Direct current control of multilevel drive with novel floating capacitor control

This paper proposes a modular control strategy which can be applied to cascaded multilevel power converters. Modulation strategies can take advantage of the modularity of these power converter topologies proposing modular and general control strategies. This paper proposes a control algorithm able to obtain a one-to one correspondence between the switching elements and the control variables, through the introduction of auxiliary control signals. Moreover this approach makes it possible to increase control system degrees of freedom which can be used to realize other control targets as the control of voltage balance between the dc links of the cascaded power converter, as discussed in the paper. Simulation tests validate the proposed control strategy.