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In the cascaded H - bridge multilevel SVG (Static Var Generator), the inherent structural characteristics of the H - bridge lead to the presence of secondary ripple in the DC side capacitor voltage of the angular cascaded SVG, and the voltage ripple affect the degree of compensation of power quality and even lead to system dysregulation. In order to suppress the secondary ripple of the voltage on the H - bridge DC side of the angular cascaded SVG, this study proposes a design solution for the angular cascaded H - bridge multilevel SVG based on Boost type active power decoupling. The APD (Active Power Decoupling) circuit separates fluctuating power and stable power from each other and uses energy storage elements to absorb fluctuating power, which weakens the voltage ripple on the DC side of the H-bridge. The simulation platform was built and simulated using MATLAB/Simulink software. The simulation results show that the angular cascaded H - bridge multilevel SVG based on Boost type active power decoupling can effectively suppress the secondary ripple of the voltage of the DC side capacitor. [ABSTRACT FROM AUTHOR]

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To increase the DC voltage utilization ratio of traditional five-phase voltage source inverter ( VSI), the five-phase Z-source VSI topology, which is based on the traditional five-phase two-level VSI, is proposed. This inverter exploited the boost characteristic of the Z-source network to increase the DC voltage utilization ratio and the voltage transfer ratio. To reduce the harmonic waveform of the output voltage, optimized space vector modulation scheme was employed. By minimizing the synthesized vector in the third-order harmonic subspace, harmonic can be greatly reduced. The proposed five-phase Z-source inverter was studied by simulation, and experiment was carried out on digital signal processor ( DSP) controlled platform. The feasibility of the inverter and the effectiveness of the modulation scheme was proved by simulation and experimental results. Finally, five-phase Z-source VSI can improve the DC voltage utilization ratio, and it can be applied in the field where DC voltage is limited. [ABSTRACT FROM AUTHOR]

According to the current situation, experimental devices for power technology in colleges and universities are large, poor flexibility and high voltage level. To solve these problems, we developed a digital power experimenters kit based on the concept of pocket laboratory experiment. TI C2000 Launchpad was used as core controller. The kit also applies TMS320F28027, system board, LCD, and has a compact structure, a small size. It has functions of Buck, Boost, Cuk and Sepic. It can do the open-loop regulator experiments, peak current control experiments and dual-loop control experiment. It is portable and convenient, especially, is suitable to students in extracurricular activities and innovation competition. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the safety and immunogenicity of one booster dose of inactivated hepatitis A vaccine in young adults. Methods: The subjects were selected from participants in the clinical trial of immunogenicity of inactivated and attenuated live hepatitis A vaccine in young adults. Eligible subjects were those who had received one dose of inactivated or attenuated hepatitis A vaccine, could be contacted and were sero-negative before primary vaccination. All qualified subjects were immunized with one booster dose of inactivated hepatitis A vaccine. The blood samples were collected before booster dose vaccination and 28 days after the immunization. Anti-HAV antibody titer ≥20 mIU/ml was considered to be sero-protected against hepatitis A virus. Results: The GMCs in the inactivated HAV vaccine group and attenuated live vaccine group before booster dose vaccination were 70.80 mIU/ml and 50.12 mIU/ml, respectively, and the sero-protection rates were 94.7 % and 65.0 % , respectively. After the vaccination of the booster dose, the sero-protection rates in both groups were 100.0 % , and the GMCs were 2 816.09 mIU/ml and 2 654.55 mIU/ml, respectively. Conclusion: The GMCs and sero-protection rates of anti-HAV antibody in young adults declined after three years of the primary vaccination. However, the higher GMC and sero-protection rate were observed in the inactivated vaccine group than in the attenuated live vaccine group. Significant increases of GMC levels were observed in both groups after one booster dose vaccination.