A software tool for learning the dynamic behavior of power electronics circuits

A new software tool for learning the dynamic behavior of power electronics circuits is developed for undergraduate students. This tool incorporates the merits of two well-known software packages, namely, the realistic time-domain simulation of PSpice and the parametric identification process of MatLab. Hence, without going through complicated mathematics, the students can easily obtain the transient response, transfer function, and frequency response of power electronics circuits. The software tool is exemplified using a buck dc-dc converter. Its accuracy is verified by comparing the simulation result with those obtained by the state-space averaging technique and the experimental measurement. © 1996 IEEE.published_or_final_versio

Electric vehicles

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Some observations and analyses of the 2011 Tohoku earthquake and tsunami

First, this article summarizes our field observations made along the coastlines of Miyagi and Iwate Prefectures in the Tohoku areas in 2012, including the cities of Ishinomaki, Onagawa, Minamisanriku, Kesennuma, Rikuzentakata, Ofunato, and Kamaishi. Some peculiar observations are reported, including the overturned buildings at Onagawa. Secondly, tsunami simulations were performed using COMCOT based on linear shallow water equations. The resolution of the bathymetry used is based on 1 min or 1.36 km grid downloadable from NOAA website. Three focal mechanism models proposed by United States Geological Survey (USGS), Chinese Academy of Science (CAS), and Tsukuba University (TU) were used to estimate the seismic moment, slip displacement on the fault plane, and fault rupture length and width by fitting empirical formulas. Tide gage readings were used to compare with these computer simulations. At far south inside the Tokyo Bay (Harumi station), all three USGS, CAS and TU based predictions are in phases with the actual tide gage readings, except that all models overestimate the water level by one to two times (from 1–2 m to 3–6 m). However, the tide gage predictions at Tateyama Mera station (southern tip of the Tokyo Bay and of Chiba Prefecture) are all out of phases from the observation. Further North, the recorded tide gage reading at Choshi (a junction of river mouth and a cape at southern tip of Ibaraki Prefecture) is about 8 m comparing to the simulation of only 2–4 m. Clearly more complicated wave reflections and interferences cannot be predicted at cape area without accurate data of the bathymetry or without including nonlinear effects. In addition, allowance of flow over land must be made along the River Mouth; hence “finite volume method” should be used for this location. Moving further North to Oarai (middle part of Ibaraki Prefecture), the initial wave is in phase with observation with comparable magnitude. The initial phases of simulations basically agree with that of observed data at Soma, and Ayukama of Ishinomaki, Ofunato, but out of phases with observations in Kamaishi, and Miyako (further North of the epicenter of the earthquake). Apparently, the propagating direction or so-called directivity of the fault rupture may play a role in generating the tsunami which was not and could take into consideration by this model. Far up North in the Hachinohe Port of Aomori Prefecture, the simulations are typically two to three times larger than the actual observations and simulations also predict an arrival time of the first wave of 15 min ahead than the actual time. This may suggest a directivity of fault rupture toward the south side of the fault

An Advanced Permanent Magnet Motor Drive System for Battery-Powered Electric Vehicles

Recent availability of high-energy neodymium-ironboron (Nd-Fe-B) permanent magnet (PM) material has focused attention on the use of the PM synchronous motor (PMSM) drive for electric vehicles (EV's). A new Nd-Fe-B PMSM is proposed for the drive system, which possesses high power density and high efficiency, resulting in greater energy and space savings. The design and optimization of the motor employ finite element analysis and computer graphics. Increasingly, a new PWM inverter algorithm is developed for the drive system, which can handle the nonconstant battery voltage source. An efficiency optimizing control is adopted to further improve the energy utilization of the drive system. Both the control strategy and the PWM generation are implemented in a single-chip microcontroller. As a result, the motor drive achieves high power density, high efficiency, and compactness. A prototype of the 3.2-kW battery-powered drive system has been designed and built for an experimental mini-EV. © 1996 IEEH.published_or_final_versio

Destabilization control of a chaotic motor for industrial mixers

Industrial mixers are among the most expensive and ineffective equipment in food, drug, chemical and semiconductor industries. Chaotic mixing has been proposed to improve the energy efficiency and the degree of homogeneity using either mechanical or electrical means. This paper presents the destabilization control of the DC motor (the agitator) for industrial mixing processes through the pole placement technique which is more analytically accessible compared with time-delay control proposed before. Theoretical derivation and computer simulation are provided to illustrate the controllable chaotic motion. Moreover, the mixing effectiveness is experimentally verified by an acid-base neutralization reaction. © 2005 IEEE.published_or_final_versio

A SPICE compatible model of permanent magnet DC motor drives

A SPICE compatible model for the computer simulation of permanent magnet (PM) DC motor drives is presented. The key of the proposed model is to take into account the armature reaction and magnet demagnetization, hence the shift of operating point at load conditions can be considered. Making use of this model, the PSpice simulation of a typical PM DC motor drive is performed. Apart from the steady-state simulation, transient behaviours of the PM DC motor drive, including start-up, sudden load change and sudden reference change conditions, have been simulated conveniently. Based on a low-cost circuit simulator-PSpice, the developed model is especially helpful for undergraduate students.published_or_final_versio

Design of permanent magnets to avoid chaos in PM synchronous machines

PURPOSE: The permanent-magnet synchronous machine (PMSM) is becoming more and more attractive for both industrial and electric vehicle applications [I] because of its inherent advantages of high power density and high efficiency. However, the investigation onto its chaos has been surprisingly little. Even so [2], the discussion was based on ac-hoc computer simulation, whereas the actual effect of PMs on the chaos in PMSMs was unexplored. In this paper, the relationship between the sizing of PMs and the chaos in PMSMs will be revealed. Both computer simulation and experimental results will be given to support the design criteria ...published_or_final_versio

Design, modeling and analysis of a brushless doubly-fed doubly-salient machine for electric vehicles

This paper presents a new three-phase 12/8-pole brushless doubly-fed doubly-salient (BDFDS) machine for application to electric vehicles. The key is to design, modeling, analyze and control the proposed BDFDS machine. The output power equation is analytically derived, and the initial calculation of machine dimensions and parameters are also discussed. By using finite element analysis, the field distributions of the BDFDS machine at different load and field current are obtained, in which the magnetic saturation and the coupling between armature current flux and field current flux are considered; moreover, the static characteristics of the proposed machine are given. Based on the static characteristics, the system mathematical model has been established. Hence, the evaluation of system performances is conducted by computer simulations in which the simulation model combines the machine with a 3-phase half-bridge converter. A 12/8-pole BDFDS machine is designed and built for exemplification, and a drive system employing this new machine has been developed and investigated experimentally. Experimental results are also given to verify the validity of the theoretical analyses. © 2005 IEEE.published_or_final_versio

Performance and cost comparison of permanent-magnet vernier machines

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Nonlinear identification of power electronic systems

This paper presents a new approach to modelling power electronic systems using nonlinear system identification. By employing the nonlinear autoregressive moving average with exogenous input (NARMAX) technique, the parametric model of power electronic systems can be derived from the time-domain data. This approach possesses some advantages over available circuit-oriented modelling approaches, such as no small-signal approximation, no circuit idealization and no detailed knowledge of system operation. Moreover, it is found that the inclusion of nonlinear terms in the model of power electronic systems is particularly necessary during the presence of large-signal perturbation.published_or_final_versio