Mutual Inductance Measurement for Power Device Package Using Time Domain Reflectometry

Stray inductance inside power device package will be a constraint on improvement of power density as well as switching frequency in power converters because the converters will suffer from electromagnetic interference (EMI)-related problems. This paper proposes a measurement method of mutual inductance for power device packages using time domain reflectometry. The method is characterized by introducing four-terminal measurement that distinguishes self and mutual inductances among collector, emitter, and gate terminals. A measurement fixture for a discrete IGBT is designed, constructed, and tested to ensure repeatability of the proposed method. Experimental results verifies the viability of the proposed method.2016 IEEE Energy Conversion Congress and Exposition (ECCE), 18-22 September 2016, Milwaukee, WI, US

A New Evaluation Circuit with a Low-Voltage Inverter Intended for Capacitors Used in a High-power Three-phase Inverter

DC-link capacitors in power electronic converters are a major constraint on improvement of power density as well as reliability. Evaluation of the dc-link capacitors in terms of power loss, ageing, and failure rate will play an important role in design stages of the next-generation power converters. This paper proposes a new evaluation circuit for dc-link capacitors used in a high-power three-phase inverter, which is intended for testing power loss, failure rate, ageing, and so on. The evaluation circuit produces a practical ripple current waveform and a dc bias voltage into a capacitor under test, in which the ripple current is equivalent to that generated by the three-phase inverter on the dc link. The evaluation circuit employs a full-scale current-rating and downscaled voltage-rating inverter for producing the ripple current, so that the power rating of the evaluation circuit is much smaller than that of a full-scale current rating and full-scale voltage rating inverter.2016 IEEE Applied Power Electronics Conference and Exposition (APEC 2016), March 20-24, 2016, Long Beach, California, US

Design and Analysis of a New Evaluation Circuit for Capacitors Used in a High-Power Three-Phase Inverter

DC-link capacitors in power electronic converters are a major constraint on improvement of power density as well as reliability. Evaluation of the dc-link capacitors in terms of power loss, ageing, and failure rate will play an important role in design stages of the next-generation power converters. This paper proposes a new evaluation circuit for dc-link capacitors used in a high-power three-phase inverter, which is intended for testing power loss, failure rate, ageing, and so on. The evaluation circuit produces a practical ripple current waveform and a dc bias voltage into a capacitor under test, in which the ripple current is equivalent to that generated by the three-phase inverter on the dc link. The evaluation circuit employs a full-scale current-rating and downscaled voltage-rating inverter for producing the ripple current, so that the power rating of the evaluation circuit is much smaller than that of a full-scale current-rating and full-scale voltage-rating inverter. Theoretical analysis and simulated results verify the effectiveness of new evaluation circui

A New Evaluation Circuit with a Low-Voltage Inverter Intended for Capacitors Used in a High-power Three-phase Inverter

016 IEEE Applied Power Electronics Conference and Exposition (APEC 2016), March 20-24, 2016, Long Beach, California, USADC-link capacitors in power electronic converters are a major constraint on improvement of power density as well as reliability. Evaluation of the dc-link capacitors in terms of power loss, ageing, and failure rate will play an important role in design stages of the next-generation power converters. This paper proposes a new evaluation circuit for dc-link capacitors used in a high-power three-phase inverter, which is intended for testing power loss, failure rate, ageing, and so on. The evaluation circuit produces a practical ripple current waveform and a dc bias voltage into a capacitor under test, in which the ripple current is equivalent to that generated by the three-phase inverter on the dc link. The evaluation circuit employs a full-scale current-rating and downscaled voltage-rating inverter for producing the ripple current, so that the power rating of the evaluation circuit is much smaller than that of a full-scale current rating and full-scale voltage rating inverter

NADase as a target molecule of in vivo suppression of the toxicity in the invasive M-1 group A Streptococcal isolates

<p>Abstract</p> <p>Background</p> <p>NAD-glycohydrolase (NADase) secreted by M-1 group A streptococcal (GAS) isolates are suspected as one of the virulence factors to cause severe invasive disease including streptococcal toxic shock-like syndrome (STSS). M-1 GAS strains were divided into three groups based on NADase activity: high activity, low activity and no activity in our previous report.</p> <p>Results</p> <p>The representative high activity isolates taken from STSS patients showed higher virulence compared with isolates from the low activity group, when used to infect mice. The knockout mutant of the <it>nga </it>gene, which encodes NADase also showed reduced virulence in a mouse infection study. The cloned <it>nga </it>gene was able to significantly complement the lost virulence. In addition, the solution containing purified recombinant IFS, which is an inhibitor of NADase, partially rescued mice infected with <it>S. pyogenes</it>.</p> <p>Conclusions</p> <p>These results indicate that NADase is important for the virulence of <it>S. pyogenes </it>in vivo and is the potential target to suppress the virulence.</p

Calorimetric Power-Loss Measurement of a High-Power Film Capacitor with Actual Ripple Current Generated by a PWM Inverter

This paper proposes a calorimetric power-loss measurement method suitable for a high-power film capacitor used in the dc link of a high-power three-phase PWM inverter. The measurement method is characterized by using a thermally-insulated container and an evaluation circuit for dc-link capacitors. Introduction of the thermally-insulated container achieves an accurate power loss measurement that is of the order of 1 W. The evaluation circuit provides the equivalent ripple current waveform and dc-bias voltage to those of the high-power three-phase PWM inverter although its power rating is 1/24 of the high-power inverter. This combination makes it possible to measure the power loss of the capacitor under actual voltage/current condition at low cost. Experimental results obtained from a 1200-V 210-kVA system verify the viability and effectiveness of the proposed method.The Tenth Annual IEEE Energy Conversion Congress and Exposition (ECCE 2018), September 23–27, 2018, Portland, Oregon, USA

60 GHz Wireless Signal Transmitting Gate Driver for IGBT

This paper shows the very first demonstration result of wireless IGBT gate drive using with 60 GHz wireless module with sufficient “real-time” control with 100 ns-level time delay with small fluctuation of the delay.2015 IEEE 27th International Symposium on Power Semiconductor Devices & IC\u27s (ISPSD 2015), May 10-14, 2015, Hong Kong, Chin

Finite-temperature Mott transitions in multi-orbital Hubbard model

We investigate the Mott transitions in the multi-orbital Hubbard model at half-filling by means of the self-energy functional approach. The phase diagrams are obtained at finite temperatures for the Hubbard model with up to four-fold degenerate bands. We discuss how the first-order Mott transition points $U_{c1}$ and $U_{c2}$ as well as the critical temperature $T_c$ depend on the orbital degeneracy. It is elucidated that enhanced orbital fluctuations play a key role to control the Mott transitions in the multi-orbital Hubbard model.Comment: 8 pages, 7 figure

An Evaluation Circuit for DC-Link Capacitors used in a Single-Phase PWM Inverter

High-power conversion systems are based not only on three-phase inverters but also on single-phase inverters because modular multilevel cascade converters (MMCC) consist of half- or full-bridge single-phase converters. Their DC-link capacitors are a major constraint on the improvement of power density as well as of reliability. Evaluation of dc-link capacitors in terms of power loss, ageing, and failure rate will play an important role in the next-generation power converters. This paper presents an evaluation circuit for dc-link capacitors used in a high-power single-phase PWM inverter. The evaluation circuit produces a practical ripple current waveform and a dc bias voltage into a capacitor under test with a downscaled voltage-rating inverter, which is equivalent to those of the full-scale inverter. Theoretical analysis and experimental results verify the effectiveness of the evaluation circuitPCIM Europe 2017, 16 – 18 May, 2017, Nuremberg, German