Research on Energy Management of Fuel-Cell Electric Tractor Based on Quadratic Utility Function

AbstractTo solve the problems of high pollutant emission of traditional diesel tractors and short continuous operation time of pure electric tractors, a new tractor powertrain system model with a fuel cell as the primary energy source, battery as the auxiliary energy source, and electric motors as the power source is developed. The fuel cell, battery, and degradation models are constructed. A rule-based control strategy is designed to distribute the current between fuel cell and battery, maximizing the benefits of the fuel cell and battery in the energy management process by differentiating the quadratic utility function and combining the Karush-Kuhn-Tucker (KKT) conditions. Finally, the optimal weight coefficient in the strategy is obtained through the Nash equilibrium. The simulation results show that the designed energy management strategy can adequately maintain the battery state of charge (SOC), reduce the performance degradation of the fuel cell, and improve the tractor’s ploughing mileage. The tractor is equipped with 960 g of hydrogen, the initial SOC is 90%, and it can operate continuously for 2.8 h.