级联H桥储能系统均衡系数能量均衡策略

Energy Equilibrium Strategy with Equilibrium Coefficient for Cascaded H-bridge Energy Storage System

级联H桥储能系统作为解决新能源发电系统输出能量波动性、间歇性问题的有效手段,在实际使用中直流侧储能单元容易出现能量不均衡的情况,从而严重影响储能系统运行的稳定性。依据储能单元差异化充放电的思想,提出了均衡系数能量均衡算法。通过该算法输出A、B、C三相及相内各功率模块的均衡系数,将均衡系数作用于系统的调制波,通过对调制波进行调整,进而使得各储能单元以不同的速度存释能量,最终达到能量均衡的状态。仿真和实验结果表明,所提出的能量均衡控制策略能够有效地实现各相及相内各功率模块储能单元的能量均衡,而且动态性能好,均衡速度快。

A cascaded H-bridge energy storage system is an effective means to solve the problems of volatility and intermittence of output energy from new energy power generation systems. In its practical applications,the DC-side energy storage unit is prone to energy imbalance,which seriously affects the stability of the energy storage system. Based on the idea of differential charging and discharging of energy storage units,an energy equilibrium algorithm with equilibrium coefficient is proposed in this paper. This algorithm outputs the equilibrium coefficients in phases A,B,and C and those of intra-phase power modules,which are applied in the modulated wave of the system to make the corresponding adjustments. As a result,each energy storage unit can release energy at different speeds. Finally,the state of energy equilibrium is reached. Simulation and experimental results show that the proposed energy strategy can effectively achieve energy equilibrium among the energy storage unit in each phase and each intra-phase power module. In addition,it has a satisfying dynamic performance and a fast equilibrium speed.