Power system control strategy for hybrid excavator based on equivalent fuel consumption

In order to enhance fuel economy of hybrid excavator system, a control strategy based on equivalent fuel consumption is introduced. Efficiency of motor and ultra-capacitor is converted to fuel consumption of engine, which is used to establish the equivalent fuel consumption function of the whole system and further to optimize the power distribution. A compensation function is introduced to ensure the ultra-capacitor working in the safe state of charge (SOC) by the way of modifying the result of optimization. A simulation is performed and the results show that the control strategy based on equivalent fuel consumption can effectively optimize the power distribution and improve fuel economy while the SOC of ultra-capacitor is maintained at reasonable range.