Abstract: Nonlinear PID control methodwas introduced into DC-DC converters, thusmaking the converters be of strong robustness, adaptability and stability , andovercoming the sensibility to the parameter variation of controlled systemswhen the conventional PID control method is used .In this paper , with the Buck-Boost converter as an example , the simulation model with nonlinear PID control was proposed.The effects of the variations of the input voltage , the load resistance and the inner parameters on the output voltage were respectively simulated and analyzed.The simulation results show that the application of nonlinear PID control to the Buck-Boost converter can make the converter more adaptable to the outer and inner parameter variations.Moreover , this control method can also be applied to other types of DC-DC converters.

Key words: nonlinear PID, DC-DC converter, parameter variation