Method and system for controlling a motor

1. A method for controlling a motor configured to provide propulsion for a mobile platform, the method comprising:

determining whether to activate a preheat mode based on a temperature of a motor; and

upon determining to activate the preheat mode, controlling a preheat current provided to the motor to enable self-preheating of the motor, the preheat current including a D-axis current, wherein:

the D-axis current is calculated using a proportional gain and an integral gain of a proportional-integral (IP) model based on the temperature of the motor;

the proportion gain is determined by controlling the self-preheating of the motor individually using a plurality of proportion gains, and selecting one of the plurality of proportion gains that raises the temperature of the motor to a steady state within a predetermined first time duration; and

the integral gain is determined by controlling the self-preheating of the motor individually using a plurality of integral gains and the proportion gain, and selecting one of the plurality of integral gains that raises the temperature of the motor to a target temperature at the steady state within a predetermined second time duration.

2. The method of claim 1 , wherein determining whether to activate the preheat mode based on the temperature of the motor includes:

determining to activate the preheat mode upon determining the temperature of the motor is less than the target temperature; and

determining not to activate the preheat mode upon determining the temperature of the motor is greater than or equal to the target temperature.

3. The method of claim 1 , wherein the preheat current further comprises a Q-axis current.

4. The method of claim 3 , wherein the Q-axis current is equal to zero.

5. The method of claim 3 , wherein the D-axis current and the Q-axis current are converted to a three-phase supply current via an inverse direct-quadrature-zero transformation.

6. The method of claim 1 , wherein the D-axis current is selected to increase the temperature of the motor to the target temperature within a target preheat duration.

7. The method of claim 1 , wherein the temperature of the motor is obtained further based on an environmental temperature measured via a temperature sensor.

8. The method of claim 1 , further comprising:

controlling conversion of an input current provided by a power device onboard the mobile platform into the preheat current.

9. The method of claim 8 , wherein the power device and the motor are preheated simultaneously.

10. The method of claim 8 , wherein the preheat current is less than or equal to a maximum current based on performance parameters of the power device.

11. The method of claim 1 , further comprising:

receiving a preheat request from a remote control device; and

determining whether to activate the preheat mode in response to the preheat request, including:

accepting the preheat request upon determining to activate the preheat mode; or

rejecting the preheat request upon determining not to activate the preheat mode.

12. The method of claim 1 , further comprising:

notifying a remote control device of a preheat status of the motor.

13. The method of claim 1 , wherein the mobile platform includes an unmanned aerial vehicle (UAV).

14. The method of claim 1 , further comprising:

obtaining the temperature of the motor based on a resistance of the motor and a temperature-resistance correlation of the motor.

15. A system for controlling a motor configured to provide propulsion for a mobile platform, the system comprising:

a controller configured to:

determine whether to activate a preheat mode based on a temperature of a motor; and

upon determining to activate the preheat mode, control a preheat current provided to the motor to enable self-preheating of the motor, the preheat current including a D-axis current, wherein:

the D-axis current is calculated using a proportional gain and an integral gain of a proportional-integral (IP) model based on the temperature of the motor;

the proportion gain is determined by controlling the self-preheating of the motor individually using a plurality of proportion gains, and selecting one of the plurality of proportion gains that raises the temperature of the motor to a steady state within a predetermined first time duration; and

the integral gain is determined by controlling the self-preheating of the motor individually using a plurality of integral gains and the proportion gain, and selecting one of the plurality of integral gains that raises the temperature of the motor to a target temperature at the steady state within a predetermined second time duration.

16. A mobile platform comprising:

a motor configured to provide propulsion for the mobile platform; and

a controller configured to:

determine whether to activate a preheat mode based on the obtained a temperature of a motor; and

upon determining to activate the preheat mode, control a preheat current provided to the motor to enable self-preheating of the motor, the preheat current including a D-axis current, wherein:

the D-axis current is calculated using a proportional gain and an integral gain of a proportional-integral (IP) model based on the temperature of the motor;

the proportion gain is determined by controlling the self-preheating of the motor individually using a plurality of proportion gains, and selecting one of the plurality of proportion gains that raises the temperature of the motor to a steady state within a predetermined first time duration; and

the integral gain is determined by controlling the self-preheating of the motor individually using a plurality of integral gains and the proportion gain, and selecting one of the plurality of integral gains that raises the temperature of the motor to a target temperature at the steady state within a predetermined second time duration.