Tri-level four-leg T-shaped fault-tolerant converter and control method thereof

Abstract

The invention discloses a tri-level four-leg T-shaped fault-tolerant converter and a control method thereof. The fault-tolerant converter comprises a DC input circuit, a tri-level T-shaped topology device, a failure isolation circuit, a redundant leg, a fault-tolerant bridge and an AC output circuit, wherein a power switch tube corresponding to the redundant bridge is controlled to be switched on in the normal operating state when the neutral-point voltage of a DC bus fluctuates sharply, the neutral-point voltage is quickly adjusted to be balanced by introducing inductive current, over-voltage breakdown of the power switch tube caused by sharp fluctuation of the neutral-point voltage is prevented, and a bidirectional controllable thyristor corresponding to the fault-tolerant bridge is controlled to be switched on to enable the redundant bridge to replace a broken bridge for fault-tolerant operation when a failure occurs. According to the fault-tolerant converter, fault tolerance of open circuit and short circuit failures of the switch tube and legs can be achieved, and output power and DC voltage utilization rate can not be reduced. The tri-level four-leg T-shaped fault-tolerant converter can be applied to an AC motor driving system or a grid-connected power generation system, so that the system has a better fault-tolerant operation function.

Description

Technical field [0001] The invention relates to the technical field of multi-level converters and fault tolerance, in particular to a three-level four-arm T-type fault-tolerant converter and a control method thereof. Background technique [0002] A converter is an electronic electronic device used to realize the conversion of DC to AC or AC to DC power. According to the nature of the DC side power supply, the converter can be divided into a voltage source type converter and a current source type converter. Traditional two-level converters are usually used in low-voltage and low-power applications. The goal of future power electronic technology research is high power density, high efficiency, and high performance. In the solution to achieve high-power conversion, the multi-level voltage source converter has become a high-voltage power converter due to its various control methods, low output waveform harmonic distortion rate, low voltage stress of power devices, and high inverter ...

AI Technical Summary

Problems solved by technology

However, due to the overall limitation of the current level of power electronics technology, the reliability of the converter system is much lower than that of other parts of the electromechanical device

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