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Implementation of a Stand-alone Photovoltaic Pumping System with Maximum Power Point Tracking
Zhao Zhengming,Chen Kunlun,Yuan Liqiang 전력전자학회 2001 ICPE(ISPE)논문집 Vol.2001 No.10
Photovoltaic (PV) pumping systems with maximum power point tracking (MPPT) technique aims at obtaining the highest possible power to the pump under various insolation and temperature, thus overcomes the mismatch between the photovoltaic panel and the pumping load. A simple method of tracking the maximum power points and forcing the system to operate close to these points is presented in this paper. The MC68HC908GP32 micro control unit (MCU) is employed to implement the proposed MPPT controller. Experimental results will also show the performances of the photovoltaic pumping system with the MPPT technique.<br/>
Gaohui Feng,Liqiang Yuan,Zhengming Zhao,Junjie Ge,Xiuxi Ye,Ting Lu 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.2
This paper focuses on an improvement in the transient performance of Boost converters when the load changes abruptly. This is achieved on the basis of the nature trajectory in Boost converters. Three key aspects of the transient performance are analyzed including the storage energy change law in the inductors and capacitors of converters during the transient process, the ideal minimum voltage deviation in the transient process, and the minimum voltage deviation control trajectory. The changing relationship curve between the voltage deviation and the recovery time is depicted through analysis and simulations when the load suddenly increases. In addition, the relationship curve between the current fluctuation and the recovery time is obtained when the load suddenly decreases. Considering the aspects of an increasing and decreasing load, this paper proposes the transient performance synthetic optimized trajectory and control laws. Through simulation and experimental results, the transient performances are compared with the other typical three control methods, and the ability of proposed synthetic trajectory and control law to achieve optimal transient performance is verified.
Tradeoff between the Output Voltage Deviation and Recovery Time of Boost Converters
Junjie Ge,Liqiang Yuan,Zhengming Zhao,Ting Lu,Fanbo He,Gaohui Feng 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.2
The time-optimal control for boost converters can achieve the minimum recovery time. However, their output voltage deviation is quite large. Since the minimum output voltage deviation and minimum recovery time cannot be obtained at the same time, a novel energy control is proposed to achieve a superior tradeoff between them in this paper. The peak value of the inductor current can be decreased as well. Its control parameter is easy to choose. When compared with the conventional control methods, the proposed control shows a better dynamic performance. Experimental results, which are in agreement with the theoretical analysis, are provided to verify the proposed control method.
Hongwen He,Liqiang Cao,Lixi Wan,Haiyan Zhao,Guangchen Xu,Fu Guo 대한금속·재료학회 2012 ELECTRONIC MATERIALS LETTERS Vol.8 No.4
The electromigration test was conducted in Cu/Sn-58Bi/Cu solder joint with high current density of 104 A/cm2. Results showed that a large number of whiskers with natural weed appearance were observed at the cathode side in such a short current stressing time. Furthermore, some secondary whiskers were attached to the primary whiskers, which has never been reported before. We presumed the vapor-solid (VS) mechanism to explain the oxide whiskers growth, which was quite different from the traditional theory that the compressive stress took on the driving force. In conclusion, due to the over-Joule heating effect, the metal oxide whiskers were synthesized in bulk quantities by thermal evaporation of Sn oxide and Bi oxide.
Tradeoff between the Output Voltage Deviation and Recovery Time of Boost Converters
Ge, Junjie,Yuan, Liqiang,Zhao, Zhengming,Lu, Ting,He, Fanbo,Feng, Gaohui The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.2
The time-optimal control for boost converters can achieve the minimum recovery time. However, their output voltage deviation is quite large. Since the minimum output voltage deviation and minimum recovery time cannot be obtained at the same time, a novel energy control is proposed to achieve a superior tradeoff between them in this paper. The peak value of the inductor current can be decreased as well. Its control parameter is easy to choose. When compared with the conventional control methods, the proposed control shows a better dynamic performance. Experimental results, which are in agreement with the theoretical analysis, are provided to verify the proposed control method.
Feng, Gaohui,Yuan, Liqiang,Zhao, Zhengming,Ge, Junjie,Ye, Xiuxi,Lu, Ting The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.2
This paper focuses on an improvement in the transient performance of Boost converters when the load changes abruptly. This is achieved on the basis of the nature trajectory in Boost converters. Three key aspects of the transient performance are analyzed including the storage energy change law in the inductors and capacitors of converters during the transient process, the ideal minimum voltage deviation in the transient process, and the minimum voltage deviation control trajectory. The changing relationship curve between the voltage deviation and the recovery time is depicted through analysis and simulations when the load suddenly increases. In addition, the relationship curve between the current fluctuation and the recovery time is obtained when the load suddenly decreases. Considering the aspects of an increasing and decreasing load, this paper proposes the transient performance synthetic optimized trajectory and control laws. Through simulation and experimental results, the transient performances are compared with the other typical three control methods, and the ability of proposed synthetic trajectory and control law to achieve optimal transient performance is verified.
Xiaoxing Yang,Jiachun Zhou,Liqiang Fan,Zhen Qin,Qiming Chen,Liming Zhao 한국식품과학회 2018 Food Science and Biotechnology Vol.27 No.6
Fermented vegetable–fruit beverages are a popular fermented food, with many potential health benefits. In this study, two commercial Lactobacillus plantarum strains were selected to ferment a beverage containing apples, pears, and carrots. The metabolites and antioxidant activities were examined during the fermentation process. Results showed that lactic acid and acetic acid accumulated gradually, whereas malic acid decreased. Glucose and fructose increased from 0.48 and 14.8 g/L to 7.7 and 20.8 g/L, respectively, while sucrose decreased slightly. Ascorbic acid also increased continuously during the fermentation to 90.74 mg/100 mL. DPPH and ABTS radical scavenging activity and FRAP reached their maximum value after 4–8 days. The accumulation of TPC, TFC, and SOD reached their maximum value on the 8th day of fermentation. Our study revealed that the L. plantarum-fermented vegetable–fruit beverage showed significant antioxidant activity, which is helpful in evaluating the fermentation end-point and developing a high-quality fermented beverage.
Competitive Resource Sharing Based on Game Theory in Cooperative Relay Networks
Guopeng Zhang,Li Cong,Liqiang Zhao,Hailin Zhang,Kun Yang 한국전자통신연구원 2009 ETRI Journal Vol.31 No.1
This letter considers the problem of resource sharing among a relay and multiple user nodes in cooperative transmission networks. We formulate this problem as a sellers’ market competition and use a noncooperative game to jointly consider the benefits of the relay and the users. We also develop a distributed algorithm to search the Nash equilibrium, the solution of the game. The convergence of the proposed algorithm is analyzed. Simulation results demonstrate that the proposed game can stimulate cooperative diversity among the selfish user nodes and coordinate resource allocation among the user nodes effectively.
Shengxiang Zhang,Yuanyuan Shi,Chunmiao Shan,Liqiang Zhao,Kelong Ma,Luqi Huang,Jiawen Wu 한국식물학회 2020 Journal of Plant Biology Vol.63 No.3
Polygonatum odoratum (Mill.) Druce (P. odoratum) is a traditional Chinese herb. The isofavonoids of P. odoratum are important medicinal bioactive compounds for the treatment of hypoimmunity, rheumatic heart disease, cardiovascular diseases, and diabetes. This study used RNA sequencing to identify potential genes regulating isofavonoid biosynthesis in P. odoratum. To do this, we generated an overview of metabolic and secondary metabolic pathways, using MAPMAN, and identifed 96 genes encoding seven key enzymes involved in isofavonoid biosynthesis through their KEGG annotation. Alignment of phenylalanine ammonia-lyase or chalcone synthase amino acid sequences revealed well-conserved sequences, spatial structures, and active sites. We also verifed the expression of key genes encoding phenylalanine ammonia-lyase and chalcone synthase by quantitative real-time PCR (qRT-PCR). This analysis of the isofavonoid biosynthesis pathway and its crucial enzymes in P. odoratum lays the foundation for uncovering the regulatory mechanism of isofavonoid biosynthesis.
SOI radiation‑hardened 300 V half‑bridge date driver IC design with high dv/dt noise immunity
Yuexin Gao,Xiaowu Cai,Zhengsheng Han,Yun Tang,Liqiang Ding,Ruirui Xia,Mali Gao,Fazhan Zhao 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.5
Noise immunity is a critical index of high-voltage half-bridge gate driver integrated circuits (IC). Various noise cancelation technologies have been proposed to improve dv/dt noise immunity with sacrifices in terms of area and propagation delay time. Besides, when it is applied to an inductive load, the half-bridge driver is vulnerable to negative surges at the VS terminal, which is the offset ground of the high-side channel. A 300 V half-bridge gate driver IC with noise rejection module is designed in this paper. The noise immunity can be improved to 87.5 V/ns. The VS negative swing region can be extended to − 5.1 V. In addition, the proposed driver IC can work normally at a working frequency of 500 kHz and the delay matching time between the high-side and the low-side is less than 4 ns. The propagation delay time of the high-side channel is measured at 71.6 ns. Furthermore, gamma ray irradiation experimental results show that the proposed structure presents a good radiation tolerance of 100 krad (Si). The presented half-bridge gate driver IC is fabricated with the silicon-on-insulator (SOI) bipolar-CMOS-DMOS (BCD) process, which occupied an area of 1.86 mm2.