Liu Hua

Chongqing Jiaotong University

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i-10 index

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Quanxin Ding

AVIC Optronics (China)

Yuguo Wang

Northwest A&F University

Liwei Zhou

Peking University

Hong Zhang

Anhui Science and Technology University

Shiyu Yan

National Health and Family Planning Commission

Baoqun Zhao

Hebei University of Engineering

Chengwen Wang

Anhui Polytechnic University

Aili Qin

Hebei University of Engineering

Jian Hua Tao

Tianjin University

Shen Song-hua

Beihang University

Cooperative Institutions

Tianjin Agricultural University

Chinese Academy of Sciences

University of South China

Xi'an Jiaotong University

Peking University

Shanghai Jiao Tong University

South China University of Technology

Chongqing University

Dalian University of Technology

Tsinghua University

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Fluorescence quantum efficiency and branch ratio of ytterbium ion in glasses

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE (2000)

Chun Jiang Liu Hua Qingji Zeng Xiaodong Tang Junzhou Zhang

In this paper the fluorescence quantum efficiencies and branch ratios of ytterbium doped oxide glasses are firstly calculated with equation derived from the reciprocity principle. It is shown that using absorption spectra of ytterbium doped glasses including borate, phosphate, niobosilicate, telluorogermanate and tellurite glasses, the fluorescence quantum efficiencies are obtained and varies from 80% to 99%, increasing with decreasing phonon energy of glass hosts. The branch ratios change slightly as glass hosts with different phonon energy and are about 40%, 30%, 30%, 0% around 970 nm, 1000 nm, 1020 nm, 1050 nm wavelength, respectively.

Ytterbium

Phosphate glass

Quantum yield

10.1117/12.382874

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Citations (2)

On advanced configuration enhance adaptive system optimization

Quanxin Ding Hongliang Chen Liu Hua Helong Wang Chunjie Guo

For aim to find an effective method to structure to enhance these adaptive system with some complex function and look forward to establish an universally applicable solution in prototype and optimization. As the most attractive component in adaptive system, wave front corrector is constrained by some conventional technique and components, such as polarization dependence and narrow working waveband. Advanced configuration based on a polarized beam split can optimized energy splitting method used to overcome these problems effective. With the global algorithm, the bandwidth has been amplified by more than five times as compared with that of traditional ones. Simulation results show that the system can meet the application requirements in MTF and other related criteria. Compared with the conventional design, the system has reduced in volume and weight significantly. Therefore, the determining factors are the prototype selection and the system configuration, Results show their effectiveness.

Adaptive system

Component (thermodynamics)

10.1117/12.2285737

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Citations (0)

Nonlinear predictive control for active power filter

Xiaogang Wang Liu Hua Zhang Jie

A nonlinear optimal predictive controller for current control of paralleled three-phase three-leg active power filter is presented. The objective is to track distorted currents with sudden changes. In order to achieve robustness to parameter uncertainties, a disturbance observer is introduced. The deduced control law has closed analytical form and on-line dynamic optimization is omitted and easy to implement. The simulation results show that the APF based on the proposed control law has good performance, as well as strong robustness.

Robustness

Model Predictive Control

Active power filter

10.1109/appeec.2013.6837201

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Citations (1)

Analytical investigation of torque and flux ripple in induction motor control scheme using wavelet network

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE (2008)

Liu Hua Hong Zhang Aili Qin

An effective scheme of parameter identification based on wavelet neural network is presented for improving dynamic performance of direct torque control system. The wavelet transform is localized in time-frequency domains, yielding wavelet coefficients at different scales. This gives the wavelet transform much greater compact support for analysis of signals with localized transient components. The input nodes of wavelet neural network are current error and change in the current error and the output node is the stator resistance error. To fulfill the network structure parameter, the improved least squares algorithm is used for initialization. The stator flux vector and electromagnetic torque are acquired accurately by the parameter estimator once the instants are detected. This function can make induction motor operate well in low region and can optimize the inverter control strategy. The simulation results show that the proposed method can efficiently reduce the torque ripple and current ripple.

Torque ripple

Initialization

10.1117/12.807381

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Citations (0)

Garment Handling and Corresponding Devices-Technology in Robotic Ironing

Journal of Mechanical Engineering (2005)

Jian S. Dai P. Liu Liu Hua

Source

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Citations (1)

Performance improvement of direct torque control system based on dynamic parameter identification technology

Chinese Control and Decision Conference (2009)

Liu Hua Zhao Wei Zhanfeng Li

In traditional direct torque control system, the torque and flux are directly controlled by means of optimum voltage vectors, where the stator resistance variation deteriorates the dynamic performance. It is necessary to improve estimation accuracy for stator flux and torque. Considering the effects of the stator resistance variation on direct torque control, a novel approach of stator resistance identification based on wavelet network is presented for dynamic performance in low speed status, optimizing the inverter control strategy. The wavelet transform decomposes the signal using dilated and translated wavelets in time-frequency domain into a series of correlation factors or wavelet coefficients. The wavelet network combines the mathematical feature of wavelet transform with learning scheme of conventional neural network into an organic unit, which has been applied to nonlinear function approximation and dynamical system modeling. The improved training algorithm is utilized to fulfill the network parameter initialization, increasing the network stabilization and convergence property. Therefore, the stator voltage vector can be obtained from the stator resistance identification result of wavelet network output, reducing the number of voltage sensors. The simulation results show that the steady state and dynamic performance was improved.

Initialization

10.1109/ccdc.2009.5192622

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Citations (0)

Device of a Multi-functional Baby Cradle

Advances in intelligent systems and computing (2020)

Hongli Men Liu Hua Лей Ма

10.1007/978-3-030-43306-2_41

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Citations (0)

Time frequency distribution for vibration signal analysis with application to turbo-generator fault diagnosis

Chinese Control and Decision Conference (2009)

Liu Hua Zhanfeng Li Zhaowei

With the growing demand for improving reliability and performance of turbo-generator set as an important power supply in modern electric industry, the vibration signal processing and fault diagnosis techniques have been developed for dynamic feature extraction and pattern recognition. A new approach using wavelet transform and fuzzy network modeling is presented for vibration fault diagnosis of turbo-generator set. The wavelet transform decomposes the vibration signal in time domain into a two-dimensional function in time-scale plane, which analyzes the low-frequency component of signal with a wide duration function and analyzes conversely high-frequency component with short-duration function. The wavelet fuzzy method can generate dilation and translation parameters, and the network output vector is a linear combination of fuzzy wavelet basis functions. The approximation procedure can achieve better approximation of accuracy order than normal neural network and fuzzy system. The experiment results and analysis approve that the proposed approach is effective, improving the accuracy and reliability of fault diagnosis technology for rotating machinery vibration.

Turbo generator

10.1109/ccdc.2009.5191783

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Citations (6)

Extended-state-observer based sliding mode control for pump-controlled electro-hydraulic servo system

Beijing Hangkong Hangtian Daxue xuebao (2020)

Xinping Guo Chengwen Wang Liu Hua Zhenyang Zhang Xinhao Ji

Observer (physics)

Servomechanism

Mode (computer interface)

10.13700/j.bh.1001-5965.2019.0418

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