| Abstract |
This paper deals with the rating of suitable low-pass filters to be used together with Medium
Voltage NPC IGBT inverters in certain voltage distortion sensitive applications. It will provide
the rating criteria of such line side and motor side filters. In these two cases different is the goal
to reach and different are the proposed solutions.
The authors start from the analysis of output voltage spectrum of NPC inverters that implement a
given modulation strategy [1] and describe all steps necessary to define a suitable rating of filter
components. The inverter output voltage spectrum is clearly the basis to define the filter
characteristics. The paper shows, besides, as also other factors influence the characteristics of the
inverter-filter system. In fact, in particular for high power drives, where the size of filter
components is large, the Q-factor results to be, with good reason, comparatively high, and the Qfactor
has a direct influence on the damping coefficient of the system. Other conditions that
impact on the filter rating can be related to the control algorithms used for the application.
Finally, the paper shows how the goals were met by records taken from tests done on a 6MVA
NPC IGBT inverter. |
