基于精确反馈线性化的直流微电网双向直流变换器反步滑模控制

摘要

The variation of the bus voltage in the DC micro network has a great influence on the load. In the process of regulating the DC bus voltage by the energy storage system through the bi-directional DC converter, the duty cycle will change by a wide margin, which leads to serious nonlinear problem and unstable bus voltage. To solve the problems, backstepping sliding mode variable structure control is combined with exact feedback linearization, which is applied to the bi-directional DC-DC converter. The non-minimum phase characteristics and variable structure features of the converter are solved. The method can guarantee the robustness and stability of the system under uncertain and nonlinear conditions and external disturbances. The converter state equation is analyzed firstly, and the exact feedback linearization model through coordinate transformation is deduced and then the backstepping sliding mode controller is designed. Finally, the results of simulation built by PSCAD demonstrate the validity and superiority of the proposed control scheme.%直流微网中母线电压的变化对负载有很大的影响.储能系统通过双向直流变换器调节直流母线电压的过程中,占空比会大幅度变化,使变换器呈现严重的非线性,导致母线电压不稳定.针对这一问题,将精确反馈线性化与反步滑模控制相结合应用于双向直流变换器中,解决了变换器的非最小相位特性和变结构特性,保证了系统在不确定性和非线性条件下、外界干扰情况下的鲁棒性和稳定性.首先分析了变换器的状态方程,通过坐标变换推导出精确反馈线性化模型,并在此模型上设计了反步滑模控制器.最后利用PSCAD软件进行仿真,验证了所提控制方法的有效性及优越性.