Wind turbine converter and its low voltage ride through
In recent years, with the energy crisis and environmental issues becoming increasingly prominent, countries around the world are vigorously developing renewable energy businesses such as wind power generation, and their related technologies are developing rapidly, from stall type to variable speed constant frequency wind power systems, from gearboxes to direct Driven wind power systems, China's wind power installed capacity has also achieved rapid growth in recent years. In order to improve the efficiency of wind energy utilization and reduce the cost of wind power, the large-scale single-machine capacity of wind turbines is a major trend in the development of wind power technology. The use of variable-speed pitch adjustment technology has become an important feature of large-scale wind turbines above mw level; the current variable-speed constant-frequency wind power In the system, the doubly-fed induction generator (dfig) uses the doubly-fed induction generator (dfig) to have the largest market share, and the direct-drive system using permanent-magnet synchronous generator (pmsg) is very developed. fast. As the installed capacity of wind power generation continues to increase, its impact on the power grid can not be ignored. Many countries have formulated new wind power grid-connected rules, which stipulate functions such as low voltage ride through and reactive power support. China will also have Similar rules were introduced [1-3].
This paper starts from three typical wind power systems, including stall-type wind power systems, doubly-fed and permanent magnet direct-drive variable-speed constant-frequency wind power systems. According to the gearbox structure and generator type, the current wind power system structure is discussed, and the wind turbine used is discussed and analyzed. The wind power converter as the interface between wind power generation and power grid is explained. With the increase of the single unit capacity of the wind turbine, the high power multilevel converter will be used more; the low voltage crossing and reactive power of the wind power system Power support, etc. were analyzed. For wind turbine generators, converters and low voltage ride-through capabilities, the related products and technologies of different wind power companies are introduced.
2 Several typical wind power systems
The wind power generation system can be divided into a stall type and a variable speed constant frequency type according to the generator speed. The variable speed constant frequency can be divided into a double feed type and a direct drive type; according to the transmission chain composition, it can be divided into a gear box and a direct drive. Type, there are gearboxes can be divided into multi-stage gear + high-speed generator type and single-stage gear + low-speed generator type. There are different classification methods from different angles. This article discusses from the following typical wind power generation systems.
