An 18-phase wind power generator DC grid-connected structure and its control method

Abstract

The invention discloses an 18-phase wind generator direct current grid-connected structure and a control method thereof. The structure comprises a 18-phase direct drive permanent magnet wind power generator, six three-phase uncontrollable rectifying bridges, 6m parallel isolation type full bridge DC-DC converters and 6m half bridge sub modules; each set of three-phase alternating current windingsof the 18-phase generator passes through one corresponding three-phase uncontrollable rectifying bridge to be subjected to current conversion and then to be connected to m parallel isolation type fullbridge DC-DC converters; each DC-DC converter is connected with one half-bridge sub module; the positive electrodes and negative electrodes at the output ends of the 6m half bridge sub modules are connected in sequence, and finally are connected with an electric reactor in series to form a series circuit to be connected to a direct current power transmission network; the parallel isolation type full bridge DC-DC converters adopt the maximum power tracking control, and the half bridge sub modules are controlled through direct current transmission current. By virtue of the structure, the voltage level of the generator stator winding is lowered, system stability is improved, and the construction cost of a power plant is lowered.

Description

technical field [0001] The invention belongs to the technical field of wind power generation, and in particular relates to a DC grid-connected structure of an 18-phase wind power generator and a control method thereof. Background technique [0002] With the development of society, energy issues have become increasingly prominent. Seeking various new energy sources to replace the increasingly depleted traditional fossil energy sources has become a research hotspot in various countries. [0003] As a clean energy, wind energy has great development potential. There are huge wind energy resources in the sea, so the relevant issues of offshore wind farms have attracted a large number of scholars at home and abroad to study. The main challenge of offshore wind farms is how to transmit the generated electricity to land in an efficient and economical way. [0004] Traditional high-voltage AC transmission requires parallel connection of additional reactive power compensators to ab...

AI Technical Summary

Problems solved by technology

However, since the wind energy received by each wind turbine is different, resulting in different output voltages, it may be potentially dangerous to directly connect them in parallel

[0007] The high-power direct-drive permanent magnet wind turbine has a low speed and is difficult to increase the terminal voltage. It needs to be connected to a high-voltage AC power grid through an isolated step-up transformer. It is difficult to build in an offshore wind farm and the maintenance cost is high.

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