An improved logic threshold approach of energy management for a power-split hybrid electric vehicle

The power-split hybrid electric vehicle (HEV) has the unique advantages of the series and parallel types of HEV power train configurations. However, it needs a sophisticated control system to manage the power-split HEV power trains. To simplify control strategy and improve fuel-saving capability, we design an improved logic threshold approach of energy management for a power-split HEV assisted by an integrated starter generator (ISG). The improved logic threshold controller manages the ICE within its peak-efficiency region at first. Then the electrical power demand is established based on the ICE energy output. On that premise, a variable logic threshold value is defined to achieve the power distribution between the ISG and the electric motor/generator (EMG). Finally, simulation models for the power-split HEV with improved logic threshold controller are established in ADVISOR. The ICE, EMG and ISG operating performances of power-split HEV are performed under two driving cycles. The comprehensive results show that battery power consumption reduces up to 8%, the ICE efficiency improves up to 1.7%, the motor driving system efficiency improves up to 6.1% of a power-split HEV with the improved logic threshold approach compared with one with the logic threshold approach.