Contents I. Introduction
Multilevel converter topologies have attracted much research interest since the 1980s, from the conventional neutral point clamped (NPC) converters, flying capacitor (FC) converters, to cascaded H-bridge converters [1]. Based on the fundamental topology structures are mentioned above, an unremitting and persistent research for developing advanced multilevel converter topologies with improved characteristics in which the cascaded H-bridge (CHB) converter has become a research focus since it was first presented in 1988 [2]–[4]. Distinguished features of CHB converter, including modularity and, promotes the utilization of CHB topology in high voltage and high power applications. Therefore, it is desirable to seek new applications for CHB converter. Work [5] presents a switch mode multilevel power amplifier (PA) system for driving underwater electro-acoustic transducer, which is appealing for the industrial and military applications in recent years. In military equipment application, submarine electro-acoustic transduction system, as shown in Fig. 1, PA consists of DC/DC and DC/AC, providing stable high power electrical energy for the transducer, is eager for the topology with the features, including high fidelity, high efficiency, excellent dynamic response, and high power density.
