What is the principle of a permanent magnet synchronous wind turbine?What are the characteristics and applications?

China’s are rich in wind energy resources , and the wind energy potential that can be developed is huge. According to the relevant information, China’s terrestrial wind energy resources can be developed at 2.38 billion kilowatts, and offshore wind energy resources can be developed at about 200 million kilowatts. China’s wind energy resources are relatively concentrated, and the development of potential wind energy resources in the “Three North” regions (North China, Northeast China and Northwest China) and the southeast coastal areas and coastal islands accounts for about 80% of the country. The geographical distribution of wind energy resources and coal resources has a high degree of coincidence, and the power load is inversely distributed.

During the “Twelfth Five-Year Plan” period, China’s wind power installed capacity will account for a larger proportion of total power generation capacity. For power grid safety considerations, wind turbines must be “prevented by the wind” under the “low voltage ride through” guarantee. According to relevant sources from the Energy Research Institute of the National Development and Reform Commission of China, the cost of land-based wind power will be equal to that of coal-fired power in 2020. After that, wind power will gradually be separated from state subsidies, and “cost reduction” has become a new “bottleneck” for the future development of the wind power industry.

Due to the advantages of low mechanical loss, high operating efficiency and low maintenance cost, permanent magnet synchronous wind turbines have become a major wind turbine type after the doubly-fed induction wind turbines, and have been widely used. The permanent magnet synchronous wind is mainly composed of a wind turbine, a permanent magnet synchronous engine, a frequency converter and a transformer.

(1) Basic principles

Generator

The basic principle of permanent magnet synchronous wind power generation is to use the wind to drive the wind turbine blade to rotate, and to rotate the rotor of the permanent magnet synchronous generator to realize power generation. The permanent magnet synchronous wind power generation system is similar to the cage type variable speed constant frequency wind power generation system, except that the generator used is a permanent magnet type generator, and the rotor is a permanent magnet type structure, and the external excitation power supply is not required, thereby improving the efficiency. Its variable frequency constant speed control is realized in the stator circuit, and the variable frequency alternating current of the permanent magnet synchronous generator is converted into the alternating current of the same frequency of the power grid through the frequency converter to realize the grid connection of the wind power generation, so the capacity of the frequency converter and the system The rated capacity is the same.

(2) Technical characteristics

In the past few decades, permanent magnet synchronous generators have become increasingly attractive due to the performance of permanent magnet materials and improvements in power electronics. A wind power generation system using a permanent magnet synchronous generator has the following characteristics:

1) The permanent magnet synchronous generator system does not require an excitation device, and has the advantages of light weight, high efficiency, high power factor, and good reliability;

2) The variable speed operation range is wide, which can be super-synchronous operation or sub-synchronous operation;

3) The rotor has no excitation winding, the magnetic pole structure is simple, the inverter capacity is small, and it can be made into a multi-pole motor;

4) The synchronous speed is reduced, so that the wind turbine and the permanent magnet generator can be directly coupled, eliminating the gear speed increasing box in the wind power generation system, reducing the maintenance work of the generator and reducing the noise, so that the direct drive permanent magnet wind power generation Machine system.

(3) Applicable occasions

1) In areas where power facilities are scarce, transportation is inconvenient, and conventional fuels are scarce, but wind resources are abundant, some of the electricity problems can be solved, such as providing power for highway lighting equipment;

2) In a wind farm with a relatively small single unit capacity, the permanent magnet synchronous power generation system can efficiently generate electricity on the grid;

3) Provide AC or DC power for remote, lightly loaded users such as rural areas, pastoral areas, border guard posts, and meteorological stations.

 

 

 

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Post time: Aug-20-2018
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