Angle/Frequency Selector in an Electric Motor Controller Architecture
AssigneeTexas Instruments Incorporated
InventorDavid Patrick Magee
Life of this patent
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Abstract
A motor controller architecture and method of operating the same. The motor controller includes a function for estimating the low speed operation of the motor, for example by evaluating the response to a periodic excitation signal injected into the control loop of the controller architecture. A periodic excitation signal in the form of a square wave allows for analysis of the response of the motor without requiring demodulation, which allows the frequency of the excitation signal to be above the audible range. Control logic for controlling the motor at transitional speeds between low speed control and high speed (back emf) control is provided in some embodiments.
Claims23
A controller for a rotating AC electric machine, comprising:
- drive circuitry, for driving a multiphase electric machine responsive to at least one control signal;
- feedback circuitry for producing feedback signals responsive to electrical values received from at least one sensor at the machine;
- a control loop for producing the at least one control signal to the drive circuitry responsive to a feedback velocity signal and to an input reference signal;
- a low speed state estimator function for estimating a low speed velocity of the machine from the feedback signals;
- a high speed state estimator for estimating a high speed velocity of the machine from the feedback signals;
- and
- a selector function, having inputs receiving the low speed and high speed velocity estimates and receiving the input reference signal, and having an output for presenting the feedback velocity signal to the control loop, comprising:
- sequential logic for determining a selection state responsive to a previous selection state and to the input reference signal;
- and
- a selector for producing the feedback velocity signal corresponding to a selected one of either the high speed velocity estimate or the low speed velocity estimate, the selection made responsive to the selection state determined by the sequential logic.
A method of controlling the operation of a rotating AC machine, comprising:
- driving the electric machine responsive to a control signal;
- producing feedback signals responsive to sensed rotation of the machine;
- generating the control signal by:
- determining a current selection state;
- responsive to the determined state being a low-speed state:
- estimating a low-speed velocity from the feedback signals;
- and
- producing the control signal by executing a control function on the estimated low-speed velocity and an input reference signal;
- responsive to the determined state being a high-speed state:
- estimating a high-speed velocity from the feedback signals;
- and
- producing the control signal by executing a control function on the estimated low-speed velocity and an input reference signal.
Dependencies are inferred from the claim text.