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Computers in Power Electronics, 1996., IEEE Workshop on

Date 14-14 Aug. 1996

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Displaying Results 1 - 25 of 30
  • 5th IEEE Workshop on Computers in Power Electronics

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    Freely Available from IEEE
  • Automatability of consistent switches state search in computer aided analysis of switched RLC networks

    Page(s): 71 - 79
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    In this paper a method for the formulation of switched RLC (SRLC) circuit equations is discussed. The method is aimed at providing a suitable data structure for time-domain simulations, supporting the automatic determination of the topology entered by SRLC nets after forced commutations of any switching device. The data structure consists in a Master-Slave Connection Matrix, defined using the compensation theorem, which permits a straight evaluation of the influence of the forced commutation of any switch upon the currents of all switching devices in the net. Problems connected to the presence of controlled sources are discussed. Some applications to the simulation of power electronic circuits are presented View full abstract»

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  • On the efficacy of sampled-data modelling of switched networks

    Page(s): 14 - 17
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    The limitations of sampled-data modelling in determining the frequency response of switched networks such as switching power converters are highlighted. A general scheme for constructing small-signal difference equations used in sampled-data models is given. This scheme overcomes the limitations of current approaches used in obtaining input-to-output responses. However, in common with all other sampled-data modelling approaches, problems of accuracy and appropriate choice of formulation of difference equations still remain. Consequently, the use of sampled-data models to determine frequency response is not recommended. However, the difference equation formulation scheme developed here may be used in a small-signal describing function modelling approach which is demonstrated by the authors to be accurate, have no ambiguity of use and no frequency limitations-in contrast to sampled-data modelling View full abstract»

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  • Simulation of power angle controlled voltage source converter using a linear quadratic method in a wind energy application

    Page(s): 157 - 162
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    The design, analysis and simulation of a power angle controlled voltage source inverter in a wind energy application are addressed. By controlling both the phase displacement angle and voltage amplitude, the performance of the conversion system is improved compared with the traditional power angle control. The system becomes a multiple-input and multiple-output system preferably controlled by the linear quadratic method. To reduce harmonics and noise, a Kalman estimator is applied to the input signals of the controller. When state equations are used, the inverter system as well as the feedback and feedforward parameters are easy to handle by using the Matlab/Simulink program. The simulation results show that the proposed control method and its implementation function adequately View full abstract»

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  • Integrated design of power stage and controller for switching power supplies

    Page(s): 36 - 44
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    This paper develops a method for simultaneously designing the power stage and controller for a switching power supply. The method utilizes a numerical optimization procedure which facilitates computer-aided design. It is found that better performance can be achieved than with a traditional two-step design process where the power stage and controller are designed sequentially. Optimization and simulation results for a buck power converter are presented to illustrate the design process and benefits View full abstract»

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  • Periodic steady-state analysis of an autonomous power electronic system by a modified shooting method

    Page(s): 80 - 84
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    This paper proposes a new periodic steady-state analysis method for an autonomous power electronic system by solving a periodic steady-state condition and a switch condition simultaneously for finding initial values. The method utilizes switching operations, which are a characteristic feature of a power electronic circuit, to express a variation of a period. There is no need to include a period T as an unknown variable. This modification eliminates two disadvantages of the conventional method; one is failure of finding solutions due to wrong initial values and the other is that an initial time does not coincide with a starting time of a circuit topological mode View full abstract»

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  • Simulation studies of a resonant link converter

    Page(s): 90 - 96
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    Simulation studies of a new scheme of a resonant link converter suitable in a wide variety of applications is presented. Features of the simulation model of the converter are described. Capabilities of a single 'C' program developed to carry out extensive simulation studies of the converter while supplying different types of loads are highlighted. Results of simulation of the converter modeled as a digital power processor, while supplying different loads at low or high voltages and at fixed or variable frequencies are discussed in detail. With the locus on the variable frequency operation of the converter with potential application in variable frequency custom power delivery or adjustable speed motor drives, the converter performance characteristics, as established by the simulation studies are detailed. Scope of future work is presented along with conclusions View full abstract»

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  • Accelerators and convergence measures for Monte-Carlo synthesis techniques

    Page(s): 30 - 35
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    Monte-Carlo synthesis techniques can be used to design new and complex systems that best meet a certain objective function with relative ease. Monte-Carlo synthesis is inefficient and does not provide obvious convergence measures. Accelerators based on probability distribution function shading and discriminant vector analysis are proposed. Convergence measures based on cluster identification and a statistical criterion are proposed. These enhancements are shown to significantly improve the performance of Monte-Carlo synthesis techniques. The implementation of these enhancements is shown through an example View full abstract»

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  • Computer analysis of a power electronic system with analog-digital mixed elements

    Page(s): 25 - 29
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    This paper proposes a new efficient method which solves mixed circuit equations of a power electronic system by utilizing characteristics of not only the main and control circuits but also digital and analog elements. It consists of division of a system into groups, and scheduling of the groups. A simple power converter simulation example is analyzed and validated View full abstract»

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  • Modeling and simulation of saturated induction motors

    Page(s): 163 - 167
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    Induction motors play an important role in constant and adjustable speed drives. This paper contributes to the development of a realistic model for an induction machine taking into account the saturation and nonlinearity to compute the energy efficiency of the machine. The authors concentrate on the steady-state analysis of a saturated induction machine and present a methodology for the evaluation of the parameters of a saturated induction machine. The validation of the machine model is presented under steady-state conditions. This work provides a good starting point for the evaluation of steady-state performance of asynchronous machines under saturated and unsaturated operating conditions View full abstract»

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  • A transient behavioral model (TBM) for power converters

    Page(s): 18 - 24
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    This paper describes a new technique to model power converters. The resulting power converter model is referred to as a transient behavioral model (TBM). First, a simple buck power converter is used to demonstrate the TBM. A power converter called the dynamic voltage restorer is used to demonstrate a practical application of the TBM. It is shown that the TBM yields simulation results almost as accurate as the ideal switch model (ISM). At the same time, the TBM is computationally more efficient than the ISM. These features, coupled with the simplicity and the ease of implementation in a standard circuit simulator, make the TBM an attractive alternative to the ISM View full abstract»

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  • Power electronic circuit reliability analysis incorporating parallel simulations

    Page(s): 45 - 51
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    This paper presents and applies reliability analysis methods to power electronic circuit simulation. The focus is on the first-order reliability method (FORM). Two circuits are analyzed: an open-loop updown power converter; and a similar closed-loop circuit that is currently in mass production. The open-loop circuit provides an example from which rich quantitative data can be obtained for various methods. The closed-loop production design circuit provides a proof-of-concept for a FORM application on a complex design. The implementation includes parallel gradient computations across six networked workstations. The parallel environment is described in detail View full abstract»

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  • Analyzing power MOSFET breakdown voltage using simulators

    Page(s): 136 - 141
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    A comprehensive analysis of the performance of the power MOSFET using process and device simulators is described. The power MOSFET process is simulated using TSUPREM and the simulated profile is used as an input to MEDICI to simulate the device performance. The dependence of the breakdown voltage on the device parameters, epi-layer thickness and doping concentration, and the parameter variations are used to establish the values of design parameters for the target breakdown voltage and desired yield View full abstract»

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  • Identification of DC-DC switching converters characteristics for control systems design using interval mathematics

    Page(s): 97 - 104
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    In this paper the problem of identifying DC-DC switching converters characteristics in the presence of parameters uncertainties is dealt with. An interval mathematics (IM) approach is adopted to evaluate the interval extensions of DC conversion ratio and AC frequency response of switching converters, to be used in control systems design, accounting for the joint action of all the uncertainty sources. The analysis of a DC-DC quadratic converter is considered, with a discussion of various techniques for minimizing the IM overestimate of true sensitivity. The differences between the results obtained using both averaging-based and exact models are highlighted and the most remarkable computational aspects connected to IM-based numerical computing are emphasized View full abstract»

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  • Analysis by finite element method of a coupled inductor circuit used as current injection interface

    Page(s): 147 - 151
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    In the case of three-phase diode bridge rectification, the harmonic content of the input currents can be reduced by injecting a calculated amount of third harmonic current on the AC side. The paper presents an analysis, by the finite element method, of a magnetic device (coupled three-phase inductor) used as current injection interface in a third harmonic modulation circuit. The magnetic device is designed to block fundamental currents and to offer least resistance to third harmonic currents. In order to reduce its zero sequence inductance, which may affect the operation of the diode bridge, a conductive shield is added to cover the coupled inductor. On the other hand, the conductive shield produces excessive power losses due to high eddy currents induced by the third harmonic field. The electrothermal aspect of the coupled inductor is therefore investigated. The analysis is performed using a realistic 3D model of the magnetic device View full abstract»

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  • A general-purpose driver for spindle motors in rigid disk drive applications

    Page(s): 176 - 181
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    Over the past few years, disk drive capacities and performance have changed for the better in a dramatic fashion. While disk drives in personal computers only a few years ago had capacities of a few hundred megabytes, storage capacities of an order of magnitude greater are increasingly commonplace. The disk drive essentially consists of one or more disks which store the data, spinning at a high rotational speed, usually of the order of a few thousand revolutions minute (RPM). An actuator which supports suspension for the data accessing heads moves over the data surfaces of the disk(s) and transfers data to and from the other parts of a computer. Since, based on capacity, the number of data disks can vary from one to ten (or even higher), and the rotational speed can vary over a wide range, the spindle motors used in these disk drives can be of very different designs View full abstract»

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  • Worst case stability analysis of switching regulators using the structured singular value

    Page(s): 105 - 112
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    A method to assess the effect of component tolerances on the stability of closed loop switching regulators is given. Use of μ, the structured singular value, is made which obviates the need for time intensive Monte-Carlo simulation runs and also guarantees the assessment of the worst case condition of the system. Furthermore, through the use of newly developed software routines for μ, the effect of up to a hundred uncertainties may be taken into account. The analysis procedure entails isolating component value uncertainties from the nominal system and arranging into a standard Δ-M structure. Subsequent determination of μ for this structure along with the small-gain theorem enables a robustness assessment to be made for the system under study. Two procedures are given which enable reduction of a switching regulator system to Δ-M form. The first considers uncertainties to exist only in inductor and capacitor values. The other extends the formulation to encompass resistance uncertainties as well. An example is given of a regulator design for which an assessment is made of the allowed component tolerances which guarantees a lower limit of the phase margin View full abstract»

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  • Simulation of distribution feeders and charger installation for the Olympic electric tram system

    Page(s): 168 - 175
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    This paper discusses a simulation study of the effects of operating large quantities of battery chargers on an electric utility distribution system. Harmonic effects are modeled with Electrotek's SuperHarm program, part of the HarmFlo+ workstation package. During the operational period of the tram battery charging facility, measurements at different points along the distribution system were taken and compared to results predicted by SuperHarm. Once the accuracy of the simulation model was confirmed, specific scenarios involving capacitor arrangement, IEEE 519 compliance and charger comparisons were investigated View full abstract»

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  • Analysis of networks with ideal switches

    Page(s): 9 - 13
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    The paper describes SWANN, a computer program for the fast simulation of nonlinear switched analog networks. Switching elements, like diodes or transistors, can be modeled as open and short circuits. The program accepts all linear elements; nonlinear elements are modeled by cubic splines. Using a new theory, the program overcomes switching transients of ideal switches with only four integration steps and gives correct responses after switching. It allows the accelerated steady-state analysis of periodic networks and the harmonic content of steady-state responses is provided View full abstract»

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  • Role of parasitic BJT in the design of DMOSFET

    Page(s): 128 - 131
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    Use of device simulation programs in teaching power semiconductor devices courses is illustrated. A design procedure for DMOSFET is outlined and use of simulation to analyze device behavior is illustrated. It is shown that the parasitic BJT plays a very important role and the device design should try to minimize it from the very beginning. Usefulness of the device simulation in the analysis of the device operation is demonstrated. Some of the common problems in using simulation are given and remedies provided View full abstract»

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  • A computer method for finding operating mode boundaries in power electronic circuits by curve tracing

    Page(s): 66 - 70
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    In designing a power electronic circuit, it is often required to find the regions of the circuit parameters such that the circuit takes an operating mode. This paper describes a general computer method for determining the operating-mode boundaries in power electronics circuits. In general, the conditions of operating-mode boundaries in power electronic circuits are expressed by nonlinear algebraic equations, the solutions of which are curves in parameters space. The operating-mode boundaries are obtained by tracing the solution curves by using the concept of the homotopy continuation method View full abstract»

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  • A design methodology for power electronics

    Page(s): 52 - 57
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    Currently there are no computer-aided-design (CAD) tools dedicated to the design and synthesis of power electronic circuits. The design process has not been formalized, and most of the efforts in computer tools have been oriented towards simulation, neglecting other stages of the design process that can also benefit from their use. This paper presents an outline of the structure of an automated power converter circuit design tool. The different parts of this tool are described along with the problems that make them difficult or interesting. Current progress in the development of some of these parts is also presented View full abstract»

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  • Analysis and simulation of digitally-controlled grid-connected PWM-converters using the space-vector average approximation

    Page(s): 85 - 89
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    A technique to evaluate the dynamic performance of control principles for PWM-converter systems is presented. In the modelling of vector-controlled, grid-flux-oriented control systems, nonlinear switches and time-varying elements due to coordinate transformation occur in the feedback loop. By using space-vector averaging, coordinate transformations and nonlinear switches are avoided. A linear time-invariant analytical model in the grid-flux-oriented dq-frame is derived. Simulations with a switched PWM-model and an analytical model show accurate transient response and frequency response View full abstract»

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  • Modelling and implementation of space vector PWM techniques in active filter applications

    Page(s): 142 - 146
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    Active filters use power converters to inject equal but opposite harmonics into the system, thus neutralizing the effect of the load harmonics. In this paper, the space vector PWM technique is applied to active power filter systems. A systematic way of simulating the space vector technique in a general-purpose simulation program is described and simulation results are provided in the paper View full abstract»

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  • PETS-a simulation tool for power electronics

    Page(s): 1 - 8
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    This paper describes PETS (Power Electronics Transient Simulator), a computer program for the time-domain analysis of power electronic circuits. Methods implemented in PETS include standard techniques such as the modified nodal approach to forming system equations and numerical integration with automatic time-step control, together with new techniques including a state determination algorithm and representation of elements to maintain a constant system matrix. The simulator supports arbitrarily complex piecewise-linear models and smooth nonlinear models using a delay approximation. The methods implemented in PETS are illustrated using two examples: a quadratic buck power converter, and a closed-loop power factor corrector View full abstract»

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