电容电流模式Buck变换器的开环控制特性的动力学研究

Dynamical Investigation for Open-loop Control Property of Capacitor Current Mode Buck Converter

电容电流反馈控制是一种新颖的控制技术,尚未有文献开展电容电流模式开关功率变换器的开环控制特性动力学研究。通过对三种开关状态的描述和不同开关状态内的时域求解,建立了电容电流模式Buck变换器的具有两条切换边界的二维精确离散时间模型。利用分岔图和最大Lyapunov指数谱等分析方法,揭示了负载电阻变化时电容电流模式Buck变换器的开环动力学行为。结果说明:在不同的负载电阻下,该变换器运行在正常的周期振荡、非正常的次谐波振荡即混沌等状态,尤其在部分负载电阻时,电容电流模式控制器失控,输出电压不能正常调节。此外,建立了PSIM电路仿真模型,并研制了相应的硬件电路。仿真和实验捕捉的时域波形和相轨图有效地验证了理论分析的正确性。

Capacitor current feedback control is a novel control technique.However,no literature performs the dynamical investigations on the open-loop control properties of capacitor current mode switching power converters.Through the descriptions of three switch states and the time-domain solutions in different switch states,a two-dimensionally accurate discrete-time model of the capacitor current mode buck converter with two switched boundaries is established.By utilizing the dynamical analysis approaches,such as bifurcation diagrams and maximum Lyapunov exponent spectrum,dynamical behaviors of the capacitor current mode buck converter with the variation of load resistance are investigated.The results illustrate that under different load resistances this converter works in normally periodic oscillations,abnormally sub-harmonic oscillations,i e,chaos,and so on.Especially at partial load resistances,the capacitor current mode controller is out of control,leading to that the output voltage cannot be regulated.Furthermore,PSIM circuit simulation model is established and the corresponding hardware circuit is developed,upon which the time-domain waveforms and phase portraits captured by simulations and experiments validate the correctness of theoretical analyses effectively.