System and method for a DC/DC converter

A method for operating an electronic drive circuit, comprising:

• coupling an energy storage device to a first bridge circuit, the first bridge circuit comprising at least one leg having two switching devices;
• coupling a first winding of a transformer to the first bridge circuit;
• coupling a second winding of the transformer to the energy storage device through a center tap;
• coupling a second bridge circuit to the second winding of the transformer, the second bridge circuit comprising at least one pair of switching devices connected in series, the pair of switching devices operable to allow current to flow in both directions;
• coupling a DC bus to the second bridge circuit;
• and
• configuring a controller to operate the switching devices to:
• buck a DC voltage from the energy storage device to supply to the DC bus in a first mode of operation;
• boost a DC voltage output from the energy storage device to supply to the DC bus in a second mode of operation, wherein the controller is configured to operate the first bridge circuit as a pulse width modulated, variable frequency, or phase shift converter and the second bridge circuit as a rectifier during the first and second modes of operation;
• buck a DC voltage from the DC bus to supply to the energy storage device in a third mode of operation;
• and
• boost a DC voltage output from the DC bus to supply to the energy storage device in a fourth mode of operation, wherein the controller is configured to operate the first bridge circuit as a rectifier and the second bridge circuit as a pulse width modulated converter during the third and fourth modes of operation.

An electric vehicle comprising:

• an energy storage device;
• a DC/DC converter comprising:
• a first bridge circuit coupled to the energy storage device, the first bridge circuit comprising at least one leg having two switching devices;
• a resonant circuit coupled to the first bridge circuit;
• a transformer comprising:
• a first winding coupled to the resonant circuit;
• and
• a second winding coupled to the energy storage device through a center tap;
• and
• a second bridge circuit coupled to the second winding of the transformer, the second bridge circuit comprising at least one pair of switching devices connected in series, the pair of switching devices operable to allow current to flow in both directions;
• a traction drive system coupled to the second bridge circuit, the traction drive system comprising an inverter and traction motor;
• and
• a controller configured to operate the DC/DC converter to:
• buck a DC voltage from the energy storage device to supply to the traction drive system in a first mode of operation;
• boost a DC voltage from the energy storage device to supply to the traction drive system in a second mode of operation, wherein the controller is configured to operate the first bridge circuit as a pulse width modulated, variable frequency, or phase shift converter and the second bridge circuit as a rectifier during the first and second modes of operation;
• buck a DC voltage from the traction drive system to supply to the energy storage device in a third mode of operation;
• and
• boost a DC voltage from the traction drive system to supply to the energy storage device in a fourth mode of operation, wherein the controller is configured to operate the first bridge circuit as a full wave diode rectifier and the second bridge circuit as a pulse width modulated converter during the third and fourth modes of operation.