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US 8,575,772 B2Granted
Permanent magnet machine control system
AssigneeGeneral Electric Company
InventorsDavid Smith, Anthony Michael Klodowski
Life of this patent
Estimating the term…
Abstract
A permanent magnet (PM) machine system is provided having a PM machine and a controller in communication with the PM machine. The PM machine has a q-axis voltage feedback signal and a pullout torque that represents a peak torque that the PM machine generates. The controller includes a q-axis current regulator that produces a commanded q-axis voltage that is supplied to the PM machine. The controller also includes at least one control logic for monitoring the q-axis voltage feedback signal of the PM machine.
Claims20
A permanent magnet (PM) machine system, comprising:
- a PM machine having a q-axis voltage feedback signal and a pullout torque that represents a peak torque that the PM machine generates;
- a controller in communication with the PM machine, the controller including:
- at least one control logic for monitoring the q-axis voltage feedback signal of the PM machine to determine a machine flux;
- at least one control logic for calculating a torque producing current limit based on at least the determined machine flux, the torque producing current limit representing the peak torque producing current the PM machine operates at before surpassing the pullout torque value;
- at least one control logic for limiting a q-axis current command using the torque producing current limit such that the q-axis current command does not substantially exceed the torque producing current limit;
- and
- a q-axis current regulator that receives the limited q-axis current command to produce a commanded q-axis voltage that is supplied to the PM machine.
4 more elements
A wind power plant, comprising:
- a wind turbine;
- a gearbox connected to the wind turbine through a shaft;
- a power convertor;
- a permanent magnet (PM) machine connected to the power converter, the shaft transferring energy from the wind turbine to the PM machine through the gearbox, the PM machine having a q-axis voltage feedback signal, a d-axis voltage feedback signal, and a pullout torque that represents a peak torque that the PM machine generates;
- a controller in communication with the PM machine and the power converter, the controller included with the power converter, the controller including:
- a q-axis current regulator that produces a commanded q-axis voltage that is supplied to the PM machine;
- a d-axis current regulator that produces a commanded d-axis voltage that is supplied to the PM machine;
- a voltage based flux model that receives the q-axis voltage feedback signal, the d-axis voltage feedback signal, and a frequency of the PM machine, and wherein the voltage based flux model includes control logic for determining a q-axis flux feedback and a d-axis flux feedback;
- a q-axis machine inductance estimator for calculating an adapted q-axis inductance, wherein the q-axis machine inductance estimator receives the q-axis flux feedback from the voltage based flux model, a q-axis machine current feedback, and an adjusted value of q-axis machine impedance;
- a voltage limiter that receives the frequency and a voltage limit set point and calculates a net commanded flux magnitude, wherein the net commanded flux magnitude is calculated by determining a nominal flux magnitude and the voltage limit set point divided by the frequency, and selects the lesser of the two values as the net commanded flux magnitude;
- at least one control logic for monitoring the q-axis voltage feedback signal and the d-axis voltage feedback signal of the PM machine;
- at least one control logic for calculating a torque producing current limit, the torque producing current limit representing the peak torque producing current the PM machine operates at before surpassing the pullout torque value, wherein the torque producing current limit is based on at least the q-axis voltage feedback signal;
- at least one control logic for calculating a preliminary q-axis current command and a d-axis current command, the preliminary q-axis current command based on at least the q-axis voltage feedback signal and the d-axis current command based on at least the d-axis voltage feedback signal;
- a current command calculator to calculate the d-axis current command and the preliminary q-axis current command, the adapted q-axis inductance from the q-axis estimator and the d-axis flux feedback from the voltage based flux model inputted into the current command calculator;
- at least one control logic for comparing the preliminary q-axis current command and the torque producing current limit;
- at least one control logic for limiting a q-axis current command sent to the q-axis current regulator such that the q-axis current command does not substantially exceed the torque producing current limit;
- and
- at least one control logic for sending the d-axis current command to the d-axis current regulator.
15 more elements
Dependencies are inferred from the claim text.