Power generating unit

The invention discloses a power generating unit which comprises a box and power generating equipment arranged in the box. A cooling air duct is formed in the box, the power generating equipment is disposed in the cooling air duct and divides the cooling air duct into a first cooling air passage and a second cooling air passage, the power generating equipment comprises a frequency changer, a motor fan, a motor main body and an engine which are sequentially arranged in the box along the direction of cooling air, the box comprises a frequency changer cover containing the frequency changer, the frequency changer comprises a frequency changer front diversion cover and a frequency changer rear diversion cover which are detachably connected, an air inlet is formed on the lower portion of the frequency changer front diversion cover, and the cooling air enters the lower portion of the frequency changer front diversion cover from the air inlet, upwards enters the frequency changer rear diversion cover and downwards enters a motor fan cover along the frequency changer rear diversion cover to form an n-shaped cooling air duct of the frequency changer. By designing the cooling air passages, matching of parts is enabled to be more close, loss of the cooling air during flowing is reduced, cooling efficiency is improved, production cost,size and weight of the power generating unit are greatly lowered, and the power generating unit is enabled to be lighter and convenient to move.