High Efficiency Current-Fed Dual Active Bridge DC–DC Converter with ZVS Achievement Throughout Full Range of Load Using Optimized Switching Patterns

Author(s):  
Deshang Sha ◽  
Guo Xu
Author(s):  
Qun Chen ◽  
Zong-Xiao Yang ◽  
Zhumu Fu

Purpose The problem of parameter identification for biaxial piezoelectric stages is still a challenging task because of the existing hysteresis, dynamics and cross-axis coupling. This study aims to find an accurate and systematic approach to tackle this problem. Design/methodology/approach First, a dual-input and dual-output (DIDO) model with Duhem-type hysteresis is proposed to depict the dynamic behavior of the biaxial piezoelectric stage. Then, a systematic identification approach based on a modified differential evolution (DE) algorithm is proposed to identify the unknown parameters of the Duhem-type DIDO model for a biaxial piezostage. The randomness and parallelism of the modified DE algorithm guarantee its high efficiency. Findings The experimental results show that the characteristics of the biaxial piezoelectric stage can be identified with adequate accuracy based on the input–output data, and the peak-valley errors account for 2.8% of the full range in the X direction and 1.5% in the Y direction. The attained results validated the correctness and effectiveness of the presented identification method. Originality/value The classical DE algorithm has many adjustment parameters, which increases the inconvenience and difficulty of using in practice. The parameter identification of Duhem-type DIDO piezoelectric model is rarely studied in detail and its successful application based on DE algorithm on a biaxial piezostage is hitherto unexplored. To close this gap, this work proposed a modified DE-based systematic identification approach. It not only can identify this complicated model with more parameters, but also has little tuning parameters and thus is easy to use.


Electronics ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 363 ◽  
Author(s):  
Alfredo Medina-Garcia ◽  
Manfred Schlenk ◽  
Diego Morales ◽  
Noel Rodriguez

In this article, an innovative power adaptor based on the asymmetrical pulse width modulation (PWM) flyback topology will be presented. Its benefits compared to other state-of-the-art topologies, such as the active clamp flyback, are analyzed in detail. It will also describe the control methods to achieve high efficiency and power density using zero-voltage switching (ZVS) and zero-current switching (ZCS) techniques over the full range of the input voltage and the output load, providing comprehensive guidelines for the practical design. Finally, we demonstrate the convenience of the proposed design methods with a 65 W adaptor prototype achieving a peak efficiency of close to 95% and a minimum efficiency of 93.4% at full load over the range of the input voltage, as well as a world-class power density of 22 W/inch3 cased.


1995 ◽  
Vol 31 (1) ◽  
pp. 141-148 ◽  
Author(s):  
Luigi Malesani ◽  
Paolo Tenti ◽  
Paolo Tomasin ◽  
Vanni Toigo

2006 ◽  
Vol 3 (3) ◽  
pp. 1125-1144 ◽  
Author(s):  
J. C. Huang ◽  
S. J. Kao

Abstract. The often-used success rate (SR) in measuring cell-based landslide model efficiency is based on the ratio of successfully predicted unstable cells over total actual landslide sites without considering the performance in predicting stable cells. We proposed a modified SR (MSR), in which we include the performance of stable cell prediction. The goal and virtue of MSR is to avoid over-prediction while upholding stable sensitivity throughout all simulated cases. Landslide susceptibility maps (a total of 3969 cases) with full range of performance (from worse to perfect) in stable and unstable cell predictions are created and used to probe how estimators respond to model results in calculating efficiency. The kappa method used for satellite image analysis is drawn for comparison. Results indicate that kappa is too stern for landslide modeling giving very low efficiency values in 90% simulated cases. The old SR tends to give high model efficiency under certain conditions yet with significant over-prediction. To examine the capability of MSR and the differences between SR and MSR as performance indicator, we applied the SHALSTAB model onto a mountainous watershed in Taiwan. Despite the fact the best model result deduced by SR projects 120 hits over 131 actual landslide sites, this high efficiency is only obtained when unstable cells cover an incredibly high percentage (75%) of the entire watershed. By contrast, the best simulation indicated by MSR projects 83 hits over 131 actual landslide sites while unstable cells only cover 16% of the studied watershed.


Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6786
Author(s):  
Yuto Takayama ◽  
Hiroaki Yamada

In this study, we deal with a dual active bridge (DAB) converter-based battery charger in a standalone wind power generation system (WPGS) with a small-scale wind turbine. However, the power conversion efficiency under the low power output in the discharging mode is low. In this paper, we propose variable DC-link voltage control in a standalone WPGS with a DAB converter under a light load. The proposed control can compensate for the shortage of generated power and suppress the peak value of the transformer current. Simulation results demonstrate that the proposed control can decrease the peak value of the transformer current and improve the power conversion efficiency of the DAB converter. An experimental setup was constructed to confirm the basic operation of the variable DC-link voltage control. In addition, a reference DC-link voltage switchover control is proposed to enable a high-efficiency drive under all load ranges. From simulation results, the power loss can be reduced by the switchover control of the reference DC-link voltage.


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