Abstract—This paper explores the limits of neutral-point current
control in back-to-back connected three-level converters. The
theoretical analysis used is based on a mathematical neutral-point
current model, which can be extended to apply to converters with
higher numbers of levels. The low-frequency ripple, which appears
in the neutral-point voltage for some operation conditions, can be
removed for an extended operating area when two converters are
connected back to back to the same dc bus. As a consequence, a
lower voltage is applied to the devices, and the value of the capacitors
can also be significantly reduced. Some practical graphics are
given to represent the design according to the specifications of the
application.