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The performance of dc–dc converters plays a vital role in the exploitation of renewable energy sources such as solar and fuel cell (FC). This paper demonstrates the feasibility of using the input/output (I/O) magnetically coupled interleaved buck–boost converter, improving the conventional interleaved cascaded buck–boost converter in FC applications. While keeping the same step-up/step-down voltage transfer ratio, the proposed topology facilitates operating conditions with its nonpulsating I/O currents and high efficiency using interleaved technique and reducing switches' voltage stresses, respectively. The steady-state operation of the converter is analyzed based on the state-space-averaging method and supported with simulation results. The prototype setup of 360-W and 36-V output voltage for an FC with a brand of “FCgen 1020ACS” Ballard Power Systems, Inc. was implemented. Experimental results are presented to verify the theoretical expected merits of the converter, including high efficiency and nonpulsating I/O currents. [ABSTRACT FROM PUBLISHER]

Dynamic behavior of DC–DC converters plays a crucial role in stability of renewable energy exploitation systems. This paper presents small signal modeling of an input/output magnetically coupled interleaved buck–boost converter for fuel-cell applications to help the designers with the better understanding of converter dynamics. Aiming to have a continuous converter transfer function for a smooth transition between the operation modes and an improved inner dynamics, a damping network and an input/output coupling have been added to the interleaved structure of well-known cascaded buck–boost converter. Having the same step-up/step-down voltage transfer ratio, smooth transition and improved inner dynamics make this converter quite suitable for renewable energy applications. The paper presents a small signal ac equivalent circuit model of the proposed converter based on state space averaging (SSA) method. Simulation results show remarkable improvements in converter dynamic behavior in both time and frequency domains. Prototype setup of 360 W and 36 V output voltage for a fuel cell with a brand of “FCgen 1020ACS” Ballard Power Systems, Inc. was implemented. Experimental results are presented to verify the theoretical model and its expected merits. [ABSTRACT FROM AUTHOR]

Abstract: Having a voltage transfer ratio lower than unity with a 0.866 upper limit, even lower than 0.866 in the course of experiments because of parasitic components of real power circuits, is one of the shortcomings of matrix converters. This deficiency is one of the greatest impediments to industry adaptation of matrix converters. To surmount this barrier this paper proposes a novel modification in circuit topology of indirect matrix converters (IMC) achieving voltage boosting and unity voltage transfer ratio. Besides preserving the inherent advantages of the conventional matrix converters, such as controllability of input power factor, sinusoidal input/output currents and the ability of bidirectional power flow, the remarkable feature of this solution is that, unlike the other research in this field no special control strategy or additional reactive elements at the DC-link is used and the integrity of the converter has been kept as much as possible. Furthermore a new efficient switching strategy is proposed for the new converter. Simulation results are shown to support the given theoretical analyses and experimental results obtained from a 5kW converter verify the full functionality of the proposed topology. [Copyright &y& Elsevier]

Abstract: This paper describes an average model of indirect matrix converter (IMC) with an output LC filter in stationary and rotating reference frames. The developed model is non-linear and should be linearized in order to design linear controllers. Transient performance of the IMC is compared with that of conventional inverter in classic AC/DC/AC system. In order to make the IMC applicable for power conditioner applications a synchronous controller is designed. A power conditioner acts in one or more ways to deliver a voltage of the proper level and characteristics to enable load equipment to function properly. In order to afford the power conditioner requirements the controller has two segments. One segment controls the IMC with balanced input supply voltage and the other controls the system with unbalanced input supply voltage. The system can provide balanced output voltages with slight distortion of line side currents. Theory analyses, the model validation and simulation results are presented to verify the effectiveness of this control method. [Copyright &y& Elsevier]

In this paper the role of the voltage vectors of a two-level converter on variations of active and reactive power of a Doubly Fed Induction Generator (DFIG) is studied more deeply. Previous approaches only have a qualitative look toward this issue that consequently, leads to extraction of an optimal switching table. With expanding accurate equations describing the variation of active and reactive power, this paper is going to inspect the role of the voltage vectors in active and reactive power control of a DFIG exactly, and to illuminate thoroughly the impression of terms like rotor velocity and load angle variation, neglected in the previous works. Expanding these equations provides the ability of scrutinizing the effect of the converter voltage vectors on active and reactive power of the machine at any operating point. This leads to achievement of a more accurate and optimal switching table. The distinction of this method accounts it as a good candidate for online methods to predict the effect of each voltage vector on active and reactive power variation. [ABSTRACT FROM AUTHOR]