具有同步发电机特性的储能型光伏并网发电系统研究

Research on grid-connected photovoltaics-energy storage system with synchronous generator characteristics

基于虚拟同步发电机(virtual synchronous generator,VSG)控制的并网逆变器可以对电网的频率和电压起到一定的支撑作用.但是,仅由光伏供电的逆变器难以模拟同步发电机的特性.本文提出一种具有同步发电机特性的储能型光伏并网发电系统,并给出了相应的VSG控制策略、DC–DC控制策略以及协调控制方法;建立了系统的小信号模型,分析了参数取值对动态性能和稳定性的影响.仿真结果不但表明该系统具有同步发电机特性,可实现光伏阵列的最大功率跟踪(maximum power point tracking,MPPT)和储能的充放电控制;而且验证了理论分析的正确性.

The Grid-connected inverter based on virtual synchronous generator(VSG)has capacity to support the frequency and voltage of electric power system.However,it is difficult to simulate the characteristics of synchronous generators for inverters only powered photovoltaics(PV).This paper proposed a grid-connected PV-energy storage system which mimics the characteristics of synchronous generator,and presented control tactics,including VSG control strategy,DC–DC control strategy and coordinated control strategy.A small signal model was established in order to analyze effects of the parameters on dynamic performance and stability.The simulation results not only indicated that the system has the characteristics of synchronous generator,track maximum power point of the PV cells and control charge and discharge of the energy storage flexibly;but also verify the correctness of the theoretical analysis.