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Digital Control of Secondary Active Clamp Phase-Shifted Full-Bridge Converters
Yanbo Che,Yage Ma,Shaoyun Ge,Dong Zhu 전력전자학회 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.3
A DSP-based self-adaptive proportional-integral (PI) controller to control a DC-DC converter is proposed in this paper. The full-bridge topology is adopted here to obtain higher power output capability and higher conversion efficiency. The converter adopts the zero-voltage-switching (ZVS) technique to reduce the conduction losses. A parallel secondary active clamp circuit is added to deal with the voltage overshoot and ringing effect on the transformer’s secondary side. A self-adaptive PI controller is proposed to replace the traditional PI controller. Moreover, the designed converter adopts the constant-current and constant-voltage (CC-CV) output control strategy. The secondary active clamp mechanism is discussed in detail. The effectiveness of the proposed converter was experimentally verified by an IGBT-based 10kW prototype.
Digital Control of Secondary Active Clamp Phase-Shifted Full-Bridge Converters
Che, Yanbo,Ma, Yage,Ge, Shaoyun,Zhu, Dong The Korean Institute of Power Electronics 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.3
A DSP-based self-adaptive proportional-integral (PI) controller to control a DC-DC converter is proposed in this paper. The full-bridge topology is adopted here to obtain higher power output capability and higher conversion efficiency. The converter adopts the zero-voltage-switching (ZVS) technique to reduce the conduction losses. A parallel secondary active clamp circuit is added to deal with the voltage overshoot and ringing effect on the transformer's secondary side. A self-adaptive PI controller is proposed to replace the traditional PI controller. Moreover, the designed converter adopts the constant-current and constant-voltage (CC-CV) output control strategy. The secondary active clamp mechanism is discussed in detail. The effectiveness of the proposed converter was experimentally verified by an IGBT-based 10kW prototype.
Fair Resource Allocation with QoS Guarantee in Secure Multiuser TDMA Networks
Bai, Zhiquan,Wang, Tongtong,Ma, Piming,Ma, Yanbo,Kwak, Kyungsup WILEY INTERSCIENCE 2018 WIRELESS COMMUNICATIONS AND MOBILE COMPUTING Vol.2018 No.-
<P>We investigate a secure multiuser time division multiple access (TDMA) system with statistical delay quality of service (QoS) guarantee in terms of secure effective capacity. An optimal resource allocation policy is proposed to minimize the <TEX>$ \beta $</TEX> -fair cost function of the average user power under the individual QoS constraint, which also balances the energy efficiency and fairness among the users. First, convex optimization problems associated with the resource allocation policy are formulated. Then, a subgradient iteration algorithm based on the Lagrangian duality theory and the dual decomposition theory is employed to approach the global optimal solutions. Furthermore, considering the practical channel conditions, we develop a stochastic subgradient iteration algorithm which is capable of dynamically learning the intended wireless channels and acquiring the global optimal solution. It is shown that the proposed optimal resource allocation policy depends on the delay QoS requirement and the channel conditions. The optimal policy can save more power and achieve the balance of the energy efficiency and the fairness compared with the other resource allocation policies.</P>
Hui Wang,Yuanhao Guan,Shaozheng Hu,Yanbo Pei,Wentao Ma,Zhiping Fan 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.2
Here, band gap-tunable oxygen-doped graphitic carbon nitride (g-C3N4) with outstanding “two-channel” photocatalytic H2O2 production ability was prepared via hydrothermal treatment assisted by dissolution–precipitation process. XRD, N2 adsorption, UV–Vis, Fourier-transform infrared spectra, SEM, electrochemical impedance spectra, XPS and photoluminescence were used to characterize the obtained catalysts. The photocatalytic H2O2 production ability of as-prepared catalyst was investigated. The results show that oxygen doping not only changes the morphology of catalyst, decreases the band gap energy and promotes the separation efficiency of photogenerated electrons and holes, but also tunes the CB and VB potentials. As-prepared oxygen-doped g-C3N4 displays a H2O2 concentration of 3.8 mmol L -1, more than 7.6 times higher than that of neat g-C3N4. Because of the shift of CB and VB potentials, not only the CB electrons of oxygen-doped g-C3N4 reduce O2 to form H2O2, but also the VB holes can oxidize OH- to form OH, which subsequently react with each other to form H2O2. Such “two-channel pathway” causes the remarkably promoted H2O2 production ability.
Jinxin Jiang,Wei-Haur Lam,Yonggang Cui,Tianming Zhang,Chong Sun,Jianhua Guo,Yanbo Ma,Shuguang Wang,Gerard Hamill 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.3
The current research proposed the theoretical model for ship twin-propeller jet based on the axial momentum theory and Gaussian normal distribution. The twin-propeller jet model is compared to the more matured single propeller jet model with good agreement. Computational Fluid Dynamics (CFD) method is used to acquire the velocity distribution within the twin-propeller jet for understanding of flow characteristics and validation purposes. Efflux velocity is the maximum velocity within the entire jet with strong influences by the geometrical profiles of the blades. Twin-propeller jet model showed four-peaked profile at the initial plane downstream to the propeller compared to the two-peaked profile from a single-propeller. The four-peaked profile merges to be twopeaked velocity profile and then one-peaked profile due to the fluid mixing. Entrainment occurs between the ambient still water outside and the rotating flow within jet due to the high velocity gradient. The research proposes a twin-propeller jet theory with a serial of equations enabling the predictions of velocity magnitude within the jet.