1,721,051 research outputs found
Applying Coupled Inductors to the Clamped-Resonant Interleaved Boost Converter
No full textThis paper investigates the possibility to use coupled inductors in the DC-DC converter topology called Clamped-Resonant Interleaved Boost converter (CRIB). Such topology employs a resonant L-C tank connected between the switch drain terminals to achieve zero-voltage turn-on and turn-off of both switches, as well as zero-current turn-off for the rectifier diodes, independently of the load current. Moreover, no-load operation is demonstrated providing the voltage gain is higher than a minimum value. The converter analysis and proposed design criteria were verified by an experimental prototype rated at 42 - 54 V to 400 V - 300 W, showing a very good efficiency in the whole input voltage range. Performance comparison with the same topology adopting separated input inductors is included as well
A Fast On-state Voltage Measurement Circuit for Power Devices Characterization
No full textThe precise measurement of the on-state voltage of power devices working in real operating conditions is the key for their characterization as well as health monitoring. This letter proposes a new on-state voltage measurement circuit featuring very high bandwidth and accuracy. An auxiliary circuitry allows to decouple the measurement system reference potential from the noisy device-under-test environment. DC, AC, and dynamic performance have been validated from measurements on a prototype
Extended Analysis of The Asymmetrical Half-Bridge Flyback Converter
No full textIsolated, Zero-Voltage-Switching (ZVS) dc-dc converter topologies represent attractive solutions in the continuous run towards higher switching frequencies, allowing more compact power supplies. Among them, the Asymmetrical Half-Bridge Flyback Converter (AHBFC) represents an interesting option, featuring simple duty-cycle control at constant switching frequency, as opposed to the popular LLC converter. The majority of papers dealing with this topology consider an approximated voltage gain similar to that of an isolated Buck converter operating in CCM, i.e. proportional to the duty-cycle, and, practically, load independent. On the contrary, the true voltage gain is non monotonic at high duty-cycle values. Anytime the converter is designed for a resonant operation, as is advisable to eliminate any reverse recovery problem of the rectifier diode, the voltage gain not only increases, but becomes a function of the switching frequency. This paper investigates the converter's voltage gain in detail, deriving a theoretical framework capable of capturing its real behavior and dependencies. The proposed analytical model has been verified through simulations as well as experimental measurements taken on a 160 W prototype working at 400 kHz
Line-frequency commutated rectifier complying with IEC 1000-3-2 standards
No full textConsumer and household appliances require cheap ac/dc power supplies complying with EMC standards. The commonly employed passive solutions are bulky and do not provide output voltage stabilization. Active solutions, based on PFC's with high-frequency switching, provide compactness and regulation capability, but are generally expensive due to the need for fast-recovery diodes and complex EMI filters. This paper presents a high power factor rectifier, based on a modified conventional rectifier with passive L-C filter, which improves both the harmonic content of the input current and the power factor, by means of a low frequency commutated switch and a small line-frequency transformer, and allows to comply with IEC 1000-3-2 standard with reduced overall inductive components' volume
Clamped-resonant interleaved boost converter: Analysis and design
No full textThis paper presents the detailed analysis and design of a soft-switching DC-DC converter called clamped-resonant interleaved boost converter (CRIB). This topology, thanks to a resonant L-C tank connected between the drain terminals of the switches of two interleaved boost cells, achieves zero-voltage and zero current commutations of all devices, independently of the load current, with a reduced dv/dt across the switches, making the converter suitable for high-frequency operation. Moreover, a proper no-load operation is proved, whenever the minimum voltage gain is higher than a given threshold. Differently from previous works on current-fed resonant converters, the presented theoretical analysis includes the effect of the input filter inductors, allowing to derive a simple design procedure to meet the given specifications. According to the outlined design steps, an experimental prototype was built, rated at 42~54 V to 400 V~300 W. Measurements confirm the theoretical predictions, showing an efficiency above 96% at the nominal power in the whole input voltage range. Finally, the possibility to reduce the overall magnetic volume by coupling the two input inductors is demonstrated
Ruprecht Potsch, Frammenti dell' antico Fluegelaltar della chiesa di S.M.Nascente di Pieve di Cadore
No full textConducted EMI issues in a Boost PFC design
No full textThe paper presents the results of an experimental activity concerned with the development of a 600 W Boost Power Factor Corrector (PFC) complying with the EMC standards for conducted EMI in the 150 kHz-30 MHz range. In order to accomplish this task, different circuit design and layout solutions are taken into account and their effect on the conducted EMI behavior of the converter is experimentally evaluated. Common-mode and differential-mode switching noise, together with input filters' design and topology and with the PCB layout (in terms of track length and spacing, ground and shielding planes etc.) are the key aspects which have been analyzed. In particular, the paper reports the conducted EMI measurements for different filter capacitor placements and values, for different power switch drive circuits together with several other provisions which have turned out to be decisive in the reduction of the generated EMI
Low-loss high-power-factor flyback rectifier suitable for smart power integration
No full textA low-loss, high-power-factor flyback rectifier is presented, which is designed as a possible application for a new type of smart power integrated circuit. This is going to be manufactured by ST Microelectronics using the VIPower M3 technology and will include on the same silicon chip both control circuitry and an emitter switching power device. In order to avoid dangerous interactions between power and control part of the integrated circuit, it is necessary to control the rate of change of the power device voltage at turn-off. Accordingly, a lossless passive snubber was added to the conventional converter topology. The snubber also limits the voltage spikes across the power device, due to the transformer leakage inductance, and reduces the electromagnetic noise generation. A modified non-linear carrier control is considered which, thanks to the integration of the switch current signal, ensures high power factor and inherent noise immunity together with a simple control implementation (no need of input voltage sensing, multiplier and current error amplifier). A 200 W converter prototype was tested in order to evaluate the achievable performance
The Asymmetrical Half-Bridge Flyback Converter: A Reexamination
No full textIsolated Zero-Voltage-Switching (ZVS) dc-dc converter topologies are attractive solutions in the continuous ride toward higher switching frequencies, allowing more compact power supplies. Among them, the Asymmetrical Half-Bridge Flyback Converter (AHBFC) represents an interesting solution, featuring a simple duty-cycle control at a constant switching frequency, as opposed to the popular LLC converter. The majority of the papers dealing with this topology, present an approximated voltage gain which is similar to an isolated Buck converter, i.e. proportional to the duty-cycle. However, when the converter is designed for a resonant operation, so as to eliminate any reverse recovery problem of the rectifier diode, its voltage gain can be quite different, becoming non monotonic and a function of the switching frequency. This paper investigates this aspect, deriving a theoretical framework capable of capturing its real voltage gain behavior. The proposed analytical model has been verified through simulations as well as experimental measurements taken on a 160W prototype working at 400kHz
aiuto di A. Haller,scultura lignea raffigurante sant' Antonio Abate, chiesa di santa Fosca a Selva di Cadore
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