Control of electric drive powertrain based on variable speed control in construction machinery

To improve the efficiency of construction machinery driven by pure electric power and to reduce energy con-sumption, a variable-pressure differential control strategy based on variable-speed control for a quantitative pump load-sensing system is proposed. The scheme of quantitative pump load sensing system based on variable speed control is introduced. The advantages, control objectives, and control strategies of the proposed control system are analyzed in different working conditions using simulations and experiments. The results show that the proposed variable-pressure differential control strategy can substantially reduce energy consumption. In the no-load mode, the power consumption of the proposed system was approximately 33.3% lower than that of the traditional system. During the idle mode, the proposed system consumed no energy, while the traditional system consumed about 0.6 kW. The energy saving of the main pump in the low-speed and low-flow-rate case was about 38%. In the lifting and pressure-holding case, the motor of the proposed system consumed 17.3% less power than that of the traditional system. In all test conditions, the proposed system demonstrated a good energy-saving ability. In addition, the proposed system has a high response rate and smooth operation across different working conditions, which demonstrates good control performance.