User Manual

References
3-Phase BLDC Motor Control with Sensorless Back-EMF, ADC, Zero Crossing, Rev. 3
56 Freescale Semiconductor
Preliminary
If you also request to change the minimal motor speed, then you need to set minimal angular speed
#define x_OMEGA_MIN_SYSU 4096 /* angular frequency minimal [system unit] */
Notes: Remember that minimal angular speed is not in radians, but in system units! Where 32768 is the maximal
speed done by
x_SPEED_ROTOR_MAX_RPM
The speed PI regulator constants can be tuned as described below. All settings can be found in
bldcadczcdefines.h.
The execution period of the speed controller is set by:
#define PER_SPEED_SAMPLE_S 0.001 /* Sampling Period of the Speed Controller [s] */
Both proportional and integral gain has two coefficients: portion and scale!
Speed Proportional gain:
#define x_SPEED_PI_PROPORTIONAL_GAIN 22000 /* speed proportional gain portion*/
#define x_SPEED_PI_PROPORTIONAL_GAIN_SCALE 19 /* speed proportional gain scale*/
Speed Integral gain:
#define x_SPEED_PI_INTEGRAL_GAIN 27500 /* speed integral gain portion */
#define x_SPEED_PI_INTEGRAL_GAIN_SCALE 23 /* speed integral gain gain scale */
The PI controller proportional and integral constants can be set experimentally.
Notes: If the motor has problems when requested speed is changed, then it is recommended to slow down the
regulator. If the yy_GAIN_SCALE is increased, the gain is decreased!
There are also the coefficients x_SPEED_PI_PROPORTIONAL_GAIN_REAL (resp.
x_SPEED_PI_INTEGRAL_TI_REAL), which are not directly used for regulator setting, but can be used to
count
x_SPEED_PI_PROPORTIONAL_GAIN, x_SPEED_PI_PROPORTIONAL_GAIN_SCALE (resp.
x_SPEED_PI_INTEGRAL_GAIN, x_SPEED_PI_INTEGRAL_GAIN_SCALE) using the formulae in the comments!
11. References
11.1 Software Development Kit, SDK rev.2.3
• Targetting_DSP56805_Platform.pdf
— located at:
Embedded SDK\help\docs\sdk\targets\Targetting_DSP56805_Platform\content
• Targetting_DSP56803_Platform.pdf
— located at:
Embedded SDK\help\docs\sdk\targets\Targetting_DSP56803_Platform\content
• Motor Control.pdf, chapter BLDC motor commutation with Zero Crossing sensing
— located at: Embedded SDK\help\docs\sdk\libraries\motorcontrol\content