Omron SMARTSTEP 2 R88M-G Series - 4-4 Regenerative Energy Absorption; Calculating the Regenerative Energy

4-35
4-4 Regenerative Energy Absorption
4
System Design
4-4 Regenerative Energy Absorption
The Servo Drives have internal regenerative energy absorption circuitry, which absorbs the
regenerative energy produced during Servomotor deceleration and prevents the DC voltage from
increasing. An overvoltage error occurs, however, if the amount of regenerative energy from the
Servomotor is too large. In this case, measures must be taken to reduce the regenerative energy
by changing operating patterns, or to increase the regenerative energy absorption capacity by
connecting an External Regeneration Resistor.
Calculating the Regenerative Energy
 Horizontal Axis
Note In the output torque graph, acceleration in the positive direction is shown as positive, and
acceleration in the negative direction is shown as negative.
 The regenerative energy values for each region can be derived from the following equations.
Note Due to the loss of winding resistance and PWM, the actual regenerative energy will be
approximately 90% of the values derived from these equations.
 Average regeneration power (Pr): Regeneration power produced in one cycle of operation.
Servomotor
operation
Servomotor
output torque
+N
1
−N2
TD1
TD2
t1 t2
T
E
g1g1Eg1
Eg2g2
Eg2
11
1
2
2
1
t
1TNE
D
g
=
60
****
[J] =0.0524 N1 TD1 t1 [J]
** *
22
2
2
2
1
t
2TNE
D
g
=
60
****
[J] =0.0524 N2 TD2 t2 [J]
** *
N1, N2: Rotation speed at beginning of deceleration [r/min]
T
D1, TD2: Deceleration torque [N·m]
t
1, t2: Deceleration time [s]
Pr = (Eg1 + Eg2) / T [W]
T: Operation cycle [s]