Patent ID: 9611851
Date: 2017-04-04
CPC Classifications: F04B,F04C

Claim:
1. A control device of an electric compressor comprising: an inverter circuit for outputting driving electric power to a DC motor of an electric compressor included in a refrigeration cycle; and an inverter controller for outputting a driving signal of the inverter circuit wherein the inverter controller includes: a target rotating speed setting means which sets a specified constant rotating speed as a target rotating speed of the DC motor; an actual measurement rotating speed obtaining means which obtains an actual measurement rotating speed which is a measurement value of a rotating speed of the DC motor, with a passage of time; a duty ratio adjusting means which adjusts a duty ratio of the driving electric power output from the inverter circuit so that the actual measurement rotating speed matches the target rotating speed; and a duty ratio change obtaining means which obtains a change in the duty ratio which occurs with a passage of time; wherein the target rotating speed setting means is configured to update the target rotating speed of the DC motor, based on the change in the duty ratio which occurs with a passage of time, wherein the duty ratio change obtaining means obtains a difference value between duty ratios set at different timings by the duty ratio adjusting means; wherein the target rotating speed setting means increases the target rotating speed based on the difference value between the duty ratios which is obtained by the duty ratio change obtaining means, and wherein the duty ratio change obtaining means includes: a duty ratio storage means which stores a first duty ratio obtained from the duty ratio adjusting means at a first timing; a time measuring means which measures time that passes from the first timing; and a duty ratio comparator means which compares a second duty ratio obtained from the duty ratio adjusting means at a second timing which is a specified time after the first timing, to the first duty ratio stored in the duty ratio storage means.