Hitachi SJ700-2 instruction manual Over voltage supression during deceleration

Related code

b130: Overvoltage suppression enable

b131: Overvoltage suppression level

b132: Acceleration and deceleration rate at overvoltage suppression

Chapter 4 Explanation of Functions

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).

Item	Function code	Data or range of data	Description
		00	Disable
Overvoltage suppression		01	Enabling the overvoltage suppression
	b130		(with controlled deceleration) (See
enable			example 1.) (note5)
		02	Enabling the overvoltage suppression
			(with acceleration) (See example 2.)
Overvoltage suppression	b131	330 to 390 (V)	Level setting for 200 V class models
level (See Note 4.)		660 to 780 (V)	Level setting for 400 V class models
Acceleration rate at	b132	0.10 to 30.00 (s)	Specifying the acceleration rate to be
overvoltage suppression			applied when the function is enabled
Overvoltage suppression	b134	0 to 255	Overvoltage suppression propotional gain
propotional gain			setting (valid when b130=01)
Overvoltage suppression	b135	0 to 65535	Overvoltage suppression integral time
integral time			setting (valid when b130=01)

(Example 1) When "b130" is "01":

Voltage of the main circuit DC section (V)

Overvoltage suppression level (b131)

Output frequency (Hz)

Stop of

deceleration

(Example 2) When "b130" is "02":

Voltage of the main circuit DC section (V)

Overvoltage suppression level (b131)

Time (s)	Output frequency
	(Hz)

Time (s)

Start of

deceleration

Stop of

Start of

deceleration

Restart of

deceleration

deceleration

Acceleration according the setting of "b132"

Time (s)

Time (s)

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.

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