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This study develops a new method to evaluate the economic viability of co-generation electric vehicle stations that concurrently generate electricity and hydrogen for charging battery electric vehicles and refueling hydrogen vehicles. The approach uniquely differentiates the costs associated with various energy outputs in co-generation stations and includes often-overlooked peripheral devices critical for accurate evaluation of the levelized cost of electricity (LCOE) and hydrogen (LCOH). The method was tested across three design configurations: two featuring single storage options (battery and fuel cell, respectively) and a third using hybrid storage employing both. Each configuration was modeled, simulated, and optimized using HOMER Pro 3.14.2 to determine the most optimal sizing solution. Then, based on the optimal sizing of each design, LCOE and LCOH were evaluated using the proposed method in this study. The analysis revealed that excluding often-overlooked peripheral devices could lead to a 27.7% error in LCOH evaluation, while the impact on LCOE was less than 1%. Among different configurations, the design with hybrid storage proved economically superior, achieving a total levelized cost of energy (TLCOE) for the entire system of USD 0.113/kWh, with the LCOE at USD 0.025/kWh and LCOH at USD 0.088/kWh (or USD 3.46/kg). Comparative analysis with state-of-the-art studies confirmed the accuracy of the proposed method. This study provides a more precise and holistic approach that can be leveraged for the feasibility analysis of electric vehicle stations globally, enhancing strategic decision-making in sustainable energy planning. [ABSTRACT FROM AUTHOR]

Five‐phase permanent magnet synchronous machine (PMSM) can operate under open‐circuit faults with the appropriate current regulations. However, the traditional current regulations based on the five‐phase half‐bridge inverter have to satisfy the constraint of zero neutral point current, which limits the fault‐tolerant performance of the machine. Thus, this paper investigates the current regulation based on the five‐phase six‐leg (FPSL) inverter, which relieves the zero‐neutral point current limitation, and both current regulations considering the maximum torque (MT) and minimum copper loss (MC) are derived under different open‐circuit conditions. The cost of the system has increased, but with the new regulations, better fault‐tolerant operation capability of the machine can be obtained under all kinds of open‐circuit faults. Moreover, with the introduction of the neutral point current, the machine can work under triple‐phase open‐circuit faults. In conclusion, the proposed control scheme based on the FPSL inverter expands the fault‐tolerant operation capability of the five‐phase PMSM. The experiment results prove the effectiveness of the proposed current regulation on increasing average torque or reducing copper loss under fault‐tolerant operation. [ABSTRACT FROM AUTHOR]

Wireless power and data transmission (WPDT) solutions for medical implants are highly desired. However, achieving a high-power transmission efficiency and data rate simultaneously over an inductive link remains a significant challenge. This paper presents an innovative WPDT circuit that incorporates additional MOSFETs with an inductor in a Class-E power amplifier (PA), achieving amplitude-shift keying (ASK) modulation to address this issue. Firstly, the efficiency of the inductive power transmission link and Class-E PA was analyzed, providing design insights. Then, leveraging the insights, the proposed circuit was designed in such a way that it could effectively switch between two load networks to maintain high transfer efficiency for ASK modulation. Based on the load networks, the relationship between introducing the inductor's value and the data modulation index (MI) was derived to help achieve the desired high-power transmission efficiency. Additionally, the design and calculation of the proposed circuit are also presented. Finally, the proposed circuit was validated through simulations and experiments, demonstrating a power delivery to a load of 84.1 mW with a power transmission efficiency of 70.8% at a data rate and carrier frequency of 3 Mbps and 16 MHz, respectively. Furthermore, the bit error rate (BER) is less than 10−6 with an MI of 10%. [ABSTRACT FROM AUTHOR]

The past decade has witnessed a surging interest in the study of magnetic tactile sensors that can detect subtle changes in both normal and shear forces. However, due to the lack of guidance by appropriate theoretical models, the development of previous magnetic tactile sensors relies either on a trial‐and‐error manner or tedious point‐by‐point experimental calibrations, which are costly and time‐inefficient. Here, a theoretical model integrating magnetics, artificial neural networks, and nonlinear solid mechanics is proposed for the first time to guide the design of 3D magnetic tactile sensors. Then, a button‐shaped magnetic tactile sensor prototype that can detect subtle triaxial force changes is fabricated, which relates the nonlinear magnetic flux density to the external force, without burdensome calibration procedures. The sensor can achieve an axial measurement error of less than 1% and an in‐plane error of less than 3.7% with excellent durability. This study provides a comprehensive understanding of magnetic tactile sensors and sheds light on their applications in soft robotics, intelligent manipulation, and human–robot interaction (HRI). [ABSTRACT FROM AUTHOR]

The new topology of the dual-armature flux-switching permanent magnet machine (DA-FSPM) leads to new characteristics and issues in the control of the machine, of which the mutual inductance of the two sets of armature windings is the most important one. This paper proposes a novel position–sensorless control method based on high-frequency injection (HFI) for DA-FSPM. The high-frequency model of the machine is derived, and the theory of the position estimation method is proposed. Different from the conventional HFI-based position estimation method, the proposed method utilizes the mutual inductance of the DA-FSPM rather than the machine saliency. Meanwhile, because the extracted position information based on the mutual inductance is more obvious, the proposed method also has better steady and dynamic performance. Then, the position observer based on the phase lock loop and the initial position detection method for the DA-FSPM is proposed. The experiments are executed on a DA-FSPM prototype with three-phase stator windings and five-phase rotor windings to prove the effectiveness and superiority of the proposed method. [ABSTRACT FROM AUTHOR]

To improve the torque performance limited by the low carrier ratio operation in motor drive system, a master–slave motor drive system based on dual stator winding structure is researched in this article. A high-frequency harmonic current is injected through the auxiliary windings to compensate the torque ripple and dynamic issue caused by the low carrier ratio. The basic operation principle in master–slave motor drive system is presented and then the turn ratio, mutual inductance, and carrier ratio in both windings are studied to achieve the optimization for the torque performance and power loss. The control method aiming at depression on toque ripple and load disturbance is proposed and gets merged with the vector control strategy. The loss analysis considering the injected high-frequency current is presented to compare with the three-phase system in high carrier ratio operation. It is found that a 30% total loss reduction can be achieved under the same torque ripple. Both simulation and experiments show the effectiveness of proposed master–slave windings system and the control strategy. [ABSTRACT FROM AUTHOR]

Leakage inductance is one of the key parameters of a transformer, and it is often intentionally integrated into transformers. Rogowski's equation is generally used for leakage inductance calculation; however, it is only applicable to concentric winding transformers where windings have the same height. Consequently, it has limited applications. This paper proposes a transformer leakage inductance calculation method using a double Fourier series. The limitation of Rogowski's leakage inductance equation was analyzed in practical applications, and a new model for calculating the leakage inductance of a double-group-overlapping winding transformer was derived. Experimental prototypes of transformers were developed, and their simulation models were built in Ansys. The correctness of the proposed calculation method for transformer leakage inductance using a double Fourier series was verified by comparing the calculation results with the simulation and measured ones. A sensitivity analysis was also conducted by studying the variations in different parameters that might affect the leakage inductance value. The proposed calculation model gives an intuitive and simple method with less calculation and design effort while maintaining reasonable accuracy for leakage inductance calculation. In addition, the featured double Fourier series approach has a wider range of applications than Rogowski's equation. [ABSTRACT FROM AUTHOR]

The reconfigurable modular vehicle group can transform into different configurations according to different requirements to be competent for various tasks and scenarios and to facilitate the utilization of robots in unstructured scenarios. Efficient and effective reconfiguration strategies and path planning are essential for improving the performance of modular vehicle groups. First, a multi-sensing four-wheel-drive Mecanum vehicle was built, which was equipped with UWB positioning (based on wireless carrier communication technology), communication based on ESP8266 modules, ultrasonic ranging and a magnetic structure. Second, concerning the indoor storage environment, a UWB two-way bilateral ranging and positioning system was designed, and the experimental accuracy for positioning could reach ±0.1 m. Third, a path planning strategy based on the improved artificial potential field method was adopted. According to the target configuration as well as the obstacle avoidance requirements, the motion space was converted into a gravitational field and a repulsive force field, and the vector superposition of the gradients was used for the path planning of each vehicle in turn. Depending on the reconfiguration command and the connection matrix, the magnetic structure would strengthen or disconnect the vehicle group configuration. Finally, the vehicle reconfiguration from the stochastic dispersion state to the target configuration and the transition between different configurations were accomplished using the proposed strategy in both simulations and experiments. [ABSTRACT FROM AUTHOR]

Self-reconfigurable vehicles are able to transform into new formations on the basis of mutual communication and positioning so as to adapt to a new environment and new tasks. Compared with fixed-formation vehicles, reconfigurable vehicles feature multifunction and high reliability. First, a modular vehicle with a Mecanum wheel is designed, and a motion control method of a modular vehicle is derived through the establishment and analysis of its kinematics model. Afterwards, a visual positioning system based on AprilTag is designed, and the reconfiguration experiment of modular vehicles is completed in order to validate the feasibility of the proposed control method. A hardware control platform is built, which is able to realize the omnidirectional movement of the vehicle in the plane. The proposed modular vehicles with the corresponding control method successfully completes centralized perception, trajectory planning, and self-reconfiguration, which can be potentially applied in various scenarios, such as orientation guidance and logistics handling. [ABSTRACT FROM AUTHOR]

With the development of the logistics industry, low-voltage systems, such as intelligent logistics vehicles, have also started to propose application scenarios for wireless power transfer systems. As most logistics vehicles use lithium batteries for energy supply, the wireless charging system has to adapt to the charging characteristic curve of lithium batteries. In this paper, a dual-transmitter single-receiver compound resonant compensation topology with a high voltage ratio is proposed, and a corresponding magnetic coupler is designed and optimized through finite element analysis, which guarantees adaptive output curves according to the working state. A 1 kW experimental platform is established to verify the theoretical analysis, which realizes a high voltage transformation ratio with 90.3% efficiency. Throughout the whole charging process, the output curve agrees with the charging profile of the lithium battery, which can greatly extend the service life of lithium batteries. [ABSTRACT FROM AUTHOR]

Wireless charging to autonomous underwater vehicle effectively prolongs the attended time and extends the endurance mileage. As the most promising underwater power feeding technique, inductive power transfer is also faced with challenges such as the attenuation in seawater, ocean current disturbance, etc. Special concerns in terms of power quality, efficiency improvement, and mechanical fixing need to be considered when designing the underwater electromagnetic coupling structure. An attenuation model in seawater is established in this article. The optimal working frequency range is refined for a specific transmission media. Different from the wireless power transfer system in the air, the underwater WPT system features tight coupling between the transmitter and receiver. The optimal range of coupling coefficient needs to be redesigned, as high coupling coefficient incurs frequency splitting and the increase of harmonic component, while low coupling coefficient results in low efficiency. Based on the theoretical analysis, a self-latching coupling structure is proposed with lightweight design on receiver side. System parameters are optimized correspondingly and a 3-kW experiment validates the theoretical analysis. [ABSTRACT FROM AUTHOR]

Energy storage units (such as battery or ultracapacitor) can help to reduce the power fluctuation in the impedance source network converter applications such as the photovoltaic (PV) and fuel cells systems. Due to the unknown dynamic characteristics of the energy stored impedance network, the unexpected oscillation and inrush currents in dynamic process might threaten the storage device safety. In this article, an energy stored quasi-Z-source converter with the battery is modeled and analyzed including the transient capacitor current. The impact of the network internal resonance on the battery current control loop is mathematically explored. The resulted conflict between the zero steady-state error and bandwidth requirement is revealed. That yields the sacrifice and limitation of the closed-loop dynamic performance in the conventional methods. An active damping technique is then proposed to ensure the extended bandwidth and better dynamic performances under different state of charge (SOC) occasions. The theoretical analysis and performance are both verified by the simulations and experiments. [ABSTRACT FROM AUTHOR]

This paper proposes a torque distributed control strategy for the multiphase machines in the hybrid energy storage system application. Different with the conventional energy current regulation method, the system energy management is researched by the machine torque distribution in different sets of windings. The load power is then afforded by the energy storage devices connected with the windings through the inverters. The principle of the distributed torque operation is explored with a dual three-phase permanent-magnet synchronous machine model and the asymmetrical windings operation is explained with the flux vector diagram. The windings decoupling compensation, flux observer, and parameter identification methods are presented. Based on the proposed strategy, a power frequency dividing coordinated regulation is achieved. The hybrid energy storage devices can directly respond to the average or instantaneous parts in the load torque and power fluctuation. Simulation and experiments are demonstrated with different operation cases. [ABSTRACT FROM AUTHOR]

Wireless power transfer (WPT) has attracted attention from academia and industry in recent years. WPT has natural electrical isolation between primary and secondary side, which ensures safe charging in an underwater environment. This breakthrough technology greatly facilitates the deep-sea power transmission. However, at the current stage the transferred power and energy efficiency level are not up to that of the WPT system in the air. The major concerns include the attenuation is seawater, extreme temperature and pressure conditions, disturbance of ocean currents, and bio-security. Three questions are answered in this paper: first, the expressions of eddy current loss and attenuation of electromagnetic wave in seawater are unified, and the influence of seawater as transmission medium on the WPT system is discussed. Second, the evolution of electromagnetic coupling structure suitable for underwater applications is studied. Third, the loss and heating effects of an underwater WPT system and the corresponding bio-fouling phenomenon are investigated. The questions above were addressed through analysis of electrical properties, coupler structures, and bio-fouling effects of the underwater WPT system. This paper will facilitate the study and research on underwater WPT applications. [ABSTRACT FROM AUTHOR]

Devices and the passive components in the single-phase impedance source network converter are sensitive to the double-line-frequency (DLF) pulsation. Previous research works have studied the power decoupling and the DLF equivalent model for the power pulsation suppression method. This paper explored the DLF transfer routes in the impedance source network. A comprehensive stress derivation of the passive components and switching devices are obtained for the suppression method enhancement and optimization. For the DLF passive suppression method, the explanation for the passive component volume issue is provided from the stress aspect. The component value solution space and corresponding design guidance are presented. For the DLF active suppression method (ASM), a buck-type dc-side ASM suppression method is employed and its optimization is demonstrated with the assistant circuit stress analysis. The total capacitor and inductor values get reduced by 77% and 25%, respectively. The corresponding pulsewidth modulation method implementation and the common-mode leakage current demonstration are also presented. The effectiveness of the theoretical analysis and optimization methods is verified by simulations and experiments. [ABSTRACT FROM AUTHOR]

Converters with impedance source networks combine their one-stage energy conversion with the function as buck and boost converters. Due to this fact, they are very attractive to the dc–ac applications. Many literatures have focused on the stress analysis and control enhancement of the impedance network in the dc side. For a better system design and control, the synthesis and interaction principle between the ac and dc side of the converters is required. This paper first presents small-signal modeling for the bidirectional quasi-Z-source converter by the circuit-averaging technique. Compared with previous modeling based on the shoot-through duty ratio, the modulation ratio is included for the ac-side analysis. It is revealed that the oscillation in the modulation ratio could be triggered by the ac current controller, due to the magnitude margin issue caused by the impedance network, and then instability in the impedance network can be observed, including the system input current. Based on the theoretical analysis, a design guideline for the ac current controller is provided. Experimental validation for both the model and analysis is demonstrated and the results are in good agreement with the theoretical analysis. [ABSTRACT FROM AUTHOR]

To improve the performance and integration of the power train of electric vehicles power, a dual three-phase permanent magnet synchronous machine (PMSM) drive is investigated to achieve hybrid energy storage system power management. Two sets of motor windings are connected with ultracapacitors and a battery, respectively, through the inverters. First, the operation modes of the integrated system are studied by modeling and vector diagram analysis. A new control scheme is then established to enhance the regulation for unbalanced winding power distribution. The approach to suppress the motor harmonics current under the unbalanced power operation is also discussed. Finally, a frequency dividing coordinated control is performed for good dynamic response and seamless transient process. Both simulation and experiment results verify the effectiveness of the proposed system and the control strategy. [ABSTRACT FROM PUBLISHER]

For maximizing the power transfer in an inductive power transfer system, the operating frequency of the system is normally designed to be the same as the resonant frequency of the secondary power pick-up. But the load deviation reflected from secondary side to primary side will result in the frequency mismatch issue. Therefore, the contactless load detection technique is significant to ensure the power transfer efficiency and capacity. The emerging technique taking advantages of the amplitude decay rate in a transient process is promising. The robustness and practicability can get enhanced and the complicated steady circuit model is avoided. However, the accuracy for the small resistance application is still a challenge even with sophisticated compensation algorithms. This paper classified the system detectable region through the root locus method. The transient process in different subregions is excavated mathematically. It is revealed that the variation of the system from the second order to fourth order is the key issue for the detection error in the small load resistance application. The analysis brings out a novel automatic contactless load detection method to extend the detection range. Both simulation and experimental results verified the effectiveness of the proposed theory and detection method. [ABSTRACT FROM AUTHOR]

The impedance-source network converter, utilizing a unique LC network and previously forbidden shoot-through states, provides the ability to buck and boost the input voltage in a single stage. However, the inrush shoot-through current (STC) in startup or transient process might cause undesired current stresses on converter devices. This paper focuses on the STC sensing for an effective inrush current limitation by the combined current sensing technique in the quasi-Z-source inverter. STC and phase currents for the inverter control strategy are obtained simultaneously. No extra hardware is needed and the effects of current sensor bandwidth and duty cycle on the sensing accuracy are analyzed mathematically. The voltage spike gets avoided by integrating the stray inductance into the impedance network. Finally, an STC control loop based on proposed method are embedded in the field-oriented control strategy. The inrush STC and the device current stress in the transient process get suppressed. Simulation and experimental results from a quasi-Z-source inverter validate the feasibility of the proposed methods. [ABSTRACT FROM PUBLISHER]

An ultracapacitor–battery hybrid energy storage system (HESS) for an electric vehicle (EV) based on a bidirectional quasi-Z-source inverter (qZSI) is proposed in this paper. The buck/boost characteristic in the qZSI enables the HESS incorporated into the traction inverter system. The battery converter can be eliminated and the rated voltages for the battery package and UCs are reduced. The steady power distribution principle is explained under various operation modes. An enhanced frequency dividing coordinated control strategy is established to optimize the dynamic power regulation and the battery current stress in short timescale. Both the simulation and experimental results in time and frequency domain validate the performance of the proposed HESS. [ABSTRACT FROM PUBLISHER]

This paper proposes an ultracapacitor (UC)-battery hybrid energy storage system (HESS) for electric vehicle based on asymmetric bidirectional Z-source topology. Compared with the conventional two-stage design, the HESS can be incorporated into the traction inverter system, leading to better performance and lower cost. The UC energy can be effectively utilized due to the buck/boost characteristic in the Z-source converter; meanwhile, the battery converter gets eliminated in this case. The assumption about the symmetry in the Z-source topology impendence network states for the conventional analysis no longer applies to the proposed HESS configuration. The asymmetric characteristic related with the uneven power distribution of UCs and battery is mathematically excavated in detail. The frequency dividing coordinated control is proposed to exploit the advantages of UCs and battery. The battery peak current estimation is then investigated. Finally, the steady performance and transient response in both traction and regenerative modes are verified by simulation and experimental results. [ABSTRACT FROM PUBLISHER]

In this paper, an inductor–inductor–capacitor (LLC) resonant dc–dc converter design procedure for an onboard lithium-ion battery charger of a plug-in hybrid electric vehicle (PHEV) is presented. Unlike traditional resistive load applications, the characteristic of a battery load is nonlinear and highly related to the charging profiles. Based on the features of an LLC converter and the characteristics of the charging profiles, the design considerations are studied thoroughly. The worst-case conditions for primary-side zero-voltage switching (ZVS) operation are analytically identified based on fundamental harmonic approximation when a constant maximum power (CMP) charging profile is implemented. Then, the worst-case operating point is used as the design targeted point to ensure soft-switching operation globally. To avoid the inaccuracy of fundamental harmonic approximation approach in the below-resonance region, the design constraints are derived based on a specific operation mode analysis. Finally, a step-by-step design methodology is proposed and validated through experiments on a prototype converting 400 V from the input to an output voltage range of 250–450 V at 3.3 kW with a peak efficiency of 98.2%. [ABSTRACT FROM PUBLISHER]

The series–parallel resonant converter (also called line level control (LLC) resonant converter) is one of the most suitable topologies for dc–dc power supply. This study introduces the LLC resonant converter into the on‐board battery chargers for the plug‐in hybrid electric vehicle (PHEV) applications. Different from the previous literature which has focused on the wide operation range and hold‐up time requirement in the LLC design, this study is mainly focused on battery load characteristics and its impact on the charger design. First, to guarantee high efficiency in the light‐load condition in the constant voltage charging stage, the optimum LLC switching frequency range is derived. Second, considering the constant current charging function in the battery charger, the impact of peak load current on the LLC converter is discussed. The boundary between zero‐voltage switching (ZVS) and zero‐current switching (ZCS) in the constant current charging application is analysed. The trade‐off among the minimum load voltage, maximum charge current and resonant capacitor is studied in detail. Finally, the optimal design method for the LLC resonant converter used in the PHEV battery charger is proposed. The proposed methods are validated through experiments on a 400 V/6 kW PHEV charger system with 97% efficiency. [ABSTRACT FROM AUTHOR]

This paper proposed an enhanced dc preexcitation for a variable-voltage variable-frequency-controlled induction motor drive system. Voltage vectors were adjusted according to the reactive component of the motor current, which promptly established the effective value of the motor flux linkage at the preexcitation stage and restrained its trajectory strictly as a round circle all through the starting process. The enhanced dc preexcitation control led to more negligible flux-linkage distortion, less torque vibration, and significantly smaller inrush current. Experiments on a 380-VAC/315-kW adjustable speed drive system validated the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

In this paper, the interaction between the energy storage (ES) power distribution and system efficiency enhancement is researched based on the energy stored quasi-Z-source inverter. The corresponding current counteraction, stress reduction, power loss profile, and efficiency enhancement around the embedded energy storage units are studied in details. Firstly, the current counteraction effect on the device current is presented with the embedded ES source. The corresponding reduction in the device current stress is revealed. Then, the detailed device power loss expressions with current redistribution in the impedance network are explored mathematically. A quasi-inverted-trapezoidal power loss profile is found with the embedded source power distribution. To further increase the overall system efficiency, an optimal energy efficiency tracking strategy is proposed for the ES-qZSI (energy-stored quasi-Z-source inverter) based on the power distribution control. Both the simulation and the experiment verified that the power loss is reduced by over 40% through the proposed efficiency enhancement method. The device current and loss analysis for the embedding of energy storage can also be extended to the operating range optimization in other ES systems. [ABSTRACT FROM AUTHOR]

A correction is presented for the article "Synthesis and Design of the AC Current Controller and Impedance Network for the Quasi-Z-Source Converter," by Zipeng Liang, Sideng Hu, Huan Yang, and Xiangning He.