequential adjustment of the monitoring target in LDC control to maintain appropriate voltage limits under unbalanced conditions. We conducted power flow calculations using a distribution system model that represents an actual distribution system in the Hokuriku area. The effectiveness of the proposed method was evaluated in terms of its impact on PV and EV hosting capacity, as well as the frequency of tap operations. © 2023 The Authors. IEEJ Transactions on Electrical and Electronic Engineering published by Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The insulating gas and contacts in the arc extinguishing chamber of high‐voltage circuit breakers are the focus of research. In practical applications, the gas may react with the surface of the contacts. In this paper, C5F10O environmental friendly insulating gas, which has one of the potential alternatives, is selected as the research object. The compatibility of C5F10O and its decomposition products with CuW contacts was studied. This article uses the Dmol3 program based on density functional theory. The adsorption energy, transfer charge, and density of electronic states of C5F10O and selected typical decomposition products on the Cu (111) surface and Cu‐W surface were calculated, respectively. It was found that the original CuW metal properties were not changed before and after adsorption. The carbonyl O atom in C5F10O is easily adsorbed on the top of the Cu (111) surface, forming a stable CuO bond, which belongs to chemical adsorption. The interaction of the other three adsorption sites is weaker than that of the top site adsorption, which belongs to physical adsorption. C5F10O exhibits more active charge transfer and forms active W‐O chemical bonds when adsorbed on CuW surfaces than SF6. C5F10O has poorer compatibility with CuW alloy than SF6. C2F4 and C3F6 in the decomposition gas are chemically adsorbed on the Cu‐W surface. CO2, CF4, C2F6, and C3F8 do not form chemical bonds on the CuW surface. The adsorption stability of COF2 is weaker than that of CF4, C2F6, and C3F8. Compared with SF6 adsorption, the compatibility of C5F10O and CO2 on the surface of CuW contact is inferior to that of Cu contact. CF4, C2F6, C3F8, and COF2 in the decomposition gas can be compatible with the surface of the CuW contact. C2F4 and C3F6 cannot be well compatible with the surface of CuW contacts. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The eccentric harmonic magnetic gear (EHMG) has the characteristics of high torque density, high transmission ratio and high efficiency. The EHMG with Halbach array has better performance than the EHMG with traditional radial magnetization. Accurate calculation of its air‐gap magnetic field is of great significance for design and optimization. Based on the boundary perturbation method, a 2D analytical model of the air‐gap magnetic field of EHMG with Halbach array is established in this paper. The eccentric air‐gap magnetic field is calculated due to the permanent magnets of the eccentric rotor and the stator acting alone, and then the air‐gap magnetic field of the EHMG is obtained according to the superposition principle. The results of the air‐gap magnetic field are compared and evaluated by the regression evaluation indexes. The analytical results are consistent with the finite element results, which verifies the validity and accuracy of the analytical model. Comparing the EHMG with Halbach array and radial magnetization, the maximum static and dynamic electromagnetic torques of EHMG with Halbach array are increased by 59.1% and 55.6% compared with the EHMG with radial magnetization, which verifies the superior performance of EHMG with Halbach array. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Frequency‐domain electromagnetic (FDEM) instruments are effective tools for detecting underground electrical abnormal targets. However, due to the influence of various noises in the detection process, would lead to l poor signal‐to‐noise ratio of the system and would ultimately affect the detection accuracy. And FDEM detection systems have a defined measuring range. Excessive noise will lead to saturation of the system acquisition and distortion of the measurement. Because of the above problems, an acquisition technique for the FDEM receiving system is proposed to achieve noise suppression in the detection process. The scheme proposes a multi‐frequency LC filtering circuit to optimize the analog signal acquisition module of the receiver system. The circuit converts the measured voltage signal into a current signal, improving the system's immunity to interference. At the same time, the noise of non‐target frequencies in the measured signal is suppressed, avoiding saturation of the receiving system acquisition, and realizing high signal‐to‐noise acquisition of multiple target frequencies. First, the principle of circuit design is analyzed, and the design flow of circuit parameters is proposed. Further, the validity of the design is verified via simulation results. Finally, the optimization scheme is validated with an actual circuit. The results show that for the measurement environment set in this paper, this optimization scheme can suppress the noise of non‐target frequency in the measured signal, so that the noise amplitude can be reduced by more than 90%, and the signal‐to‐noise ratio of the filtered signal can be improved by 23.35 dB. This study helps to facilitate FDEM instruments to achieve high signal‐to‐noise ratio detection. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

It is important for university students studying elementary music education to master basic conducting gestures. We have developed a VR training system for self‐study of Saito's music conducting method. The system uses a depth camera and magnetic motion capture system to measure hand movements, and an HMD to superimpose the teacher's hand on the trainee's own hand. With the system, trainee can self‐study while visually and three‐dimensionally checking the motion and timing of the teacher's and the trainee's own hand gestures. In this paper, we describe an evaluation experiment with our system. The results showed that the VR environment is effective for learning three‐dimensional movements, and that the addition of a visual line display function for trajectories, a function to display trajectories from different viewpoints, and a replay function improves the learning effect. Specifically, the results of a short training session of 5 min revealed that the developed system was effective in bringing 75% of the trainees closer to the teacher's gesture. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

This paper proposes an energy management strategy (EMS) based on double‐deep Q‐Networks (DDQN) with demand torque prediction (DTP) to optimize the fuel consumption of hybrid electric vehicles (HEVs) by online utilizing vehicle‐to‐vehicle (V2V) information. The main framework of the EMS is designed as DDQN, combining Q‐learning with the deep neural network to realize real‐time training and online optimization of the torque distribution between the internal combustion engine and the electric motor, and given that the model training easily falls into local minima and overestimation, two different Q‐networks are designed to decouple action selection and target evaluation. Meanwhile, BP‐network predicts future demand torque using the ego vehicle speed, front vehicle speed, and distance between the two vehicles to reduce the burden of model training due to the introduction of traffic information. The predicted demand torque is introduced into the DDQN‐based EMS as states, together with the distance traveled in the driving cycle and the current information on HEV. The effectiveness and adaptability to actual driving cycles of the proposed strategy are verified by comparison with DDQN‐based EMS without DTP and rule‐based EMS. The results show that the fuel consumption using DDQN‐based EMS without DTP is reduced by 4.1% compared with rule‐based EMS. The introduction of demand torque prediction resulted in a further 3.9% reduction in fuel consumption. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In recent years, the amount of the photovoltaic (PV) system has been rapidly increasing from the viewpoint of carbon neutral. There are concerns about voltage rises and grid congestion in the electrical distribution network because of large‐scale PV increases. In order to address these issues, we focused on the control of water supply pumps in the water distribution system, which is infrastructure equipment for consumers. By controlling the start/stop of the water pump, it is expected to contribute to the power distribution system by increasing Demand Response (DR) and reduce CO2 emission from the electricity used by the pump. In this paper, with the aim of constructing an optimal operation planning method for water pumps that can evaluate DR and CO2 reduction effects, the optimal operation plan is formulated as a mixed integer linear programming problem. We numerical evaluated impact of water pump operation for CO2 emission and electrical distribution network. © 2023 The Authors. IEEJ Transactions on Electrical and Electronic Engineering published by Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Cogging torque can affect the performance of permanent magnet (PM) homopolar inductor machines (HIMs). In order to find the reduction methods of the PM HIM cogging torque, it is necessary to investigate its production mechanism and analytical model. In this paper, the production mechanism of the PM HIM cogging torque is revealed from the perspective of air‐gap field modulation principle. It is found that the air‐gap permeance of PM HIMs can modulate their air‐gap magneto‐motive force (MMF) and then a large number of modulated air‐gap magnetic fields are generated. These magnetic fields with identical production condition but different rotation speeds or rotation directions can interact with each other, hence the production of the PM HIM cogging torque. By the combination of energy method and air‐gap field modulation principle, the cogging torque analytical model of PM HIMs is derived. Based on the obtained analytical model, the methods for reducing the PM HIM cogging torque are further analyzed. Finally, a 48‐slot/4‐pole (48S4P) PM HIM is designed and exampled. The air‐gap flux density of the 48S4P PM HIM is simulated by three‐dimensional (3‐D) finite element analysis (FEA). Based on the harmonic analysis for the simulated results, the correctness of the proposed cogging torque production mechanism is validated. In addition, a prototype of the 48S4P PM HIM is manufactured. The cogging torque in the prototype is obtained by the analytical model, 3‐D FEA and experiments, respectively. The simulation and measurement results verify the correctness of the cogging torque analytical model. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

This paper concerns the bipartite consensus problems of directed cooperative and antagonistic networks (CANs) with time‐varying communication delays. A distributed control protocol is proposed based on the nearest neighbor rule. In order to derive the convergence analysis of the proposed protocol, a model transformation is introduced, based on which the consensus can be equivalently transformed into the asymptotic stability of a reduced‐order system. Besides, the sufficient conditions are provided to ensure the bipartite consensus (respectively, state stability) of CANs whose topologies are structurally balanced (respectively, unbalanced). In addition, numerical examples are given to illustrate the effectiveness of our developed results. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Rear‐lamp tracking at night is a research topic in night vision that is essential for Advanced Driver Assistance Systems (ADAS). Most current computer vision‐based methods address this problem using color features because rear lamps are lit during night driving. However, such methods are sufficiently robust in complex environments owing to the lack of feature diversity. On the other hand, as there is no off‐the‐shelf dataset, the application of deep learning to nighttime rear‐lamp tracking has been sparsely explored. To tackle the above issues, in this paper, we propose hierarchical rear‐lamp tracking at nighttime (H‐RTN) and create a novel dataset for rear‐lamp tracking. Specifically, the H‐RTN consists of a rough detection hierarchy (R‐hierarchy), an accurate detection hierarchy (A‐hierarchy), and an optimization hierarchy (O‐hierarchy). The R‐hierarchy determines the region of interest (ROI) containing the target rear lamps, the A‐hierarchy samples the rear‐lamp candidates in the ROI, and the O‐hierarchy selects the best pair of candidates as the final location of the target rear lamps. The experimental results show that H‐RTN outperforms the alternative existing methods. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Many recent sequential recommendation methods have aimed to enhance the modeling of users' diverse interests to provide more accurate and varied recommendations. Despite great success, existing models possess a limitation in their capacity to solely perceive items within a user behavior sequence. Such an approach may potentially constrain their ability to effectively discover users' multiple interests. In this paper, we present a novel approach that addresses this gap by harnessing global item transitions to uncover users' potential interests, subsequently modeling them as local subsequences. To achieve this objective, we represent global item transitions as a directed graph, constructed by amalgamating behavior sequences from the training set. This graph‐based representation allows the design of a specialized module capable of aggregating global item transitional information and uncovering local subsequences specific to individual users. Consequently, downstream sequence models can focus on pertinent item transitions, disregarding unrelated ones. We evaluate the effectiveness of our method on four public data sets, outperforming existing alternatives or delivering competitive results. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Active disturbance rejection control (ADRC) has been widely used in the permanent magnet linear synchronous motor (PMLSM) drive system for its strong anti‐disturbance ability and fast response speed. However, a large number of adjustment parameters add difficulties to its application. To solve this problem, a novel sliding mode‐based active disturbance rejection control (SM‐ADRC) with autotuned parameters is proposed in this paper. In this control strategy, the SM is incorporated with extended state observer (ESO) and nonlinear state error feedback (NLSEF) to reduce the number of adjustment parameters. The simulated annealing particle swarm optimization (SAPSO) algorithm is carried out to achieve the optimal configuration and realize parameter self‐tuning. The experimental results of the PMLSM speed servo system demonstrate the proposed control method has better suppression of chattering effect, disturbance rejection ability and fast dynamic response. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Object tracking tasks often face problems such as illumination and appearance changes due to various scenarios. To effectively solve such problems, single object tracking algorithms in recent years have improved the stability of the tracker by introducing online learning, reducing tracking drift, and tracking objects stably even with large deformations. However, on the one hand, employing online learning increases computation costs, causing the tracker to run slower. On the other hand, because it learns from the tracking results, the tracking template will only be correctly updated if the object is accurately tracked. Any incorrect update will result in tracking failure. In this paper, we propose a filtering algorithm for online learning sample processing in object tracking to remedy these issues. Our method can select valid training samples and discard unnecessary training samples in object tracking. Numerous experiments demonstrate that our algorithm improves the tracking accuracy, reduces the computation complexity, and improves the running speed and run‐time. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In order to decrease the reradiation interference (RRI) of power transmission lines, aiming at the defects that the existing RRI suppression methods cannot be applied to the constructed power transmission lines, and cannot suppress all the RRI extreme values in the frequency band, this paper innovatively proposes a RRI suppression method based on characteristic mode (CM) theory. Firstly, we briefly introduce the CM theory and decompose the total scattering field into the superposition of the characteristic electric fields; secondly, the influence of inductance and capacitance characteristics of the reactive loads on radiation behavior of the CMs is analyzed, and the ideal position for reactive loading is also discussed to reduce the contribution of CM to the total RRI; finally, a simulation experiment is carried out in AM broadcasting band, and the modal weighting coefficients of main CMs affecting the RRI is greatly reduced in the frequency band by reactive loading. Simulation results show that compared with the existing method, the proposed method can reduce the peak value of RRI by 43.9% and the overall RRI by 29.7%. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Replicating specific scents by mixing 'base odors' is the main idea behind the concept of odor reproduction. Just as primary colors can be combined to generate a wide range of colors in visual perception, the hope is to find a similar principle in olfaction. However, defining such 'primary odors' is difficult due to the complexity of our sense of smell, which is much different from vision. In spite of these challenges, numerous scientists have endeavored to identify a combination of basic smell components that can mimic various scents. Currently, the suggested combinations of smell components are typically only successful at recreating specific, intended scents. The range of reproducible scents differs based on the selection of base odors, yet these studies have provided valuable knowledge about the nature of these primary odors. This review paper will focus on the latest studies related to odor reproduction. Understanding odor space, odor reproduction, and the challenges encountered when expanding the range of odors will be explained. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Energy internet zones (EIZ) supply multiple energy carriers to customers in certain regions. They can achieve high energy efficiency by energy cascade utilization. In mid‐term, they participate in the wholesale market and retail market simultaneously. Customers can shift their energy use among different hours and energy carriers to satisfy demand according to the retail prices. Unfortunately, multiple energy systems and markets bring various uncertainties on demand and prices. In this paper, the weekly bidding strategy for the EIZ is proposed to determine the optimal bilateral contracts to sign and the optimal energy retail prices. In retail market, the satisfaction degree and elasticity matrix describe customers' response. Distributionally robust optimization is adopted to consider the distributional uncertainties of random variables and Worst‐case Conditional Value‐at‐Risk is employed for risk management. The distributional uncertainties of pool prices and elasticity matrix are discussed in this paper. An EIZ in Shanghai, China is adopted to illustrate the proposed strategy. The results have great resistance to distributional uncertainties. The risk aversion and satisfaction degree affect the EIZ's strategy in wholesale market and retail market, respectively. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Power line insulator defect identification usually suffers from complex backgrounds, small defect target sizes, and inconspicuous defect features. Traditional identification methods based on image processing, image analysis, and pattern classification have many limitations in solving the aforementioned problems. In recent decades, deep learning classification methods have gradually replaced traditional identification methods in the task of power line insulator defect identification. To accurately identify the locations of insulator defects, this paper proposes an insulator defect detection algorithm using an improved lightweight YOLOv4‐tiny network (ILYTN). First, the CBL (Conv‐BN‐LeakyReLU) modules of the backbone network are replaced with MobileViT blocks to enhance the feature extraction capability of the backbone network. Second, coordinate attention (CA) is introduced in the feature fusion part to improve the network's ability to focus on the location of defects. Finally, an EIOU (efficient intersection over union) loss function, instead of the original CIOU loss function, is used so that the convergence speed of the network can be improved. To verify the effectiveness of the proposed algorithm in this paper, the mViT‐yolo algorithm is compared with the mainstream Faster‐RCNN algorithm, SSD algorithm, YOLOv3 algorithm, and YOLOv4‐tiny algorithm. The experimental results show that the algorithm proposed in this paper outperforms all the above algorithms in terms of detection accuracy. Compared with the traditional YOLOv4‐tiny algorithm, the proposed algorithm increases the mean average precision (mAP) by 1.64%, the average precision (AP) of missing insulator defects by 0.32%, and the average precision (AP) of broken insulator defects by 4.96%. © 2023 The Authors. IEEJ Transactions on Electrical and Electronic Engineering published by Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The grid‐forming converter (GFC) is used to regulate the voltage and frequency of a local grid. However, due to the limited current capacity, the GFC must actively modify its control strategy when a serious external fault occurs, thus to avoid the possible damage caused by overcurrent. This paper proposes a novel voltage reference generation method for GFC based on the external equivalent impedance magnitude (EEIM), which has the following merits: (i) the faulty phase currents and the non‐faulty phase voltage can be controlled within their operational limits. (ii) The voltage reference unbalance factor (VRUF) of the GFC can be adjusted flexibly if necessary. Then, in order to achieve the optimal support effect for the faulty phase voltages, a two‐stage GFC fault control strategy is proposed in this paper. In the first stage, the fault type is judged by computing and comparing the EEIM of each phase. In the second stage, the voltage reference mode is determined according to the fault type, and the VRUF is adjusted to its optimum value through a search algorithm. Simulation results based on Matlab/Simulink verify the effectiveness of the proposed GFC fault control strategy in terms of current limiting and faulty phase voltage support. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

It is of great importance to build an accurate model for the multi‐step forecasting of household power consumption. In recent years, more and more researchers have focused on adopting hybrid models to execute forecasting due to the irregularity and nonlinearity of power data. However, existing forecasting models usually make predictions directly on original data. This paper introduces secondary decomposition algorithm used to decompose primal data. We use singular spectrum analysis (SSA) to decompose the original series into several subseries, utilize variational mode decomposition (VMD) optimized by whale optimization algorithm to decompose the subseries with the highest frequency into several intrinsic mode functions. Then all subseries obtained from SSA and VMD are fed into long short‐term memory model to get predictions. In order to confirm the validity of proposed model, this paper performs several experimental analyses. The results of experiments show that the proposed model effectively improves the accuracy of forecasting. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In this letter, a disposable micropower source was developed by integrating a microbial fuel cell (MFC) in filter paper. The paper‐based MFC could harvest electrical energy generated by Escherichia coli during the metabolic process. The air‐dried biofilm anode was activated by water for on‐demand electricity generation. This study aimed to optimize the anodic and cathodic materials for maximization of the MFC performance. The concentration of activated carbon powder in the anode and potassium ferricyanide in the cathode were optimized. The paper‐based MFC with the optimum anode and cathode generated a maximum power density of 8.4 µW/cm2. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

Frequency response analysis (FRA) method has been widely used in the world, but the interpretation of its signatures is still a hard problem to solve. This paper introduces a method of the sum of two‐way shortest distance for transformer winding deformation fault diagnosis, which is based on trajectory similarity between FRA signatures. Compared with most existing methods, it does not need order preservation; however, it focuses more on the trajectory itself. The geometric principle of the sum of two‐way shortest distance is introduced and analyzed in detail. By using the circuit analysis software, the equivalent circuit model of the transformer is established, a group of the FRA signatures of three types of transformer winding fault, including axial displacement, radial deformation, and disk space variation fault, are obtained. The distribution of different type of faults is studied by using the sum of two‐way shortest distance to process the FRA signatures in three different frequency bands. Using the sum of two‐way shortest distance as input, the support vector machine (SVM) is employed to train a predictive engine for transformer winding deformation fault diagnosis. Result shows that the proposed method can well classify and diagnose transformer winding deformation fault. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In an electric power system with a large number of renewable energy sources such as wind farms (WFs), the WF's output would be curtailed in order to maintain the supply–demand balance when it is predicted that there would be excess power generation in the entire system. In this case, it is important to ensure fairness among WFs from the viewpoint of the curtailed outputs and to minimize the total of the curtailed power. In this paper, we propose a measure to simultaneously achieve a reduction in curtailed power and a fair upper limit using demand response. The validity of the proposed measures is confirmed by numerical calculations. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In this paper, an online compensation predictive control method based on hybrid torque sharing function (HTSF) is proposed to reduce current spikes in the torque sharing control of switched reluctance motor (SRM). First, predictive control is introduced to the torque sharing function (TSF) and a new cost function is designed with Laplace multiplier method by predicting the current and torque of the next cycle of SRM. Then the optimal current control amount is carried out. Second, the ratio of the torque error to the desired torque and its derivative are compensated online to the current phase at the beginning of the commutation overlap period to accurately track the torque, and the torque distribution is optimized by a HTSF at the end of the phase change to further reduce the current spikes and suppress the torque ripple. Finally, the experiment on 8/6 four‐phase SRM is achieved to verify the feasibility and effectiveness of the proposed control strategy, and the results show that the current spikes and the torque ripple are reduced by 25% and 14.5% respectively. Therefore, compared with traditional TSF control, this method can effectively reduce the SRM torque ripple and excessive current spikes. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

To enhance the stability of power system, a power system stabilizer (PSS) is one of the control mechanisms installed in the power plants. A suitable PSS parameters set can help in reducing the power swing. In general, the design of PSS parameters is performed based on a nominal operating condition of the power system. In this paper, a multi‐objective optimization algorithm based on pole placement technique is proposed to find a robust PSS parameters set. The proposed strategy searches for the optimal PSS parameters under multiple operating conditions of the generator. Preliminary simulation results on a single machine infinite bus (SMIB) model show that the proposed PSS parameters design method can further improve the robustness of the overall power systems performance under different types of disturbance. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In this paper, a novel differential dual‐rotor contra‐rotating axial‐flux PM (DDC‐AFPM) motor with equidirectional toroidal winding (EDTW) applied to electric propulsion of ships is proposed. Different from the conventional AFPM motor with contra‐rotating rotors (CR), the rotors of the proposed motor on both sides of the stator rotate oppositely at different speeds. The structure of the proposed motor is introduced and the operation principle is clarified. Initial parameters of the proposed motor are given, and the correctness of the simulation results is indirectly verified through the prototype of the AFPM motor with dual‐rotor and EDTW. In order to further improve the electromagnetic performance of the proposed motor, parameters of the motor are preliminarily improved. Finally, the electromagnetic characteristics including armature field, no‐load and on‐load characteristics of the proposed motor are analyzed based on three‐dimensional finite element method (3D‐FEM). The simulation results show that the proposed motor has good electromagnetic characteristics and is suitable for ship propulsion. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The long‐stroke electromagnetic repulsion mechanism is subjected to large stresses during the driving phase, and the repulsion disc is prone to fracture due to excessive vibration amplitude up and down. Therefore, it is necessary to reduce the peak stress and vibration amplitude of the repulsion disc, improve the mechanical life, and improve the driving performance without decreasing the motion displacement, but it is not possible to do so at present. To address this problem, this paper takes the 'coil‐repulsion disc type' electromagnetic repulsion mechanism as the research object, and builds a simulation model of electromagnetic repulsion mechanism with structural strength and driving performance by using finite element simulation software, and analyzes the effects of four structural parameters, namely, the height of the repulsion disc, the inner diameter of the repulsion disc, the radius of the circular table and the radius of the chamfer, on the displacement and stress distribution of the model. After that, 39 sets of samples were output by BBD experimental design method, which were introduced into the BP neural network prediction model and combined with NSGA‐II algorithm to optimize the structure of the electromagnetic repulsion mechanism. The simulation results show that with the repulsion disc height of 14 mm, the repulsion disc inner diameter of 14 mm, the radius of the circular table is 29.78 mm and the chamfer radius of 7.06 mm, the peak stress of the repulsion disc of the electromagnetic repulsion mechanism is reduced by 57.83%, the amplitude of the repulsion disc is reduced by 3.24 mm, the peak electromagnetic repulsion force is increased by 7.52 kN and speed at the end of 3 ms increased by 9.8%. Under the condition of satisfying the constraints and increasing the overall displacement, the structural strength is increased and the driving performance of the mechanism is ensured to be improved, providing reasonable mechanism parameters for the opening and closing requirements of the fast mechanical switch. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

With the increase of nonlinear loads (such as electric arc furnace, electrified railway, etc.) in power system, the harmonic distortion and unbalance of voltage and current are becoming more and more serious. The energy flow in the system is more complex and variable, and the power factor calculation method is controversial. This paper summarizes the influence factors and calculation methods of power factor for nonsinusoidal and unbalanced systems. The calculation methods of arithmetic power factor, vector power factor and effective power factor are compared first, and then the power factor calculation method recommended by IEEE Std 1459‐2010 and its improvement method under three‐phase balance user, active power calculation and metering error are analyzed, and the recommended calculation methods for different situations are given. Finally, future research perspectives and challenges for power factor calculation are pointed out. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

This paper was arranged a polymer cylinder around a Cu fuse‐element to increase both an arc resistance rarc$$ {r}_{\mathrm{arc}} $$ during a DC arc quenching process and an insulation resistance Rins$$ {R}_{\mathrm{ins}} $$ after the DC arc quenching. The used polymer cylinder equips a narrow‐section with a width wP$$ {w}_{\mathrm{P}} $$ made from the polymer. A position of the narrow‐section was around an arc‐ignition point of the Cu fuse‐element. Silica‐sand (SiO2‐sand) was filled inside the polymer cylinder. Then, a damping DC with a prospective peak of 1000 A was energized to the Cu fuse‐element. As an experimental result, rarc$$ {r}_{\mathrm{arc}} $$ was successfully increased with wP$$ {w}_{\mathrm{P}} $$ of the narrow‐section. In addition, the rise in wP$$ {w}_{\mathrm{P}} $$ of the narrow‐section also increased Rins$$ {R}_{\mathrm{ins}} $$ to more than 10 MΩ$$ \mathrm{M}\Omega $$ under the DC 1000 V application after the arc quenching. In order to interpret rarc$$ {r}_{\mathrm{arc}} $$ rise and high Rins$$ {R}_{\mathrm{ins}} $$ under the polymer cylinder arrangement, chemical composition, an electrical resistivity ρ$$ \rho $$, and a thermal diffusivity α$$ \alpha $$ of Cu/SiO2/Polymer vapor mixture was also calculated. Based on the experimental result and calculation result, rarc$$ {r}_{\mathrm{arc}} $$ rise can be interpreted based on rise in ρ$$ \rho $$ and α$$ \alpha $$ due to the polymer vapor admixing into Cu/SiO2 vapor mixture. In addition, increasing Rins$$ {R}_{\mathrm{ins}} $$ can also be interpreted by the polymer ablation of the narrow‐section of the cylinder. The results are useful to further increase the interruption capacity of the DC fuse. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Aiming at the problem of difficulties in heat dissipation for a permanent magnet synchronous motor (PMSM) with high power/torque density, the effect of motor length‐to‐diameter ratio (r0) on the selection of cooling water channels is investigated from the perspective of the geometric parameters of the PMSM in this paper. First, the 3‐D fluid–solid coupled heat transfer models of three actual motors with the length‐to‐diameter ratios of 0.27, 0.81 and 2.04 are established. Every model is calculated under spiral, axial and circumferential cooling water channels, respectively. The cooling effect, cooling energy loss and motor thermal balance are compared and analyzed. Then the optimal cooling water channel for each of three motors is confirmed. Further, the motor temperature rise and fluid differential pressure are plotted. The threshold of motor length‐to‐diameter ratios is determined at which the overall performance of the axial and circumferential cooling water channel is highly similar. The general conclusions of selection of cooling water channels for PMSMs with different geometry shape are summarized. Finally, a prototype with r0 = 0.27 is fabricated and tested, verifying the validity of the fluid–solid coupling simulation analysis. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The five‐phase induction motor, being the most elementary form of multiphase induction motors, boasts low noise, low torque fluctuations, and high load‐bearing capacity, and is hence suitably employed in domains where high power and reliability are required. In light of the susceptibility of the speed encoder to interference from external environments, this paper proposes a sensorless vector control technique for the five‐phase induction motor based on a speed‐adaptive full‐order observer. The proposed approach first employs the nearest four‐vector space vector pulse width modulation (NFV‐SVPWM) as the modulation technique for the five‐phase inverter, in order to provide a constant switching frequency and low harmonic losses. Subsequently, the expression for the speed‐adaptive full‐order observer is constructed based on the mathematical model of the fundamental space of the five‐phase induction motor, and the expression for the adaptive speed law is deduced using the Lyapunov function. Additionally, the bilinear transformation method is utilized as the discretization technique for the full‐order observer during the process of digital implementation, in order to achieve higher discrete accuracy. Finally, an experimental study involving a 4.5 kW five‐phase induction motor was conducted to validate the accuracy and effectiveness of the proposed method. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The commonly used DC coil wounded around the electromagnet winding skeleton, acts as the key electro‐magnetic conversion element, is formed by enameled wire with poor heat dissipation. The electric conductivity of the conductors will be greatly influenced by the high temperature generated from coil's internal heat, especially for long‐term work conditions. Thus, in order to calculate the DC coil's temperature accurately and effectively during the primary design process of the electromagnet, a novel temperature rise calculation method for the steady and transient is proposed in this paper. First, the geometric and resistance models of the enameled wire are established, according to the spatial arrangement and the resistance‐temperature characteristics. Secondly, the temperature rise of the electromagnet coil is calculated theoretically, based on the steady and transient heat dissipation equations. Thirdly, the Thermal‐Electric simulation model is established, which is used to simulate and analyze the temperature of the electromagnet coil changing with excitation voltage. Finally, a temperature rise test platform of the electromagnet coil is established, the steady and transient temperature rise under various conditions is measured. The temperature rise results of theoretical calculation, simulation and experiment show good agreement with each other. It gives significant guidelines to the design and optimization processes of such electromagnet DC coil. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In this paper, we compare air‐conducted (AC) speech with bone‐conducted (BC) speech for the purpose of utilizing them in packet loss concealment (PLC) for speech quality of voice over internet protocol (VoIP). Instead of the autocorrelation method of linear prediction (LP), which was utilized in the conventional PLC techniques, we employ the modified covariance (MC) method. The MC method provides accurate LP estimation from short input data samples and avoids the numerical problem the autocorrelation method suffers from. The lost frame is compensated from both forward and backward directions in which linear gain and weighting are applied. When BC speech is used as the input speech data for PLC in the case where the speech sender is in noisy environments, BC speech behaves more accurately than the corresponding AC speech, resulting in an excellent performance of the LP‐based PLC technique. This unveils a useful use of BC speech in speech information systems. Experiments show that in severe noise environments of AC speech‐to‐noise ratio being less than 10 dB, BC speech is superior to AC speech for PLC. It is also shown that the transmitted BC speech is more accurately reconstructed for PLC than transmitted AC speech is done. © 2023 The Authors. IEEJ Transactions on Electrical and Electronic Engineering published by Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In Hokuriku area, where lightning strikes with a large amount of electric charge occur in winter, failure rate of lightning protection devices such as surge arresters and devices with built‐in zinc oxide (ZnO) elements tends to be high. In order to prevent failure of surge arresters, 5 kA surge arresters which have a larger energy capability are installed on terminal poles of distribution lines. As for lightning protection of pole‐mounted distribution transformers, insulators with ZnO are utilized to support medium‐voltage drop wires connected to the transformers on non‐terminal poles. In this paper, we have studied the effect of insulators with 5 kA ZnO which have a larger energy capability as a lightning protection measure for transformers on terminal poles using lightning‐surge analysis. The lightning outage rate, which is the total of insulation breakdown rate and failure rate of a lightning protection device, is found to be lower in the case of insulators with 5 kA ZnO than in the case of 5 kA surge arresters. In addition, by replacing 5 kA surge arresters with insulators with 5 kA ZnO, a cost reduction effect is found to be also expected. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Along with the commercialization of SiC‐MOSFETs and progress in the development of GaN power devices, high‐speed, high‐frequency switching and reduction in conduction loss of power devices are expected. Hence reduction of the size and increase of conversion efficiency of power electronics equipment is greatly expected. On the other hand, even if power devices are switched at high speed and high frequency, the loss of passive devices such as transformers, inductors, and capacitors used in power converters increases, making it difficult to make the power converters smaller than expected. In other words, there is a demand for performance improvements of passive devices from various viewpoints, including miniaturization and low loss, which are compatible with high‐speed, high‐frequency switching operations of power devices. This paper introduces recent research results on loss evaluation methods considering the operating state of passive devices used in small‐to‐medium‐capacity power converters those perform high‐frequency switching operations. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Dissolved gas in transformer oil (DGA) online monitoring data can reflect equipment insulation performance, which provides an important basis for transformer condition assessment. The accuracy of online monitoring data directly affects the correctness of transformer condition assessment, and the health condition of the online monitoring data device also affects the effectiveness and reasonableness of online monitoring data. With the accumulation of operation time, the DGA online monitoring device faces many problems, resulting in the overall deviation of this indicator data from the actual value, and the transformer online monitoring device cannot play its monitoring effect. To solve these problems, this paper firstly linearizes the data of the DGA online monitoring device by segmentation, extracts the characteristics of the line segment curve, constructs a segmented correlation mining model, and mines the correlation of different indicators of DGA. Then, according to the change of correlation strength and weakness between online monitoring data in time sequence, the data deviation is tracked. Finally, a multi‐indicator back propagation (BP) neural network algorithm optimized by the genetic simulated annealing algorithm is constructed to calibrate the deviated data. The analysis shows that the method can identify the population deviation of online monitoring data and calibrate the deviated data effectively. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In orthogonal frequency division multiple access (OFDMA) systems, carrier frequency offsets (CFOs) influence the different users. In this paper, we proposed a CFO estimation algorithm with strong interference resistant capability for OFDMA systems. The first part of the proposed algorithm processes the received signals so as to deal with the CFO estimation problem. And the second part of the proposed algorithm is to use the proposed adaptive process to obtain the updated CFO estimation and track the parameters' time‐variations. Simulations demonstrate the effectiveness of this method and show that its performance is to the Cramer‐Rao Bounds (CRB). © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

This paper investigates the influence of the loss distribution and magnetic saturation on the efficiency performance, which includes the location of maximum efficiency point, the size of high‐efficiency region and the value of maximum efficiency, for an interior permanent magnet synchronous motor (IPMSM). The loss expressions considering magnetic saturation are first proposed and then the efficiency‐losses function model of the IPMSM is constructed. The efficiency performance of the motor is analyzed quantitatively. The general principle is summarized including adjusting the location of maximum efficiency point, expanding the size of high‐efficiency zone and improving the maximum value of efficiency from the perspective of loss distribution and magnetic saturation. Two IPMSMs with different magnetic circuit characteristics are designed to verify the correctness of the analytical method by finite‐element analysis (FEA). Finally, prototypes are manufactured for the experiment and measurement results are given for validations. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In order to reduce the clock offset caused by network delay jitter, network asymmetry, clock drift and clock frequency difference in the clock synchronization process of IEEE1588, a modified Strong Tracking Adaptive Kalman Filter (MSTAKF) algorithm was proposed. The Kalman filter model established by the algorithm is based on clock offset, network delay, frequency deviation and asymmetry ratio. The filter includes the modified strong tracking algorithm based on fuzzy logic and hypothesis test proposed in this paper, which can effectively eliminate the influence of outliers, and finally make the model tracking effect better. In addition, the modified Sage‐Husa algorithm based on Cholesky decomposition is also included, which makes the measurement noise more stable and ensures the positivity of the measurement noise covariance. The experimental results show that the proposed MSTAKF is smoother than Karman filter (KF), Sage‐Husa adaptive Kalman filter (AKF) and strong tracking Sage‐Husa adaptive Kalman filter (STAKF). Compared with these filter algorithms after testing in the LAN environment, the precision improvement and accuracy rate are significantly improved. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]