Wind energy is a clean, safe, and renewable green energy source. With the increase of people's awareness of environmental protection in recent years, it has gradually become a new energy source developed and utilized by countries all over the world. For areas not covered by the power grid and some special areas, such as pastoral areas, forest areas, islands, and border posts, a large number of off-grid generators are still needed to make up for the shortcomings of the large power grid.
1. Due to the wide range of wind speed changes, the output voltage of wind generators (especially permanent magnet generators) fluctuates in a wide range. Therefore, this off-grid generator often cannot be directly connected to the load. Instead, it charges the battery through a rectifier, stores electrical energy, and supplies power to the load through the battery; it can also use a controllable rectifier regulator to make the generator at the same time supply power to the load and battery.
2. In recent years, small wind turbines have mostly adopted permanent magnet generators, which improved the efficiency of the generator, reduced costs, and increased reliability. Most off-grid wind turbines operate in a single machine. After the three-phase AC voltage output by the generator is rectified and stabilized, it charges the battery and supplies power to the load.
The following points should be paid attention to when designing wind turbines:
(1) The operating environment of the generator is harsh, and the generator is required to have high safety and reliability, and be able to prevent rain, snow, and dust.
(2) When the generator is directly driven by the wind wheel (the commonly used speed-increasing gearbox is omitted), the rated speed of the generator is required to be low.
(3) The generator's initial pressure build speed is required to be low to maximize the utilization factor of wind energy.
(4) The starting resistance torque of the generator is as small as possible so that the generator can start well at a lower wind speed, and the utilization of wind energy is also improved.
3. The wind generator uses NdFeB permanent magnets, eliminating the need for brushes and slip rings, reducing maintenance, and improving reliability; the rated speed of the generator is low, and it is directly coupled and driven by the wind wheel, which simplifies the structure of the generator. The weight of the device is reduced, and the cost is reduced; The efficiency of the generator is higher, the starting resistance torque is small, and it is easy to start at lower wind speeds, which improves the low-speed power generation performance of the wind generator and improves the utilization of wind energy.