Hitachi SJ Series User Manual page 313

Chapter 12
12.13.4 Controlling output to avoid
overvoltage
Q
• Overvoltage error is generated when the motor is
decelerated.
• I want to decelerate the motor by automatically
increasing the output voltage according to the
regenerative energy during deceleration.
• I want to prevent overvoltage error by increasing
the output voltage when regenerative load is
applied.
A
• [bA146] overexcitation function selection allows
you to enable the overexcitation function.
Parameters
Item
Overexcitation function
selection
Overexcitation output
filter time constant
Overexcitation voltage
gain
Overexcitation
suppression level
Parameter
[bA146]
[bA147] 0.00~1.00(s)
[bA148] 50~400(%)
200 V class: 330.0 - 400.0
[bA149]
400 V class: 660.0 - 800.0
12-13-6
!
• When this function is enabled, the current may
increase as the output voltage increases.
• When using this function, the motor will be
overexcited and the heat generated by the motor
may increase.
• Depending on the deceleration rate or load status,
the overvoltage tripping may be triggered even if
this function is enabled.
• The overexcitation function is activated when
controlling VC characteristics of V/f control, VP
characteristics, and free V/f control.
• The overexcitation function increases the motor
loss and reduces energy to be regenerated in order
to suppress the overvoltage and prevent tripping.
Data
00 Disabled
01 Always active
02 Active only during deceleration
03 Level operation
04 Level operation during deceleration
Filter time constant applied to the
overexcitation output.
Gain for the overexcitation output voltage.
(V) The level at which the overexcitation function
starts its operation.
(V)
Inverter Function
Description