This paper proposes an AC bus-based distributed battery management system, where the secondary windings of modular equalizers are series-connected. The proposed system enables rapid and flexible power balancing from any cells to any cells. The modular equalizers are designated as either active or inactive, depending on their involvement in power balancing. By employing loosely coupled transformers and resonant networks, it ensures decoupling between active and inactive equalizers, allowing balancing to occur exclusively among unbalanced cells and thereby improving efficiency. The distributed control strategy enables each equalizer to determine its power target based on SOC, improving balancing accuracy. This target is tracked via locally generated control signals, eliminating the need for external synchronization or global timing, thereby enhancing system scalability. Finally, simulation results from a four-equalizer prototype demonstrate the effectiveness of the theoretical analysis.

Talkative Power Conversion (TPC) is a cost-effective communication solution for DC microgrids, enabling power converters to transmit both power and data simultaneously by embedding data into their output voltage ripples. However, due to its broadcast nature, TPC is susceptible to eavesdropping. To address this security vulnerability, this paper proposes a novel physical-layer data carrier encryption strategy. The embedded data ripple generated by the transmitter is mixed and encrypted with a noise ripple generated by the receiver, making unauthorized interception infeasible. In addition, closed-loop impedance models are derived to construct and analyze the small signal model of the proposed system. Finally, a DC microgrid based on bidirectional buck-boost converters is implemented, and theoretical analysis is validated through simulation results.

This paper proposes a transformerless T-type modular multilevel DC-DC converter (T-MMDC) with quasi-square wave (QSW) modulation for high-voltage direct current (HVDC) grid applications. The proposed topology employs asymmetric three-arm configurations to achieve direct power conversion without isolation transformers. Analytical models are developed to characterize the inherent power flow dynamics and energy balance constraints. Operational principles under QSW modulation are systematically investigated, including derivations of voltage-current relationships and commutation mechanisms. A hierarchical control framework integrating energy balancing and commutation strategy is designed to ensure stable power conversion. Comprehensive simulations of a 500MW, 320kV-100kV system demonstrate stable operation with efficient energy transfer. Experimental validation using a 5kW, 750V-250V prototype confirms the methodology's effectiveness under practical non-ideal conditions. Results substantiate the proposed topology as a viable solution for utility-scale renewable energy integration and multi-voltage-level transmission in HVDC networks.

In wireless power transfer (WPT) systems, effective communication between the transmitter and receiver is crucial for precise control and system monitoring. To address this need, simultaneous power and information transfer (SWPIT) has been extensively studied. However, SWPIT implementations often require additional coils or circuits, which complicates the overall system. This work presents the design and numerical experiments of a minimal SWPIT system. The auxiliary modulation circuits are simplified using phase shift control in the inverter, while multi-carrier modulation can be embedded to enhance frequency band utilization. Similarly, auxiliary demodulation circuits are simplified by leveraging the frequency-mixing effect in the rectifier. The proposed minimal SWPIT method is adaptable across diverse compensation networks. The key transfer characteristics of the compensation network are cloned in the information transmission, enabling load-independent communication. Simulation results confirm the theoretical analysis, demonstrating the transfer characteristics and elasticity of the minimal SWPIT system.

The grid-forming (GFM) converter serves as a crucial link between the grid and generation in large-scale power-generation systems. However, unintentional grid faults risk the transient stability of GFM converter, which severely impacts the reliability of systems. This paper introduces the critical parameter characterization for power synchronization, which can stabilize the GFM converter over grid faults. The foundation of this work lies in the analysis of the effect of the crossing coupling between the power loops on transient stability. It reveals that, the transient terminal voltage drop generated by the crossing coupling will give rise to jeopardize the transient stability but can be alleviated by adjusting droop-control parameters. This insight facilitates the derivation of the critical parameters for a stable transient operation. With the derived parameters, the GFM converter can operate stable under grid faults. Finally, experiments are conducted to confirm the theoretical expectations.

The communication of the Battery Management System (BMS) is crucial to the regular operation of the BMS. This paper proposes a communication-integrated battery equalization strategy based on bidirectional flyback converters. In comparison to the strategies currently in use, the proposed strategy sends data by modulating the drive signal of the switching devices in the bidirectional flyback converter rather than using a separate signal transmission circuit, which reduces hardware complexity and lowers cost. Additionally, the receiver can demodulate data by analyzing the voltage ripple of the input and output ports in the bidirectional flyback converter. In this paper, an experimental system prototype with three bidirectional flyback converters is built. The experiment achieves an 8.33kb/s communication rate and verifies the feasibility of the proposed strategy.

Simultaneous wireless power and data transmission is a novel topic in wireless electric vehicle (EV) charging. The data transfer sharing the existing power coils is an attractive method compared to the conventional far-field communication technologies. The frequency division multiplexing (FDM) technique can achieve the data transfer without interupting the power transfer. This paper proposes a general method to construct communication channels that fit the FDM technique on inductive power transfer (IPT) topologies. According to this method, nine kinds of communication channel structures can be derived for the four basic compensation topologies. The high transfer gain of data carrier is achieved without changing the power carrier transfer path. The communication interference from the power harmonics can be effectively suppressed. The proposed communication channel is simulated and verified by experiments.

In wireless electric vehicle charging, the relative position of the primary and secondary coils has a significant impact on the transfer power and efficiency. In this paper, a magnetic coupling positioning method using simultaneous power and data transfer is proposed. The proposed positioning method employs four auxiliary coils placed on the primary coil to position the secondary coil. The positioning process is presented, which can be conducted both online and offline. The optimum locations of auxiliary coils are analyzed and simulated. A prototype is built up to verify the proposed method, and the experimental results are presented and discussed.

In this paper, a separation test method for eliminating the effects of different current densities on the bond wires is proposed. The separation test method makes it possible to study the effect of different current density on the fatigue damage of bond wires without changing the temperature swing and average temperature during the test. By analyzing the output characteristics of the linear region of MOSFET, the constraint relations among the gate voltage, on-state voltage drop and junction temperature are revealed in this paper. The one-to-one correspondence between gate voltage and conduction power loss can be used to adjust the current density under fixed temperature swing and average temperature. The commercial Silicon Carbide (SiC) MOSFET modules are tested to experimentally verify the proposed method. Finally, the effectiveness of proposed test method is validated by the experimental results.

The energy Internet concept has been considered as a new development stage of the smart grid, which aims to increase the energy transmission efficiency and optimize the energy dispatching in time and space. Energy router is a core device in the energy Internet and it connects all the devices together into a net structure and manages power flows among them. The research work presented in this paper described the energy router's structure and function expectations from the network perspective, and improved the existing energy router design. Open shortest path first (OSPF) protocol and virtual circuit switching mode are referenced from the Internet in the energy local area network (e-LAN) design. This paper proposed a design of an energy routing algorithm based on graph theory in an e-LAN. A lowest cost routing selection algorithm is designed according to the features of power transmission, and a source selection and routing design algorithm is proposed for very heavy load conditions. Both algorithms have been verified by case analyses.

This paper introduces an isolated high voltage gain DC-DC converter, which can achieve high output voltage and large power level with hybrid connection of modular active-clamping current-fed push-pull(CFPP) converters. Thanks to the modularity, the voltage stress of semiconductor devices and the power rating of magnetic components are low. In addition, zero-voltage-switching operation is achieved for all switches and thus low EMI noise can be obtained. Furthermore, the secondary current of different CFPP converters in the same column is auto-balanced, contributing to reduced control complexity. With redundant rows and columns, the converter can remain normal operation under fault state. In the paper, the operation and analysis of the converter are illustrated in detail and the simulation results are demonstrated to verify its advantages.

Selection of suitable energy solutions for a rural location seems complicated while addressing multiple and simultaneous technical, social, economic and environmental traits. Even with achievements of theoretical progress towards binding their synergies, only a handful of approaches exists for well-designed multiple objective frameworks considering rural electrification. For a successful implementation of rural electrification project for any demography of world, the social criteria play a very crucial role. Decision analysis involving technical, financial, social and environmental aspects becomes more diverged and challenging. However, Multi-Criteria Decision Analysis Tool (MCDA) has arisen as a solution to diverse criterion and differing views. A MCDA method facilitates decision processes that are logically difficult, participative and translucent, for energy planning. In this paper, a methodology framework incorporating decision analysis techniques has been presented to evaluate and determine a suitable energy system for rural electrification with a perspective to sustainable development. Technically mature, commercially available and government regulated energy sources were considered to generate the possible alternatives. A total of twelve alternatives were proposed; the first six in a Compact Centralized Off Grid Generation and another six as Compact Centralized Grid connected systems. Solar, wind, diesel generator was considered as energy sources along with battery as storage.

For low power dielectric barrier discharge (DBD) used in small-size material treatment or portable devices, high-step transformer parasitic capacitance greatly influences the performance of the resonant converter as it is of the same order of magnitude as the equivalent capacitance of DBD load. In this paper, steady-state analysis of the low power DBD is presented, considering the inevitable parasitic capacitance of the high-step transformer. The rectifier-compensated first harmonic approximation (RCFHA) is applied to linearize the equivalent load circuit of DBD at low frequency and the derived expressions are accurate and convenient for the analysis and design of the power supply. Based on the proposed linear equivalent load circuit, the influence of transformer parasitic capacitance on the key parameters, including the frequency range and the applied electrode voltage, is discussed when the power is regulated with pulse frequency modulation (PFM). Also, a design procedure is presented based on the derived expressions. A prototype is constructed according to the design results and the accuracy of the design is verified by experimental results.

An optimized modulation is proposed for the bidirectional DC-DC converter based on the full-bridge/push-pull circuit. With the proposed strategy, the zero-voltage-switching (ZVS) range of the lagging-leg switches in the conventional full-bridge topology can be extended. Moreover, severe voltage overshoots across main switches caused by the leakage inductance of the transformer in the current push-pull circuit are suppressed. Furthermore, the modulation is unified for both the buck mode and the boost mode, which is easy to realize compared with the conventional methods. In addition, no auxiliary circuits are employed, resulting in low cost and small volume. Detailed analysis and design of the proposed modulation are described. The simulation results validate the operation principle and a \kW prototype is built to show the effectiveness of the proposed strategy.

The modeling of switching loss in semiconductor power devices is important in practice for the prediction and evaluation of thermal safety and system reliability. Both simulation-based behavioral models and data processing-based empirical models are difficult and have limited applications. Although the artificial neural network (ANN) algorithm has often been used for modeling, it has never been used for modeling insulated gate bipolar transistor (IGBT) transient loss. In this paper, we attempt to use the ANN method for this purpose, using a customized switching loss test bench. We compare its performance with two conventional curve-fitting models and verify the results by experiment. Our model is generally superior in calculation speed, accuracy, and data requirement, and is also able to be extended to loss modeling for all kinds of semiconductor power devices.