Driving device, air conditioner, and method for controlling compressor

An air conditioner comprising:

• a compressor including a shaft, a motor including coils, a compression mechanism including a rotary piston to rotate together with the shaft and driven by the motor, a shell covering the motor and the compression mechanism, and a discharge pipe;
• an inverter connected to the coils;
• a connection switching device to switch a connection state of the coils between a first connection state and a second connection state;
• a controller to control the inverter and the connection switching device;
• and
• a compressor state detector to detect a state of the compressor, wherein
• when the connection state of the coils is the first connection state, the controller controls rotation speed of the motor based on a first detection value detected by the compressor state detector and a first temperature,
• when the connection state of the coils is the second connection state, the controller controls the rotation speed of the motor based on a second detection value detected by the compressor state detector and a second temperature, and
• wherein the state of the compressor is a temperature of at least one of the shell, the discharge pipe, or a refrigerant in the compressor,
• the first temperature and the second temperature are set depending on the connection state of the coils, and
• the second temperature is set to be larger than the first temperature when the first connection state is Y connection and the second connection state is delta connection.

A method for controlling a compressor including a motor in which a connection state of coils can be switched between a first connection state and a second connection state, the method comprising:

• detecting a state of the compressor as a first detection value when the connection state of the coils is the first connection state;
• controlling rotation speed of the motor based on the first detection value and a first temperature when the connection state of the coils is the first connection state;
• detecting the state of the compressor as a second detection value when the connection state of the coils is the second connection state;
• and
• controlling the rotation speed of the motor based on the second detection value and a second temperature when the connection state of the coils is the second connection state, and
• wherein the state of the compressor is a temperature of at least one of the shell, a discharge pipe of the compressor, or a refrigerant in the compressor,
• the first temperature and the second temperature are set depending on the connection state of the coils, and
• the second temperature is set to be larger than the first temperature when the first connection state is Y connection and the second connection state is delta connection.