Power supply system

A power supply system comprising:

• a first battery;
• a second battery;
• a voltage converter including a plurality of switching elements, the switching elements being configured to bidirectionally convert voltage between one or both of the first battery and the second battery and an output power line and switch connection of the first battery and the second battery to the output power line between series connection and parallel connection;
• and
• a controller configured to turn on or off the plurality of switching elements in accordance with pulse width modulation control, wherein
• the output power line includes a first power line and a second power line lower in potential than the first power line,
• the plurality of switching elements include first, second, third and fourth switching elements provided in series with each other in order from the first power line toward the second power line,
• the first battery is connected in parallel with the third and fourth switching elements, the second battery is connected in parallel with the second and third switching elements, and
• the controller is configured to, when a total high-level period that is a total period of a first high-level period and a second high-level period is shorter than a duty cycle period, execute phase control by mixing first control with second control, the first high-level period being a high-level period of a first pulse width modulation control signal for controlling first voltage conversion of a first voltage conversion circuit established between the first battery and the output power line, the second high-level period being a high-level period of a second pulse width modulation control signal for controlling second voltage conversion of a second voltage conversion circuit established between the second battery and the output power line, the duty cycle period being a total period of each of low-level periods of pulse width modulation control signals and a corresponding one of the high-level periods of the pulse width modulation control signals, the first control being control in which phases of the pulse width modulation control signals are controlled such that the first high-level period of the first pulse width modulation control signal and the second high-level period of the second pulse width modulation control signal overlap with each other, the second control being control in which the phases of the pulse width modulation control signals are controlled such that the first high-level period of the first pulse width modulation control signal and the second high-level period of the second pulse width modulation control signal do not overlap with each other.

A power supply system comprising:

• a first battery;
• a second battery;
• a voltage converter including a plurality of switching elements, the switching elements being configured to bidirectionally convert voltage between one or both of the first battery and the second battery and an output power line and switch connection of the first battery and the second battery to the output power line between series connection and parallel connection;
• and
• a controller configured to turn on or off the plurality of switching elements in accordance with pulse width modulation control, wherein
• the output power line includes a first power line and a second power line lower in potential than the first power line,
• the plurality of switching elements include first, second, third and fourth switching elements provided in series with each other in order from the first power line toward the second power line,
• the first battery is connected in parallel with the third and fourth switching elements,
• the second battery is connected in parallel with the second and third switching elements, and
• the controller is configured to, during a period in which a first pulse width modulation control signal for controlling first voltage conversion of a first voltage conversion circuit established between the first battery and the output power line is at a low level, change a second pulse width modulation control signal for controlling second voltage conversion of a second voltage conversion circuit established between the second battery and the output power line from a low level to a high level and then return to the low level.