Current source converter asymmetric multi-level modulation method for flexible interconnection of distribution network

The invention relates to an asymmetric multi-level modulation method of a current source converter for flexible interconnection of a distribution network. The method comprises the following steps: step 1, dividing all non-zero switching states of the asymmetric multi-level current source converter into five types of PWM current vectors; 2, calculating the area of a sector where the reference current vector Ir is located according to the phase angle theta and the modulation factor ma; 3, selecting a proper vector synthesis method, and determining action time of all vectors by combining the value of the phase angle theta; 4, when the I-type current vector and the II-type current vector act, directly obtaining a current source switch state; and when the III-type, IV-type and V-type current vectors act, a proper switching state is selected according to the principle of balancing the direct-current bus current, and corresponding gate pole control signals are generated and sent to each current source converter. Acc