This paper deals with designing and sizing of a Multiple-Input Power Electronic Converter (MIPEC) to be used in an electric vehicle propulsion system that includes a fuel cell (FC) generator and a combined storage unit. The combined storage unit is composed by an ultracapacitors tank (UC) and a battery unit (BU). MIPEC is responsible for power-flow management on-board the vehicle for each mode of operation. Specifications for MIPEC designing come out from many considerations concerning traction drive and reference driving cycle, on-board power source and storage unit characteristics. However, to date sizing and configuration of both storage units and on-board generators are directly related to traction drive and driving profile (i.e. vehicle performances and characteristics) and no relation with power electronic interface is considered during preliminary design. Then, power electronic interface is selected in order to fit traction drive requirements with power source and storage unit characteristics; as a consequence converter mode of operation lacks of optimization, as well dynamic behavior and efficiency cannot be maximized. In this paper, MIPEC design and power source and storage unit selection are achieved at the same project stage according to traction drive requirements. Experimental results on 60kW power electronic interface are presented

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This study deals with a newly-conceived voltage control method for three-phase four-leg voltage source inverters\ud (VSIs) which are being required in autonomous power generating units devoted to supply both three-phase and single-phase electrical loads in four-wire electric power distribution systems. To deal with VSI operating conditions providing three-phase voltage supply of both unbalanced loads and non-linear loads, an integral + resonant (I + R) voltage control structure is discussed and experimentally verified by means of a 25 kVA rated power converter prototype. It is shown that the proposed voltage control allows simplifying the overall control configuration, achieving zero-overhead power factor regulation and fast compensation of load unbalances. Further to that, a complete current limiting strategy is described and tested under different load conditions

International Standards impose to Distributed Energy Resources, connected to the grid by an inverter, to detect an islanding condition within a suitable time interval. In this paper a Phase Locked Loop (PLL), based on a third-order prediction-correction filter, is proposed to implement an islanding detector with reduced detection time. Such a feature is obtained using the estimation of the grid angular frequency and acceleration provided by the PLL with a negligible time delay. The proposed approach is implemented on an industrial grade DSP and validated through the experimental comparison among different detection methods, such as Rate of Change of Frequency (ROCOF) and Slip Mode frequency Shift (SMS). The combined use of ROCOF and SMS is also illustrated and discussed.