AMD2000 Series - Servo Drive - User Manual
112
DS619-0-00-0019 - Rev 0
ANCA Motion
The general idea of this technique is to inject
d
-axis current and repeatedly sweep the commutation angle
through 360 degrees. The frequency of the commutation angle must be fast enough so that the motor does not
begin tracking the rotating magnet field, but slow enough to ensure acceptable convergence of the algorithm.
Given this, the algorithm consists of the following major components:
1. Stimulus generation: generate
d
-axis current with defined amplitude and frequency;
2. Data acquisition: measure the motor reaction (electrical displacement) as a result of the stimulus;
3. Torque estimation: estimate electrical torque as a function of electrical angle; and
4. Alignment angle offset estimation: estimate the electrical angle offset for optimum torque generation and
efficiency.
Table 10-5
below lists the Acceleration Observer configuration parameters.
Table 10-5 Configuration parameters and default values for Acceleration Observer FOI
IDN
Name
Value
Units
Note
33060
Field Orientation Initialisation
Control
1
0: none
1: once
2: always
33065
Field Orientation Initialisation
Type
4
1: DQ Alignment
2: Preset Offset
3: Absolute
4: Acceleration Observer
33900
Stimulus Amplitude
3000
[mA]
33901
Stimulus Frequency
800000
[10
-4
Hz],
33903
Stimulus Repeat Count
10
33904
Stimulus Time
500
[T1]
33905
Motor Movement Maximum
Deviation
200000
0
[10
-4
mech rev]
33906
Phase Estimator Correction
2
[T1]
33910
Torque Estimator Model Type
0
0: Inertia
1: Compliant
33913
Torque Estimator Model Inertia
99
[kg.mm^2]
33914
Torque Estimator Model
Stiffness
25600
[2
-8
Nm/mech
rev]
Suggestions for selecting key parameters
Torque estimator model type:
o
For unbraked motors:
Use inertia model (IDN 33910 = 0) for estimating torque.
Axis inertia (IDN 33913) does not need to be exact; typically a larger value will ensure
that a suitable torque estimate as a function of stimulus electrical angle is achieved.
o
For braked motors:
Use compliant model (IDN 33910 = 1) for estimating torque.
Axis stiffness (IDN 33914) does not need to be exact; typically a larger value will
ensure that a suitable torque estimate as a function of stimulus electrical angle is
achieved.
Stimulus configuration:
o
Stimulus amplitude (IDN 33900) should be selected using trial and error. Start with a small
value and then gradually increased in small steps. A large amplitude can result in excessive
vibration and mechanical damage.
o
Stimulus frequency (IDN 33901) should be selected using trial and error. Start with a large
value and then gradually reduce in small steps. A small value may result in the motor tracking
the rotating magnet field; resulting in excessive displacement. In short, the stimulus frequency
must be well above the axis position-loop bandwidth.
o
Test time = IDN 32904 x IDN 33903 [250us]. For example, if IDN 32904 = 750 and IDN 33903
= 10, then the test time = 1.875 [sec].
Error messages
E414: Acceleration Observer Torque Response Amplitude Low
