Fault tolerant control method for open circuit faults of three-phase bridge PWM rectifier switching tube

Abstract

The invention discloses a fault tolerant control method for open circuit faults of a three-phase bridge PWM rectifier switching tube and belongs to the field of three-phase AC-DC (Alternating Current-Direct Current) conversion. The invention solves problems that multi-tube fault tolerant control is imperfect, the hardware cost is high and the like of the conventional fault tolerant scheme. According to the method, the characteristic that a local space voltage vector changes when a fault occurs to any switching tube of a three-phase bridge PWM rectifier is utilized; a PWM switching mode is corrected, i.e., a fundamental voltage vector is selected again and the action sequence and time is adjusted; and composition is conducted again to recover or approach an original rotary reference voltage vector, so that the normal operation of a system is maintained, and the fault tolerant control operation is achieved. According to the method disclosed by the invention, the effective fault tolerant control operation can be achieved when an open circuit fault occurs to a single switching tube and multiple switching tubes in the three-phase bridge PWM rectifier, and only a software algorithm is required. The method is simple and easy to achieve while no additional hardware cost is required.

Description

technical field [0001] The invention discloses a switch tube open-circuit fault fault-tolerant control method for a three-phase bridge PWM rectifier, belonging to the field of three-phase AC-DC conversion. Background technique [0002] Compared with the traditional uncontrolled rectification or phase-controlled rectification scheme, the three-phase bridge PWM rectifier has the advantages of controllable DC voltage, unit power factor, small grid-side current harmonics, and bidirectional flow of energy. Power occasions have been widely used. In PWM rectifiers, faults occur frequently due to the limitations of power switching devices' withstand voltage, current and impact resistance, or improper control, which seriously affects the operational reliability of the system. The survey shows that about 38% of the power conversion system failures are caused by the failure of power switching devices, mainly including short-circuit faults and open-circuit faults. The former will caus...

AI Technical Summary

Problems solved by technology

From the perspective of reliability, it is not comprehensive enough to study only single-tube faults, and it is necessary to study the fault-tolerant method under simultaneous open-circuit faults of multiple tubes

[0004] In summary, the fault-tolerant control method proposed in the existing literature for the open-circuit fault of the switching tubes of the three-phase bridge PWM rectifier still has many shortcomings in terms of realizing multi-tube open-circuit fault tolerance, no hardware cost, and simple algorithm.

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