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This paper comprehensively evaluates the PV power smoothing control method using the spline function. As a result of the verification, it is shown that the ESS capacity can be reduced while maintaining the smoothing effect by PV power smoothing control with energy control and limiting fluctuation rate control. Based on the charging/discharging power of the ESS and the operating conditions of the ESS, the section time that achieves both improvement of the smoothing effect and reduction of the ESS capacity is determined to be 1500 s. Then, the rated capacity of the ESS for a rated power of 1.75MW PV system is 1128 kWh. This is 49.6% of the rated capacity of the ESS, which is required in the PV power smoothing control method with fluctuation rate control. As a result of comparing the proposed method and the moving average method, the proposed method improved the smoothing effect by 49.8% compared to the moving average method. [ABSTRACT FROM AUTHOR]

Accurately calculating the transmission‐line constants of underground cables is important for various types of power system simulations such as electromagnetic transient, power flow, and transient stability simulations. The transmission line constants of cables installed in a tunnel must be calculated taking the skin and proximity effects into account, since the cables are spaced closely to each other and also to a wall face of the tunnel. However, the conventional method, which is capable of considering the skin and proximity effects, has been restricted to circular cross‐section conductors such as cables and a circular tunnel. Therefore, the method cannot handle a tunnel with a rectangular cross section. In this paper, a method for calculating the transmission‐line constants of a conductor system in which both circular and rectangular cross‐section conductors present in the same space is proposed. Then, the walls of a rectangular tunnel are represented by eight rectangular conductors, and cables represented by circular conductors are placed inside the eight rectangular conductors. In this paper, the proposed method is verified by experiments using a conductor system in which three circular conductors are arranged in a rectangular conductor. Calculated results obtained by the proposed method agree well with the measured results. [ABSTRACT FROM AUTHOR]

This paper proposes a new gradient driver with a gradational voltage inverter for low power loss and downsized filter circuits. Gradient drivers produce direct current with low ripple amplitudes to achieve high image quality and high slew rates to obtain images rapidly. The proposed gradient driver is characterized by low ripple amplitude of the output current from the inverter composed of SiC‐MOSFETs and high output voltage from another inverter composed of IGBTs. This paper discusses both the principle of operation and control method of the new gradient driver. Experimental verification is performed on a full‐scale system. The results show the advantages of the proposed gradient driver based on loss analysis by calculations. [ABSTRACT FROM AUTHOR]

This paper proposes an efficient method for photovoltaic (PV) system output forecasting by deep Boltzmann machines (DBM) with scatter search‐predator‐prey brain storm optimization (SS‐PPBSO). DBM plays a key role to extract features of input variables while SS‐PPBSO is a new evolutionary computation that combines PPBSO with scatter search. In recent years, as renewable energy, PV systems are positively introduced into power network in Japan so that power system operation becomes complicated due to the uncertainty. To overcome this challenge, it is required to forecast PV outputs that are influenced by weather conditions significantly. This paper proposes a new efficient PV output forecasting method with DBM that makes use of SS‐PPBSO in learning. The effectiveness of the proposed method is demonstrated for real data of a PV system. [ABSTRACT FROM AUTHOR]

Electric vehicle (EV) will prevail in the near future and many EVs are expected to be parked all day or almost all day according to a survey in Japan. They can contribute as vehicle‐to‐grid (V2G) to primary frequency regulation in power systems. However, as lithium‐ion battery or EV battery is still expensive, it is economically important to evaluate V2G frequency regulation cost. This paper proposes the evaluation method of the frequency regulation cost. The proposed method is based on the EV battery cost and longevity, which is shortened by performing the frequency regulation. The battery degradation consists of calendar aging and cycle aging, and an empirical model is used in this paper. Simulation results are shown using the proposed method under the various conditions such as state of charge (SoC) of the EV battery. Those results indicate a V2G control strategy to increase the cost–benefit of primary frequency regulation. [ABSTRACT FROM AUTHOR]

Although FRT capability is claimed in Japanese grid code for RE, DVS capability is not. In some European countries, not only FRT but also DVS is claimed. Whether this choice of our grid code is pragmatically adequate or not? To answer the question, it is necessary to evaluate FRT and DVS capabilities. But the past studies only evaluated qualitative merit of FRT and DVS, or evaluated quantitative merit on fictional system models. Since the authors intend to evaluate FRT and DVS capabilities in existing power system of Japan, some method for the evaluation must be invented. For the evaluation, values of FRT and DVS capabilities are evaluated by reduction amount of stabilizing equipment (i.e. SVC in the paper). The evaluation based on strict optimal SVC disposition is quite difficult, because existing power system must be adequately modeled, because number of SVCs is large and because every power flow conditions must be considered. However, semi‐optimal SVC disposition can be calculated as shown in the paper. As the result, value of FRT is quite larger than value of DVS. And then, our grid code is proved as pragmatically adequate, except some flaw in claimed FRT design that is introduced in the paper. [ABSTRACT FROM AUTHOR]

In recent years, there has been an increasing demand for position sensorless control in Permanent Magnet Synchronous Motor (PMSM) drives, and various methods have been studied. Switching noise is a problem in the low‐speed sensorless control method that uses the current slope during PWM. Furthermore, another problem is that the inductance does not appear in a sinusoidal distribution owing to magnetic saturation. In this paper, we improve the sensorless control method that estimates the position from the current slope during PWM, which is greatly affected by switching. Additionally, we build a multi‐layer neural network (NN) that directly estimates the position signals by learning a large amount of current data, and verify the driving results in the low‐speed range when the learned NN is incorporated into real‐time control. [ABSTRACT FROM AUTHOR]

Renewable energy generation systems are promising energy sources; however, they have a problem that they do not have, in general, inertia and synchronous power. A system with low inertial and synchronization forces has low stabilizing capability, and such systems are vulnerable to network fault and can cause large frequency fluctuations. This paper focuses on a large storage battery and a permanent magnet synchronous generator (PMSG) based variable‐speed wind power generator, and a new cooperative virtual inertia and reactive power control system between them which is based on Fuzzy Logic controller (FLC) and asymmetric hysteresis deadband is proposed and designed. Its effectiveness on the system stability enhancement during a grid fault is confirmed by simulation analyses on PSCAD/EMTDC. [ABSTRACT FROM AUTHOR]

In this paper, a reference stator flux linkage calculation method is proposed for realizing maximum efficiency operation in direct‐torque‐controlled interior permanent magnet synchronous motor (IPMSM) drives. The proposed method is based on the solutions of a quartic equation, a motor model in the d‐q rotating frame widely used for synchronous motor controllers, and a well‐known equation for maximum efficiency operation. Therefore, the proposed method uses neither any approximation function nor any look‐up table that depends on the parameters of the motor, which has to be created in advance. Simulation results validate that the proposed methods can achieve maximum efficiency operation in IPMSM drives. [ABSTRACT FROM AUTHOR]

This paper proposes a self‐conducting current bypass circuit for series‐connected diodes in high power semiconductor light source. This circuit enables the main circuit current flow continuously, even if several of the diodes connected in series are open because of breakdowns. Herein, the composition, operation, and circuit design method of the proposed circuit are described. Moreover, the development of a simulation model of the fuse, which is an element of the circuit, is described. Furthermore, the simulation result of the proposed circuit using the fuse model is presented, and the method of determining the circuit constant based on the simulation result is demonstrated. Finally, by connecting a prototype circuit based on this study in parallel with series‐connected diodes, we show that the main circuit current of 60 A flow continuously even when one of the diodes is open. [ABSTRACT FROM AUTHOR]

A multiphase DC‐DC converter consisting of a coupled inductor and fast switching devices enables power electronics equipment to achieve a high‐power density. However, with such devices, the fast voltage transition generates substantial common mode (CM) noise. However, there are very few studies on CM noise reduction for multiphase converters using a coupled inductor. Therefore, in this paper, a CM noise reduction method is proposed for a multiphase DC‐DC converter that hardly lowers the power density. [ABSTRACT FROM AUTHOR]

This paper proposes methodology and gate drive circuit that can immediately detect short‐circuit (SC) of multiparalleled SiC‐MOSFETs even under current imbalance condition. Proposed method detects SC current using an integration circuit that can sense di/dt. The detection level of SC current can be adjusted to a desired value regardless of the number of SiC‐MOSFETs connected in parallel. The effectiveness of the proposed approach was experimentally validated for four‐paralleled SiC‐MOSFETs under extreme current imbalance in SC condition. SC was detected within 0.5 μs and all SiC‐MOSFETs were protected without destruction at most 2.2 μs after the onset of SC, for all types of SC 1, 2, and 3. [ABSTRACT FROM AUTHOR]

In Japan the electricity market will open on April 1, 2004. Electric utility, Power Producer and Supplier (PPS), and Load Service Entity (LSE) will join the electricity market. LSEs purchase electricity based on the Market Clearing Price (:MCP) from the electricity market. LSEs supply electricity to the customers that contracted with the LSEs on a certain electricity price, and one to the customers that introduced Energy Storage System (:ES) on a time-of-use pricing. It is difficult for LSEs to estimate whether they have any incentive to promote customers to introduce ES or not. This paper evaluates the reduction of LSEs' purchasing cost from the electricity market and other LSEs' purchasing cost by introducing ES to customers. It is clarified which kind of customers has the effect of decreasing LSEs' purchasing cost and how much MCP of the whole power system the demand-side energy storage systems change. Through numerical examples, this paper evaluates the possibility of giving the cost merit to both customers with energy storage systems and LSE by using real data for a year's worth of MCP. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 158(1): 22–35, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20447 [ABSTRACT FROM AUTHOR]

A three‐legged wound transformer core is composed of two inner cores and one outer core, and the interlaminar flux occurs between inner and outer cores in three‐phase excitations. Past analyses of magnetic properties of three‐legged wound transformer cores were based on the model of independent magnetic paths in the individual core, and did not factor the influence of interlaminar flux in the calculations. This paper shows experimental results of interlaminar flux between cores and iron loss increase caused by that. Results show that the interlaminar flux between the inner and outer core increases the local iron loss in the boundary region of the inner and outer core. [ABSTRACT FROM AUTHOR]

We are planning to develop the new Advanced Distribution Automation System (ADAS) equipped with optical communication network and sectionalizer with sensor for more grid reliability and efficiency on maintenance operation. The new system is featured with the function of fault cause or damaged part estimation. The new sectionalizer captures the waveform of electrical line surge originated by fault and the system analyzes the waveform for this function. This paper mainly introduces the system configuration of ADAS and an early stage examination of fault cause estimation technology. [ABSTRACT FROM AUTHOR]

Recently, energy harvesting has attracted increasing attention. The present study focuses on vibration generators based on piezoelectric elements by proposing an internal capacitor cancel control (ICCC) rectifier to improve the output power. The proposed rectifier cancels the internal capacitor to improve the output power while retaining the maximum output power. Accordingly, this paper experimentally demonstrates the improvement in output power by using the ICCC rectifier compared to conventional circuits and the previous proposed circuit. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the losses caused by circulating currents generated in armature windings of permanent magnet synchronous machines by using electromagnetic field analysis. In the analysis, each parallel connected wire in the windings is modeled by finite elements in order to consider the difference in the electromotive forces and the generation of the circulating currents. The calculated losses are compared with experimental results. It is clarified that the armature copper loss in permanent magnet machines with parallel connected wires considerably increases by the circulating currents. [ABSTRACT FROM AUTHOR]

A novel design of a single‐phase synchronous inverter (SSI) having noninterference core dynamic performance is proposed, referred to as noninterference core SSI (NIC‐SSI) in this paper. The proposed inverter consists of "core" and "shell." This novel design is advantageous for a flexible setting of the core controller to enhance power system stability, which is supported by the shell function for keeping robust synchronizing operation of inverters including microgrid operation. The novel points in this paper are summarized as: (a) the proposed controller enables SSIs to implement directly a desired dynamic characteristic such as a synchronous machine; (b) it can connect any single‐phase systems as well as three‐phase systems; (c) an islanded single‐phase microgrid without rotating machines can be stabilized by multiple SSIs. The proposed controller makes it possible to enhance system stability against increasing uncontrollable renewable energy sources (RESs) and static power conversion devices. The developed SSI realizes flexible use in the demand side operations under normal/faulted grid conditions. Hardware‐in‐the‐loop (HIL) testbed including the proposed digital controller and the real‐time simulator validates the effectiveness of the proposed controller in the experimental conditions. [ABSTRACT FROM AUTHOR]

Recent growth of renewable energy generations with natural variability, such as photovoltaic generation and wind turbine generation, would make the demand and supply control in a whole power system more difficult, and therefore, alternatives for demand and supply regulation resources would be required. The authors focus on cogeneration system (CGS) as one of regulation resources. In order to procure adequate volume of regulation capability, an aggregator coordinates a number of CGSs efficiently and flexibly considering the wide variety of electricity/thermal demands of CGS owners. This paper proposes a novel optimal operation strategy of CGS coordinated by the aggregator considering the energy balance and operation cost of individual CGS owner. This paper also demonstrates the availability of CGSs for regulation capability by numerical case studies in which the actual consumption profile is employed. [ABSTRACT FROM AUTHOR]

This paper proposes an optimal coil layout of wireless power transfer (WPT) systems for underwater vehicles (UVs). The power supply station adopts a multicoil arrangement with a double layer, and the UV also uses two receiving coils. The proposed WPT system for UVs has a reasonable advantage, where it does not request to adjust the relative position of coils. This paper experimentally discusses an optimal coil layout based on measurement results of a coupling coefficient. As a result, the proposed coil arrangement with the geometry rule realizes a certain power transfer under any positions and directions of UVs. [ABSTRACT FROM AUTHOR]

This paper provides a novel equilibrium model for analyzing behaviors of the electric retailers under competitive environment. In the deregulated electricity retail market, the retailers purchase the electricity power and sell it to consumers at the competitive prices. According to their risk attitudes, the retailers optimize the selling prices and the purchase allocation between a day‐ahead market and forward contracts. Without the regulation, an equilibrium by those selfish decision‐making processes of multiple retailers would cause an adverse impact on the electricity market and also the power system. From stable and economical viewpoints, it is important to analyze the unfavorable equilibrium. The selfish behaviors of retailers are modeled as an equilibrium problem with equilibrium constraints in this paper and formulated as a mixed integer linear programming problem to obtain a generalized Nash equilibrium by commercial solvers efficiently. Through computational examples, the proposed model and formulation are validated. [ABSTRACT FROM AUTHOR]

In this paper, a touch fault calculation method is proposed based on the symmetric coordinate method. The touch fault in this paper means that a line‐to‐line short circuit fault occurred on parallel transmission lines stringing on a same tower. It is known that the touch fault occurs very rarely such as the galloping phenomena, and it causes an abnormal voltage rise especially on a low‐voltage transmission line. However, a quantitative analysis method of the abnormal voltage has not been proposed. Therefore, a general analysis method of the voltage profile solution for the touch fault is proposed based on the symmetrical coordinate method. The proposed method is able to calculate the precise voltage and current profile solution efficiently by introducing the similar formation for the touch fault solution same as the general fault solution. Demonstrative result to the application in the touch fault calculation is presented in order to verify the practicability of the proposed method. [ABSTRACT FROM AUTHOR]

This paper outlines the development of a 500 kV dc oil-filled submarine cable capable of transmitting 2800 MW with a ±500 kV 2800 A bipole system. Although polypropylene laminated paper (PPLP) has been employed as ac cable insulation material, this is the world's largest first application to dc cables. The conductor size is 3000 mm2, which would be the largest size for submarine cables. Various fundamental and prototype tests have proved that the cable has excellent characteristics electrically as well as mechanically. The cable and accessories are currently undergoing a long-term accelerated aging test as a final confirmation of their reliability and stability. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 120(3): 29–41, 1997 [ABSTRACT FROM AUTHOR]

In this paper, we measured the electrical potential distribution of surface dielectric barrier discharges (SDBD) caused by alternating voltage in synthetic air and nitrogen using the Pockels effect. It was shown that different potential distributions of filament thickness and length are generated in synthetic air and nitrogen. A filament analysis based on mathematical morphology was performed to quantify the geometric characteristics of the filaments produced in each gas atmosphere. The results show that the discharge filament thickness and the entropy in the filament direction depend on the oxygen ratio and the magnitude of the applied voltage. [ABSTRACT FROM AUTHOR]

Permanent magnet synchronous motors (PMSM) are very popular in the industrial market. Recently, robots are installed to compensate for the shortage of labor. Due to the increase in motors, the number of power lines and position sensor cable wiring are increased; this increase in complicated wiring is a problem. As a method to solve these problems, power superimposition technology in the power line of a PMSM is expected to reduce the distribution cables. In this paper, the power superposition technology method, and circuit equations of mounting transformers in power lines are presented and are then verified by experiment, simulation, and linear analysis. The circuit equation is proposed as a three‐phase circuit equation, which is transformed into a dq‐circuit equation by a transformation matrix. The characteristics of the electric angular frequency versus the dq‐axis voltage demonstrated satisfactory results, with errors within 1% in linear analysis and simulation. The linear analysis and experiment are shown to be similar, although there are some errors. The validity of the circuit equations could be demonstrated by the verification results. [ABSTRACT FROM AUTHOR]

This paper describes the observed position dependent emission spectrum and vacuum ultraviolet (VUV) to clarify the optical structure of argon atmospheric pressure plasma jets (APJs). Visible emission spectra of argon, nitrogen, and OH molecules were measured as a function of position from the nozzle of plasma jet generator to gas flow direction. From the results, we realized that a certain electric field is required for producing high energy excited atoms of argon in the jet from the high voltage electrode in the device to the ground positioned at downstream side. Moreover, VUV was detected along the plasma jet through the downstream direction. Thus, we could picture that the light pattern of plasma jet of which intensity weaken depend to the distance from the nozzle is sustained by the above two factors with the present steady state experiments. [ABSTRACT FROM AUTHOR]

Since a motor drive system contains an inverter (high‐voltage circuit) and gate drive circuits (low‐voltage circit) with a switching regulator, electromagnetic noise is generated in each of these two circuits, and noise interference between these circuits can occur. This paper discusses noise interference between the high‐ and low‐voltage circuits of an electric compressor system with an integrated mechanical and electrical structure. Analysis using LTspice shows that the experimental and analytical results are in good agreement when a very small stray capacitance occurs between the high‐ and low‐voltage circuits. An experiment using an actual compressor showed that conducted noise above 20 MHz can be reduced by up to 10 dB by reducing the effect of stray capacitance between these circuits. [ABSTRACT FROM AUTHOR]

A model expressing beams, pillars, and electrical wiring in a building for lightning surge simulation by circuit analysis method is proposed in this paper. The proposed model expresses the self‐surge impedance of the electrical wiring as a function of the distance between conductors and the radius of the electrical wiring. The mutual impedance is expressed by the distance between the surfaces of a structure and a nearby wire instead of the distance between the conductor centers. In the case of two conductors having far different radii in proximity, the distribution of electromagnetic fields around the two conductors is similar in horizontal and vertical arrangements. Thus, the electrical wiring nearby pillars can be treated as a horizontal conductor. The circuit analysis results show that the voltage difference generated between the structure and the electrical wiring is calculated more precisely by the proposed model than by the conventional model. [ABSTRACT FROM AUTHOR]

High step‐up boost converters with large input current capacity are necessary for low‐voltage renewable energy sources, such as photovoltaic panels and fuel cells. Interleaved converters are a suitable topology for low‐voltage, large input current applications. Conventional interleaved converters, however, face a variety of challenges, such as the necessity of additional current control loops for active current balancing, increased voltage stress of semiconductors, and poor extendibility. In this paper, highly extendable interleaved high step‐up boost converters with a passive current balancing and reduced semiconductor voltage stresses are proposed. Current capacities and step‐up conversion ratios of the proposed converters can be arbitrarily enhanced by extending the number of phases and voltage multiplier (VM) stages, respectively. The experimental results of 500‐W prototypes demonstrated passive current balancing, reduced semiconductor voltage stresses, and enhanced step‐up conversion ratios. [ABSTRACT FROM AUTHOR]

In this paper, we have fabricated surface acoustic wave (SAW) devices with six sets of interdigital transducers (IDTs) on half‐inch wafers of quartz with deposited thin films of aluminum nitride (AlN). Firstly, AlN thin films have been deposited by reactive sputtering in Ar‐N2 gas mixture at 400°C with the high‐power impulse magnetron sputtering (HiPIMS) system which was developed for microfabrication process in the localized clean environment with half‐inch wafer (Minimal Fab). After that, IDTs of Al thin films have been prepared on the AlN thin films. The X‐ray diffraction (XRD) pattern of the AlN thin films shows that the AlN films have c‐axis (002) orientation. Furthermore, the frequency responses have been measured with four paired IDTs of the SAW devices, which were selected from six sets of IDTs as an input electrode and an output electrode. These results show device properties responding to the design of the IDTs and also suggest the potential of the fabricated SAW devices as the four‐paralleled frequency filter and/or sensing system. [ABSTRACT FROM AUTHOR]

In critical mode power factor correction (PFC), the switching frequency is varied to achieve a sinusoidal input current waveform. Under certain conditions, a higher frequency increases the loss and noise. Meanwhile, the limitation of the switching frequency leads to an increase in input current distortion. This paper proposes a method to prevent an increase in distortion by compensating the pulse width at a limited frequency. Using this control method, critical mode PFC with a limited maximum switching frequency was evaluated. As a result, the total harmonic distortion of the input current was lower than that before the frequency limitation. Furthermore, the improvement in efficiency and the reduction in conducted EMI were confirmed. [ABSTRACT FROM AUTHOR]

This paper proposes a new method for input current control of power factor correction (PFC) with continuous conduction mode (CCM), which does not require input voltage detection. As a control method that does not use input voltage detection, pulse width modulation (PWM) with the inductor current as the modulated signal is already in practical use however, this approach has limitations for the range of inductance values used. In CCM‐PFC, the input rectified voltage and low‐frequency component of the voltage of the switching circuit are approximately equal in the stable state as well as proportional to the PWM signal. This study uses the previous modulated signal as the estimated voltage value to generate an instantaneous current command for feedback control. In addition, a method to suppress the influence of the DC voltage ripple by changing the voltage control gain according to the value of the DC voltage was employed. From the evaluation, it was confirmed that the harmonics of the input current were suppressed within the specified range of values. [ABSTRACT FROM AUTHOR]

In this paper, a calculation method is proposed for the radial suspension force of a bearingless motor with a surface‐mounted permanent magnet (SPM) rotor, a consequent‐pole permanent magnet (CPM) rotor, and a homopolar permanent rotor (HPM). The radial suspension forces are calculated mathematically and analytically using the airgap flux density. It was confirmed that the proposed radial force equations are practical to calculate the suspension force based on the airgap flux density. The CPM bearingless motor and bearingless AC HPM have salient pole rotors that interact with the 2‐pole Magnetomotive force (MMF) to generate 6‐ and 10‐pole components. As a result, the radial suspension force of the CPM bearingless motor is generated by 8‐ and 6‐pole, and 8‐ and 10‐pole magnetic flux, whereas the bearingless AC HPM produces the radial suspension force by DC and 2‐pole components. The shaft torque, the suspension force, and efficiency were also compared for SPM, CPM bearingless motors, and bearingless AC HPM. Consequently, the torque value of the CPM bearingless motor is quite close to SPM bearingless motor. Moreover, the suspension force of the CPM bearingless motor is quite close to bearingless AC HPM. [ABSTRACT FROM AUTHOR]

In order to improve the mileage per charge of battery electric vehicles (BEV), dynamic wireless power transfer systems are being developed. There are some problems such as is the wide gap between coils when mounted under the floor of a vehicle, and the effect of foreign objects between coils on power transmission. In‐wheel coils, in which the coils are placed inside the wheel, have been proposed as a solution to these problems. However, they a plastic wheel such as CFRP and cannot reduce the gap between coils. In this paper, we propose a coil configuration in which the coils are placed inside the tire and the wheel. This configuration has the advantage of using a conventional aluminum to reduce the gap between coils. The effectiveness of this method is demonstrated via simulations and experiments. [ABSTRACT FROM AUTHOR]

This paper proposes the application of an adjustable speed diesel engine‐driven power plant employing a doubly‐fed induction generator to an isolated small‐scale power system including renewable power sources. This type of power plant can contribute to fast and flexible power balancing regulations under vacillating power supplies such as wind, solar, and other renewable power sources. Installation of a battery system is also considered, which can assist coordinately with the power plant to augment renewable power sources in the isolated power system. [ABSTRACT FROM AUTHOR]

SUMMARY Electro-magnetic interface (EMI) noise radiated from the dc cable of photovoltaic power conditioner systems (PCSs) is a serious problem for radio transmission equipment. In order to prevent the interference, the International Special Committee on Radio Interface (CISPR) is discussing to determine a noise regulation value for this issue. To reduce the radiated noise, this paper studies the attenuation characteristics of EMI filters that are connected to both the dc and the ac sides of the PCS. In this paper, it is pointed out that the EMI filters do not show their own attenuation characteristics if those are connected to the PCS. In particular, when EMI filters are connected to both the dc and the ac sides of the PCS, a specific series resonant frequency is observed and deteriorates the attenuation characteristics of both EMI filters. In order to prevent this problem, a design method for EMI filters which can reduce the common-mode EMI noise effectively, is proposed in this paper. Further, the effectiveness of the proposed method is confirmed through experiments. [ABSTRACT FROM AUTHOR]

SUMMARY This paper proposes a method to predict the charging current, the output power, and the power transfer efficiency of a low-power, noncontact charger with reasonable accuracy. The low-power, noncontact charger model considered in this paper consists of a sinusoidal voltage source, a sending and receiving coil, a full wave rectifier circuit, and an AA nickel metal-hydride battery. The capacitor that is connected in series in the sending coils of the low-power noncontact charger model to improve the power factor was also examined. The self-inductance, the mutual inductance, and the resistances of the coils were calculated using axisymmetric finite element analysis, and were substituted into the circuit equations. The circuit equations were solved by using the Runge-Kutta method. The calculated charging current, output power, and power transfer efficiency were in good agreement with the experimental results. [ABSTRACT FROM AUTHOR]

This paper proposes a method for extracting the lip shape from the region around the lips. It is carried out without limited conditions such as lipstick or lighting. The proposed method uses color information for the lip shape extraction. They are psychometric quantities of a metric hue angle (hab), rectangular coordinates (a*), which are defined in the CIE 1976 L*a*b* color space. The method employs fuzzy reasoning in order to consider obscurity in image data such as a shadow on the face. The conditional membership function for characteristics in each class was defined by the triangular membership function and was used for the fuzzy reasoning. In order to reduce the effect of the data acquisition conditions, an extraction method is here presented for the lip shape from the region around the lip through fuzzy reasoning. We studied the setup of the conditional membership function. The proposed method uses the a* color histogram and hab color histogram for the region around the lips when setting up the conditional membership function. This paper clarifies that the lip was able to be extracted without any special conditions such as lipstick or lighting. The experimental results indicate the effectiveness of the proposed method; about 98.7% of facial image data was extracted correctly. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(1): 20– 28, 2006; Published online in Wiley InterScience (http://www.interscience.wiley.com). DOI 10.1002/eej.20401 [ABSTRACT FROM AUTHOR]

The results of strict defect control include both the enhancement of manufacturing yield and increased delivery delay due to a drop in the machine operation rate. Therefore, defect inspection methods must be optimized for this trade-off, especially for ASIC manufacturing. In the first paper, we proposed a new manufacturing model which treats not only inspection and the yield model, but also the workflow model. In this paper, we formulate the inspection parameter dependence on the manufacturing yield and the machine cleaning cycle, which may affect delivery time. By using the resulting formulas, factory engineers can obtain practical information for inspection parameter optimization. [ABSTRACT FROM AUTHOR]

This paper proposes a new speed servo system for a PM motor without a current sensor, which is constructed by the current simulator of a PM motor. The proposed speed servo system is simple and economical. The sensor of the proposed system is only a position sensor used as an encoder. Hence, the proposed speed servo system has little influence on the switching noise of a PWM inverter. Moreover, the resolution of the proposed current simulator can be higher than that of the conventional actual feedback system. In this paper, the experimental results point out that the proposed current sensorless speed servo system has the desired current and speed response. The current waveform of the proposed system is smooth and clean. Moreover, this paper proposes a new identification algorithm for motor resistance Ra and main flux Φfa by using only a position sensor. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(3): 64–73, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10084 [ABSTRACT FROM AUTHOR]

Abstract: A novel circuit topology for a single‐phase inverter with a power decoupling capability operated in discontinuous current mode (DCM) is proposed in this paper. An inverter connected to a single‐phase grid requires a power decoupling capability to compensate for a power ripple with twice the grid frequency. Bulky capacitors are used as DC‐link capacitors in conventional systems. In contrast, the proposed circuit topology can use ceramic capacitors instead of electrolytic capacitors by reducing the required capacitance based on the active buffer concept. Moreover, this active buffer requires no additional inductor because it uses DCM for the power decoupling capability. In this paper, a control method for the active buffer circuit operated in DCM is introduced. An experimental verification of a 1‐kW prototype shows that the proposed circuit reduces the input current ripple at twice the grid frequency by 96.8%, with a maximum efficiency of 95.2%. In addition, the Pareto optimization of power density and efficiency is used to clarify the maximum power density points. It is found that the maximum power density of the proposed circuit is 1.6 times higher than that of a conventional boost‐type active buffer. [ABSTRACT FROM AUTHOR]

Abstract: This paper proposes a design method of strong stability self‐tuning controller based on on‐demand type feedback control. For safety in industrial applications, although it is important to consider on‐demand type feedback control system, the previous papers about on‐demand type feedback control did not consider the influence of noise and fixed the design parameter to constant value. Therefore, this paper extends the design parameter of on‐demand type feedback control as stable rational function through the design method of strong stability system using coprime factorization. Moreover the self‐tuning controller of the proposed method is given and the control result with noise is shown by numerical example. [ABSTRACT FROM AUTHOR]

Abstract: Recently, wind power generation are installed as a countermeasure for the environmental issue in Japan. However, wind power generation output is fluctuated due to wind condition. Moreover, it is some negative impact for system operation such as the economic load dispatching control and the load frequency control. In Japan, NEDO has started the project as a countermeasure for massive penetration of wind power generation in 2014, called “R&D Project on Grid Integration of Variable Renewable Energy.” In this paper, we proposed the output fluctuation suppression control method of wind power generation using the battery and forecast data of wind generation output. Specifically, the target value of wind power generation output is calculated to decrease the deviation output from fluctuation suppression code for ramp event using deterministic optimization method. The effectiveness of proposed method is evaluated through the computational simulation using forecast data and actual wind power generation output in Tohoku area. [ABSTRACT FROM AUTHOR]

Abstract: To decrease lightning damages to wind turbines and maintain public safety around the wind turbines, it is very important to improve wind‐turbine performance related to lightning protection and minimize damage to the wind turbine. In this paper, we summarize the latest trends in technologies for sound operation of wind turbines against lightning. [ABSTRACT FROM AUTHOR]

Abstract: This paper proposes a new power decoupling method for a high‐frequency cycloconverter which converts the single‐phase line‐frequency ac input to the high‐frequency ac output directly. The cycloconverter consists of two half‐bridge inverters, two input filter capacitors, and a series‐resonant circuit. The proposed power decoupling method stores the input power ripple at double the line frequency in the filter capacitors. Therefore, the proposed method achieves a unity power factor in ac input and a constant current amplitude in the high‐frequency output without any additional switching device or energy storage element. This paper theoretically discusses the principle and operating performance of the proposed power decoupling method, and the viability is confirmed by using an experimental isolated ac‐to‐dc converter based on the high‐frequency cycloconverter. As a result, the proposed power decoupling method effectively improved the displacement power factor in the line current to more than 0.99 and reduced the output voltage ripple to 4% without any electrolytic capacitor. [ABSTRACT FROM AUTHOR]

SUMMARY: From growing interests in the environment issues, promotion of photovoltaic power generation (PV) is accelerated in the world. Meanwhile, rapid chargers (RCs) for popularized electric vehicles are being installed in urban areas. These two trends in distribution system might cause severer voltage fluctuation problems. On the other hand, a RC can provide the reactive power support, which is capable of voltage regulation. Based on this viewpoint, this paper proposes a new framework of voltage regulation, in which the reactive power compensation by RCs is actively utilized. The proposed voltage regulation method combines two different control functions with consideration for over‐compensation avoidance. This paper ascertains the validity of proposed voltage regulation method through numerical simulations. [ABSTRACT FROM AUTHOR]

SUMMARY: In this paper, a hybrid model of fuzzy clustering and ANN (Artificial Neural Network) is proposed for electricity price forecasting. Due to the complicated behavior of electricity price in power markets, market players are interested in maximizing profits while minimizing risks. As a result, more accurate models are required to deal with electricity price forecasting. This paper proposes a new method that makes use of fuzzy clustering preconditioned GRBFN (Generalized Radial Basis Function Network) to provide more accurate predicted prices. Fuzzy clustering plays a key role to prevent the number of learning data from decreasing at each cluster. GRBFN is one of efficient ANNs to approximate nonlinear systems. Furthermore, a modified GRBFN model is developed to improve the performance of GRBFN with the use of DA (Deterministic Annealing) clustering for the parameters initialization and EPSO (Evolutionary Particle Swarm Optimization) for optimizing the parameters of GRBFN. The proposed method is successfully applied to real data of ISO New England, USA. [ABSTRACT FROM AUTHOR]

SUMMARY This paper examines the influence of aggregated power output fluctuation of photovoltaic power generation system (PVS) on the power system frequency focusing on ramp events of aggregated PVS power output. A numerical simulation model of economic load dispatching control (EDC) and load frequency control (LFC) is used together with a PVS power output forecasting model and a unit commitment (UC) scheduling model developed in our preceding study. As a result, in the case of ramp event with long duration and high ramp rate, the frequency violation occurs when the power output of controllable generators with high load-following capability reaches to upper/lower limit even if the power output of low load-following capability generators is still available. If the load dispatching scheme is tentatively changed from the conventional EDC using an equal incremental fuel cost rule to, for example, a dispatching policy based on the capacity without the consideration of fuel cost, the aggregated load-following capability can be kept, avoiding the frequency violation. [ABSTRACT FROM AUTHOR]

SUMMARY In a distribution line, power system control and power equipment investment are planned based on a measured power system current. However, recently the mass introduction of photovoltaic (PV) make it difficult for us to precisely measure the demand curve that is a current consumed by electrical equipment because the reversal power flow from PV systems is superposed. Therefore, the prediction of demand curves of distribution line is indispensable for power system management. In addition, it is also necessary to estimate the reliability of the predicted values as well as predicted current itself. In this paper, we propose the estimation method of the prediction interval that is the index of reliability based on the past demand curve database. The feature of the proposed method based on Just-In-Time (JIT) modeling make it possible for us to accurately estimate the prediction interval by the normalized database of demand curve. In this paper, some numerical examples are presented, which demonstrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

District Heating and Cooling (DHC) combined with a Cogeneration System (CGS) is one of the most efficient ways to supply energy to the commercial and residential sectors. This paper discusses the feasibility of introducting DHC from the viewpoint of the overall energy saving effect in Japan's energy system as a whole. Although DHC is efficient for congested areas such as urban business centers, these areas are limited in capacity and number. In our evaluation of the feasibility of introducing DHC, we consider the energy demand density profiles of Japan's commercial and residential sectors in order to determine the installed DHC capacity that is optimal for meeting the growth of energy demand. This paper also discusses operating patterns of CGS and of boilers in DHC. In order to improve the efficiency of individual DHC facilities, CGS should be operated so as to satisfy heating demand, resulting in a low annual load factor. On the other hand, the overall efficiency of the energy system requires an improvement of the overall load factor of CGS, which is achievable by combined use of CGS and boilers. Operation of CGS in this manner improves the feasibility of the introduction of DHC. © 2000 Scripta Technica, Electr Eng Jpn, 133(2): 31–42, 2000 [ABSTRACT FROM AUTHOR]