Fault-tolerant control method and system for back-to-back converter of wind power generation system

Abstract

The invention discloses a fault-tolerant control method and a fault-tolerant control system for a back-to-back converter of a wind power generation system. The fault-tolerant control method comprisesthe steps of: determining a faulty bridge arm among six bridge arms of the back-to-back converter, reconstructing the rest five healthy bridge arms into a five-bridge-arm converter, connecting corresponding phases of the original faulty bridge arm to one healthy bridge arm by means of a bidirectional thyristor, and defining the healthy bridge arm as a common bridge arm; detecting a current of thecommon bridge arm so as to avoid overcurrent of the common bridge arm under fault-tolerant control, and adjusting a rotation speed of a generator if the current of the common bridge arm is greater than a current early-warning value, thereby controlling a phase difference between corresponding phases at the generator side and the grid side on the common bridge arm to be within 120-240 degrees, andrealizing normal operation of a wind power generation grid-connected system. The fault-tolerant control method can realize the uninterrupted fault-tolerant operation of the system under the fault of the converter, can keep the common bridge arm to be non-overcurrent, and has good robustness.

Description

technical field [0001] The invention belongs to the field of new energy power generation, and relates to a fault-tolerant control method and system in a fault state of a converter of a wind power generation system. Background technique [0002] Since the 1870s, countries that use coal and oil as their main fuels have faced severe environmental pollution. Coupled with the deepening of the dual crisis of limited fossil fuels and reduced reserves, the development and utilization of new energy has become an important part of the world's energy sustainable development strategy. It is an integral part, and wind energy is one of the most potential energy sources in new energy sources. Under the situation of continuous energy shortage, many countries in the world, especially developed countries, are looking for a sustainable new energy source that can replace conventional energy sources and is non-polluting to the environment. The large-scale development and utilization of new ener...

AI Technical Summary

Problems solved by technology

[0003] Since the wind power generation system is a high-order, multi-variable, time-varying non-linear system, and has been in a complex and changeable working environment such as coastal plateaus for a long time, the converter is very prone to failure due to continuous operation with high power and high load. link, the failure of the converter will cause the production process to stop, and may even cause a serious disaster

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