Fault-tolerant control method and system for open-circuit fault of T-type three-level inverter

Abstract

The invention discloses an open-circuit fault diagnosis and fault-tolerant operation method and system for a T-type three-level inverter. The method comprises the following steps: controlling the T-type three-level inverter to operate by adopting a seven-section SVPWM modulation mode; sampling the inverter bridge arm output and direct current side midpoint voltage at the same time to obtain a low-frequency voltage signal, and performing coordinate transformation to obtain an equivalent output voltage vector track of the inverter; through calculating voltage vector tracks under different faultconditions and operation states, establishing a fault characteristic value truth table, and judging the current fault type of a system according to the characteristic value of the current system and the fault characteristic value truth table; finally switching a corresponding control scheme, and realizing fault-tolerant operation of the T-type three-level inverter by using a redundancy vector equivalent replacement method.

Description

technical field [0001] The invention relates to the field of fault-tolerant control of T-type three-level inverters, in particular to a fault-tolerant control method and system for open-circuit faults of T-type three-level inverters. Background technique [0002] T-type three-level inverters have fault-tolerant operation capability under certain fault conditions, and are widely used in power systems, aerospace, metallurgy and mining, rail transit and other fields. These occasions require high power supply continuity, and long-term power outages may cause major economic losses or accidents, which puts forward higher requirements for T-type three-level inverters to work stably for a long time. The fault-tolerant operation of the inverter under partial fault conditions can greatly improve the power supply continuity of the system. The prerequisite for the inverter to achieve fault-tolerant operation is that the system diagnoses the fault and quickly realizes the switching of t...

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Problems solved by technology

[0004] The main purpose of the present invention is to propose a T-type three-level inverter open-circuit fault diagnosis and fault-tolerant control method and system, which can solve the problem in the prior art that the fault-tolerant control system diagnosis method cannot be applied to various load sizes and load powers. factor and the problem of load imbalance

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