Chapter 4 Explanation of Functions
4-41
4.2.32 Over voltage supression during deceleration
- 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).
Overvoltage suppression
enable
Enabling the overvoltage suppression (with
controlled deceleration) (See example 1.) (note5)
Enabling the overvoltage suppression (with
acceleration) (See example 2.)
Enabling the overvoltage suppression (with
acceleration and constant speed) (See example 2.)
Overvoltage suppression
level (See Note 4.)
Level setting for 200 V class models
Level setting for 400 V class models
Acceleration rate at
overvoltage suppression
Specifying the acceleration rate to be applied when
the function is enabled
Overvoltage suppression
propotional gain
Overvoltage suppression propotional gain setting
(valid when b130=01)
Overvoltage suppression
integral time
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 acceleration time may be prolonged over the set time.
Note particularly that the motor may not be decelerated if the setting of "b131" is too small when "02" is specified for the overvoltage
suppression enable (b130).
Note 2:This overcurrent 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:If a voltage lower than the input voltage is specified for b131, the motor cannot be stopped.
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.
b130: Overvoltage suppression enable
b131: Overvoltage suppression level
b132: Acceleration and deceleration rate
at overvoltage suppression
Voltage of the main circuit
DC section (V)
Overvoltage
suppression
level (b131)
Voltage of the main circuit
DC section (V)
Overvoltage
suppression
level (b131)
Acceleration according
to the setting of "b132"
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