AN1931D Freescale Semiconductor / Motorola, AN1931D Datasheet - Page 46

• Manufacturer Part Number: AN1931D
• Description: 3-Phase PM Synchronous Motor Vector Control
• Manufacturer: Freescale Semiconductor / Motorola

MOTOROLA
6.3.5 Analog Sensing State Diagram
7.
7.1 Scaling of Quantities
Application Control: Begin Init
Application Control: Begin Init
The state diagram of the Analog Sensing subprocess is shown in
state initializes hardware modules like ADC, synchronization with PWM, etc. In Begin Init,
Initialization is started, so the variables for initialization sum and the InitDoneFlag are cleared. In the
Init Proceed state, the temperature, DCBus voltage and phase current samples are sensed and summed.
After required analog sensing, Init samples are sensed, and the Init Finished state is entered. There, the
samples’ average is calculated, from the sum divided by the number of analog sensing Init samples.
According to the phase currents’ average value, the phase current offsets are initialized.
All variable sensing is initialized and the state Init Done is entered, so the variables from analog
sensing are valid for other processes. In this state, temperature and DCBus voltage are filtered in first
order filters.
The PM synchronous motor vector 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
Implementation Notes
-15
, and the most positive long-word is $7FFFFFFF or 1.0 - 2
clear InitDoneFlag
Figure 6-12. State Diagram - Analog Sensing
Analog Sensing:
Analog Sensing
DSP Initialization
normal operation:
Analog Sensing
clear variables
Freescale Semiconductor, Inc.
3-Phase PM Synchronous Motor Vector Control
Begin Init
Init Done,
For More Information On This Product,
Reset
–
1.0
Go to: www.freescale.com
SF +1.0 -2
done
done
–
sense and sum samples
N 1
–
Analog Sensing
count samples
Init. Proceed:
set current offsets
Analog Sensing
samples average
set InitDoneFlag
Init Finished:
Figure
-31
.
6-12. The DSP Initialization
samples counter =
analog sensing init samples
Implementation Notes
(EQ 7-1.)
46