DG-IRMCK203 Datasheet, PDF (29/67 Pages) International Rectifier – Application Developer’s Guide

IRMCK203 Application Developer’s Guide
During motor parking (first stage of motor startup), a certain amount of dc current is injected into the motor windings
for the purpose of initialization of rotor position. If motor feedback currents do not match the expected dc injection
current level, a phase loss fault (PhsLossFlt) is triggered. This fault can be disabled via bit 4 (PhsLosFltDisable field)
of the MtrCtrlBits write register.
Start-up Retrial
This function provides start-up retrials upon a start-up failure. Start-up failure may occur if the motor shaft is jammed
or motor starting torque cannot overcome shaft friction during startup.
Motor starting torque can be controlled by motor starting current limit (StartLim) as shown in Figure 18. The scaling
of StartLim is 4095 = rated motor current.
The write registers written on execution of the Startup Retrial function are described below. The function is shown
in
Figure 19.
NumRetries – This parameter determines the number of start-up retries. A value of zero will disable startup retry. The
maximum number of retries is 15.
FlxThrL - The low flux threshold level for determining a successful startup (scaling: 129 = 100% flux). Please do not
modify this parameter without consulting a motor drive FAE.
FlxThrH - The upper flux threshold level for determining a successful startup (scaling: 64 = 100% flux). Please do
not modify this parameter without consulting a motor drive FAE.
This document is the property of International Rectifier and may not be copied or distributed without expressed consent.
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