ATAVRMC300 Atmel, ATAVRMC300 Datasheet - Page 13

• Manufacturer Part Number: ATAVRMC300
• Description: BOARD EVAL LV MOTOR CONTROL PWR
• Manufacturer: Atmel
• Series: AVR®r

Specifications of ATAVRMC300

• Main Purpose: Power Management, Motor Control
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: ATmega32M1
• Primary Attributes: 3-Ph BLDC, Brushed DC, Stepper Motor Driver Board, 40V, 6A
• Secondary Attributes: Requires ATAVRMC301, ATAVRMC303, or ATAVRMC310
• Processor To Be Evaluated: ATmega32M1
• Data Bus Width: 8 bit
• Interface Type: RS-232, USB
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

5.3
8138A–AVR–04/08
CPU & Memory Usage
Figure 11. Ki tuning example
In
To adjust the KD parameter:
•
•
Another significant point is the sampling time. It has to be chosen according to the response time
of the system. The sampling time must be at least twice as small as the response time of the
system (according to the Shannon-Nyquist criteria).
Two functions are available for the sampling time configuration (explained previously). They
result in a global variable called g_tick which is set every 250us. With this variable it is possible
to configure the sampling time.
All measurements have been realized with Fosc = 16MHz. They also depend on the motor type
(numbers of pair of poles). With a motor of 4 pairs of poles, hall sensor frequency is four times
faster than the motor rotation.
All results in
and a maximum speed of 6900 rpm. (Motor provided with the ATAVRMC300 kit)
Table 5-1.
In the worst case, the microcontroller utilization ratio is about 3.5% with a sampling time of 80ms
at 6900 rpm.
m c_s witch_com m utation() Speed = 6900 rpm
Figure 10
m c_es tim ation_s peed()
If the reponse is still slow, increase KD gain.
If the reponse is still unstable, decrease KD gain.
m c_regulation_loop()
250
200
150
100
50
0
Function
and
Figure 5-1
Microcontroller utilization rate
Figure
11, the right parameters are KP = 1, KI = 0.5 and KD = 0.
are obtained with a three phases BLDC motor with four pairs of poles
Speed = 6900 rpm
Time (s)
Param eters
Clos e Loop
Open Loop
activation tim e
1.4 us
15 us
20 us
8 us
Reference Speed
Ki=1 ; Kp=1
Ki=2 ; Kp=1
Ki=0,5 ; Kp=1
Speed Consign
activation period
300 us
80 m s
80 m s
2 m s
AVR194
Ratio uc %
0.0175
0.025
0.75
2.7
13