Research On Hybrid Excitation Outer Rotor Synchronous Wind Generator

Wind power has become the fastest-growing energy of the world. In the past half of centuries, with the researchers'tireless efforts and the government's strong support, wind power technology is developed rapidly, the technical level, cost-effective and capacity is made a considerable progress, more and more large wind farms are built and putted into operation, which provide clean energy to the grid.In the field of wind power generation, permanent magnet synchronous generator with high-efficiency is attracted researcher's attention. However, the air-gap flux of permanent magnet synchronous generator is difficult to regulated, which limit its application in large wind turbines. Despite the researchers have made a number of approach in voltage regulation of permanent-magnet generator, but the complicated technique and high cost lead it difficult to achieve mostly. In recent years, Hybrid excitation synchronous generator is impressive, which has a wide range adjustment in air-gap flux, achieve real-time control on generator output voltage, extend the scope of wind speed and improve the efficiency of wind power generation. This paper proposes a new-type wind-generation outer-rotor synchronous generator with hybrid excitation. There has a additional excitation stator windings in this generator, which inject DC current can regulate the air-gap flux achieve magnetizing or demagnetizing, without brushes and slip rings.In this paper, different types of hybrid excitation machine are investigated; a new type topology of hybrid excitation outer-rotor wind synchronous generator is present and its principles of operation and characteristics are studied in theoretical; the three-dimensional models and magnetic filed analysis are made, the method of electromagnetic design is discussed; the MATLAB simulation models of the hybrid excitation generator and system are established and analyzed; a rated power of 200W, rated voltage of 110V, rated speed of 400 r/min wind generator prototypes are designed and trial-manufactured,which a series of tests are made. The testing results show that wind-generation outer-rotor synchronous generator with hybrid excitation has a good output voltage waveform, as well as the good ability of voltage regulation,which meet the requirements of high-performance wind turbines. Based the mentioned work, a rated voltage of 110V, rated power of 4kW wind-generation outer-rotor synchronous generator with hybrid excitation is designed.