Abstract: In order to meet the power control requirements of the distributed microgrid for wind turbines,an umbrella shaped wind turbine with automatic output power control is proposed. Taking the 5 kW umbrella shaped wind turbine as the research object,according to its different contraction angles under the conditions of super-rated wind speed,the aerodynamic characteristics and flow field characteristics are numerically simulated. Some conclusions are obtained. First of all,when the incoming wind speed exceeds the rated wind speed,umbrella-shaped wind turbines can effectively control the increase of output power by increasing the contraction angle of the wind wheel;Secondly,when the incoming wind speed is 18 m/s and the contraction angle is 60 degrees,the output power of the umbrella shaped wind turbine is 39.2% of the rated power;The increase in the contraction angle of the umbrella wind turbine will reduce the pressure difference between the front and rear surfaces of its blades;Increasing the contraction angle of umbrella-shaped wind turbines will gradually move the flow separation position to the leading edge of the blade;The speed loss of the root of the umbrella shaped wind turbine affected by the central vortex is greater than that of the tip. Increasing the contraction angle is not conducive to the recovery of its wake speed. When the contraction angle is 60 degrees,the wake velocity at 11 D（D is the diameter of the wind wheel）behind the wind wheel only recovers to 89.4% of the incoming wind velocity. Finally,through wind tunnel tests,the output power changes of umbrella shaped wind turbines under different contraction angles are tested. The test results verify the accuracy of the numerical research conclusions.