Currently "Cooling Fan Manufacturer" large-capacity wind turbine has a lot of adjusting frequency control mode, this type of invert is mainly dependent on imports, the price is expensive. Currently 1kw fan following power levels, especially air conditioners and other household fan has permanent magnet brush less DC motor drives, and the use of wind speed transfer mode. 1 ~ 10kw power range of fans a huge amount, the basic use of induction motor drive and adjust the outlet opening of the methods adopted to regulate air flow. For fans in this power range "Cooling Fan Manufacturer", the use of permanent magnet brush less DC motor drive to replace the original induction motor drive has great advantages. Including straight "Cooling Fan Manufacturer" flow fan works with work flow.