Motor controller
AssigneeOkuma Corporation
InventorSatoshi Eguchi
Life of this patent
Estimating the term…
Abstract
A controller for a motor determines a voltage limit circle based on a velocity of the motor, a DC bus voltage of an inverter, calculates a q axis current limit value based on the voltage limit circle and a predetermined current limit circle, determines, as a q axis current command value, a value obtained through a limit process which is applied using the q axis current limit value to a q axis current value calculated in accordance with a torque command value, and determines a corresponding d axis current value based on the q axis current command value.
Claims6
A motor controller wherein a current supplied through an inverter to a motor is computed using a two-phase rotating coordinate system, the motor controller comprising:
- a q axis current calculator which calculates a q axis current value in accordance with a torque command value;
- and
- a current vector controller which computes a q axis current command value and a d axis current command value based on the q axis current value, a velocity of the motor, and a DC bus voltage of the inverter;
- wherein
- the current vector controller is configured to
- determine, based on the velocity of the motor and the DC bus voltage, a voltage limit circle representing, on a d-q plane, current limit values defined by a voltage constraint resulting from the DC bus voltage,
- calculate a q axis current limit value based on both the voltage limit circle and a previously determined current limit circle representing, on the d-q plane, current limit values defined by a current constraint of the motor,
- determine, as a q axis current command value, a value obtained through limit processing which is applied using the q axis current limit value to the q axis current value calculated in the q axis current calculator, and
- determine a corresponding d axis current command value based on the q axis current command value.
Dependencies are inferred from the claim text.