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Two-level PWM rectifier fault-tolerant control method based on sector buffer

A fault-tolerant control and rectifier technology, applied in electrical components, output power conversion devices, AC power input conversion to DC power output, etc., can solve problems such as compensation, failure to establish a unified sector division function, and under-compensation

Active Publication Date: 2019-01-01
NANJING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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.

Method used

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  • Two-level PWM rectifier fault-tolerant control method based on sector buffer
  • Two-level PWM rectifier fault-tolerant control method based on sector buffer
  • Two-level PWM rectifier fault-tolerant control method based on sector buffer

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Effect test

Embodiment 1

[0163] In this embodiment, the three-phase two-level PWM rectifier is divided into eight sectors to illustrate the single-tube fault S1. When a short-circuit fault occurs in the S1 tube, it will be converted into an open-circuit fault by the thermal fuse. When an open-circuit fault occurs in S1 According to Table 16, the fault-tolerant buffer control method is described by comparing the sector changes under the three states of fault-tolerant control, single-sector fault-tolerant buffer control, and double-sector fault-tolerant buffer control in a single cycle.

[0164] Table 16 Comparison of three-state sectors in a single cycle of eight sectors under S1 switch tube failure

[0165]

[0166] Schematic diagram of the sector and buffer sector distribution affected by the fault switch tube of the three-phase two-level PWM rectifier S1 tube fault in the eight-sector division mode is as follows Image 6 As shown, in the case of S1 tube failure, for the sector not affected by the...

Embodiment 2

[0168] This embodiment is described by taking a three-phase two-level PWM rectifier with multi-transistor faults in an eight-sector division mode.

[0169] When two switching tubes in the three-phase two-level PWM rectifier fail at the same time, such as figure 2 As shown, it will be divided into the following four situations:

[0170] a. The two upper and lower switching tubes of the same bridge arm fail at the same time;

[0171] b. Two upper tubes of different bridge arms fail at the same time;

[0172] c. Two lower tubes of different bridge arms fail at the same time;

[0173] d. One upper tube and one lower tube of different bridge arms are faulty.

[0174] Since the short-circuit fault can be converted into an open-circuit fault through the thermal fuse, after other fault diagnosis, the switching tube fault can also be converted into an open-circuit fault by turning off the controller. Here, the open-circuit fault is used for description.

[0175] For case a, the si...

Embodiment 3

[0179] In this embodiment, the three-phase two-level PWM rectifier is divided into twelve sectors with a single-tube fault S1 to illustrate. When a short-circuit fault occurs in the S1 tube, it will be converted into an open-circuit fault by the thermal fuse. When an open-circuit fault occurs in S1 At this time, according to Table 17, the fault-tolerant buffer control method is described by comparing the sector changes under the three states of fault-tolerant control, single-sector fault-tolerant buffer control, and double-sector fault-tolerant buffer control in a single cycle.

[0180] Table 17 Comparison of three-state sectors in a single cycle of twelve sectors under S1 switch tube failure

[0181]

[0182]

[0183] Schematic diagram of the sector and buffer sector distribution affected by the fault switch tube of the three-phase two-level PWM rectifier S1 tube fault in the twelve-sector division mode is as follows Figure 7 As shown, in the case of S1 tube failure, f...

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Abstract

The present invention discloses a two-level PWM rectifier fault-tolerant control method based on sector buffer. The method comprises the steps of: selecting a sector division mode to perform sector division; determining influences of a fault switch tube on each sector and change of basic voltage vectors before and after faults; determining the basic voltage vector of each sector and action time ofthe basic voltage vectors prior to faults; selecting a normal sector of a reference voltage rotation vector translated from a fault section to a normal section as a buffer section; regulating actiontime of the basic voltage vectors of the sectors influenced by the fault switch tube and the buffer sector; and determining the conduction time of a three-phase switch tube, and modulating the switchtube conduction time and a triangular carrier to determine a switch tube PWM pulse, determine on-off of the switch tube and complete the buffer fault-tolerant control. The two-level PWM rectifier fault-tolerant control method can further reduce the negative influence caused by the fault switch tube through the sector buffer method while precious compensation for the sectors influenced by the switch tube faults so as to improve the fault-tolerant control effects on the single-tube faults and the dual-tube faults.

Description

technical field [0001] The invention relates to a sector buffer-based two-level PWM rectifier fault-tolerant control method, which belongs to the field of power conversion and control. 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 factors such as unreliability and improper control of the power switch tube, the failure of the rectifier is inevitable. In order to avoid major accidents and reduce downtime, and restore the performance before the failure as much as possible, it is necessary to implement fault-tolerant control on the system. [0003] The exist...

Claims

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Application Information

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IPC IPC(8): H02M7/219H02M1/32
CPCH02M1/32H02M7/219H02M1/325
Inventor 冯延晖秦伟邱颖宁黄凯
Owner NANJING UNIV OF SCI & TECH
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