基于两级全钒液流电池的风电储能系统的功率优化分配控制

为更好地利用储能系统平抑风电功率波动,采用了两级全钒液流电池(VRB)储能的功率优化分配及控制策略。基于直驱型永磁同步风电系统的工作原理及系统变流器的控制策略,建立了全钒液流电池等效电路模型,采用基于VRB组荷电状态(SOC)的双模式切换的双闭环控制策略,通过比较每级电池组荷电状态值确定优选目标,以VRB组最大充放电功率为电池组安全充放电的约束条件,提出两级VRB组的功率优化分配控制策略,利用Matlab/Simulink仿真平台,在变风速条件下对不同荷电状态的两级VRB储能系统平抑风电功率波动进行仿真,并与功率平均分配策略作对比。结果表明,两级VRB储能系统功率优化分配控制策略能有效平抑风电机组功率波动,同时,还确保了电池组工作于安全运行区域,有效地减少了VRB组的充放电次数,延长了电池组的寿命。

Power Optimization Distribution and Control of Energy Storage System for Wind Power Generation Based on Two-stage Vanadium Redox Flow Battery

In order to make better use of storage system to smooth the fluctuation of wind power generation, this paper proposed the optimization power distribution control strategies of two-stage VRB storage. Firstly, the operating principle of directly-driven permanent magnet synchronous generation (PMSG) wind power and the control strategies of the system were analyzed. Secondly, the equivalent circuit of VRB was established, and by using the interface of the double bi-directional DC/DC converter a double closed loop control strategy of DC/DC converter was established to switch charge-discharge style as a constraint of the state of charge (SOC) of VRB. Thirdly, by taking the SOC value of each VRB as priority target selection and using the maximum charge and discharge power as the constraint conditions, the optimization power distribution control strategies of two-stage VRB storage were proposed. Finally, using two-stage VRB storage system with different SOC values to smooth wind power fluctuation under the wind speed variation was simulated with the Matlab/Simulink, and the simulation results were compared by using the average distribution strategy of active power. The simulation results show that the proposed control strategy can not only smooth wind power fluctuation, but also ensure the battery work in the safe operation region, and could reduce the discharging and charging times of VRB, which can prolong battery life.