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Current/torque controller settings

Current controller optimization

The torque controller is executed as a PI controller. The gain (P-component) and the integral-action time (I-component) of the individual controllers are programmable.
In order to optimize the current control loop, two rectangular reference steps are preset. The object of the optimization is a current controller with moderate dynamism and the following values:

• Current control time: = 1 ms
• Overshoot: < 5%
  
  

Bild: Optimization of speed control

Vorgehensweise: Current controller optimization

The faster the actual value approaches the setpoint (reference), the more dynamic is the controller setting. During settling, the overshoot of the actual value should be no more than 5-10% of the reference (guide value).

• The first step (stage 1, time 1) moves the rotor to a defined position.
• The second step (stage 2, time 2) is used to optimize the torque control (step response). The level of the second step should not be selected too large, to prevent the voltage reference from going to the limit (small signal response required).
• The current and time settings automatically adjust to the motor data. The current corresponds to:
  

• ISDSH and ENPO (hardware enable) must be set to "High".
  
• Click "Start test signal" button
• Observe the safety notice: When you confirm the safety notice a step response is executed.
• The oscilloscope is set automatically.
  
  
  

Bild: Current controller optimization

Creating the transfer function

The oscilloscope automatically records the amount and phase response of the controller according to the controller settings. This produces an initial estimate of the control quality.

To determine the transfer function the noise amplitude (motor rated current) and the sampling time (default 0.125 ms) must be specified. Click the "Start Test Signal" button.

Bild: Noise amplitude, sampling time

Bild: Current controller transfer function

	Green curve = Amount Y-axis left = Absolute value of isd/isdref
	Blue curve = Phase response Y-axis right = Phase response Isd / isdref