Apparatus and method of estimating inductance of permanent magnet synchronous motor

A method of estimating inductance of a permanent magnet synchronous motor (PMSM) comprising:

• injecting a random signal into one axis of a rotor coordinate system of the PMSM during sensorless operation;
• sensing change of current response to the injected signal while changing an inductance value used in control of the PMSM plural times during injection of the signal;
• and
• detecting an actual inductance value of the PMSM based on the sensed change of the current response.

An apparatus of estimating inductance of a permanent magnet synchronous motor (PMSM) comprising:

• an inverter to drive the PMSM;
• a current measurement unit to measure phase current of the PMSM;
• and
• an inductance estimation unit to inject a random signal into the axis of a rotor coordinate system of the PMSM during sensorless operation, change an inductance value used in control of the PMSM plural times during injection of the signal, respectively sense current responses to the injected signal during change of inductance plural times, detect the inductance value based on magnitudes of the sensed current responses, and judge the detected inductance value to be an actual inductance value of the PMSM.