Direct-driven wind turbine generator converter grid-connected system stabilizing method

Abstract

The invention discloses a direct-driven wind turbine generator converter grid-connected system stabilizing method. A wind turbine generator can operate stably when connected to the power grid, and the stability margin of the whole system is improved. A sequence impedance model Zi of the direct-driven wind turbine generator converter is firstly constructed, then the stability margin of a Zg / Zi frequency domain curve of a current converter grid-connected system is judged according to a Nyquist stability criterion, and control parameters of a current loop of the converter are optimized according to a judgment result, so that the stability margin of the converter grid-connected system is optimal. According to the stabilizing method disclosed by the invention, real-time impedance measurement of the direct-driven wind power plant and system impedance adjustment during a fault are realized, a long-distance large-scale offshore direct-driven wind power plant grid-connected technology is ensured to have a relatively high stable operation margin, the problem of oscillation caused by low stability margin of an impedance curve due to setting of system control parameters at the present stage is solved, and the method has very strong engineering significance.

Description

technical field [0001] The invention relates to the technical field of renewable energy power generation systems, in particular to a method for stabilizing a grid-connected system of a direct-drive wind turbine converter. Background technique [0002] Permanent magnet synchronous generators have the advantages of low cost, high efficiency and high output power, and are widely used in offshore wind farms. Due to its advantages of low platform cost and low power loss, the DC collection method has been widely used in long-distance large-scale offshore direct-drive wind farm delivery systems. However, the system using DC series-parallel topology has the disadvantages of low fault tolerance and high control strategy requirements. The failure of a single wind turbine may lead to the failure of the entire system. As the installed capacity of direct-drive wind turbines increases sharply and the transmission distance becomes farther and farther, the oscillation problem of the direct...

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