Kollmorgen AKD PDMM series, User Manual

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AKD PDMM User Guide | 6.2 Regeneration
6.2 Regeneration
6.2.1 Overview
Regeneration, or "shunting", dissipates energy from the DC bus during deceleration of the motor load. Dur-
ing deceleration, the motor acts as a generator that pumps energy back into the system. If this energy is
not dissipated, then the bus energy level can exceed acceptable levels (VBUS.OVFTHRESH (pg 445)). If
the system exceeds the maximum bus voltage, then the drive generates an over voltage fault (F501) and
shuts down. A regeneration resistor, or regen resistor, is an external device that dissipates excess energy
and allows the drive to function normally during deceleration.
Follow these steps to determine the regen needs for your system and to configure the drive for regen:
1. Calculate motor peak and continuous regenerative energy and use this value to size the regen
resistor.
2. Select a compatible regen resistor.
3. Configure regen parameter values in EWV
1
.
6.2.2 Regen Resistor Options
In the Power screen, you can select from a variety of pre-sized regen resistors using the Regen Resistor
Type box.
When you select -1-External Regen, the Select resistor box appears and contains the pre-sized resistors
for your drive. Select the model regen resistor that you are using and the drive will populate the remainder
of the fields. If you are using a nonstandard resistor, then choose
<User defined> and fill in the appro-
priate values for your resistor.
If you use a nonstandard resistor, contact Kollmorgen™ technical support to confirm
that the nonstandard resistor will work correctly with your system.
6.2.3 Calculating Motor Peak Energy and Regen Resistor Size
In order to determine whether or not your system requires a regen resistor, you must calculate the peak
kinetic energy that the motor generates during deceleration and the continuous regeneration energy
created by the motor. If this energy exceeds the drive capacity, then you need a regen resistor. In many
cases, peak or continuous regenerated energy does not exceed the drive capacity and no regen resistor is
needed.
The calculation for peak kinetic energy requires values for several factors that affect the generation of
energy in a motion system:
l
Load inertia
l
Motor inertia
l
Motor speed from which deceleration occurs
l
Time required to decelerate
1
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36 Kollmorgen™ | December 2012