Design of Remote Monitoring and Evaluation System for UPS Battery Performance

Chunjie Hou,Jiabin Wang,Chun Gao 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.5

For the case of each unit battery status parameter of UPS is unpredictable, this paper develops a remote monitoring system, through the connection of local monitoring software and remote monitoring software, interacting database and human-computer to complete this system. Practice has proved that this system can secure stable operation and better meet the requirements of the UPS battery remote monitoring technology.

Fault-Tolerant Control for 5L-HNPC Inverter-Fed Induction Motor Drives with Finite Control Set Model Predictive Control Based on Hierarchical Optimization

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.

Backward extensions of Bergman-type weighted shift

Chunji Li,Wentao Qi,Haiwen Wang 대한수학회 2020 대한수학회보 Vol.57 No.1

Let $m\in \mathbb{N}_{0}$, $p>1$ and $$\alpha ^{\left[ m,p\right] }\left( x\right) :\sqrt{x},\left\{ \sqrt{\frac{\left( m+n-1\right) p-\left( m+n-2\right) }{\left( m+n\right) p-\left( m+n-1\right) }}\right\} _{n=1}^{\infty }.$$ In this paper, we consider the backward extensions of Bergman-type weighted shift $W_{\alpha ^{\left[ m,p\right] }\left( x\right) }.$ We consider its subnormality, $k$-hyponormality and positive quadratic hyponormality. Our results include all the results on Bergman weighted shift $W_{\alpha \left( x\right) }$ with $m\in \mathbb{N}$ and $$\alpha \left( x\right) :\sqrt{x},\sqrt{\frac{m}{m+1}},\sqrt{\frac{m+1}{m+2}},\sqrt{\frac{ m+2}{m+3}},\ldots .$$

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.

BACKWARD EXTENSIONS OF BERGMAN-TYPE WEIGHTED SHIFT

Li, Chunji,Qi, Wentao,Wang, Haiwen Korean Mathematical Society 2020 대한수학회보 Vol.57 No.1

Let m ∈ ℕ₀, p > 1 and $${\alpha}^{[m,p]}(x)\;:\;{\sqrt{x}},\;\{{\sqrt{\frac{(m+n-1)p-(m+n-2)}{(m+n)p-(m+n-1)}}}\}^{\infty}_{n=1}$$. In this paper, we consider the backward extensions of Bergman-type weighted shift W_α^[m,p]_(x). We consider its subnormality, k-hyponormality and positive quadratic hyponormality. Our results include all the results on Bergman weighted shift W_α(x) with m ∈ ℕ and $${\alpha}(x)\;:\;{\sqrt{x}},\;{\sqrt{\frac{m}{m+1}},\;{\sqrt{\frac{m}{m+2}},\;{\sqrt{\frac{m+2}{m+3}},{\cdots}$$.

Fault-Tolerant Control for 5L-HNPC Inverter-Fed Induction Motor Drives with Finite Control Set Model Predictive Control Based on Hierarchical Optimization

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.

High Utility Itemset Mining over Uncertain Datasets Based on a Quantum Genetic Algorithm

( Ju Wang ),( Fuxian Liu ),( Chunjie Jin ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.8

The discovered high potential utility itemsets (HPUIs) have significant influence on a variety of areas, such as retail marketing, web click analysis, and biological gene analysis. Thus, in this paper, we propose an algorithm called HPUIM-QGA (Mining high potential utility itemsets based on a quantum genetic algorithm) to mine HPUIs over uncertain datasets based on a quantum genetic algorithm (QGA). The proposed algorithm not only can handle the problem of the non-downward closure property by developing an upper bound of the potential utility (UBPU) (which prunes the unpromising itemsets in the early stage) but can also handle the problem of combinatorial explosion by introducing a QGA, which finds optimal solutions quickly and needs to set only very few parameters. Furthermore, a pruning strategy has been designed to avoid the meaningless and redundant itemsets that are generated in the evolution process of the QGA. As proof of the HPUIM-QGA, a substantial number of experiments are performed on the runtime, memory usage, analysis of the discovered itemsets and the convergence on real-life and synthetic datasets. The results show that our proposed algorithm is reasonable and acceptable for mining meaningful HPUIs from uncertain datasets.

Response of sheep rumen fermentation and microbial communities to feed infected with the endophyte Epichloë gansuensis as evaluated with rumen-simulating technology

Ma Yaling,Wang Hucheng,Li Chunjie 한국미생물학회 2021 The journal of microbiology Vol.59 No.8

Achnatherum inebrians, a perennial grass, is widely distributed in China. When infected by the endophyte Epichloë gansuensis, A. inebrians produces an abundance of alkaloids that enhance plant survival but are toxic to animals. Here we used in vitro fermentation to study the impact of endophyte- infected A. inebrians (E+) addition on rumen fermentation characteristics and on microbial community and diversity as assessed with amplicon sequencing technology. We examined E+ addition at five levels, E0, E25, E50, E75, and E100, corresponding to 0%, 25%, 50%, 75%, and 100% of the fermentation substrate, respectively. Both the fermentation characteristics and rumen microbial community structure differed significantly among treatments. E100 resulted in the highest values for pH, the Shannon index, Kiritimatiellaeota, and Lentisphaerae levels relative to the other treatments. In contrast, E25 was associated with higher levels of ammonia nitrogen, total volatile fatty acid, propionate, butyrate, isobutyrate, valerate, of the phyla Bacteroidetes and Firmicutes, and of the genus Prevotella_1, Succiniclasticum, Family_XIII_AD3011_group, Rikenellaceae_RC9_gut_group, Prevotellaceae_UCG-001, and Pyramidobacter as compared with other treatments. E50 resulted in the greatest values for the abundance-based coverage estimator (ACE) and the Chao1 index as compared with other treatments. E0 resulted in the greatest values for digestibility of dry matter, gas production, acetate, and Ruminobacter as compared with other treatments. This approach avoided animal toxicity experiments and confirmed that rumen fermentation characteristics and rumen microbiota were affected by E+ toxin. Therefore, E25 showed higher abundance in Prevotella_1, Prevotellaceae_ UCG-001, and Lachnospiraceae_XPB1014_group that implied they should play significant roles in E+ alkaloids degradation. And then, we can infer that rumen microorganisms should function as an antidote with respect to this poisoning reaction at moderate dietary percentages of E+.

Accuracy analysis and error compensation for Tricept machine tool under load

Jianzhong Ding,Chunjie Wang 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.8

This paper provides an efficient way to estimate the accuracy performance of the Tricept machine tool under load. Both joint clearances and link flexibility are considered. Clearances of the spherical joints and universal joint are considered, and the small change in link length arisen from clearances and deformation is modeled with the hyperbolic function. The kinetostatic model for accuracy analysis is obtained by balancing the employed load and the elastic forces provided by limbs. Moreover, an error compensation method for the Tricept machine tool under load is presented. The proposed methods are further illustrated and validated using a study case, and the feasibility of the error compensation method is discussed. This paper gives a deep insight into the effects of clearances, flexibility and loads on the accuracy performance of the Tricept-like mechanisms and instructive conclusions are drawn for accuracy improvement.

Accuracy analysis of a parallel positioning mechanism with actuation redundancy

Jianzhong Ding,Chunjie Wang,Hongyu Wu 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.1

A forward accuracy analysis method based on Lie-group theory and screw theory is proposed to analyze the pose error of parallel mechanisms with actuation redundancy. Both the input uncertainty and components stiffness were considered. The method was applied to study the accuracy performance of a positioning mechanism, which has the potential to be used for the positioning of satellite antenna, camera, astronomical telescope and so on. The advancement of the method is that it models the elastic deformation and passive joint motions together by motion vector and limb stiffness matrix, which greatly simplifies the constraints modeling process. Mean value and standard deviation of the pose errors under different working conditions were obtained by optimal Latin hypercube sampling method, which reduces the sampling size on the premise of ensuring the precision. Finally, the robust optimization was employed to give further insight into the effects of redundant limb and mechanism structure on the accuracy performance of the actuation-redundant mechanism.