Innovative Configuration Design and Experimental Evaluation of a Distributed Electric Drive System for a Hybrid Combine Harvester

Highlights An innovative series-hybrid-powered distributed electric drive configuration is proposed for the combine harvester, successfully realizing power decoupling. A DTC strategy incorporating a Luenberger Observer was designed, enabling active suppression against sudden load impacts. Quantitative validation via field harvesting tests confirmed the superiority of the proposed system configuration and control strategies. Abstract. Given the limitations of traditional combine harvesters, such as low efficiency and high emissions, this study developed a distributed electric-drive system for a hybrid combine harvester. The system employs a series hybrid configuration, where an auxiliary power unit (APU) and a power battery supply energy, while independent motors drive key modules, including the header-main shaft, threshing cylinder, cleaning fan, and unloading auger. To improve dynamic performance, a control strategy integrating direct torque control (DTC) with a Luenberger observer-based load torque feedforward compensation was implemented. An adaptive power-allocation strategy enabled the hybrid control unit (HCU) to manage APU operation based on the total power demand and battery state of charge (SOC), thereby maintaining engine operation within the high-efficiency zone. Field tests demonstrated notable performance enhancements: the threshing cylinder limited speed fluctuations to within 3% across varying feeding rates, preventing blockages; the cleaning fan maintained speed stability within 1.5%; and the header-main shaft module exhibited strong overload capacity, with only 0.44% speed variation under impact loads. Travelling speed remained stable at 3.5 to 4.5 km/h. Compared to a conventional harvester, the hybrid prototype achieved a 19.5% reduction in fuel consumption, lower grain breakage and impurity rates, and significantly decreased emissions and noise. This research validates that the proposed distributed electric drive system and control strategies improve operational quality, efficiency, and sustainability, providing a valuable reference for the green and intelligent upgrading of agricultural machinery. Keywords: Adaptive power allocation, Direct torque control, Distributed electric drive, Field testing, Series hybrid configuration.