There are two advantages in reducing the mechanical transmission: on the one hand, for a given size gearbox, the introduction of the variable speed drive can increase the rated power of the centrifugal fan; on the other hand, for a given rated fan, The introduction of the way can reduce the size of the gearbox. Rated power of 500kW fan for centrifugal fan manufacturers, the use of variable speed mode is not cost-effective economy. The cost of a constant-speed fan with a relatively low rated power is relatively low for gearboxes and other transmissions, and the cost of the windings in variable speed wind turbines is relatively high, so whether the system uses variable speed Drive the way to consider the size of the fan energy level. When the energy level rose to more than 1MW, the variable speed wind power system can be very obvious to show its superiority. The use of variable speed fan can also effectively reduce the fan noise. In the case of low wind speed, the fan speed is very low, greatly reducing the noise generated. And when the wind speed becomes high, the increase in winds overshadows the increase in fan noise due to the increase in fan speed.
Variable speed wind power generation system is the power flow after the transfer to the grid, which can be weakened to some extent due to wind and mechanical systems on the instantaneous changes in the impact of the system. When a sudden wind arrived at the fan, the fan speed increases, so that the mechanical inertia part of the system to absorb the excess wind energy, through the variable flow device after the variable speed wind power system can still provide continuous and stable power to the grid. When the wind speed decreases, the fan speed is also reduced, inertial energy storage part of the storage energy can be released. It can be seen that the fluctuation of the wind speed is allowed in the unidirectional rotation of the wind turbine. Even if the aerodynamic moment of the fan is rotating on the wind tower, the natural characteristics of the fan and the blade of the fan can still cause the system to transmit constant electric energy to the grid. The speed of the fan will be effectively modulated according to the change in wind speed.