具有有功功率自备用能力的光伏系统虚拟同步控制研究

Study on PV system virtual synchronization control with active power self-reserve ability

虚拟同步机技术以模拟传统同步发电机组机电暂态特性的控制方式,使光伏并网逆变器具有同步机组的惯量、阻尼、频率和电压调整等运行外特性.然而传统光伏虚拟同步技术需要依靠外加储能系统,才能实现虚拟同步动态响应,这将大幅增加光伏并网系统的建设成本.针对此问题,提出一种降功率虚拟同步控制策略,利用光伏出力的非线性特点,通过适当降低光伏电源的有功输出,使光伏系统自身具备有功功率的上调能力,从而在不外加储能单元的情况下能够自主参与电网频率响应.仿真分析结果验证了所提控制策略的有效性和正确性,可以为今后光伏并网消纳提供理论依据.

The virtual synchronous machine technology simulates the electromechanical transient characteristics of the traditional synchronous generator set,which makes the photovoltaic grid connected inverter have the inertia,damping,frequency and voltage adjustment of the synchronous unit.However,over-reliance on energy storage systems will inevitably affect traditional PV virtual synchronization technology applications in actual engineering,which will greatly increase the construction cost of PV system.In this paper,a reduced power virtual synchronous control strategy is proposed.By properly reducing the active power output of photovoltaic power supply making use of non-linear property of PV system output,the PV system can actively participate in the frequency response of power grid without additional energy storage unit.The simulation results verify the effectiveness and correctness of the proposed control strategy,which can provide a theoretical basis for large-scale PV connection and consumption.