Hybrid PWM Modulation Technology Applied to Three-Level Topology-Based PMSMs

Chen, Yuanxi,Guo, Xinhua,Xue, Jiangyu,Chen, Yifeng The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.1

The inverter is an essential part of permanent magnet synchronous motor (PMSM) drive systems. The performance of an inverter is greatly influenced by its modulation strategy. Using a proper management of modulation strategies can guarantee high performance from a PMSM under various speed conditions. Switching between modulations is a pivotal technique that determines the performance of a PMSM. Most works on hybrid methods focus on two-level induction motors drive systems. In this paper, in order to improve the performance of PMSMs under various speed conditions, a hybrid method of a pulse width modulation (PWM) control scheme based on a neutral-point-clamped (NPC) three level topology was proposed. This hybrid PWM modulation comprised space vector PWM (SVPWM) and selective harmonic elimination PWM (SHEPWM). Under low speed conditions, the SVPWM is employed to cause the PMSM to start smoothly, and to obtain a rapid response from the control system. Under high speed conditions, the SHEPWM is employed to reduce the switching frequency and to eliminate particular current harmonics. Moreover, the harmonic characteristics of different modulations are analyzed to obtain a smooth transition between the SHEPWM and the SVPWM. Experimental and simulation results indicated the effectiveness of the proposed control method.

Hybrid PWM Modulation Technology Applied to Three-Level Topology-Based PMSMs

Yuanxi Chen,Xinhua Guo,Jiangyu Xue,Yifeng Chen 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.1

The inverter is an essential part of permanent magnet synchronous motor (PMSM) drive systems. The performance of aninverter is greatly influenced by its modulation strategy. Using a proper management of modulation strategies can guarantee highperformance from a PMSM under various speed conditions. Switching between modulations is a pivotal technique thatdetermines the performance of a PMSM. Most works on hybrid methods focus on two-level induction motors drive systems. Inthis paper, in order to improve the performance of PMSMs under various speed conditions, a hybrid method of a pulse widthmodulation (PWM) control scheme based on a neutral-point-clamped (NPC) three level topology was proposed. This hybridPWM modulation comprised space vector PWM (SVPWM) and selective harmonic elimination PWM (SHEPWM). Under lowspeed conditions, the SVPWM is employed to cause the PMSM to start smoothly, and to obtain a rapid response from the controlsystem. Under high speed conditions, the SHEPWM is employed to reduce the switching frequency and to eliminate particularcurrent harmonics. Moreover, the harmonic characteristics of different modulations are analyzed to obtain a smooth transitionbetween the SHEPWM and the SVPWM. Experimental and simulation results indicated the effectiveness of the proposed controlmethod.

Effects of Huzhangoside C on Dextran Sodium Sulfate-Stimulated Colitis in Mice

Limin Chen,Yonghong Zhang,Jinhuang Shen,Ying Wu,Fan Cao,Hongying Hua,Xinhua Ma 한국식품영양과학회 2024 Journal of medicinal food Vol.27 No.1

Chronic inflammation is a major risk factor for cancer. Inflammatory bowel disease (IBD) is a chronicinflammatory disease of the gastrointestinal tract, ultimately leading to a breakdown of intestinal barrier function. Clematisflorida var. plena is a folk prescription used to treat inflammation and rheumatism in She pharmacy. The bioactivity of C. florida var. plena is primarily due to triterpene saponins. Huzhangoside C (HZ) is an active component of C. florida var. plena. In this study, the anti-inflammatory effect of HZ on a mouse colitis model induced by dextran sulfate sodium (DSS) wasinvestigated. Result indicated a notable reduction in body weight loss and colon length shortening in HZ-mediated micecompared to DSS-stimulated control mice. Furthermore, inflammatory signaling mechanisms involving interleukin-6 andtumor necrosis factor-a were suppressed in HZ-treated mice. HZ treatment significantly suppressed the expression of nuclearfactor kappa B (NF-jB), STAT3, and iNOS in colon tissue. After HZ treatment, malondialdehyde and nitric oxide levels weresignificantly decreased, while Nrf-2, superoxide dismutase, and glutathione expression levels were notably improved. Theresult indicated that HZ could activate the Nrf-2 signal cascade, inhibit the expression of NF-jB, eNOS, and STAT3, andenhance the intestinal barrier function of DSS stimulated ulcerative colitis intestinal injury. The results suggest that HZ ispotential anti-inflammatory agent for treating IBD.

Alkylation of anthracene to 2-isopropylanthracene catalyzed by Lewis acid ionic liquids

Min Chen,Ying Luo,Guofang Li,Minqiang He,Jimin Xie,Huamin Li,Xinhua Yuan 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.6

Alkylation of anthracene with 2-chloropropane to 2-isopropylanthracene catalyzed by various Lewis acidic ionic liquids (ILs), such as [Emim]Cl-AlCl3, [Emim]Cl-FeCl3, [Emim]Cl-ZnCl2, [Bmim]Cl-AlCl3, and [Omim]Cl-AlCl3 ([Emim]+=1-ethyl-3-methylimidazolium cation, [Bmim]+=1-butyl-3-methylimidazolium cation, [Omim]+=1-octyl-3- methylimidazolium cation,), was investigated. [Emim]C1-A1C13 ionic liquid was found to be the most active catalyst in the alkylation. The yield of 2-isopropylanthracene was up to 74.5% and the selectivity of 2-isopropylanthracene was up to 82.9%. The [Emim]C1-A1C13 ionic liquid catalyst showed good catalytic activity after running for 6 times. Ease of product separation and the recycling performance of the ionic liquid catalyst is expected to contribute to the development of clean and environmentally friendly strategy for the synthesis of 2-isopropylanthracene.

Synthesis of 5-benzoylacenaphthene in the presence of Lewis acidic ionic liquids

Min Chen,Di Li,Ying Luo,Minqiang He,Jimin Xie,Huamin Li,Xinhua Yuan 한국공업화학회 2011 Journal of Industrial and Engineering Chemistry Vol.17 No.1

Acylation of acenaphthene with benzoyl chloride to 5-benzoylacenaphthene catalyzed by various Lewis acidic ionic liquids (ILs) was investigated. Ionic liquids of different alkyl chain length and metal chloride were synthesized and tested for the reaction to discuss the effects of Lewis acidity of the ionic liquid on the synthesis of 5-benzoylacenaphthene. Pure 5-benzoylacenaphthene was obtained and its structure was identified by GC/MS, FT-IR and 1H NMR spectra. [Emim]Cl/AlCl3 ionic liquid was found to be the most active catalyst in the acylation. The yield of 5-benzoylacenaphthene was up to 87% and the regioselectivity towards 5-benzoylacenaphthene was up to 90%. The experimental resulted show that [Emim]Cl/AlCl3 can be used as both catalyst and solvent, and it is reusable and environmentally friendly for the preparation of 5-benzoylacenaphthene.

Overview of Active Disturbance Rejection Control for Permanent Magnet Synchronous Motors

Zhang Xinhua,Chen Yujia,Sun Xiaodong 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.3

The ubiquitous implementation of permanent magnet synchronous motors (PMSMs) in contemporary alternating current propulsion systems is widely acknowledged. As a superior control method that does not rely on a precise system mathematical model and has superior robustness, Active Disturbance Rejection Control (ADRC) is widely used to improve the overall control performance and efciency of the PMSM drive system. Starting from three parts of ADRC, this paper comprehensively expounds on the advantages of the ADRC control strategy and its shortcomings in the application at present. The problems of too many parameters, not easily controlling the nonlinear part, and difculty in adjusting the parameters are summarized. Then the performance improvement schemes of ADRC such as structure optimization, parameter tuning, nonlinear part optimization, and simplifed parameters are summarized. Finally, the future development trend of the control algorithm is forecasted.

Development of a stable and efficient zein based nanopesticides through green and simple way for improving utilization efficiency

Dai Xiuchun,Chen Long,Zhou Hongjun,Zhou Xinhua 한국응용곤충학회 2022 Journal of Asia-Pacific Entomology Vol.25 No.2

Nanopesticides represent one of the effective ways of reducing the use of pesticides and the environmental pollution. Natural zein as a potential carrier for nanoencapsulation of pesticides has the disadvantages of large amount of organic solvents and poor dispersibility. In this study, a water soluble of zein peptides was obtained by hydrolyzed under alkaline conditions with heated and stability of nanopesticides were prepared through crosslinked after self-assemble. As the results, the zein peptides spontaneously assembled into spherical particles in an aqueous solution, the nanopesticides (avermectin, AVM), with uniform size distribution and size can be adjusted by the glutaraldehyde, have a great stability, and redispersed in water after freeze-drying. Moreover, nanoencapsulation protects avermectin from UV light, with 24% of the encapsulated AVM remaining intact after exposure to UV for 60 min, compared to less than 6% for the bare AVM. In addition, the nanoformulation had similar insecticidal activity to commercial EC and the cross-linking of particles slowed down the release rate and the curves were consistent with Higuchi model different from the abnormal diffusion in the uncross linked state. In short, this study provides a simple method to obtain stabilizable nanopesticides based on natural polymer on a green way.

Regioselective Nitration of Inactive 4,4-Dibromobiphenyl with Nitrogen Dioxide and Molecular Oxygen over Zeolites: An Efficient Preparation of 4,4'-Dibromo-2-nitrobiphenyl

Wang, Wei,Peng, Xinhua,Chen, Nan Korean Chemical Society 2014 대한화학회지 Vol.58 No.1

In the presence of zeolites, 4,4'-dibromobiphenyl could be region-selectively nitrated by the action of nitrogen dioxide and molecular oxygen. The ratio of 4,4'-dibromo-2-nitrobiphenyl to 4,4'-dibromo-3-nitrobiphenyl could reach 14 in a high yield of 90%. Zeolites could be easily regenerated by heating and reused four times to give the results similar to those obtained with fresh catalyst. Compared with the classic nitration method, no nitric acid and sulfuric acid were used, which suggested that the method was an environmentally economic process.

Effects of regeneration conditions on sulfated CuSSZ-13 catalyst for NH3-SCR

Meiqing Shen,Zhixin Wang,Xinhua Li,Jiaming Wang,Jianqiang Wang,Chen Wang,Jun Wang 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.8

To understand the role of regeneration conditions on sulfur-poisoned Cu/SSZ-13 catalysts for NH3-SCR, the physicochemical characterizations and NOx conversions were investigated. The sulfur-poisoned Cu/SSZ-13 catalysts were treated at different conditions as a function of temperature and duration. TGA results revealed that regeneration at 500 oC only removed parts of sulfur spices and at 700 oC can completely remove all sulfur spices. The physical structural characterizations results illustrate that regeneration below 700 oC has no significant impact on CHA structure for Cu/SSZ-13 catalysts, while dealumination occurs on poisoned Cu/SSZ-13 when regeneration temperature is higher than 700 oC. EPR and H2-TPR results show that the sulfate decomposition and Cu migration reactions involved during regeneration and, as a result, the content of Cu2+ gradually increased as the extent of regeneration increased. The kinetics tests support that NOx conversion recovery is related to the content of Cu2+ increase during regeneration. Our study reveals that the optimum regeneration temperature is 700 oC, because severe dealumination at 750 oC inhibited Cu2+ amount increase.

Speed Dependent Tool Point Dynamics Prediction By RCSA

Yingang Chai,Yong Chen,Xinhua Long 한국생산제조학회 2014 한국생산제조시스템학회 학술발표대회 논문집 Vol.2014 No.9(2)