Conversion device

A conversion device used in a power supply system including:

• a power supply device in which a first battery unit and a second battery unit are switched between a series connection and a parallel connection;
• a plurality of first conversion circuits that each convert DC power input to DC ends thereof to AC power and output the AC power to AC ends thereof;
• a plurality of transformers in each of which a first coil that is connected to the AC ends of a corresponding one of the plurality of first conversion circuits is magnetically coupled to a plurality of second coils;
• and
• a plurality of capacitors that are each connected to the DC ends of a corresponding one of the plurality of first conversion circuits,
• the conversion device comprising:
• the plurality of first conversion circuits;
• the plurality of transformers that are connected to the plurality of first conversion circuits in one-to-one correspondence;
• a plurality of second conversion circuits;
• and
• a plurality of third conversion circuits,
• wherein one of the plurality of second conversion circuits performs a first operation and a second operation, the first operation being an operation of converting AC power generated at one of the plurality of second coils of one of the plurality of transformers to DC power and outputting the DC power to the first battery unit, and the second operation being an operation of converting DC power input from the first battery unit to generate AC power at the one of the plurality of second coils of the one of the plurality of transformers,
• another one of the plurality of second conversion circuits performs a third operation and a fourth operation, the third operation being an operation of converting AC power generated at one of the plurality of second coils of another one of the plurality of transformers to DC power and outputting the DC power to the second battery unit, and the fourth operation being an operation of converting DC power input from the second battery unit to generate AC power at the one of the plurality of second coils of the other one of the plurality of transformers,
• one of the plurality of third conversion circuits performs a fifth operation of converting AC power input to another one of the plurality of second coils of the one of the plurality of transformers to DC power and outputting the DC power to a common path, and
• another one of the plurality of third conversion circuits performs a sixth operation of converting AC power input to another one of the plurality of second coils of the other one of the plurality of transformers to DC power and outputting the DC power to the common path.