CPC H02P 6/182 (2013.01) [H02P 6/20 (2013.01); H02P 2203/03 (2013.01)] | 16 Claims |
1. A semiconductor device for controlling a three-phase motor, the semiconductor device comprising:
a detection circuit coupled to output nodes corresponding to each phase of the three-phase motor, and configured to detect a voltage generated in the output node of a non-energized phase of the three-phase motor; and
a controller configured to:
at a time of starting the three-phase motor, apply a drive voltage to any two phases of the three-phase motor based on an estimated magnetic pole position of a rotor in a stop state; and
estimate a position of the rotor based on a difference voltage between i) a voltage generated in the output node of the non-energized phase during a drive voltage applying period and ii) a voltage generated in the output node of the non-energized phase during a regeneration period immediately after or immediately before the drive voltage applying period,
wherein, when an absolute value of the difference voltage is less than or equal to a first threshold, the controller switches the phase the drive voltage applying.
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