Electric compressor

Abstract

An electric compressor includes: a compression part; an electric motor; and a controller. The controller includes a motor information detector for detecting a rotational speed and a power consumption of the electric motor, and is connected to a suction pressure sensor for detecting a suction pressure of a refrigerant and a discharge pressure sensor for detecting a discharge pressure of the refrigerant. The controller further includes: a memory for storing a map; an estimator; and an operation controller. The map indicates a correspondence between the suction pressure, the discharge pressure, the rotational speed, the power consumption, and dryness of the refrigerant to be drawn into the compression part. The estimator estimates the dryness of the refrigerant based on the map using the rotational speed and the power consumption, the suction pressure, and the discharge pressure. The operation controller controls an operation of the electric motor according to the dryness.

What is claimed is: 
     
         1 . An electric compressor comprising:
 a compression part configured to compress a refrigerant;   an electric motor configured to drive the compression part; and   a controller configured to control the electric motor, the controller including a motor information detector configured to detect a rotational speed and a power consumption of the electric motor, the controller being connected to a suction pressure sensor for detecting a suction pressure of the refrigerant to be drawn into the compression part and a discharge pressure sensor for detecting a discharge pressure of the refrigerant discharged from the compression part, wherein   the controller includes:
 a memory for storing a map that indicates a correspondence between the suction pressure, the discharge pressure, the rotational speed, the power consumption, and dryness of the refrigerant to be drawn into the compression part; 
 an estimator configured to estimate the dryness of the refrigerant based on the map using the rotational speed and the power consumption detected by the motor information detector, the suction pressure detected by the suction pressure sensor, and the discharge pressure detected by the discharge pressure sensor; and 
 an operation controller configured to control an operation of the electric motor according to the dryness estimated by the estimator. 
   
     
     
         2 . The electric compressor according to  claim 1 , wherein
 the estimator estimates the dryness of the refrigerant after a predetermined time has elapsed since the electric motor was activated.   
     
     
         3 . The electric compressor according to  claim 1 , wherein
 the operation controller stops the electric motor when the dryness estimated by the estimator is outside a predetermined range.   
     
     
         4 . The electric compressor according to  claim 1 , wherein
 the electric compressor includes a housing for accommodating the compression part, the electric motor, and the controller, the housing having:
 a suction port through which the refrigerant to be compressed by the compression part is drawn into the housing; and 
 a discharge port through which the refrigerant compressed by the compression part is discharged from the housing, 
   the suction pressure sensor is disposed at the suction port, and   the discharge pressure sensor is disposed at the discharge port.