The permanent magnet synchronous wind turbine has become another important type of wind turbine after the doubly-fed induction wind turbine due to its advantages of small mechanical loss, high operating efficiency, and low maintenance cost, and has gradually been put into use. The basic structure of the permanent magnet synchronous wind power generation system is shown in Figure 1. It is mainly composed of a wind turbine, a permanent magnet synchronous motor, a frequency converter, and a transformer.

(1) Basic principles

The basic principle of permanent magnet synchronous wind power generation is to use wind force to drive the blades of the wind turbine to rotate and drag the rotor of the permanent magnet synchronous generator to rotate 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 generator, and the rotor is a permanent magnet structure, which does not require an external excitation power supply and improves efficiency.

Its variable frequency and constant speed control are 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 as the power grid through the frequency converter, so as to realize the grid connection of wind power generation, so the capacity of the frequency converter is the same as the capacity of the system.

(2) Technical features

Over the past few decades, permanent magnet synchronous generators have become increasingly attractive due to improvements in the properties of permanent magnet materials and power electronics.

The wind power generation system using the 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 being lightweight, high efficiency, high power factor, and good reliability;

2) The variable speed operation range is wide, and it can run super synchronously or subsynchronously;

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 need for a gear speed increaser box in the wind power generation system, reducing the maintenance work of the generator, and reducing noise. It is a direct-drive permanent magnet wind power generator system.

3) Applicable occasions

1) In areas where power facilities are scarce, transportation is inconvenient, and conventional fuels are lacking, but wind resources are abundant, it can solve some electrical problems, such as providing power for highway lighting equipment;

2) In wind farms with relatively small unit capacity, the permanent magnet synchronous power generation system can be efficiently connected to the grid for power generation;

3) Provide AC or DC power for remote users with light loads such as rural areas, pastoral areas, border posts, and meteorological stations.