Patent ID: 11876477
Assignee: TECHNELEC LTD
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  G | IPC G  H

Claim 11:
12. A control system for an electrical motor comprising a rotor, a stator having a plurality of phase windings, and an inverter for applying voltage to the plurality of phase windings by connecting individual phase windings to a first or second voltage level, the control system configured:
to measure a first rate of change of current in a first phase winding, of said plurality of phase windings, connected to the first voltage level;
to measure a second rate of change of current in a second, different phase winding connected to the second voltage level;
to measure a third rate of change of current in a third, different phase winding connected to the second voltage level;
to calculate a difference between the first rate of change of current and a sum of the second and third rates of change of current to obtain an improved measurement of the first rate of change of current;
to use the improved measurement to obtain data related to a position of the rotor and to use the data related to the position of the rotor to determine the position of the rotor relative to the stator;
to operate the motor in a low speed regime; and
while operating in the low speed regime, to measure a stator current in the phase windings of the stator arising from an application of a stator voltage, and to calculate a motor characteristic of the electrical motor from positions of the rotor, the stator voltage, the stator current, and a resistance of the phase windings.