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Power Electronics Specialists Conference, 1998. PESC 98 Record. 29th Annual IEEE

Date 22-22 May 1998

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  • 29th Annual IEEE Power Electronics Specialists Conference [front matter]

    Page(s): i - ii
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    Freely Available from IEEE
  • Table of contents

    Page(s): x - xxxi
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  • Gate-drain capacitance behaviour of the DMOS power transistor under high current flow

    Page(s): 1716 - 1719 vol.2
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    The gate-drain capacitance of a power DMOS transistor was measured under high current conditions of up to 250 A. Depending on V/sub GS/ a strong nonlinear characteristic was observed. Using the measured capacitance data the characteristics of the inner MOS transistor and the epi region have been determined separately for parameterisation and modelling. View full abstract»

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  • Author's index

    Page(s): 2137 - 2141
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  • A high-power-factor constant-frequency electronic ballast for metal halide lamps

    Page(s): 1755 - 1760 vol.2
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    An electronic ballast with a novel circuit topology of a DC-linked high-frequency resonant inverter is implemented for driving metal halide lamps. The DC-link voltage of the electronic ballast is self-adjusting to meet the requirements for both starting and steady-state operation. In addition, the proposed approach performs a current shaping function, leading to a high power factor at the input line View full abstract»

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  • Utilization of the power losses map in the design of DC/DC converters

    Page(s): 1543 - 1547 vol.2
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    In this paper, the authors propose a power losses map in order to optimize the design of DC/DC power converters. The power losses map is a level curves graph which shows, in advance, the theoretical power losses at the different operation-points where it is possible to design a DC/DC power converter, under the same specifications. They present the use of the power losses map especially when there are some restrictions in the design, such as the converter size, the magnetic core size, the maximum drain-source voltage, the conduction mode, when some component is imposed, etc. Finally, a comparison between both the theoretical power losses map and experimental results from flyback power converters is also presented View full abstract»

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  • Position control of ultrasonic motors using variable structure type adaptive control

    Page(s): 1860 - 1866 vol.2
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    This paper proposes a position control method of ultrasonic motors (USMs) using variable structure type adaptive control. The aim of the controller is to achieve robust adaptive position control. The proposed controller performed quick and precise position control by both drive frequency and phase difference control of USM View full abstract»

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  • Switched capacitor interleaved dual-boost regulator with sliding mode control

    Page(s): 1523 - 1528 vol.2
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    The interleaving connection of two identical boost regulators originates a new step-up power converter whose closed-loop dynamics are asymptotically stable with good start-up and excellent load regulation when a self-oscillating sliding control law is applied to the power converter. For a duty cycle of 50% the new regulator acts as a small ripple voltage quadruplier View full abstract»

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  • High-temperature performance characterization of buck converter using SiC and Si devices

    Page(s): 1561 - 1567 vol.2
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    There is an increasing need for power electronic devices well beyond the military requirement of 400 K. The current More Electric Initiative demands high temperature and high power electronic circuits for use in power management and distribution in advanced aircraft systems. In an attempt to develop electronic power devices for high temperature applications, silicon carbide (SiC) Schottky diodes and MOSFETs were investigated in the temperature range of 300 K to 600 K. In order to compare the advantages of enhanced SiC devices performance over silicon (Si) devices, the on-resistance of silicon carbide and silicon Si power MOSFETs were measured as a function of temperature. Expressions for the conduction losses in a MOSFET and a diode as a function of temperature for a PWM buck DC-DC converter. Power losses are compared for SiC and Si MOSFETs and diodes in the buck converter View full abstract»

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  • Generalized digital redesign method by N-delay control and its application to motion control

    Page(s): 1835 - 1841 vol.2
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    A new digital redesign method is proposed for feedback control systems, by which the states in the continuous-time system are completely reserved in the redesigned sampled-data system. The features of the proposed method are: (1) the N-delay control is employed, and the lth plant input is changed Nl times during one sampling period; (2) the states of the redesigned sampled-data system completely match those of the original continuous-time closed-loop system at every sampling period; and (3) the proposed redesign method can be applicable for a state-feedback and/or a dynamic controller. An illustrative example of position control using a DC servo motor is presented. The advantages of the proposed redesign approach are demonstrated both in the time and frequency domains View full abstract»

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  • Noise reduction by torque ripple suppression in brushless DC motor

    Page(s): 1397 - 1401 vol.2
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    The acoustic noise of a brushless DC motor is thought to be partly due to torque ripple. This paper examines, both analytically and experimentally, the effect of ripple reduction on the noise reduction. To realize the torque ripple reduction an overlapping of phase current is utilized here. In the simulation, motor parameters such as inductance, and counter EMF are derived from two dimensional FEM of magnetic field analysis. The characteristics of currents, voltages and torque of the motor are analyzed by using our own circuit simulator. It is clarified that the current overlapping is useful for the torque ripple reduction and noise reduction View full abstract»

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  • New generation of switched capacitor converters

    Page(s): 1529 - 1535 vol.2
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    This paper presents a new generation of switched capacitor power converters. These new circuits use a reduced number of switches. The new family consists of three circuit topologies: double; inverting; and half the input voltage. All the switching devices are zero-current switching and hence the converter can operate at high switching frequency. The high switching current has also been reduced View full abstract»

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  • Active clamped ZVS forward converter with soft-switched synchronous rectifier for maximum efficiency operation

    Page(s): 1237 - 1242 vol.2
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    An active-clamped, zero-voltage switched forward power converter equipped with a soft-switched synchronous rectifier is designed and implemented for low output voltage applications where maximized efficiency is of utmost importance. The power converter efficiency is maximized due to the soft-switching of the main active clamp and the synchronous rectifier MOSFET switches. Experimental results are presented for a power converter with a DC input voltage of 48 V, an output voltage of 5 V and a DC electronic load up to 10 A. The measured efficiency was 92% for an output power of 50 W View full abstract»

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  • Zero-voltage-transition topologies for Cuk converters

    Page(s): 930 - 935 vol.2
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    With continuous input and output current, wide output voltage range and small output filter, Cuk topology has gathered more and more attention. Soft switching is especially important to a Cuk converter because the power handling capability requirements of semiconductor devices are higher than those of other topologies. Several kinds of zero-voltage-transition (ZVT) topologies newly proposed can be applied to Cuk converters to achieve soft switching. These ZVT topologies combine both merits of conventional PWM converters and resonant converters. The power switches in the ZVT topologies commutate under zero-voltage-switching by aid of resonant snubber cells during short ZVT time. Circuit operations are identical to common PWM topologies during test time. Four classes of ZVT topologies for Cuk converters with power MOSFETs employed as power switches are discussed in this paper. Qualitative descriptions and experimental results are presented to illustrate each class of ZVT topology View full abstract»

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  • MOSFET synchronous rectification with constant current transformer reset circuit

    Page(s): 1219 - 1224 vol.2
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    This paper examines a synchronous rectification of a forward converter that uses a constant-current circuit for the transformer reset. To reduce loss in the constant-current circuit, the converter is connected to supply some of the power to the load. The question of optimizing the reset power is considered and the power distribution is shown. The reset power was set to its optimum value, and experimental values were used to examine this. We also investigated operations under no-load and show that the converter operates normally and that the reset is being performed View full abstract»

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  • A unified approach to switched reluctance drive modeling: application to an axial flux (SRAF) motor

    Page(s): 1681 - 1686 vol.2
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    The paper presents a general modeling approach to switched reluctance drives with or without mutual coupling. Central to our approach is to use a model based on differential equations written in terms of current rather than flux linkage. Extensive use is made of bivariate splines to represent the flux linkage, coenergy, torque characteristics as well as the flux linkage derivatives with respect of current and angle. The method was applied to a novel axial flux type doubly salient motor known as a switched reluctance axial flux (SRAF) motor. Details of this motor are provided in this paper View full abstract»

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  • A comparison of steady state methods for power electronic circuits

    Page(s): 1084 - 1090 vol.2
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    This paper presents a comparison of the following steady state methods for power electronics: Newton's method with analytically determined Jacobian, Newton's method with numerically determined Jacobian, Newton's method with Broyden updates of an initial numerically determined Jacobian, Newton's method with a globally convergent strategy (and numerical Jacobian), Bukowski's method and Skelboe's method. Each algorithm is incorporated into a very accurate power electronics' simulator (PECS) at source-code level and compared on a common basis. The results on several switching converters suggest the analytical Newton's method to be the most accurate and fastest. When analytical derivatives are not available, both Broyden's and Skelboe's methods are competitive View full abstract»

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  • Comparison of small-signal dynamics of BIFRED and single-stage cascaded boost-and-flyback PFC converters

    Page(s): 1111 - 1117 vol.2
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    Single-stage power-factor-corrected (PFC) regulators employing a discontinuous-mode boost power converter and a flyback power converter have been proposed recently. This paper gives a detailed analysis of the small-signal dynamical response of this type of power converters, and explains how the relative sizes of the storage and output capacitors affect the dynamics. Complete sets of small-signal transfer functions are derived for two typical configurations, namely BIFRED and SSIPP. In particular, the authors have shown that when the boost part operates in discontinuous mode and the flyback part in continuous mode, the duty-ratio-output transfer function of the BIFRED can be reduced to a simple second-order minimum phase function whereas that of the SSIPP can be reduced to a second-order nonminimum phase function under certain conditions. Moreover, due to the occurrence of pole-zero cancellation, the SSIPP can achieve fast (single-pole) response regardless of the size of the storage capacitor, when both the boost and flyback parts operate in discontinuous mode. Also, both the power converters have a high DC output impedance View full abstract»

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  • Effect of dimension on characteristics of Rosen-type piezoelectric transformer

    Page(s): 1504 - 1510 vol.2
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    Characteristics of a Rosen-type piezoelectric transformer (PT) were analyzed by combining an equivalent circuit with piezoelectric equations, and the relation between the characteristics and the dimension of the PT was studied. The analyzed results showed that the voltage step-up ratio, efficiency, and power transfer per the square of input voltage depend on the ratio of length to width, lL/l W, as well as the ratio of length to thickness, lL/lT, of the PT. The calculated step-up ratio vs. load resistance curve was divided into four regions depending on the value of load resistance, and a suitable dimension of the PT was derived for each region. Then it was concluded that a wide PT has superior characteristics for a small value of load resistance and that a long PT is suitable for a large value of load resistance. The analytical results were also confirmed by experiments View full abstract»

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  • A self-tuning controller for switched reluctance machines

    Page(s): 1269 - 1275 vol.2
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    A self-tuning controller for switched reluctance machines is presented. A torque ripple minimizing controller is implemented with the on-line system identification and adaptation technique. The controller uses a nonlinear model of the machine which is updated on-line using a recursive identification algorithm. The real-time approach improves the overall robustness of the system. Experimental results are presented to validate the self-tuning algorithm View full abstract»

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  • SDI (strategic dual image) solution of PCB (printed circuit board) containing magnetic material

    Page(s): 1675 - 1680 vol.2
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    One way to control electromagnetic interference (EMI) generated on a printed circuit board (PCB) operating at high frequency is to cover the power layer by a magnetic thin film. The device modeling makes it possible to analyze electromagnetic features and then to optimize the device performances. This paper presents the finite element modeling of a 2D axisymmetric, magnetodynamic, unbounded problem composed of a PCB containing a Mn-Zn ferrite thin film. Hysteresis is taken into account in the computation. The final solution is obtained by using the strategic dual image method (SDI). The results show especially the good performances of this device configuration at high frequency, up to 1 GHz View full abstract»

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  • A multiple-winding magnetics model having directly measurable parameters

    Page(s): 1472 - 1478 vol.2
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    A general model of the multiple-winding transformer and coupled inductor is presented, in which all parameters can be directly measured. The approach is suitable for all winding geometries, and simplifying approximations can be easily made. This model can be applied in the determination of cross-regulation, current ripple and small-signal dynamics of multiple-output DC-DC power converters. An experimental four-winding flyback transformer example is investigated. Observed leakage inductance parameter measurements are interpreted physically, and are related to observed flyback converter waveforms. It is also shown that the model correctly predicts small-signal dynamics View full abstract»

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  • Non-intrinsic differential mode noise caused by ground current in an off-line power supply

    Page(s): 1131 - 1133 vol.2
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    Nonintrinsic differential-mode (DM) noise caused by ground current is common in switch-mode power supplies, but the phenomenon is first uncovered and reported in this paper. Using the zero-span mode of a spectrum analyzer allows one to investigate this mode of noise. It is found that this mode of noise is a voltage-generated noise, caused by the unbalance of the circuit. Understanding the phenomenon makes the EMI diagnosis and filter design less of a “black magic” View full abstract»

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  • A low profile type high frequency transformer using a fine grained Mn-Zn ferrite

    Page(s): 1492 - 1498 vol.2
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    A conductor-embedded-type transformer using a fine grained Mn-Zn ferrite was fabricated. The developed transformer shows a higher efficiency and a more uniform distribution of the surface temperature rise than the conventional El-core type transformer which has the same volume as the developed transformer. The high efficiency is contributed to using the fine grained Mn-Zn ferrite with low core losses at 1 MHz and also adopting the conductor-embedded-type structure, which serves the uniform flux density in the core and current density in the conductor View full abstract»

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  • High power factor correction circuit using valley charge-pumping for low cost electronic ballasts

    Page(s): 2003 - 2008 vol.2
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    A new cost-effective power factor correction (PFC) circuit, the improved valley fill (IVF) circuit combined with charge pumping capacitors (CPCs), used as an electronic ballast for fluorescent lamps is proposed. The IVF can adjust the valley voltage higher than half of the peak line voltage. The CPCs draw current from the input line to make up the current waveform during the valley interval. The measured power factor and total harmonic distortion for a prototype electronic ballast are 0.996 and 5.5%, respectively View full abstract»

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