PRESCRIBED-PERFORMANCE-BASED ADAPTIVE CONTROL FOR HYBRID ENERGY STORAGE SYSTEMS OF BATTERY AND SUPERCAPACITOR IN ELECTRIC VEHICLES

To achieve the desired prescribed dynamic and steady-state responses, a prescribed performance control strategy is proposed in electric vehicle system, whose power system is hybrid energy storage system (HESS). The strategy also adopts adaptive control to estimate unknown parameters. Firstly, mathematical models of HESS are derived and the unknown parameters are defined. Secondly, according to the working characteristics of energy storage units (ESUs), battery and supercapacitor are responsible for supplying power to load in different situations. Then, the performance function is considered as a prescribed range for the current tracking error and the corresponding error transformation is introduced. Meanwhile, under the projection operator adaptive law, unknown parameters can be estimated and control laws can be obtained. In addition, the whole system including models and controller is proved to be stable. Finally, simulation results show the effectiveness and superiority of the proposed control strategy.