由于可再生能源的间歇性特点,储能单元广泛应用于孤岛直流微电网中.为保护储能单元,防止过度充放,需要对储能单元的荷电状态(state of charge,SOC)实行均衡控制,然而各储能单元线路阻抗及容量存在的差异将对SOC 均衡造成影响.针对这一问题,提出了一种基于一致性算法及自适应下垂控制的储能单元 SOC 均衡控制策略.首先,通过定义电流比例系数,建立了各储能单元下垂系数与SOC之间的函数关系式,实现了储能单元自适应SOC均衡,并通过劳斯判据证明了系统的稳定性.其次,将所提控制策略与其他文献控制方法进行对比,并且考虑了 4 种不同工况对SOC均衡的影响.最后,通过Matlab/Simulink进行了仿真分析,验证了所提控制策略的有效性.
Adaptive SOC equalization of an islanded DC microgrid considering line impedance and energy storage capacity
Because of the intermittent nature of renewable energy sources,energy storage units are widely used in islanded DC microgrids.To protect the energy storage units and prevent overcharging or deep discharging,it is necessary to implement balanced control of the state of charge(SOC)of the units.However,the differences in line impedance and capacity of each energy storage unit will affect the balance of the SOC.To address this issue,a SOC balancing control strategy for energy storage units based on a consensus algorithm and adaptive droop control is proposed.First,by defining the current proportional coefficients,a functional relationship between the droop coefficients of each energy storage unit and the SOC is established,achieving adaptive SOC balance of the energy storage units.The stability of the system is proved by the Routh criterion.Secondly,the proposed control strategy is compared with other control methods in the literature,and the impact of four different working conditions on SOC balance is considered.Finally,simulation analysis is carried out using Matlab/Simulink,verifying the effectiveness of the proposed control strategy.
DC microgriddroop controlconsensus algorithmSOC balance
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维普
