Nowadays, work on Wireless Power Transfer (WPT) systems with dual active bridges is attracting great attention due to their low conduction losses, power regulation, load transformation and reactance compensation. However, in these studies limitations such as overall analysis, design and realization techniques of the system were not considered properly. To address the aforementioned issues, this paper presents a detailed analysis, design and realization of a Series-Series (SS) WPT system with dual active bridges, which will improve the overall performance. Three independent Phase Angles (PAs) have been analyzed and designed in this study, one PA on the primary side and the other two PAs on the secondary side. This Multiple Degrees of Phase Control (MDPC) method can achieve additional reactance compensation, load transformation and output regulation simultaneously. To realize the proposed method in practice, key implementation techniques have been investigated in detail, including additional reactance estimation, mutual inductance estimation, phase detection and synchronization. The feasibility and effectiveness of the proposed system is verified through simulation and experimental results.

Aeromonas species often cause disease in farmed fish. In the present study, dominant bacteria were isolated from diseased crucian carp (Carassius auratus gibelio). Based on this, a bacterial isolate was tentatively named CFJY-623. This isolate was identified as Aeromonas veronii based on analysis of its morphological, physiological, and biochemical features, as well as 16S rRNA and gyrB gene sequences. Six virulence genes related to pathogenicity including aerolysin, cytotonic enterotoxins, elastase, glycerophospholipid: cholesterol acyltransferase, lipase, and serine protease were identified in this A. veronii isolate. The median lethal dosage (LD50) of the CFJY-623 isolate for crucian carp was determined as 1.31 × 10 7 CFU/mL. Artificial experimental infection showed that the CFJY-623 isolate caused considerable histological lesions in the fish, including tissue cell degeneration, necrosis, and inflammatory cell infiltrating. Drug sensitivity testing showed that the isolate was susceptible to aminoglycosides, carbapenemes, and nitrofurans. Exploring its growing features showed that this isolate exhibited a high level of environmental adaptability. These results provided a scientific basis for the identification of A. veronii and treatment for fish infected by this pathogen.

Recently, efficiency improvement of wireless power transfer (WPT) systems has been the focus of research. Conventional methods of DC-DC converters are employed for load modulation to achieve high efficiency over large variations in mutual inductance and load. However, these additional circuits degrade the performance due to their inherent losses. To address this problem, this study presents a dual-side phase shift control method for load modulation and voltage regulation in a compact WPT system. The key features of the proposed work are: attaining load modulation and voltage regulation with reduced size of the system; elimination of communication between active bridges and simple control logic. Mathematical expression of equivalent resistance versus the phase shift angles (PSAs) is deduced and the optimal PSAs for maximum efficiency are presented. Utilisation of local control, stability analysis and fault detection method are included. MATLAB/Simulink simulation and experimental results are carried out to validate the proposed method.

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