1,721,067 research outputs found
DESIGN OF A HIGHLY STABLE ELECTROMAGNET POWER-SUPPLY
No full textA method for designing a highly stable electromagnet power supply combining the 12-pulse phase-controlled rectifier (PCR), passive filter, and transformed active filter is investigated. The PCR system is analyzed and passive filter parameters are designed from this analysis. A phase-locked voltage control circuit with a fast dynamic characteristic is analyzed and an optimal constant proportional-integral and measurable variable feedback plus feedforward (PIMF) current controller is designed using a time-weighted quadratic performance index. It is also shown via experimental results that the proposed design method gives good performance.X116sciescopu
OPTIMAL-REGULATORS USING TIME-WEIGHTED QUADRATIC PERFORMANCE INDEX WITH PRESPECIFIED CLOSED-LOOP EIGENVALUES
No full textX115sciescopu
Single-stage asymmetrical PWM AC-DC converter with high power factor
No full textThe proposed converter combines the power factor correction stage and them inverter stage to convert the DC-link voltage to a high-frequency unidirectional alternating voltage, which is fed to a high-frequency transformer through a resonant circuit. Experimental results for a 70W converter at a constant switching frequency of 100 kHz are obtained to show the performance of the proposed converter.X1110sciescopu
Novel PWM line conditioner with fast output voltage control
No full textA novel pulse-width modulated (PWM) line conditioner with fast output voltage control is proposed. The line conditioner is made up of a PWM AC chopper and a transformer for series voltage compensation. In the PWM AC chopper, a proper switching operation for solving the commutation problem is achieved. Power semiconductor modules which are commercially available can be used in this circuit and regenerative DC snubbers are attached directly to power semiconductor modules to absorb the energy stored in line stray inductance. These regenerative DC snubbers have a very simple structure consisting of a capacitor only with no discharging resistors or complicated regenerative circuit for snubber energy. Therefore the proposed AC chopper gives high efficiency and high reliability. The output voltage of the line conditioner is controlled using rapid sensing of the output voltage. The optimal gains of the controller giving an output with small overshoot and adequate damping are designed using the time-weighted quadratic performance index. It is also shown using simulation and experimental results that the proposed line conditioner gives good dynamic and steady state performances with high quality output voltage.X1112sciescopu
Unity power factor ZVS AC-to-DC converters with an active filter
No full textUnity power factor zero-voltage-switched ac-to-dc converters with an active filter are proposed, The line voltage is supplied to ac-to-dc converters through the rectifier circuit with an input filter, to reduce high-frequency ripple components, The line current is almost synchronized to the line voltage, due to the low impedance of the input filter. The forward zero-voltage-switched multiresonant converters (ZVS-MRC's) are utilized for high-frequency operation and lossless switching, An active filter is introduced to minimize the twice line-frequency ripple component of the output voltage without large-size passive filters, Experimental results show that the proposed scheme gives good steady-state performances of the ac-to-dc converters.X114sciescopu
Active-clamped ripple-free DC/DC converter using an input-output coupled inductor
No full textA new input-output coupled inductor (100) is proposed for reducing current ripples and magnetic components. Moreover, a current-source-type circuit using active-clamp mechanism and a current doubler with synchronous rectifier are presented to achieve high efficiency in low input-output voltage applications. The configuration of the 100 is realized by three windings on a common core, and has the properties of an input inductor at the input-side and two output inductors at the output-side. An active clamped ripple-free dc-dc converter using the proposed 100 is analyzed in detail and optimized for high power efficiency. Experimental results for 80 W (5 V/16 A) at a constant switching frequency of 100 kHz are obtained to show the performance of the proposed converter.X1123sciescopu
A Simple Sustain Power Conversion Scheme for AC Plasma Display Panel
No full textA simple sustain power conversion scheme for a plasma display panel (PDP) is proposed. The proposed scheme is comprised of two-stage power conversion. The power factor correction circuit converts ac line voltage into dc-link voltage and provides a high power factor while maintaining a constant dc-link voltage. The proposed sustain driver converts the dc-link voltage into the sinusoidal voltage generated by the resonant inverter. Since a sinusoidal voltage is applied to the panel, the charging or discharging surge current can be eliminated without using an energy recovery circuit. Also, the soft switching of the switching devices can be achieved by the resonant tank. Thus, the proposed sustain driver features fewer components and lower electromagnetic interference noise. Moreover, since the proposed sustain driver is implemented with a transformer, the dc-dc converter that is used to generate sustain power in the conventional sustain power conversion scheme can be eliminated. Therefore, the proposed sustain power conversion scheme features a simple structure and low cost. The operation principle and analysis of the proposed circuit is presented in detail. The performance of a 32-inch ac PDP equipped with the proposed driving scheme is investigated. The luminance efficacy of this scheme is over 10% better than that obtained by the conventional sustain driving scheme.X110sciescopu
A Cost-Effective Sustain Power Conversion Scheme for Plasma Display Panels
No full textThis paper presents a cost-effective sustain power conversion scheme for the plasma display panel (PDP). A new energy-recovery (ER) circuit is proposed for a low-cost sustain driver. As a parallel-resonant type ER circuit, it can recover the energy stored in the PDP without the interconnection of the sustaining and scanning electrodes. It has a simple structure and fewer power devices, providing a lower cost of production. In addition, a high efficiency sustain power supply is proposed to provide a constant sustain voltage for the sustain driver. It achieves zero-current turn-off of the output diode, alleviating the diode reverse-recovery problems. The sustain power efficiency is increased by reducing the switching power loss. Therefore, the cost and power consumption of the PDP can be improved. The proposed circuits are theoretically analyzed in detail. The experimental results based on a 32-in PDP are presented to confirm the validity of the proposed circuits.X111sciescopu
An effective software implementation of the space-vector modulation
No full textAn effective software implementation of the space-vector modulation (SVM) on the rotating d-q frame is proposed. The conventional SVM algorithm requires complex computations, such as square root and arctangent. The SVM algorithm is further developed to determine directly conduction times of switches without requiring complex computations.X1128sciescopu
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