18/05/2001
Autotuning
1
•Why to Use Autotuning
X1
Inverter needs motor equivalent
circuit data for internal
calculations to achieve
maximium motor performance
X2
R2/s
Xh
R1
3 ways of getting the motor equivalent circuit data:
• Ask the manufacturer – Needs time and often the information is poor
• Manually calculation – By using the name plate data the necessary
equivalent circuit data can be calculated but it is
impractical
• Autotuning – only input name plate data, rest is done by inverter
We have now 3 Autotuning modes
Terminal Resistance
Rotating Autotuning
Non Rotating Autotuning
18/05/2001
Autotuning
2
•Terminal Resistance Tuning Mode
NEW tuning mode
Available in all control modes (V/f, V/f w. PG, Vector)
Inverter detects Terminal Resistance
• The Inverter applies a DC voltage to the motor and detects the
resulting current.
• Terminal Resistance can be calculated easily.
• Motor does not rotate while terminal resistance tuning mode.
Result:
• By knowing the resistance the motor internal voltage drop and
motor temperature influence can be compensated.
• When using long motor cables, the voltage drop at the cable
resistance can be compensated by the inverter.
18/05/2001
Autotuning
3
•Rotating Autotuning
Available in Open Loop Vector mode
Inverter determines
•
•
•
•
•
Terminal Resistance,
Leakage Inductance
No Load Current
Core Saturation Coefficient
Rated Slip Frequency
Result:
• By knowing the exact motor equivalent data the inverter can
calculate the Id and Iq values very accurate.
• Maximum speed and tourque accuracy can be achieved.
ONE BIG DISADVANTAGE:
• The motor is rotating while Autotuning
Not usable at applications, where load and motor
can´t get disconnected
18/05/2001
Autotuning
!
4
•Non Rotating Autotuning
NEW tuning mode
Available in Open Loop Vector mode
2 Parts: Non Rotating Part and Test Mode
Non Rotating Part
• Terminal Resistance,
• Leakage Inductance
• The values for No Load Current and Motor Rated Slip are taken from an inverter
internal motor data table (based on Yaskawa standard motors).
Test Mode
• First run of the motor with min. 30% of rated speed. Speed agree must be detected.
• Real values of No Load Current and Rated Slip are detected during test mode.
Result:
• By knowing motor equivalent data Id and Iq can be calculated very accurate.
ADVANTAGE: Motor does not has to rotate while Autotuning
Autotuning now is performable in almost every
case, even if motor and load are coupled
18/05/2001
Autotuning
!
5
• How Non Rotating Autotuning
Works
Motor Speed 360rpm/div
0rpm
Output current 10A/div
I
The inverter applies DC voltage to the motor,
detects the resulting current and calculates
the terminal resistance.
II
First 50% of motor rated currend with 15Hz is
applied to the motor, after that 50% of rated
current with 30 Hz is applied to the motor.
Leakage inductance is detected while this
procedure.
III Step II is repeated with 100% of motor rated
current.
I
II
Output voltage 100V/div
18/05/2001
III
Phase voltages while step II and III:
VU = -½ VW
VV = -½ VW
(phase angle is the same in all 3 phases)
Hence the motor does not rotate.
Autotuning
6
• Tuning Accuracy
Rotating Autotuning accuracy
• Tuning accuracy according to real motor data:
Rated Slip
No Load Current
Terminal Resistance
Leakage Inductance
Core Sat. Coeff.
+/- 10%
+/- 5%
+/- 20%
+/- 20%
+/- 5%
Non Rotating Autotuning accuracy
• Tuning result of rated slip derivates max. +/-20% from rotating tuning result
• No load current value derivates max. +/-10% from rotating tuning result
• Tuning accuracy according to real motor data:
Rated Slip
No Load Current
Terminal Resistance
Leakage Inductance
+/- 12%
+/- 5.5%
+/- 20%
+/- 20%
Requirement for a High Tuning Accuracy
• Motor and inverter capacity may derivate not more than one size
18/05/2001
Autotuning
7
•Summary:
The new Non Rotating Autotuning gives us the opportunity to use Vector
Control with a very high performance even at applications, where an
Autotuning was not possible in the past.
Examples:
• Centrifuges
• Industrial Washing Machines
• Applications with Gear Motors
• Sharer Loaders
• ...
18/05/2001
Autotuning
8
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