This paper proposes a dual-frequency modulated wired/wireless four-port converter for photovoltaic (PV)-battery systems, with application examples including CubeSat electrical power systems. The proposed converter features the following advantages: 1) it achieves enhanced efficiency and compact system integration by combining PV, battery, wired and wireless load interfaces through an innovative multi-port configuration, 2) the shared utilization of power devices by both wired and wireless power circuit enhances the power density of the converter, 3) zero-voltage-switching (ZVS) operation is fully realized through the co-optimization of turns ratio and shifted phase, and 4) the proposed dual-frequency modulation scheme effectively reduces power losses while achieving ZVS operation. In addition, an adaptive power management strategy is proposed to regulate hybrid wired/wireless outputs, while achieving PV maximum power point tracking and battery charging/discharging. A 1.2 kW prototype with hybrid inputs and wired/wireless outputs is experimentally validated, the results demonstrate a full-load efficiency of 89.5%. This verifies the effectiveness of the proposed topology and control methodology.

In noncoaxial rotary wireless power transfer (WPT) applications, the changing distance and angle between coils cause mutual inductance fluctuations, which in turn lead to significant output power pulsation, making it challenging to achieve stable power delivery. To realize stable power supply for rotary WPT systems, this paper investigates a typical noncoaxial arc-surface rotary coil structure and provides a detailed analysis of the mutual inductance variation during coil rotation. Building upon this foundation, a multi-Tx single-Rx curved rectangular coil configuration is proposed to reduce the mutual inductance fluctuation between Tx and Rx coils, and the parameters design for the proposed coils is carried out based on the theoretical analysis of mutual inductance. To suppress the power pulsation at the output, a Buck converter is cascaded following the rectifier circuit at the Rx side, and a closed-loop control strategy achieving full-feedforward of the pulsating current is proposed. A proof-of-concept prototype of 80 W is built and experimentally validated. Experimental results show that the current ripple at pulsation frequency is reduced by 81.33% and minimum efficiency is increased by 27.9% compared with the case without closed-loop control, which confirms the accuracy of the theoretical analysis and demonstrates the effectiveness of the proposed power pulsation suppression methods.

In low-voltage, high-current, and high-distance-diameter (d-D)-ratio applications, the magnetically coupled resonant wireless power transfer (MCR WPT) has been confronted with some new challenges, including low coupling coefficient between transmission coils, high-voltage/current stresses on resonant components, large conduction loss of the coil branch, and power switches, which further deteriorate the system efficiency and reliability. In view of above issues, a novel three-stage scalable multimodule parallel MCR WPT architecture is proposed in this article, which includes the input stage, the coil stage, and the output stage, and the specific circuit topology of each power stage is determined subsequently. The transfer characteristics are analyzed by the model of a multimodule parallel system with two sub-modules using the fundamental harmonic approximation (FHA) method. Meanwhile, three different output-stage circuits and the corresponding control schemes are compared to optimize the system performance. Furthermore, a system parameter design guideline is presented from the aspects of high coupling coefficient, low-voltage/current stress on resonant components, and wide-range soft-switching realization. Finally, a 1 kW prototype with the d-D ratio of 1 (3030 cm) is built and the experiments on three different output-stage topologies are carried out and compared, and the optimal system efficiency is 85.2%.

The multimodule series-parallel (MMSP) architecture demonstrates significant advantages, including reduced voltage/current stress on power switches, excellent power scalability, and enhanced reliability, making it an effective solution for high-power wireless power transfer (WPT) applications. The critical challenge in MMSP WPT systems lies in achieving balanced voltage/current distribution among modules. This paper specifically investigates an input-parallel output-series configuration employing LCC-LCC WPT modules, elucidating the imbalance mechanism caused by parameter mismatches through time-domain transient analysis. The equivalent circuit model of the LCC-LCC WPT module is established using fundamental harmonic approximation. Combined with phasor diagram analysis, the imbalance conditions under three typical parameter mismatch scenarios with and without cross coupling are systematically analyzed and predicted. To achieve voltage/current balance between modules, a single-voltage-loop control scheme is adopted, and the regulator parameters are designed. Experimental validation on a dual-module LCC-LCC WPT prototype confirms the theoretical analysis and demonstrates the effectiveness of the proposed methodology.

Wireless power transfer (WPT) technology offers a promising solution for powering monitoring devices on industrial rotating shafts, overcoming the limitations of wired methods such as wear, structural complexity, and instability. In this paper, a WPT system based on magnetic resonant coupling is proposed, employing a curved-surface coil structure to enhance magnetic field coverage. The system is designed with advantages of safety, stability, and convenient installation. COMSOL simulations are conducted to optimize coil geometry and transmission distance, with an S-S compensation network adopted. Simulations and experiments are further carried out to evaluate efficiency and verify reliability. Results show that when two transmitting coils are arranged 180° apart and four receiving coils are evenly spaced at 90° with a transmission distance of 3 cm, the system achieves optimal performance, delivering an average power of 25.6 W with an efficiency of 73%. The proposed system demonstrates feasibility and provides an effective solution for stable wireless power supply in industrial rotating shaft monitoring applications.

Multi-port wireless power transfer (WPT) technology can realize non-contact power transmission between multiple devices, which is potentially used in the integrated system of PV, energy storage, and charging, cooperative power supply for multiple unmanned aerial vehicles, etc. The simultaneous transmission of power and information between multiple ports is crucial to the intelligence and automation of WPT systems. However, the research on simultaneous wireless power and information transfer (SWPIT) is really limited. In this paper, an on-off keying multi-port SWPIT methodology based on high-frequency carrier injection is proposed for magnetically coupled resonant WPT systems with multiple sources and loads. Taking the three-port system as an example, the system architecture and specific circuit topology of power and information transfer circuits are demonstrated, and the corresponding equivalent circuit models are built to analyze the power transfer characteristic and information transfer gain. Meanwhile, key parameters to achieve the required information transfer gain are designed, and the power and information crosstalk is discussed. A prototype with three ports and the rated power of 400 W is fabricated in the laboratory, and the validity of the proposed methodology is verified by experimental results.

Based on the analysis of the magnetic field distribution characteristics around transmitting coil, this paper proposes a novel coil arrangement method for multi-load magnetic coupling resonant wireless power transfer (MCR-WPT) systems. By maintaining specific radial and angular offsets between the receiving and transmitting coils, the receiving coils are positioned in regions with higher magnetic flux density, and their planes are approximately perpendicular to the magnetic flux lines. This configuration effectively increases the mutual inductance between coils and improves overall transfer efficiency. Experimental results show that when the radial offset distance is 12 cm and the rotation angle is 60°, the system achieves a maximum transfer efficiency of 81.49%. The proposed approach provides a useful design reference for optimizing coil arrangements in multi-load WPT systems.

Solar unmanned aerial vehicles (UAV) are usually confronted with harsh operating environments, and the photovoltaic (PV) converters used to power the solar UAV become more vulnerable. Hence, the effective fault monitoring and post-failure treatment for PV converters are required. This paper presents a fault diagnosis and reconfiguration scheme for distributed PV converter array consisting of synchronous rectification (SR) Boost converters, including a fault diagnosis method for switches by detecting the inductor current and the voltage across switches, and a fault reconfiguration scheme for PV converter array which uses the switches matrix to remove the fault module. The validity of the scheme is verified through experiments on the prototype of the PV converter array.

At present,the study on magnetic coupling resonance-wireless power transmission(MCR-WPT)mainly fo-cuses on two forms of single-transmitting multi-load stationary and single-transmitting single-load rotating.Based on the analysis of a system in a single-transmitting low-speed rotating multi-load state,a single-transmitting multi-load system is established and analyzed theoretically,and the multi-load receiving coil in a stationary state is simulated using COM-SOL.The stationary and rotating states are used to form a contrast experiment to analyze the effect of the rotating receiv-er on the transmission efficiency of the MCR-WPT system,and the changes in the system transmission efficiency in the low-speed rotating state are discussed.Results show that under the low-speed rotating three-load,the system can main-tain a stable power output,the transmission efficiency under single load can reach 23.26%,and the total transmission ef-ficiency can reach 69.768%,indicating little influence of low-speed rotation on the transmission efficiency.

Multi-port simultaneous wireless information/ power transfer (SWIPT) technology can not only realize power transfer between multiple sources and loads, but also realize the transmission of control information and the feedback of electrical signals. The modulation scheme is an important factor to determine the data transfer rate in SWIPT applications. For this purpose, a 4-pulse amplitude modulation (4PAM) modulator is presented in this paper, along with the circuit design and the related waveforms. The proposed modulator is capable of transmitting two bits of data simultaneously into a single symbol and proved to achieve a data transfer rate up to 1.25Mbps at 5MHz carrier, which can be potentially used in multi-port SWIPT applications.

Modular series-parallel (MSP) systems with the superiority of easy scalability and high reliability, are widely used in high-power applications. In this paper, the MSP system configuration is implemented in wireless power transfer (WPT) applications. However, the current sharing issues of MSP WPT systems have not been investigated thoroughly. Especially the power transfer characteristics are more complex considering the cross-coupling between coils. Therefore, this paper focuses on the current sharing issues of the dual modular input-parallel-output-parallel (IPOP) configuration with LCC compensated sub-modules. The fundamental harmonic analysis method is used to obtain the system transfer characteristics of modular WPT systems, and then the current imbalance mechanism under four kinds of parameters mismatches is revealed. The correctness of the analysis is verified through experiments on a dual-module IPOP system.

This article proposes a modular stacked multiport wireless energy interconnection (WEI) system with a virtual ac bus for multisource and multiload wireless power transfer (WPT) applications, which has the following advantages. 1) It can serve as an interface for WPT among multiple sources and loads. 2) Bipolar coils are adopted to eliminate the undesired cross-coupling among multiple coils, which simplifies the complexity of system modeling and power flow control. 3) The relay coil with constant current characteristics is introduced as a virtual ac bus, from which the derived multicoil structure provides the bidirectional channel for power transfer between any two ports. 4) System applicability and scalability are greatly enhanced due to the modularization of coils, power converters, and compensation circuits. For power flow control, the hybrid phase-shifted control method matched with the WEI system is applied, in which the power flow direction is determined by the external phase-shifted angles between ports, whereas the power values are regulated by the internal phase-shifted angles. Furthermore, the peak value of the current of the virtual ac bus, as an intermediate control variable, is controlled to be constant; thus, distributed control can be further realized. Finally, a four-port experimental prototype was built and experiments were carried out under different operating conditions. The efficiency curves and loss distribution, as well as the tolerance analysis of coil misalignments, are given. From the experimental results, the effectiveness of the proposed system architecture and its power flow control strategy is verified.

For the magnetically coupled resonant wireless power transfer (MCR WPT) applications with high-power level and medium-range distance, the low coupling coefficient brings severe challenges to the system efficiency and reliability, as the coil loss and the voltage/current stress on compensation components are both considerable; meanwhile, the high operating frequency that contributes to improve the power density will result in high switching loss and related electromagnetic interference. In this article, a parameter design methodology for high-power and medium-range-distance MCR WPT applications was proposed to achieve high system efficiency. The accurate time-domain system model was built to obtain the relationship among voltage/current stresses on the compensation components, zero-voltage-switching (ZVS) conditions of power switches and system parameters. The key parameters, including the switching frequency, the coil self-inductance, and the compensation inductance, are designed to realize wide-range ZVS and reduce voltage/current stresses. Double-layer coil configuration was adopted instead of the traditional single-layer coil to reduce coil losses, and the series compensation capacitors in TX and RX coils were split to achieve current sharing between double-layer coils. Meanwhile, the LCCL-TT compensation network was used to achieve the optimal load and maximize the system efficiency. Finally, a 1-kW MCR WPT prototype within 100-cm transmission distance was implemented in the laboratory for experiments, and the system efficiency under the rated condition is 80.62%.

针对磁耦合谐振无线电能传输(MCR WPT)系统中负载接入数目对于系统整体输出功率与传输效率的影响问题,设计了一种带有中继线圈的多载接入式MCR WPT系统,通过控制系统中负载线圈的接入数目,研究系统的输出功率与传输效率的变化.当系统中接入负载数目增加时,单个负载的传输效率与传输功率逐渐下降,但系统总的输出功率与传输效率逐渐上升,并随着负载数目增加至8个以后,系统的输出功率与传输效率达到饱和,饱和点系统的输出功率为4.51 W,传输效率为79.12％.

负磁导率超材料作为超材料中的一个研究热点,能显著提高磁耦合谐振式无线电能传输系统的传输性能.因此,分析磁耦合谐振式无线电能传输系统的电路模型,设计基于系统工作频率为10MHz的负磁导率超材料,对其进行数值仿真,提取其磁导率,并研究其在磁耦合谐振式无线电能传输系统中,沿两线圈轴线方向不同位置下对系统传输性能的影响.经过仿真和实验验证,当超材料板在接收线圈附近时,能够显著提高系统的负载功率和传输效率.

High-power magnetically coupled resonant (MCR) bidirectional wireless power transfer (BWPT) within long distance can be potentially used in various applications. However, the coupling between transmission coils will drastically decrease with the rise of distance to diameter (d-D) ratio, and voltage/current stresses on resonant components tend to increase apparently, which further deteriorate the system efficiency and stability. In this paper, the relationship between the coupling coefficient and the d-D ratio in high-power BWPT systems is analyzed by mathematics methods. The correlations of transferred power and system efficiency with d-D ratio are presented consequently. The scheme of coils magnetic concentration and double-layer coils in parallel is adopted to improve the system performance. The theoretical analysis is demonstrated by the experimental results of a 2kW prototype, and the system efficiency is improved from 70.7% to 77.47% under the d-D ratio of 1 (300mm-300mm).

Nowadays, the magnetically coupled resonant (MCR) wireless power transfer (WPT) system are mostly the single-source or single-load systems that operate at “one to one” mode. With the increasing number of electrical equipment and types of input sources, the “one to one” mode cannot meet the application requirements. Therefore, the "one-to-many" and "many-to-many" WPT become increasingly important. In this paper, a three-port MCR wireless energy router (Wi E-Router) architecture with dual sources and dual loads is investigated in detail, which allows power transfer among dual sources and dual loads wirelessly. The equivalent circuit model of the system is built to analyze its transfer characteristics. Moreover, an effective power management strategy for a variety of input power cases is proposed. Finally, the theoretical analysis is validated by the experimental results from a 600 W prototype.

For multi-source and multi-load wireless power transfer (WPT) applications, a novel architecture of modular stacked multi-port wireless energy interconnection system (WEIS) with virtual AC bus is presented in this paper, which has following advantages: 1) it can serve as the interface among multiple sources and multiple loads; 2) bipolar coils are applied to eliminate the cross-coupling among multiple coils; 3) the relay coils with constant current characteristics are adopted as a virtual AC bus, and the system power distribution is greatly simplified by the proposed phase-shifted control method; 4) the modularization of power converters, coils and compensation networks greatly enhances the system applicability and scalability. A four-port WEIS prototype with the rated power of 2kW was built, and experiments were carried out for typical operation modes including single-source three-load mode and dual-source dual-load mode, which verified the effectiveness of the proposed system architecture.

Multi-module series-parallel (MMSP) power systems have the superiority of easy scalability and high reliability, and is the prospective candidate for high-power conversion. In this paper, the MMSP configuration is implemented in wireless power transfer (WPT) applications. However, the voltage and current sharing issues have not been analyzed precisely in existing researches. To obtain the inherent principle of voltage and current sharing in the MMSP WPT system, the dual-module series-parallel WPT systems with four configurations are studied as examples. By the fundamental harmonic analysis, the characteristics of a WPT module are obtained, and then the imbalance mechanism of voltage and current under four kinds of parameters mismatches are revealed. The results of circuit simulation verify the correctness of the theoretical analysis.

Recently, LCCL-LC compensated magnetically coupling resonant wireless power transfer (MCR WPT) systems are widely used to achieve the constant and load independent output voltage performance compared with other counterparts. To analyze the zero-voltage-switching (ZVS) conditions of the system, the fundamental harmonic approximation (FHA) model is usually utilized, but the analytical results are not accurate due to the neglect of high order harmonics. In this paper, a time domain model considering high order harmonics was proposed to solve this issue. Based on that, a method of modulating the compensated capacitor was put forward to realize ZVS within the full range of loads. However, this method will cause the system to deviate from its full resonance state and further deteriorate the system efficiency. To enable the system to realize ZVS in the full resonance state, the improved optimization method to modulate the compensated inductor was proposed. Finally, a 1kW prototype was built and a series of experiments were carried out, the experimental results demonstrate the effectiveness of the parameters optimization for ZVS realization. The overall efficiency enhancements by the two proposed methods are 0.47% and 1.31% respectively.