Wide voltage frequency range control system and method for offshore doubly-fed wind power generation system

Abstract

The invention relates to an offshore doubly-fed wind power generation system wide voltage frequency range control system and method, the stator side of a doubly-fed wind power generator (DFIG) is connected with the stator side of the doubly-fed wind power generator (DFIG) through a rotor side converter (RSC) and a stator side network end converter (GSC), the stator side of the doubly-fed wind power generator (DFIG) is connected with the low voltage side of a transformer, and the stator side of the transformer is connected with the low voltage side of the transformer. The direct-current grid side converter (VSC) is connected with the high-voltage side of the transformer; the rotor side converter (RSC) is used for adjusting the stator voltage frequency of the doubly-fed wind generator (DFIG), and the direct-current power grid side converter (VSC) is used for adjusting the stator voltage of the doubly-fed wind generator (DFIG). According to the invention, the stator voltage and the stator voltage frequency can be effectively adjusted, so that the capacity requirements of the rotor winding and the slip ring brush are reduced, and the cost of the rotor converter is reduced.

Description

technical field [0001] The invention relates to a wide voltage and frequency range control system and method for an offshore doubly-fed wind power generation system. Background technique [0002] The development of new energy is an important measure to solve the energy crisis and achieve the goal of carbon neutrality in my country. Offshore wind power resources are sufficient and the utilization rate is high. Wind turbines are constantly developing towards large capacity. At present, many wind turbine manufacturers have developed 5-8MW wind turbines, and they are still developing to larger capacity units. [0003] For wind turbines used in offshore DC wind farms, the permanent magnet direct drive wind power system has become the first choice for large-capacity offshore wind turbines because of its relatively simple control and easy maintenance, but the cost is high. [0004] For doubly-fed wind turbines that account for a large proportion of wind power generation, the incre...

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Problems solved by technology

[0003] For wind turbines used in offshore DC wind farms, the permanent magnet direct drive wind power system has become the first choice for large-capacity offshore wind turbines because of its relatively simple control and easy maintenance, but the cost is high

[0004] For doubly-fed wind turbines that account for a large proportion of wind power generation, the increased difficulty of manufacturing high-power gearboxes is a constraint factor for large-capacity, but more critically, the design of the rotor side is usually The capacity will also increase (megawatt level), and the rotor side brush will be difficult to withstand such a large power and current during high-slip super-synchronous operation. The design of the rotor winding and slip ring brush is very difficult or even difficult to achieve. This has become the main factor limiting the application of doubly-fed models in offshore large-capacity wind turbines

[0005] Therefore, it is necessary to develop a new type of offshore doubly-fed wind power generation system with medium-voltage flexible DC access and a wide-voltage-frequency range control method, which can reduce the slip ratio and slip power in the full wind speed range, and reduce the rotor winding and slip ring electric current. Brush capacity requirements, and reduce the cost of the rotor converter, to a certain extent, to solve the bottleneck problem of doubly-fed machine large-scale

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