Compact and efficient power electronics with applications to solar PV, automotive, and aerospace systems

Improving the power density of a power converter has many benefits for systems integration. Aspects such as thermal management, weight, conformation to mounting locations, and the footprint of the converter all become critical factors as systems continue to scale down in size. The flying-capacitor multilevel (FCML) converter topology is of interest because it has characteristics which contribute to high power density. This work presents some different applications of the FCML converter which exhibit characteristics of high power density. One such application is a converter built on a flexible polyimide substrate circuit board controlled to achieve quasi-square-wave (QSW) zero-voltage switching (ZVS). ZVS minimizes switching losses and enables high-frequency operation of the converter. The flexible nature of the board enables the converter to be integrated to non-flat surfaces such as motors, pipes, or airfoils. Another such application is the minimization of size and weight of the power stage of a maximum power point tracking system for usage in the solar photovoltaic space. The frequency multiplication effect of the FCML topology enables a 4x reduction in size of this power stage. Both such applications are made possible with the usage of high device switching frequency, fast GaN transistors, and careful thermal management