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A Novel Resource Scheduling Scheme for CoMP Systems
( Wen`an Zhou ),( Jianlong Liu ),( Yiyu Zhang ),( Chengyi Yang ),( Xuhui Yang ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.2
Coordinated multiple points transmission and reception (CoMP) technology is used to mitigate the inter-cell interference, and increase cell average user normalized throughput and cell edge user normalized throughput. There are two kinds of radio resource schedule strategies in LTE-A/5G CoMP system, and they are called centralized scheduling strategy and distributed scheduling strategy. The regional centralized scheduling cannot solve interference of inter-region, and the distributed scheduling leads to worse efficiency in the utilize of resources. In this paper, a novel distributed scheduling scheme named 9-Cell alternate authorization (9-CAA) is proposed. In our scheme, time-domain resources are divided orthogonally by coloring theory for inter-region cooperation in 9-Cell scenario [6]. Then, we provide a formula based on 0-1 integer programming to get chromatic number in 9-CAA. Moreover, a feasible optimal chromatic number search algorithm named CNS-9CAA is proposed. In addition, this scheme is expanded to 3-Cell scenario, and name it 3-Cell alternate authorization (3-CAA). At last, simulation results indicate that 9/3-CAA scheme exceed All CU CoMP, 9/3C CU CoMP and DLC resource scheduling scheme in cell average user normalized throughput. Especially, compared with the non-CoMP scheme as a benchmark, the 9-CAA and 3-CAA have improved the edge user normalized throughput by 17.2% and 13.0% respectively.
A Thermal Model for Electrothermal Simulation of Power Modules
Meng, Jinlei,Wen, Xuhui,Zhong, Yulin,Qiu, Zhijie Journal of International Conference on Electrical 2013 Journal of international Conference on Electrical Vol.2 No.4
A thermal model of power modules based on the physical dimension and thermal properties is proposed in this paper. The heat path in the power module is considered as a one-dimensional heat transfer in the model. The method of the parameters extraction for the model is given in the paper. With high speed and accuracy, the thermal model is suit for electrothermal simulation. The proposed model is verified by experimental results.
Wenshan Li,Xuhui Wen,Jian Zhang,Youlong Wang 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.6
This paper describes a narrow pulse suppression method that is called hybrid modulation strategy for T-type neutral point clamped (TNPC) three-level converters. Conventional VSVPWM does not function well in high-frequency TNPC converters due to the problem of narrow pulses during the permanent magnet synchronous motor (PMSM) starting process. The narrow pulse phenomenon occurs when the ON/OFF state time of the driving pulse is less than the minimum time required by the power devices. The narrow pulse threatens the safe operation of power devices and results in a high surge voltage and electromagnetic interference. In addition, neutral point voltage unbalance is caused by the narrow pulse in motor starting process. The eff ects of the narrow pulse on the surge voltage and the neutral point voltage are both discussed in this paper. The minimum pulse width function is designed to defi ne the relationship between the gate drive signal and the modulation strategy. The switch pattern limited region of the virtual space vector modulation strategy is analyzed by the minimum pulse width function under both low and high modulation indexes. A resistance inductance load and a PMSM drive system test setup based on a TNPC three-level converter are both established to verify the analysis and eff ectiveness of the proposed method.
Practical SPICE Model for IGBT and PiN Diode Based on Finite Differential Method
Han Cao,Puqi Ning,Xuhui Wen,Tianshu Yuan 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.6
In this paper, a practical SPICE model for an IGBT and a PiN diode is proposed based on the Finite Differential Method (FDM). Other than the conventional Fourier model and the Hefner model, the excess carrier distribution can be accurately solved by a fast FDM in the SPICE simulation tool. In order to improve the accuracy of the SPICE model, the Taguchi method is adopted to calibrate the extracted parameters. This paper presents a numerical modelling approach of an IGBT and a PIN diode, which are also verified by SPICE simulations and experiments.
Practical SPICE Model for IGBT and PiN Diode Based on Finite Differential Method
Cao, Han,Ning, Puqi,Wen, Xuhui,Yuan, Tianshu The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.6
In this paper, a practical SPICE model for an IGBT and a PiN diode is proposed based on the Finite Differential Method (FDM). Other than the conventional Fourier model and the Hefner model, the excess carrier distribution can be accurately solved by a fast FDM in the SPICE simulation tool. In order to improve the accuracy of the SPICE model, the Taguchi method is adopted to calibrate the extracted parameters. This paper presents a numerical modelling approach of an IGBT and a PIN diode, which are also verified by SPICE simulations and experiments.
A Genetic Algorithm Based Motor Controller System Automatic Layout Method
Han Cao,Puqi Ning,Xuhui Wen,Tianshu Yuan 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5
In this paper, a genetic algorithm based automatic motor controller system layout design and optimization method is proposed for EV application. The modeling procedure including 3-D position and physical characteristic interpretation is described. The simplified purpose of optimization is to find a trade-off between volume and electrical performance of motor controller. Compared with the Pareto Front generated by enumeration method, the presented method can find the optimum solution with a higher speed. The proposed method can be easily extended to a complex system and can provide new approaches for motor controller system design.
Design Space Methodology and Its Application in Interior Permanent Magnet Motor Design
Fan, Tao,Li, Qi,Wen, Xuhui,Xu, Longya Journal of International Conference on Electrical 2012 Journal of international Conference on Electrical Vol.1 No.3
An innovative interpretation of the per-unit interior permanent magnet (IPM) machine model known as Design Space is presented in this paper. Based on the proposed Design Space formulation, an effective computation method to predict IPM machine performance factors, such as the current and power factor in a full range of speeds, is proposed. A systematic methodology is summarized, which translates the full speed range machine design procedure into the region determination on the so-called Design Space. The effect of dc-link voltage is also analyzed in a similar manner with the current and power factor. A series of IPM motors have been designed, and a preferred motor is selected with the help of the proposed Design Space Methodology (DSM), which has the best tradeoff between the nominal voltage and the dropped voltage condition. Experiment results show that the selected motor satisfies the machine requirements and all the design constrains, such as the current and back-EMF limitations.
Online monitoring of IGBT junction temperature based on V<sub>ce</sub> measurement
Cao, Han,Ning, Puqi,Chai, Xiaoguang,Zheng, Dan,Kang, Yuhui,Wen, Xuhui The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.2
In this paper, an online junction temperature monitoring method based on the on-state voltage under high collector current density measurements for IGBT power modules is proposed. Unlike the conventional junction temperature monitoring method, the presented method can extract the junction temperature during operation without altering the modulation strategy or topology of the converter. The proposed method is verified by simulations and the JEDEC-51 standard recommended approach. To accurately extract the on-state voltage during operation, a measurement circuit that combines the advantages of both the active MOSFET clamp and the diode clamp is designed and tested. It has been shown to have good accuracy and a rapid response time. After the calibration results are obtained, the presented method is applied to a three-phase voltage source converter controlled by a closed-loop SVPWM modulation strategy.
Li, Yang,Gao, Jing,Li, Qinliang,Peng, Mingfa,Sun, Xuhui,Li, Youyong,Yuan, Gang,Wen, Wen,Meyyappan, M. Royal Society of Chemistry 2011 Journal of materials chemistry Vol.21 No.19
<P>We report the preparation of α- and κ-phase In<SUB>2</SUB>Se<SUB>3</SUB> nanowires by thermal evaporation and investigation of their phase transformations <I>in situ</I> by synchrotron radiation X-ray diffraction (XRD) during a thermal annealing process. The κ-phase transformed into the α-phase at 500 °C and eventually transformed to high temperature α-phase with a layered structure of 5 atoms-5 atoms at 700 °C irreversibly. Different atomistic structures of In<SUB>2</SUB>Se<SUB>3</SUB> were modeled and optimized by DFT, which correlate well with the XRD results. The In<SUB>2</SUB>Se<SUB>3</SUB> nanowires also exhibit a large difference in resistivity before and after annealing.</P> <P>Graphic Abstract</P><P>In<SUB>2</SUB>Se<SUB>3</SUB> nanowires are synthesised by thermal evaporation and their phase transformations are investigated <I>in situ</I> by synchrotron radiation XRD. The nanowires also exhibit a large difference in resistivity before and after annealing. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c1jm10419e'> </P>