User Manual

Setting of Software Parameters for Other Motors
3-Phase BLDC Motor Control with Sensorless Back-EMF, ADC, Zero Crossing, Rev. 3
52 Freescale Semiconductor
Preliminary
10.1 Current and Voltage Settings
10.1.1 DC-Bus Voltage, Maximal and Minimal Voltage and Current Limit Settings
For the right regulator settings, it is required to set the expected DC-Bus voltage in bldcadczcdefines.h:
#define x_VOLT_DC_BUS 12.0 /* DC-Bus expected voltage */
The current voltage limits for software protection are:
#define x_DCB_UNDERVOLTAGE 3.0 /* Undervoltage limit [V] */
#define x_DCB_OVERVOLTAGE 15.8 /* Overvoltage limit [V] */
#define x_DCB_OVERCURRENT 48.0 /* Overcurrent limit [A] */
Notes: Note the hardware protection with setting of pots R116, R71 for 56F805EVM or R40, R45 for
56F803EVM (see EVM manuals for details)
10.1.2 Alignment Current and Current Regulator Setting
All settings in this section are in bldcadczcdefines.h.
The current during the Alignment state (before the motor starts) is recommended to be set to the current
nominal motor value:a
#define x_CURR_ALIGN_DESIRED_A 17.0 /* Alignment Current Desired [A] */
Usually it is necessary to set the PI regulator constants. (The PI regulator is described in algorithm
controllerPItype1 description in SDK doc).
The current controller works with a constant execution (sampling) period determined by the PWM frequency:
Current Controller period = 1/pwm frequency.
Both proportional and integral gain have two coefficients: gain portion and scale.
Current Proportional gain:
#define x_CURR_PI_PROPORTIONAL_GAIN 30000 /* proportional gain portion */
#define x_CURR_PI_PROPORTIONAL_GAIN_SCALE 24 /* proportional gain scale*/
Current Integral gain:
#define x_CURR_PI_INTEGRAL_GAIN 19000 /* integral gain portion */
#define x_CURR_PI_INTEGRAL_GAIN_SCALE 23 /* integral gain gain scale */
The PI controller proportional and integral constants can be set experimentally.
Notes: If the overcurrent fault is experienced during the Alignment state, then it is recommended to slow
down the regulator. If the yy_GAIN_SCALE is increased, the gain is decreased.
Notes: The coefficients x_CURR_PI_PROPORTIONAL_GAIN_REAL (resp.
x_CURR_PI_INTEGRAL_TI_REAL) are not directly used for regulator setting, but can be used to
calculate the
x_CURR_PI_PROPORTIONAL_GAIN, x_CURR_PI_PROPORTIONAL_GAIN_SCALE (resp.
x_CURR_PI_INTEGRAL_GAIN, x_CURR_PI_INTEGRAL_GAIN_SCALE) using the formulae in the
comments.