Baldor MicroFlex e100, Руководство по установке

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B-2 Control System MN1942
B.1.1 Servo configuration
The servo configuration is the default configuration for the drive, allowing the motor control
system to operate as a torque controller, a velocity controller or a position controller. This
configuration comprises 3 nested control loops; a current control loop, a velocity control loop and
a position control loop, as shown in Figure 60.
The universal encoder interface reads rotor position from the encoder and estimates velocity.
The commutation block uses the position to calculate the electrical angle of the rotor. The current
sensor system measures U and V phase currents. These are fed into a current conversion block
that converts them into quantities representing torque producing and magnetizing currents (the
’vector’ currents which are locked to the rotor).
In the current control loop, a current demand and the final measured current values form the
inputs to a PI (Proportional, Integral) control system. This control system generates a set of
voltage demands that are fed into a PWM (pulse-width modulation) block. The PWM block uses
the space-vector modulation method to convert these voltage demands into a sequence of U, V
and W phase switching signals, which are applied to the output bridge of the drive. The PWM
block uses the measured DC bus voltage to compensate for variations in supply voltage.
The torque controller converts a torque demand into a current demand and compensates for
various load non-linearities. A 2-stage notch or low-pass filter allows the effects of load
compliance to be reduced. To avoid motor damage, a user-defined application current limit is also
applied, as well as individual positive and negative torque limits.
In the velocity control loop, a velocity demand and measured velocity form the inputs to a PI
control system. The output of the control system is a torque demand which, when the drive is
operating as a velocity controller, forms the input to the current control loop.
Finally, in the position control loop, a position demand and measured position form the inputs to
a PID (Proportional, Integral, Differential) control system incorporating velocity feedback,
velocity feed-forward and acceleration feed-forward. The output of the position control system
is a velocity demand which, when the drive is operating as a position controller, forms the input
to the velocity control loop.