AN1914 Freescale Semiconductor / Motorola, AN1914 Datasheet - Page 50

• Manufacturer Part Number: AN1914
• Description: 3-Phase BLDC Motor Control with Sensorless Back EMF Zero Crossing Detection Using DSP56F80x
• Manufacturer: Freescale Semiconductor / Motorola

Setting of SW parameters for other motor kits
#define x_CURR_PI_PROPORTIONAL_GAIN 30000
#define x_CURR_PI_PROPORTIONAL_GAIN_SCALE 24
#define x_CURR_PI_INTEGRAL_GAIN
#define x_CURR_PI_INTEGRAL_GAIN_SCALE 23
Notes:
Notes:
11.2 Commutation Control Settings
11.2.1 Alignment Period
#define x_PER_ALIGNMENT_S
Notes:
11.2.2 Start-up Periods
#define x_PER_CMTSTART_US
#define x_PER_TOFFSTART_US
50
The current controller works with constant execution (sampling) period determined by PWM
frequency:
Current Controller period = 1/pwm frequency.
Both proportional and integral gain have two coefficients: gain portion and scale
Current Proportional gain:
Current Integral gain:
The PI controller proportional and integral constants can be set experimentally.
In order to get the motor reliably started the commutation control constants must be properly set.
The time duration of alignment stage must be long enough to stabilize the rotor before it starts.
This is set in seconds in bldcadczcdefines.h.
The constants defining the start up need to be changed according to drive dynamic.
All this section settings are in bldcadczcdefines.h:
The unit of these constants is 1 s.
x_PER_CMTSTART_US
x_PER_TOFFSTART_US
is not sensed.
The older versions of the software (SDK 2.2) used the constants with system units:
If the overcurrent fault is experienced during Alignment stage, then it is recommended to slow
down the regulator. If the yy_GAIN_SCALE is increased, the gain is decreased.
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_SCALE
x_CURR_PI_INTEGRAL_GAIN_SCALE
For first tuning it is recommended to set this period high enough (e.g. 5s). Then, if the motor
works well it can be significantly lowered (e.g. 0.1s).
DSP56F80x MC PWM Module in Motor Control Applications
is the commutation period used to compute the first (start) commutation period.
is the first (start) Toff interval after commutation where BEMF Zero Crossing
Freescale Semiconductor, Inc.
For More Information On This Product,
x_CURR_PI_PROPORTIONAL_GAIN,
14400.0
Go to: www.freescale.com
19000
7200.0
0.5
) using the formulae in the comments
/* Alignment period [s] */
(resp.
/* Start Commutation Period [micros] */
/* Start Zero Crossing
/* integral gain portion */
/* integral gain gain scale */
/* proportional gain portion */
/* proportional gain scale*/
x_CURR_PI_INTEGRAL_GAIN,
Toff Period [micros] */