Patent ID: 9423470
Filing Date: 2016-08-23
CPC Classification: G01R,H02K,H02P

Claim Text:
1. A control system for controlling a synchronous motor having a magnet in a rotor, the control system comprising: an inverter configured to output an AC current for driving the synchronous motor; a gate command generating unit configured to generate a gate command for controlling the inverter; a current detecting unit configured to detect the AC current output by the inverter; a magnetic pole position estimating unit configured to estimate a magnetic pole position based on the AC current detected by the current detecting unit and generate an estimation signal; a current command generating unit configured to generate a current command and an estimation command for controlling the inverter to output the AC current with a predetermined level, wherein the estimation command is generated when estimating the magnetic pole position; and a magnetic polarity determination unit configured to calculate, based on the estimation signal, first data indicating an inductance value based on a positive d-axis current and second data indicating an inductance value based on a negative d-axis current, compare the first data and the second data, and determine one of the first data and the second data having a larger value as indicating an N-pole direction; wherein the synchronous motor has a characteristic that: i) a d-axis inductance has a local maximum point within a range in which the positive d-axis current increases when the positive d-axis current is supplied to a stator, ii) a d-axis inductance in magnetic flux direction monotonically decreases when the positive d-axis current is increased beyond the local maximum point, and iii) the value of the local maximum point is greater than a value of the d-axis inductance when the negative d-axis current is supplied to the stator.