储能双向DC/DC变换器自适应充放电无缝切换策略

Seamless switching strategy of adaptive charge and discharge for bidirectional DC/DC converter with storage energy

为提高直流微电网内储能单元的动态性能与抗干扰能力,文中提出了一种针对储能双向DC/DC变换器的充放电无缝切换控制策略。该策略根据母线电压高低进行储能单元自适应充放电切换,进而保持母线电压稳定。在此基础上,考虑到双向DC/DC变换器的非线性特征,引入了可通过fal函数在线调节误差反馈系数的非线性无缝电流环,实现了储能双向DC/DC变换器的充放电无缝切换,提高了控制策略的动态性能与鲁棒性。通过仿真和实验验证了该策略的可行性与有效性,在母线电压跌落、陡升与系统参数变化等工况下,均可实现储能单元的充放电无缝切换。

To improve the dynamic performance and anti-jamming capability of the energy storage unit in DC micro-grid, a seamless switching control strategy for bidirectional DC/DC converter with energy storage is presented in this paper. According to the change of DC bus voltage, the adaptive switching between charging and discharging of energy storage unit can be realized to keep the bus voltage stable. On this basis, taking into account the nonlinear characteristics of the bidirectional DC/DC converter, a nonlinear seamless current inner loop is introduced into the controller. The nonlinear fal function is used to adjust the error feedback coefficient online, which improves the dynamic performance and the robustness of the control strategy. As a result, the charging/discharging seamless switching of the energy storage bidirectional DC/DC converter is realized. The feasibility and validity of the proposed strategy are verified by simulation and experiment. Seamless switching of charging and discharging of energy storage unit can be achieved under bus voltage drop, steep rise and system parameter change conditions.