Active Thermal Control in Neutral-Point-Clamped Multilevel Converters
based on Switching-Cell Arrays
Abstract
Neutral-Point-Clamped multilevel converters are nowadays a suitable
solution to implement low-medium voltage and power applications, thanks
to their intrinsic superior voltage and current quality. The
conventional configurations of these converters present uneven power
loss distribution, causing thermal stress in some power semiconductors,
which weakens the power converter reliability. For overcoming it, an
implementation of the Neutral-Point-Clamped multilevel converter based
on a Switching-Cell Array is introduced, adding redundant conduction
paths on one side and more options to distribute the switching losses on
the other side. An active thermal control is proposed here to balance
the temperature distribution in the converter. A four-level converter
has been implemented to evaluate the proposed solution. Experimental
results show that the proposed implementation and active thermal control
present enhanced temperature distribution in the converter and therefore
reduced thermal stress and better reliability.