考虑多储能系统功率分配的独立直流微电网协调控制策略

针对多源储结构的独立直流微电网,提出考虑多储能系统功率分配的独立直流微电网协调控制策略,以实现源储能源利用率最大化与多储能系统间功率合理分配两方面的平衡控制,提升微网持续供电能力。根据直流母线电压信号将微网系统运行划分为5种工作模式,以协调源储运行,保证光伏能源利用率最大化及储能系统出力充足。同时,直流微电网工作模式切换过程中源储控制器保持不变,并根据当前运行状态自动调节自身运行曲线,维持系统功率平衡和母线电压稳定。其中,基于自适应功率控制的光伏系统控制方法根据母线电压自动调节光伏系统运行点追踪或偏离最大功率点,实现最大功率点跟踪(maximum power point tracking ,MPPT)模式与降功率模式间的平滑切换。其次,基于荷电状态(state of charge,SOC)的自适应功率下垂控制器根据储能单元自身SOC调节其下垂曲线,实现系统功率在多储能单元间的动态分配,避免过充过放。最后,通过搭建Matlab /Simulink 仿真模型,验证了所提方法的有效性。

Coordinated Control for Islanded DC Microgrid Considering Power Sharing of Multiple Energy Storages

A coordinated control for islanded DC microgrid considering power sharing of multiple energy storages is proposed to realize the balance control of the energy utilization maximization and the reasonable power sharing among multiple energy storages. The operation of the DC Microgrid is divided into five working modes according to the DC bus voltage. During mode transition, control structure of each unit keeps unchanged, and its droop curve can be adjusted adaptively according to current operating state. The coordinated operation of source and storage maintains the system power balance and bus voltage stability, which maximize the utilization rate of photovoltaic energy and ensures sufficient output of energy storage. Firstly, an adaptive power control strategy is applied to PV converters, which is based on automatic regulate the output power of PV tracking or off the maximum power point according to the DC bus voltage and realizes the smooth switching between maximum power point tracking (MPPT) mode and off-MPPT mode. Secondly, an adaptive droop control strategy based on the state of charge is designed for energy storages, which realizes the reasonable distribution of system power by multiple energy storage units according to their SOC and avoids excessive discharge or depth charge. Finally, the control strategy is verified by simulation with Matlab/Simulink.