Power sources coordination through multivariable linear parameter-varying/ H_{infty }H∞H∞ control with application to multi-source electric vehicles

摘要

In this study, the problem of multi-source power sharing strategy within electric vehicles is considered. Three different kinds of power sources - fuel cell, battery and supercapacitor - compose the power supply system, where all sources are current-controlled and paralleled together with their associated DC-DC converters on a common DC link. The DC-link voltage must be regulated regardless of load variations corresponding to the driving cycle. The proposed strategy is a robust control solution using a multiple-input multiple-output linear parameter-varying (LPV)/ H∞; controller which provides the three current references with respect to source frequency characteristics. The selection of the weighting functions is guided by a genetic algorithm whose optimisation criterion expresses the frequency separation requirements. A reduced-order version of the LPV / H∞ controller is also proposed to handle an embedded implementation with limited computational burden. The non-linear multi-source system is simulated in MATLAB ®/Simulink ® using two different types of driving cycles: the driving cycle of IFSTTAR (Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux) and a constant load profile used in order to illustrate system steady-state behaviour. Simulation results show good performance in supplying the load at constant DC-link voltage according to user-configured frequency-separation power sharing strategy. When assessed against the classical-proportional-integral-based filtering strategy taken as base-line, the proposed strategy offers the possibility of integrating a variety of constraints into a systematic design procedure, whose result guarantees stability and performance robustness.