7 tuning the current loop – ElmoMC SimplIQ Servo Drives Composer User Manual User Manual

Page 24

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2.7

Tuning the Current Loop

The Composer Wizard begins the tuning process with the current loop because the
current controller must be properly tuned before any other process can be successfully
carried out. When you select Step 1, Tuning Current Loop from the Custom dialog box, a
Tuning Current Loop dialog box similar to the following is displayed.

This step energizes the motor winding with a high-frequency current, in order to identify
the dynamic response for resistance and inductance. The result of the test is a set of well-
tuned current controller parameters. The controller performance is verified by a test
graph showing the Reference, Response and Controller Out vectors. The controller
output is proportional to the motor voltage and is shown in order to verify that during
the test, the motor voltage did not saturate. If the motor voltage does saturate (is clipped
at the top), the response displayed will not reflect the dynamics of the current control
loop but rather the dI/dT limits of the power supply and inductance. In such a case, use
lower Continuous Current levels (defined in the System Definitions and Limits dialog
box,

section

) and repeat the current tuning process from the beginning.

To tune the current loop:

1. Click Run in the dialog box. The current will flow into the motor A phase and divide

equally between the B and C phases. The motor current generates a fixed magnetic field,
so that the motor will jump in the direction of the magnetic field and remain there.

Be aware that the motor shaft may move while the current loop is being
tuned, up to half an electrical rotation at most. Therefore, take the
necessary precautions for the unlikely event of an undesired movement.

Upon completing the test, the system will store the current tuning information and
display the following message:

2. Click Yes to continue directly to the next tuning step.

Composer User Manual

Using the Wizard

MAN-COMPUM (Ver. 1.9)

2-16

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