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Power Electronics Specialists Conference, 1989. PESC '89 Record., 20th Annual IEEE

Date 26-29 June 1989

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Displaying Results 1 - 25 of 129
  • A practical comparison of high frequency off-line power converter topologies

    Page(s): 979 - 986 vol.2
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    Three half-bridge power converters, employing resonant techniques to shape the high-frequency switching waveforms, are compared for offline 12 V, 10 A output applications. The operation of the zero-current- and zero-voltage-switched quasi-resonant converters is reviewed, along with that of the parallel resonant converter. Particular attention is paid to the distribution of the resonant inductance around the transformer. Each converter is designed to operate at a similar switching frequency under full-load, low-line conditions. A loss analysis is carried out for each converter, and suggestions for improving the efficiency are made. The three topologies are breadboarded and the practical results evaluated. Waveforms are provided and discussed for each circuit at full load. The zero-current-switched quasi-resonant converter is identified as the circuit capable of offering the highest power density for a given maximum power dissipation.<> View full abstract»

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  • PESC '89 Record. 20th Annual IEEE Power Electronics Specialists Conference (Cat. No.89CH2721-9)

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    Freely Available from IEEE
  • General properties and synthesis of PWM DC-to-DC converters

    Page(s): 515 - 525 vol.2
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    General properties that interrelate network complexity, attainable conversion ratios, and switch stresses are derived for pulse-width-modulated (PWM) DC-to-DC converters. The emerging synthesis procedure guarantees that complete classes of converters that satisfy a set of prescribed specifications are generated. The input specifications include the desired DC conversion ratio, nonpulsating terminal currents, possible coupling of inductors, the allowed number of switches, and, in particular, the number of active transistor switches. As a result, a number of novel PWM topologies are uncovered View full abstract»

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  • High performance current control techniques for applications to multilevel high power voltage source inverters

    Page(s): 672 - 682 vol.2
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    Several high-performance current-control techniques have been developed for applications to multilevel high-power voltage source inverters. The logical sequence of the design choices is described. They result in a very robust and reliable control system that allows an adequate switching optimization and excellent dynamic responses. The advantages of using various accessible DC potentials have been fully exploited. The results obtained by digital simulation refer to five-level voltage waveforms, but the current-control strategies developed can easily be applied to any multilevel inverter structure, even in the case of n-level voltage waveforms. The validity of the proposed schemes has been confirmed by both digital simulations and tests carried out on scale models View full abstract»

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  • Multi-objective design optimization technique for switching regulators using mixed-discrete programming

    Page(s): 526 - 533 vol.2
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    A multiobjective design optimization model for switching regulators is presented. A mixed-discrete nonlinear programming technique is adopted to solve the optimal design problem. The design parameters obtained can be directly used in practice. The proposed design technique is flexible and effective, as verified by two design examples and SPICE-2 simulations View full abstract»

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  • Instability, subharmonics and chaos in power electronic systems

    Page(s): 34 - 42 vol.1
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    The principles of chaos theory are applied to a variety of nonlinear power electronic circuits. With the onset of instability, the phenomena of subharmonics, quasi-periodicity, and chaos are predicted and observed. Examples treated are: diodes with charge storage (with application to resonant converters); a ferroresonant circuit; a controlled thyristor rectifier circuit; and a buck converter controlled by pulse-width modulation View full abstract»

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  • A discrete approach to the modelling of power electronic switching networks

    Page(s): 130 - 137 vol.1
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    A novel approach to time-domain analysis and modelling of power electronic circuits is presented. All circuit components, including active and passive elements, are modeled in a discrete manner by transmission-line sections using the transmission-line modeling (TLM) method. The method requires a fixed system matrix that depends only on the circuit configuration and not on the switching states of the circuit. The circuit transient behavior can be modeled easily. The proposed TLM algorithm, which provides a fast and exact solution to the discrete model, can be programmed easily on a desk-top computer and is stable even for stiff networks View full abstract»

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  • Switched filter for the compensation of power processors

    Page(s): 534 - 539 vol.2
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    An analog-amplitude, discrete-time recursive filter is proposed for the frequency compensation of power processors. It was applied to a Cuk converter and allowed an almost ideal profile of Gloop to be reached. The filter copes with converters that chop up to 0.5 MHz and seems to be better than time-invariant compensation networks and digital-signal-processing-based filters. An exact small-signal analysis of the switching cell and the compensation filter is carried out, and experimental results on gain and phase frequency dependence are reported View full abstract»

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  • 1200 V 20 A integrated light triggered and quenched static induction thyristor (LTQ SI thyristor)

    Page(s): 322 - 329 vol.1
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    A monolithic light-triggered and quenched static induction (LTQ SI) thyristor, whose forward blocking voltage is 1200 V and whose current capacity exceeds 20 A, has been fabricated and investigated. This device is optically switched at 800 V and 16 A with a turn-on time of 2.8 μs and a turn-off time of 6.5 μs. Such switching speed is achieved by adopting an anode-emitter short structure as a double gate structure. An on-state voltage is maintained as low as 2.5 V at the anode current of 20 A by optimizing the anode-emitter short structure View full abstract»

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  • MCTs and IGBT: a comparison of performance in power electronic circuits

    Page(s): 163 - 169 vol.1
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    There is a continuous demand for improvements in the quality of switching power devices, such as higher switching frequency, higher withstand voltage capability, larger current-handling capability, and lower conduction losses. However, for single-conduction-mechanism devices (SCRs, GTOs, BJTs, FETs), possessing all these features is probably unrealizable for physical reasons. An attractive solution appears to be double-mechanism devices, in which the features of both a minority carrier device (BJT or SCR) and a majority carrier device (MOSFET) are embedded. Both IGBTs (insulated-gate bipolar transistors) and MCTs (MOS-controlled thyristors) belong to this family of double-mechanism devices and promise to have a major impact on converter circuit signs. The authors deal with the major features of these two devices, pointing out those that are most critical to the design of power converter topologies. In particular, the two devices have been tested both in a chopper and in two resonant link converter topologies, and the experimental results are reported View full abstract»

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  • Novel space vector based current controllers for PWM-inverters

    Page(s): 657 - 664 vol.2
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    Two simple control strategies for current-controlled VSI-PWM (voltage-source-inverter-pulse-width-modulated) transistor inverters are presented. Both methods are based on three-level hysteresis comparators that select appropriate inverter output voltage vectors using a switching EPROM table. The first controller works with current components represented in a stationary coordinate system (AC components) and the second with components represented in a rotated (field-oriented) coordinate system (DC components). The theoretical principles of these methods are discussed. The results of a comparative study are presented which illustrate the performance of the proposed controllers in comparison to the most popular scheme, based on three independent two-level hysteresis comparators View full abstract»

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  • A nonlinear resonant switch

    Page(s): 43 - 50 vol.1
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    A resonant switch is introduced which uses nonlinear tank elements. Zero current switching is obtained, yet the peak transistor voltage and current stresses can approach those of an equivalent ideal PWM (pulse-width-modulated) converter. Reduced switching loss without a substantial increase in conduction loss is therefore possible. An approximate analysis is outlined, and transistor peak voltage and current stresses are shown to be much lower than those of linear resonant switch technologies. Single-transistor implementations of the buck, boost, and buck-boost nonlinear resonant switch converters are given. The validity of the nonlinear resonant switch concept, as well as of the approximate analysis, is proven experimentally View full abstract»

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  • Modeling of quantum parallel resonant converters-a new parallel resonant converters controlled by integral cycle mode

    Page(s): 744 - 751 vol.2
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    Quantum parallel resonant converters (QPRCs), a dual converter of quantum series resonant converters (QSRCs), and a subset of parallel resonant converters (PRCs) operating on zero-voltage switching conditions are modeled. It is shown that the QPRC can be operated as a Cuk converter with an equivalent capacitor, or as a buck or buck-boost converter with an additional equivalent capacitor. The approach to modeling these converters is verified by analysis and simulation results for the PRC. DC and AC characteristics of the quantum PRCs can be obtained from these models. Therefore, the QPRC can be designed to be similar to the QSRC, i.e. to be controlled with closed-loop feedback and to have advantages such as low device switching stress, reliable high-frequency operation, low electromagnetic interference, etc View full abstract»

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  • Position and mechanical impedance control method of robot actuators based on the acceleration control

    Page(s): 423 - 430 vol.1
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    A novel hybrid control method for the position and mechanical impedance of robot actuators is proposed and is based on the acceleration control previously presented by the author (1988). Because the acceleration controller suppresses the disturbance forces effectively and makes each joint fully independent of the others, simple decentralized controllers can be designed based only on the angle command for each joint. The author shows the superiority of the proposed system by comparing it with the resolved-acceleration control method View full abstract»

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  • A new conceptional PWM DC-DC converter with zero-voltage switching incorporating non-controlled saturable reactors

    Page(s): 881 - 888 vol.2
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    A constant-frequency, phase-shifted-mode, PWM (pulse-width-modulated) DC-DC power converter is described which incorporates two-stage inverters with high-frequency transformer links and saturable reactors as nonlinear elements. The proposed converter performs efficient zero-voltage switching over a large load range (no limitation for load range) and a wide voltage regulation range. Its steady-state characteristics are evaluated and discussed on the basis of computer simulation and experimental results. The experiments were carried out with a 0.5 kW 500 kHz breadboard, and power conversion efficiency of more than 88% was obtained View full abstract»

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  • The state-space analysis of excitation regulation of self-controlled synchronous motor with constant margin-angle control

    Page(s): 791 - 798 vol.2
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    A mathematical model of the self-controlled synchronous motor with finite DC inductor and main flux saturation effects considered is established, and its steady-state performance under constant margin-angle control is investigated on the basis of simulated waveforms. The mechanical characteristics and the corresponding excitation regulation, which ensures that the motor operation is stable, are obtained View full abstract»

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  • Calculating the short-circuit impedances of a multiwinding transformer from its geometry

    Page(s): 607 - 617 vol.2
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    By considering the set of short-circuit tests which can be performed on a multiwinding transformer, analytical expressions are derived for the leakage inductances between all pairs of transformer windings, expressions which depend only on the winding geometry and the frequency of excitation. For each short-circuit test, a simplified field analysis gives the complete solution for the frequency-independent magnetic field intensity between winding layers, and the frequency-dependent distribution of magnetic field intensity within each layer. Then, for any frequency of interest, the magnetic energy stored in each winding layer and interlayer space is calculated, and the results are summed to give the total energy stored in the entire winding space of the transformer. Finally, the leakage inductance between excited and short-circuited windings is derived from the total stored energy. Experimental data are provided that illustrate the accuracy and the limitations of such leakage-inductance calculations as well as the accuracy of AC-winding-resistance calculations carried out using a similar, previously published method View full abstract»

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  • Single switch dual output DC-DC converter performance

    Page(s): 540 - 547 vol.2
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    The performance of a single-switch dual-output DC-DC converter is evaluated. This converter regulates two independent DC outputs supplied from a single DC voltage source using a power semiconductor switch. Two discrete proportional feedback control loops regulate the duration of on-switching and off-switching. The duty cycle of the switch controls one output voltage, supplied from a low-pass filter, while the switching frequency regulates the other output voltage, supplied from a higher frequency bandpass filter. The control algorithm is implemented with an Intel 8096 microcontroller. The experimental data demonstrate the actual circuit performance and confirm the simulation results View full abstract»

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  • 8000 V 1000 A gate turn-off thyristor with low on-state voltage and low switching loss

    Page(s): 330 - 336 vol.1
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    An 8000 V, 1000 A gate turn-off thyristor (GTO) has been developed. Low on-state voltage and low switching loss are realized with a combination of a p-i-n structure and a novel ringed-anode short structure. The p-i-n structure is fabricated by using both a diffusion technique and an epitaxial growth technique. The device's structure, the p-i-n base process, and the electrical characteristics of the GTO are discussed View full abstract»

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  • Analysis of high-frequency resistance in transformers

    Page(s): 618 - 624 vol.2
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    An accurate, analytical method is proposed for calculating the lead and winding high-frequency resistance of complex transformer constructions. High-frequency resistance is derived from the resulting matrix system equations, common to the leads and windings. The effect of eddy currents in the leads is confirmed by theoretical results. The high-frequency resistances of three winding arrangements are compared, and a winding geometry that reduces winding high-frequency resistance is derived View full abstract»

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  • Current waveform distortion in power factor correction circuits employing discontinuous-mode boost converters

    Page(s): 825 - 829 vol.2
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    For active power factor correction circuits employing discontinuous-mode boost converters, the line current will automatically follow the sinusoidal line-voltage waveform. However, due to the modulation of the input inductor current discharging time, there is certain distortion in the AC line-current waveform. It is found that the modulation of inductor current discharging time is a function of the line voltage and the output voltage of the boost converter. For practical design considerations, the waveform distortion and the maximum power factor achievable are derived and presented in a graph form as functions of the ratio of line voltage to output voltage View full abstract»

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  • A three phase fully regenerative converter for chopper controlled DC drives

    Page(s): 563 - 570 vol.2
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    A three-phase AC-DC converter allowing regeneration of the energy recovered by a four-quadrant chopper is presented and analyzed. The two-quadrant chopper is presented and analyzed. The two-quadrant three-phase bridge, using diodes in parallel with reverse connected transistors, replaces the diode bridge of the standard chopper configuration. This converter allows natural bidirectional current flow. Gating of the transistor coincides with the conduction of the corresponding diode. The DC bus inductor, capacitor, and braking resistor are eliminated. Experimental results confirm that the converter is fully regenerative and that transfer from motoring to regeneration is instantaneous. The overall performance of the system is comparable to that of the conventional four-quadrant chopper and far superior to that of the standard four-quadrant dual-bridge thyristor converter View full abstract»

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  • Safe operating area of power DMOS FETs

    Page(s): 170 - 175 vol.1
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    The physical origin of the safe-operating-area (SOA) limitation in power DMOSFETs lies in the parasitic bipolar junction transistor (BJT) which is inherent to these devices. Direct-current SOA depends on transconductance and thermal variations of the drain-to-source current, while short-circuit SOA is strongly dependent on transconductance and the transient thermal impedance of the packaged device. It is shown that the power DMOSFET is inherently thermally stable. However, for operation at high voltages and low currents (DC-SOA), the built-in parasitic BJT could turn on locally due to solder voids, local high thermal impedance, and/or BJT cells with higher gain. Turn-on of the built-in BJT will cause device failure, limiting DC-SOA. DC-SOA can be improved with a lower temperature coefficient for drain current, which implies lower transconductance and thus improves SC-SOA due to lower power dissipation View full abstract»

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  • A novel UPS using high-frequency switch-mode rectifier and high-frequency PWM inverter

    Page(s): 53 - 57 vol.1
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    An uninterruptible power supply (UPS) resorting to high-frequency switch-mode rectifier (SMR) techniques and high-frequency pulse-width-modulated inverter techniques has been developed. The input current of UPS is controlled to maintain a sinusoidal waveform by SMR, and the output voltage waveform distortion is suppressed to a low level by instantaneous voltage control. This UPS is suitable for a protector of computer-applied equipment View full abstract»

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  • Dynamic characteristics and stability analysis of resonant converter

    Page(s): 752 - 759 vol.2
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    A general method of analysis for resonant converters is presented. This analytical method generalizes the averaging technique to overcome the limitations of the conventional state-space-averaging method, which prevents it from being applied to resonant converters. As the result, the dynamic characteristics as well as the static characteristics of resonant converters are made clear, and the analytical expressions for transfer functions and stability conditions are obtained View full abstract»

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