- مبلغ: ۸۶,۰۰۰ تومان
- مبلغ: ۹۱,۰۰۰ تومان
The nonlinearity of the switching process in DC-DC converters can result in the inaccuracy and invalidation of traditional stability criterion based on linear modeling, which is very harmful in practice, especially for the DC-DC converters with high stability requirements. In this paper, the describing function method is adopted for the modeling of switching process, namely, pulse width modulation (PWM), in DCDC converters, and the describing function of PWM is derived in detail. Considering the nonlinear items in the obtained describing function of PWM, the selection of the parameters in these nonlinear items are firstly provided and proved in this paper. With the obtained describing function, the stability of PWM DC-DC converter can be analyzed exactly. Taken a PWM boost converter as an example, the nonlinear model based on describing function and the linear model are established, respectively, further, the stability analysis based on these two kinds of models are carried out. Comparing with the traditional linear stability criterion, the simulation and experimental results validate the effectiveness and accuracy of the stability analysis based on describing function method. Further, the transition interval of the PWM DC-DC converter from stable region to unstable region can be determined exactly by the proposed stability analysis method, which is helpful to determine the stability margin in real engineering applications. Therefore, this paper provides a practical stability analysis method for PWM DC-DC converters.
In this paper, the describing function of PWM switching process has been derived, comparing with the traditional linear modeling and stability analysis method, the critical range of the DC-DC converter system has been extended to a curve, instead of a point (-1/K, j0). The transition interval from stable range to unstable range can be determined exactly by the proposed stability analysis method, which is very helpful for determining the stability margin in real engineering applications. The simulation and experimental results validate the effectiveness and accuracy of the stability analysis based on describing method. Therefore, this paper gives a new choice for the stability analysis of PWM DC-DC converters.