Research on Global Optimal Energy Management Strategy of Agricultural Hybrid Tractor Equipped with CVT

Abstract

This paper presents a proposed global optimal energy management strategy based on dynamic programming to enhance the energy consumption efficiency of an agricultural hybrid tractor that is equipped with a continuously variable transmission (CVT). Firstly, using a diesel-electric parallel agricultural hybrid tractor as the research object, a tractor-rotary tillage coupling dynamics model is constructed. Secondly, with the torque and speed of the motor, the torque and speed of the diesel engine, and the CVT speed ratio as the control variables, the state of charge (SOC) of the power battery as the state variable, and the goal of minimizing the total energy consumption of the whole machine, a global optimal energy management model based on dynamic programming is established. Finally, the field operation measured data is injected into the MATLAB simulation model, and experiments are carried out to verify the effectiveness of the energy management strategy. The results show that compared with the power-following energy management strategy, the proposed energy management strategy can make the diesel engine and electric motor work in the optimal area, and effectively reduce the total cost of energy consumption of the tractor during field operations. Under the condition of rotary tillage, the total cost of energy consumption is decreased by 16.89%.

Trends and Future Perspective of Electrification in Agricultural Tractor-Implement Applications

“…The hybrid mode was characterized by submodes, namely, full ICE, battery charge, and power boost, which were selected according to the required power and the battery SOC. Zhang et al [67] considered a parallel hybrid powertrain with a CVT downstream the coupling of the ICE and the electric motor. The authors compared, through simulations based on real data collected in the field during a rotary tillage operation, a global optimization strategy, based on DP, with an RBS power follower strategy, with the aim of minimizing the total cost of energy consumption.…”

“…Nowadays, power-split architectures on tractors are realized mainly through hydrostatic transmissions to change the power characteristics before recombining the power flows alongside the transmission. However, electric machines and modern power electronics can improve power-split configurations like the one described in Figure 6b [64][65][66][67][68]. The configuration may seem very similar to a series architecture.…”

Research on Control Strategy of APSO-Optimized Fuzzy PID for Series Hybrid Tractors

“…T end = 0.9T max (7) where v t ideal is the ideal velocity of the particle at iteration t times; v start is the initial velocity of the particle's ideal velocity; and x min and x max are the upper and lower limits of the decision variable, respectively. T end is the number of iterations in the cosine-varying stage of the ideal velocity, and T max is the maximum number of iterations.…”

“…Energy management strategy (EMS) is a core aspect of studying hybrid tractor systems and is crucial for achieving efficient energy utilization and power optimization [5,6]. Currently, there are two main types of energy management strategies proposed for hybrid tractors: rule-based and optimization-based methods [7][8][9]. Of these, rule-based methods are extensively employed in hybrid vehicles due to the advantages of simplicity and reliability [10,11].…”

Application and Efficiency of a Series-Hybrid Drive for Agricultural Use Based on a Modified Version of the World Harmonized Transient Cycle

“…Additionally, by altering the transmission of an off-road heavy-duty vehicle, its efficiency can be increased. It is hypothesized that a CVT can be replaced by highly effective electric motors [17,[38][39][40][41][42][43][44][45][46][47], thus achieving similar transmission effectiveness while reducing the number of parts that cause mechanical losses. In this study, a power-splitting method for a series-hybrid system is investigated.…”