Patent ID: 8310083

Claim:
An apparatus comprising: a DC-link; a load coupled to the DC-link; and an energy conversion system comprising: a first energy storage device; a first voltage converter coupled to the first energy storage device and to the DC-link, the first voltage converter configured to: convert a first DC voltage from the first energy storage device into a second DC voltage based on a command signal and based on a first adjustment signal; and supply the second DC voltage to the DC-link; a first bus voltage controller coupled to the DC-link and to the first voltage converter, the first bus voltage controller configured to: iterate calculation of the first adjustment signal based on the command signal and based on a measured voltage of the DC-link; and communicate each iterated calculation of the first adjustment signal to the first voltage converter; a supervisory controller coupled to the first voltage converter and to the first bus voltage controller, the supervisory controller configured to: iterate calculation of the command signal based on the load and based on a desired DC-link voltage for the load; and communicate each iterated calculation of the command signal to the first voltage converter and to the first bus voltage controller; and wherein a frequency of the first bus voltage controller to communicate each iterated calculation of the first adjustment signal is higher than a frequency of the supervisory controller to communicate each iterated calculation of the command signal.