Abstract:

For the problem that oxygen starvation and pressure fluctuation affect dynamic performance and service life of vehicular fuel cells system， in this paper， a cooperative control strategy of air system air mass flow and pressure based on oxygen excess ratio compensation is proposed. Firstly， a 120 kW model of vehicular fuel cells air system is established， with its parameters determined by bench experiments， and the transfer function model fitted according to the experimental data. Secondly， the cathode pressure of the stack is indirectly obtained based on the extended state observer， and the feedforward + PI is used to establish a cascade control model of the outer oxygen excess ratio in cascade control to correct the target flow. Furthermore， the inverted decoupling and active disturbance rejection controller are used to decouple the airflow and pressure from the inner loop control， and the total disturbance composed with the model uncertainty and external disturbance is estimated and compensated. Simulation and experimental studies show that the proposed cascade control strategy based on oxygen excess ratio compensation can quickly track the oxygen excess ratio， increase the stack power and accurately control the pressure， which proves the cooperativity and robustness of the strategy. It helps to improve the dynamic performance of the vehicular fuel cell system and extend its service life.

Key words: vehicular fuel cell system, air supply system, inverted decoupling, active disturbance rejection control