基于直接电压的虚拟同步发电机预同步控制策略

Direct Voltage-Based Pre-Synchronization Control Strategy for Virtual Synchronous Generators

针对虚拟同步发电机(VSG)在并网瞬间产生冲击电流的问题,提出一种基于直接电压计算的预同步控制方法,通过直接获取并网点两端的电压大小进行计算调制后,作为预同步的频率补偿量,无需锁相环且输出连续,并且设计一个一阶惯性环节缓解并网后由于预同步模块退出导致的频率跳变。在MATLAB/Simulink软件搭建虚拟同步发电机并网仿真模型并进行实验验证,结果表明所提策略能有效降低并网前后频率波动和电流冲击。

Aiming at the problem of the virtual synchronous generator(VSG)generating impulse current at the moment of grid connection,a pre-synchronous control method based on direct voltage calculation is proposed,in which the voltage magnitude at the two ends of the grid connection point is obtained directly and modulated for calculation,which is used as the frequency compensation for pre-synchronization,with no need for phase-locked loop and with continuous output,and a first-order inertia link is designed to mitigate frequency jumps due to the withdrawal of pre-synchronization module after grid connection.Finally,a virtual synchronous generator grid connected simulation model is constructed in MATLAB/Simulink to verify that the proposed strategy effectively reduces the frequency fluctuation and current impulse before and after grid connection.