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114 results on '"Sun, Pengju"'

3. Automatic Digital Optimization Design of Synchronous Rectification Buck Converter

Author

Dong, Shufan, Luo, Quanming, Wei, Mengjia, Lai, Guolin, Chen, Jian, Sun, Pengju, and Du, Xiong

Abstract

The loss and volume of the synchronous buck converter are influenced by various circuit parameters such as switching frequency, inductor, and dead time. However, their impact on the loss and volume has not been comprehensively analyzed and evaluated. To investigate and assess the loss and volume of synchronous buck converter over a wide load range, an automatic digital optimization design method is proposed in this article. First, the process established a complete circuit analytical model based on various operating conditions. Then, with the developed analytical model, the methodology is developed to comprehensively evaluate the loss and volume of the converter and investigate the impacts of the above-mentioned factors. Experimental results demonstrate that the proposed method can accurately predict the effects of switching frequency and inductor on the converter's efficiency and power density. Moreover, the method is effective in optimizing dead time. The proposed analysis and method provide guidance and a foundation for the parameter optimization and design of the synchronous buck converter.

Published
2024
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4. A Full-Iteration Optimal Design Methodology of CLLC Converter With Minimized RMS Current

Author

Luo, Ting, Luo, Quanming, Li, Jia, Yuan, Xueyi, Yan, Yipeng, Yin, Miaomiao, Sun, Pengju, and Du, Xiong

Abstract

With the wide application of the CLLC converters in bidirectional electric vehicle chargers, it becomes more important to improve their performance through proper parameter design. Compared with the frequency domain model, the time-domain model can significantly improve the accuracy of converter design. However, the currently generalized operation mode analysis method requires complicated operating mode judgment and solving systems of transcendental equations, which limits its practicality. To address this issue, a discrete event-driven piecewise analytic model (DEPAM) of CLLC converter is proposed in this article. DEPAM obtains the transient and steady-state waveforms without the need for operating mode judgment and solving transcendental equations. Relying on DEPAM, a design methodology of the CLLC converter is introduced in this article, which applies the lookup table method to the normalized parameters and achieves a complete traversal of all possible parameter combinations of the CLLC converter. This traversal considers gain range, soft-switching, capacitor voltage stress, and rms current simultaneously. Finally, the design methodology is demonstrated through a 1 kW prototype with 98.8% peak efficiency.

Published
2024
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5. Online Monitoring Bond Wires Fault of SiC MOSFETs With Kelvin Package Based on Turn-on Source Voltage Ringing

Author

Xie, Minghang, Sun, Pengju, Ouyang, Wenyuan, Luo, Quanming, and Du, Xiong

Abstract

Bond wire fault is one of the most prominent degradation types for silicon carbide (SiC) mosfets, which could be detected and monitored through appropriate precursors. In this article, an online bond wire fault monitoring method for SiC mosfets with Kelvin package is proposed. It is based on the fact that the bond wires parasitic inductances are affected by bond wire fault over time. The variations of parasitic inductances can be converted into the variations of the voltage ringing between the Kelvin source and power source (vKS-S) during the turn-on event. To eliminate the affecting factors, the voltage ringing of the circuit parasitic inductance (vCIR) is introduced, and the division of the peak values of the two voltages ringing is used as the new bond wire fault precursor. The study results indicate that the proposed precursor has high sensitivity and high resolution to monitor each bond wire fault. Besides, the monitoring results are not affected by factors such as junction temperature, load current, and bus voltage. Therefore, the proposed fault monitoring method can be implemented online without knowing the factor information. The confirmatory experiment is carried out to verify the correctness of the proposed method.

Published
2024
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15. A Multitime-Scale Analytical Model of ZVS Buck Converter

Author

Wei, Mengjia, Luo, Quanming, Chen, Jian, Zhang, Xinyue, Xiong, Lujing, Sun, Pengju, and Du, Xiong

Abstract

This article presents a modeling method to build a complete and accurate multitime-scale analytical model for low-voltage eGaN HEMTs-based zero-voltage switching buck converter with consideration of parasitic inductors, nonlinear junction capacitors, and nonlinear transconductance. The switching steady-state modes and switching transient modes are discussed in detail based on their corresponding equivalent circuits. The state equations of each mode are solved by MATLAB software to obtain the key operating waveforms throughout one switching cycle. Moreover, the established switching steady-state model and switching transient model are numerically merged together through continuous state variables, and then the multitime-scale model for stable operation is formed based on the iterative method. The waveforms and switching energy losses predicted by the model within one switching cycle are compared with the experimental results, respectively, to verify the accuracy of the model. In the end, the dead time is optimized based on the proposed model, and the optimization result is verified to be effective in reducing the switching energy loss through the experiment.

Published
2023
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17. Quantile Regression Learning with Coefficient Dependent lq-Regularizer

Author

Sun Pengju, Li Meng, and Sun Hongwei

Subjects
Engineering (General). Civil engineering (General), TA1-2040
Abstract

In this paper, We focus on conditional quantile regression learning algorithms based on the pinball loss and lq-regularizer with 1≤q≤2. Our main goal is to study the consistency of this kind of regularized quantile regression learning. With concentration inequality and operator decomposition techniques, we obtained satisfied error bounds and convergence rates.

Published
2018
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24. Analysis and design of the DCM operation boost PFC converter with magnetic control

Author

Jie Wang, Yuqi Wei, Sun Pengju, and Quanming Luo

Subjects
Computer science, 020209 energy, 020208 electrical & electronic engineering, Automatic frequency control, PID controller, 02 engineering and technology, Power factor, Inductor, Variable (computer science), Control theory, Duty cycle, 0202 electrical engineering, electronic engineering, information engineering, Electrical and Electronic Engineering, Voltage, Machine control
Abstract

In this study, a novel control scheme for the discontinuous conduction mode (DCM) operation boost power factor correction (PFC) converter is proposed. Instead of adopting constant duty cycle (CDC) control, variable duty cycle control or frequency control, the magnetic control or variable inductor control is adopted to regulate the output voltage, so CDC and switching frequency can be implemented for the switch. The operation principles of the proposed control scheme are discussed in details, and the analysis of the input current, power factor, boundary condition and design considerations are presented. In addition, the modelling of the variable inductor and the DCM operation boost PFC converter with variable inductor are derived in detail, by linearising the non-linear components, the model of the DCM operation boost PFC converter with the proposed control scheme can be obtained, and the design procedures of the PI controller are presented. Finally, a 70 W experimental prototype is built to verify the theoretical analysis and the effectiveness of the proposed control scheme.

Published
2019

45. Analysis and design of the DCM operation boost PFC converter with magnetic control.

Author

Yuqi Wei, Quanming Luo, Jie Wang, and Sun Pengju

Subjects
CORRECTION factors, AC DC transformers, DESIGN
Abstract

In this study, a novel control scheme for the discontinuous conduction mode (DCM) operation boost power factor correction (PFC) converter is proposed. Instead of adopting constant duty cycle (CDC) control, variable duty cycle control or frequency control, the magnetic control or variable inductor control is adopted to regulate the output voltage, so CDC and switching frequency can be implemented for the switch. The operation principles of the proposed control scheme are discussed in details, and the analysis of the input current, power factor, boundary condition and design considerations are presented. In addition, the modelling of the variable inductor and the DCM operation boost PFC converter with variable inductor are derived in detail, by linearising the non-linear components, the model of the DCM operation boost PFC converter with the proposed control scheme can be obtained, and the design procedures of the PI controller are presented. Finally, a 70 W experimental prototype is built to verify the theoretical analysis and the effectiveness of the proposed control scheme. [ABSTRACT FROM AUTHOR]

Published
2019
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