Due to a continuously increasing power demand of computer–network server equipment, power supply manufacturers are faced with requirements for ac/dc server power supplies with significantly higher power densities. In this paper, circuit technologies and optimization techniques that are suitable for meeting these new power-density requirements are discussed. The focus of the paper is on single-p...

This paper proposes a parallel energy-sharing control for fuel cell electric vehicles (FCEVs) application. The hybrid source consists of a fuel cells (FCs) generator, battery packs and Ultracapacitor (UC) modules. In the proposed parallel energy-sharing control, each source is connected to the direct current (DC) bus via power electronics converters. A total of six control loops are applied in ...

In this paper, a 3-phase active power filter (APF) is presented to eliminate harmonics and to compensate the reactive power of an uncontrolled rectifier with capacitive loading taken as non-linear load. An APF is realized using 3-phase voltage source inverter (VSI) with dc bus capacitor. Reference source currents are estimated using P-I control over dc bus voltage and 3-phase source voltages. C...

Multilevel inverters are suited for high power drive applications due to their increased voltage capability. Specifically, as compared to three level inverters, for a given dc bus voltage, a four-level inverter is able to synthesize better waveforms with reduced device ratings. In a medium voltage drive, a conventional diode bridge rectifier is a low cost multilevel solution if the dc bus volta...

A state-of-the-art Chinese fuel cell city bus, using a hybrid power system is proposed. This comprises a proton exchange membrane fuel cell and Ni/MH batteries to combine the high energy density of fuel cells with the high power density of batteries. A dc/dc converter is placed between the fuel cell and the battery to control the electric power flow. This paper presents a novel control strategy...

A novel pulse-width modulated (PWM) single-phase line-interactive uninterruptible power supply (UPS) based on the small dc bus capacitor is presented. The proposed system is made up of an ac chopper which includes a diode rectifier, a boost switch, a charger and an inverter. It has the features of a small dc bus capacitor, small input and output inductors, and low switching loss, and is very su...

This paper proposes an analytical approach to derive voltage gain for phase modulated (PM) dc-dc series resonant converter (SRC) operating in discontinuous conduction mode (DCM). Conventional fundamental harmonic approximation (FHA) technique is extended for non-ideal series resonant tank. The DCM analysis is presented in a normalized form defining appropriate base quantities. The converter is ...

Many existing protocols indicate that full utilization and fairness might be incompatible in high-speed-high-latency MANs or LANs. The purpose of this paper is to study the fundamental limitations of dual bus networks, in terms of full utilization, fairness and bounded access delay. A new protocol called FUFA (fully utilized and fair) is used to demonstrate some of these basic properties. We de...

In this paper, a new control of the DC–DC power converter that interfaces fuel cell (FC) system with DC bus photovoltaic (PV) is proposed to increase battery lifespan by its operating in charge-sustained mode. Thus, variability PV and load demand compensated FC generated considering flows balance on bus. During peak power, if exceeds demand, then excess will an electrolyzer. The operation as ba...

This paper presents efficiency analysis of the power buffering in common voltage bus systems. Operation of the power buffering is briefly described with the power control experiments. The efficiency measurement setup and performed measurements from the charging and discharging events of the ultracapacitor module with the dc-dc converter are presented. As a result, the efficiency map of the dc-d...