DIAGNOSTICS FOR SYSTEMS INCLUDING VARIABLE FREQUENCY MOTOR DRIVES

摘要

One embodiment is a diagnostic method for a system including setting a first diagnostic code based upon a condition of a DC bus of a variable frequency drive during a first drive state, setting at least one additional diagnostic code based upon a condition of at least one motor phase current during a second drive state, outputting first diagnostic information indicating a malfunction of the variable frequency drive if the first diagnostic code indicates a first error, and outputting second diagnostic information indicating a malfunction of a motor or a connector coupling the motor and the drive if the at least one additional diagnostic code indicates a second error.

主权项

1. A diagnostic method for a system comprising a variable frequency drive, a motor structured to drive a mechanical load, a connector electrically coupling the variable frequency drive and the motor, and a controller structured to control operation of the variable frequency drive, the variable frequency drive including an inrush relay and a power factor correction (PFC) circuit operatively coupled with a DC bus and an inverter operatively coupled with the DC bus and the motor, the method comprising:
performing a first procedure with the controller including first evaluating a voltage of the DC bus after closing the inrush relay and activating the PFC circuit and setting a value of a first diagnostic code based upon the first evaluating; performing a second procedure with the controller including sequentially turning on each one of a plurality of switches of the inverter while concurrently turning off each other switch of the inverter; performing a third procedure with the controller including injecting a current to one of the plurality of switches of the inverter which is turned on, second evaluating a current of at least one phase of the motor, and setting a value of at least one additional diagnostic code based upon the second evaluating; outputting first diagnostic information indicating a malfunction of the variable frequency drive if the value of a first diagnostic code indicates an error; and outputting second diagnostic information indicating a malfunction of the motor or the connector if the value of the at least one additional diagnostic code indicates an error.