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Aiming at the problem that the output voltage of relay inductive coupled power transfer (ICPT) system is susceptible to changes due to the influence of system load changes, frequency perturbations, and input voltage fluctuations, an H∞ mixed sensitivity robust control method is adopted to relay ICPT system to regulate the output voltage. First, the working principle of the relay ICPT system is analyzed. Then, the GSSA model of the relay ICPT system is established. By constructing the S/R/T mixed sensitivity function, a suitable weighting function is selected from the frequency domain perspective and converted into H∞ standard control problem to get a robust controller. Finally, an experimental platform is built to verify the control effect of the controller on the system output voltage. Experimental results show that the designed controller in this paper stabilizes the system output voltage and obtains good tracking performance, suppression parameter perturbation performance, anti-interference performance, and improves system robustness simultaneously. [ABSTRACT FROM AUTHOR]

Compared with the single-phase wireless power transfer systems, the three-phase wireless power transfer systems have the advantages of large transfer power, high position offset tolerance, and small output ripple, etc., which have been widely used for high-power application. For a three-phase rail-type dynamic wireless power transfer system, the interphase cross-coupling mutual inductance, will lead to three-phase unbalance, difficult modeling and analysis. So, a new type of three-phase rail-type magnetic coupling structure is proposed and optimized. Firstly, a magnetic coupling structure for a three-phase rail-type dynamic wireless power transfer system is proposed. Secondly, the physical principle and mathematical tools are used to calculate the primary and secondary equivalent parameters of the system, and a fully decoupled equivalent mathematical model of the system is established. Thirdly, based on the model, the output characteristics of the system such as power and efficiency are analyzed. Finally, an experimental platform for a 1 kW three-phase rail-type dynamic wireless power transfer system is built to verify the theoretical analysis. The experimental results show that the magnetic coupling structure proposed in this paper can well solve the problem of system imbalance caused by interphase cross-coupling mutual inductance, and improve the power and efficiency of the system. [ABSTRACT FROM AUTHOR]

The problem of charging unmanned aerial vehicles (UAVs) is an important application area for wireless power transmission (WPT). However, the flight characteristics of UAVs make it difficult for the traditional single-coil coupling mechanism to ensure alignment between the transmitting and receiving ends. It also has poor anti-skewing performance and a cumbersome optimization process, which ultimately decreases the efficiency of charging UAVs. To address this problem, this paper takes the 2 × 2 square coil array as research object, analyzes the distribution characteristics of the axial magnetic field at a specific height, proposes a "cross" compensation structure, and adopts genetic algorithm to optimize the side length and turns of the compensation coil. The goal is to significantly improve the axial magnetic field uniformity in the charging area and reduce the degree of magnetic field leakage. Finally, the effectiveness and superiority of the proposed "crossover" compensation structure and its optimization method are demonstrated through the construction and testing of the system experimental platform, which significantly improves the anti-offset performance and transmission efficiency of the WPT system. [ABSTRACT FROM AUTHOR]

The DC short-circuit fault occurring on the overhead line endangers the modular multilevel converter based high voltage direct current (MMC-HVDC) grids. An optimized protection coordination (OPC) strategy with a global fault current limiting control is proposed to limit the DC fault current in this article, which can suppress the rising rate of the global fault current, and at the same time, the fault area can be identified quickly and the relevant DC circuit breakers can be pre-operated. To realize the OPC strategy, a rapid fault identification method based on the current change rate and Pearson correlation coefficient is designed. The proposed rapid protection strategy can decrease the peak value of DC fault current by reducing the rising rate of current and shortening the protection time. Simulation and experimental results verify the effectiveness of the proposed strategy under both balanced and unbalanced grid-side voltage conditions. The adoption of the proposed control is beneficial for MMCs to safely ride through DC short-circuit fault in a continuous operation manner. [ABSTRACT FROM AUTHOR]