Power Oscillation Suppression Method for Multi-Parallel Synchronverters

It is a promising solution to connect distributed generators (DGs) units to the grid via synchronverter. However, the differences between the parallel system composed of two synchronverters will affect the transient stability of the system, the fixed parameters cannot be applied to both steady state and dynamic state, which could threaten the stable operation of the system. Variable parameters using frequency or rate of change of frequency (ROCOF) are affected by grid voltage unbalance and harmonics. To solve this problem, a centralized virtual electromagnetic torque compensation control is proposed. In this paper, the reason of power oscillation of multi-VSG system is analyzed by taking the parallel system as an example. Based on this, a centralized virtual electromagnetic torque compensation control is proposed, and compared with the traditional control mode, the results show that the proposed control strategy can effectively reduce the oscillation frequency and attenuation coefficient of the system. A simulation model is built in Matlab/Simulink to verify the effectiveness and superiority of the proposed control strategy over the traditional control.