Determination and Application of Maximum Efficiency Curve of Crawler Electric Tractor Motors

Abstract

With the excessive use of fossil fuels such as oil, the energy crisis and environmental pollution have become important problems related to people’s livelihoods. In agriculture, as a new type of green agricultural machinery, the electric tractor has the advantages of high energy utilization and no exhaust emission. The motor is the core component of an electric tractor’s drive system. Its characteristics and control directly affect a tractor’s operating efficiency, operating quality, and energy consumption. A motor drive control scheme based on a characteristic curve at the maximum efficiency of an electric motor was adopted to address the problems of low motor power utilization and short continuous operation time on a full charge in electric tractors. By leveraging methods to obtain characteristic curves at the lowest fuel consumption for gasoline engines, we determined the characteristic curve at the maximum efficiency for a motor in a crawler-type electric tractor. Plowing is the most basic form of tractor operation, and it represents the agricultural work that accounts for most of a tractor’s use. A field test was conducted on the drive control in plowing operation based on the curve, and the energy consumed to plow each m2, continuous plowing operation time on a full charge, and operating efficiency were tested. The test results showed plowing power consumption per m2 of about 8.40 × 10−3 kWh and work efficiency of 707.07 m2/h. Compared with the traditional tractor, the cost of plowing 1 m2 by the crawler-type electric tractor was reduced by 20.3%–32.5%. Because the control improves operating efficiency, battery energy consumption is reduced and continuous operation time is extended; hence, the control achieves its purpose.