Highly Compact Charging With Power-Factor Correction for Electric Vehicles Through Functional Integration Into a Dynamically Reconfigurable Battery

Dynamically reconfigurable batteries in electric vehicles can improve overall battery as well as system performance. Furthermore, they can functionally integrate a variety of functions that previously required separate electronics to save space, mass, and cost. This paper demonstrates that a dynamically reconfigurable battery can operate as its own charger, connecting to the grid directly through a rectifier-filter combination without the need for any additional active converter stages. A cascaded half-bridge reconfigurable battery in combination with a simple, highly cost- and space-efficient diode bridge as a grid interface can form a highly-compact high-power on-board ac charger. In this configuration, the battery can exploit its capability of multilevel output for small filter size already at almost negligibly small switching frequencies for field-effect transistors. Proper control can perform grid-side power-factor correction concurrently with module charging and module balancing as three concurrent objectives. Experimental results confirm the ability of the control system to regulate the power factor, the power flow for module balancing, and battery charging.