Toshiba VF-A7 instruction manual Drooping control, Drooping Gain, Dead band Frequency

6.14 Drooping control

 ：Drooping gain

 ：Speed at a drooping gain 0%

 ：Speed at the drooping gain 

 ：Drooping insensitive torque band

 ：Output filter for drooping

Note : Above parameters are valid only when  is set at ,  or .

・Function

When operating a single load with more than one inverter and one motor, these parameters distribute the load to the inverters. These parameters can adjust the frequency range, the insensitive torque band and gains.

Ｇａｉｎ１	Ｇａｉｎ２	Drooping
Drooping		gain
gain	
－ 	
Internal torque reference			
		－ 

Dead band

Dead band

Frequency

[Parameter setting]

Title	Function	Adjustment range	Default setting
	Drooping gain	～ [%]	
	Speed at a drooping gain 0[%]	～ [Hz]	
	Speed at the drooping gain 	～ [Hz]	
	Drooping insensitive torque band	～ [%]	
	Output filter for drooping	～ [rad/s]	

・When torque larger than the dead band torque is applied, the frequency is decreased (during power running) or increased (during regenerative braking).

・Drooping takes effect within the frequency range above the frequency set with .

・In the frequency range between  and , the drooping rate varies with the torque.

The change in the frequency during drooping can be calculated as described below.

a)Gain by internal torque reference (Gain 1) If internal torque reference [%]≧0

Gain1 ＝（internal torque reference－dead band  Grain 1 needs to be set at 0 or a positive number.

If internal torque reference [%]＜0

Gain1 ＝（internal torque reference＋dead band  Grain 1 needs to be set at 0 or a negative number.

）/ 100

）/ 100

b)Gain by frequency after acceleration (Gain 2) If  ＜ 

｜Frequency after acceleration｜≦Frequency 1 set with

Gain2 ＝ 0



｜Frequency after acceleration｜＞Frequency 2 set with

Gain2 ＝ Drooping gain  / 100



F-31