Lenze i700

5 Motor control & motor settings
5.13 Parameterising filter elements in the setpoint path
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Lenze · i700 servo inverter · reference manual · DMS 3.0 EN · 06/2016 · TD06
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[5-10] Use of the notch filter depending on the resonant frequency
• The notch filters are suitable for use with resonant frequencies equal to or higher than the limit
frequency of the speed controller.
• Resonant frequencies ≥ f
limit_speed_controller
= 70 Hz ... 110 Hz
• For resonant frequencies lower than the limit frequency of the speed controller, the use of
suitable speed profiles with an S-shaped ramp is recommended.
Setting the notch filters
Since the exact frequency response of the speed control path in most cases is not known
beforehand, an experimental procedure for setting the notch filters is described in the following.
 How to set the notch filters:
1. Setting and optimising the current controller
.
2. Adapt the speed controller reset time to the filter time constant of the speed filter time and
the equivalent time constant of the current control loop:
• The following applies to axis A: 0x2900:2
= 16 * (0x2904 +500μs)
• The following applies to axis B: 0x3100:2
= 16 * (0x3104 +500μs)
Note: The setting of the reset time includes the equivalent time constant of the current
control loop. The 500 μs indicated are typical in a power range of up to 50 kW. Above this
value, greater time constants may occur.
3. Slowly increase the proportional gain of the speed controller in 0x2900:1
(or 0x3100:1 for
axis B) until the speed control loop starts to be unstable (acoustic determination,
measurement of the motor current or recording of the speed output signal).
4. Measure the oscillation frequency using an oscilloscope:
• Assessing the motor current via 0x2DD1:4
• Assessing the motor speed via 0x6044.
5. Set the oscillation frequency determined as filter frequency in 0x2944:1
(or 0x3144:1 for
axis B).
6. Set the filter width to 40 % of the filter frequency in 0x2944:2
(or 0x3144:40 for axis B).
• Example: Filter frequency = 250 Hz  filter width = 100 Hz.
7. Set the filter depth to 40 dB in 0x2944:3
(or 0x3144:3 for axis B).
• If "0 dB" are set (default setting), the filter is not effective.
 Use of notch filters possible without any interactions
 Use of notch filters only possible with restrictions
 The notch filter should not be used
f
limit_speed_controller
1
2
f
2
f
limit_speed_controller
1 0