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This paper presents a novel and reliable DC switch and DC socket for high voltage DC power feeding system, in which the arc does not occur when the are turned on/off and inserted/removed, respectively. The novel prototype DC switch and DC socket have been made. Both are almost same circuit configuration and operation principle and then composed of two mechanical relays and a single MOSFET. It has...
Quantitative analysis of the output current for the multiphase buck converter facilitates the optimal design of the converter. This paper quantifies the output current and its ripple cancellation effect. A universal formula has been derived to express the output current of multiphase buck converter with any number of phases operating at both continuous conduction mode (CCM) and discontinuous conduction...
The purpose of this paper is to present a digitally controlled dc-dc converter with a novel peak current injected technique. In the proposed method, the peak current is able to be detected by using a voltage controlled oscillator (VCO) which is very low cost and the simple delay circuit implemented by the a field programmable gate array (FPGA). As a result, it is confirmed the main switch is turned...
This paper addresses the reliability and availability of uninterruptable power supply systems (UPS) used in modern datacenters and telecom core infrastructure. As 380V DC power distribution systems are gaining wider acceptance, it is expected that they meet high standards imposed by the industry in terms of reliability and availability. In this paper, reliability and availability of AC UPS topologies...
This paper presents a new analysis methodology to quantify the output current and output capacitor ripple current for the interleaved boost converter with an arbitrary number of phases operating in both continuous conduction mode (CCM) and discontinuous conduction mode (DCM). As the result, all the possible output waveforms of the output current are presented. This analysis result can be used as a...
The purpose of this paper is to present a new digital control switching power supply for the HVDC system in data center. The two stage converters are proposed to address the problem of input voltage drop. It consists of the boost converter and the phase-shifted full bridge converter. Since the first stage boost converter make the output voltage constant, good regulation characteristics against the...
Uninterruptible power supplies (UPSs) are widely used to overcome instantaneous voltage drops and complete power failures. This paper proposes a novel single-phase standby UPS with a small size and high reliability. The proposed UPS consists of a buck-boost converter and a full-bridge inverter; this device eliminates the need for bulky electrolytic capacitors or output LC-filtering. The buck-boost...
This paper reports test results and reviews for the developed plug and socket-outlet applied to the 400 Vdc power systems expected to improve energy efficiency in communication sites, data centers, commercial buildings, and smart energy systems. However, there are some safety issues to use 400 Vdc power. The plug and socket outlet has a unique mechanism based on combination of a permanent magnet and...
This paper proposes a method for reconstructing the three-phase voltage output of a current source inverter (CSI). The method produces a three-phase voltage by using the DC-link voltage and the switching pattern of the CSI and improves the reconstructed waveform by using the delay time of a filter. The proposed method can reduce errors between the actual voltage and the reconstructed voltage at the...
The low input current ripple and high efficiency are two of the most important criteria for the interleaved boost converter interface in Photovoltaic / Fuel Cell Power Conditioning System. This paper analyzes the input current ripple of the interleaved boost converter and its effect on power loss from the view of a practical design. Therefore, design considerations of the input current ripple minimization...
Data centers (DCs) are considered critical loads that require premium power from utilities to ensure reliability at all times. Microturbine (MT) generation systems are becoming important in DCs, not only as distributed generation (DG) for supplying electricity, but also for providing cooling and heating functions, which is known as combined cooling, heat and power (CCHP) or tri-generation. This paper...
While the speed of operation of conventional circuit breakers for equipment (CBE) is suitable for the majority of modern day equipment applications, ultra-sensitive solidstate circuitry typically found in telecom power distribution applications will often require faster switching protection under overcurrent conditions than electromechanical CBEs can achieve.
This paper presents a reconfigurable solar photovoltaic (PV) battery charger. A traditional PV charger either utilizes a DC/DC converter between the PV array and load, or it connects the battery directly to the PV array without any power conversion. Different from these approaches, our proposed PV charger avoids conventional DC/DC converters by using a reconfigurable switch matrix. This switch matrix...
The principle of full-bridge DC-DC converter is briefly expounded, including the two typical control methods, named limited dual polarity hard-switch control and phase-shifted soft-switch control. Then the common mode noise equivalent circuits of full-bridge DC-DC converter are deduced, taking the common mode noise of the bridge leg's midpoint into account, and the difference between the two typical...
This paper describes an algorithm for managing a system consisting of “dissimilar” battery packs in parallel without multiple DC/DC converters interfacing each battery pack to the load. The power loss from the circulating current can be avoided so that the operating time of the parallel battery system is prolonged. The proposed algorithm is able to recognize the load demand and determine the number...
This paper presents new simple control techniques for single-phase five-level Pulse Width Modulation (PWM) inverter. The proposed control technique requires only driving two high frequency switches with maintain other switches at line frequency. Operational principles with switching functions are analyzed for the two techniques. A comparison between the two proposed techniques has been done based...
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