Patent ID: 11863099
Assignee: MITSUBISHI ELECTRIC CORPORATION
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  F | IPC F  H

Claim 15:
16. An air conditioner using a refrigeration cycle, the air conditioner comprising:
a compressor to compress a refrigerant used in the refrigeration cycle;
a fan to blow air to a heat exchanger;
a converter to generate a DC voltage;
an inverter to generate three-phase AC voltages from the DC voltage;
a motor to produce a driving force for driving the compressor with a plurality of coils, the three-phase AC voltages being applied to the coils;
a connection switching unit to switch connection states of the coils between a first connection state and a second connection state;
a current detection circuit to detect a current value of a current on an input side of the inverter, and
a controller to detect an abnormality of the connection switching unit,
wherein the abnormality is opening failure or short-circuit failure,
wherein the controller detects the abnormality of the connection switching unit, based on the current value,
wherein the connection switching unit sets the connection states of the coils to one of the first connection state and the second connection state,
the inverter is connected to the motor with a first line, a second line, and a third line,
the inverter applies a voltage so that a current flows in order in only a first direction from the first line and the second line to the third line, in only a second direction from the second line and the third line to the first line, and in only a third direction from the first line and the third line to the second line, individually,
the current detection circuit
detects, as a first current value, a current value of the current on the input side of the inverter when the inverter applies the voltage so that the current flows in only the first direction,
detects, as a second current value, a current value of the current on the input side of the inverter when the inverter applies the voltage so that the current flows in only the second direction, and
detects as a third current value, a current value of the current on the input side of the inverter when the inverter applies the voltage so that the current flows in only the third direction, and
the controller detects the abnormality of the connection switching unit by comparing the first current value, the second current value, and the third current value to each other,
wherein, after the air conditioner receives an input to start an operation of the air conditioner, the fan is driven, and after the fan is driven and before the compressor is driven, the controller detects the abnormality of the connection switching unit.