New vehicle control strategy for fuel consumption and battery state of health improvement in a series hybrid vehicle utilizing fuzzy logic

Series hybrid vehicles have become increasingly popular due to their lower environmental impacts. However, the efficiency of a series hybrid electric vehicle largely depends on its control strategy. This paper presents a practical control strategy that optimizes the performance of series hybrid vehicle in terms of fuel consumption. To achieve this objective, the power-follower strategy, which uses a fuzzy controller, is employed. The combination of the fuzzy controller and the optimal working method for the combustion engine improves the fuel consumption and battery’s state of health. It should be stated that the GT-Power model is validated via several experiments. Three control strategies including thermostat, power-follower, and Max-SOC, are simulated and compared to evaluate the fuel efficiency of the vehicle model. The power-follower strategy led to a 3.7% and 60.1% reduction in fuel consumption compared to the thermostat strategy (currently implemented as the RUNNA strategy) and the Max-SOC strategy, respectively. Moreover, by using the power-follower method instead of a thermostat, frequent charging and discharging of the battery is prevented, which is beneficial for improving the battery’s state of charge.