Compressor unit and gas supply apparatus

A compressor unit comprising:

• a compressor configured to compress a gas and store the compressed gas in a pressure accumulator;
• an electric motor driving the compressor, the electric motor being a constant torque motor providing a constant rated output torque in a standard rotation region of the electric motor, the standard rotation region being a rotation region at or below a standard speed;
• and
• a controller for controlling the electric motor, the controller including:
• means for maintaining a rated torque of the electric motor against a change of a rotational speed in the standard rotation region,
• means for decreasing an output torque of the electric motor from the rated torque as the rotational speed of the electric motor increases in an overspeed region, the overspeed region being a rotation region having the rotational speed above the standard speed, and
• means for driving the electric motor in the overspeed region based on an overspeed operation control of the controller when a pressure of the compressed gas in the pressure accumulator is less than a predetermined pressure.