Model Predictive Torque Control of Surface Mounted Permanent Magnet Synchronous Motor Drives with Voltage Cost Functions

Zhang, Xiaoguang,Hou, Benshuai,He, Yikang,Gao, Dawei The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.5

In this paper, a model predictive torque control (MPTC) without the use of a weighting factor for surface mounted permanent-magnet synchronous machine (SPMSM) drive systems is presented. Firstly, the desired voltage vector is predicted in real time according to the principles of deadbeat torque and flux control. Then the sector of this desired voltage vector is determined. The complete enumeration for testing all of the feasible voltage vectors is avoided by testing only the candidate vectors contained in the sector. This means that only two voltage vectors in the sector need to be tested for selecting the optimal voltage vector in each control period. Thus, the calculation time can be reduced when compared with the conventional enumeration method. On the other hand, a novel cost function that only includes the dq-axis voltage errors between the desired voltage and candidate voltage is designed to eliminate the weighting factor used in the conventional MPTC. Thus, the control complexity caused by the tuning of the weighting factor is effectively decreased when compared with the conventional MPTC. Simulation and experimental investigation have been carried out to verify the proposed method.

Double Vector Based Model Predictive Torque Control for SPMSM Drives with Improved Steady-State Performance

Zhang, Xiaoguang,He, Yikang,Hou, Benshuai The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.5

In order to further improve the steady-state control performance of model predictive torque control (MPTC), a double-vector-based model predictive torque control without a weighting factor is proposed in this paper. The extended voltage vectors synthesized by two basic voltage vectors are used to increase the number of feasible voltage vectors. Therefore, the control precision of the torque and the stator flux along with the steady-state performance can be improved. To avoid testing all of the feasible voltage vectors, the solution of deadbeat torque control is calculated to predict the reference voltage vector. Thus, the candidate voltage vectors, which need to be evaluated by a cost function, can be reduced based on the sector position of the predicted reference voltage vector. Furthermore, a cost function, which only includes a reference voltage tracking error, is designed to eliminate the weighting factor. Moreover, two voltage vectors are applied during one control period, and their durations are calculated based on the principle of reference voltage tracking error minimization. Finally, the proposed method is tested by simulations and experiments.

Double Vector Based Model Predictive Torque Control for SPMSM Drives with Improved Steady-State Performance

Xiaoguang Zhang,Yikang He,Benshuai Hou 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.5

In order to further improve the steady-state control performance of model predictive torque control (MPTC), a double-vectorbased model predictive torque control without a weighting factor is proposed in this paper. The extended voltage vectors synthesized by two basic voltage vectors are used to increase the number of feasible voltage vectors. Therefore, the control precision of the torque and the stator flux along with the steady-state performance can be improved. To avoid testing all of the feasible voltage vectors, the solution of deadbeat torque control is calculated to predict the reference voltage vector. Thus, the candidate voltage vectors, which need to be evaluated by a cost function, can be reduced based on the sector position of the predicted reference voltage vector. Furthermore, a cost function, which only includes a reference voltage tracking error, is designed to eliminate the weighting factor. Moreover, two voltage vectors are applied during one control period, and their durations are calculated based on the principle of reference voltage tracking error minimization. Finally, the proposed method is tested by simulations and experiments.

Model Predictive Torque Control of Surface Mounted Permanent Magnet Synchronous Motor Drives with Voltage Cost Functions

Xiaoguang Zhang,Benshuai Hou,Yikang He,Dawei Gao 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.5

In this paper, a model predictive torque control (MPTC) without the use of a weighting factor for surface mounted permanentmagnet synchronous machine (SPMSM) drive systems is presented. Firstly, the desired voltage vector is predicted in real time according to the principles of deadbeat torque and flux control. Then the sector of this desired voltage vector is determined. The complete enumeration for testing all of the feasible voltage vectors is avoided by testing only the candidate vectors contained in the sector. This means that only two voltage vectors in the sector need to be tested for selecting the optimal voltage vector in each control period. Thus, the calculation time can be reduced when compared with the conventional enumeration method. On the other hand, a novel cost function that only includes the dq-axis voltage errors between the desired voltage and candidate voltage is designed to eliminate the weighting factor used in the conventional MPTC. Thus, the control complexity caused by the tuning of the weighting factor is effectively decreased when compared with the conventional MPTC. Simulation and experimental investigation have been carried out to verify the proposed method.

Level Set Based Path Planning Using a Novel Path Optimization Algorithm for Robots

Xiaoguang Zhang,Wei Zhang,Hui Li,Mingqin Liu,류성기 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.19 No.9

In order to decrease the path length and control the minimum distance between the path and the obstacles when the level set based path planning algorithm is adopted , a new path optimization algorithm named elastic particle is proposed in this paper. Firstly, the iteration expression of optimization algorithm is deduced by active contour theory. Secondly, to ensure the convergence of algorithm, the relation among each item in the algorithm expression is analyzed and its convergence condition is determined. At last, level set algorithm is improved so that the smoothness of the initial path and the convergence speed of the algorithm are improved. In addition, a method named the nearest boundary distance is put forward to accelerate the operation speed of the algorithm. What’s more, memory pool and binary sort tree are adopted in the code to further reduce the running time of this algorithm. The optimal values of the algorithm parameters are analyzed via the simulation experiment,and its result demonstrates that the new algorithm has greatly optimized the path of algorithm-level set and guaranteed fast running speed and high reliability.

Numerical Parametric Analysis of the Ultimate Loading-Capacity of Channel Purlins with Screw-Fastened Sheeting

Yingying Zhang,Jigang Xue,Xiaoguang Song,Qilin Zhang 한국강구조학회 2018 International Journal of Steel Structures Vol.18 No.5

This paper presents the numerical parametric analysis on the loading capacity of Channel purlins with screw-fastened sheeting, in which the eff ects of anti-sag bar and corrugated steel sheet on the ultimate capacity are studied. Results show that the setup of anti-sag bars can reduce the deformations and improve the ultimate capacity of C purlins. The traditional method of setting the anti-sag bars in the middle of the web is favorable. The changing of sheeting type, sheeting thickness and rib spacing has signifi cant eff ects on the ultimate capacity of C purlins without anti-sag bars, compared with those with anti-sag bars. The proposed design formulas are relatively consistent with the calculations of EN 1993-1-3:2006, which is diff erent from those of GB 50018-2002.

Failure Modes and Loading Bearing Capacity of Corrugated Steel Roofs Connected by Standing Seam Clips

Song Xiaoguang,Zhang Yingying,Zhang Qilin 한국강구조학회 2017 International Journal of Steel Structures Vol.17 No.4

This paper presents the research on failure modes and loading bearing capacity of two types of purlin-sheet roofs under uniform loadings. The full-size experiments are carried out on the purlin-sheet roofs and the allowable design stress and design proposals are proposed. Besides, the finite element analysis is conducted to compare with the experiments. Results show that the failure modes and loading bearing capacity of two types of purlin-sheet roofs are different. The first is that the adjustments are pulled out from the base, while the mechanical occlusions between the adjacent sheet and adjustments are well. The latter is that the mechanical occlusions between the adjustment and sheets are tensioned fracture, while the adjustment are tensioned straight and pulled out from the sheets. The numerical calculations and experiment data are in good agreement, and the deviations are mainly because of initial defects of specimens, construction errors of specimens and loading protocols. The numerical calculation method is reliable and can be used to analyze the sheet-purlin roof connected by standing seam clips.

Dynamic characteristics and wind-induced vibration coefficients of purlin-sheet roofs

Yingying Zhang,Xiaoguang Song,Qilin Zhang 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.22 No.5

This paper presents the dynamic characteristics analysis of the purlin-sheet roofs by the random vibration theories. Results show that the natural vibration frequency of the purlin-sheet roof is low, while the frequencies and mode distributions are very intensive. The random vibration theory should be used for the dynamic characteristics of the roof structures due to complex vibration response. Among the first 20th vibration modes, the first vibration mode is mainly the deformations of purlins, while the rest modes are the overall deformations of the roof. In the following 30th modes, it mainly performs unilateral local deformations of the roof. The frequency distribution of the first 20th modes varies significantly while those of the following 30th modes are relatively sensitive. For different parts, the contributions of vibration modes on the vibration response are different. For the part far from the roof ridge, only considering the first 5th modes can reflect the wind-induced vibration response. For the part near the ridge, at least the first 12 modes should be considered, due to complex vibration response. The wind vibration coefficients of the upwind side are slightly higher than that of the leeward side. Finally, the corresponding wind vibration coefficient for the purlin-sheet roof is proposed.

Numerical parametric analysis on the ultimate bearing capacity of the purlin-sheet roofs connected by standing seam clips

Yingying Zhang,Xiaoguang Song,Qilin Zhang 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.63 No.2

This paper presents the parametric numerical analysis on the ultimate bearing capacity of the purlin-sheet roofs connected by standing seam clips. The effects of several factors on failure modes and ultimate bearing capacity of the purlins are studied, including setup of anti-sag bar, purlin type, sheet thickness and connection type et al. A simplified design formula is proposed for predicting the ultimate bearing capacity of purlins. Results show that setting the anti-sag bars can improve the ultimate bearing capacity and change the failure modes of C purlins significantly. The failure modes and ultimate bearing capacity of C purlins are significantly different from those of Z purlins, in the purlin-sheet roof connected by standing seam clips. Setting the anti-sag bars near the lower flange is more favorable for increasing the ultimate bearing capacity of purlins. The ultimate bearing capacity of C purlins increases slightly with sheet thickness increasing from 0.6 mm to 0.8 mm. The ultimate bearing capacity of the purlin-sheet roofs connected by standing seam clips is always higher than those by self-drilling screws. The predictions of the proposed design formulas are relatively in good agreement with those of EN 1993-1-3: 2006, compared with GB 50018-2002.

Population-Stratified Analysis of Bone Mineral Density Distribution in Cervical and Lumbar Vertebrae of Chinese from Quantitative Computed Tomography

Yong Zhang,Zhuang Zhou,Cheng’ai Wu,Danhui Zhao,Chao Wang,Xiaoguang Cheng,Wei Cai,Ling Wang,Yangyang Duanmu,Chenxin Zhang,Wei Tian 대한영상의학회 2016 Korean Journal of Radiology Vol.17 No.5

Objective: To investigate the bone mineral density (BMD) of cervical vertebrae in a population-stratified manner and correlate with that of the lumbar vertebrae. Materials and Methods: Five hundred and ninety-eight healthy volunteers (254 males, 344 females), ranging from 20 to 64 years of age, were recruited for volumetric BMD (vBMD) measurements by quantitative computed tomography. Basic information (age, height, weight, waistline, and hipline), and vBMD of the cervical and lumbar vertebrae (C2–7 and L2–4) were recorded. Comparisons among sex, age groups and different levels of vertebrae were analyzed using analysis of variance. Linear regression was performed for relevance of different vertebral levels. Results: The vBMD of cervical and lumbar vertebrae was higher in females than males in each age group. The vBMD of the cervical and lumbar vertebrae in males and the vBMD of lumbar vertebrae in females decreased with aging. In each age group, the vBMD of the cervical vertebrae was higher than that of the lumbar vertebrae with gradual decreases from C2 to C7 except for C3; moreover, the vBMD of C6 and C7 was significantly different from that of C2–5. Correlations of vBMD among different cervical vertebrae (females: r = 0.62–0.94; males: r = 0.63–0.94) and lumbar vertebrae (males: r = 0.93–0.98; females: r = 0.82–0.97) were statistically significant at each age group. Conclusion: The present study provided normative data of cervical vertebrae in an age- and sex-stratified manner. Sex differences in vBMD prominently vary with age, which can be helpful to design a more comprehensive pre-operative surgical plan.