Yazar "Eguchi, Kei" seçeneğine göre listele
Listeleniyor 1 - 20 / 29
Sayfa Başına Sonuç
Sıralama seçenekleri
Yayın Comparison of different dc motor modeling techniques(Bio-Byword Scientific Publishing, 2018) Eguchi, KeiA DC motor is the most widely used actuator in the industry, especially for robotic applications such as position control of robot manipulators. When motor is used in high performance close loop motion control systems, an accurate model of motor is required for control system design[1,2]. Mathematical description of DC motor is divided into two subsystems: Electrical and mechanical subsystems. Electrical subsystem of a DC motor is simple. It consist of a resistor, an inductor and a back-EMF source. Nowadays, digital RLC meters can be found in nearly all labs. This paper study the reliability of model obtained by using a digital RLC meter. Results shows that although RLC meters can measure impedances easily and quickly, obtained values are not precious because RLC meter’s output current is in the range of mA while motor works with several Ampers.Yayın A cross-connected charge pump for energy harvesting applications(International Journal of Innovative Computing, Information and Control, 2019) Do, Wanglok; Fujisaki, Haruka; Eguchi, KeiEnergy harvesting is a process of capturing, storing and converting external energy from ambient energy. The energy harvesting systems commonly use a switchedmode power supply (SMPS) to convert energy harvested from the ambient energy. Therefore, the power converter is an essential component in terms of developing efficient energy harvesting systems. Among SMPS, inductor-less converter can be a solution. This paper suggests a new topology of charge pumps by cross-connecting two of them for efficient energy harvesting systems. With the cross-connected structure, the new topology transfers a stepped-up output to the output capacitor and load in all operation periods. This operation way can improve the power efficiency of the proposed charge pump and also decrease the internal resistance and the output capacitor’s capacitance of it. The performance of the proposed charge pump is verified by comparing with two conventional charge pumps, which is based on simulation program with the integrated circuit emphasis (SPICE) simulations and theoretical analysis. Moreover, we demonstrated the feasibility of the proposed one through the experimental circuit built on a breadboard. The proposed charge pump helps develop efficient energy harvesting systems.Yayın Design and analysis of an inductor-less cross-coupled voltage equalizer(Elsevier, 2020) Eguchi, Kei; Shibata, Akira; Do, WanglokTo equalize the imbalance in the state-of-charge (SoC) of lithium-ion cells, we propose a novel inductor-less cross-coupled voltage equalizer for series-connected batteries. Unlike existing symmetrical voltage equalizers using diode switches, the proposed voltage equalizer can balance the voltage of battery cells without a threshold voltage drop, because the diode-less design is realized by the cross-coupled structure. The performance of the proposed voltage equalizer is clarified by theoretical analysis, computer simulations, and breadboard-based experimental tests. The computer simulations and experiments reveal that the proposed voltage equalizer outperforms conventional inductor-less voltage equalizers.Yayın Design of a cross-connected charge pump for energy harvesting systems(IOP Publishing, 2017) Eguchi, Kei; Fujisaki, Haruka; Oota, IchirouFor energy harvesting systems, a novel charge pump with cross-connected structure is proposed in this paper. Owing to the cross-connected structure, the proposed charge pump can offer the output voltage to the output load at every phase. Furthermore, the proposed charge pump can reduce the number of circuit stages from the conventional charge pump. For above-mentioned reasons, the proposed charge pump can realize not only smaller internal resistance but also smaller output capacitance than the conventional charge pump. The theoretical analysis and simulation program with integrated circuit emphasis (SPICE) simulation demonstrate that the proposed charge pump outperforms the conventional charge pump in the point of power efficiency and circuit speed.Yayın Design of a dual-input cross-connected charge pump utilizing scavenged energy(Elsevier, 2020) Eguchi, Kei; Kozono, Yutaka; Ishibashi, TakaakiThis paper presents a novel dual-input cross-connected charge pump utilizing scavenged energy. The proposed converter has two input sources: a battery input and a scavenged energy input. Unlike existing charge pumps, the proposed converter alleviates the energy consumed in a battery source by utilizing the scavenged energy. Therefore, the proposed converter can extend the lifetime of a battery source. Furthermore, the cross-connected structure offers not only higher voltage gain but also faster response speed than existing charge pumps. Through theoretical analysis and simulation program with integrated circuit emphasis (SPICE) simulation, the proposed converter demonstrates high power efficiency and high output voltage, where the proposed converter is compared with series–parallel converter, traditional charge pump, and Fibonacci converter. Concretely, about 90% power efficiency can be achieved by the proposed converter when the output power is 15 ?W, and the settling time is less than 19 ?S when the output load is 500 k . Furthermore, the feasibility of the proposed converter is confirmed by breadboard experiments, where the experimental circuit is built with commercially available ICs.Yayın Design of a multi-input single-output step-up ac/dc converter with bipolar structure(Elsevier, 2020) Eguchi, Kei; Nakashima, Daigo; Shibata, AkiraFor vibration energy harvesting, we propose a multiple-input single-output (MISO) step-up ac/dc converter with bipolar structure in this paper. Unlike existing ac/dc converters for vibration energy harvesting, the proposed ac/dc converter features a bipolar MISO topology that transforms several vibration inputs to provide a step-up voltage. Furthermore, the proposed topology enables inductor-less designs. To clarify the effectiveness of the proposed converter, some computer simulations as well as breadboard-based experimental tests are performed. In the performed simulations, the voltage gain of the proposed converter with 2 modules reaches about 3.5 at 20mW and the power efficiency is about 92% at 20mW when the ac input is 3.5V at 50Hz. Furthermore, the physical feasibility of the proposed topology is proved by the breadboard-based experimental tests.Yayın Design of a non-thermal food processing system utilizing wire discharge of dual electrodes in underwater(International Journal of Innovative Computing, Information and Control, 2018) Eguchi, Kei; Jaiwanglok, Anurak; Julsereewong, Amphawan; Abe, Hiroto; Oota, IchirouTo provide nutritious and fresh processed foods, non-thermal food processing technologies have been developed in recent years. Among others, a non-thermal food processing method utilizing underwater shockwaves has cost-effectiveness. In this method, the design of a high voltage multiplier and its discharging method are key factors for processing target foods effectively. This paper proposes a non-thermal food processing system utilizing wire discharge of dual electrodes in underwater. Unlike conventional non-thermal food processing systems, the proposed system has two pairs of electrodes with thin metal wires. Owing to the electric discharge using thin metal wires, the energy to generate underwater shockwaves can be decreased. For this reason, by only one electric discharge, both sides of the target food are crushed by the proposed technique. The experiments using a laboratory prototype clarified that the proposed method can soften the whole flesh of the target food effectively. Furthermore, by assuming a four-terminal model, an equivalent model of the high voltage multiplier was analyzed theoretically. Concerning the series-connected voltage multiplier, the design conditions were derived to estimate the characteristics such as output voltage and power efficiency.Yayın Design of a Single Inductor LED Sink Driver Employing a Negative Hybrid Cockcroft-Walton/Dickson Multiplier(Ieee, 2021) Eguchi, Kei; Shibata, Akira; Ishibashi, Takaaki; Asadi, FarzinFor a lithium-ion battery input, a new LED (Light-Emitting Diode) sink driver with a single inductor is presented in this paper. Unlike existing LED sink drivers, the proposed driver consists of a negative hybrid Cockcroft-Walton/Dickson multiplier and a buck-boost converter. By connecting the negative hybrid Cockcroft-Walton/Dickson multiplier to the buck-boost converter in series, the proposed topology can provide not only a higher voltage gain but also smaller component count and simpler switching control. To confirm the effectiveness of the proposed topology, theoretical analysis, computer simulations and experiments were performed regarding the simplest proposed driver realizing 8 times gain. Furthermore, the comparative analysis clarified that the proposed driver can provide higher power efficiency and smaller component counts than conventional drivers.Yayın Design of an ınductor-less direct ac-ac converter realizing 1/4x and 4x conversion(IOP Science, 2018) Eguchi, Kei; Kuwahara, K; Oota, IchirouIn this paper, an inductor-less direct AC-AC converter realizing 1/4x and 4x conversion is designed by using switched-capacitor (SC) techniques. Unlike conventional SC AC-AC converters, the proposed AC-AC converter is synthesized with two converter blocks. By converting an AC input twice by these converter blocks, the 1/4x step-down / 4x step-up conversion is achieved by the proposed converter. The proposed converter has a simple circuit configuration, where each converter block consists of only four bidirectional switches and two capacitors. Hence, the proposed converter can realize smaller circuit components and higher input power factor than conventional converters. The effectiveness of the proposed converter was confirmed by simulation program with integrated circuit emphasis (SPICE) simulations and theoretical analysis. The SPICE simulation revealed that the proposed converter outperforms the conventional AC-AC converter using a flying capacitor.Yayın Development of a simple direct switched-capacitor ac-ac converter using cascade connection(International Journal of Innovative Computing, Information and Control, 2018) Eguchi, Kei; Abe, Hiroto; Ishibashi, Takaaki; Sasaki, HirofumiIn this paper, we propose a simple direct AC-AC converter with cascade connection by using switched-capacitor (SC) techniques. The proposed AC-AC converter is synthesized with n (= 1, 2, . . ., N) converter blocks, where each converter block realizing 1/2× step-down conversion consists of only two capacitors and four switches. Unlike conventional SC converters, power conversion of the proposed converter is achieved without a flying capacitor. Hence, the proposed converter can reduce circuit size from the conventional converters. Furthermore, high conversion ratio is realized by connecting these converter blocks in series. In other words, multiple conversion is performed by cascade topology. To evaluate the effectiveness of the proposed converter, we conducted simulation program with integrated circuit emphasis (SPICE) simulations and theoretical analysis concerning power efficiency and input power factor. The evaluation demonstrated that the proposed converter can achieve better performance than the conventional converter using a flying capacitorYayın The development of a step-down switched-capacitor inverter without flying capacitors and full-bridge circuits(Elsevier, 2020) Eguchi, Kei; Abe, Hiroto; Ishibashi, TakaakiRecently, an inductor-less inverter attracts many researchers’ attention, because the inductor-less design can provide not only small size but also small electromagnetic interference (EMI). In this paper, we propose a novel step-down switched-capacitor (SC) inverter without flying capacitors. Unlike traditional single-phase inverters, the proposed single-phase inverter has the advantages, namely, inductor-less design, downsizing by omitting flying capacitors, no full-bridge circuit, and symmetrical topology. To achieve these features, the proposed SC inverter changes the connection order of series-connected capacitors alternately. By offering a simple circuit configuration, the proposed inverter can achieve not only small EMI but also small size and high power efficiency. Furthermore, by using pulse width modulation (PWM), the proposed inverter generates a sinusoidal output without flying capacitors and full-bridge circuits. The effectiveness of the proposed inverter is justified by comparing the proposed inverter with an existing single-phase SC inverter. The simulation program with integrated circuit emphasis (SPICE) simulations demonstrate that the proposed inverter outperforms the existing SC inverter in the points of power efficiency and component counts. Concretely, about 94% power efficiency can be achieved when the output power is 2kW. Furthermore, the proposed inverter can reduce two flying capacitors from the existing SC inverter.Yayın The development of an led lighting circuit using high gain buck-boost converters(IJEETC, 2019) Kuwahara, Kyoka; Ishibashi, Takaaki; Eguchi, Keihis paper presents an LED driver using high gain buck-boost converters. By combining a traditional buck-boost converter and a Switched-Capacitor (SC) DC-DC converter with flying capacitors, the proposed driver can achieve the following features: 1) High voltage gain realized by cascade connection, 2) controllability of conversion ratio owing to the hybrid topology, and 3) small volume with only one inductor. The characteristics of the proposed driver, such as output voltage and power efficiency, were investigated by Simulation Program with Integrated Circuit Emphasis (SPICE) simulations. Furthermore, the feasibility of the proposed driver was confirmed by experiments. The simulation and experiment show the effectiveness of the proposed driver.Yayın Electronic measurements: A practical approach(Morgan & Claypool, 2021) Eguchi, KeiMeasurement is the process of obtaining the magnitude of a quantity relative to an agreed standard. Electronic measurement, which is the subject of this book, is the measurement of electronic quantities like voltage, current, resistance, inductance, and capacitance, to name a few. This book provides practical information concerning the techniques in electronic measurements and knowledge on how to use the electronic measuring instruments appropriately. The book is composed of five chapters. Chapter 1 focuses on digital multimeters. You will learn how to use it for measurement of AC/DC voltages/currents, resistance, connection test, and diode forward voltage drop test. Chapter 2 focuses on power supplies. Although power supplies are not a measurement device, they have an undeniable role in many measurements. So, being able to use power supplies correctly is quite important. Chapter 3 focuses on function generators. Like the power supplies, the function generators are not a measurement device in the first look. However, they play a very important role in many electronic measurements. So, being able to use a function generator correctly is an important skill any technician or engineer needs. Chapter 4 focuses on oscilloscopes. These days, digital oscilloscopes are the most commonly used tool in both industry and university. Because of this, this chapter focuses on digital oscilloscopes not on the analog ones which are almost obsolete. Chapter 5 focuses on drawing graph of data you obtained from your measurement. Visualization of data is very important in practical works. This chapter show how you can use MATLAB® for drawing the graph of your measurements. This book could be used a laboratory supplement for students of electrical/mechanical/mechatronics engineering, for technicians in the field of electrical/electronics engineering, and for anyone who is interested to make electronic circuits.Yayın Experiment of a high voltage gain switched capacitor dc-dc converter based on a cross-connected fibonacci-type converter(Innovative Computing, Information and Control, 2019) Rubpongse, Ratanaubol; Do, Wanglok; Eguchi, KeiTo make an efficient converter for energy harvesting systems, a high voltage gain cross-connected switched-capacitor (SC) DC-DC converter is presented in this paper. By using a cross-connected structure based on Fibonacci-type converters, the proposed converter can realize high voltage gain, where the voltage gain is expressed as a power of two. On the other hand, unlike traditional converters, stepped-up voltage is created in every clock cycle. By using the cross-connected structure, the proposed converter can reduce the size of output capacitor and output ripple noise. Therefore, the proposed converter can be compact in size. Experimentation revealed that the proposed converter can realize a high voltage gain, fast response speed, small output ripple noise, even at a small size.Yayın A high voltage gain sc dc-dc converter based on cross-connected fibonacci-type converter(IEEE, 2018) Eguchi, Kei; Pongwatd, Sawai; Fujisaki, HarukaFor energy harvesting systems, this paper presents a high voltage gain switched-capacitor (SC) converter with cross-connected topology. By cross-connecting two Fibonacci-type DC-DC converters, the proposed SC DC-DC converter provides a high stepped-up voltage which is expressed as a power of two. Unlike conventional converters, the stepped-up voltage is generated in all clock phase. Furthermore, the cross-connected structure provides the reduction of internal resistance and output capacitance. Therefore, small size and efficient energy conversion can be achieved by the proposed converter. The characteristics of the proposed converter were investigated by not only SPICE simulations but also theoretical analysis, where the proposed converter demonstrated high performance such as high voltage gain, small size, high power efficiency, and fast response speed.Yayın A hybrid LED sink driver using a nesting-type switched-inductor/switched-capacitor buck-boost converter(Elsevier, 2020) Eguchi, Kei; Bevrani, Hassan; Shafiee, Qobad; Shibata, AkiraThis paper presents a novel light emitting diode (LED) sink driver with a high voltage gain for LED-based lighting applications. Unlike conventional LED sink drivers, the proposed driver has the nested switched-inductor/switched capacitor (SI/SC) topology consisting of an SI buck-boost converter block and a nesting-type SC cell. Owing to the nested SI/SC topology, the proposed driver offers not only a high voltage gain but also a flexible controllability of the LED currents and transformer-less structure. The effectiveness of the proposed driver is justified by some simulation results in SPICE software environment and laboratory experimental tests. In the performed simulations, the proposed driver in comparison of conventional drivers improved almost 6% power efficiency when the output power was 500 mW. Furthermore, in the performed experiments, the feasibility of the proposed topology is confirmed by demonstrating a high voltage gain and the output controllability.Yayın Implementation of inductor-less 13-level inverter topology with reduced number of required component(Elsevier, 2020) Eguchi, Kei; Bevrani, Hassan; Shafiee, Qobad; Do, WanglokThis paper presents an inductor-less multilevel inverter (MLI) with a 13-level ac output. The proposed MLI consists of only 11 switches, 2 capacitors, and 2 input sources. Owing to the inductor-less symmetrical topology, the proposed MLI can reduce the component count in comparison of conventional MLIs. This leads to reduction of power loss and hardware cost. To clarify the effectiveness of the proposed MLI, the characteristic evaluation is given in detail. Some computer-based simulations in SPICE simulator environment as well as breadboard-based experimental tests are conducted concerning the proposed 13-level inverter. In the performed simulations, the power efficiency of the proposed MLI reaches about 85% and 88% at 1 kW in the case of a sinusoidal output and a triangular output, respectively. The proposed MLI improves power efficiency more than 2.5% comparing with the conventional K-type MLI when the output power is 1 kW. Furthermore, the experimental result proves the physical feasibility of the proposed topology by demonstrating the 13-level ac output. ?Yayın An LED driver connecting a nested-type SC converter and an SI buck-boost converter in parallel(IEEE, 2021) Eguchi, Kei; Shibata, Akira; Do, WanglokFor light emitting diode (LED) lighting applications, a novel hybrid LED driver with high voltage gains is proposed in this paper. Unlike existing LED sink drivers with series-connected structure, the proposed driver has the switched-inductor and switched capacitor (SISC) topology combining with an SI buck-boost converter and a nested-type SC converter in parallel. In the proposed topology, the LED cathode and anode are connected to the SI buck-boost converter and the nested-type SC converter, respectively. The characteristics of the proposed topology are analyzed theoretically. Furthermore, the validity of the proposed topology is confirmed by simulation program with integrated circuit emphasis (SPICE) simulations and breadboard experiments. The SPICE simulations and experiments reveal that the proposed driver can achieve high voltage gains and flexible controllability of outputs.Yayın A multi-input cross-connected charge pump for mobile applications(IEEE, 2018) Eguchi, Kei; Ishibashi, Takaaki; Oota, IchirouTo develop efficient mobile application systems, a multi-input cross-connected charge pump is proposed in this paper. By combing ambient energy and battery energy, the proposed charge pump achieves a long working-life of the battery. Furthermore, unlike conventional charge pumps, the converter blocks are cross-connected in the proposed charge pump. Therefore, the proposed charge pump can realize smaller ripple noise than the traditional charge pump, because the output voltage is provided to an output load at every clock cycle. To clarify the characteristics of the proposed charge pump, we conducted theoretical analysis and simulation program with integrated circuit emphasis (SPICE) simulations. The theoretical analysis revealed the characteristics such as power efficiency and output voltage theoretically. Furthermore, SPICE simulation showed that the proposed charge pump can achieve efficient power efficiency and circuit speed.Yayın A new analysis way of three-phase switched capacitor converter(World Scientific, 2019) Do, Wanglok; Eguchi, KeiThe paper presents the theoretical analysis way of the switched capacitor converter (SCC). The main goal of this research is to suggest the analysis way of three-phase SCC. A common SCC operates by two phases; charging phase and discharging phase. Therefore, state-space averaging model or slow and fast switching limit (S-FSL) model has been suitable. Although the four-terminal equivalent model can cover all situation including three-phases cases, this model does not include the parameter of frequency and capacitance. Therefore, the four-terminal model has a weakness. In this situation, we selected the Fibonacci sequence SCC operated by three-phase as the target circuit, which topology has been proved to have higher efficiency, small size in the previous research. In the paper, we suggest the new analysis way of the three-phase SCC by combination of the four-terminal equivalent model and RC circuit model from each loop equation of the equivalent circuits of the SCC. By using the suggested way, it is possible to analyze the three-phase SCC, deriving the effect of the load, operation frequency and duty ratio variation. In order to verify the feasibility and the cogency of the suggested analysis way, comparative analysis is implemented by SPICE simulations. The error in the load regulation between the suggested way and the simulation result is negligible. Through this result, we establish the foundation of the analysis of the three-phase SCC.
