AN1913D Freescale Semiconductor / Motorola, AN1913D Datasheet - Page 53

• Manufacturer Part Number: AN1913D
• Description: 3-phase BLDC Motor Control with Sensorless Back-EMF ADC Zero Crossing Detection using DSP 56F80x
• Manufacturer: Freescale Semiconductor / Motorola

10.2.3 Minimal Zero Commutation of Starting (Back-EMF Acquisition) State
#define x_MIN_ZCROSOK_START
Notes: It is recommended to use only the value 0x02 or 0x03. If this constant is set too high, the motor
10.2.4 Wrong Zero Crossing
#define x_MAX_ZCROSERR 0x04 /*Maximal Zero Crossing Errors (to stop commutations) */
Notes: During tuning of the software for other motors, this constant can temporarily be enlarged.
10.2.5 Commutation Proceeding Period
#define x_CONST_PERPROCCMT_US 170.0 /* Period of Commutation proceeding [micros]*/
Notes: This constant needs to be lower then 1/3 of the (minimal) commutation period at motor maximal
10.2.6 Commutation Timing Setting
Notes: Normally these structures do not require change. If the constants described in this section need to
x_StartComputInit
x_RunComputInit
Coef_CmtPrecompLShft
Coef_CmtPrecompFrac
This constant x_MIN_ZCROSOK_START determines the minimal number of Zero Crossing OK
commutation to finish the BLDC starting phase.
The constant
stops and starts the motor whenever successive
Zero Crossings) appear.
The Commutation proceeding period is the constant time after motor commutation; when Back-EMF
Zero Crossing is not measured (commutation current decay period).
The unit of this constants is 1 s.
If it is required to change the motor commutation advancing (retardation) the coefficients in starting
and running structures needs to be changed:
Both structures are in bldcadczcdefines.h.
The x_StartComputInit structure is used by the application software during Starting state (see
Section
The x_RunComputInit structure is used by the application software during Running state see
Section
fractional and scaling part of Coef_CmtPrecomp
final Coef_CmtPrecomp = Coef_CmtPrecompFrac << Coef_CmtPrecompLShft
control does not enter the Running state fast enough.
speed.
be changed, a detailed study of the control principle needs to be studied (see
MotorControl.pdf).
5.4.3).
5.4.3.1).
x_MAX_ZCROSERR
BLDC control with BEMF Zero Crossing using ADC
Freescale Semiconductor, Inc.
For More Information On This Product,
is used for control of commuting problems. The application software
0x02
Go to: www.freescale.com
/* minimal Zero Crossing OK commutation
x_MAX_ZCROSERR
to finish BLDC starting phase */
Setting of Software Parameters for Other Motors
commutations (with problematical
Section 5
and
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