Supercharging system, power supply device for supercharging system, power supply control method for supercharging system, and engine system

A power supply control method for a supercharging system that includes:

• a first compressor disposed in an intake air flow passage in which intake air supplied to an engine is circulated and configured to compress the intake air by being driven;
• an electric motor that is configured to drive the first compressor;
• a second compressor disposed in the intake air flow passage independently from the first compressor and configured to compress the intake air;
• a turbine disposed in an exhaust gas flow passage in which exhaust gas from the engine is circulated and configured to drive the second compressor by being rotated by the exhaust gas;
• a first power supply circuit including a power storage device having a first capacity and configured to supply electricity of a first voltage to the electric motor;
• and
• a second power supply circuit including a power storage device having a second capacity smaller than the first capacity and configured to supply electricity of a second voltage higher than the first voltage to the electric motor,
• the power supply control method comprising:
• supplying electricity from the second power supply circuit to the electric motor when an operation of the electric motor starts;
• and
• supplying electricity from the first power supply circuit to the electric motor after the supplying of electricity from the second power supply circuit to the electric motor.