Bilinear system model of DC-DC converters is built,combined with the control objective and extending the system,closed-loop nonlinear control system model of DC-DC converters is found.

• 首先建立了DC-DC变换器双线性系统数学模型,结合控制目的进行适当变形,得到DC-DC变换器的闭环非线性控制系统模型。