Multi-phase motors have the characteristics of large torque

low torque ripple and high fault tolerance

and are suitable for low-speed and high-power applications. This paper proposes a wind power generation system based on an 18-phase direct-drive permanent magnet synchronous generator. The system consists of an 18-phase motor

a three-phase bridge uncontrolled rectifier

a parallel isolated DC/DC converter and a modular multilevel converter composition. This paper derives through theoretical derivation that at the maximum power point

the output current of the three-phase bridge uncontrolled rectifier is a constant value

so the maximum power tracking can be achieved only by controlling the output current to be constant. Compared with the traditional control method

the complexity of the control method is significantly reduced. In addition

in this paper

the input current of parallel isolated DC/DC converters is distributed in reverse order to adjust the DC/DC duty cycle and maintain the energy balance of the modular multilevel converter. Finally

this paper builds a corresponding simulation model under the Matlab/Simulink software platform

and the simulation results verify the effectiveness of the proposed control method.