Systems and methods for estimating input power of an electric motor
AssigneeNidec Motor Corporation
InventorsPrakash B. Shahi, Robert J. Ploof, Jr.
Life of this patent
Estimating the term…
Abstract
A method of estimating an input power of a motor comprises determining an output power of the motor; determining a speed of the motor; calculating a scaling factor as a function of the speed of the motor; and estimating the input power as a function of the scaling factor and the output power.
Claims9
A computer-implemented method of estimating an input power of an electric motor system including a motor controller and an electric motor to improve controlling operation of the electric motor, the computer-implemented method comprising the following actions performed by the motor controller:
- determining an actual output power of the electric motor in which a torque is changing due to a load on the electric motor;
- determining a speed of the electric motor;
- calculating a scaling factor which is relevant to the input power of the electric motor system as a function of the speed of the electric motor, wherein the scaling factor is (−K1X2 +K2X +K3), where X is the speed of the electric motor, K1, K2, and K3 are constants;
- estimating the input power of the electric motor system as the actual output power multiplied by the scaling factor;
- and
- using the estimated input power to control operation of the electric motor as the torque is changing.
An electric motor system comprising:
- an electric motor including:
- a stator;
- a rotor rotatably coupled with the stator;
- a motor shaft rotatable with the rotor;
- and
- a motor controller for driving the electric motor, the motor controller having a non-transitory memory and a computer program stored in the non-transitory memory for improving controlling operation of the electric motor by performing the following steps:
- determining an actual output power of the electric motor in which a torque is changing due to a load on the electric motor;
- determining a speed of the electric motor;
- calculating a scaling factor which is relevant to the input power of the electric motor system as a function of the speed of the electric motor, wherein the scaling factor is (−K1X2+K2X +K3), where X is the speed of the electric motor, K1, K2, and K3 are constants;
- estimating the input power of the electric motor system as the actual output power multiplied by the scaling factor;
- and
- using the estimated input power to control operation of the electric motor as the torque is changing.
An electric motor system comprising:
- an electric motor including:
- an enclosure;
- a stator mounted in the enclosure;
- a rotor rotatably coupled with the stator;
- a motor shaft rotatable with the rotor;
- and
- a motor controller positioned in the enclosure for driving the electric motor, the motor controller having a non-transitory memory and a computer program stored in the non-transitory memory for improving controlling operation of the electric motor by performing the following steps:
- estimating an actual output power of the electric motor as a function of the speed of the motor and a torque of the motor in which the torque is changing due to a load on the electric motor;
- determining a speed of the electric motor;
- calculating a scaling factor which is relevant to the input power of the electric motor system as a function of the speed of the electric motor;
- estimating the input power of the electric motor system as the actual output power multiplied by the scaling factor, wherein the scaling factor is ((−2.4×10−5)X2+0.0606X+51.577), where X is the speed of the electric motor;
- and
- using the estimated input power to control operation of the electric motor as the torque is changing.
Dependencies are inferred from the claim text.