DCM模式BUCK变换器的建模与混沌控制

Modeling and Chaos Control of Buck Converter in DCM

为进一步探索开关变换器的非线性特性和混沌控制方法,对电流断续导通工况下的BUCK变换器进行了研究。通过MATLAB建模仿真,分别研究了电流断续导通模式BUCK变换器工作状态与输入电压Vi、电容C和电感L3种电路参数的影响关系。在选定条件下改变3种电路参数,均观察到了系统从单周期稳定态到倍周期分岔,再到混沌的演化过程。仿真结果表明3种电路参数对系统状态的影响方式互不相同,且相较于电流连续导通模式,断续导通模式具有更复杂的变化规律。在此基础上采用一种混沌控制策略,实现了对断续导通模式BUCK变换器的混沌控制。该控制策略快速有效,仅需0.6μs就可以将系统从混沌态控制到稳定态。此外,该控制策略不需要设定预期的目标轨道,不依赖变换器自身电路参数,仅需调整一个外部可调参数,在验证仿真模型正确的同时也提供了一种有效的混沌控制方法。

To further explore the nonlinear characteristic and the chaos control method of the switching converter,the buck converter running in discontinuous conduction mode(DCM)is studied.By modeling and simulation based on MATLAB,the effects on the circuit status are investigated for three circuit parameters:input voltage Vi,capacitance C and inductance L.Under the selected conditions,the transformation of converter from steady-state to bifurcate to chaotic is observed by changing three circuit parameters.The simulation results show that three circuit parameters affect the system in different ways.Compared to continuous conduction mode,the discontinuous conduction mode shows more complicated change rules.Based on the model,a chaos control strategy is used to suppress chaotic motions in the voltage control buck converter running in discontinuous conduction mode.The chaos control strategy is fast and effective.It only takes 0.6μs to control the system from chaos to stability.Besides,the chaos control strategy doesn't need to set a predetermined trajectory.It just needs to adjust one external parameter,and it is independent of internal circuit parameters.Thus,the correctness of the model is verified and an effective chaos control method is provided.