基于储能优化及荷电状态均衡的直流微电网控制研究

Research on DC microgrid control based on energy storage optimization and state of charge equilibrium

为了实现直流微电网中储能设备的优化控制以及荷电状态均衡控制,提出了一种基于储能优化及荷电状态均衡的直流微电网控制策略。分析了直流微电网结构和储能模型,利用模拟电机特性结合电压电流双闭环PI控制方法优化储能设备控制,通过模拟电机特性结合下垂系数控制法达到荷电状态均衡控制,并搭建Simulink仿真模型进行验证。由仿真结果可知:在风力输出功率和光伏输出功率波动时,在模拟直流电机特性的储能装置控制优化策略下,蓄电池能够有效抑制母线电压波动,维持系统各部分功率平衡;在蓄电池充电、放电及充放电过程中,在模拟电机特性与下垂系数控制下,让荷电状态高的蓄电池输出较多功率,而荷电状态低的蓄电池则吸收较多功率,最终实现并联蓄电池荷电状态的平衡。研究结果表明,该方法能有效抑制母线电压跌落,增强直流母线的稳定性。

In order to realize the optimal control of energy storage equipment and state of charge equilibrium control in DC microgrid,a DC microgrid control strategy based on energy storage optimization and state of charge equilibrium is proposed.The DC microgrid structure and energy storage model are analyzed.The control of energy storage equipment is optimized by using the simulated motor characteristics combined with the voltage and current double closed-loop PI control method.The state of charge equilibrium control is achieved by simulating the motor characteristics combined with the droop coefficient control method,and the Simulink simulation model is built for verification.The simulation results show that when the wind output power and photovoltaic output power fluctuate,under the control optimization strategy of energy storage device based on the characteristics of simulated DC motor,the battery can effectively suppress the bus voltage fluctuation and maintain the power balance of each part of the system.In the process of battery charging,discharging and charging and discharging,under the control of analog motor characteristics and sag coefficient,the battery with high state of charge can output more power,while the battery with low state of charge can absorb more power,and finally realize the balance of state of charge of parallel batteries.The results show that this method can effectively suppress the bus voltage drop and enhance the stability of DC bus.