Hitachi SJ700D-004L, Instruction Manual

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Chapter 4 Explanation of Functions
4-41
4.2.32 Over voltage supression
The over voltage supression function allows you to prevent the inverter from
tripping because of the overvoltage that can be caused by the energy
regenerated by the motor during deceleration.
You can enable or disable the function by setting the overvoltage suppression
enable (b130).
When "01" (enabling the over voltage supression [with deceleration stop]) is specified for the overvoltage suppression
enable (b130), the inverter will decelerate by keeping the voltage of the main circuit DC section at over voltage
suppression level (b131).
When "02" (enabling the overvoltage suppression [with acceleration]) is specified for the overvoltage suppression
enable (b130), the inverter will start acceleration according to the acceleration and deceleration rate at overvoltage
suppression (b132) if the voltage of the main circuit DC section exceeds the overvoltage suppression level (b131).
Subsequently, the inverter will restart deceleration when the voltage falls below the level (b131).
Item Function code Data or range of data Description
Overvoltage suppression
enable
b130
00 Disable
01
Enabling the overvoltage suppression (with
controlled deceleration) (See Example 1.) (note5)
02
Enabling the overvoltage suppression (with
acceleration) (See Example 2.) (note6)
03
Enabling the overvoltage suppression (with
acceleration and constant speed) (See Example 2.)
Overvoltage suppression
level (See Note 4.)
b131
330 to 390 (V) Level setting for 200 V class models
660 to 780 (V) Level setting for 400 V class models
Acceleration rate at
overvoltage suppression
b132 0.10 to 30.00 (s)
Specifying the acceleration rate to be applied when
the function is enabled
Overvoltage suppression
propotional gain
b134 0 to 255
Overvoltage suppression propotional gain setting
(valid when b130=01)
Overvoltage suppression
integral time
b135 0 to 65535
Overvoltage suppression integral time setting (valid
when b130=01)
(Example 1) When "b130" is "01": (Example 2) When "b130" is "02" and "03":
Note 1:When this function is enabled, the actual deceleration time may be prolonged over the set time “F003” because of the regenerated electric power.
Note 2:This overvoltage restraint function does not maintain the DC voltage at a constant level. Therefore, inverter trips due to overvoltage may be caused by the setting
of the deceleration rate or by a specific load condition.
Note 3:When this function is enabled, the inverter may requires a long time to decelerate and stop the motor if the load on the motor or the moment of inertia on the
motor is under a specific condition.
Note 4:When a voltage lower than the value (input voltage x √2 x 1.1) is specified for b131, the motor cannot be stopped because the inverter detects high voltage
condition. You should cut the power supply off or activate the free-run-stop function to cut the output to drive the motor.
Note 5:When "01" is specified for b130, PI control is performed so that internal DC voltage is maintained at a constant level.
- Setting a higher proportional gain (b133) results in a faster response. However, an excessively high proportional gain causes control to diverge and results in the
inverter easily tripping.
- Setting a shorter integral time (b134) results in a faster response. However, an excessively short integral time results in the inverter easily tripping.
Note 6:When "02" or “03” is specified for b130, acceleration control is performed.
- When the decelaration time is short, the motor cannot be stopped because the inverter detects high voltage condition intermittently . You should set the longer time
to F003 or you should cut the power supply off or activate the free-run-stop function to cut the output to drive the motor.
- When this function is activated, it occurs that the motor speed stays in the high speed range, for example maximum frequency, or the motor takes too long to
decelerate because of the regenerated electric power. Please check the drive at the test run. You should cut the power supply off or activate the free-run-stop
function to cut the output to drive the motor.
b130: Overvoltage suppression enable
b131: Overvoltage suppression level
b132: Acceleration and deceleration rate
at overvoltage suppression
Related code
*)Acceleration according to
the setting of "b132"
*
F003
b130=02
b130=03
Upper limit
(Maximum
frequency
A004)
*
*
Voltage of the main circuit
DC section (V)
Overvoltage
suppression
level (b131)
Output frequency
(Hz)
Start of
deceleration
Stop of
deceleration
Restart of
deceleration
Stop of
deceleration
Time (s)
Time (s)
F003
Voltage of the main circuit
DC section (V)
Overvoltage
suppression
level (b131)
Time (s)
Time (s)
Start of
deceleration
Constant
speed