DG-IRMCK203 Datasheet, PDF (26/67 Pages) International Rectifier – Application Developer’s Guide

IRMCK203 Application Developer’s Guide
during parking. This time duration is the optimal parking time and should be converted to digital drive units and
entered into register ParkTm. The full scale of ParkTm is 255, which represents 4 seconds.
After the parking diagnostic has been accomplished, please enter these two parameters (ParkI and ParkTm) into the
Sensorless Ctrl Start-up subfunction inside the Configure Motor function, as shown in Figure 13.
Note: To resume normal mode operation (out of diagnostic), the Configure Motor function must be executed again.
Figure 13. Enter Optimal Parking Parameters
Start-up Diagnostic
This diagnostic mode is provided to fine tune open-loop start-up performance. During open-loop start-up, the
IRMCK203 control IC estimates the rotor angle based on a simple motor load model, which uses only one
configurable parameter (KTorque). The user parameter translator (Excel spreadsheet) also generates this parameter
based on user input load inertia. Use this value as a starting point for fine tuning. The goal of this start-up
diagnostic is to fine tune this parameter (KTorque) for optimal open-loop drive control performance. If a correct
value of KTorque is used the drive will produce the highest torque per ampere ratio during open-loop start-up. The
drive may fail to start if excessive error is present in KTorque gain.
When the Start-up Diagnostic function is executed, the drive will enter parking mode followed by open-loop start-up.
The drive will coast to a stop as soon as open-loop is accomplished (determined when motor frequency exceeds the
level prescribed by write register WeThr). If an optimal value of KTorque is used, the drive will accelerate the
motor to a higher speed since maximum torque per ampere is achieved.
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