The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Since the Great East Japan Earthquake, everyone has come to review how to use electric energy. In addition, people who say that it should aggressively install safe and clean energy system have increased. To create city which is learned from nature, supported by science and technology, we started activity of community in Fukuoka and Yokohama. And the distributed energy system will be key function at...
This paper proposes state-of-charge (SOC) and remaining charge estimation algorithm of each cell in series-connected lithium-ion batteries. SOC and remaining charge information are indicators for diagnosing cell-to-cell variation; thus, the proposed algorithm can be applied to SOC- or charge-based balancing in cell balancing controller. Compared to voltage-based balancing, SOC and remaining charge...
Generally, the way of 0.1C current fully discharge battery capacity measurement, which is required for 10 hours discharge during this process, is time and energy consuming. This paper is to introduce a new method to measure battery capacity accurately in shorter time. This new method will use the technique of multi-frequency measurement for battery during discharge. This measurement will eventually...
This paper is based on the current situation of Chinese telecommunications network infrastructure, propose the technical solutions of power expansion, tenants expansion, tenants management, battery expansion and battery hybrid use management in the sharing and co-construction power site, the management methods of independent charged, independent discharging and hybrid use for different batteries and...
This paper presents a random frequency hopping with triangular ramp control for harmonic reductions in a dc-dc converter. The relationship between “the sawtooth and triangular ramp signals” and the inductor current is analyzed, and the two ramp signals are implemented into the converter to compare the variation of output voltage. When the switching frequency hops, using triangular ramp keeps the small...
This paper presents analytical expressions of the class-E inverter to satisfy the class-E ZVS/ZDS conditions, taking into account the effects of the MOSFET nonlinear gate-to-drain and nonlinear drain-to-source parasitic capacitances. A design example is given along with the PSpice-simulation and experimental waveforms at 2.0 W output power and 4 MHz operating frequency. The waveforms obtained from...
This paper proposes a bypass transfer method without parallel feeding between utility power line and uninterruptible power supply (UPS). This system has ACSWs consists of a bi-directional thyristor and a magnetic contactor both utility power line and UPS line. The control board observes the condition of utility power and UPS to operate ACSWs. A proposed method has instantaneous interruptible period...
The present study discuss about restructuring in lighting systems in order to improve load leveling. The aim of this paper is to perform an economic assessment of utilizing DC lighting instead of AC lighting in presence of photovoltaic energy systems. For each scenario, the amount of luminous flux (lm) provided by the lighting fixtures is constant based on requirements for office spaces. The current...
The output voltage characteristics of a thermoelectric generator were analyzed to suppress heat leakage for low-temperature waste-heat thermoelectric generation. The experimental results show that the pre-cooled thermoelectric device output a higher voltage than the reference device. The experimental results also show that the influence of heat leakage took a longer time to appear using the pre-cooled...
A small modular unit for a power converter system with long lifetime DC-link capacitors is proposed. To reduce the ripple current stress of DC-link capacitors and to improve their lifetime by limiting temperature rises, low phase-to-phase-impedance busbars are selected. Consequently, in a power converter system whose size is 101 L, operating at a rated power of 100 kVA, DC-link capacitors achieve...
In order to charge electric devices such as laptop PC and smart phone without using AC adapters, a simple and low cost DC outlet using a multi-output current resonant converter is proposed. In this method, three level voltages of 5V, 10V and 20V are simultaneously provided in parallel to the DC connector pins. Due to the input terminal of the receiving electric devices only has the desired voltage...
Smart grid encompasses a variety of tools, techniques and technologies that will allow energy suppliers to more accurately measure electricity flows and remotely control each point of the transmission and distribution network using two way digital technology. In this paper, determine the optimal level of automation in distribution networks with local remote control switches and VIT switches automation...
This paper proposes a synchronous rectification (SR) control scheme for LLC resonant converter by digital controller. In the proposed SR control scheme, conduction detector circuit senses the drain-source voltage of secondary SR switches to detect the state of paralleled body diode. Digital controller tunes the turn-on and turn-off time of SR switches depending on conduction detector circuit output...
This paper presents a current sensor-less boundary current mode PFC converter. In particular, the ac-dc converter with a boundary current mode control has the following several advantages. One is that it has the capability to achieve the low input current distortion and the unity power factor can be obtained in theory. Another is that it is possible to reduce the switching loss because the inductor...
This paper proposes a PFM+PWM hybrid controlled soft-switching half-bridge converter which has both benefit of conventional half-bridge converter and LLC converter. Generally, conventional half-bridge converter has good constant current characteristic due to PWM control, however it has some drawbacks of (1) primary side switches and secondary side diodes operate under hard switching, (2) two magnetic...
A single-stage ac-dc converter consisting of full-bridge converter is proposed for EV charger applications. The proposed approach is superior to conventional two-stage ac-dc converter widely used for EV charger applications. The two stage ac-dc converter is apt to be costly and large. However a single-stage ac-dc converter is suitable to a low cost, small volume due to a reduced number of components...
In this paper, the efficiency limits of power electronic converters are investigated from a semiconductor point of view. The approach is presented on the example of a hard switching half bridge while taking Si, SiC and GaN devices into account. Beside parasitic effects of the semiconductors itself, further converter non-idealities and limits from a thermal point of view are discussed. All in all,...
The facility cost of the storage systems are a critical issue in the construction of micro grid, which is the core of the renewable energy. We propose the direct current mutual power interchange system as a way to reduce the storage battery capacity. This paper reports the outline of the proposed system and the verified result on the effect caused by electricity interchange upon the reduction of battery...
Energy storage system is used in power-grid to compensate for the power fluctuation caused by renewable energy systems. This paper presents loss-analysis results of power converter utilized for the energy-storage systems. The system has multiple energy storage devices such as a LaB and an EDLC. This paper discusses two methods to distribute the compensation power reference to each device. Conventional...
Droop Control has been a well-established control technique both in AC and DC power distribution grids for many years, because it provides a simple way to equally distribute the load current between remote power sources. With the increasing demand for low voltage DC microgrids supplying high-reliability equipment, like servers in data centers, to work both grid-tied and autonomously without a connection...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.