AN1913 Motorola / Freescale Semiconductor, AN1913 Datasheet - Page 39

• Manufacturer Part Number: AN1913
• Description: AN1913 3-phase BLDC Motor Control with Sensorless Back-EMF ADC Zero Crossing Detection using DSP 56F80x
• Manufacturer: Motorola / Freescale Semiconductor

7.2.6 Process Current PI Controller
7.2.7 Process PWM Generation
7.2.8 Process Fault Control
7.3 State Diagram
7.3.1 Main Software States - General Overview
The speed controller works with a constant execution (sampling) period. The request is driven from a
timer interrupt with the constant PER_SPEED_SAMPLE_S. The PI controller proportional and
integral constants were set experimentally.
The process is similar to the Speed controller. The I_Dc_Bus current is controlled based on the
U_Dc_Bus_Desired Reference current. The current controller is processed only during the Alignment
state.
The current controller works with a constant execution (sampling) period which is determined by the
following PWM frequency:
Current Controller period = 1/pwm frequency.
The PI controller proportional and integral constants were set experimentally.
The Process PWM Generation creates the following:
The Process Fault Control is used for drive protection (see
passed to the PWM Generation process and to the Application State Machine process in order to
disable the PWMs and to control the application accordingly.
All the software state diagrams are described below.
The software can be split into the following processes:
For detailed information, refer to
State Diagram - Process Application State Machine; which is the highest level. (Only the process Fault
Control is on the same level because of the motor emergency stop.)
The status of all the processes after reset is defined in
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BLDC motor commutation pattern as described in
Required duty cycle
Process Application State Machine
Process Commutation Control
Process ADC Zero Crossing Checking
Process Zero Crossing Offset Setting
Process Speed PI Controller
Process Current PI Controller
Process PWM Generation
Process Fault Control
BLDC control with BEMF Zero Crossing using ADC
Section
7.2. The general overview of the software states is in the
Section
Section 1
7.3.2.
Figure
7-5). The DriveFaultStatus is
Software Design
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