Study of the multilevel converters in DC-DC applications

Multilevel converters have been demonstrated to have many advantages such as low harmonic, low voltage stress, and high power capability. However, most of the researches are focused on high power AC-DC and DC-AC applications. This paper presents several multilevel DC-DC converters, which can be used in automotive applications as well as in high power applications. Based on the diode-clamp, flying-capacitor, and cascaded multilevel inverters, their correlative DC-DC converters are derived. A 1 kW prototype of four-level flying-capacitor DC-DC converter used in automotive systems was built as an example to demonstrate the advantages.