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For development of inductive coupled wireless power transfer (WPT) systems, it is important to consider the overall efficiency of the WPT systems, where the overall efficiency is expressed as the product of the transmission efficiency of coupling coils and the power-conversion efficiency of power converters. Additionally, there are mutual dependencies between coupling coil parameters and power-converter...
In recent years a growing attention is being paid towards energy efficiency in civil and industrial applications. In order to achieve better efficiency and enhance the energy management strategies, better knowledge is needed on the characterization of energy consumers. Categorization of electrical consumers through clustering procedures has been widely addressed in the literature. However, the categorization...
In the field of wireless power transfer technologies, the improvement of transmission efficiency is one of the critical issues. It is important to understand how much power loss is imposed in which areas of a wireless power transfer system in the development phase. Since the transmission characteristics change according to ambient conditions, a measuring instrument capable of observing electric power...
To reduce the life cycle cost of solar power plants, high conversion efficiency for inverters is necessary. The advantages of SiC MOSFETs include not only lower conduction loss but also the ability of high-speed switching. Lower switching loss is derived from high-speed switching. Especially with SiC MOSFETs, the tail current and switching recovery loss can be drastically reduced compared with Si...
The purpose of this paper is to present a performance characteristics of digital current detector in dc-dc converter. The digital peak current mode control dc-dc converter using the voltage-controlled oscillator (VCO) has already proposed. The peak current is detected by using VCO in the proposed method. The gain of amplifier in the current detector affects to the input voltage range of VCO. Also,...
A surge protective device (SPD) is used in low-voltage power systems to protect electrical equipment from surges induced by lightning. An SPD has a drawback that its impedance becomes low in case of SPD failure. This failure can cause not only the SPD, or other devices near it, to catch fire or make an upstream over current protection device (OCPD) operate unnecessary, and also can cause serious damage...
Supply of power is an increasing cost factor in the operation of base transceiver stations (BTS). Selecting the optimized power system for a set of site requirements is key to minimize total cost of ownership (TCO). In this paper we show how dimensioning of a power system through combined technical and commercial simulation helps to optimize the system configuration. The savings on fuel and diesel...
The Wide-Area Control and Operation System for stabilizing renewable energy generations utilizing averaging effect was proposed to reduce capacity of battery energy storage system and a demonstrative project supported by Ministry of Environment of Japan was conducted in order to verify effects of the proposed system. In this paper, concept and configuration of the system are introduced and verification...
This paper proposes droop control for Multi-Level Virtual Conductor (MLVC). This control method aims at overcoming the problem that circulating current flows when MLVC constitutes a mesh connection. Generally, the voltage difference between the terminals of any conductor is zero volts. However, MLVC can keep the voltage difference between the converter terminals constant at a certain value. In this...
This paper presents a simple and low cost PV simulator using diode characteristics for development of PV system. In order to reproduce characteristics of PV module, instead of huge digital data of I-V characteristics of PV module considering temperature dependence, a real diode is used in the proposed system. A low cost microcontroller that has a little amount of data memory is used to control the...
We developed and field-tested an electric vehicle quick charger (EVQC) with storage battery to suppress the lengthening of charging time while preventing a rise in a building's peak power usage caused by EV charging. This EVQC features a demand control technique that determines the amount of power to be used by the charger according to the amount of power used by the building. In addition, charging...
This paper presents a current sensor-less hysteretic current mode switching power supply. Switching power supplies are controlled in the voltage mode or the current mode. The current mode converters are used in the power system which requires of high reliability because it has high stability of the feedback loop compared with the voltage mode converter. The current mode converter is necessary to detect...
This paper proposes a new Space Vector PWM (SVPWM) method for reducing the neutral point potential variation of the three-level V-connection inverter. In the proposed method, by selecting the vectors which has low neutral point potential variation to generate the output voltage command value, the neutral point potential variation of the V-connection inverter can be reduced. In addition, the neutral...
One of the important design issues of smart green buildings is to make use of energy, water and other resources efficiently. Improving the energy efficiency of buildings is an important step towards a more sustainable lifestyle, leading to significant cost savings for the residents. Wireless sensor network will be responsible for the majority of the growth in smart green building systems over the...
This paper proposes a modified 4-phase interleaved converter for the FC power source for mobile based station applications. The ripple and harmonic content of the FC current is one of the various phenomena influencing FC lifetime. The main objective of this research is to minimize inductor size, capacitor, current/voltage ripples, and harmonic content. The main contribution is to presents a control...
We discuss the conduction modes of conducted disturbance from power-conditioning systems (PCSs), which are used for effective utilization of renewable energy, by measuring the voltage at the DC input and AC output ports of three PCSs. By using three different PCSs, which have different circuit characteristics, as equipment under test and using a voltage probe and artificial mains network as the measurement...
Cylindrical large formatted lithium-ion-battery “CH75” cells, battery pack “CH75-6” for stationary use, energy storage systems utilizing the CH75-6 to be applied to industrial applications and these characteristic points are described. In particular, energy storage systems for frequency-regulation applications and the cooling design of the battery panel are described.
The prototypes of the appliance coupler for 400 Volts direct current power distribution system have developed and evaluated. Arc extinguishing and electric shock prevention functions are adopted for safety. Evaluation of load switching is performed with the prototypes and enough capability of arc extinguishing were observed. The prototype was made for confirmation of functions. So that, the shapes,...
The purpose of this paper is to present the digital peak current mode phase-shifted full-bridge zero volt switching dc-dc converter for the data center in the higher voltage direct current (HVDC) system, and show its transient response. The proposed peak current mode control circuit is composed of the RC integrator and comparator only and can detect the peak current in real time. At first, the basic...
To promote the widespread use of HVDC power supply systems, this paper proposes high-efficiency downsized power conversion (380 V to −48 V) equipment for HVDC use having a size small enough for mounting in the dead space of a rack and describes its performance. Configuring 380 V/−48 V conversion equipment with existing technology lowers the efficiency of the entire power supply system and increases...
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