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This paper proposes a real time symmetrical coordinate transformation applied for the fault-ride-through when the imbalanced fault occurs in the utility power system. The power conditioner of the photovoltaic system in Japan is required to remain connected when the utility power system fault occurs under certain condition. The most popular fault is 1 line-to-ground fault. The next is 2 line-short-circuit...
This paper introduces the flywheel energy storage system (FESS) in a long lifetime uninterruptible power supply. The first prototype FESS (3.0-MJ) uses low cost ball bearings and general purpose induction motor in terms of cost reduction. From the experimental results, it is confirmed that the charge and discharge efficiency of the FESS is 60.7% (charge 80.7%, discharge 75.1%). In order to improve...
Typical low cost light sensors used in modern day buildings have an error of up to 40%. To achieve intelligent lighting control for intelligent energy management, illuminance sensor nodes need to have less than 5% error. In order to realize such sensors, high accuracy illuminance sensors of error less than 3 % are proposed to be integrated with high resolution Analog to Digital Converters (ADC). Subsequently,...
In this paper, a single-phase self-synchronized inverter that mimics synchronous generators (Synchronverter) without a dedicated synchronization unit is investigated. It offers a mechanism for power systems to control distributed renewable energy sources. It can synchronize itself with the grid before connection and track the grid frequency very well after connection without a phase-locked loop (PLL)...
This paper presents a novel control scheme to control the flow of active and reactive power through a single-phase bi-directional AC/DC converters used for telecom backup systems. The proposed controller enables the telecom facilities to control the power flow in both directions from grid to telecom and telecom to grid. In this paper the fuel cell system coupled with ultra-capacitors has been used...
With the continuous increase of corporate and personal needs of the Internet, the data center industry has entered a stage of large-scale planning and construction. It is expected that in 2015 the national market benefit of data centers will be more than 50 billion. As the business development, the power consumption of data center also increased year by year. But traditional technique and rough construction...
A novel synchronous generator has been developed for wind power generation. The generator does not require slip rings and brushes for field power supply as well as permanent magnets. The field flux is generated by the half-wave rectified excitation method. In this paper, the basic principle is explained. Then a test machine is produced and the performance characteristics are shown analytically and...
A worldwide mobile network has consumed high volume of energy because of its high speed broadband growth (e.g., LTE, LTE-A, and 5G). Wireless telecommunication service providers have strived for reducing an operating expenditure (i.e., electricity cost) because an urban base station (BTS) consumes more power as these data uses of mobile subscribers increase. In order to reduce an operating cost of...
Phase detection schemes whit the purpose of Synchronization has been reviewed in this paper. These techniques include Phase-Locked Loop (PLL) methods such as the Single-Phase PLL (pPLL), Enhanced PLL (EPLL), Quadrature PLL (QPLL) and Synchronous Reference Frame PLL (SRF-PLL) and Adaptive Notch Filtering (ANF). The ANF is then modeled in Simulink and has been tested under distorted input signal and...
The development of wireless power charging radiator for mobile device and its efficiency characterization are presented. The radiator which is designed using a microstrip patch in spiral shape is intended to work at operating frequency around 10MHz. Some investigations over the gap between 2 radiators are carried out to analyse the effect of varied gap separations to the reflection and transmission...
In this paper, the bifurcation criteria of the inductive power transfer (IPT) system are derived. The bifurcation phenomena are analyzed considering compensation topologies and coil losses. The bifurcation criteria are defined as the coupling coefficient k and the bifurcation criteria and split frequency are expressed by the quality factor of coil, loss of secondary coil, load resistance, and switching...
This paper discusses a control method for an electrolytic capacitor-less single-phase AC/DC converter with PFC capability and with constant dc-output voltage. Generally, single-phase AC/DC converters employ bulky electrolytic capacitors in order to smoothen the ripple power with twice the utility frequency. The proposed control method uses a T-type NPC circuit with a small film capacitor and decouple...
An accurate circuit and device model is a valuable tool for developing new topologies, building successful designs, and shortening time to market. The input, output, and reverse transfer capacitance of power MOSFET are of vital importance to the MOSFET as they determine the dynamic behavior of the device during switching transients. In this study, the static characteristics of a specific GaN device...
This paper describes lateral misalignment characteristics of electrical resonance coupling wireless power transfer (ERC-WPT) from experimental points of view. A dead zone is an important factor for ERC-WPT because ERC-WPT cannot transfer electric power in the zone. Electrical coupling units that are composed of 2 electrodes lined up laterally have a dead zone. The dead zone exists near outer edge...
This paper proposes an isolated DC-DC converter for Power-Supply on chip (SoC) realized by the couple of air-core coils. The pro-posed isolated DC-DC converter is evaluated by numerical simulations and experimental results. The fabricated prototype DC-DC converter works well and the simulation results are good agreement with experimental results. This paper also discusses the potential of proposed...
Wireless Power transfer using electric field can realize highly efficient electrical power transmission and the transmission units are thin and light. However, the transmission system produces large electric field intensity and the electric field noise can make other electronic devices malfunction. A shield box is greatly effective to reduce the electric intensity 60dB without a decline of transmission...
In this paper, we propose a new power peak shifting system that uses demand forecasting. The study is based on the assumption that a dynamic pricing system has been introduced to an office equipped with a data center. In addition, we report on the results of simulations that show our proposed peak shifting scheme improves system utility and strength through increased economic efficiency, even when...
This paper presents a comparison of dissipation between LLC and phase shift converters under the same size condition using a manufactured power supply. Moreover, it is clarified that the ratio of the transformer dissipation for the overall dissipation of LLC is much higher than that of the phase shift converter. In addition, we show that the winding resistance decreases by improving the coupling between...
Telecommunications is a rapidly growing field in global technology and it has a significant social, cultural, and economic impact on modern society. As such, ensuring reliability of these systems should be highly prioritized and involve sophisticated standards. Due to the highly sensitive nature of Telecom loads, it is vital that failure of the utility power be detected quickly. In this paper, Slip...
Recently renewable energy has attracted a lot of attention and solar power generation systems and wind power generation systems are widely used as public eco-awareness increases. Generally inverters are used in such power generation systems. They need high efficiency. Multi-level technique improves efficiency of inverters.
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