Comparison of hybrid propulsion drive schemes

This paper provides a brief overview of a hybrid drives which have become popular in recent years. These drives combine two or more multilevel power inverters to obtain exceptional power quality which is necessary for Naval propulsion applications. Furthermore, for ship propulsion, where it may be difficult to obtain several isolated dc voltage sources, the inverter control can be set so that only one real dc power source is needed (or one per phase in the case of a series H-bridge type). Three types of hybrid drives considered and their advantages and limitations are described. Commonalities of the control of each hybrid drive type is discussed and three control schemes are applied to the various topologies in a set of simulation examples.