Virtual synchronous generator control strategy of M3C converter in fractional frequency offshore wind power system

Abstract

In this paper, the control strategy of modular multilevel matrix converter (M3C) is studied in the scenario of fractional frequency offshore wind power. The M3C system is compared with the traditional rotating synchronous generator system in terms of structural parameters and motion equations, and the feasibility of the M3C inverter to simulate the external characteristics of the synchronous generator is analyzed. With the goal of converter participating in system frequency regulation and stabilizing system voltage, based on the control theory of virtual synchronous generator (VSG), the control scheme design of virtual synchronous generator of M3C converter is completed, and a control strategy suitable for fractional frequency offshore wind power M3C converter is established. Finally, using PSCAD/EMTDC simulation platform, the correctness of this control strategy is verified. With the same system structure and parameters, the control strategy is compared with the decoupling control strategy of double dq coordinate transformation. The results show that the VSG control strategy can make the frequency converter have inertia and damping characteristics. The VSG control can participate in the system frequency regulation, and has good control response characteristics.

Keywords

• offshore wind power
• fractional frequency transmission system (ffts)
• modular multilevel matrix converter (m3c)
• frequency regulation of the system
• virtual synchronous generator control
• inertial damping characteristics