A grid-friendly retrofit method for constant-speed wind turbines

Abstract

The invention discloses a power grid friendly transformation method suitable for a constant-speed wind turbine generator set. According to a constant-speed wind turbine generator set canonical topology structure composed of a wind turbine, a gearbox, an induction generator and a compensating capacitor, a set of power grid friendly transformation device composed of a doubly-fed motor, a permanent magnet motor and an alternating-direct-alternating current converter is newly added on the basis of the equipment. The power grid friendly transformation device is reasonably controlled, the power grid friendly degree of the constant-speed wind turbine generator set can be improved, and the functions of smoothing output power, achieving low voltage ride through and enhancing the reactive supporting capacity in the low voltage ride through period are specially achieved. The method is suitable for independently carrying out power grid friendly transformation on the single constant-speed wind turbine generator set and also suitable for carrying out power grid friendly transformation on a plurality of constant-speed wind turbine generator sets with approximate wind conditions at the same time, and the requirements of a power grid for smoothing the output power of the wind turbine generator set and having the low voltage ride through capacity and the reactive supporting capacity are met.

Description

technical field [0001] The invention belongs to the field of wind power generation, and relates to a grid-friendly transformation of wind turbines, in particular to a grid-friendly transformation method suitable for constant-speed wind turbines. Background technique [0002] With the increasing penetration of wind power in the power grid, the problem of insufficient grid friendliness of wind turbines has become one of the main factors restricting the development of the wind power industry, and this problem has received increasing attention. [0003] Most of the wind turbines installed in the early stage were constant-speed wind turbines. This type of wind turbine was "rigidly" connected to the grid. The fluctuation of wind speed was directly reflected in the fluctuation of the active power injected into the grid by the wind turbine, which reduced the power quality of the access point. [0004] In addition, constant-speed wind turbines do not have low-voltage ride-through cap...

AI Technical Summary

Problems solved by technology

At the same time, aiming at the root cause of the instability of the speed and terminal voltage of the constant-speed wind turbine during the grid voltage drop-the slip exceeds the critical value, the slip is limited by increasing the frequency and voltage amplitude of the stator winding of the induction generator, thereby Solve the low voltage ride through problem of constant speed wind turbines

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