Abstract: A method for characterizing electrical impedance of an energy storage device includes the following steps: (a) controlling a first switching power converter to transfer electric power between a first energy storage device and a load, (b) controlling the first switching power converter to generate a sinusoidal perturbation on electric current flowing through the first energy storage device, (c) determining an alternating current (AC) component of the electric current flowing through the first energy storage device, (d) determining an AC component of voltage across the first energy storage device, and (e) determining a complex impedance of the first energy storage device based at least in part on the AC component of the electric current flowing through the first energy storage device and the AC component of the voltage across the first energy storage device.

Abstract: A method for characterizing electrical impedance of an energy storage device includes the following steps: (a) controlling a first switching power converter to transfer electric power between a first energy storage device and a load, (b) controlling the first switching power converter to generate a sinusoidal perturbation on electric current flowing through the first energy storage device, (c) determining an alternating current (AC) component of the electric current flowing through the first energy storage device, (d) determining an AC component of voltage across the first energy storage device, and (e) determining a complex impedance of the first energy storage device based at least in part on the AC component of the electric current flowing through the first energy storage device and the AC component of the voltage across the first energy storage device.

Abstract: A modular battery array includes a plurality of battery modules electrically coupled in series to a high-voltage electric power bus, a low-voltage electric power bus, and a respective switching power converter electrically interfacing each of the plurality of battery modules with the low-voltage electric power bus. Each of the plurality of battery modules includes a plurality of battery cells electrically coupled in series and at least one switching power converter for balancing energy stored in the plurality of battery cells of the battery module.