ELECTRICAL POWER SYSTEM WITH MULTIPLE ENERGY STORAGE MODULES

An example electrical power system includes a DC bus including a positive rail configured to provide a positive DC voltage, a negative rail configured to provide a negative DC voltage, and a ground rail. A first ESM and a second ESM are connected to the DC bus. Each ESM includes an energy storage device. The first and second ESM are connected to and configured to provide an output voltage to a respective one of the positive and negative rail. A node connects the first and second ESMs to each other and to the ground rail. A controller is configured to determine values for the output voltages for use during at least one of a discharging mode and a charging mode bus based on a difference between a state of charge value of the first and second energy storage devices. A method of operating an electrical power system is also disclosed.