Kazunori Hasegawa
Kyushu Institute of Technology
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Publication
Featured researches published by Kazunori Hasegawa.
IEEE Transactions on Power Electronics | 2017
Kazunori Hasegawa; Satoru Takahara; Shoji Tabata; Masanori Tsukuda; Ichiro Omura
This paper proposes a new output current measuring method using tiny printed-circuit-board (PCB) current sensors. The method will make it possible to install the PCB current sensors in an insulated-gate bipolar transistor (IGBT) module. The PCB sensor picks up a switching current flowing through an IGBT chip, and then a combination of a digital circuit based on field-programmable gate array and an integrator circuit reproduces the output current of an inverter from the switching current. A proof-of-concept experimental verification is carried out using a buck converter, which verifies that the proposed method detects a dc component of the output current as well as a ripple component although the PCB sensor is based on the so-called Rogowski coil.
IEEE Transactions on Industrial Electronics | 2016
Kazunori Hasegawa; Ichiro Omura; Shin Ichi Nishizawa
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 circuit.
international symposium on power semiconductor devices and ic's | 2015
Kenichi Yamamoto; Fumio Ichihara; Kazunori Hasegawa; Masanori Tukuda; Ichiro Omura
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.
european conference on cognitive ergonomics | 2016
Kazunori Hasegawa; Keiji Wada; Ichiro Omura
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.
Microelectronics Reliability | 2016
Kazunori Hasegawa; K. Kozuma; K. Tsuzaki; Ichiro Omura; Shin Ichi Nishizawa
Abstract DC-link capacitors are a major factor of degrading reliability of power electric converters because they usually have a shorter lifetime and higher failure rate than those of semiconductor devices or magnetic devices. Characteristics of the capacitors are usually evaluated by a single sinusoidal current waveform. However, actual current flowing out of the converter into the capacitor is a modulated square current waveform. This paper provides experimental comparison of the power loss dissipated in an aluminum electrolytic capacitor between sinusoidal and square-wave current injections. Power loss is estimated by temperature rise of the capacitor. Experimental results confirm that power losses of the square-wave current injection were always lower than those of the sinusoidal current injection by 10–20%. Moreover, the power losses of the square-wave current injection can be estimated by a synthesis of fundamental and harmonic currents based on the Fourier series expansion, which brings a high accuracy less than 1% when more than fifth harmonic current is introduced. This comparison will be useful for estimating power loss and life time of electrolytic capacitors.
Microelectronics Reliability | 2018
Masanori Tsukuda; Seiya Abe; Kazunori Hasegawa; Tamotsu Ninomiya; Ichiro Omura
Abstract In this paper, we propose the criteria of bias voltage from parasitic capacitance and demonstrate the criteria in an experiment with the present IGBT. The bias voltage criteria are theoretically predicted for the new generation IGBT based on the scaling principle. For safe switching, the required gate voltage bias is predicted to be −1.2 V or less for the present IGBTs and − 6 V or less is required to completely cancel the gate noise voltage. From the IGBT design, the bias voltage of scaling IGBT requires −2 V to completely cancel the gate noise voltage.
Microelectronics Reliability | 2018
Bat-Otgon Bat-Ochir; Battuvshin Bayarkhuu; Kazunori Hasegawa; Masanori Tsukuda; Bayasgalan Dugarjav; Ichiro Omura
Abstract Health monitoring of the power conversion system is very important. Therefore, we developed a new method for measuring IGBT currents and reproducing average load current to monitor IGBTs. This method was successfully tested on an experimental setup which showed that the tiny PCB sensors can be integrated into intelligent power modules. We proposed an inexpensive analogue circuit which is suitable for capturing current information from a tiny PCB Rogowski coil. The sensors and corresponding circuit can be embedded into an Intelligent Power Module. The method was named “Envelop tracking” as it simultaneously measures the currents of the high and low side switches of a power converter and reproduces the upper and lower edges of the load current which can be averaged by further digital processing.
Microelectronics Reliability | 2018
Kazunori Hasegawa; Shin Ichi Nishizawa; Ichiro Omura
Abstract Condition monitoring plays an important role in estimating health condition of capacitors because the ageing of the capacitors is usually accompanied by an increase in equivalent series resistance (ESR) and a decrease in capacitance. Either capacitance or ESR cannot be a unique indicator of the lifetime of capacitors in some cases. This paper presents a condition monitoring method of a dc-link capacitor used in a three-phase PWM inverter with a front-end diode rectifier intended for motor drives. The monitoring method extracts both the ESR and capacitance of a capacitor under test from the actual ripple current and voltage without disconnecting the capacitor nor injecting an additional current. The monitoring method, therefore, can be implemented online. Experimental results verify that the monitoring method independently obtains the ESR and capacitance changes of the capacitor under test. This contributes to accurate lifetime estimation of dc-link capacitors.
Microelectronics Reliability | 2018
Kazunori Hasegawa; K. Tsuzaki; Shin Ichi Nishizawa
Abstract Attention has been paid to reliability-related issues for dc-link capacitors such as monitoring methods, power-loss estimation, and ageing tests. The degradation of the capacitors depends on their operating condition including temperature, ripple current, and dc-bias voltage, which has a strong influence on failures as well. In design stages of power converters, it is desirable to know the relation between the degradation and electrolytic parameters. This paper makes an intensive discussion on the voltage dependence of the degradation of a small aluminum electrolytic capacitor with an ageing test and a leakage-current measurement. The ageing test reveals that a higher dc-bias voltage brings a faster increase in ESR but results in a slower drop in capacitance in a range within the rated voltage. This result implies that either capacitance or ESR cannot be a unique indicator of the lifetime. Attention should be paid both to the ESR and to the capacitance when one monitors the capacitor condition. On the other hand, more than the rated voltage leads a rapid degradation of the capacitor, which can be confirmed by a leakage-current measurement instead of the ageing test.
international symposium on power semiconductor devices and ic's | 2017
Shoji Tabata; Kazunori Hasegawa; Masanori Tsukuda; Ichiro Omura
This paper proposes a new power module concept that integrates output current measurement function to make inverters compact. The current measurement function is realized by tiny printed-circuit-board (PCB) Rogowski coils. The PCB Rogowski coil picks up a switching current flowing through an IGBT chip, and then a combination of a digital circuit based on a field-programmable-gate-array (FPGA) and an integrator circuit reproduces the output current of the inverter from the switching current. A major concern of the new power module is the effect of reverse recovery current of free-wheeling diodes because the reverse recovery current is superimposed on the switching current. This paper proposes a mitigating method of the reverse recovery current.
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National Institute of Advanced Industrial Science and Technology
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