Research on economical mode switching control strategy of dual-motor four-wheel drive considering motor drag and mode switching transient loss

Abstract

In existing research on economical-performance control strategies for 4WD EV, only vehicle control strategies obtained through static efficiency interpolation of the electric-drive-system are considered, without considering the influence of high-frequency mode switching on energy consumption, and the difference between the actual power loss of the motor step-torque transient response and the theoretical loss calculated by steady-state map interpolation in the mode switching process. The research presents an economical mode switching control strategy that considers the step-torque transient response power loss caused by motor drag and mode switching. An electric-drive-system torque response testing platform was built to study the influence of the actual power loss of the motor step-torque transient response on energy consumption during mode switching under transient conditions. A mode boundary division method was proposed to analyze how different mode division impact on energy consumption and mode switching frequency so as to find the relationship between different operating points and mode boundary areas, and the optimal mode boundary width in each characteristic range was optimized hierarchically to realize reduction in energy consumption by 3.37% and reduction in mode switching frequency by 63.13%. Among them, the optimal mode boundary width accounts for 83.33% of the vehicle energy consumption reduction rate.