A New Approach for Power Losses Evaluation of IGBT/Diode Module

Electric power systems are facing tremendous changes and power electronic devices are playing an increasingly crucial role in this transformation. In this contest, the study of power electronic devices behavior becomes of the utmost importance, and in particular, evaluation of their losses to understand their performance. Several methods can be found in literature to evaluate power or energy losses, but each of them is associated with shortcomings (such as missing an important factor or having narrow current or voltage range) that in practice become a strong limit to implement them or in a simulation process. To overcome this problem, this paper evaluates existing methods and proposes new loss calculation methods for power electronics losses that can be used within simulation tools at any converter configuration and application range, splitting power electronic losses into switching and conduction losses. The proposed new approach formulates each loss calculation procedure in a systematic way. The presented methods are implemented in Matlab Simulink and simulation results are compared with data obtained from the Semikron SemiSel v4 online tool, which is used as a benchmark. The outcomes reveal that, with this new approach, the proposed methods can cover wider working operation range compared to the existing methods having better accuracy.

Dynamics of hindered CF3-rotor in 2,5-bis (trifl uoromethyl )-nitroben zene radical -anion in anhydro us DMF. A temperature - activation theory of reversible HFS transformations of EPR spectrum

The temperature dependence of EPR spectrum of 2,5-bis(trifluoromethyl)nitrobenzene radical anion in anhydrous DMF was investigated. Internal dynamics of hindered rotation of the CF3-group in ortho-position to NO2-group causes HFS modulation. The spectrum changes are reversible and temperature-dependent. An original temperature-activation representation of complex spectral density was proposed instead of the traditional spectral-kinetics representation to explain the observed transformation. The change resulted in a new convenient phenomenological reconstruction model, which allowed simulating the spectra in the whole temperature range. Splitting constants and contributions to the spectral widths of the spectral lines were found. The activation energy of the CF3-group hindered rotation is significant and amounts to 37 kJ/mol.