滞环电流模式控制uk变换器的非线性现象研究

NONLINEAR PHENOMENA IN HYSTERISTIC CURRENT-CONTROLLED UK CONVERTERS

根据滑模变结构系统的原理,对滞环电流模式控制?uk 变换器的运行状态进行了研究。推导出在切换面上的等效控制,并导出了切换面上滑模运动的状态方程,以此状态方程为基础,可由特征值法来判断平衡点的稳定性。由特征值的数值计算结果证明,当参考电流增加时平衡点的失稳过程是超临界霍普分叉过程,各电路参数对参考电流的分叉点有重要影响。此外,数值仿真和电路实验均表明,滞环电流模式控制 ?uk 变换器的动态行为十分复杂,除周期态和极限环外,还可能产生准周期和混沌状态。这研究方法还可以推广到其它滑模控制非线性系统的研究中去。

The operation states of hysteretic current controlled ?uk converter are studied based on the theory o variable structure system. The equivalent control on th switching surface of the converter is derived, thus concludes th sliding-mode equation on the switching surface. Based on thi equation, the stability of equilibrium point is studied with th calculation of eigenvalues, and it can be proved that supercritical Hopf bifurcation will occur when the referenc current increases. Other circuit parameters will make influenc on the bifurcation point of current reference. Furthermore, wit numerical simulation and experimental circuit implementation the converter shows complex operation states, it can produc not only period 1 and limit cycle, but also quasiperiodicity an chaos. The method in our study can also be extended to othe sliding mode controlled nonlinear systems.