Influence of Water Volume on Particle Characteristics of Iron Powder with Insulated Coating for a Compacted Magnetic Core

Funato Norikazu,Yamamoto Masayuki 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1

Seasonal changes have been recognized in particle characteristics and forming characteristics of iron powder with insulated coating for a compacted magnetic core because of its high hygroscopicity, due to its phosphate coating and resin binder additives. For this reason, particle characteristics and molding characteristics of the powder with diverse water absorbtivity have been studied. The result shows that the higher the volume of absorbed water, the worse the fluidity becomes, resulting in the reduction in both springback during the molding process and expansion reduction after the heat treatment. The requirement on dimension accuracy for the finished product can be satisfied with an additional drying process on the material powder, which contributes to maintain its water volume constant.

Hybrid Sensor-less Control of Permanent Magnet Synchronous Motor in Low-speed Region

Yamamoto, Yasuhiro,Funato, Hirohito,Ogasawara, Satoshi The Korean Institute of Power Electronics 2008 JOURNAL OF POWER ELECTRONICS Vol.8 No.4

This paper proposes a method of improving the stability in sensor-less control of permanent magnet synchronous motors. The control method for low-speed region is divided into two: One is a high frequency method, which involves a problem of reverse rotation once misdetection of the permanent magnet polarity should occur, and another one is a current drive method, which has a problem that phase and speed oscillations are caused by quick speed changes. Hence, authors propose adoption of the current drive method for the basic control system with added compensation of stabilization by means of the high frequency method. This combination secures stable control with no risk of reversal and less vibration. In addition, authors have also considered a frequency separation filter of a shorter delay time so that current control performance will not lower even when high frequencies are introduced. This filter has achieved simplified compensation using repetitive characteristic through the utilization of the periodicity of high frequency current. Simulation and experiment have been conducted to verify that the stable performance of this system is improved.

Novel Predictive Maximum Power Point Tracking Techniques for Photovoltaic Applications

Abdel-Rahim, Omar,Funato, Hirohito,Haruna, Junnosuke The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.1

This paper offers two Maximum Power Point Tracking (MPPT) systems for Photovoltaic (PV) applications. The first MPPT method is based on a fixed frequency Model Predictive Control (MPC). The second MPPT technique is based on the Predictive Hysteresis Control (PHC). An experimental demonstration shows that the proposed techniques are fast, accurate and robust in tracking the maximum power under different environmental conditions. A DC/DC converter with a high voltage gain is obligatory to track PV applications at the maximum power and to boost a low voltage to a higher voltage level. For this purpose, a high gain Switched Inductor Quadratic Boost Converter (SIQBC) for PV applications is presented in this paper. The proposed converter has a higher gain than the other transformerless topologies in the literature. It is shown that at a high gain the proposed SIQBC has moderate efficiency.

Novel Predictive Maximum Power Point Tracking Techniques for Photovoltaic Applications

Omar Abdel-Rahim,Hirohito Funato,Junnosuke Haruna 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.1

This paper offers two Maximum Power Point Tracking (MPPT) systems for Photovoltaic (PV) applications. The first MPPT method is based on a fixed frequency Model Predictive Control (MPC). The second MPPT technique is based on the Predictive Hysteresis Control (PHC). An experimental demonstration shows that the proposed techniques are fast, accurate and robust in tracking the maximum power under different environmental conditions. A DC/DC converter with a high voltage gain is obligatory to track PV applications at the maximum power and to boost a low voltage to a higher voltage level. For this purpose, a high gain Switched Inductor Quadratic Boost Converter (SIQBC) for PV applications is presented in this paper. The proposed converter has a higher gain than the other transformerless topologies in the literature. It is shown that at a high gain the proposed SIQBC has moderate efficiency.

Hybrid Sensor-less Control of Permanent Magnet Synchronous Motor in Low-speed Region

Yasuhiro Yamamoto,Hirohito Funato,Satoshi Ogasawara 전력전자학회 2008 JOURNAL OF POWER ELECTRONICS Vol.8 No.4

This paper proposes a method of improving the stability in sensor-less control of permanent magnet synchronous motors. The control method for low-speed region is divided into two: One is a high frequency method, which involves a problem of reverse rotation once misdetection of the permanent magnet polarity should occur, and another one is a current drive method, which has a problem that phase and speed oscillations are caused by quick speed changes. Hence, authors propose adoption of the current drive method for the basic control system with added compensation of stabilization by means of the high frequency method. This combination secures stable control with no risk of reversal and less vibration. In addition, authors have also considered a frequency separation filter of a shorter delay time so that current control performance will not lower even when high frequencies are introduced. This filter has achieved simplified compensation using repetitive characteristic through the utilization of the periodicity of high frequency current. Simulation and experiment have been conducted to verify that the stable performance of this system is improved.

Hybrid Sensor-less Control of Permanent Magnet Synchronous Motor in Low-speed Region

Yasuhiro Yamamoto,Hirohito Funato,Satoshi Ogasawara 전력전자학회 2007 ICPE(ISPE)논문집 Vol.- No.-

This paper proposes a method of improving the stability in sensor-less control of permanent magnet synchronous motors. The control method for low-speed region is divided into two: One is a high frequency method, which involves a problem of reverse rotation once misdetection of the permanent magnet polarity should occur, and another one is a current drive method, which has a problem that phase and speed oscillations are caused by quick speed changes. Hence, authors propose adoption of the current drive method for the basic control system with added compensation of stabilization by means of the high frequency method. This combination secures stable control with no risk of reversal and less vibration. In addition, authors have also considered a frequency separation filter of a shorter delay time so that current control performance will not lower even when high frequencies are introduced. This filter has achieved simplified compensation using repetitive characteristic through the utilization of the periodicity of high frequency current. Simulation and experiment have been conducted to verify that the stable performance of this system is improved.

Loss Analysis and Power Improvement of Non-resonant Type Capacitive Power Transfer System With Three-level Operation

T. Kitabayashi,H. Funato,J. Haruna,Y. Tsuruta,K. Yamaichi 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

The authors have proposed a new capacitive power transfer (CPT) system using one-pulse switching active capacitor (OPSAC). The proposed system improves transfer power without LC resonance so that it is robust against parameter change. The one of advantages of OPSAC is easy realization of cascade connection in order to enhance transfer power. In the past, CPT system with five-stage OPSAC was successfully realized, but the actual transfer power was smaller than theoretical power. In this paper, loss factor is analyzed using precise calculation model. In addition, from the results of loss analysis, it was clarified that the one of the main loss factor is diodes of rectifier so that the system using synchronous rectifier is also proposed for power improvement.

Improvement of Capacitively Isolated Outlet and Plug for Practical Use

Junnosuke Haruna,Hirohito Funato,Takuya Hatsumi,Toshiki Uemura,Yusuke Kose 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

Isolated outlet and plug is suitable for DC power distribution to avoid arcing at detach. Authors have proposed isolated outlet and plug using comb type capacitor in order to realize large coupling capacitance for larger transfer power. Over 40W power transfer was realized using prototype capacitive couplings and half-bridge inverter with LC series resonance. The size of prototype capacitive coupling is same to conventional double outlet socket in Japan (120mm x 75mm x 45mm). Although the size is not so large, it is difficult to insert and remove due to large number of teeth. In this paper, smaller and simpler comb type capacitor is proposed using higher frequency in order to realize practical isolated outlet and plug.

Novel Fixed Frequency Predictive Hysteresis Maximum Power Point Tracking Control for Photovoltaic Applications

Omar Abdel-Rahim,Hirohito Funato,Junnosuke Haruna 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

a novel Maximum Power Point Tracking (MPPT) control for Photovoltaic applications is proposed in this paper. The proposed control algorithm is two-stage control system. The first-stage is a Modified Incremental Inductance (MIC) algorithm and the second stage is based on Fixed Frequency Predictive Hysteresis Control (FFPHC). The purpose of the MIC stage is to generate the required reference current that achieves the maximum power. And the function of the FFPHC is to force the system to track that reference. The proposed control algorithm has some inherent features such as ability to achieve maximum power even in case of rapid environmental changes, ability to achieve maximum power in case of partial shading. Operation of predictive hysteresis control at fixed frequency gives the advantages of better power stage parameters design and enables controlling the switching losses.

An Efficient and High-gain Inverter Based on The 3S Inverter Employs Model Predictive Control for PV Applications

Omar Abdel-Rahim,Hirohito Funato,Haruna Junnosuke 대한전기학회 2017 Journal of Electrical Engineering & Technology Vol.12 No.4

We present a two-stage inverter with high step-up conversion ratio engaging modified finite-set Model Predictive Control (MPC) for utility-integrated photovoltaic (PV) applications. The anticipated arrangement is fit for low power PV uses, the calculated efficiency at 150 W input power and 19 times boosting ratio was around 94%. The suggested high-gain dc-dc converter based on Cockcroft-Walton multiplier constitutes the first-stage of the offered structure, due to its high step-up ability. It can boost the input voltage up to 20 times. The 3S current-source inverter constitutes the second-stage. The 3S current-source inverter hires three semiconductor switches, in which one is functioning at high-frequency and the others are operating at fundamental-frequency. The highswitching pulses are varied in the procedure of unidirectional sine-wave to engender a current coordinated with the utility-voltage. The unidirectional current is shaped into alternating current by the synchronized push-pull configuration. The MPC process are intended to control the scheme and achieve the subsequent tasks, take out the Maximum Power (MP) from the PV, step-up the PV voltage, and introduces low current with low Total Harmonic Distortion (THD) and with unity power factorwith the grid voltage.