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The cascaded H‐bridge (CHB) converter can achieve rich functions, such as active rectification, active power filtering, distributed energy storage, etc. The control of the CHB converter is a multiobjective optimization problem. Finite control set model predictive control (FCS‐MPC) is an effective method developed in recent years to solve this problem. However, because of the large amount of calculation, traditional FCS‐MPC cannot be directly used to control the multilevel CHB converter. It is also difficult to tune the weighting factors in traditional FCS‐MPC. To solve these problems, this paper proposes an improved sequential MPC (IS‐MPC) method for the CHB converter. The proposed method divides the control objectives of the CHB converter into different layers according to their priorities and the control degrees of freedom of each layer can be adjusted according to the system state. Simulation and hardware‐in‐the‐loop (HIL) implementation on a three‐phase 7‐level CHB converter shows that the proposed method can effectively control the ac current and submodule voltage of the CHB converter and reduce the switching loss. Moreover, it significantly reduced the calculation burden of traditional FCS‐MPC, and the use of the weighting factors is also avoided. © 2024 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

This paper deduces the quantitative relationship between the flux vectors and the power of power winding (PW) in brushless doubly‐fed reluctance generator (BDFRG). On this basis, the direct power control (DPC) theory of BDFRG is established, which makes up the deficiency that the DPC theory of BDFRG is only based on qualitative analysis in the existing literature. The power derivative expression is derived for accurately analyzing the effect of voltage vector of control winding (CW) on the power of PW, concluding that the control effect of DPC is related to the operation point of a BDFRG. The number of basic voltage vectors of CW connected with two‐level converter is limited, resulting that under some operation conditions, a BDFRG controlled by DPC could present a time interval where the power cannot be controlled satisfactorily. Therefore, the space vector modulation‐based direct power control (SVM‐DPC) strategy of BDFRG is proposed, which can solve the above problem and fix the switching frequency. Experimental results prove the correctness of the elaboration and the proposed method. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Particle swarm optimization (PSO) is a popular optimization technique known for its simplicity and effectiveness. This paper introduces a variant that achieves a better balance between exploration and exploitation, named DiPSO. DiPSO incorporates a novel strategy based on trends in mean distance between individuals for local exploitation control. Experiments on 29 benchmark functions demonstrate that DiPSO consistently outperforms the state‐of‐the‐art variant of PSO. Convergence analysis reveals that DiPSO achieves faster convergence and superior solutions. These results highlight the effectiveness of DiPSO in solving optimization problems. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The auxiliary resonant snubber‐based converter (ARSC) has the advantages of low dead‐time effect and low switching loss. However, the auxiliary switches suffer from high reverse recovery loss and high reverse recovery current in high‐switching frequency application. Thus, the ARSC with saturable inductor is proposed to solve the problem above. In this paper, the operating principle of ARSC with saturable inductor is analyzed, and the duty cycle operating range that can realize ZVS in the full load range is deduced. The reverse recovery model of the auxiliary switching device body diode is established to analyze the circuit parameters' influence. Then, the influence of the saturable inductor on the reverse recovery peak current and reverse recovery loss is analyzed. Based on the analysis results, the saturable inductance parameters are designed. Finally, based on the experimental platform of the ARSC, the effectiveness of the proposed method is verified. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

A local immunization strategy, which is effective in huge no‐scale network, is proposed in the paper. When there is an outbreak of virus in network, vaccinating limit nodes can reduce the damage of virus by preventing the propagation. Immunization strategy, which has been a hot topic for years, manages to choose the proper nodes to vaccinate. However, with the modern network growing large rapidly, the classic immunization strategies, such as degree‐based strategies and betweenness‐based strategies, will face the efficiency problem and accuracy problem. To solve the problem, we have pro‐posed a local immunization strategy, which performs effectively in huge no‐scale network. Firstly, we train an unsupervised graph neural network to get the embedding of nodes. Then with the help of node's embedding, we find the nodes exposed to virus spreader most severely and choose them as the vaccinated target. The calculation of node's exposure is local and fast, and it can depict the node's suspicious exposure to the virus from the global view of the network, which makes our immunization strategy approximate the global optimal solution. In addition, the vaccinating targets are calculated timely according to real‐time distribution of virus spreaders, by this way, our strategy is adaptive to the fast changes in the propagation of virus. At last, we refine the time complexity to make our strategy practical in huge network. Compared with current method, our network immunization strategy shows privilege in the simulation experiment. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In traditional power systems, the positive sequence fault component (PSFC) based criteria is often used to identify the fault directions. If the PSFC impedance angle of the inverter‐interfaced distributed generator (IIDG) is between 0 and 90°, the traditional PSFC‐based criteria will remain applicable in active distribution networks (ADNs). However, due to the diversity of the IIDG fault control mode and the uncertainty of the positive sequence voltage variation caused by faults, the PSFC impedance angle of IIDG is difficult to determine. To solve this problem, this paper proposes a two‐stage fault control scheme for IIDG. At different stages, IIDGs select different power references to meet different requirements. In the first stage, the PSFC impedance angle of IIDG is fixed to a given value, thereby maintaining the applicability of the PSFC‐based criteria in ADN. The detailed power reference calculation method of IIDG is given for this stage. In the second stage, IIDGs can select different fault control modes to support the fault voltage flexibly. By using the proposed two‐stage IIDG fault control scheme, the protection devices can accurately identify the fault direction in ADNs, which is verified by the MATLAB simulation results. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

A new image dehazing algorithm based on adaptive sky region is proposed in this paper, which shows good fidelity in sky region and satisfying visual effect in non‐sky region. For robust sky segmentation, we propose a rough‐to‐fine method that can make a balance between efficiency and accuracy. Considering distribution of haze is inconsistent, we divide the input image into three parts and calculate their atmospheric lights respectively. To solve the problem of invalid dark channel prior, we make an improvement for the transmission estimation. Finally, image fusion is taken as a post processing that can solve the problem of partial darkness and ensure a visual pleasing result. The experimental results for both synthetic and natural hazy images demonstrate that our algorithm performs comparable or even better results than the state‐of‐the‐art methods in terms of various measurement indexes, such as the PSNR, SSIM, and so forth. Besides, the proposed algorithm can be also applied in FPGA platform due to the optimized performance. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

At present, intermittent control is a main method to solve the problem of pumping output voltage with light load of LLC resonant converter, which can not only solve the problem of high pumping output voltage, but also, to a certain extent, improve the efficiency of light load to a certain extent when converter is operating. However, in extremely light‐loading, especially in no‐ loading, with the intermittent cycle increasing and the low‐frequency ripple being introduced, which cannot meet the demand of high‐quality output voltage, and is not conducive to the converter's stable operation. Due to the extremely small power transferred by the converter, in this case, efficiency is not the main factor considered. In this paper, a voltage regulation strategy based on energy feedback is proposed for LLC resonant converter in extremely light‐loading. The output voltage is controlled by adjusting the feedback energy to the source. Compared with the uncontrollable burst off mode of the intermittent control, the proposed control method can effectively improve the output voltage quality due to the controllability in voltage drop mode and the independence from the load. It also can eliminate low frequency ripple and extend battery charging life. The output voltage ripple is minimized by optimizing the duty cycle and the phase shift angle. The correctness and feasibility of the proposed method are verified by experiments. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]