考虑功率最大输出与储能协调的光储VSG控制策略

VSG control strategy for a photovoltaic system with storage considering maximum power output and energy storage coordination

在传统虚拟同步发电机(virtual synchronous generator, VSG)控制的光储系统中,电池通过频繁充放电处理波动的光伏功率,易出现早衰问题。为优化电池运行,提出一种考虑功率最大输出与储能协调的光储VSG控制策略。首先,建立输出频率与直流侧电容电压偏差的比例关系,实现光伏功率的最大输出与VSG的惯性支撑。其次,利用下垂特性控制电池功率输出,在实现系统一次调频功能的基础上提升电池能量管理的灵活度。然后,设计一种稳定直流侧电压的分段控制方案,确保系统正常工作时直流侧电压在合理范围之内。最后,通过仿真实验验证所提方法不仅保留了VSG的惯性支撑和一次调频功能,还实现了光伏功率的最大输出,减少了对电池的依赖。

In the traditional photovoltaic storage virtual synchronous generator(VSG)system,the battery handles the fluctuation of photovoltaic power by frequent charging and discharging.This leads to premature battery failure.To optimize battery operation,a VSG control strategy for a photovoltaic system with storage considering maximum power output and energy storage coordination is proposed.First,the proportional correlation between output frequency and DC side voltage deviation is established to realize maximum output of PV power and the inertia support of the VSG.Secondly,the sagging characteristic is used to control the battery power output to enhance the flexibility of battery energy management and this can realize the primary frequency regulation function of the system.Thirdly,a segmented control scheme to stabilize the DC side voltage is designed to ensure that the DC side voltage of the system is within a reasonable range when the system is working normally.Finally,simulation experiments verify that the proposed method not only retains the inertia support and primary frequency regulation functions of VSG control,but also realizes the maximization of PV power output and reduces the dependence on batteries.This work is supported by the National Natural Science Foundation of China(No.52177100).