Parameter
structure
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Parameter
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Parameter
description format
Advanced parameter
descriptions
Macros
Serial comms
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Electronic
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Menu 5
Unidrive SP Advanced User Guide 125
Issue Number: 10 www.controltechniques.com
This parameter defines the required switching frequency. The drive may automatically reduce the actual switching frequency (without changing this
parameter) if the power stage becomes too hot. The switching frequency can reduce from 12kHz to 6kHz to 3kHz, or 16kHz to 8kHz to 4kHz. An
estimate of the IGBT junction temperature is made based on the heatsink temperature and an instantaneous temperature drop using the drive output
current and switching frequency. The estimated IGBT junction temperature is displayed in Pr 7.34. If the temperature exceeds 135°C the switching
frequency is reduced if this is possible (i.e >4kHz) and this mode is enabled (see Pr 5.35 on page 131). Reducing the switching frequency reduces the
drive losses and the junction temperature displayed in Pr 7.34 also reduces. If the load condition persists the junction temperature may continue to
rise. If the temperature exceeds 145°C and the switching frequency cannot be reduced the drive will initiate an O.ht1 trip. Every 20ms the drive will
attempt to restore the switching frequency if the higher switching frequency will not take the IGBT temperature above 135°C.
The following table gives the sampling rate for different sections of the control system for different switching frequencies.
200V kHz 400V kHz 575V kHz 690V kHz
SP0201 16 SP0401 16 SP3501 8 SP4601 8
SP0202 16 SP0402 16 SP3502 8 SP4602 8
SP0203 16 SP0403 16 SP3503 8 SP4603 8
SP0204 16 SP0404 16 SP3504 8 SP4604 8
SP0205 16 SP0405 16 SP3505 8 SP4605 8
SP1201 16 SP1401 16 SP3506 8 SP4606 8
SP1202 16 SP1402 16 SP3507 8 SP5601 8
SP1203 16 SP1403 16 SP5602 8
SP1204 16 SP1404 16 SP6601 6
SP2201 16 SP1405 16 SP6602 6
SP2202 16 SP1406 16 SPMA1601 6
SP2203 16 SP2401 16 SPMA1602 6
SP3201 12 SP2402 16 SPMD1601 6
SP3202 12 SP2403 16 SPMD1602 6
SP4201 8 SP2404 16 SPMD1603 6
SP4202 8 SP3401 16 SPMD1604 6
SP4203 8 SP3402 16
SP5201 8 SP3403 12
SP5202 8 SP4401 8
SPMD1201 6 SP4402 8
SPMD1202 6 SP4403 8
SPMD1203 6 SP5401 8
SPMD1204 6 SP5402 8
SP6401 6
SP6402 6
SPMA1401 6
SPMA1402 6
SPMD1401 6
SPMD1402 6
SPMD1403 6
SPMD1404 6
3, 6, 12kHz 4, 8, 16kHz Open-loop
Closed-loop
vector
Servo Regen
Level 1
3 = 167μs
6 = 83μs
12 = 83μs
125μs Peak limit Current controllers
Level 2 250μs
Current limit
and ramps
Speed controller and ramps
Sequencing and
Synchronization
Level 3 1ms Voltage controller
Level 4 4ms Time critical user interface
Background N/A Non-time critical user interface
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