Fundamentals of a new diode clamping multilevel inverter

The conventional diode clamping inverter suffers from such problems as DC link unbalance, indirect clamping of the inner devices, turn-on snubbing of the inner DC rails as well as series association of the clamping diodes etc. It is due largely to these problems that the application of the conventional diode clamping inverter in practice has been deterred, in spite of the growing discussion in the literature. The paper proposes a new diode clamping inverter, which works without the series association of the clamping diodes. An auxiliary resistive clamping network solving the indirect clamping problem of the inner devices is also discussed for both the new and conventional diode clamping inverter. Operation principle, clamping mechanism, auxiliary clamping as well as experimentation are presented.