研究者詳細 - 平木　英治

論文 - 平木　英治

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Analytical Investigation on Design Instruction to Avoid Oscillatory False Triggering of Fast Switching SiC-MOSFETs

Yusuke Sugihara, Kimihiro Nanamori, Seiya Ishiwaki, Yuma Hayashi, Kyota Aikawa, Kazuhiro Umetani, Eiji Hiraki, Masayoshi Yamamoto

2017 IEEE ENERGY CONVERSION CONGRESS AND EXPOSITION (ECCE) 5113 - 5118 2017年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

SiC-MOSFETs have attracting increasing attention because of their outstanding characteristics that contributes to high efficiency and high power density of power converters. However, compared to conventional Si-IGBTs, SiC-MOSFETs are susceptible to false triggering, because they tend to generate large switching noise due to ultrafast switching capability and have a lower threshold voltage in high temperature operation. Particularly, disastrous oscillation of repetitive false triggering can occur after a fast turn-off, which is the severe issue for practical application of SiC-MOSFETs. The purpose of this paper is to give an instruction to avoid this phenomenon. This paper hypothesized that the repetitive false triggering is the parasitic oscillation caused by parasitic capacitance of SiC-MOSFET, and parasitic inductance of wiring. Based on this hypothesis, this paper analyzed the oscillatory condition of the parasitic oscillator to propose a design instruction to avoid the oscillatory false triggering. The result revealed that the parasitic inductance of the gate, drain, and source wiring should be designed so that the resonance frequency of the parasitic LC resonator in the gating circuit is far apart from that of the power circuit. This paper also presents experimental results that support appropriateness of the proposed design instruction.

Evaluation of Impact of Parasitic Magnetic Coupling in PCB Layout on Common Source Inductance of Surface Mounted Package

Ryunosuke Matsumoto, Kyota Aikawa, Akihiro Konishi, Kazuhiro Umetami, Eiji Hiraki

2017 IEEE 12TH INTERNATIONAL CONFERENCE ON POWER ELECTRONICS AND DRIVE SYSTEMS (PEDS) 559 - 566 2017年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Recently, the common source inductance (CSI) is regarded as one of the most important obstacles for achieving ultrafast switching of switching converters. The CSI is pointed out to be a major cause of deterioration of the switching speed and false triggering. Therefore, many design instructions of next generation switching devices, such as GaN-FETs and SiC-MOSFETs, have pointed out the necessity to reduce the CSI. Certainly, many of the next generation switching devices are provided in surface mount packages in order to enable PCB designers to minimize the CSI by eliminating the common source path. However, the parasitic magnetic coupling between the gating circuit and the power circuit may still add the CSI, although preceding studies have scarcely reported how greatly the PCB layout can affect the CSI and the switching waveforms. This paper experimentally evaluated the impact of the parasitic magnetic coupling of the PCB layout on the CSI of the surface mount package and on the switching waveforms. As a result, the parasitic magnetic coupling was found to cause the major difference in the CSI. In addition, large difference in the turn-off switching waveforms was found to be caused by the difference in the magnetic coupling. The reason is also analyzed and discussed in this paper, suggesting importance of appropriate design of the parasitic magnetic coupling in the PCB layout.

Measurement of the Common Source Inductance of Typical Switching Device Packages

Kyota Aikawa, Tomohumi Shiida, Ryunosuke Matsumoto, Kazuhiro Umetani, Eiji Hiraki

2017 IEEE 3RD INTERNATIONAL FUTURE ENERGY ELECTRONICS CONFERENCE AND ECCE ASIA (IFEEC 2017-ECCE ASIA) 1172 - 1177 2017年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

The common source inductance is one of the major causes of deterioration of the switching speed and susceptibility of the false triggering for semiconductor switching devices. Practical design of this inductance requires selection of an appropriate semiconductor package because this inductance is greatly dependent on the physical package structure. However, few studies have reported a list of the common source inductance of commercially available packages. In order to list and compare the common source inductance among typical semiconductor packages, this paper carried out measurement of this inductance of actual switching devices mounted on experimental PCBs. This paper employed a recently proposed straightforward measurement technique directly applicable to switching devices mounted on PCBs. As a result, a basic database of the common source inductance of typical packages was presented. The common source inductance was found to be determined mainly by the package type. However, in TO-247 and TO-220 packages, approximately one-third of the total common source inductance was found to possibly vary among the switching devices of the same package due to the dependence on the current rating. Investigation of the physical package structure implied that this dependence was caused by the stray inductance of the bonding wires connecting the semiconductor chip to the source terminal.

Elucidation of Quasi-Duality between Series-Series and Series-Parallel Topologies of Resonant Inductive Coupling Wireless Power Transfer Systems

Masataka Ishihara, Kazuhiro Umetani, Eiji Hiraki

2017 IEEE 12TH INTERNATIONAL CONFERENCE ON POWER ELECTRONICS AND DRIVE SYSTEMS (PEDS) 674 - 679 2017年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Series-Series (SS) and Series-Parallel (SP) topologies are widely utilized in practical resonant inductive coupling wireless power transfer (RIC-WPT) systems owing to their simple circuit configurations. Conventionally, design optimization of the circuit parameters of these topologies were investigated separately, because these topologies are expressed by different equivalent circuits. However, analysis of these equivalent circuits is generally complicated due to the multiple resonant modes contained in the operation, which may cause difficulty in comparing the performance between the SS and SP topologies after design optimization of these topologies. This difficulty may prevent elucidating the methodology to select an appropriate topology that offers better output power or efficiency after design optimization. The purpose of this paper is to suggest a selection methodology of the SS and SP topologies by elucidating a novel insight that these topologies have the quasi-duality relation, in which the SP topology works approximately as the dual of the SS topology. This insight enables to share the analysis results between the topologies. As a result, both of these topologies were found to be expressed by a same novel equivalent circuit. Furthermore, the only difference between the SS and SP topologies were found to be the equivalent load resistance of this equivalent circuit, thus reducing the topology selection into selection of preferable load resistance. The appropriateness of the quasi-duality relation and the resultant equivalent circuit was successfully confirmed by the simulation and the experiment.

Soft-switching Technique Applicable to Capacitive Load for Resonant Inverter of Plasma Generator

Koji Itakura, Hiroaki Kakemizu, Hiroki Nakaido, Kazuhiro Umetani, Eiji Hiraki, Tatsuya Ikenari, Shingo Kawano

IECON 2017 - 43RD ANNUAL CONFERENCE OF THE IEEE INDUSTRIAL ELECTRONICS SOCIETY 1556 - 1562 2017年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Recently, resonant inverters have been employed to generate high voltage high frequency AC power for plasma generator of the semiconductor processing equipment. This inverter is beneficial in low switching loss owing to its natural soft switching capability under inductive load impedance. Generally, the resonant inverter for plasma generator is designed to have inductive load using an impedance matching circuit that interfaces the inverter and the plasma reactor. However, the load impedance often fluctuates according to the state of the plasma, momentarily causing the capacitive load impedance. In this case, the inverter is generally controlled to restrict the output power for circuit protection from excessive switching loss, although this will result in unstable plasma, deteriorating the quality of the semiconductor processing. This paper addressed this difficulty by applying a soft switching technique to the resonant inverter. This soft-switching technique can be utilized regardless to the capacitive or inductive load. Experiment was carried out to evaluate the effectiveness of the proposed technique. As a result, the effective reduction of the switching loss was successfully verified even under the capacitive load impedance.

Simple Self-Driven Synchronous Rectifier for Resonant Inductive Coupling Wireless Power Transfer

Takahiro Koyama, Toru Honjo, Masataka Ishihara, Kazuhiro Umetani, Eiji Hiraki

2017 IEEE INTERNATIONAL TELECOMMUNICATIONS ENERGY CONFERENCE (INTELEC) 363 - 368 2017年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Resonant inductive coupling wireless power transfer (RIC-WPT) is attracting attention as a convenient power supply method to small mobile apparatus. The efficiency and the power transfer capability of RIC-WPT has been known to be profoundly dependent on the quality factor of the receiving resonator. However, the quality factor of the receiving resonator tends to be deteriorated because of the conduction loss at the diode rectifier, particularly for low output voltage applications. In order to improve the efficiency and the power transfer capability, this paper propose a novel simple synchronous rectifier, which can reduce the conduction loss. The proposed rectifier has simple circuit configuration, which contributes to straightforward application to the wireless power transfer to small mobile apparatus with limited installation space. Experiment was carried out to verify the operation principle of the proposed rectifier. As a result, the proposed rectifier revealed successful suppression of the conduction loss. In addition, the experimental wireless power transfer system verified successful improvement in the rectification efficiency, supporting usefulness of the proposed rectifier for practical applications of the RIC-WPT for small mobile apparatus.

Simple Analytical Derivation of Magnetic Flux Profile Eliminating Source Current Ripple and Torque Ripple of Switched Reluctance Motors for Electric Vehicle Propulsion

Takayuki Kusumi, Takuto Hara, Kazuhiro Umetani, Eiji Hiraki

2017 THIRTY SECOND ANNUAL IEEE APPLIED POWER ELECTRONICS CONFERENCE AND EXPOSITION (APEC) 3142 - 3149 2017年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

This paper proposes a simple control technique for switched reluctance motors to eliminate both the source current ripple and the torque ripple simultaneously. The proposed control is a current tracking control based on a pre-computed magnetic flux profile. This profile is derived using a simple analytical SRM model without the magnetic saturation. Conventionally, the magnetic saturation is commonly utilized for limiting excessive magnetic flux induction to improve the torque output. However, in the proposed control, the magnetic flux profile is utilized for limiting the magnetic flux by control. By controlling without the magnetic saturation, elimination of the source current ripple and the torque ripple can be achieved regardless to the output power. Along with theoretical derivation of the magnetic flux profile, an experiment is carried out to evaluate the proposed control. The results revealed suppression of the source current ripple and the torque ripple simultaneously in comparison with the conventional square-wave current control.

Quasi-duality between SS and SP topologies of basic electric-field coupling wireless power transfer system

M. Ishihara, K. Umetani, H. Umegami, E. Hiraki, M. Yamamoto

Electronics Letters 52 ( 25 ) 2057 - 2059 2016年12月

掲載種別：研究論文（学術雑誌）

Series-series (SS) topology and series-parallel (SP) topology of the electric-field coupling wireless power transfer system are widely utilised for practical applications. However, selecting the appropriate circuit topology, which maximise the output power by design optimisation, is often difficult, because these circuit topologies are generally analysed using different circuit models. This difficulty by analysing novel equivalent circuits for SS and SP topologies is addressed. As a result, the output power of SP topology is found to be approximated by that in SS topology with transformed load impedance. This result can offer a simple strategy for topology selection as well as design optimisation.

DOI： 10.1049/el.2016.1253

A design guideline of parasitic inductance for preventing oscillatory false triggering of fast switching GaN-FET

Kazuhiro Umetani, Keisuke Yagyu, Eiji Hiraki

IEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING 11 S84 - S90 2016年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY

Gallium nitride field-effect transistors (GaN-FETs) are attractive devices because of its low on-state resistance and fast switching capability. However, they can suffer from false triggering caused by fast switching. Particularly, a disastrous oscillation of repetitive false triggering can occur after a turn-off, which may deteriorate the reliability of power converters. To address this issue, we give a design guideline to prevent this phenomenon. We analyze a simple circuit model to derive the condition of occurrence of this phenomenon, which is then verified experimentally. Results show that the parasitic inductance of the gating circuit, L-g, and that of the decoupling circuit, L-d, should be designed so that the LC resonance frequency of L-g and the gate-source capacitance of the GaN-FET does not coincide with that of L-d and the drain-source capacitance, respectively. (c) 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

DOI： 10.1002/tee.22339

A Simple Behavior Model for Switched Reluctance Motors Based on Magnetic Energy

Takuto Hara, Takayuki Kusumi, Kazuhiro Umetani, Eiji Hiraki

2016 IEEE 8TH INTERNATIONAL POWER ELECTRONICS AND MOTION CONTROL CONFERENCE (IPEMC-ECCE ASIA) 109 - 115 2016年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

A number of analytical models for switched reluctance motors have been proposed to promote development of control techniques that can alleviate the torque and source current ripples. However, these models can suffer from a large database of the nonlinearity as well as complicated derivation process of the torque and the voltage-current relation. The purpose of this paper is to propose a simple practical behavior model with small database and straightforward derivation of the torque and the voltage-current relation. The proposed model has a simple database of the magnetic energy as a matrix. The flux linkage and the electrical angle are chosen as the state variables. Along with theoretical formulation of the model, this paper presents a practical method of the model construction. In addition, experiments successfully predicted both torque and current waveforms, supporting appropriateness of the proposed model.

Lagrangian Derivation and Analysis of a Simple Equivalent Circuit Model of Wireless Power Transfer System with Dual Transmitting Resonators

Takahiro Koyama, Toru Honjo, Kazuhiro Umetani, Eiji Hiraki

2016 18TH EUROPEAN CONFERENCE ON POWER ELECTRONICS AND APPLICATIONS (EPE'16 ECCE EUROPE) 2016年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

This paper proposes a novel analysis method for the dual transmitting resonators wireless power transfer (DTR-WPT) system. The DTR-WPT is attractive for its higher efficiency and greater power transfer capability compared with the conventional single transmitting resonator wireless power transfer (STR-WPT) system. However, analytical understanding of the DTR-WPT is difficult due to its complicated operating principle caused by two transmitting resonators and a receiving resonator, which are all magnetically coupled each other. Therefore, practical applications of the DTR-WPT may be hindered by difficulty in establishing a design optimization method and a control scheme.This difficulty is addressed in this paper by proposing a novel simple equivalent circuit model of the DTR-WPT. Lagrangian dynamics is employed to derive this model. Brief analysis of this model showed improvement in the efficiency and the power transfer capability by the DTR-WPT compared with the conventional STR-WPT. In addition, the power transfer of the DTR-WPT system was found to be expressed by the same equivalent circuit model as the STR-WPT system. Therefore, similar design optimization methods and similar control schemes as for the STR-WPT are applicable to the DTR-WPT. Along with the theory, this paper presents experiments that verified appropriateness of the proposed model as well as the analysis results based on this model.

Simple Control Technique to Eliminate Source Current Ripple and Torque Ripple of Switched Reluctance Motors for Electric Vehicle Propulsion

Takayuki Kusumi, Takuto Hara, Kazuhiro Umetani, Eiji Hiraki

PROCEEDINGS OF THE IECON 2016 - 42ND ANNUAL CONFERENCE OF THE IEEE INDUSTRIAL ELECTRONICS SOCIETY 1876 - 1881 2016年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Switched reluctance motors (SRMs) are expected to be applied to propulsion systems of electric vehicles for their robust mechanical construction and cost-effectiveness. On the other hand, their large source current ripple and large torque ripple are main obstacles in practical applications of SRMs to vehicle propulsion. Certainly, a number of studies have been dedicated to address the torque ripple. However, unlike other motors driven by sinusoidal phase current waveforms, the large source current ripple of SRMs generally remains, even if the torque ripple is removed. The purpose of this paper is to propose a simple control technique of SRMs for vehicular propulsion by eliminating the source current ripple as well as the torque ripple. The proposed control is a current tracking control based on a pre-computed current profile. Because vehicular propulsion requires to instantaneously output large torque in sudden acceleration, SRMs tend to be designed to be propelled below the magnetic saturation in normal vehicle travel. Therefore, this proposed current profile is derived using a simple SRM analytical model without the magnetic saturation. In addition, the proposed current profile is determined so that the peak magnetic flux is minimized to offer high-speed current response at a high rotating velocity. Along with theoretical derivation of the proposed control, this paper also presents an experiment to verify the principle of the proposed control technique, which successfully revealed reduction of both the source current ripple and the torque ripple.

Copper Loss Analysis Based on Extremum Co-Energy Priciple for High Frequency Forward Transformers with Parallel-Connected Windings

Tomohide Shirakawa, Genki Yamasaki, Kazuhiro Umetani, Eiji Hiraki

PROCEEDINGS OF THE IECON 2016 - 42ND ANNUAL CONFERENCE OF THE IEEE INDUSTRIAL ELECTRONICS SOCIETY 1099 - 1105 2016年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

The Dowell model is widely utilized for copper loss analysis of forward transformers. However, this model is not directly applicable to transformers with parallel-connected windings. The reason is that the Dowell model requires determining the AC current of all the windings in advance of analysis, although the AC current distribution in parallel connected windings is severely affected by disposition of the windings. This issue is addressed in this paper by employing the Dowell model in combination with a novel insight that the AC current is distributed in parallel-connected windings to give an extremum of the magnetic co-energy of the transformer. Simulation and experiment were carried out; and, the results supported appropriateness of the proposed copper loss analysis method.

Simple flux-based Lagrangian formulation to model nonlinearity of concentrated-winding switched reluctance motors 査読

K. Umetani, M. Yamamoto, E. Hiraki

Electronics Letters 51 ( 24 ) 1984 - 1986 2015年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：INST ENGINEERING TECHNOLOGY-IET

© 2015 The Institution of Engineering and Technology. Practical applications of switched reluctance motors (SRMs) require control techniques that can solve large torque ripple and large current ripple in power supply. To promote development of these techniques, a simple Lagrangian formulation for flux-based nonlinear SRM models is proposed. This formulation can be analysed in combination with Lagrangian circuit models of motor drivers. The properness of the formulation is supported by an example of the analysis of the operation of a simple SRM driving system.

DOI： 10.1049/el.2015.0950

Lagrangian-based Equivalent Circuit of Basic Electric-Field Coupling Wireless Power Transfer System

Hirokatsu Umegami, Kazuhiro Umetani, Masayoshi Yamamoto, Eiji Hiraki

IEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING 10 S168 - S170 2015年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY-BLACKWELL

Electric-field coupling wireless power transfer has been commonly analyzed using the circuit model. However, the circuit behavior of this model is not necessarily apparent because their resonant modes can be far complicated than the basic LC oscillation. This issue is addressed in this paper by proposing a novel equivalent circuit for a basic wireless power transfer system. This equivalent circuit has a simpler topology than the conventional circuit model. Furthermore, the equivalent circuit allows intuitive understanding of three types of the resonant modes. Along with theoretical derivation of the proposed equivalent circuit, this paper also presents simulation results, which verified the appropriateness of the equivalent circuit. (C) 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

DOI： 10.1002/tee.22180

Novel Simple Reactive Power Control Strategy With DC Capacitor Voltage Control for Active Load Balancer in Three-Phase Four-Wire Distribution Systems

Tint Soe Win, Yoshihiro Hisada, Toshihiko Tanaka, Eiji Hiraki, Masayuki Okamoto, Seong Ryong Lee

IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS 51 ( 5 ) 4091 - 4099 2015年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

This paper proposes a novel simple reactive power control strategy for the active load balancer (ALB) in three-phase four-wire distribution systems. The proposed reactive power control strategy may be applicable for adjustment of the source-side power factor under the balanced load condition. Only dc capacitor voltage control is used in the proposed control strategy. Therefore, the calculation blocks of the active and reactive components of the load currents are not necessary. The authors, thus, offer the simplest control strategy to control reactive power under the balanced load condition on three-phase four-wire distribution feeders. The basic principle of dc-capacitor-voltage-control-based reactive power control strategy is discussed in detail and then confirmed by digital computer simulation. A prototype experimental system was constructed and tested. Experimental results demonstrate that balanced source currents with reactive power control are achieved on three-phase four-wire distribution feeders. These experimental results also demonstrate that controlling the reactive power reduces the required power rating of the ALB compared with that of the conventional unity power factor control strategy.

DOI： 10.1109/TIA.2015.2437972

Experimental Validation of Normally-On GaN HEMT and Its Gate Drive Circuit

Takaharu Ishibashi, Masayuki Okamoto, Eiji Hiraki, Toshihiko Tanaka, Tamotsu Hashizume, Daigo Kikuta, Tetsu Kachi

IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS 51 ( 3 ) 2415 - 2422 2015年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

Wide-bandgap semiconductors such as silicon carbide (SiC) and gallium nitride (GaN) are promising materials for next-generation power devices. We have fabricated a normally on GaN-based high-electron-mobility transistor (GaN HEMT) for power electronic converters. In this paper, the current collapse phenomena, which are distinctive characteristics of GaN devices, are evaluated in detail for several voltages with two switching frequencies. We also evaluate a gate drive circuit that we previously proposed for the normally on GaN HEMT with a single positive voltage source. We construct and test prototype circuits for a boost-type dc-dc converter and a single-phase full-bridge inverter with a gate drive circuit. The problems to be solved for the normally on GaN HEMT, which has a (static) voltage rating of over 600 V, are clarified on the basis of the experimental results.

DOI： 10.1109/TIA.2014.2369818

Reduced-Capacity Smart Charger for Electric Vehicles on Single-Phase Three-Wire Distribution Feeders With Reactive Power Control

Hidenori Tanaka, Toshihiko Tanaka, Takaaki Wakimoto, Eiji Hiraki, Masayuki Okamoto

IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS 51 ( 1 ) 315 - 324 2015年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

In this paper, we propose a new control algorithm to reduce the capacity of a previously proposed smart charger for electric vehicles (EVs) on single-phase three-wire distribution feeders with reactive power control. The basic principle of the proposed control algorithm is discussed in detail. It is shown that controlling the reactive power on the source side reduces the capacity of the previously proposed smart charger. A digital computer simulation is implemented to confirm the validity of the proposed control algorithm using PSIM software. A prototype experimental model is also constructed and tested. Experimental results demonstrate that balanced source currents with a power factor of 0.9, which is acceptable for Japanese home appliances, are obtained on the secondary side of the pole-mounted distribution transformer during both the battery charging and discharging operations in EVs. The capacity of dc capacitor C-DC is also reduced by 37% with the proposed reactive power control algorithm.

DOI： 10.1109/TIA.2014.2327156

Non-isolated Interleaved High Step-up Converter with Reduced Voltage Multiplier Stages and a Regenerative Turn-off Snubber

Kazuhiro Umetani, Eiji Hiraki, Masayoshi Yamamoto

2015 IEEE ENERGY CONVERSION CONGRESS AND EXPOSITION (ECCE) 125 - 132 2015年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

This paper proposes a novel non-isolated high step-up converter suitable for miniaturization by high frequency design. High step-up converters with voltage multipliers are promising for high frequency design because many of them can be free from coupled inductors or transformers, which may lower the voltage gain due to the leakage inductance or may cause significant AC conduction loss in the primary winding. However, two issues can still hinder further miniaturization. One is that many multiplier stages may be needed to achieve extremely high voltage gain. The other is that high switching frequency may be restricted by severe turn-off voltage surge caused by high speed switching. The proposed converter addresses the former by applying a recently reported technique to a non-isolated boost converter. Additionally, the converter addresses the latter by proposing a simple passive regenerative turn-off snubber implementable only by two diodes and a capacitor. Experiments verified that the proposed converter achieves high voltage gain with fewer voltage multiplier stages compared to prior non-isolated high step-up converters. Additionally, the snubber successfully reduced the turn-off surge into half approximately without apparent deterioration of the efficiency.

Lagrangian-Based Derivation of a Novel Sliding-Mode Control for Synchronous Buck Converters

Kazuhiro Umetani, Masayoshi Yamamoto, Eiji Hiraki

IEEJ JOURNAL OF INDUSTRY APPLICATIONS 4 ( 6 ) 728 - 729 2015年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：INST ELECTRICAL ENGINEERS JAPAN

Sliding-mode control for power converters is gaining significant research interest for achieving a fast transient response to a step load change in a wide operating range. However, power converters also require better dynamic load regulation against load current fluctuations slower than the step change. This paper addresses this issue by deriving a novel control method for synchronous buck converters using Lagrangian dynamics. Simulation results verified improvement in dynamic load regulation against slow sinusoidal load current fluctuations.

DOI： 10.1541/ieejjia.4.728

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