Fuji Electric FRENIC-HVAC User Manual page 391

Dynamic torque vector control

To get the maximal torque out of a motor, this control calculates the motor torque matched to
the load applied and uses it to optimize the voltage and current vector output.
Selecting this control automatically enables the auto torque boost and slip compensation
function so that it is effective for improving the system response to external disturbances such
as load fluctuation, and the motor speed control accuracy.
Note that the inverter may not respond to a rapid load fluctuation since this control is an
open-loop V/f control that does not perform current control, unlike vector control. Other
advantage of this control is that the maximum torque per output current is larger than that of
vector control.
Since slip compensation and dynamic torque vector control use motor parameters,
the following conditions should be satisfied to obtain full control performance.
• A single motor is controlled per inverter.
• Motor parameters P02, P03, P06 to P12 are properly configured. Or, auto-tuning
(P04) is performed.
• Under dynamic torque vector control, the capacity of the motor to be controlled is
two or more ranks lower than that of the inverter. Otherwise, the inverter may not
control the motor due to decrease of the current detection resolution.
• The wiring distance between the inverter and motor is 164 ft (50 m) or less. If it is
longer, the inverter may not control the motor due to leakage current flowing
through stray capacitance to the ground or between wires. Especially, small
capacity inverters whose rated current is also small may be unable to control the
motor correctly even if the wiring is less than 164 ft (50 m). In that case, make the
wiring length as short as possible or use a wire with small stray capacitance (e.g.,
loosely-bundled cable) to minimize the stray capacitance.
6.3 Details of Function Codes
6-81