The invention discloses a method for controlling NPC three-level
inverter fault redundancy. The method for controlling the NPC three-level
inverter fault redundancy comprises the following steps of (1) carrying out fault detection on an NPC three-level
inverter in real time to confirm a fault position and a fault type, (2) confirming lost
voltage vectors according to the fault position and the fault type, and drawing a
vector diagram of fault states, (3) analyzing whether the inverter can continue to run or not under the fault states according to the redrawn
vector diagram, (4) analyzing whether the inverter can run in an original level or not under the fault states according to the redrawn
vector diagram, and (5) for the fault states under which the inverter can continue to run, reselecting
resultant vectors, calculating the action time of all the
resultant vectors, optimizing the switching sequence of the vectors, and forming a redundancy
control impulse train. The method for controlling the NPC three-level inverter fault redundancy solves the problem of reliability of the three-level inverter based on a
software method and effectively improves the reliability of the
system on the basis that the cost of hardware of the
system is not increased.