Multifunctional test system of wind turbine generator system

The invention belongs to the technical field of tests of wind turbine generator systems, and discloses a multifunctional test system of a wind turbine generator system. The system comprises a generator set, a grid-tied converter and a feed switch cabinet which are sequentially in electric connection, comprises an industrial power grid, a high-voltage switch cabinet, a step-down transformer, a power receiving switch cabinet, a rectifier cabinet and a common direct current bus which are sequentially in electric connection, and further comprises a first inversion cabinet in electric connection with the common direct current bus, a second inversion cabinet in electric connection with the common direct current bus, a first double-shaft-extension dragging motor in electric connection with the first inversion cabinet, a second double-shaft-extension dragging motor in electric connection with the second inversion cabinet and a first coupler used for being selectively connected with a projecting shaft end of the first double-shaft-extension dragging motor and a projecting shaft end of the second double-shaft-extension dragging motor. The system has the advantages of being capable of meeting various test requirements of various common wind turbine generator system models and having high economic efficiency and flexibility.