Reduction of common mode currents generated by three-level inverters

[joannapaul]

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Abstract
In adjustable speed drive applications, the switching of the inverter semiconductors generates common
mode currents as well as harmful overvoltages on the motor terminals when long cables are used.
Consequently, bulky and expensive input and output filters must be used. This work aims at reducing
these disturbances from their origin by using a three-level neutral-point-clamped (NPC) inverter
controlled with a new pulse-width-modulation (PWM) strategy. Whereas previous common mode
noise-reducing strategies usually generate higher overvoltages than conventional ones, the proposed
PWM is able to manage both problems thanks to its internal degrees of freedom