Bi-directional battery voltage converter

A vehicle electrical system for supplying electrical power to an electrical load, the system comprising:

• a system bus,
• a first battery;
• a first bi-directional battery voltage converter controllably transferring a first current between the first battery and the system bus;
• a second battery;
• a second bi-directional battery voltage converter controllably transferring a second current between the second battery and the system bus;
• and
• a controller for controlling the first bi-directional battery voltage converter and the second bi-directional battery voltage converter such that the first current and the second current are equal portions of a load current supplied to an electrical load connected to the system bus, wherein the first bi-directional battery voltage converter includes an inductor, a first switch selectively connecting the inductor to the first battery, a second switch selectively connecting the inductor to the first battery, a third switch selectively connecting the inductor to the system bus, a fourth switch selectively connecting the inductor to the system bus, and a routing circuit, controlled by the controller, opening and closing the first, second, third, and fourth switches in pairs to charge the inductor from one of the vehicle electrical system and the battery and to discharge the inductor to the other of the vehicle electrical system and the first battery.

A bi-directional battery voltage converter for use with a vehicle electrical system, comprising:

• an inductor;
• a first switch selectively coupling the inductor to a first battery;
• a second switch selectively coupling the inductor to the first battery;
• a third switch selectively coupling the inductor to the vehicle electrical system;
• a fourth switch selectively coupling the inductor to the vehicle electrical system;
• a routing circuit connected to each of the first, second, third, and fourth switches, the routing circuit controllably opening and closing the switches in pairs such that the inductor is charged from one of the vehicle electrical system and the battery and discharged to the other of the vehicle electrical system and the battery;
• and
• a controller controlling the routing circuit to deliver a portion of a load current supplied to a connected electrical load, the portion based upon the availability of other current sources.