Method for avoiding stalled motor in a stand mixer with sensorless BLDC drive
A method for operating an appliance, such as a stand mixer, is provided. In one example implementation, the method can include operating a motor of the appliance in a first direction. The method can further include detecting, by a feedback system of the appliance, a first trigger condition. The method can further include, responsive to detecting the first trigger condition, operating the motor of the appliance in a second direction that is different than the first direction.
1. A method for operating an appliance, the method comprising:
operating a motor of the appliance in a first direction;
detecting, via a sensorless feedback system, a first trigger condition; and
responsive to detecting the first trigger condition, operating the motor of the appliance in a second direction, the second direction being different than the first direction.
2. The method of claim 1 , further comprising:
detecting, via the sensorless feedback system, a second trigger condition; and
responsive to detecting the second trigger condition, operating the motor of the appliance in the first direction.
3. The method of claim 2 , wherein the second trigger condition comprises an expiration of a period of time.
4. The method of claim 1 , wherein the first trigger condition is indicative of a stall condition in the motor.
5. The method of claim 1 , wherein the first trigger condition is based on a speed of the motor dropping below a speed threshold.
6. The method of claim 1 , wherein detecting the first trigger condition further comprises:
detecting a target speed of the motor is within a threshold window; and
responsive to detecting the target speed of the motor being within the threshold window, decreasing, via a controller of the sensorless feedback system, the target speed of the motor to about zero revolutions-per-minute.
7. The method of claim 6 , wherein decreasing the target speed of the motor to about zero revolutions-per-minute comprises decreasing the target speed of the motor in a stepped manner.
8. The method of claim 6 , wherein decreasing the target speed of the motor to about zero revolutions-per-minute comprises decreasing the target speed of the motor in a linear manner.
9. The method of claim 1 , further comprising:
responsive to detecting the second trigger condition and operating the motor of the appliance in the first direction, detecting, via the sensorless feedback system, a third trigger condition; and
responsive to detecting the third trigger condition, operating the motor of the appliance in the second direction,
wherein the third trigger condition is indicative of a stall condition of the motor.
10. The method of claim 1 , wherein the sensorless feedback system comprises a back-EMF observer, the back-EMF observer configured to provide data indicative of a position or a speed of the motor.
11. The method of claim 1 , wherein:
the first direction is a clockwise direction; and
the second direction is a counterclockwise direction.
12. A stand mixer appliance, comprising:
a base;
a housing pivotally mounted to the base;
a motor assembly comprising a motor disposed within the housing;
a mixer shaft rotatably mounted on the housing; and
a controller operably coupled to the motor, the controller configured to:
operate the motor in a first direction;
detect a first trigger condition; and
operate the motor in a second direction in response to detecting the first trigger condition, wherein the first direction is different than the second direction.
13. The stand mixer appliance of claim 12 , wherein the controller is further configured to:
detect a second trigger condition; and
operate the motor in the first direction in response to detecting the second trigger condition.
14. The stand mixer of claim 12 , wherein the first trigger condition is indicative of a stall condition of the motor.
15. The stand mixer appliance of claim 12 , wherein the motor is a brushless direct current (BLDC) motor.
16. The stand mixer appliance of claim 12 , wherein the motor is a permanent magnet synchronous motor (PMSM).
17. The stand mixer appliance of claim 12 , wherein:
the controller further comprises a back-EMF observer configured to provide data indicative of a position or a speed of the motor; and
the controller is configured to implement a field-oriented control (FOC) control scheme.
18. A motor assembly for a stand mixer, the motor assembly comprising:
a motor, the motor comprising at least a rotor;
a motor drive;
a sensorless feedback system configured to obtain feedback measurements of one or more electrical characteristics from the motor; and
a controller operably coupled to the motor, the controller configured to:
operate the motor in a first direction;
detect a first trigger condition; and
operate the motor in a second direction in response to detecting the first trigger condition, wherein the first direction is different than the second direction.
19. The motor assembly of claim 18 , wherein the controller is further configured to:
detect a second trigger condition; and
operate the motor in the first direction in response to detecting the second trigger condition.
20. The motor assembly of claim 18 , wherein:
the motor is a brushless DC (BLDC) motor; and
the sensorless feedback system comprises a back-EMF observer, the back-EMF observer configured to provide data indicative of a position or a speed of the motor.