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Multi-channel inductive power transfer system based on ISOP topology
Qijun Deng,Lixian Wang,Peng Luo,Dariusz Czarkowski,Wenshan Hu 전력전자학회 2024 JOURNAL OF POWER ELECTRONICS Vol.24 No.3
With the expansion of mid-voltage DC distribution, inductive power transfer (IPT) systems supplied directly by DC distribution with a high input voltage become a possibility. A high input voltage leads to an enhanced power transfer level and low losses with the DC bus under a certain power transmission. However, the ultra-high input voltage of single-channel IPT is impossible because of the limits on the voltage/current ratings of converter components. Thus, a multi-channel IPT system based on an input-series output-parallel (ISOP) topology is proposed. Parameter differences among various channels result in an unbalanced input voltage for series inverters, which affects the system's operation stability and life. A leader–follower control strategy is proposed to implement input voltage sharing and output load voltage tracking for the proposed ISOP-based IPT system. One of the inverters serves as the lead control unit to keep the output voltage constant, while the remaining inverters function as followers that trace the input DC voltage of the main channel to implement voltage sharing among the inverters. A three-channel ISOP-based IPT prototype is constructed to verify the eff ectiveness of the control strategy. Experimental results show that the input voltage sharing and constant output voltage are both achieved under the designed controller.
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Mengfei Qu,Yu Bai,Qijun Hu,Leping He,Enxi Qiu,Xusheng Wan 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.11
The measurement of the saturated internal friction angle of landslide sliding zone soils during the geological investigation could assist in engineering design, as it is a crucial parameter for landslide control. This research developed a comprehensive method to predict the saturated internal friction angle based on the support vector machine (SVM), after investigating the relationship between the saturated internal friction angle and the factors that affect the saturated internal friction angle. The procedure mainly consists of exploratory data analysis, influencing factors analysis, and prediction model set-up. Among the 18 factors, the evolution stage, gravel content, plasticity index, and dry unit weight were the most relevant factors predicting the saturated internal friction angle. The proposed method was illustrated and verified by a model accuracy test with the mean absolute error of the radial basis functions (RBF) kernel function was 0.90°, and the mean relative error was 8.77%. Therefore, this method could provide a reliable saturated internal friction angle in assisting engineers during landslide control.
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Cheng Chen,Hong Zhou,Qijun Deng,Wenshan Hu,Yanjuan Yu,Xiaoqing Lu,Jingang Lai 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.5
Zero-Voltage-Switching (ZVS) operation for a Wireless Power Transfer (WPT) system can be achieved by designing a ZVS controller. However, the performance of the controller in some industrial applications needs to be designed tightly. This paper introduces a ZVS controller design method for WPT systems. The parameters of the controller are designed according to the desired performance based on the closed loop dominant pole placement method. To describe the dynamic characteristics of the system ZVS angle, a nonlinear dynamic model is deduced and linearized using the small signal linearization method. By analyzing the zero-pole distribution, a low-order equivalent model that facilitates the controller design is obtained. The parameters of the controller are designed by calculating the time constant of the closed-loop dominant poles. A prototype of a WPT system with the designed controller and a five-stage multistage series variable capacitor (MSVC) is built and tested to verify the performance of the controller. The recorded response curves and waveforms show that the designed controller can maintain the ZVS angle at the reference angle with satisfactory control performance.
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Zhu Jintuo,Jiang Qijun,Ye Yuxuan,He Xinjian,Shao Jiang,Li Xinyu,Zhao Xijie,Xu Huan,Hu Qi 한국산업안전보건공단 산업안전보건연구원 2023 Safety and health at work Vol.14 No.4
Background: During hot environment work tasks with whole-body enclosed anti-bioaerosol suit, the combined effect of heavy sweating and exhaled hot humid air may cause the N95 medical respirator to saturate with water/sweat (i.e., water-blocking). Methods: 32 young male subjects with different body mass indexes (BMI) in whole-body protection (N95 medical respirator + one-piece protective suit + head covering + protective face screen + gloves + shoe covers) were asked to simulate waste collecting from each isolated room in a seven-story building at 27-28°C, and the weight, inhalation resistance (Rf), and aerosol penetration of the respirator before worn and after water-blocking were analyzed. Results: All subjects reported water-blocking asphyxia of the N95 respirators within 36-67 min of the task. When water-blocking occurred, the Rf and 10-200 nm total aerosol penetration (Pt) of the respirators reached up to 1270-1810 Pa and 17.3-23.3%, respectively, which were 10 and 8 times of that before wearing. The most penetration particle size of the respirators increased from 49-65 nm before worn to 115-154 nm under water-blocking condition, and the corresponding maximum size-dependent aerosol penetration increased from 2.5-3.5% to 20-27%. With the increase of BMI, the water-blocking occurrence time firstly increased then reduced, while the Rf, Pt, and absorbed water all increased significantly. Conclusions: This study reveals respirator water-blocking and its serious negative impacts on respiratory protection. When performing moderate-to-high-load tasks with whole-body protection in a hot environment, it is recommended that respirator be replaced with a new one at least every hour to avoid water-blocking asphyxia.
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Chen, Cheng,Zhou, Hong,Deng, Qijun,Hu, Wenshan,Yu, Yanjuan,Lu, Xiaoqing,Lai, Jingang The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.5
Zero-Voltage-Switching (ZVS) operation for a Wireless Power Transfer (WPT) system can be achieved by designing a ZVS controller. However, the performance of the controller in some industrial applications needs to be designed tightly. This paper introduces a ZVS controller design method for WPT systems. The parameters of the controller are designed according to the desired performance based on the closed loop dominant pole placement method. To describe the dynamic characteristics of the system ZVS angle, a nonlinear dynamic model is deduced and linearized using the small signal linearization method. By analyzing the zero-pole distribution, a low-order equivalent model that facilitates the controller design is obtained. The parameters of the controller are designed by calculating the time constant of the closed-loop dominant poles. A prototype of a WPT system with the designed controller and a five-stage multistage series variable capacitor (MSVC) is built and tested to verify the performance of the controller. The recorded response curves and waveforms show that the designed controller can maintain the ZVS angle at the reference angle with satisfactory control performance.
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