Date of Award:


Document Type:


Degree Name:

Master of Science (MS)


Electrical and Computer Engineering

Committee Chair(s)

Regan A. Zane


Regan A. Zane


Hongjie Wang


Greg N. Droge


This thesis presents the analysis and design of high-efficiency battery chargers for heavy duty EV applications. The rise in popularity of the electric vehicles (EVs) due to their increased efficiency over conventional internal combustion engines, has driven the need for more battery charging infrastructure. Furthermore, heavy duty vehicles are also being converted to electric to fill needs such as public transportation via bus fleets as well as cargo delivery via semi-trucks. Such heavy duty vehicles require more energy than personal transportation vehicles and thus require larger battery packs. To charge heavy duty battery packs in the same amount of time as the typical EV, higher power chargers are required.

Energy is distributed through the grid network, and a battery charger is converts the grid power into a regulated output for battery charging. The novel battery charging designs investigated in this thesis are classified differently than traditional designs because they have fewer switching stages to convert the power. The unique approach taken allows these designs to have higher efficiency overall than a traditional battery charger design. The new converter designs are refereed to as the three-level (3L) asymmetrical full bridge (3LAFB)and 3L asymmetrical dual active bridge (3LADAB). The operation of each converter is briefly discussed to help develop context for the hardware and controller designs. The controller design for the 3LAFB topology is developed to explain the control objectives of the 3-port dc-dc converter. Hardware results prototype designs are presented to validate proposed chargers and controller designs. A high power extreme fast charger (XFC) structure is proposed using multiple lower power modules. The high-efficiency design of a single module is presented and hardware results are given.