8.22 High Performance Control
8.22.1 High Performance Control_Prologue
When applying Perfect Harmony drives, applications requiring high starting torque or low speed
operation are considered as "high performance" control.
8.22.2 Low Speed Operation
In some applications, when stable, low speed operation, below 1 Hz, under high torque
conditions is required, an encoder may be used to provide speed feedback. Use of a shaft
encoder is recommended where the control’s slip calculation block is disabled so that encoder
speed feedback is directly used as an input to the speed regulator. When an encoder is used with
the drive, set the control loop type to closed loop vector control with an induction motor (CLVC)
or to closed loop vector control with a synchronous motor (CSMC). Enable the drive's Spinning
Load function when this control mode is enabled.
8.22.3 High Starting Torque Mode
Special applications and motors require a high starting torque mode. Examples of motors that
require a high starting torque (HST) mode:
• Permanent Magnet Motors (PMM) have a xed ux source from the magnets, and must be
moving in order to lock on to the ux phase.
• Synchronous Motors with a DC exciter (SMDC) cannot be magnetized until the eld aligns
with the poles in the machine.
When starting a PMM or SMDC from standstill, the ux vector cannot be determined until motion
is established. It is necessary to apply an adequate amount of torque current for a short period
of time to overcome the inertia of the rotor and to produce movement. Once movement occurs,
the PLL can lock onto the ux vector.
Advanced Operating Functions
8.22 High Performance Control
NXGPro+ Control Manual
Operating Manual, A5E50491925A 321
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