  AC transmission lines with lengths greater than 80km cannot be used to their
maximum capacity due to limits in voltage drops and transient stability. This
inefficient way of using conductors in a transmission line can be overcome if
the electrical frequency at which energy is transmitted is reduced. This is why
this work focuses on the comparison of the Modular Multilevel Matrix Converter
(MMMC) and the Back-to-Back Modular Multilevel Converter (BTB-MMC), topologies
that have shown qualities as frequency converters. For comparison, an
analytical model of each topology is used to relate design considerations to
their operational variables. Among the aspects to be compared are, the
requirements of the semiconductors, the required reactive components, operating
losses and fault tolerance. Detailed design equations, EMTP simulations, and
comparison table are presented.
