Systems and methods for integrated high voltage and low voltage converter for bidirectional onboard battery charger

A system comprising:

• a DC to DC converter (DC-DC converter) including:
• a high voltage buck-boost converter having a secondary side connectable to a high voltage battery, the high voltage buck-boost converter including a first high voltage switch and a second high voltage switch, wherein the high voltage buck-boost converter is configured to operate in one or more modes, including at least one mode of the one or more modes where the first high voltage switch is configured to be in an open/closed state that is different from an open/closed state of the second high voltage switch;
• a low voltage buck-boost converter having a secondary side connectable to a low voltage battery, the low voltage buck-boost converter including a first low voltage switch and a second low voltage switch, wherein the low voltage buck-boost converter is configured to operate in one or more modes, including at least one mode of the one or more modes where the first low voltage switch is configured to be in an open/closed state that is different from an open/closed state of the second low voltage switch;
• and
• one or more transformers having a primary side connectable to an AC-DC converter, a secondary side connected to a primary side of the high voltage buck-boost converter, and a tertiary side connected to a primary side of the low voltage buck-boost converter;
• and
• one or more controllers configured to control an operation of the high voltage buck-boost converter and the low voltage buck-boost converter to control a power transfer between two or more of a line voltage, the high voltage battery, or the low voltage battery;
• wherein the one or more controllers control an operation of the first high voltage switch, the second high voltage switch, the first low voltage switch, and the second low voltage switch to configure the DC-DC converter into each of (i) a charging mode with both an HV and LV buck operation, (ii) a charging mode with an LV only buck operation, wherein the first high voltage switch is in the closed state and the second high voltage switch is in the open state, (iii) an HV to LV conversion mode with HV and LV buck operation, (iv) an HV to LV conversion mode with HV only buck operation, wherein the first low voltage switch is in the closed state and the second low voltage switch is in the open state, and (v) an HV to LV conversion mode with no HV or LV buck operation, wherein the first high voltage switch is in the closed state, the second high voltage switch is in the open state, the first low voltage switch is in the closed state, and the second low voltage switch is in the open state.

A method for controlling a system including a DC-DC converter including one or more transformers, a high voltage buck-boost converter including a first high voltage switch and a second high voltage switch, and a low voltage buck-boost converter including a first low voltage switch and a second low voltage switch, the method comprising performing, by one or more controllers, operations including:

• controlling an operation of the high voltage buck-boost converter and the low voltage buck-boost converter to control a power transfer through the one or more transformers and one or more of the high voltage buck-boost converter or the low voltage buck-boost converter,
• wherein the operations further include:
• controlling the high voltage buck-boost converter to operate in one or more modes, including at least one mode of the one or more modes where the first high voltage switch is configured to be in an open/closed state that is different from an open/closed state of the second high voltage switch,
• controlling the low voltage buck-boost converter to operate in one or more modes, including at least one mode of the one or more modes where the first low voltage switch is configured to be in an open/closed state that is different from an open/closed state of the second low voltage switch, and
• controlling an operation of one or more switches of the DC-DC converter to configure the DC-DC converter into each of (i) a charging mode with both an HV and LV buck operation, (ii) a charging mode with an LV only buck operation, wherein the first high voltage switch is in the closed state and the second high voltage switch is in the open state, (iii) an HV to LV conversion mode with HV and LV buck operation, (iv) an HV to LV conversion mode with HV only buck operation, wherein the first low voltage switch is in the closed state and the second low voltage switch is in the open state, and (v) an HV to LV conversion mode with no HV or LV buck operation.