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The integration of solar power, batteries and ultracapacitors to increase the reliability of the power supply for dc-powered data centers and reduce carbon emissions is investigated in this paper. The availability of ultracapacitors that have very high power densities and charge/discharge cycling capability characteristics enable smoothing solar power intermittencies. Four typical weather conditions...
Energy efficiency is considered a critical technical parameter for the performance evaluation, sizing, and design of control strategies of grid-connected battery systems. Therefore, measurement of the energy efficiency of grid-connected battery systems is necessary. In this paper, the experimental evaluation and measurement of the energy efficiency of a small-scale grid-connected NiMH battery system...
Due to the high-efficiency and high-frequency of bridgeless power factor correction (PFC) converter, it gets widely used in many areas, such as IT service power supplies, aerospace power supplies and so on. Meanwhile it concludes many passive components, like two boost inductors, two common-mode (CM) inductors, one differential mode (DM) inductor, two CM capacitors and one DM capacitor, which occupy...
The amount of energy consumed by data centers and telecom buildings is increasing annually due to the buildup and high-density arrangement of ICT equipment, which is needed to handle the rapid rise in traffic brought on by the spread of smartphones and advances in the Internet usage environment. The NTT Group, whose business activities are centered about ICT services, uses approximately 8.5 billion...
This paper presents a supercapacitor prediction aging model according to the voltage and to the temperature for telecommunication applications. To investigate this phenomenon, an experimental test bench is designed to accelerate the supercapacitors' calendar aging. Experimental tests are carried out at constant temperatures when the supercapacitors are polarized at the maximum voltage. To quantify...
The role of the equipment controller is changing in the Software-Defined Network (SDN). In the past, the role of the controller was focused on providing alarms and status information. In the Software-Defined Network, the controller provides the alarming and status with real-time information about the available capacity and historical information about energy use. With the larger role of equipment...
The dc power feeding system has been attracted attention in recent years. Since the load is dynamically changed in this system, the stability of dc-dc converter is important. This paper presents the stability analysis and the transient response of digital integral gain changeable control dc-dc converter using small output capacitance. The proposed method changes the integral gain with a single logarithm...
Aiming to improve energy saving in regard to data centers, the authors have developed a high-efficiency air conditioner for use in data centers. In consideration of application to data centers, which are considered “mission-critical” facilities, development of air conditioners using a refrigerant — which have no effect on ICT equipment even in the event of leakage — has been continuing. A key feature...
All electronic devices on the market have to comply with the valid standards regarding electromagnetic compatibility. This paper presents an efficient holistic procedure to analyze the surge voltage immunity of a modern power supply topology based on the bridgeless boost power factor correction stage. The procedure forms a structured process flow and allows a simple but effective analysis process...
Increasing the energy self-consumption rate is an important challenge for economic improvement in a grid parity environment. Here, the construction of a power supply system that combines solar power generation and a storage battery system is detailed and the increase in the renewable energy self-consumption rate obtained by optimizing the charging and discharging of the storage battery is reported.
A gate drive printed circuit board (PCB) was developed for a 50-mm-wide modular-design thin power unit that uses two double-sided cooled power modules in an uninterruptible power system (UPS). A conventional gate drive PCB has a concentrated gate power supply circuit that uses a large transformer and has a conventional pulse open-phase detection circuit that occupies a large mounting area. Thus, the...
Today's inverters in homes are considered too large for homeowners, although they are typically only the size of a picnic cooler. If they were smaller, one believes that more homes would entertain using them for solar-power, as well as bringing electricity to remote areas of the world where electrical energy is not distributed. The key goal of this project was to reach an inverter power density in...
This paper presents the merits of using low-losses fast-switching, Gallium Nitride on Silicon Enhanced mode High-Electron-Mobility-Transistor cascode switches; in comparison to pure Silicon MOSFET in the DC/DC converter of the Nissan Leaf electric vehicle (EV). The performance of the car, at steady state conditions, is studied to show the technical benefits of using Gallium Nitride on Silicon Enhanced...
This paper presents a hierarchical control framework with power flow controller for state of charge (SOC) equalization of the embedded storage systems among different active power distribution nodes(APDNs) in a communications power plant that uses local distributed generation resources. Communications power plant configured with APDNs can provide numerous advantages in DC enabled microgrids. A multi-input...
Among current research issues of dc microgrids, short-circuit protection is very challenging because of the high rate of rise for the fault currents. Slow-acting electromechanical circuit breakers lead to system overdimensioning resulting in additional costs. Circuit breakers based on power semiconductor devices have the potential of fast interruption of fault currents. Unfortunately, the energy stored...
The differential mode and common mode inductance of two windings located on a magnetic material of toroidal shape are investigated. The field problem is solved by the method of separation and the use of Fourier approximation for fitting the solutions to the boundary conditions. The solution is discussed by means of numerical evaluation for different parameters like magnetic material, width of the...
Over recent years, against a social background of rising energy costs and a desire to create a “low-carbon society,” the demand to reduce electricity consumption has been growing. As for data centers, cooling of IT equipment (like servers and communication devices) by using means like heat-pump systems consumes a large amount of energy. As a means of reducing the electrical power consumed by cooling...
State feedback decoupling permits to achieve a better dynamic response for Voltage Source in stand-alone applications. The design of current and voltage regulators is performed in the discrete-time domain since it provides better accuracy and allows direct pole placement. As the attainable bandwidth of the current loop is mainly limited by computational and PWM delays, a lead compensator structure...
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