新型零电压全桥DC-DC变换器的仿真建模

零电压全桥(ZVS-FB)PWM DC-DC变换器基本模型电路在连续导电模式(CCM)和不连续导电模式(DCM)之间不能有很平滑的过渡,而且既不能用在瞬时分析中,也不能用在稳态的分析中.为了克服基本模型以上的这些局限性,文中通过对ZVS-FB-PWM变换器的状态变量变化快慢进行分类,分析独立平均状态变量,在基本平均模型的基础上提出了一种新的DCM和CCM工作模式的平均等效模型.通过仿真可以得出,新平均模型很接近开关模型中相对应参数的动态平均值,且在CCM和DCM工作模式转换的过渡的瞬间有一个精密的轨迹特性.新模型可以在工作点处线性化得到小信号模型,而小信号模型又很接近原始系统的规律,可以为控制的设计提供可靠的起始点.仿真结果验证了该建模方法的正确性.

Modeling of a Novel ZVS -FB -PWM DC -DC Converter

Basic averaged model of ZVS - FB - PWM converter could not make a smooth transition between CCM and DCM operation. And it cannot be used either for transient or stability analysis. To overcome these limitations of basic model, this paper analyses independent average state variable by classifying state variables changing speed, and then introduces a new average model for both DCM and CCM mode of operation developed based on the basic one. The simulation result shows that the parameters of new model approximate dynamic average, and there is a very close tracking characteristics for transitions between CCM and DCM operating models. The new models can be linearized at an operating point to derive a small - signal model that closely approximates the behavior around an orbit for the original system. , hence, providing a solid starting point for control design. The simulation results verified that the modeling approach is reasonable.