Fault-tolerant control method for two-level PWM rectifier based on integral anti-saturation

Abstract

The invention discloses a fault-tolerant control method for a two-level PWM rectifier based on integral anti-saturation. The method comprises the steps: switching a PI controller to an anti-saturationPI controller; selecting a sector dividing mode for sector dividing; determining the influence of a fault switching tube on each sector and the change of a basic voltage vector before and after a fault; determining the basic voltage vector of each sector and the action time of the basic voltage vector before the fault; adjusting the action time of the basic voltage vector of the sector influencedby the fault switching tube; determining the on time of a three-phase switching tube; modulating the on time of the switching tube and a triangular carrier wave, determining a PWM pulse of the switching tube, determining the on-off of the switching tube, and completing the anti-integration saturation fault-tolerant control. The method can reduce the pulsation of the current track circle, increasethe control precision of the controller and improve the software fault-tolerant control effect when accurately compensating the sector influenced by the fault switching tube.

Description

technical field [0001] The invention relates to power conversion and control technology, in particular to a fault-tolerant control method of a two-level PWM rectifier based on integral anti-saturation. Background technique [0002] With the development of power electronics technology, three-phase two-level PWM rectifiers have sinusoidal input current, bidirectional flow of energy, and adjustable DC voltage, and are widely used in medium and high-power occasions such as offshore wind power generation and new energy electric vehicles. application. In most cases, the rectifier needs to work uninterruptedly for a long time in a harsh industrial environment, coupled with the unreliability of the power switch tube, improper control and other factors, the failure of the rectifier is inevitable. In order to avoid major accidents, reduce downtime, and restore the performance before the failure as much as possible, it is necessary to implement fault-tolerant control on the system. ...

AI Technical Summary

Problems solved by technology

The above method does not accurately compensate for the impact of the faulty switching tube on each sector, and also compensates for the sectors that are not affected by the switching tube failure, which belongs to overcompensation

The paper "PWM Rectifier Fault-Tolerant Control System Based on NCAV and Circuit Equivalent Replacement" proposed a fault-tolerant control method for PWM rectifiers based on equivalent circuits, but this method did not accurately compensate for the impact of faulty switching tubes on each sector. And in the sectors affected by multiple fault vectors, no compensation is performed, which belongs to undercompensation

The paper "A Rectifier Fault-Tolerant Control Method Based on Space Vector Control" proposed a space vector-based rectifier fault-tolerant control method. This method does not establish a unified sector division function, and cannot implement fault tolerance for multiple bridge arm switch tube failures. Although the precise compensation of a single switching tube can be realized, the negative impact of the faulty switching tube on the system is not considered, and the effect of fault-tolerant control is not optimal.

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