Predictive direct torque control of permanent magnet synchronous motors using deadbeat torque and flux control

Ao Wang,Housheng Zhang,Junjie Jiang,Duo Jin,Shengjie Zhu 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.2

In consideration of the shortcomings of the large torque and flux ripples in direct torque control (DTC), and the insufficient utilization of the duty cycle module in traditional DTC based on the duty cycle modulation of PMSMs, a DTC method based on deadbeat control of the torque and flux is proposed in this paper. In the synchronous rotation, coordinate system positioned with the stator flux vector, the reference voltage vector is calculated in accordance to the deadbeat control method. Six virtual voltages are constructed in such a manner that two adjacent basic voltage vectors are evenly divided in one control cycle. The effective voltage vectors are expanded to 12. The effective voltage vector closest to the phase angle of the reference voltage vector is determined to be the optimal voltage vector. Then, the duty cycle is introduced to further reduce the error between the final output voltage vector and the voltage vector required by the system. Simulation comparisons are carried out for DTC, traditional DTC based on duty cycle modulation, and the proposed DTC. The obtained simulation results demonstrate that the proposed DTC can effectively suppress both torque ripple and flux ripple, improve the utilization rate of the duty cycle module, and reduce the stator current distortion rate.

An I-Shaped Slot Grid Antenna Array with Substrate Integration and Enhanced Bandwidth

Zhiyi Li,Shengjie Wang,Fan Li,Lin Lin,Hongzheng Zeng 한국전자파학회JEES 2023 Journal of Electromagnetic Engineering and Science Vol.23 No.5

A Quantitative Method for Seismic Robustness of RC Frame Considering Resistance Vulnerability of Column and Storey Drift Ratios

Guohua Sheng,Shengji Jin,Lintao Ma,Quan Bai,Chao Xu,Xiaoyu Wang 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.1

The concept of seismic robustness is proposed by combining the concept of seismic performance and structural robustness. The existing qualitative, quantitative and evaluation methods of seismic robustness are all direct researched on the whole structure, and the influence mechanism of its internal components on the overall seismic robustness is still unclear. It is very important to establish a clear relationship between component design and structural seismic robustness for the structural design, reinforcement design and final evaluation of structural seismic robustness. Based on this, taking the column as the starting point, a quantitative method for the seismic robustness of RC frame by the seismic robustness index is proposed, which takes into account the resistance vulnerability of column and influence of column on the storey drift ratios (SDRs). In which, the resistance vulnerability is represented by the defined control vulnerability coefficient Pimax, and the influence on the SDRs are represented by the storey drift ratio importance coefficients (SDRCs) . The method not only reflects the essential mechanical properties of the column, but also reflects the effects brought about by different SALs. The feasibility of the method is demonstrated by numerical examples of two types of failures (assuming single column and two columns failure), and four optimization design proposals are proposed for it. The analysis shows that  of the target columns to the floor where the target columns located are obviously greater than those on the remaining floors of the target frame. The seismic robustness index R decreases sharply with the increase of the seismic action level (SAL). R is different compare single column failure with two columns failure under 4 SALs. The most effective way to improve the R of the frame under a certain SAL is to retrofit its control column.

Compressive-Tensile Mechanics and Energy Consumptions of a Cementitious Composite with High Utilization of Steel Slag

Guohua Sheng,Shengji Jin,Chao Li,Quan Bai,Xiaoyu Wang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.3

In response to the National Development and Reform Commission's “Guiding Opinions on Comprehensive Utilization of Large Solid Wastes during the Fourteenth Five Year Plan”, further expand the use of steel slag as concrete admixture in construction projects and other fields, and gradually improve the comprehensive utilization ratio, a cementitious composite with high utilization of steel slag (CHS) was developed, which is with the cement replaced by high-content super-fine steel slag powder (SSP) (replacement ratio υ ≥ 30%) as the cementitious materials, steel slag sand (SS) as the only aggregate and environmentally basalt fiber (BF) for toughening. It improves the utilization percentage of steel slag (SSP and SS) and reduces the consumption of natural resources such as cement and natural sand. Use BF to achieve better strength and toughness. In order to better understand the performance of CHS and make it better used in the engineering field. Study the influence of each component on the strength and energy consumption of compression and splitting tension, and strive to find the optimal proportion and lay the theoretical foundation for its application. Through the tests, the effects of high replacement ratio υ (30% − 50%), low binder-aggregate ratio γ (0.31 − 0.44), and BF content ρv (0% − 2%) on the aspects of peak strength, force-deformation curve and energy consumption were analyzed. The results show that the standard curing fck and ft,s can reach 40 MPa and 5 MPa respectively. With the increase of υ, the maximum axial compressive strength fck and splitting tensile strength ft,s decreased insignificantly. The γ has an important influence on fck and ft,s. When it increases from 0.31 to 0.44, fck increases linearly by 63.1% to 40.4 MPa, while ft,s increases by 52.8% to 5.18 MPa. As ρv increases, fck and ft,s show a trend of first increasing and then decreasing. ρv exerts a significant impact on the descending segments of stress-strain response curves of the compression which expressed as bilinear and trilinear models with different ρv after normalization. The energy consumptions of peak, total, and residual (Epeak, Edisp, Eres) show a slight downward trend with the increase of υ, a significantly upward trend with the increase of γ. With the increase of γv, Epeak and Edisp increase first and then tend to be flat, while Eres always increases and the percentages of Eres/Edisp in the compressive test increase from 22.6% to 38.5%, reflecting the improvement of the compressivetoughness of BF.

PsnERF75 Transcription Factor from Populus simonii × P. nigra Confers Salt Tolerance in Transgenic Arabidopsis

Tingbo Jiang,Shengji Wang,Boru Zhou,Wenjing Yao 한국식물학회 2018 Journal of Plant Biology Vol.61 No.2

ERF transcription factor involves in many aspectsof plant development and response to both biotic and abioticenvironmental stimuli. In this study, we provided evidencethat PsnERF75 can improve the salt tolerance ability oftransgenic Arabidopsis. RT-qPCR analysis described thespatio-temporal expression patterns of PsnERF75 in differentpoplar tissues. Under salt stress condition, root and leaftissues were more sensitive than stem tissue. In addition,seed germination rates of PsnERF75 transgenic Arabidopsiswere significantly enhanced. Growth status of PsnERF75transgenic Arabidopsis seedlings was much better than thatof the controls. Physiological and histochemical assaysindicated PsnERF75 transgenic Arabidopsis have a greatercapacity to eliminate reactive oxygen species and lighten thedamages to plants than the controls. Using RNA-seq analysis,100 DEGs that were significant differentially expressedbetween PsnERF75 transgenic Arabidopsis and the controlsunder salt stress conditions were identified. Seventeen upregulatedand 10 down-regulated DEGs participate in plantsalt stress response process. In addition, subcellular localizationshowed that PsnERF75 is a nuclear-localized protein. All ofthe results will provide novel insights into the functions ofERF75 in plants under abiotic stress condition.

Unified coordinated control strategy for two parallel inverters TPOW‑PMSM system

Housheng Zhang,Shengjie Zhu,Duo Jin,Ao Wang,Junjie Jiang,Lanlan Yu 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.2

The three-phase open-winding permanent magnet synchronous motor (TPOW-PMSM) is generally used to drive electric vehicles. The voltage vector spatial distribution and fault-tolerant topological structure of a TPOW-PMSM system with two parallel inverters are analyzed in this paper. Then, based on the unified PWM modulation algorithm, a unified coordinated control strategy based on reference voltage vector 120º decoupling control is proposed. The speed and current double closedloop control systems of two parallel inverters are designed, and a PI + repetitive controller of the speed loop is designed to realize fast and stable speed control. The realization process does not require sector judgment or table lookup calculations, and the switching time of each bridge arm switch tube is determined by the instantaneous value of the three-phase voltage of the two parallel inverters, which simplifies the control algorithm. Experimental results show that the unified coordinated control strategy with the PI + repetitive controller can control the normal operation of a TPOW-PMSM, and realize smooth and reliable transitions from the normal operation state to the fault-tolerant operation state. The proposed unified coordinated control strategy with the PI + repetitive controller effectively suppresses the instantaneous value of system zero-sequence current, and inhibits the influence of the dead zone effect.

Simplified model prediction current control strategy for permanent magnet synchronous motor

Zhang, Housheng,Zhu, Shengjie,Jiang, Junjie,Wang, Qingzhuang,Wang, Ao,Jin, Duo The Korean Institute of Power Electronics 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.11

A simplified model predictive current control strategy based on mathematical auxiliary line method is proposed to increase the permanent magnet synchronous motor (PMSM) predictive current control system's steady-state performance while reducing the system's computational complexity. The mathematical models of current prediction, first-order compensation, and cost function are presented by analyzing the prediction current control strategy of the conventional models. Within a control cycle, the simplified model predictive current control algorithm applies two voltage vectors and omits the error calculation of cost function. The anticipated voltage of transformer obtained from the beat-free current control standard is considered the reference voltage, and the judgment of the area, where the reference voltage vector is found and the strategy for double voltage vector is selected, is put forward. The optimal voltage vector can be directly output without the error calculation of the cost function in the method, thereby effectively reducing the computation load and complexity of the system and improving the steady-state performance. Experimental results verify the validity and accuracy of the proposed simplified model of predictive current control strategy for PMSM control.

Investigation of the concentration characteristic of RCS during the boration process using a coupled model

Chi Xiangyu,Li Shengjie,Gu Mingzhou,Li Yaru,Zhu Xixi,Wang Naihua 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.8

The fluid retention effect of the Volume Control Tank (VCT) leads to a long time delay in Reactor Coolant System (RCS) concentration during the boration process. A coupled model combining a lumpedparameter sub-model and a computational fluid dynamics sub-model is currently used to investigate the concentration dynamic characteristic of RCS during the boration process. This model is validated by comparison with experimental data, and the predicted results show excellent agreement with experimental data. We provide detailed fields in VCT and concentration variations of RCS to study the interaction between mixing in VCT and the transient responses of RCS. Moreover, the impacts of the inlet flow rate, inlet nozzle diameter, original concentration, and replenishing temperature of VCT on the RCS concentration characteristic are studied. The inlet flow rate and nozzle diameter of VCT remarkably affect the RCS concentration characteristic. Too-large or too-small inlet flow rates and nozzle diameters will lead to unacceptable long delays. In this work, the optimal inlet flow rate and nozzle diameter of VCT are 5 m3 /h and 58.8 mm, respectively. Besides, the impacts of the original concentration and replenishing temperature of VCT are negligible under normal operating conditions.

Effect of Annealing on the Microstructure, Texture and Tensile Deformation Properties of Cu–3 wt%Ag–0.5 wt%Zr Thin Sheets Rolled at Room and Cryogenic Temperature

Peng Zhang,Han Wang,ShengJie Yao,ChuanJie Wang,Qiang Zhu,Gang Chen 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.2

The Cu–3 wt%Ag–0.5 wt%Zr are rolled with the same reduction process at room (RT) and cryogenic (CT) temperature,respectively. The electron backscatter diffraction and transmission electron microscope are used to analyze and comparethe evolutions of material microstructure and texture. The results show that the stability of as-rolled CT sheets is differentfrom that of the RT samples, which can be verified by the lower temperature for the occurrence of recrystallization andAg-base particles precipitation. Besides the Brass, Copper and S textures which are exhibited in the two kinds of as-rolledsheets, there are also Q and P texture components in the as-rolled CT sheets. The constitutive equation basing on evolutionof dislocation mean free path (L) and dislocation cell size (dDC) with plastic strain indicates that the initial values of L, dDCand mobile dislocation density (ρm) are associated with annealing condition closely. Furthermore, the strain ranges of thestable and instable plastic deformation are related to the degree of recovery and recrystallization.

miR-101-3p/Rap1b signal pathway plays a key role in osteoclast differentiation after treatment with bisphosphonates

( Jie Li ),( You Li ),( Shengjie Wang ),( Hui Che ),( Jun Wu ),( Yongxin Ren ) 생화학분자생물학회(구 한국생화학분자생물학회) 2019 BMB Reports Vol.52 No.9

Bisphosphonates are the mainstay of therapy worldwide for osteoporosis. However, bisphosphonates also have limitations. The objective of this study was to determine the role of miR-101-3p/Rap1b signal pathway in osteoclast differentiation after treatment with bisphosphonates. Our results revealed that miR-101-3p was an important regulator in bisphosphonates treated-osteoclasts. When miR-101-3p was down-regulated in bone marrow-derived macrophage-like cells (BMMs), the development of mature osteoclasts was promoted, and vice versa. However, alendronate decreased multinucleated cell number regardless of whether miR-101-3p was knocked down or over-expressed. TRAP activity assay confirmed the above results. Luciferase assay indicated that miR-101-3p was a negative regulator of Rap1b. Western blot analysis revealed that protein expression level of Rap1b in BMMs transfected with OV-miR-101-3p was lower than that in BMMs transfected with an empty vector. Rap1b overexpression increased TRAP-positive multinucleated cells, while Rap1b inhibition decreased the cell numbers. In vivo data showed that miR-101-3p inhibited osteoclast differentiation in ovariectomized mice while overexpressed of Rap1b blocked the differentiation. Taken together, our data demonstrate that miR-101-3p/Rap1b signal pathway plays a key role in osteoclast differentiation after treatment with bisphosphonates. [BMB Reports 2019; 52(9): 572-576]