Charles W. Brice

Review of technologies for current-limiting low-voltage circuit breakers

Conventional air-magnetic circuit breakers, which are widely used in low-voltage applications, utilize magnetic forces that are produced by blowout coils, the geometry of the arcing contacts, or both. The magnetic forces act to push the arc off the contacts into an arc chute, which consists of a number of metal plates. The arc chute causes the arc to be split into a number of smaller arcs, thereby facilitating the process of extinguishing the arc. In the last 20 years, the technology of circuit breakers has dramatically advanced, now including mature devices based on gas-blast (such as SF/sub 6/) and vacuum interruption. At the same time, the technology of power electronic devices has evolved rapidly, leading to suggestions of a purely static circuit breaker based on solid-state electronic devices. Recently, several different proposals have appeared for current-limiting devices to be used in conjunction with or in replacement of conventional circuit breakers. The technologies involved in these proposals have ranged from very familiar (series reactors) to quite innovative (conductive polymer devices). Several of these proposed technologies have been used to a limited extent in commercial products, but they are very likely to see increasing applications as the technology matures. This paper begins with a short review of conventional circuit breaker action for background, then reviews the recent literature for current-limiting technologies that could be applied to low-voltage electric power systems. The paper concludes with a description of work underway for further development of conductive polymer current limiters.

Design and simulation of a permanent-magnet electromagnetic aircraft launcher

This paper describes the basic design, refinement, and verification using finite-element analysis, and operational simulation using the Virtual Test Bed, of a linear machine for an electromagnetic aircraft launcher, for the aircraft carrier of the future. Choices of basic machine format and procedures for determining basic dimensions are presented. A detailed design for a permanent-magnet version is presented, and wound-field coil and induction machine versions are briefly discussed. The long armature-short field geometry is justified, and in particular the impact of this geometry on the scale of the power electronic drive system is examined.

A virtual prototype for a hybrid electric vehicle

A virtual prototype of a hybrid electric vehicle (HEV) is created within the virtual test bed (VTB) environment, which has been developed for modeling, simulation, analysis and virtual prototyping of large-scale multi-technical dynamic systems. Attention is focused on the electric system, which is composed of (i) a fuel cell system as a prime power source, (ii) battery and super capacitor banks as energy storage devices for high and intense power demands, (iii) DC-to-DC power converters to control the flow of power, (iv) a three-phase inverter-fed permanent magnet synchronous motor as a drive, and (v) a common DC bus. The simulation of the proposed system is conducted using two types of driving cycles. These are: (i) rapid acceleration and deceleration, and (ii) Federal Urban Driving Schedule (FUDS). The parameter values chosen for the components and the numerical results obtained by simulation are consistent with the practical HEV applications.

Modeling and System Identification of Residential Air Conditioning Load

A fairly detailed physically-based model of the residential air condit

Design and simulation of an electromagnetic aircraft launch system

oning system is presented. It has been shown that the paramstors of tho model can be identified by making a sequenco of measuremonts of on/off cycles of the air conditioner and the onvironment variables. A scheme to determine aggregate demand of the air conditionors using duty factors is presented. The effect on energy consumption and poak duty fa9tor of change in model parameters is determined. Also, the effect of reduction in the supply voltage is studied using this model and it has been found that the steady state air conditioning load is insonsitivo to voltage reduction.

Estimation of induction motor parameters by a genetic algorithm

This paper describes the basic design, refinement and verification using finite element analysis (FEA), and operational simulation using the virtual test bed (VTB), of a range of candidate linear machines for an electromagnetic aircraft launching system (EMALS) for the aircraft carrier of the future. Choices of basic machine format, and procedures for determining basic dimensions are presented. A detailed design is presented for a permanent magnet version, and wound field coil and induction machine versions are introduced. The long armature - short field geometry is discussed, and in particular the impact of this geometry on the scale of the power electronic drive system is presented.

Time-Frequency-Based Instantaneous Power Components for Transient Disturbances According to IEEE Standard 1459

Textbook equations are available to calculate the torque that AC motors can provide. Quite often, the procedures outlined in textbooks for the determination of motor parameters only apply to small AC motors that can be tested in a lab. This paper covers the application of genetic algorithms to use motor nameplate data along with rated values such as voltages, currents and torque data to determine unknown operating motor parameters for an AC induction motor. These parameters can be used with textbook equations to offer solutions to load requirements and capabilities.

Passivity-based control of saturated induction motors

IEEE Standard 1459 defines the power components based on the fast Fourier series. However, Fourier series assumes the signal is periodic in nature, and provides erroneous assessment of the power components in the presence of transient signals. Therefore, a new method is proposed for the evaluation of the IEEE Standard 1459 power components based on the time-frequency distribution (TFD) and the cross time-frequency distribution (XTFD) of transient signals. The TFD and XTFD preserve simultaneous time and variable frequency information of transient signals, and estimate the instantaneous power components according to IEEE Standard 1459. Results of computer simulated and real-world power quality disturbance case studies justify the effectiveness of the proposed method for the assessment of instantaneous power components under transient conditions.

A virtual test bed for power electronic circuits and electric drive systems

A passivity-based controller, which takes into account saturation of the magnetic material in the main flux path of the induction motor, is developed to provide close tracking of time-varying speed and flux trajectories in the high magnetic saturation regions. The proposed passivity based controller is experimentally verified. Also, a comparison between the controllers based on the saturated and nonsaturated magnetics is presented to demonstrate the benefit of the controller based on the saturated magnetics.

Graphical and visual simulation of electric drive systems

Applications of the virtual test bed (VTB) to a power electronic circuit and an electric drive system are described. The VTB is a software environment that has been developed for design, analysis and virtual prototyping of large-scale multi-technical systems. It has the capability of integrating models, which have been created in a variety of languages such as SPICE, ACSL and SABER, into one simulation environment. It also provides advanced visualization of simulation results including full-motion animation of mechanical components. These two important features of the VTB are utilized in the modeling and simulation of a power electronic circuit and an electric drive system.