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In this paper, a 500 W, 400 V to 48 wireless power transfer system for vehicle battery charging is analyzed, designed and implemented. Series-series resonant topology is used due to ease of analyze and control. The secondary bridge rectifier is replaced by a sync rectifier consists of four MOSFET in a full bridge configuration in order to reduce conduction losses on rectifier. An efficiency of 92...
Each year, the highest costs in Telecom network shelters and cabinets are not related to personnel or construction, but to energy consumption. The highest proportion of energy costs derive from the energy consumption of electronics cooling units, which run around the clock to ensure well-balanced running temperatures for the enclosed electronic equipment. Technologies designed to reduce energy emissions...
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...
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...
The purpose of this paper is to propose a new control method of wireless power transfer system that can maintain stable power supply even when the positions of the primary and secondary coil or distance between the two coils largely change. The new method will be done by adjusting the switching frequency to a frequency that can obtain the desired output. We confirmed the effectiveness of new wireless...
With a growing concern over environmental issues, smaller and more energy efficient electronic devices continue to draw attention. Usually, high frequency has more advantages in making switching power smaller. A number of suppliers have already launched single-output power (single or double-digit W) which can be operated in high frequency (higher than 500kHz.) Despite increasing demand for multi-output...
In the absence of sources of rapidly varying field, the study of the potential distribution determined, in a linear medium, by a geometrically complex grounding may be conducted by applying the method of superposition of the effects, known as method of subareas of Maxwell. Such approach can be usefully employed in an educational tool intended for students of electrical engineering.
Increasing IT demand has put pressure on the data center, prompting managers and operators to rethink their approach in responding to business needs. Today, IT, telecommunications and data center managers are recognizing the value of integration, both in their IT and communication stacks and in the facilities that support them. Designing, configuring and fabricating data center or telecommunication...
In this paper, an analytical expression for the DC bus harmonics on the input capacitor, caused by a three phase pulse width modulation (PWM) inverter of a high speed motor drive system, is derived. As the result, we found that the parasitic line inductance between the battery and the input capacitor, and the input capacitor are indirectly proportional. We can achieve the calculation method of the...
Lead acid battery is the most popular as a backup power source for communication services. It's very rare, but there is a possibility of electrolyte leakage from inside of lead acid batteries by such as manufacturing defects. If leakage from battery occurs, a ground fault accident occurs, and may cause serious accidents. Since communication service is one of a key infrastructure in our life, it is...
Intermediate Bus Architectures have been popular in the telecom industry for their ability to easily accommodate a wide variety of loads from the telecom industry's common 36–60V distribution voltage range [1]. A key performance metric of telecom power systems is based on the performance of the bus converter used to enable this architecture. While point-of-load converter performance is mostly driven...
NTT Facilities has studied a degradation prediction technology for Valve-Regulated Lead-Acid Batteries which makes use of data obtained from a lead storage battery management system. This paper reports functions and effectiveness of the degradation prediction technology.
Resonant power conversion is an effective technology for various applications. This paper presents a resonant magnetizing approach, aimed at improving the low power density and cost issues of traditional capacitor-discharged impulse magnetizer. In the method, a resonant tank is established by a series capacitor and inductor. Then, by periodically switching power transistors inside the circuit, the...
This paper presents the analysis and design of an inductively-coupled wireless power transfer system implemented using a three-coil arrangement and the Class E2 resonant DC-DC converter. The three-coil structure is modeled using FastHenry simulation software. The theory of reflected impedance is used to determine the optimum operating conditions. A practical application having an output voltage of...
This paper proposes a high frequency switching active clamp flyback converter which can reduce the height of the transformer and the size of the power supply. This is accomplished by applying an adequate resonance voltage lower than the absolute maximum rating of the drain to source breakdown voltage of the switching device. By using this approach we succeeded in reducing the height of the transformer...
Modular UPSs have more than ten years of history, and have been widely used in large data centers thanks to their features of high availability, high scalability, easy maintenance, high efficiency, and many other advantages. The reliability of a modular UPS primarily depends on the system architecture design which should be simple and decoupled to avoid single points of failure. Key parts such as...
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,...
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...
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