Regenerative Energy Absorption; Calculating The Regenerative Energy - Omron OMNUC G5 R88M-K series User Manual

4-4 Regenerative Energy Absorption

The Servo Drives have internal regeneration process circuitry, which absorbs the regenerative
energy produced during motor deceleration and prevents the DC voltage from increasing. An
overvoltage error occurs, however, if the amount of regenerative energy from the motor is too
large. If this occurs, remedies must be taken to reduce the regenerative energy by changing
operating patterns, or to increase the regeneration process capacity by connecting an External
Regeneration Unit.

Calculating the Regenerative Energy

Horizontal Axis
Motor operation
Motor output torque
 In the output torque graph, acceleration in the forward direction is shown as positive, and
acceleration in the reverse direction is shown as negative.
 The regenerative energy values in each region can be derived from the following equations.
N , N
1
T , T
D1
t , t
1 2
Note. Due to the loss of motor winding resistance and PWM, the actual regenerative energy will be
approx. 90% of the values derived from these equations.
 For
Servo Drive
models of 400 W or less), the values for both Eg
regeneration absorption capacity. (The capacity depends on the model.For details, refer to the next
section.)
 For Servo Drive
models of 500 W or more), the average amount of regeneration Pr (unit: W) must be calculated, and this value must be
lower than the drive's regeneration absorption capacity. (The capacity depends on the model.For details, refer to the next
section.)
The average regeneration power (Pr) is the regeneration power produced in 1 cycle of operation [W].
=
P
r
T: Operation cycle [s]
OMNUC G5-Series AC Servo Drives Users Manual (Built-in MECHATROLINK-II communications type)
+N
1
T
D1
E E
g1 g1
t
1
: Rotation speed at start of deceleration [r/min]
2
: Deceleration torque
D2
: Deceleration time
models with internal capacitors used for absorbing regenerative energy (i.e., Servo Drive
models with an Internal Regeneration Resistor used for absorbing regenerative energy (i.e., Servo Drive
( E + E ) / T[W]
g 1 g 2

4-4 Regenerative Energy Absorption

−N
2
T
D2
E E
g2 g2
t
2
T
[N·m]
[s]
or Eg (unit: J) must be lower than the drive's
1 2
4
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