一种新的PWM DC—DC变换器建模方法

介绍一种带变压隔离器，含多个功率开关器件的PWM变换器工作在连续状态的建模方法。该方法考虑了变换器的寄生元件，由理想功率开关管、理想二极管和理想变压器组成的理想开关部分用受控电流源和电压源替代。基于能量守恒原理，给出了确定寄生电阻、二极管正向压降的等效值的方法。为了简化模型，建立了将平均寄生元件转移到电感支路中的映射规则。文中阐述了以PWM推挽变换器为例的建模过程，得到了PWM推挽变换器工作在连续状态的动态大信号、DC及小信号模型，并进行了计算机仿真分析，结果令人满意。该建模方法的优点是模型由标准电路元件组成，因而可以直接用于通用电路仿真程序，对于更复杂的变换器拓扑尤为方便。

A New Method for Modeling PWM DC-DC Converters

A new method is introduced for modeling PWM DC-DC converter wit h multi-switches and transformers, which operate in continuous conduction mode, including parasitic components. The ideal switching part consisted of ideal swi tches, ideal diodes, and an ideal transformer is modeled by dependent c urrent and voltage sources. A method is presented for determining equivalent ave raged values of parasitic resistances and parasitic offset voltages, based on th e principle of energy conservation. To simplify the obtained circuit models of t he PWM converter, a reflection rule is developed which allows for shifting the averaged parasitic components to the inductor branch. As an example, a procedure for mo-deling the PWM push-pull converter is presented. Dynamic large signal, dc and small-signal circuit mo-dels of PWM push-pull converter are derived . It satisfies the simulated models. The models consisted o f standard circuit elements, therefore, they can be directly used in simulation programs standard circuit, and the method can be particularly convenient in the case of more complex converter topologies.