ZSCC suppression method for parallel three‑level inverters based on model predictive control with virtual location vector

Ling Mao,Yuankai Li,Chao Pan,Jianlin Yang,Qin Hu,Yuncong Zheng,Jinbin Zhao 전력전자학회 2024 JOURNAL OF POWER ELECTRONICS Vol.24 No.4

Parallel three-level neutral point clamped (3L-NPC) inverters are widely used in power conversion applications, such as new energy generation and high voltage inverters. However, the zero-sequence circulating current (ZSCC) between two inverters degrades the whole performance of the system. To suppress the ZSCC in parallel inverters and improve the quality of output current, this study proposes an MPC strategy based on the virtual location vector. First, to reduce the computational burden of MPC, the virtual location vector is constructed by the output current of two inverters so that the control of the parallel inverters is similar to that of a single inverter. Then, the virtual location vector is obtained by using the direct power control method. Finally, the sets of candidate voltage vectors for MPC are determined on the basis of this reference voltage vector and the magnitude of ZSCC. Moreover, the optimal vectors calculated by MPC are assigned to the two inverters. Compared with the traditional MPC strategy, the MPC strategy proposed in this study has better steady state and transient performance with less computational burden. The proposed method is validated in simulation and experimental platforms.

Fault Detection for a Class of Nonlinear Networked Control Systems with Communication Constraints

Zehui Mao,Yifei Pan,Bin Jiang,Wen Chen 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.1

This paper is concerned with fault detection for a class of nonlinear networked control systems with stochastic transfer delays and data drops. A modified T-S fuzzy model is used to represent the considered system. The infinitely distributed time delays are introduced to describe the delays in the controllers. In the fault detection filter, a sequence of stochastic variables is introduced to govern the random occurrence of the stochastic transfer delays and data drops in the measurements, and all of the stochastic variables are mutually independent. Sufficient conditions using regular and piecewise Lyapunov functions are derived for the existence of the designed filter. An example is employed to show the effectiveness and applicability of the proposed fault-detection method.

Taint Inference for Cross-Site Scripting in Context of URL Rewriting and HTML Sanitization

Jinkun Pan,Xiaoguang Mao,Weishi Li 한국전자통신연구원 2016 ETRI Journal Vol.38 No.2

Currently, web applications are gaining in prevalence. In a web application, an input may not be appropriately validated, making the web application susceptible to cross-site scripting (XSS), which poses serious security problems for Internet users and websites to whom such trusted web pages belong. A taint inference is a type of information flow analysis technique that is useful in detecting XSS on the client side. However, in existing techniques, two current practical issues have yet to be handled properly. One is URL rewriting, which transforms a standard URL into a clearer and more manageable form. Another is HTML sanitization, which filters an input against blacklists or whitelists of HTML tags or attributes. In this paper, we make an analogy between the taint inference problem and the molecule sequence alignment problem in bioinformatics, and transfer two techniques related to the latter over to the former to solve the aforementioned yet-to-be-handled-properly practical issues. In particular, in our method, URL rewriting is addressed using local sequence alignment and HTML sanitization is modeled by introducing a removal gap penalty. Empirical results demonstrate the effectiveness and efficiency of our method.

A Preliminary Simulation on the Radiance Imagery of Ocean Color Sensor OSMI

Delu Pan,김용승,Tianming Mao 한국항공우주학회 1999 한국항공우주학회 학술발표회 논문집 Vol.- No.-

A novel fiber Bragg grating sensing interrogation system using bidirectional modulation of Mach-Zehnder electro-optical modulator

Wankai Mao,Jae Kyung Pan 한국통신학회 2009 한국통신학회 기타 간행물 Vol.2009 No.12

A Novel Fiber Bragg Grating Sensing Interrogation Method Using Bidirectional Modulation of a Mach-Zehnder Electro-Optical Modulator

모만개,반재경,Mao, Wankai,Pan, Jae-Kyung The Institute of Electronics and Information Engin 2010 電子工學會論文誌-CI (Computer and Information) Vol.47 No.7

본 논문에서는 Mach-Zehnder 광변조기의 양방향 변조를 이용하는 새로운 광섬유격자 센서 검출 방법을 제안하고 실험을 통하여 그 유용성을 밝힌다. 제안한 구조는 광대역 광원, 광섬유격자, Mach-Zehnder 광변조기, chirped 광섬유격자, 그리고 광 검출기로 구성된다. 실험을 통하여 제안한 구조의 전달함수를 구하고, 505 MHz에서 525 MHz까지 주파수 영역에서 10개의 다른 파장을 가진 광에 대한 FSR(free spectral range)의 변화로부터 시간지연을 계산한다. 구한 결과로부터 광의 파장 변화에 따른 시간지연이 12.9 ps/0.2 nm 값을 가지면서 매우 선형적임을 알 수 있다. 이러한 결과는 광섬유격자를 이용한 스트레인 또는 온도 센서에 이용할 수 있다. We have proposed and experimentally demonstrated a novel fiber Bragg grating (FBG) sensing interrogation method using bidirectional modulation of a Mach-Zehnder electro-optical modulator (MZ-EOM). The proposed structure consists mainly of a broadband light source (BBS), FBG, MZ-EOM, chirped fiber Bragg grating (CFBG), and photodetector (PD). We have obtained the transfer functions of the proposed structure and calculated the time delay from the change in the free spectral range (FSR) for ten wavelengths over the frequency range of 505 MHz to 525 MHz. The results show that the time delay and the wavelength variation have a good linear relationship with a gradient of 12.9 ps/0.2 nm, which can be usefully applied to FBG strain or temperature sensors and other multiplexed sensor applications.

A putative pathogen-resistant regulatory pathway between MicroRNAs and candidate target genes in maize

Jian Gao,Mao Luo,Chun Zhang,Hua Peng,Haijian Lin,Yaou shen,Maojun Zhao,Guangtang Pan,Zhiming Zhang 한국식물학회 2015 Journal of Plant Biology Vol.58 No.4

MicroRNAs (miRNAs) are a family of small non-coding RNAs that, in most cases, negatively regulate gene expression at the post-transcriptional level. Plant miRNAs have been implicated in developmental processes and adaptation to environmental stress including biotic and abiotic stresses. Here, we report a comprehensive analysis of miRNAs and associated target genes under banded leaf and sheath blight (BLSB) stress caused by R. solani in maize. Eight differentially expressed miRNAs were randomly selected from deep sequencing results and validated by qRT-PCR together with their putative target genes, most of which are transcription factors as well as metabolic genes involved in auxin signaling. The results revealed that majorities of the analyzed miRNAs show an inverse correlation with their corresponding predicted target genes. In addition, a putative regulatory network of miRNAs-mRNAs responsive to R. solani was constructed. This study provides insight into the regulatory functions of miRNAs, thereby expanding our knowledge of the molecular mechanisms of pathogen resistance.

A Novel Fiber Bragg Grating Sensing Interrogation Method Using Bidirectional Modulation of a Mach-Zehnder Electro-Optical Modulator

모만개(Wankai Mao),반재경(Jae-Kyung Pan) 대한전자공학회 2010 電子工學會論文誌-SD (Semiconductor and devices) Vol.47 No.7

본 논문에서는 Mach-Zehnder 광변조기의 양방향 변조를 이용하는 새로운 광섬유격자 센서 검출 방법을 제안하고 실험을 통하여 그 유용성을 밝힌다. 제안한 구조는 광대역 광원, 광섬유격자, Mach-Zehnder 광변조기, chirped 광섬유격자, 그리고 광 검출기로 구성된다. 실험을 통하여 제안한 구조의 전달함수를 구하고, 505 ㎒에서 525 ㎒까지 주파수 영역에서 10개의 다른 파장을 가진 광에 대한 FSR(free spectral range)의 변화로부터 시간지연을 계산한다. 구한 결과로부터 광의 파장 변화에 따른 시간지연이 12.9 ps/0.2 ㎚ 값을 가지면서 매우 선형적임을 알 수 있다. 이러한 결과는 광섬유격자를 이용한 스트레인 또는 온도 센서에 이용할 수 있다. We have proposed and experimentally demonstrated a novel fiber Bragg grating (FBG) sensing interrogation method using bidirectional modulation of a Mach-Zehnder electro-optical modulator (MZ-EOM). The proposed structure consists mainly of a broadband light source (BBS), FBG, MZ-EOM, chirped fiber Bragg grating (CFBG), and photodetector (PD). We have obtained the transfer functions of the proposed structure and calculated the time delay from the change in the free spectral range (FSR) for ten wavelengths over the frequency range of 505 ㎒ to 525 ㎒. The results show that the time delay and the wavelength variation have a good linear relationship with a gradient of 12.9 ps/0.2 ㎚, which can be usefully applied to FBG strain or temperature sensors and other multiplexed sensor applications.

A Nanofilter Array Chip for Fast Gel-Free Biomolecule Separation.

Fu, Jianping,Mao, Pan,Han, Jongyoon American Institute of Physics 2005 APPLIED PHYSICS LETTERS Vol.87 No.26

<P>We report here a microfabricated nanofilter array chip that can size-fractionate SDS-protein complexes and small DNA molecules based on the Ogston sieving mechanism. Nanofilter arrays with a gap size of 40-180nm were fabricated and characterized. Complete separation of SDS-protein complexes and small DNA molecules were achieved in several minutes with a separation length of 5mm. The fabrication strategy for the nanofilter array chip allows further increasing of the nanofilter density and decreasing of the nanofilter gap size, leading, in principle, to even faster separation.</P>

Modeling and simulating of center plate torsion behavior during bogie curve and turnout negotiation

Wang Shibo,Mao Yong,Teng Bing,Pan Li 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.7

In order to accurately simulating the tribological behavior of center plate of bogie, a model was built to calculate the torsional kinematicsparameters of the center plate when a railway freight-car bogie passes through a curve and a railway turnout. According to the torsionalkinematics parameters, a plate-on-plate torsional friction tester was built. The variation of the torsional angle, angular speed, andangular acceleration of the center plate under different conditions was investigated. The torsional angle was affected by the distancesbetween bogie centers and the radius of the railway circular curve. For different railway track geometries, the torsional angle of the centerplate during bogie curve and turnout negotiation ranged within 0.016°-1.08° and 0.04°-1.96°, respectively. The torsional speed of thecenter plate under the turnout condition was much higher than that under the curve condition. The torsional friction behavior of a centerplate material was simulated with the tester according to the calculated results.