Simulation of Unsteady Incompressible 2D Cylinder Flow with Physics-Informed Neural Network

Hui Xiang,Yanbo Zhang,Yuanye Zhou,Tianyuan Liu,Xin Xie,Yunzhu Li,Qiao Zhao 한국전산유체공학회 2022 한국전산유체공학회 학술대회논문집 Vol.2022 No.10

Design of a TRIAC Dimmable LED Driver Chip with a Wide Tuning Range and Two-Stage Uniform Dimming

Changyuan Chang,Zhen Li,Yuanye Li,Chao Hong 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.2

A TRIAC dimmable LED driver with a wide tuning range and a two-stage uniform dimming scheme is proposed in this paper. To solve the restricted dimming range problem caused by the limited conduction ratio of TRIAC dimmers, a conduction ratio compensation technique is introduced, which can increase the output current up to the rated output current when the TRIAC dimmer turns to the maximum conduction ratio. For further optimization, a two-stage uniform dimming diagram with a rapid dimming curve and a slow dimming curve is designed to make the LED driver regulated visually uniform in the whole adjustable range of the TRIAC dimmer. The proposed control chip is fabricated in a TSMC 0.35μm 5V/650V CMOS/LDMOS process, and verified on a 21V/500mA circuit prototype. The test results show that, in the 90V/60Hz~132V/60Hz ac input range, the voltage linear regulation is 2.6%, the power factor is 99.5% and the efficiency is 83%. Moreover, in the dimming mode, the dimming rate is less than 1% when the maximum dimming current is 516mA and the minimum dimming current is only about 5mA.

Analysis and Design of a Separate Sampling Adaptive PID Algorithm for Digital DC-DC Converters

Chang, Changyuan,Zhao, Xin,Xu, Chunxue,Li, Yuanye,Wu, Cheng'en The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.6

Based on the conventional PID algorithm and the adaptive PID (AD-PID) algorithm, a separate sampling adaptive PID (SSA-PID) algorithm is proposed to improve the transient response of digitally controlled DC-DC converters. The SSA-PID algorithm, which can be divided into an oversampled adaptive P (AD-P) control and an adaptive ID (AD-ID) control, adopts a higher sampling frequency for AD-P control and a conventional sampling frequency for AD-ID control. In addition, it can also adaptively adjust the PID parameters (i.e. $K_p$, $K_i$ and $K_d$) based on the system state. Simulation results show that the proposed algorithm has better line transient and load transient responses than the conventional PID and AD-PID algorithms. Compared with the conventional PID and AD-PID algorithms, the experimental results based on a FPGA indicate that the recovery time of the SSA-PID algorithm is reduced by 80% and 67% separately, and that overshoot is decreased by 33% and 12% for a 700mA load step. Moreover, the SSA-PID algorithm can achieve zero overshoot during startup.

Design of a TRIAC Dimmable LED Driver Chip with a Wide Tuning Range and Two-Stage Uniform Dimming

Chang, Changyuan,Li, Zhen,Li, Yuanye,Hong, Chao The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.2

A TRIAC dimmable LED driver with a wide tuning range and a two-stage uniform dimming scheme is proposed in this paper. To solve the restricted dimming range problem caused by the limited conduction ratio of TRIAC dimmers, a conduction ratio compensation technique is introduced, which can increase the output current up to the rated output current when the TRIAC dimmer turns to the maximum conduction ratio. For further optimization, a two-stage uniform dimming diagram with a rapid dimming curve and a slow dimming curve is designed to make the LED driver regulated visually uniform in the whole adjustable range of the TRIAC dimmer. The proposed control chip is fabricated in a TSMC $0.35{\mu}m$ 5V/650V CMOS/LDMOS process, and verified on a 21V/500mA circuit prototype. The test results show that, in the 90V/60Hz~132V/60Hz ac input range, the voltage linear regulation is 2.6%, the power factor is 99.5% and the efficiency is 83%. Moreover, in the dimming mode, the dimming rate is less than 1% when the maximum dimming current is 516mA and the minimum dimming current is only about 5mA.

Analysis and Design of a Separate Sampling Adaptive PID Algorithm for Digital DC-DC Converters

Changyuan Chang,Xin Zhao,Chunxue Xu,Yuanye Li,Cheng`en Wu 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.6

Based on the conventional PID algorithm and the adaptive PID (AD-PID) algorithm, a separate sampling adaptive PID (SSA-PID) algorithm is proposed to improve the transient response of digitally controlled DC-DC converters. The SSA-PID algorithm, which can be divided into an oversampled adaptive P (AD-P) control and an adaptive ID (AD-ID) control, adopts a higher sampling frequency for AD-P control and a conventional sampling frequency for AD-ID control. In addition, it can also adaptively adjust the PID parameters (i.e. Kp, Ki and Kd) based on the system state. Simulation results show that the proposed algorithm has better line transient and load transient responses than the conventional PID and AD-PID algorithms. Compared with the conventional PID and AD-PID algorithms, the experimental results based on a FPGA indicate that the recovery time of the SSA-PID algorithm is reduced by 80% and 67% separately, and that overshoot is decreased by 33% and 12% for a 700㎃ load step. Moreover, the SSA-PID algorithm can achieve zero overshoot during startup.

A Three-dimension Huge Data Extraction Algorithm for Visualization Based on Computational Meshes

Yuan Ye,Tian Zhongxu 보안공학연구지원센터 2015 International Journal of Database Theory and Appli Vol.8 No.3

In order to accelerate the visualization processes of huge engineering data based on computational meshes, the extraction of huge data are necessary. A data extraction algorithm of engineering visualization data based on meshes is presented. Based on ordinary four-node tetrahedron elements, ten -node tetrahedron elements, eight-node hexahedron elements, the algorithms are studied to extract and simplify data for huge engineering data visualization, which includes relationships judgment between objective points and elements and interpolation algorithm in elements. Experiments of huge data transportation are given here, which show that the algorithm is reliable, and the algorithm can be used to extract visualization data from huge data of engineering computational results.

A New Keystone Correction Algorithm Based on Edge-directed Interpolation of The Projector

Yuan Ye 보안공학연구지원센터 2015 International Journal of Signal Processing, Image Vol.8 No.6

A trapezoid is generated in screen when the projector is not perpendicular to the screen body in most situations. It is called the keystone distortion. In order to solve the keystone distortion of images, a new algorithm transforming pixel spatial position using edge preserving interpolation is proposed to implement projector keystone correction. First, the scaling factors, the start point positions and the end point positions are calculated according to different rows, then the edge preserving interpolation algorithm are used according to the space positions. Experimental results demonstrate that the algorithm can not only implement keystone correction, but also preserves the edge effectively. This algorithm can be used in the chip of projector video processing to solve the keystone distortion.

Mathematical Modeling and Control for A Single Winding Bearingless Flywheel Motor in Electric/Suspension Mode

Yuan Ye,Huang Yonghong,Xiang Qianwen,Sun Yukun 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.5

With the increase of the production of energy from renewable, it becomes important to look at techniques to store this energy. Therefore, a single winding bearingless flywheel motor (SWBFM) specially for flywheel energy storage system is introduced. For the control system of SWBFM, coupling between the torque and the suspension subsystems exists inevitably. It is necessary to build a reasonable radial force mathematical model to precisely control SWBFM. However, SWBFM has twelve independently controlled windings which leads to high-order matrix transformation and complex differential calculation in the process of mathematical modeling based on virtual displacement method. In this frame, a Maxwell tensor modeling method which is no need the detailed derivation and complex theoretical computation is present. Moreover, it possesses advantages of universality, accuracy, and directness. The fringing magnetic path is improved from straight and circular lines to elliptical line and the rationality of elliptical line is verified by virtual displacement theory according to electromagnetic torque characteristics. A correction function is taken to increase the model accuracy based on finite element analysis. Simulation and experimental results show that the control system of SWBFM with radial force mathematical model based on Maxwell tensor method is feasible and has high precision.