CPC H02K 16/02 (2013.01) [H02K 1/182 (2013.01); H02K 1/2798 (2022.01); H02P 6/153 (2016.02)] | 19 Claims |
1. A method comprising, at a motor controller:
during a first time period:
detecting a first operating speed of an electric motor comprising a set of coil assemblies;
detecting a torque demand of the electric motor;
estimating a first efficiency of a 120-degree commutation technique at the electric motor based on the first operating speed and the torque demand;
estimating a second efficiency of a 180-degree commutation technique at the electric motor based on the first operating speed and the torque demand;
setting a first operating speed threshold based on the first efficiency and the second efficiency;
in response to the first operating speed falling below the first operating speed threshold:
generating a first varying signal based on the 120-degree commutation technique; and
driving current through the set of coil assemblies according to the first varying signal;
detecting a second operating speed of the electric motor, the second operating speed exceeding the first operating speed; and
in response to the second operating speed exceeding the first operating speed threshold, initiating a first transition from the 120-degree commutation technique to the 180-degree commutation technique during a first transition period of a first transition duration;
during the first transition period:
generating a second varying signal based on a combination of:
the 120-degree commutation technique transitioning from a first duty rate to a second duty rate; and
the 180-degree commutation technique transitioning from the second duty rate to the first duty rate;
driving current through the set of coil assemblies according to the second varying signal; and
during a second time period succeeding the first time period, in response to completion of the first transition period:
generating a third varying signal based on the 180-degree commutation technique; and
driving current through the set of coil assemblies according to the third varying signal.
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