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Objective Contactless power supply method, leveraging the advantages of no direct electrical contact between the primary and secondary side coils, is currently being explored in the rail transit industry. The high-power, high-frequency application scenarios pose challenges in the design of the contactless traction power supply system, component selection, and coupling mechanism design. It requires optimization of the design scheme and system efficiency. Method For rail transit application scenarios, the system structure of a contactless traction power supply system based on the LCC-S (inductance-capacitor-capacitor-series) compensation topology is introduced. A 250 kW contactless power supply system is designed, utilizing double D-shaped coils for the primary track coils and secondary receiving coils. The impact of factors such as mutual inductance of coupling coils and losses in magnetic materials on system efficiency is studied. System circuit model and coupling coil model are established. The system is simulated based on the model, and parameters for the magnetic core thickness in different regions of the secondary coils are optimized. An experimental platform for contactless traction power supply system is built, and tests are conducted at a power level of 250 kW to validate the effectiveness of the design optimization method. Result & Conclusion The simulation and experimental results confirm the effectiveness and feasibility of the design optimization method. Optimization of the core layout ensures coil mutual inductance and reduces core losses. The system demonstrates the capability of delivering a rated output power of 250 kW. Under air gap heights of 70 mm and 80 mm, the static and dynamic operating efficiencies of the system are both greater than 90%.

The increasing popularity of electric drives employing an isolated dual-inverter (DI) topology is motivated by their superior DC-link voltage and power utilization, fault-tolerant operation, and potential for multilevel operation. These attributes are significant in battery-powered transportation, such as electric vehicles and aviation. Given the considerable freedom in modulation and control of the DI topology, this paper researches the impact of reference voltage vector distribution between the two individual inverters. The study also evaluates the influence of two well-established asynchronous modulation strategies—Space Vector PWM (SVPWM) and Depenbrock's Discontinuous Modulation (DPWM1). Since simulation tools nowadays play a crucial role in power electronics design and concept verification, the results are based on extensive and detailed models in Matlab/Simulink. Employing the basic field-oriented control of a 12 kW induction motor with precisely parameterized SiC switching devices for accurate loss calculation, this research reveals the possibility of significant energy savings at multiple operating points. Notably, optimal efficiency is achieved when one inverter operates up to half of the nominal speed while the other solely establishes a neutral point for the winding. Moreover, the results highlight DPWM1 as a superior strategy for the DI topology, showcasing reduced converter losses. Overall, it is shown that the system's losses can be significantly reduced just by the design of the voltage vector distribution in the drive's operating range and the modulation strategy selection. [ABSTRACT FROM AUTHOR]

In this paper, a control method combined with variable frequency and phase shifting is proposed, the primary purpose of which is to optimize the operating efficiency of the phase‐shift full‐bridge (PSFB) DC‐DC converter. By modeling the losses of the PSFB converter, the optimal switching frequency related to the load conditions is found. A neural network aided variable frequency controller that can work linearly is built to achieve the proposed method. At the same time, the voltage control loop is retained to ensure the stability of the output voltage and the necessary dynamic response of the converter. This paper builds an experimental platform for a 2 kW PSFB DC‐DC converter to verify the effectiveness of the proposed control method. With the control method proposed in this paper, the PSFB converter can always work at the optimum efficiency point under different load conditions. In addition, this paper also analyzes the influence of variable frequency control on PSFB operating states, such as zero‐voltage‐switching (ZVS) constraints, continuous conduction mode (CCM) operating states, and power density, which have an impact on its operating conditions. [ABSTRACT FROM AUTHOR]

In today's dynamic and complex global business landscape, effective supply chain network (SCN) management is critical for achieving competitive advantage and sustainability. This study presents an innovative methodology that leverages the fuzzy CRITIC (CRiteria Importance Through Intercriteria Correlation) and EDAS (Evaluation based on Distance from Average Solution) techniques to enhance the efficiency of SCNs. By integrating both quantitative and qualitative factors, the approach effectively navigates uncertainties and imprecise data in supply chain operations. The fuzzy CRITIC-EDAS method's application in a case study showcases its utility in optimizing SCN configurations for improved efficiency, cost savings, and risk reduction. The results offer a valuable decision support tool for supply chain management, promising to boost competitiveness and sustainability in an unpredictable market. [ABSTRACT FROM AUTHOR]

Efficient sugarcane production is crucial in today’s competitive agricultural landscape. Traditional planting methods are cost-intensive and time-consuming and often fail to achieve adequate compression of buds due to the stalk planting nature of sugarcane. To address these challenges, a novel approach using machine vision to identify and plant sugarcane nodes is proposed. Sugarcane holds significant economic importance in India and various other countries, making its cultivation a cornerstone of many economies. The development of a sugarcane node cutting machine aims to revolutionize the process of preparing sugarcane seedlings. This machine streamlines the time-consuming task of cutting nodes, thereby reducing waste and effort associated with traditional methods. The paper focuses on designing and testing a machine for efficiently cutting sugarcane buds, intending to mechanize the preparation stage of sugarcane seedlings. By cutting undamaged bud-containing sugarcane stalks, this machine eliminates the need for laborious manual cutting, providing a timesaving and cost-effective solution for farmers. Furthermore, by measuring cutting force and power requirements, the research aimed to optimize the efficiency of sugarcane cutting processes. [ABSTRACT FROM AUTHOR]

Based on the rigorous nonlinear theory of relativistic traveling wave tubes (TWTs) and backward wave oscillators BWOs on irregular hollow waveguides with cathode filter-modulators, taking into account both propagating and supercritical waves, taking into account losses in the walls of the waveguide and the inhomogeneity of the magnetostatic field guiding the electron flow, the influence of dynamic stratification of the electron flow on the efficiency of the generator is determined. The article shows a full compensation possibility on the influence of dynamic layering on efficiency by optimizing an electronic beam in inhomogeneous high frequency and magnetic fields and the corrugated irregular waveguide characteristics when electron beam layers depositing on it. [ABSTRACT FROM AUTHOR]

Copyright of Electric Power Automation Equipment / Dianli Zidonghua Shebei is the property of Electric Power Automation Equipment Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, the proposal for the performance optimization of the wireless power transfer (WPT) system is given. The solution is based on the alternative configuration of the secondary-side rectifier. It is represented by a diode rectifier with a current doubler. Compared to the bridge rectifier, two diodes are replaced by the inductors. Initially, a system analysis was performed to investigate the electrical behavior and find the most optimal conditions referred to as terms of efficiency performance at nominal power. Due to this requirement, the rectifier inductors must be designed accordingly to meet this condition. The experimental verification was realized as well, while the proposed solution was compared to other common alternatives of the secondary-side rectification. The load sensitivity analysis in terms of efficiency performance was realized as well to observe the system behavior for a wide operation range. From the results, it is seen that the proposed alternative of the secondary-side rectification of the WPT system gives promising results in terms of high operating efficiency. [ABSTRACT FROM AUTHOR]

Six-degrees of freedom (6-DOF) parallel mechanisms driven by switched reluctance motors (SRMs) can realize flexible control with high precision. Efficiency is an important indicator to measure the speed control system of SRMs. There are many characteristic factors affecting efficiency and strong nonlinear relationships between different characteristic parameters, which makes it difficult for analytical models and traditional neural network models to express their spatial correlation. For this reason, a convolutional neural network (CNN)-bidirectional long short-term memory network (BiLSTM) efficiency regression prediction model (CNN-BiLSTM-SENet) that integrates the attention mechanism (SENet) is proposed. Firstly, customize a formula for sensitivity analysis to screen characteristic parameters of efficiency. Secondly, build the CNN-BiLSTM-SENet model and use sparrow search algorithm (SSA) for hyperparameter optimization, input data to CNN to extract high-dimensional feature vectors that reflect complex changing relationships between features and efficiency while establishing feature channels. Embed the SENet to adaptively perceive and assign different weights to the feature channels, enhancing the influence of key features. Input the feature vectors outputted by the front-end network to BiLSTM to bidirectionally learn coupling relationships between sequences and complete regression prediction. Finally, propose improved northern goshawk optimization (MNGO) to solve the regression model to obtain the maximum efficiency and corresponding characteristic parameters. The results proved that the SSA-optimized CNN-BiLSTM-SENet model has higher fitting exactness and better prediction effect for efficiency regression prediction, and the MNGO also has stronger search ability and faster convergence.

In view of the case that the fleet of ships threatens the safety of the sea area, the scenarios of red side penetration attack, blue side air defense and antimissile, as well as three kinds of anti aircraft carrier combat strategies of land, sea and air are designed. Based on the Mozi system, the multi scheme combat simulation is carried out, and the battle damage data of both sides are obtained. On this basis, an index system based on the performance parameters of decoy and attack is established, and the operational effectiveness of the three strategies is analyzed with the analytic hierarchy process (AHP). Furthermore, a Deep Reinforcement Learning (DRL) algorithm based on AHP weight is proposed, which optimizes the sea based strategy and improves the combat effectiveness by 5.36%. The research results show that the method of scenario design, combat strategy simulation, and AHP-DQN for operational efficiency optimization based on such combat simulation software as Mozi system can provide reference for anti-ship warfare.

This paper provides a comprehensive review of the integration of advanced power management systems and learning techniques in the field of robotics. It identifies the critical roles these areas play in reshaping the capabilities of robotic systems across diverse applications. To begin, it highlights the significance of efficient power usage in modern robotics. The paper explains how advanced power converters effectively control voltage, manage current and shape waveforms, thereby optimizing energy utilization. These converters ensure that robotic components receive the precise voltage levels they require, leading to improved motor performance and enabling precise control over motor behavior. Consequently, this results in extended operational times and increased design flexibility. Furthermore, the review explores the integration of learning approaches, emphasizing their substantial impact on robotic perception, decision-making and autonomy. It discusses the application of techniques such as reinforcement learning, supervised learning and unsupervised learning, showcasing their applications in areas like object recognition, semantic segmentation, sensor fusion and anomaly detection. By utilizing these learning methods, robots become more intelligent, adaptable and capable of autonomous operation across various domains. By examining the interaction between advanced power management and learning integration, this review anticipates a future where robots operate with increased efficiency, adapt to various tasks and drive technological innovation across a wide range of industries. [ABSTRACT FROM AUTHOR]

Copyright of Automatisierungstechnik is the property of De Gruyter and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electric Power Engineering Technology is the property of Editorial Department of Electric Power Engineering Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• Customize a formula for sensitivity analysis to screen characteristic parameters. • Use an improved hybrid neural network with high fitting exactness and great prediction effect to establish efficiency regression prediction of SRM. • Propose improved northern goshawk optimization with strong search ability and fast convergence to optimize the objective function of the model, achieving an increase of 2.975% in efficiency. Six-degrees of freedom (6-DOF) parallel mechanisms driven by switched reluctance motors (SRMs) can realize flexible control with high precision. Efficiency is an important indicator to measure the speed control system of SRMs. There are many characteristic factors affecting efficiency and strong nonlinear relationships between different characteristic parameters, which makes it difficult for analytical models and traditional neural network models to express their spatial correlation. For this reason, a convolutional neural network (CNN)-bidirectional long short-term memory network (BiLSTM) efficiency regression prediction model (CNN-BiLSTM-SENet) that integrates the attention mechanism (SENet) is proposed. Firstly, customize a formula for sensitivity analysis to screen characteristic parameters of efficiency. Secondly, build the CNN-BiLSTM-SENet model and use sparrow search algorithm (SSA) for hyperparameter optimization, input data to CNN to extract high-dimensional feature vectors that reflect complex changing relationships between features and efficiency while establishing feature channels. Embed the SENet to adaptively perceive and assign different weights to the feature channels, enhancing the influence of key features. Input the feature vectors outputted by the front-end network to BiLSTM to bidirectionally learn coupling relationships between sequences and complete regression prediction. Finally, propose improved northern goshawk optimization (MNGO) to solve the regression model to obtain the maximum efficiency and corresponding characteristic parameters. The results proved that the SSA-optimized CNN-BiLSTM-SENet model has higher fitting exactness and better prediction effect for efficiency regression prediction, and the MNGO also has stronger search ability and faster convergence. [ABSTRACT FROM AUTHOR]

Hydropower development is an important strategic measure for the reform of our country's energy supply side structure, but its development often brings a large number of population migrations. Whether the resettlement funds can be used to properly resettle the reservoir resettlement is related to the sustainable development of the region and the harmony and stability of the society. The use of resettlement funds at this stage is mainly based on compensation standards and experience, without considering the efficiency of fund use. This paper introduces the principles of market economy, and considers the use of immigration funds as an investment from the perspective of immigration fund planners. According to our country's current land acquisition compensation resettlement policy, the use of funds is divided into land acquisition compensation, resettlement and follow-up livelihood assistance, and a judgment matrix is constructed according to the benefits of the resettlers to quantify the benefits and risks of different investment directions. On the premise that the three types of investment can meet the minimum needs of immigrants, the Sharpe ratio is used as a measure to calculate the fund use plan with the greatest benefit when the risk level is certain, which provides a new research paradigm for improving the efficiency of the use of immigration funds. Case analysis shows that the investment direction of the resettlement funds of the GB water conservancy project is generally in line with the resettlement wishes, but the follow-up livelihood assistance is low, and the direction of the use of funds should be adjusted to ensure the resettlement's livelihood recovery and follow-up development. [ABSTRACT FROM AUTHOR]

Wireless power transfer (WPT) for portable electronic applications has been gaining a lot of interest over the past few decades. This study provides a comprehensive review of the recent advancements in WPT technology, along with the challenges faced in its practical implementation. The modeling and design of WPT systems, including the effect of cross-coupling in multiple receivers, have been discussed and the techniques for efficiency improvement have been highlighted. The challenges of coil design, EMI shielding, and foreign object detection have been pointed out and various cutting-edge solutions have been presented. With improvements in wide bandgap technology, there is a push to operate WPT systems at mega-hertz frequencies. The reason for this is twofold: the miniaturization of the system and the ability to achieve a better magnetic link efficiency. However, with higher frequency comes the challenge of operating the power electronic components efficiently by using soft-switching techniques. Hence, an in-depth discussion on soft-switched topologies such as the Class D and Class E converters and their variations has been provided. Finally, the effects of magnetic field exposure on humans along with safety standards have been discussed.

Abstract Axial flux permanent magnet synchronous motors (AFPMSMs) have been widely used in wind-power generation, electric vehicles, aircraft, and other renewable-energy applications owing to their high power density, operating efficiency, and integrability. To facilitate comprehensive research on AFPMSM, this article reviews the developments in the research on the design and control optimization of AFPMSMs. First, the basic topologies of AFPMSMs are introduced and classified. Second, the key points of the design optimization of core and coreless AFPMSMs are summarized from the aspects of parameter design, structure design, and material optimization. Third, because efficiency improvement is an issue that needs to be addressed when AFPMSMs are applied to electric or other vehicles, the development status of efficiency-optimization control strategies is reviewed. Moreover, control strategies proposed to suppress torque ripple caused by the small inductance of disc coreless permanent magnet synchronous motors (DCPMSMs) are summarized. An overview of the rotor-synchronization control strategies for disc contra-rotating permanent magnet synchronous motors (CRPMSMs) is presented. Finally, the current difficulties and development trends revealed in this review are discussed.

The increasing popularity of electric drives employing an isolated dual-inverter (DI) topology is motivated by their superior DC-link voltage and power utilization, fault-tolerant operation, and potential for multilevel operation. These attributes are significant in battery-powered transportation, such as electric vehicles and aviation. Given the considerable freedom in modulation and control of the DI topology, this paper researches the impact of reference voltage vector distribution between the two individual inverters. The study also evaluates the influence of two well-established asynchronous modulation strategies—Space Vector PWM (SVPWM) and Depenbrock’s Discontinuous Modulation (DPWM1). Since simulation tools nowadays play a crucial role in power electronics design and concept verification, the results are based on extensive and detailed models in Matlab/Simulink. Employing the basic field-oriented control of a 12 kW induction motor with precisely parameterized SiC switching devices for accurate loss calculation, this research reveals the possibility of significant energy savings at multiple operating points. Notably, optimal efficiency is achieved when one inverter operates up to half of the nominal speed while the other solely establishes a neutral point for the winding. Moreover, the results highlight DPWM1 as a superior strategy for the DI topology, showcasing reduced converter losses. Overall, it is shown that the system’s losses can be significantly reduced just by the design of the voltage vector distribution in the drive’s operating range and the modulation strategy selection.

This study examines the improvement of electric vehicle (EV) economy by using Model Predictive Control (MPC) in power electronics, with the goal of optimizing system performance. Experimental assessments done on different battery parameters have identified a spectrum of capacities, ranging from 55 kWh to 75 kWh, and voltages, ranging from 380V to 450V, that impact the total energy storage and power production capabilities. The efficiency percentages recorded in the battery systems ranged from 90% to 95%, suggesting differences in energy losses throughout the operations of charging and discharging. Furthermore, examinations of power electronics control configurations highlighted the significance of PWM frequencies (varying from 8 kHz to 12 kHz) and modulation indices (0.75 to 0.85) on the efficiency of power conversion. The results indicated efficiency rates ranging from 94% to 97%, emphasizing the efficacy of MPC-based techniques in improving power flow. The assessment of electric vehicle (EV) performance parameters demonstrated driving ranges ranging from 140 km to 180 km, with energy consumption rates ranging from 50 kWh to 60 kWh. The efficiency metrics ranged from 2.5 km/kWh to 3.0 km/kWh, and were directly affected by the battery properties and improvements in power electronics. Moreover, there was a little change in the link between temperature variations (ambient temperature ranging from 23°C to 29°C and battery temperature from 32°C to 40°C) and efficiency. This highlights the system's sensitivity to external variables. In summary, this relationship between battery characteristics, power electronics control, and environmental conditions in determining the efficiency of electric vehicles (EVs). The results emphasize the importance of customized setups and control techniques based on model predictive control (MPC) in optimizing energy use and increasing the distance electric cars can travel. These findings provide valuable knowledge for the development of sustainable transportation solutions in the electric vehicle industry.

Summary: High‐order compensation for the inductive coupling power transfer (ICPT) system is preferred due to its high design freedom and excellent coil current harmonics suppression capability. Especially, the good harmonics suppression capability is helpful to implement the synchronous wireless transfer of energy and data with a pair of data communication coils integrated into the energy transfer coils. Thus, on basis of THD1 and THD2 comparison for different high‐order compensation topologies, the LCC‐LC compensated ICPT system with load‐independent zero phase angle (ZPA) and constant voltage output is discussed in this paper. Compared with other high‐order compensation topologies with constant voltage output such as LC‐LC, LC‐LCC, and LCC‐LCC, the LCC‐LC has the advantages of ZPA operation with zero voltage switching and less secondary‐side components. For a given magnetic coupler, infinite feasible combinations of compensation parameters can make the system accomplish ZPA and the same output characteristics. Thus, efficiency optimization of the LCC‐LC compensated ICPT system can be investigated by configuring the optimal compensation parameters. To validate the theoretical analysis, especially the efficiency improvement, the experimental platform with 270 V input and 270 V/3 kW output is designed and built. The comparative experimental results for three different the compensation parameters show the optimized system can improve greatly conversion efficiency over the entire load range, especially under light load. [ABSTRACT FROM AUTHOR]

In view of the case that the fleet of ships threatens the safety of the sea area, the scenarios of red side penetration attack, blue side air defense and antimissile, as well as three kinds of anti aircraft carrier combat strategies of land, sea and air are designed. Based on the Mozi system, the multi scheme combat simulation is carried out, and the battle damage data of both sides are obtained. On this basis, an index system based on the performance parameters of decoy and attack is established, and the operational effectiveness of the three strategies is analyzed with the analytic hierarchy process (AHP). Furthermore, a Deep Reinforcement Learning (DRL) algorithm based on AHP weight is proposed, which optimizes the sea based strategy and improves the combat effectiveness by 5.36%. The research results show that the method of scenario design, combat strategy simulation, and AHP-DQN for operational efficiency optimization based on such combat simulation software as Mozi system can provide reference for anti-ship warfare. [ABSTRACT FROM AUTHOR]

Wireless power transfer (WPT) for portable electronic applications has been gaining a lot of interest over the past few decades. This study provides a comprehensive review of the recent advancements in WPT technology, along with the challenges faced in its practical implementation. The modeling and design of WPT systems, including the effect of cross-coupling in multiple receivers, have been discussed and the techniques for efficiency improvement have been highlighted. The challenges of coil design, EMI shielding, and foreign object detection have been pointed out and various cutting-edge solutions have been presented. With improvements in wide bandgap technology, there is a push to operate WPT systems at mega-hertz frequencies. The reason for this is twofold: the miniaturization of the system and the ability to achieve a better magnetic link efficiency. However, with higher frequency comes the challenge of operating the power electronic components efficiently by using soft-switching techniques. Hence, an in-depth discussion on soft-switched topologies such as the Class D and Class E converters and their variations has been provided. Finally, the effects of magnetic field exposure on humans along with safety standards have been discussed. [ABSTRACT FROM AUTHOR]

Hybrid grids with low voltage direct current (LVdc) distribution are an attractive opportunity for the integration of electric vehicle charging stations and photovoltaic power plants. With dc connectivity reduced power losses are possible, however, multiple conversion stages can impair an efficient operation. A solution can be the use of an “interconnected” architecture that allows the integration of multiple insulated dc and ac grids. The reconfiguration of this modular topology allows optimization for different design objectives. This work investigates the system efficiency-optimized reconfiguration. Two approaches for deriving the reconfiguration of the hybrid grid connecting converter architecture based on mission profiles are proposed. A validation of the analysis via laboratory results is given.

In this paper, the proposal for the performance optimization of the wireless power transfer (WPT) system is given. The solution is based on the alternative configuration of the secondary-side rectifier. It is represented by a diode rectifier with a current doubler. Compared to the bridge rectifier, two diodes are replaced by the inductors. Initially, a system analysis was performed to investigate the electrical behavior and find the most optimal conditions referred to as terms of efficiency performance at nominal power. Due to this requirement, the rectifier inductors must be designed accordingly to meet this condition. The experimental verification was realized as well, while the proposed solution was compared to other common alternatives of the secondary-side rectification. The load sensitivity analysis in terms of efficiency performance was realized as well to observe the system behavior for a wide operation range. From the results, it is seen that the proposed alternative of the secondary-side rectification of the WPT system gives promising results in terms of high operating efficiency.

This paper provides a comprehensive review of the integration of advanced power management systems and learning techniques in the field of robotics. It identifies the critical roles these areas play in reshaping the capabilities of robotic systems across diverse applications. To begin, it highlights the significance of efficient power usage in modern robotics. The paper explains how advanced power converters effectively control voltage, manage current and shape waveforms, thereby optimizing energy utilization. These converters ensure that robotic components receive the precise voltage levels they require, leading to improved motor performance and enabling precise control over motor behavior. Consequently, this results in extended operational times and increased design flexibility. Furthermore, the review explores the integration of learning approaches, emphasizing their substantial impact on robotic perception, decision-making and autonomy. It discusses the application of techniques such as reinforcement learning, supervised learning and unsupervised learning, showcasing their applications in areas like object recognition, semantic segmentation, sensor fusion and anomaly detection. By utilizing these learning methods, robots become more intelligent, adaptable and capable of autonomous operation across various domains. By examining the interaction between advanced power management and learning integration, this review anticipates a future where robots operate with increased efficiency, adapt to various tasks and drive technological innovation across a wide range of industries.

Axial flux permanent magnet synchronous motors (AFPMSMs) have been widely used in wind-power generation, electric vehicles, aircraft, and other renewable-energy applications owing to their high power density, operating efficiency, and integrability. To facilitate comprehensive research on AFPMSM, this article reviews the developments in the research on the design and control optimization of AFPMSMs. First, the basic topologies of AFPMSMs are introduced and classified. Second, the key points of the design optimization of core and coreless AFPMSMs are summarized from the aspects of parameter design, structure design, and material optimization. Third, because efficiency improvement is an issue that needs to be addressed when AFPMSMs are applied to electric or other vehicles, the development status of efficiency-optimization control strategies is reviewed. Moreover, control strategies proposed to suppress torque ripple caused by the small inductance of disc coreless permanent magnet synchronous motors (DCPMSMs) are summarized. An overview of the rotor-synchronization control strategies for disc contra-rotating permanent magnet synchronous motors (CRPMSMs) is presented. Finally, the current difficulties and development trends revealed in this review are discussed. [ABSTRACT FROM AUTHOR]

In this paper, an optimal design of a high-efficiency DC-DC boost converter is proposed for RF energy harvesting Internet of Things (IoT) sensors. Since the output DC voltage of the RF-DC rectifier for RF energy harvesting varies considerably depending on the RF input power, the DC-DC boost converter following the RF-DC rectifier is required to achieve high power conversion efficiency (PCE) in a wide input voltage range. Therefore, based on the loss analysis and modeling of an inductor-based DC-DC boost converter, an optimal design method of design parameters, including inductance and peak inductor current, is proposed to obtain the maximum PCE by minimizing the total loss according to different input voltages in a wide input voltage range. A high-efficiency DC-DC boost converter for RF energy harvesting applications is designed using a 65 nm CMOS process. The modeled total losses agree well with the circuit simulation results and the proposed loss modeling results accurately predict the optimal design parameters to obtain the maximum PCE. Based on the proposed loss modeling, the optimally designed DC-DC boost converter achieves a power conversion efficiency of 96.5% at a low input voltage of 0.1 V and a peak efficiency of 98.4% at an input voltage of 0.4 V. [ABSTRACT FROM AUTHOR]

In this article, a shielding scheme based on ferrite magnetic antennas (SS-FMA) is proposed. The scheme can effectively provide a path for the magnetic field lines of three-dimensional couplers to be concentrated and conducted. The SS-FMA is considered to be applied for long range inductive power transfer (IPT) systems of post insulators to powering smart grid sensors and improve the efficiency under the influence of metal components. The negative influence of the aluminum flanges on the magnetic field distribution is analyzed. The suppression effects of the shielding scheme on the abovementioned influence have been analyzed. Parameters of the SS-FMA are optimized. The equivalent circuit model is established, and the abovementioned process is explained from the perspective of the circuit model. A prototype of a post insulator that includes IPT system and SS-FMA has been built. When the coils of the IPT system are attached to the flanges, the efficiency can still reach 47.8% under the influence of SS-FMA, which is an increase of 13.7% compared with no shielding scheme. When the coils are slightly away from the flanges, efficiency of the system including SS-FMA can be quickly improved to 54.3%. [ABSTRACT FROM AUTHOR]

This article proposes a real-time dynamic maximum efficiency tracking algorithm for wireless power transfer (WPT) systems with multiple receivers. The algorithm sequentially varies the net reactance of each of the receivers using switched capacitor circuits (SCCs) to reach the maximum efficiency point (MEP). The MEP in multiple-receiver systems varies in the presence of cross-coupling. This article provides an in-depth analysis of the effects of cross-coupling and proves that cross-coupling could be beneficial or detrimental to efficiency, depending on circuit conditions such as the load resistances and coupling factors among the coils. Hence, unlike previous research, this article emphasizes the improvement of the link efficiency in the presence of cross-coupling rather than the complete elimination of its effects. Experimental results have been included for a single-transmitter and two-receiver system to validate the feasibility of the proposed algorithm. [ABSTRACT FROM AUTHOR]

Power electronic transformer (PET) is the key equipment to realize the power conversion and routing of AC/DC hybrid distribution network, which can greatly enhance the flexibility and controllability of power grid. At present, PET with cascaded H-bridge (CHB) and series resonant dual active bridge (SRDAB) is widely used because of its modular structure and high efficiency. In this paper, a 1.5 MW 10 kV AC-750 V DC PET uesd in practical engineering is analyzed. Firstly, the different switching transient characteristics under the forward and reverse power flow direction are described, and the reasons for the difference are analyzed. Secondly, the current on the rectifier side of SRDAB only flows through the diode. Therefore, the switching loss of SRDAB can be reduced by locking the power semiconductor device on the rectifier side, so as to improve the efficiency of PET. Finally, the experimental test on the PET project site proves the correctness of the loss analysis and the effectiveness of the efficiency optimization method. Using the proposed method, the PET operation efficiency can be improved by about 0.2%.

This paper presents a constant-frequency multi-variable coordinated control strategy based on a series-series compensated dual-active-bridge wireless-power-transfer converter to eliminate real-time wireless feedback communication (RTWFC) and optimize efficiency. The use of switch-controlled capacitors as the primary and secondary resonant capacitors allows the continuous change of the compensation capacitance for the inverter soft-switching and reactance matching, respectively. The output voltage is regulated by tuning the phase-shift angle in the active rectifier bridge. The optimal load resistance for efficiency improvement is matched by adjusting the phase difference between the rectifier voltage and current based on the load and mutual inductance estimation. Moreover, the phase shift of the inverter, which is load-independent, and the coupling coefficient between the coils are positively correlated. Nevertheless, the drawbacks of the proposed control strategy are that optimal load matching is only valid for heavy load and constant current cannot be realized while keeping the constraint of the decoupled control. The proposed control strategy is experimentally validated on a prototype. The efficiency improvement is 5% compared to the conventional voltage tuning with a diode rectifier at the rated output power and in the normal position, and the peak efficiency reaches 93.6% at a 24 V output under the coupling coefficient of 0.3. In addition, a faster transient response was demonstrated in the proposed control strategy without RTWFC for output regulation.

Based on the unipolar-duty-cycle (UDC) modulation technique, this article presents a hybrid control strategy for a series–series compensated inductive power transfer (IPT) system. By adjusting the duty cycle and the operating frequency, zero-voltage switching (ZVS) and constant-current output (CCO) can be achieved with varying coupling coefficients and load. Furthermore, as the proposed strategy enables the IPT system to lower the frequency of operation, it provides higher efficiency in the overall output power range than the conventional variable-frequency control methods. The basic principle of the UDC control strategy and its characteristics are introduced, and the system performance under UDC is analyzed and compared with the performance achieved by conventional control methods. Based on this, the UDC closed-loop control scheme, which combines PI control and hysteresis control, is proposed for the dynamic tracking of the ZVS and the CCO under a wide range of coupling coefficients and load. To validate the practicability of the proposed control strategy, a 500-W experimental prototype is configured. The simulation and experimental results indicate that the proposed scheme can stably and accurately track the ZVS and the CCO under varying parameter conditions, and it significantly improves the system efficiency. Especially, the system efficiency is improved by approximately 1.75% under light-load conditions as compared with that of the conventional control method. In addition, since the proposed method employs only one control loop, the cost and complexity of the IPT system are reduced. [ABSTRACT FROM AUTHOR]

This paper presents a comparative study between the traditional phase shift (also referred to as the Single-Phase Shift (SPS)) and the Dual-Phase Shift (DPS) controlled Triple Active Bridge (TAB) converter. Being a multi-port DC-DC converter with flexible power flow control and characterized by high power density, the TAB converter is applicable in almost any situation where a DC-DC converter is needed. With the availability of multiple control schemes, this work highlights the advantages and disadvantages of the most employed control scheme used on the TAB converter, in comparison with the DPS control scheme that has so far been applied only on Dual-Active Bridge (DAB) converters. As an example, for a TAB converter with a 14 kW maximum power capacity, the work sees the comparison of the backflow power, the maximum possible current, the processed power at the different ports of the converter, the transformer voltage and current waveforms, and the Total Harmonic Distortion (THD). Based on the results obtained, we found that the DPS-controlled TAB converter was more efficient when applied to the TAB converter compared to the traditional phase shift control algorithm. [ABSTRACT FROM AUTHOR]

This paper proposes a novel Redundant Cooperative Control (RCC) strategy to address the pollination sequence planning problem for a mobile pollination robot in the greenhouse. Firstly, the RCC strategy divides the robot's workspace into subspaces based on the distribution of flowers through clustering. Subsequently, the RCC strategy plans the traveling salesman problem within the visual field of these subspaces, seeking a compromise solution for an optimal path. Finally, the RCC strategy utilizes the redundant motion capabilities of the mobile chassis and robotic arm to accomplish the pollination task during the movement. The RCC strategy exploits the available redundancy in both the agricultural robot's mobile platform and end-effector, carefully balancing computational complexity and path quality. To validate the effectiveness of the RCC strategy, we designed a series of experiments conducted on our pollination robot platform, measuring different strategies. The results demonstrate that the RCC strategy achieves an average pollination rate of 7.5 s per flower, representing a 36.4% improvement compared to the most common intermittence strategy. Furthermore, the RCC strategy can be extended to tasks such as harvesting and pruning, significantly enhancing the efficiency of robot task execution even in industrial and service sectors. • Proposed a redundant cooperative control strategy (RCC). • Designed a tomato pollination robot with redundant motion capability. • The RCC strategy can be applied to pollination in motion. • The pollination robot can achieve a pollination rate of 7.5 s per flower. [ABSTRACT FROM AUTHOR]

• An improved cascade method for compression-absorption heat pump is proposed. • The improved cascade heat pump can output temperature 110 °C at inlet source 10 °C. • The energy performance of improved cascade method is 16.2% higher than existing mode. • The exergy performance of novel cascade method is raised by 19.2% than existing mode. • The novel cascade method can increase the available heat capacity by 238.4%. Air is a readily available and renewable source, but its efficient utilization for industrial heating is hindered by the significant temperature mismatch between the low-grade air source and the high-temperature industrial demand. Heat pumps can elevate the source temperature from low to high levels. However, there is still a significant knowledge gap in achieving output temperature exceeding 90 °C when the input source is below 30 °C. While there are some preliminary studies on air-source heat pumps operating in the mentioned temperature range, they have yet to distinguish the respective coupling temperatures required for different cascaded components. Therefore, the optimal cascade configuration between various sub-cycles has not been established, and the full efficiency potential remains untapped. To address the identified limitations, in this work, an advanced cascade method is proposed and applied to the compression-absorption heat pump (CAHP). The novel cascade method allows independent control of the coupling temperature in different branches as needed, facilitating an optimal cascade configuration between various subloops. Consequently, the operating efficiency of CAHP is optimized. Simulation results show that the proposed cascade method reduces the exergy destruction of CAHP by 6.3% compared to the existing mode. Moreover, it always achieves higher efficiencies in the studied conditions, with a maximum increase in the coefficient of performance and exergy coefficient of performance by 16.2% and 19.2%, respectively. Under ambient temperature of 10 °C to –30 °C and an output temperature of 100 °C, the improved cascade CAHP exhibits an increase in heating capacity, ranging from 57.2% to 238.4% higher than the existing mode. These advantageous features contribute to achieving cleaner industrial heating with air source heat pumps. [ABSTRACT FROM AUTHOR]

Featured Application: 3-phase industrial PFC converter. In this paper, the main aim of the study was the investigation of the possibilities of power inductor design, reflecting the performance of the component itself, as well as the operational efficiency of the power factor correction (PFC) converter. PFC inductors represent a key component of the converter, while within the design of any magnetic component, several design rules must be considered to provide proper operational performance. Here we discuss skin-effect, while the proximity effect and formation of fringing flux pose a more serious problem in terms of mitigating their negative impact. Therefore, in this study, the space is devoted exclusively to the analysis of the impact of the fringing flux of the PFC inductor and subsequently to the possibilities of its suppression. The resulting optimizations are reflected in the investigation of the operational efficiency of the PFC converter. [ABSTRACT FROM AUTHOR]

The topology and parameter characteristics of the wireless energy transmission system are the main factors affecting the system's performance. A series–parallel–series–parallel (spsp) topology for magnetically coupled wireless energy transmission is proposed to address the problems of low efficiency and low output power when transmitting electrical energy in the conventional magnetically coupled topology. The spsp topology is compared with the conventional topology based on circuit theory, and the two structures are modeled, characterized, and verified in detail. Simulations and tests are performed for the transmission conditions, an improved Gray Wolf optimization algorithm is proposed, and a physical system is built. Experiments show that the spsp structure is superior near the designed circuit parameters when the network works in a resonant state. The improved Gray Wolf optimization algorithm is then used to find the optimal parameters, and the transmission efficiency reaches 90.53%, which effectively improves the transmission performance of the system. The established physical system utilizes the optimized parameters for coil structure and coil offset experiments, and the average transmission efficiency is 83.75%, with an error of 6.78% calculated by data measurement. The rationality of the proposed structure and the correctness of the simulation parameter design method are verified, and it is hoped that the proposed system and circuit structure in this paper will provide a reference for the design of a magnetically coupled wireless energy transmission system. [ABSTRACT FROM AUTHOR]

This paper uses the three-stage DEA method to measure the input–output efficiency of China's 23 listed power generation companies (mainly thermal power generation) in 2019, and uses the SFA regression model to eliminate environmental elements and random disturbances. The results show that in a non-homogeneous environment, the scale efficiencies of most power generation companies are greater than or equal to their pure technical efficiencies. These companies should first improve management and technical levels, and then optimize the scale of investment. Furthermore, after removing environmental variables, half of the companies should turn to increasing economies of scale instead of diminishing economies of scale. It can be seen that environmental factors, such as the degree of regional development and IPO time, have reduced the economies of scale of enterprises, so they should strengthen the communication between different regions, and the government should provide assistance to companies that are listed late. [ABSTRACT FROM AUTHOR]