Stall detection in field-oriented sensorless motor control
AssigneeBlack & Decker Inc.
InventorMehdi RAMEZANI
Life of this patent
Estimating the term…
Abstract
A controller for operating a brushless motor comprising a stator and a rotor is configured to: operate a sliding-mode observer (SMO) process detect an angular position of the rotor; predict an occurrence of a stall condition based on at least one of a rotational speed of the rotor or the phase current of the motor; operate a high-frequency injection (HFI) process in response to predicting the occurrence of the stall condition to determine the angular position of the rotor; determine whether the stall condition has occurred; and transition from the SMO process to the HFI process in response to the determination of the stall condition has occurred. In an embodiment, a power tool is provided including a motor and a controller as described above.
Claims15
A power tool comprising:
- a housing;
- a brushless motor disposed within the housing, the motor comprising a stator having a plurality of windings and a rotor;
- a power switch circuit that supplies power from a power source to the brushless motor;
- and
- a controller configured to apply a drive signal to the power switch circuit to control the supply of power to the brushless motor, wherein the controller is configured to:
- operate a sliding-mode observer (SMO) process to estimate a back electromotive force (back-EMF) voltage of the motor based on a phase current of the motor and detect an angular position of the rotor based on the estimated back-EMF voltage;
- predict an occurrence of a stall condition based on at least one of a rotational speed of the rotor or the phase current of the motor;
- operate a high-frequency injection (HFI) process in response to predicting the occurrence of the stall condition, wherein the HFI process includes injecting a plurality of voltage pulses to the motor and detecting corresponding high-frequency current components to determine the angular position of the rotor;
- determine whether the stall condition has occurred;
- and
- transition from the SMO process to the HFI process in response to the determination of the stall condition has occurred.
A method of operating a brushless motor comprising a stator having a plurality of windings and a rotor, the method comprising:
- operating a sliding-mode observer (SMO) process to estimate a back electromotive force (back-EMF) voltage of the motor based on a phase current of the motor and detect an angular position of the rotor based on the estimated back-EMF voltage;
- predicting an occurrence of a stall condition based on at least one of a rotational speed of the rotor or the phase current of the motor;
- operating a high-frequency injection (HFI) process in response to predicting the stall condition, wherein the HFI process includes injecting a plurality of voltage pulses to the motor and detecting corresponding high-frequency current components to determine the angular position of the rotor;
- determining whether the stall condition has occurred;
- and
- transitioning from the SMO process to the HFI process in response to the determination of the stall condition has occurred.
A controller for operating a brushless motor comprising a stator having a plurality of windings and a rotor, the controller being configured to:
- operate a sliding-mode observer (SMO) process to estimate a back electromotive force (back-EMF) voltage of the motor based on a phase current of the motor and detect an angular position of the rotor based on the estimated back-EMF voltage;
- predict an occurrence of a stall condition based on at least one of a rotational speed of the rotor or the phase current of the motor;
- operate a high-frequency injection (HFI) process in response to predicting the occurrence of the stall condition, wherein the HFI process includes injecting a plurality of voltage pulses to the motor and detecting corresponding high-frequency current components to determine the angular position of the rotor;
- determine whether the stall condition has occurred;
- and
- transition from the SMO process to the HFI process in response to the determination of the stall condition has occurred.
Dependencies are inferred from the claim text.