交直流混合微电网并联接口变换器的VSG控制策略

VSG Control Strategy of AC/DC Hybrid Microgrid Parallel Interfacing Converter

针对传统的并联接口变换器控制策略存在功率分配精度低、惯性小以及循环功率等问题,提出了交直流混合微电网并联接口变换器的虚拟同步发电机(VSG)控制策略。将小交流电压信号源注入到直流子网的DC/DC转换器中,使直流子网的功率-电压下垂控制变为功率-频率下垂控制。将原本采集的局部母线直流电压变为全局直流叠加频率,从而将直流子网的叠加频率与虚拟同步机的虚拟频率差值作为VSG的机械力矩。通过与传统控制策略的仿真结果比对分析,验证了所提方法的有效性和优越性。

Aiming at the problems of low power distribution accuracy,small inertia and circulating power in the traditional control strategy of parallel interfacing converter,a virtual synchronous generator(VSG)control strategy for AC/DC hybrid microgrid parallel interfacing converter is proposed.A small AC voltage signal source is injected into the DC/DC converter of the DC subgrid,and the power-voltage droop control is changed into the power-frequency droop control.Then,the local bus DC voltage collected originally is changed into global DC superimposed frequency,and the difference between the superimposed frequency of DC subgrid and the virtual frequency of VSG is taken as the mechanical torque of VSG.By comparing the simulation results with the traditional control strategy,the effectiveness and superiority of the proposed method are verified.