Marek Galek

Modular DC/DC converter with improved efficiency for electric vehicles applications

A modular approach for DC/DC converters to obtain desired voltages and currents is presented in this paper. A high efficiency low switch count isolated push-pull DC/DC converter is used as a unit module. The converters are connected in input series or parallel and output series, or parallel configuration to meet the desired power level. The aim is to obtain a flexible DC/DC converter block which can be used to cover a wide power range as well as a wide input and output voltage range. The converters and the communication topologies are designed in such a way that the numbers of unit modules can be connected in several different configurations to achieve the desired requirements with a minimum effort. The experimental details of a configuration with two converters, and with four converters, are considered in this work.

Frequency domain prediction of conducted EMI in power converters with front-end three-phase diode-bridge

This paper investigates the frequency domain prediction of conducted EMI within power converters supplied by front-end three-phase diode-bridge. Noise source, noise propagation path and noise receiver are identified. Difficulty due to the presence of diode-bridge is analyzed and a method is proposed and verified by measurement to take the variation of propagation path into account while still enable the simulation to be carried out in frequency domain.

Experimental characterization of conducted EMI in three-phase power electronics system using terminal model

This paper investigates the relevant issues for experimental characterization of conducted EMI resulting from three-phase power electronics system. Terminal model is used to describe the EMI behavior. The theoretical analysis and equivalent terminal model for three-phase power electronics system are conducted and proposed respectively. The measurement setup which fulfills the requirement of parameter extraction is then discussed. Measurement procedure is described and the obtained data is processed to calculate the desired parameters. Using the model and parameters from experimental extraction, conducted EMI level can be predicted and the results are compared with measurement to validate the correctness of the characterization.

Terminal characterization of conducted EMI in three-phase power converters

Terminal characterization of conducted EMI in power converters helps to estimate the effect of inserting EMI filter or changing connection conditions and thus alleviates the effort of designing suitable EMI attenuation measures. In this paper, a procedure to characterize the conducted EMI in three-phase power converters with terminal model is proposed. The model consists of active sources and passive admittance matrix. Parameters inside model are calculated with terminal currents and voltages at LISN, by considering overall setup as series cascaded transfer matrix. The modeling is based on either time-domain simulations or experimental data acquisition. The effectiveness of model is verified by comparing predicted and simulated as well as measured results at changing connection conditions.

S-parameters characterization and sequence model of three-phase EMI filter

This paper investigates the characterization of three-phase EMI filter using S-parameters and the use of sequence model to fully describe the high frequency behavior. Characterization of three-phase EMI filter helps to understand the influence of real filter on overall EMI performance and provides information for filter selection or design. The characterization is divided into two types: component level or system level, which can be chosen to use according to design conditions. S-parameters are chosen as network parameters to characterize because of the convenience to measure them in high frequency range. Beside circuitry model of filter, sequence model of filter is proposed to better describe the attenuation and conversion between different forms of noise, which improves the understanding towards filter behavior compared to traditional separation of common and differential mode noise. Corresponding equations are provided to obtain parameters in the sequence model. At the end, the predictions of insertion loss and energy transfer ratio which represent the grade of mode conversion based on sequence model are shown and compared with results from conventional measurement method.