Toshiba Tosvert VF-S15 Instruction Manual page 189

● The drooping control function is to operate the power-running motor at operating frequency f
lower than command frequency f
the figure above.)
 The droop frequency Δf can be calculated using the following expression.
Droop frequency Δf (Hz)=base frequency vl × f320× (Torque current T
 When the torque current is above the specified droop insensitive torque band (f323), the frequency is
reduced during power running or increased during regenerative braking. The figure above shows an
example of the operating frequency during power running. During regenerative braking, control is
performed to increase the frequency.
 The drooping control function is activated above the torque current set with f323.
 The amount of droop frequency Δf varies depending on the amount of torque current T
Note: If the base frequency vl exceeds 100Hz, count it as 100Hz.
Control is exercised between the starting frequency (f240) and the maximum frequency (fh).
[An example of calculation]
Parameter setting: Base frequency vl=60 (Hz), droop gain f320=10 (%)
Droop insensitive torque band f323=30 (%)
Droop frequency Δf (Hz) and operating frequency f
current T is 100 (%) are as follows;
1
Droop frequency Δf (Hz)=vl × f320 × (T
=60 (Hz) × 10 (%) × (100 (%) - 30 (%))
=4.2 (Hz)
Operation frequency f (Hz) = f
1
(Hz) by droop frequency Δf (Hz), when the torque current is T
0
when command frequency f
1
- f323)
1
- Δf = 50 (Hz) - 4.2 (Hz)=45.8 (Hz)
0
F-77
E6582175
Power running
(Hz), which is
1
(%). (See
1
- f323)
1
.
1
is 50 (Hz) and torque
0
6