Dynamics analysis of the hybrid powertrain under multi-frequency excitations with two time scales

Abstract

Aiming at the dynamic behavior of hybrid powertrain under multi-frequency excitations with two time scales, this paper has carried out related research work. A nonlinear dynamic model of hybrid powertrain is established by taking engine excitation, load excitation and electromagnetic excitation into consideration. Considering the order gap between the excitation frequency and the natural frequency, slow variables are introduced to transform this model into a fast-slow model. Through introducing the De Moivre equation, slow variables are unified into a single one. The dynamic equations under different excitation frequencies and amplitudes are obtained. Bifurcation theory is applied to study the bifurcation behavior when the equilibrium point is unstable, and the conditions for the generation of fold bifurcation are derived. By means of numerical analysis, the influence of excitation frequency and amplitude on dynamics behavior is investigated by curve of equilibrium point, transformed phase portrait and time history. The simulation results show that fold bifurcation may lead to jumping phenomenon of the system trajectory and bursting oscillation is generated correspondingly. Additionally, the bifurcation characteristics of the hybrid powertrain may change with the excitation frequency and amplitude, making the pattern of bursting oscillation more complicated. The conclusion provides a reference for further analysis of dynamic behavior of hybrid powertrain.

A New Availability Assessment Method for Complex Control Systems With Multi-Characteristics

“…c) Obtain A * S,i , which is a sample of the system availability, by quantitative analysis of the GO method as follows: The signal flows 1,4,7,8,15,19,20,25,29,47,60,70,71,72, 74 and 116 are shared signal flows in Appendix III, and thus the new exact GO algorithm with shared signals proposed in Section II-A-2 is adopted to operate the quantitative analysis. Because the success probability of the shared signal flow 19 is 1 and the shared signal flow 1, 7 and 60 are the one-order minimum cut sets and the input operators, the success probability of the system corresponding to these state combinations of shared signals will be 0. where A * [m * ] is the lower confidence limit of the system availability of the system at the 0.95 confidence level.…”

“…Given these obvious advantages, this paper first proposes a new availability assessment method for complex control systems with multi-characteristics based on the GO method. For complex control system, some properties containing stability, parametric optimization, and reliability analysis have been concerned [29]- [37], but this paper also aims to fill the gap in availability assessment methods for these types of complex control systems. The main contributions of this study are as follows:…”

Research on operating domain optimization of power split hybrid electric vehicle based on global bifurcation and chaos threshold

“…With the continuous power and speed improvements, the electromechanical coupling effect became more and more prominent. 4 Zhou et al studied the nonlinear dynamic characteristics of a system under the internal and external excitations were studied. The effects of the speed and load fluctuations on the system dynamic response were analyzed.…”