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Chunjie Li,Guifeng Wang,Fei Li,Hongmei Li,Zhenglong Xia,Zhan Liu 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.4
This paper proposes a fault-tolerant control strategy with finite control set model predictive control (FCS-MPC) based onhierarchical optimization for five-level H-bridge neutral-point-clamped (5L-HNPC) inverter-fed induction motor drives. Faulttolerantoperation is analyzed, and the fault-tolerant control algorithm is improved. Adopting FCS-MPC based on hierarchicaloptimization, where the voltage is used as the controlled objective, called model predictive voltage control (MPVC), the postfaultcontroller is simplified as a two layer control. The first layer is the voltage jump limit, and the second layer is the voltagefollowing control, which adopts the optimal control strategy to ensure the current following performance and uniqueness of theoptimal solution. Finally, simulation and experimental results verify that 5L-HNPC inverter-fed induction motor drives havestrong fault tolerant capability and that the FCS-MPVC based on hierarchical optimization is feasible.
Chunjie Zhao,Lu Bai,Huanxin Li,Fei Li,Chunhong Xin 대한약학회 2007 Archives of Pharmacal Research Vol.30 No.12
A method involving depuration of 12 organochlorine pesticides (OCPs) and 7 heavy metals from Epimedium brevicornum Maxim was developed using supercritical fluid extraction (SPE). The pesticides in the study consisted of α, β-, γ-, and δ-Benzene hexachloride, Pentachloronitrobenzene (PCNB ), Pentachloroaniline (PCA), Heptachlor (HEPT), Methyl -pentachlorophenyl sulfide (MPCPS), pp'-DDE[1,1-dichloro-2, 2-bis (p-chlorophenyl) ethylene], op'-DDT [1,1,1- trichloro-2-(o-chlorophenyl)-2-(p-chlorophenyl)ethane], pp'-DDD [1,1-dichloro-2-2-bis(p-chlorophenyl)] ethane, pp'-DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane]. A series of experiments was conducted to optimize the final extraction conditions as following: pure CO2, extraction pressure of 15 Mpa, extration temperature of 60oC, extraction time of 10 min, flow rate at 55 kg/h. A GC method with electron capture detection was employed to determination of the OCPs, and an atomic absorption spectrometry (AAS) was designed for the determination of 7 heavy metals including of Pb, Cd, Cu, Fe, Zn, As, Hg in Epimedium brevicornum Maxim. A HPLC method was developed for the quantitative determination of active constituents. The SFE was used to remove the organochlorine pesticide and heavy metals from Epimedium brevicornum Maxim, receiving high decontamination rate of pesticide residue and low loss of active constituents.
ESTIMATING THE DOMAIN OF ATTRACTION VIA MOMENT MATRICES
Li, Chunji,Ryoo, Cheon-Seoung,Li, Ning,Cao, Lili Korean Mathematical Society 2009 대한수학회보 Vol.46 No.6
The domain of attraction of a nonlinear differential equations is the region of initial points of solution tending to the equilibrium points of the systems as the time going. Determining the domain of attraction is one of the most important problems to investigate nonlinear dynamical systems. In this article, we first present two algorithms to determine the domain of attraction by using the moment matrices. In addition, as an application we consider a class of SIRS infection model and discuss asymptotical stability by Lyapunov method, and also estimate the domain of attraction by using the algorithms.
Estimating the domain of attraction via moment matrices
Chunji Li,유천성,Ning Li,Lili Cao 대한수학회 2009 대한수학회보 Vol.46 No.6
The domain of attraction of a nonlinear differential equations is the region of initial points of solution tending to the equilibrium points of the systems as the time going. Determining the domain of attraction is one of the most important problems to investigate nonlinear dynamical systems. In this article, we first present two algorithms to determine the domain of attraction by using the moment matrices. In addition, as an application we consider a class of SIRS infection model and discuss asymptotical stability by Lyapunov method, and also estimate the domain of attraction by using the algorithms. The domain of attraction of a nonlinear differential equations is the region of initial points of solution tending to the equilibrium points of the systems as the time going. Determining the domain of attraction is one of the most important problems to investigate nonlinear dynamical systems. In this article, we first present two algorithms to determine the domain of attraction by using the moment matrices. In addition, as an application we consider a class of SIRS infection model and discuss asymptotical stability by Lyapunov method, and also estimate the domain of attraction by using the algorithms.
Li, Chunjie,Wang, Guifeng,Li, Fei,Li, Hongmei,Xia, Zhenglong,Liu, Zhan The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.4
This paper proposes a fault-tolerant control strategy with finite control set model predictive control (FCS-MPC) based on hierarchical optimization for five-level H-bridge neutral-point-clamped (5L-HNPC) inverter-fed induction motor drives. Fault-tolerant operation is analyzed, and the fault-tolerant control algorithm is improved. Adopting FCS-MPC based on hierarchical optimization, where the voltage is used as the controlled objective, called model predictive voltage control (MPVC), the postfault controller is simplified as a two layer control. The first layer is the voltage jump limit, and the second layer is the voltage following control, which adopts the optimal control strategy to ensure the current following performance and uniqueness of the optimal solution. Finally, simulation and experimental results verify that 5L-HNPC inverter-fed induction motor drives have strong fault tolerant capability and that the FCS-MPVC based on hierarchical optimization is feasible.
Fault-tolerant analysis of two boost inverters for open-end winding induction motor drives
Li, Chunjie,Wang, Guifeng,Li, Hongmei,Li, Fei,Xia, Zhenglong,Liu, Zhan The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.4
An open-end winding induction motor drive system fed by two boost inverters with fault-tolerant capability is presented to improve the reliability and safety of the drive system. The boost inverters consist of an impedance-source network and a two-level inverter. It can realize the boost/buck function. An analysis of its fault-tolerance is presented in detail. Short circuits and open circuits are commonly considered as the two main types of faults. Therefore, the fault types of the dual boost inverters are analyzed and diagnosed. Then, two different fault-tolerant schemes are presented. The presented fault-tolerant inverters are restructured through the power switch itself. In addition, different SVPWM methods are addressed. A simulation model and an experimental platform are constructed. Simulation and experimental results verify the fault tolerance of the drive system.
Zhao, Chunjie,Bai, Lu,Li, Huanxin,Li, Fei,Xin, Chunhong 대한약학회 2007 Archives of Pharmacal Research Vol.30 No.12
A method involving depuration of 12 organochlorine pesticides (OCPs) and 7 heavy metals from Epimedium brevicornum Maxim was developed using supercritical fluid extraction (SPE). The pesticides in the study consisted of ${\alpha},\;{\beta}-,\;{\gamma}-,\;and\;{\delta}-Benzene$ hexachloride, Pentachloronitrobenzene (PCNB), Pentachloroaniline (PCA), Heptachlor (HEPT), Methyl -pentachlorophenyl sulfide (MPCPS), pp'-DDE[1,1-dichloro-2, 2-bis (p-chlorophenyl) ethylene], op'-DDT [1,1,1-trichloro-2-(o-chlorophenyl)-2-(p-chlorophenyl)ethane], pp'-DDD [1,1-dichloro-2-2-bis(p-chlorophenyl)]ethane, pp'-DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane]. A series of experiments was conducted to optimize the final extraction conditions as following: pure $CO_2$, extraction pressure of 15 Mpa, extration temperature of $60^{\circ}C$, extraction time of 10 min, flow rate at 55 kg/h. A GC method with electron capture detection was employed to determination of the OCPs, and an atomic absorption spectrometry (AAS) was designed for the determination of 7 heavy metals including of Pb, Cd, Cu, Fe, Zn, As, Hg in Epimedium brevicornum Maxim. A HPLC method was developed for the quantitative determination of active constituents. The SFE was used to remove the organochlorine pesticide and heavy metals from Epimedium brevicornum Maxim, receiving high decontamination rate of pesticide residue and low loss of active constituents.
ESTIMATING THE DOMAIN OF ATTRACTION OF HIV-1 SYSTEM BASED ON MOMENT METHOD
Chunji Li,Han Yao 한국전산응용수학회 2018 Journal of applied mathematics & informatics Vol.36 No.5
In this article, we discuss the domain of attraction of HIV-1 system by using the moment theory. First, the asymptotic stabilities of the equilibrium point of the system are given, and then we introduce how to use the moment method to estimate domain of attraction. Finally, one simulation shows the eectiveness of moment method.