An off-board dc fast battery charger for electric vehicles (EVs) with an original control strategy aimed to provide ripple-free output current in the typical EV batteries voltage range is presented in this article. The proposed configuration is based on modular three-phase interleaved converters and supplied by the low-voltage ac grid. The ac/dc interleaved three-phase active rectifier is composed of three standard two-level three-phase converter modules with a possibility to slightly adjust the dc-link voltage level in order to null the output current ripple. A modular interleaved dc/dc converter, formed by the same three-phase converter modules connected in parallel, is used as an interface between the dc link and the battery. The use of low-cost, standard and industry-recognized three-phase power modules for high-power fast EV charging stations enables the reduction of capital and maintenance costs of the charging facilities. The effect of coupling on the individual input/output inductors and total input/output current ripples has been investigated as well, considering both possible coupling implementations, i.e., inverse and direct coupling. Numerical simulations are reported to confirm the feasibility and the effectiveness of the whole EV fast charging configuration, including the proposed control strategy aimed to null the ripple of the output current. Experimental results are provided by a reduced scale prototype of the output stage to verify the ripple-free output current operation capability.
COBISS.SI-ID: 12615764
The aim of this paper is to present a new analytical model developed for open-circuit magnetic field calculation in U-shape interior permanent magnet (IPM) machine. The model is developed based on the 2-D subdomain-model approach by solving Poisson’s and Laplace’s equations. The comprehensive theoretical derivations of the final analytical equations for the magnetic flux density distribution in the air-gap and in the permanent magnets are explained in detail. We also provide the calculation algorithm in form of a flow diagram suitable for engineers to compute the radial and the tangential component of the magnetic flux density in all subdomains of slotless brushless machines with any possible number of rotor pole pairs of U-shaped IPMs. A slightly modified algorithm also applies to V-shaped IPMs.
COBISS.SI-ID: 12682068
The book encompasses actual state of the art and authors’ contribution to the field of electrical drives. It covers the area of basic mechanical equations, general vector theory and description of operation and control of drives with DC, induction and synchronous drives, with additional description of control approaches and their implementation to microcomputers. In the second part, elements and operation of converter circuits, together with sensors of physical quantities, required for proper operation of the drive, are described.
COBISS.SI-ID: 12490580
This study presents a model-based method for detecting an open-circuit fault in battery supply unit feeding a permanent magnet synchronous motor. Apart from the commonly present DC voltage sensor at converter's input, no additional sensors are required. As a first step, the DC supply system is modelled as a lumped parameter electric circuit. Further, a procedure for estimation of DC supply voltage based on inverter's current and open-circuit battery voltage is proposed. A sliding mode observer is then used to obtain the actual value of open-circuit battery voltage, required by the modelling algorithm. Consequently, an open-circuit fault in a DC supply circuitry is determined based on the analysis of discrepancy between the estimated and measured DC supply voltage. Detection algorithm has been tested on a laboratory setup and its functionality is confirmed by experimental results.
COBISS.SI-ID: 12233044
Despite its rich hydropower potential, Slovenia is having difficulty fulfilling its obligations concerning the utilization of renewable energy sources. This situation could be improved partly by the positive effects of economic growth and by a turnaround in the construction of small power plants after re-establishing the support scheme. The sites of abandoned water mills usually offer non-negligible hydropower potential with ultra-low head, efficiently exploitable by an Archimedes screw. For assessment of electrical energy production, hydrological data are taken into account in combination with closely examined conditions that can be expected from water streams with ultra-low head, located in a region with relatively abundant precipitation. Several simulation models were developed for constant speed and variable speed small hydropower plant (SHP) installations, exploiting a combination of manufacturer’s data-based equipment models, in-situ measurements and published data. Surprisingly, the variable speed operated SHP produces less than the constant speed operated SHP. The seasonal limitation of hydropower potential exploitation, which is defined in order to minimize the influence of SHP operation on flora and fauna in the river, as well as the technical limitations for operating an Archimedes screw given by its manufacturer, have only moderate or no effect on production.
COBISS.SI-ID: 12194644