User`s manual

SECTION 5: DS2100 FUNCTIONAL OVERVIEW DS2100 User's Manual
C27750-001 Page 5-9 -
5.3.5 Regeneration Control
Rapid motor deceleration or an overhauling load creates a situation in which energy is returned back into the D.C.
Bus. The regeneration energy will charge up the power supply bus capacitors, causing their voltage to increase. To
prevent capacitor over voltage, a shunt regulator circuit senses when the bus voltage exceeds the Regeneration cut-in
voltage and switches a Regeneration resistor across the D.C..Bus, (via a Regeneration transistor) to dissipate the
Regeneration energy.
The Regeneration resistor is protected by software to limit the power delivered to the internal or external
Regeneration resistors. As the DS2100 uses only one Regeneration transistor, both the internal and external
Regeneration resistors are effectively connected in parallel. Thus, the software will limit the duty cycle of the
transistor to protect the component with the lower power ratings.
The Regeneration resistor control software allows the use to enter data for both the internal and external
regeneration resistors separately. The software then calculates the appropriate duty cycle for the regeneration
transistor. The available and actual regeneration powers are available to the user. If the regeneration power is greater
than 90% of the available regeneration power, the drive will display a Regeneration Power Warning (U4) on the 7-
segment display to indicate to the user that the drive is close to its maximum regeneration capability.
The Regeneration control can operate in one of five modes:
1. Regeneration Off:- In this mode, the regeneration transistor is not switched on and therefore the supply
must have the capability to absorb the regeneration power so that the bus voltage does not rise above the
upper limit.
2. Duty cycle controlled:- In this mode, the duty cycle calculated from the regeneration resistor data is used to
detemine the off times for the regeneration transistor from the on time parameters. The initial on time is
used from the first regeneration event until the initial on time has been consumed. After, this the continuous
on time is used to determine the regeneration off time. If regeneration is off for sufficient time to allow the
initial off time to run out, then the initial on time is used for the next regeneration event.
3. Duty cycle controlled + power fault:- In this mode, the regeneration duty cycle is controlled in the same
way as above, but a fault is detected if the average power exceeds the maximum power for the regeneration
resistor(s). This fault (regen max power exceeded) will cause the drive to disable and transition to a fault
mode.
4. Power fault only:- In this mode, the regeneration duty cycle is not controlled. The regeneration transistor is
switched on when the bus voltage rises above the regeneration turn-on voltage and is switched off when the
bus voltage falls below the turn-off voltage. The regeneration resistor is only protected by the fault
detection of the average power exceeding the maximum regeneration power.
5. Power warning only:- In this mode, the regeneration duty cycle is not controlled and the regeneration
resistor is not protected by the drive at all. The regeneration transistor is switched on and off as in the
‘power fault only’ mode above, but the fault detection is disabled. Only the regeneration power warning is
available to indicate that the regeneration is approaching its maximum capability.