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.
In recent years, dc power supply system has been increasingly attracting attention, because a solar power system and a storage battery trade their power by dc. A concept of HVDC Tap (High Voltage DC Tap) is known as an interesting method to build the dc power supply system. However, the circuit causes a high voltage ripple on the dc line and its transformer is afraid to be saturated by a dc bias magnetism...
In recent years, there is growing interest in improving lithium-ion battery state monitoring. This is due to growing concern over ensuring reliable and safe operation of lithium-ion based energy storage system especially in automotive and stationary e.g. UPS in data center applications. In this paper, battery state of charge estimation based on Extended Kalman Filter (EKF) and improved battery model...
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...
A battery management system (BMS) is a system that manages a rechargeable battery (cell or battery pack), by protecting the battery to operate beyond its safe limits and monitoring its state of charge (SoC) & state of health (SoH). BMS has been the essential integral part of hybrid electrical vehicles (HEVs) & electrical vehicles (EVs). BMS provides safety to the system and user with run time...
This paper proposes a design method of a common-mode current feedback type EMC filter in an interconnection system. First, the relationship between the switching frequency of the PWM inverter, the common-mode feedback current and the volume of the filter reactor is theoretically estimated. Moreover, the switching frequency and the current capacity of switching devices which are necessary in order...
BTS sites are subject to constant cost pressure. Operational cost and especially Diesel consumption form ever increasing cost components. Here, photovoltaics (PV) is an effective measure to cut down operational cost and emissions for hybrid BTS sites. Often PV is integrated in a non-optimal way opening up room for improvements to the operational management. Three different advanced PV-hybrid operational...
This paper presents a novel zero-crossing point detection method for boundary current mode PFC converter. In the conventional boundary current mode, the zero-crossing point is detected by observing the inductor voltage. When the digital controller is used in the conventional method, the detection of the zero-crossing point is delayed due to the delay time caused by the processing of DSP. And the detection...
This paper introduces a highly-efficient two-stage DC-DC converter with wide input voltage. Based on the digital control technology, it uses two-stage DC-DC conversion. This paper describes the circuit topology, working principle and control method of the convert in detail. The converter consists of the former input circuit, intermediate conversion circuit, output rectifying circuit and feedback control...
The common mode (CM) noise mechanism of totem-pole bridgeless PFC converter is analyzed in this paper. The conducted noise performance of a bridgeless totem-pole PFC converter using GaN HEMTs is investigated under experimental conditions: 230V ac input, 390V dc output, and 50kHz switching frequency. The CM noise located around the input voltage zero-crossing of the converter is noticed to be significant...
More effective electrical energy production requires more attentions to storage technologies. This paper analysis and compares different electrochemical energy storage technologies, in the terms of energy/power density, specific energy/power, efficiency, lifespan, cycle life, capital energy/power costs, scale, application, technical maturity, as well as environmental impacts. The pioneering countries...
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...
For IT data center and high voltage UPS applications, selecting a lithium-ion (Li-ion) backup solution for a critical standby power source can help users to benefit from a reduced installed footprint, optimized total facility energy and a reduced environmental footprint when compared to conventional battery solutions. Backup systems utilizing high power Li-ion cells offer the ability to significantly...
Demand for reliable, efficient mobile network services is increasing, as customers seek for more value-added services (VAS) from telecom operators. However, many operators still suffer from network outages as they do not have solutions in place that will detect and alert them of a problem even before it escalates. Network outages can be prevented through a comprehensive, intelligent monitoring system...
A current sharing method considering battery state of charge(SOC) for multi-module uninterruptable power supply(UPS) system is proposed. Modularized UPS system consists of a single master module and multi slave modules. A master module performs output voltage control and distributes current commands to slave modules. The current commands are generated by using the proposed current sharing algorithm...
In this paper, stability analysis of a typical DC/DC Boost converter feeding a Constant Power Load (CPL) with and without a Battery Energy Storage (BES) is discussed and explained. CPLs, usually, cause instability issues for DC/DC converters due to their negative impedance characteristic. The state-space averaged model analysis of the converter is performed and stability regions of the converter while...
This paper proposes a current-fed two inductor bi-directional DC-DC converter using resonance (CF-TIBCR). The power losses of CF-TIBCR mainly occur in switches, especially the low voltage side switches. To improve the efficiency, the detailed loss analysis of switch and magnetic components is performed from the steady state analysis and operation principles. To verify theoretical loss analysis, it...
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...
DC 380 V power supply has begun to be used for data centers to save energy and supply high quality power. This paper describes dc capacitor voltage regulation of ac-dc converter using Modular Multilevel Cascade Converters based on Single-Star Bridge-Cells (MMCC-SSBC) without line frequency transformer. The proposed voltage regulation method compares each dc capacitor voltage with the reference value...
The power conditioning system (PCS) is widely used as a grid connected inverter to keep output constant. A novel power conditioning system (PCS) using a circuit of modular multi-level converter (MMC) construction is investigated. The feature of the system is that output voltage becomes multilevel for low distortion and circuit has an energy storage system such as a battery or an electric double layer...
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.