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Annual Conference of the IEEE Industrial Electronics Society

作者： Amer M. Y. M. Ghias Josep Pou Vassilios G. Agelidis Mihai Ciobotaru Australian Energy Research Institute & School of Electrical Engineering and Telecommunications The University of New South Wales

ISBN: (纸本)9781479902255

This paper proposes an active voltage balancing method for stacked multicell converters (SMC) using phase-shifted pulse-width modulation, which is easy to implement and extend to high number of levels. The proposed method balances the voltages of the capacitors by modifying the duty cycle of each switch of the SMC using a proportional controller. The crossed effect between capacitor currents and duty cycles is considered and is used for optimal capacitor voltage balance. The performance of the proposed voltage balancing method is verified by simulation for different operating conditions, such as unbalanced linear loads, non-linear loads and load transients.

关键词： Multilevel converter Stacked multicell converter Capacitor voltage balancing pulse-width modulation voltage balance multistage converter phase shifted pulse width modulation pulse width modulation SELECTION AND MONITORING CHASSIS Sheet molding compounds Small Magellanic Cloud DUTY CYCLE multicell Capacitors Converters

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Motor Performance Investigation of an Indirect Matrix Converter with a Reactor-Free Boost Converter

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IEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING 2012年第4期7卷 429-435页

作者： Chiang, Goh Teck Itoh, Jun-ichi Nagaoka Univ Technol Power Elect Lab Nagaoka Niigata 9402188 Japan

This paper describes a three-phase power converter which utilizes the neutral point of an induction motor and demonstrates the performance of the motor using the proposed method under various operating conditions. Several motor test results, such as the speed-torque characteristic, the torque impact, and the acceleration-deceleration characteristic, are included to confirm the performance of the induction motor. The structure of the proposed circuit consists primarily of an AC/AC converter [indirect matrix converter (IMC)] and a boost converter connected to the neutral point of the induction motor. In addition, this paper also proposes a method to reduce the ripple found in the battery current. Several experimental results show that the motor works well, and even the leakage inductance is utilized in the boost converter. (c) 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

关键词： indirect matrix converter boost converter induction motor neutral point of the motor pulse-width modulation

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pulse COMPRESSION AND PEDESTAL SUPPRESSION FOR THE HIGH-ORDER SOLITONS

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JOURNAL OF ELECTROMAGNETIC WAVES AND APPLICATIONS 2012年第8-9期26卷 1261-1273页

作者： Liu, W. -J. Tian, B. Li, M. Wang, P. Jiang, Y. Beijing Univ Posts & Telecommun State Key Lab Informat Photon & Opt Commun Beijing 100876 Peoples R China Beijing Univ Posts & Telecommun Sch Sci Beijing 100876 Peoples R China

A pulse compression and pedestal suppression method for high-order solitons is presented in this paper. With the existing analytic solutions, the second- and third-order solitons are compressed, and the optimum lengths for them are obtained. Without the soliton broadening, the pedestals of the solitons from different outputs can be suppressed with the choices of corresponding parameters. Unlike other pedestal suppression methods, the energy of the pedestal is transferred to the peak of the soliton, and the output intensity of the high-order compressed solitons increases during the pedestal suppression. As the soliton order increases, results show that the optimum length for the pedestal suppression increases, and the pulse width decreases.

关键词： pulse-width modulation SOLITONS OPTICAL communications ENERGY transfer QUANTUM theory INFORMATION theory

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Continuous time Δ Σ modulation with PWM pre-coding and binary g_m blocks

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ELECTRONICS LETTERS 2012年第19期48卷 1187-U33页

作者： Fishani, A. Babaie Rombouts, P. Univ Ghent ELIS CAS B-9000 Ghent Belgium

A very simple technique to implement the first integrator of a continuous-time delta sigma modulator (CT-DSM) is presented. In the approach, the CT-DSM is preceded by a pulse-width modulator to convert the input signal to a pseudo-digital continuous time waveform. As a result, the first integrator of the DSM can be implemented with a capacitor and a switched current source, with inherent linearity. To illustrate the concept, it has been applied to the design of a second-order CT-DSM in 65 nm CMOS technology.

关键词： Continuous time systems Integrators Delta modulation pulse-width modulation Signal-to-noise ratio Switched capacitor filters Switching power supplies Pseudodifferential operators

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330 MHz, sub 50 fs Yb: Fiber ring laser

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OPTICS COMMUNICATIONS 2012年第9期285卷 2430-2432页

作者： Li, Peng Wang, Aimin Wang, Xi Zhang, Zhigang Peking Univ Inst Quantum Elect State Key Lab Adv Opt Commun Syst & Networks Sch Elect Engn & Comp Sci Beijing 100871 Peoples R China

We demonstrate 330 MHz repetition rate operation in a ring cavity Yb:fiber laser with an innovative wavelength-division-multiplexing collimator to raise the repetition rate. The spectral bandwidth of the pulse is 30 nm and the dechirped pulse width is 48 fs. The output power is 70 mW with 600 mW, 975 nm pump laser diode. (C) 2012 Elsevier B.V. All rights reserved.

关键词： FIBER lasers YTTERBIUM WAVELENGTH division multiplexing COLLIMATORS (Optical instrument) SPECTRUM analysis BANDwidthS pulse-width modulation DIODES OPTICAL pumping

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High-energy Ho:LLF MOPA laser system using a top-hat pump profile for the amplifier stage

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APPLIED PHYSICS B-LASERS AND OPTICS 2012年第2期109卷 351-357页

作者： Schellhorn, Martin Eichhorn, Marc French German Res Inst St Louis ISL F-68301 St Louis France

Numerical simulations show the advantage of using a top-hat intensity profile pumping the amplifier stage in an Ho:LuLiF4 (Ho:LLF) master oscillator power amplifier (MOPA) configuration over a Gaussian pump profile: higher pulse energies could be generated simultaneously with reduced peak fluence in Q-switched operation. In the experimental implementation, the top-hat beam was realized with a coherent beam transformation of the non-absorbed pump beam transmitted by the oscillator to pump the amplifier stage. The Ho:LLF MOPA produced 103.6 mJ at a repetition rate of 100 Hz with a pulse duration of 30 ns at a wavelength of 2053 nm, which corresponds to an optical-to-optical efficiency of 12.9 %. The beam quality was nearly diffraction limited (M (2) = 1.03).

关键词： POWER amplifiers LASER beams COMPUTER simulation pulse-width modulation OPTICAL pumping GAUSSIAN beams COHERENCE (Optics) OPTICAL diffraction

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Simplified detection of broken rotor bars in induction motors controlled in field reference frame

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CONTROL ENGINEERING PRACTICE 2012年第8期20卷 761-769页

作者： Drobnic, Klemen Nemec, Mitja Fiser, Rastko Ambrozic, Vanja Univ Ljubljana Fac Elect Engn Ljubljana 1000 Slovenia

In this paper, a simple method for additional on-line detection of broken rotor bars in a squirrel cage induction motor controlled in rotor field co-ordinates using existing hardware is presented. Based on a previously presented approach, an algorithm for on-line calculation of the variance of stator voltage reference, which depends on the number of broken bars, has been developed. Due to its simplicity, it could run in parallel with a standard control algorithm in field reference frame using contemporary fixed- and floating-point processors, thus requiring minimum processing time. The algorithm uses internal reference values of the stator voltage: therefore no additional dedicated measurements are needed. Results were obtained at different operating points on an induction motor with gradually damaged rotor. Comparison with commonly used diagnostic method confirms the validity of the approach. (C) 2012 Elsevier Ltd. All rights reserved.

关键词： Fault diagnosis Induction motors pulse-width modulation Microprocessors Motor control

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Three-dimensional simulations of an induction motor including eddy current effects in core laminations

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IET SCIENCE MEASUREMENT & TECHNOLOGY 2012年第5期6卷 344-349页

作者： Jorks, H. V. Gjonaj, E. Weiland, T. Magdun, O. Tech Univ Darmstadt Inst Computat Electromagnet D-64289 Darmstadt Germany Tech Univ Darmstadt Inst Elect Energy Convers D-64283 Darmstadt Germany

This work is motivated by the investigation of the common mode ground current which occurs in induction machines controlled by pulse- width modulation (PWM) at higher frequencies. In order to quantify this current, the common mode impedance of the motor has to be determined. Using the transmission line approach the model parameters are extracted from both two-dimensional (2D) and three-dimensional (3D) field simulations. 2D finite-element (FE) analysis is an efficient tool for simulating the entire motor cross-section. However, eddy currents in the laminations cannot be modelled explicitly and have to be approximated by a semi-analytical formulation. The study investigates the accuracy of this model for a wide frequency range (10 Hz, . . . , 1 MHz). For this purpose, a specialised 3D simulation tool for induction motors was developed, taking into account the actual distribution of eddy currents in the laminations. Simulation results are presented for a simple one conductor test case as well as for an entire motor cross-section of an existing 240 kW motor.

关键词： three-dimensional simulations induction machines Finite element analysis motor cross-section 2D finite-element analysis pulse-width modulation pulse width modulation eddy currents core laminations higher frequencies eddy current effects induction motors induction motor common mode ground current Electric actuators and final control equipment common mode impedance transmission line approach Electromagnetic induction Asynchronous machines finite element analysis

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888 nm pumped 1342 nm Nd:YVO₄ oscillator Kerr-lens mode-locked using cascaded second-order nonlinearities

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APPLIED PHYSICS B-LASERS AND OPTICS 2012年第1期106卷 5-8页

作者： Lenhardt, F. Schaefer, C. Theobald, C. Nittmann, M. Bartschke, J. Knappe, R. L'huillier, J. A. Photon Zentrum Kaiserslautern eV D-67663 Kaiserslautern Germany Xiton Photon GmbH D-67663 Kaiserslautern Germany Lumera Laser GmbH D-67655 Kaiserslautern Germany

We report on a parametric Kerr-lens mode-locked 888 nm pumped Nd:YVO4 1342 nm oscillator using cascaded second-order nonlinearities in LBO. Stable ps-pulse-operation was achieved. For an output coupling of T=25% high average output power of 6.5 W, emitting Fourier-limited pulses with a duration of 10 ps was reached. By changing the output coupling to T=10%, we achieved much shorter pulses with a pulse duration of 4 ps for less lower average power of 4.8 W. The beam was diffraction limited with an M (2) parameter better than < 1.05.

关键词： OPTICAL pumping NONLINEAR optics OPTICAL parametric oscillators pulse-width modulation LASER beams NEODYMIUM

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Sub-nanosecond, 1-10 kHz, low-threshold, non-critical OPOs based on periodically poled KTP crystal pumped at 1,064 nm

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APPLIED PHYSICS B-LASERS AND OPTICS 2012年第2期109卷 211-214页

作者： Marchev, Georgi Dallocchio, Paolo Pirzio, Federico Agnesi, Antonio Reali, Giancarlo Petrov, Valentin Tyazhev, Aleksey Pasiskevicius, Valdas Thilmann, Nicky Laurell, Fredrik Ist Nazl Fis Nucl I-27100 Pavia Italy Univ Pavia Dipartimento Elettron I-27100 Pavia Italy Max Born Inst Nonlinear Opt & Ultrafast D-12489 Berlin Germany Royal Inst Technol Dept Appl Phys S-10691 Stockholm Sweden

We employed a 9-mm long periodically poled KTiOPO4 (PPKTP) crystal in an optical parametric oscillator (OPO) to generate sub-nanosecond idler pulses around 2.8 mu m. With a 1-cm long OPO cavity in a singly resonant configuration and double pass pumping by 1-ns pulses at 1,064 nm, the maximum idler energy reached 110 mu J at 1 kHz. Pumping with 500 ps pulses at 1-10 kHz, resulted in an idler energy of similar to 50 mu J and the shortest pulse duration of similar to 250 ps, ever reported for an OPO. The corresponding quantum conversion efficiencies were 32.5 and 34.9 %, respectively.

关键词： OPTICAL parametric oscillators OPTICAL pumping pulse-width modulation QUANTUM efficiency (Physics) ENERGY conversion LASER beams

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