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Liu Jinfeng,Xu Zhaoyun,Zhang Zhenglei,Iu Herbert Ho-Ching 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.1
The low voltage, high current rectifer module is the core of the integrated DC output system based on synchronous generators. In addition, modular control improves the fexibility of the system control and fault-tolerant operation ability. Due to the dispersion of the on-state voltage drop of switching devices, it is possible to cause a circulating current fault between the parallel modules, which leads to the reduction of the current sharing characteristics and stability of the system. Therefore, it is signifcant to address the shortcomings of traditional current sharing methods such as poor anti-disturbance performance. This paper proposes a current sharing scheme that improves the control accuracy by fltering the sampled current on the basis of autonomous sharing of maximum current. Furthermore, a model of the integrated generator rectifer system was established by Simulink to realize the simulation of the modular SVPWM (Space-Vector Pulse-Width Modulation) rectifer control based on MA (Moving Average) fltering algorithm. At last, an experimental platform was built in this paper in order to verify the feasibility of the theory. In this experimental platform, the controller completes digital current sharing control and fnally realizes the synchronous generator module paralleling system 5 V/1000A DC output. The simulation and experiment demonstrate that the integrated output current sharing control method in this paper has higher control precision and better anti-interference performance.
Jinfeng Liu,Xudong Wang,Rui Gong 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.12
In order to solve the problem about the brush and slip ring in drive motor of renewable energy vehicle, high frequency power magnetic field produced by a novel separable magnetic pot transformer could achieve contactless excitation energy transfer. For contactless energy transfer (CET) system, its research about energy and efficiency quality still remains a low level because application and research of CET are not integrated, especially how to improve transmission power and efficiency is still not enough. First of all in this paper, the topology of magnetic pot transformer is built to design resonant compensation circuit. Secondly, mutual inductance parameter is proposed by optimum efficiency analysis through calculation. Thirdly, circuit simulation model of Matlab and 3D simulation model of Ansoft Maxwell which can complete finite element transient analysis are built to verify the accuracy of optimum efficiency analysis. Lastly, the experiment platform about CET in synchronous generator prototype is performed. Although the output power had little increase, experiment and Matlab, Ansoft 3D simulation research proved that system efficiency had a quite increase based on optimum efficiency analysis.
Jinfeng Liu,Kun Li,Ningzhi Jin,Herbert Ho-Ching IU 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.5
In this paper, a detuning factor (DeFac) method is proposed to design the key parameters for optimizing the transfer power and efficiency of an Inductively Coupled Power Transfer (ICPT) system with primary-secondary side compensation. Depending on the robustness of the system, the DeFac method can guarantee the stability of the transfer power and efficiency of an ICPT system within a certain range of resistive-capacitive or resistive-inductive loads. A MATLAB-Simulink model of a ICPT system was built to assess the system’s main evaluation criteria, namely its maximum power ratio (PR) and efficiency, in terms of different approaches. In addition, a magnetic field simulation model was built using Ansoft to specify the leakage flux and current density. Simulation results show that both the maximum PR and efficiency of the ICPT system can reach almost 70% despite the severe detuning imposed by the DeFac method. The system also exhibited low levels of leakage flux and a high current density. Experimental results confirmed the validity and feasibility of an ICPT system using DeFac-designed parameters.
Liu, Jinfeng,Li, Kun,Jin, Ningzhi,Iu, Herbert Ho-Ching The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.5
In this paper, a detuning factor (DeFac) method is proposed to design the key parameters for optimizing the transfer power and efficiency of an Inductively Coupled Power Transfer (ICPT) system with primary-secondary side compensation. Depending on the robustness of the system, the DeFac method can guarantee the stability of the transfer power and efficiency of an ICPT system within a certain range of resistive-capacitive or resistive-inductive loads. A MATLAB-Simulink model of a ICPT system was built to assess the system's main evaluation criteria, namely its maximum power ratio (PR) and efficiency, in terms of different approaches. In addition, a magnetic field simulation model was built using Ansoft to specify the leakage flux and current density. Simulation results show that both the maximum PR and efficiency of the ICPT system can reach almost 70% despite the severe detuning imposed by the DeFac method. The system also exhibited low levels of leakage flux and a high current density. Experimental results confirmed the validity and feasibility of an ICPT system using DeFac-designed parameters.
Jinfeng Liu,Yu Zhang,Xudong Wang,Herbert Ho-Ching IU 대한전기학회 2017 Journal of Electrical Engineering & Technology Vol.12 No.4
This paper presents a synchronous generator with a distributed system of multiple parallel three-phase power cells. This generator can immediately output high DC. Each power cell comprises three-phase windings and a three-phase synchronous rectification bridge with a deadbeat control of load power feedforward, which can improve the characteristics of dynamic response and reflect the load variance in real time. Furthermore, each power cell works well independently and modularly using the method of automatic maximum current sharing. The simulation and experimental results for the distributed controller of multiple power cells demonstrate that the deadbeat control method can respond quickly and optimize the quality of the energy. Meanwhile, automatic maximum current sharing can realize the validity of current sharing among power cells.
Liu, Jinfeng,Zhang, Yu,Wang, Xudong,IU, Herbert Ho-Ching The Korean Institute of Electrical Engineers 2017 Journal of Electrical Engineering & Technology Vol.8 No.1
This paper presents a synchronous generator with a distributed system of multiple parallel three-phase power cells. This generator can immediately output high DC. Each power cell comprises three-phase windings and a three-phase synchronous rectification bridge with a deadbeat control of load power feedforward, which can improve the characteristics of dynamic response and reflect the load variance in real time. Furthermore, each power cell works well independently and modularly using the method of automatic maximum current sharing. The simulation and experimental results for the distributed controller of multiple power cells demonstrate that the deadbeat control method can respond quickly and optimize the quality of the energy. Meanwhile, automatic maximum current sharing can realize the validity of current sharing among power cells.
Depth tracking of occluded ships based on SIFT feature matching
Yadong Liu,Yuesheng Liu,Ziyang Zhong,Yang Chen,Jinfeng Xia,Yunjie Chen 한국인터넷정보학회 2023 KSII Transactions on Internet and Information Syst Vol.17 No.4
Multi-target tracking based on the detector is a very hot and important research topic in target tracking. It mainly includes two closely related processes, namely target detection and target tracking. Where target detection is responsible for detecting the exact position of the target, while target tracking monitors the temporal and spatial changes of the target. With the improvement of the detector, the tracking performance has reached a new level. The problem that always exists in the research of target tracking is the problem that occurs again after the target is occluded during tracking. Based on this question, this paper proposes a DeepSORT model based on SIFT features to improve ship tracking. Unlike previous feature extraction networks, SIFT algorithm does not require the characteristics of pre-training learning objectives and can be used in ship tracking quickly. At the same time, we improve and test the matching method of our model to find a balance between tracking accuracy and tracking speed. Experiments show that the model can get more ideal results.
Jinfeng Zhang,Guanyi Chen,Yanning Ma,Miao Xu,Songyan Qin,Xiaoliang Liu,Haijun Feng,Lian Hou 대한환경공학회 2022 Environmental Engineering Research Vol.27 No.1
A new technique for treating pickling wastewater discharged from the steel industry using membrane filters was developed and membrane fouling was characterized in a full scale membrane filter. The morphological and chemical properties were examined through scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and inductively coupled plasma optical emission spectroscopy (ICP-OES) etc. The results showed that inorganic elements such as phosphates, chlorides, and sulfates were severely blocked in membrane surfaces and pores. The porosity, permeability, hydrophilic contact angle, and surface charge capacity of fouled membranes were all lower than those of new membranes, while the optimal neutralization reaction pH region for fouled membranes shifted and narrowed. Charge neutralization is a critical reason to membrane fouling. By increasing the Zeta potential of the pickling wastewater, the membrane fouling could be controlled. This method is proven to effectively improve the separation property of precipitates after pickling wastewater was neutralized. Moreover, Neutralization helped to reduce the unit number of treatment processes. This investigation could assist in obtaining a better understanding of the fouling properties and behavior in the full-scale membrane filters in the pickling wastewater treatment.