Vonsch Quatrofrem Series, Конфигурация и диагностика

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UNIFREM v.3.41x
10 May 2017 Page 138 from 180
value of the maximal regenerative current or generate the RESET command or interrupt the
safety(emergency) input.
Parameters of the controller (P, I and D) influence the speed, the converter can restrict current with
and prevent undesired current increase over allowed limit.
Parameter ID: 353
SETTINGS
– > CONTROL AND REGULATION – > V/f CONTROL -> MAX. CURRENT
CONTROLLER (MCC) -> P component of the MCC [ ]
Parameter ID: 354
SETTINGS
– > CONTROL AND REGULATION – > V/f CONTROL -> MAX. CURRENT
CONTROLLER (MCC) - > I component of the MCC [ms ÷ s]
Parameter ID: 1047
SETTINGS
– > CONTROL AND REGULATION – > V/f CONTROL -> MAX. CURRENT
CONTROLLER (MCC) -> D component of the MCC [ ]
MCC restricts the slope of frequency increase or decrease by ramps, but it can also take up during
steady speed, when the current exceeds configured limits. If the frequency correction reaches
frequency limit Fmin [110] or Fmax [112], it will not longer correct the frequency which will be
affecting the current increase and then "Overcurrent" or "Converter overload" faults are possible.
Fast correction of the starting voltage based on excessive current can be turned on to speed up
the the MCC reaction and to improve operation in the low frequency range.
The gain is adjusted by
following parameter:
Parameter ID: 799
SETTINGS
– > CONTROL AND REGULATION – > V/f CONTROL-> MAX. CURRENT
CONTROLLER (MCC)-> MCC Gain [ ]
This parameter serves to set the voltage and frequency correction of MCC:
Parameter ID: 1191
SETTINGS
– > CONTROL AND REGULATION – > V/f CONTROL -> MAX. CURRENT
CONTROLLER (MCC) -> Freq. boost. MCC [ ]
Scalar (V/f) drive with current limit can be tuned by using these two parameters in order to satisfy
maximal current and to keep the frequency not too low, to prevent torque lose (See. stiffen up the
drive in the previous picture).
Current restriction may cooperate with slip compensation and with compensation of IR in V / f
curve, as well as with other converter functions. There is a category of drives, where it is not
appropriate to use MCC. These are stroke or lift drives of cranes, elevators and conveyors, where
current restricition could result in the weight fall or violation to ramp speed.
Then drive at high
current reports generally a fault.