January 2012 6.19 Configuring the Controller Unit and Drive Motors 1049
The cycle time of the current controller depends on the PWM frequency:
If a control loop is operated at double the fundamental PWM frequency, the
current controller cycle time is halved. However, this is possible only with
double-speed control loops.
If you want to operate single-speed control loops at double the fundamental
PWM frequency,
Set MP_iCtrlPwmType = 1 in order to calculate the current controller cycle
time from the fundamental PWM frequency although the control loop will
be operated at double the fundamental PWM frequency.
If you operate a single-speed control loop at double the fundamental PWM
frequency and half the current controller cycle time (MP_iCtrlPwmType =0),
the error message C017 PWM frequency too high will appear. Current
controller cycle time depending on the PWM frequency:
MP_iCtrlPwmType
Current controller cycle time
Available from NCK software version: 597 110-03.
Format: Numerical value
Input: 0: Cycle time = 1 / (2 · f
PWM
)
1: Cycle time = 1 / f
PWM
2: Reserved
The value from CfgPowerStage/ampPwmFreq is used as the
PWM frequency f
PWM
.
Default: No value, parameter optional
Access: LEVEL3
Reaction: RUN
PWM
frequency
Single-speed control loop Double-speed control loop
MP_iCtrlPwmType MP_iCtrlPwmType
=0 =1 =0 =1
3.333 kHz 150 µs Error C013! 150 µs Error C013!
4 kHz 125 µs Error C013! 125 µs Error C013!
5 kHz 100 µs Error C013! 100 µs Error C013!
6.666 kHz Error C017! 150 µs
a
a. Fundamental PWM frequency of 3333 Hz
75 µs 150 µs
a
8 kHz Error C017! 125 µs
b
b. Fundamental PWM frequency of 4000 Hz
62.5 µs 125 µs
b
10 kHz Error C017! 100 µs
c
c. Fundamental PWM frequency of 5000 Hz
50 µs 100 µs
c
T
I
1
2f
PWM
⋅
-----------------=
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