Inverter Fault Diagnosis And Fault-Tolerant Control

Inverter is the most ideal AC drive equipment so far, but it as a power electronicproduct, always has some problems or failures. With the widespread use of inverter,reliability becomes a bottleneck that limits its use. Especially, in some specificcircumstances, it doesn’t allow inverter stop suddenly or long downtime, request itcan continue to run after fault without reducing system performance or reducingsome performance, so as to ensure the reliable operation and get a minimumeconomic losses. Since this paper will classify the inverter faults, and deeply studythe faults that can use fault-tolerant control, such as speed sensor fault(SSF) andIGBT open-circuit fault(IGBT-OCF).If inverter does not take any measures when SSF happened, it will leaduncontrollable of system, damage of equipment, system long downtime and causeshuge economic losses. While, if taking some measures of fault diagnosis and fault-tolerant strategies the accident can be avoided. So this paper made a detailed studyabout the speed sensor fault diagnosis method based on state observer, realizedspeed sensorless vector control(SLVC), came up with the corresponding fault-tolerant control strategies and realized the switchover of system control mode fromvector control(VC) with speed sensor to SLVC on line after SSF happened.About IGBT-OCF, this paper came up with a modified method, showed the threephases four switches inverter fault-tolerant control strategies, gave a detailedderivation procedure of it, came up with a corresponding over modulation strategiesand realized a complete PWM method. So as to realize that inverter can done faultdiagnosis, fault isolation and corresponding fault-tolerant control without stop afterwhen a IGBT-OCF occurred.Aim at these two faults of inverter, this paper will give out diagnosis methods andfault tolerance strategies firstly by theory analysis and simulation, ultimately, thevalidity of these methods will be proved by experiment.