AN1917D Freescale Semiconductor / Motorola, AN1917D Datasheet - Page 18

• Manufacturer Part Number: AN1917D
• Description: 3-Phase PM Synchronous Motor Control with Quadrature Encoder Using DSP56F80x
• Manufacturer: Freescale Semiconductor / Motorola

18
Implementation Notes
5.2.3 Drive State Machine
6.
6.1 Scaling of Quantities
The drive can be in any of the states shown in
between the drive states. The user is able to recognize the current state, by a blinking green LED diode.
In the case of the init and stop state, the green LED diode blinks at a frequency of 2 Hz. In the fault
state, the green LED diode blinks at a frequency of 8 Hz. During the running state, the green LED
diode is continuously turned on.
The PM Synchronous motor control application uses a fractional representation for all real quantities
except time. The N-bit signed fractional format is represented using 1.[N-1] format (1 sign bit, N-1
fractional bits). Signed fractional numbers (SF) lie in the following range:
For words and long-word signed fractions, the most negative number that can be represented is -1.0,
whose internal representation is $8000 and $80000000, respectively. The most positive word is $7FFF
or 1.0 - 2
The following equation shows the relationship between real and fractional representations:
Implementation Notes
-15
Stopped
, and the most positive long-word is $7FFFFFFF or 1.0 - 2
State
Figure 5-3. Drive State Machine Transitions
3-Phase PMSM Control with Quadrature Encoder
Freescale Semiconductor, Inc.
Fractional Value
SwitchState=RUN
For More Information On This Product,
SwitchState=STOP
SwitchState=RUN
–
1.0
SwitchState=STOP
Go to: www.freescale.com
SF +1.0 -2
=
------------------------------------------------- -
Real Quantity Range
State
Reset
Init
Real Value
–
u_dc_bus<MIN_DC_BUS_VOLTAGE
Figure
N 1
–
5-3, which shows the transition conditions
Running
State
u_dc_bus>=MIN_DC_BUS_VOLTAGE
-31
.
State
Fault
MOTOROLA
(EQ 6-1.)
(EQ 6-2.)