Texas Instruments DRV8313 Evaluation Module DRV8313EVM DRV8313EVM データシート
製品コード
DRV8313EVM
RUNNING THE APPLICATION
4.3
Enable Motor
Once the parameters are set, clicking the checkbox should start the motor. Clicking the checkbox again
will stop the motor.
will stop the motor.
Figure 9. Settings Tab
4.3.1
Start-Up Process
In order to start and run the BLDC motor, the control algorithm applies the “align and go” method.
•
Align State: The main aim of alignment is to align the rotor to a known position. This is done by
energizing two of motor phases for pre-fixed duty cycle to generate standstill stator magnetic field for
certain duration. This known position is necessary to start rotation in the proper direction and to
generate maximum torque at startup.
energizing two of motor phases for pre-fixed duty cycle to generate standstill stator magnetic field for
certain duration. This known position is necessary to start rotation in the proper direction and to
generate maximum torque at startup.
•
Go State: Once the alignment is done, the control algorithm applies the next appropriate voltage vector
sequence to produce the stator magnetic field, which is in 90 degree advance to the rotor flux, in order
to produce maximum torque at starting. At the same instant the back e-mf integration of non-excited
phase is initiated and the next commutation event occurs once the back-emf integration threshold is
reached and the process continues for the smooth rotation of motor.
sequence to produce the stator magnetic field, which is in 90 degree advance to the rotor flux, in order
to produce maximum torque at starting. At the same instant the back e-mf integration of non-excited
phase is initiated and the next commutation event occurs once the back-emf integration threshold is
reached and the process continues for the smooth rotation of motor.
Startup Duty Cycle: Changing the value of the startup duty cycle will change the applied duty cycle
during alignment state. Typical value can very from 10% to 30% depending upon the motor load and
inertia.
during alignment state. Typical value can very from 10% to 30% depending upon the motor load and
inertia.
Startup Ramp-up Time: During alignment state of the motor, this ramp-up time defines time duration for
which two of the motor phases remain active for alignment; i.e. its simply align state time duration. Please
note that initial rotor will experience oscillation when it first moves to get aligned with stator applied field
and try to get locked with it. The oscillation time depends upon the mechanical time constant of motor load
and inertia. It is very important that before applying ‘go state” rotor oscillation dies down sufficiently to
avoid commutation failure. Startup ramp-up time helps to change the timing of align state for different
motors to make sure that rotor oscillation have died down and rotor has come very near to standstill.
which two of the motor phases remain active for alignment; i.e. its simply align state time duration. Please
note that initial rotor will experience oscillation when it first moves to get aligned with stator applied field
and try to get locked with it. The oscillation time depends upon the mechanical time constant of motor load
and inertia. It is very important that before applying ‘go state” rotor oscillation dies down sufficiently to
avoid commutation failure. Startup ramp-up time helps to change the timing of align state for different
motors to make sure that rotor oscillation have died down and rotor has come very near to standstill.
Pole Count: The number of poles of the motor entered here will be used for the speed calculations.
11
SLVU815 – November 2012
DRV8313EVM User’s Guide
Copyright © 2012, Texas Instruments Incorporated