Hitachi SJ Series User Manual page 311

Chapter 12
12.13.3 Controlling frequency to avoid
overvoltage
Q
• Overvoltage error is generated when the motor is
decelerated.
• I want to decelerate the motor by automatically
extending the deceleration time.
• I want to prevent overvoltage error by increasing
the frequency when
regenerative load is applied.
A
• [bA140] overvoltage suppression function selection
allows you to enable the overvoltage suppression
function.
• The overvoltage suppression function will be
activated when the internal DC voltage of the
inverter main circuit capacitor exceeds the value
set by [bA141] overvoltage suppression level.
Parameters
Item
Overvoltage
suppression function
Overvoltage
suppression level
setting
Overvoltage
suppression operating
time
Constant DC voltage
control Proportional (P)
gain
Constant DC voltage
control Integral (I) gain
Parameter Data
[bA140]
200 V class: 330.0 - 400.0
[bA141]
400 V class: 660.0 - 800.0
[bA142] 0.00~3600.00(s)
[bA144] 0.00~5.00
[bA145] 0.00~150.00
12-13-4
!
• When this function is enabled, the actual
deceleration time may get longer than the set
value.
• When using this function, it may take long time
before the motor stops depending on the motor
load moment of inertia.
• Depending on the deceleration rate or load status,
the overvoltage tripping may be triggered even if
this function is enabled.
• Set [bA141] to be receiving voltage x √2 × 1.1 or
higher. Setting a value lower than the P-N voltage
in operation may prevent the motor from stopping.
00 Disabled
01 Constant DC voltage-controlled deceleration
Function to avoid overvoltage acceleration (only
02
in deceleration)
03 Function to avoid overvoltage acceleration
(V) Sets the level at which the overvoltage
suppression function starts.
(V)
Acceleration time when the overvoltage
suppression function is activated.
Proportional gain for PI control in constant DC
voltage control.
Integral gain for PI control in constant DC
voltage control.
Inverter Function
Description