Electrification of tractors as a farm equipment may be tougher than electrifying cars and commercial vehicles. However, it is likely to become a reality, writes Bhushan Mhapralkar.
Unlike passenger cars or trucks, tractors have several different standardised interfaces coupled with a wide variety of attachments, which supply them with energy. The attached tools are supplied simultaneously from the tractor with mechanical, hydraulic and electrical energy so far based on the commonly used 12 V power port. Agco/Fendt recently built a research tractor to study an additional power transmission in the higher voltage and power range, which is using a 700 V DC bus voltage level to carry up to 130 kW of electrical power. Electric farm vehicles are clearly gaining renewed interest in the agriculture industry. Diesel-electric systems in farm tractors, sprayers and implements may not be far from being available. With a flywheel-mounted generator, which is used to produce electric current as the prime mover, it displaces the traditional hydraulic pumps and gear sets.
The advantages of electrification of electric platforms include provision of an alternate power source to PTO and SCV couplers. Electric platforms can even improve some agricultural processes. For example, the ability to transfer power electrically eliminates the presence of oil, significantly minimising the risk of contamination for the product being handled.
Some of the state-of-the-art electrified platforms already on the scene include John Deere 7030 Series E-Premium tractor, the Agco RoGator E sprayer, the Belarus Tractor International 3023 tractor, and the Rauch EDR fertiliser spreader. These vehicles provide a glimpse into the potential future of this technology. Taking over the functions of traditional mechanical and hydraulic linkages, pumps and gear sets, electrified platforms allow for more control over tractor components such as the coolant pump and fan at speeds that are independent of the engine speed. The best advantage of electrification lies not just in higher operational efficiency, but in fuel savings of up to 13 per cent. The John Deere 7530 Premium tractor pulling a power harrow is known to deliver a fuel saving of up to 13 per cent. Pulling a trailer, the tractor is known to deliver a fuel saving of up to 9.3 per cent. On an average, tractors like the 7530 E-Premium are said to offer a five per cent fuel saving over conventional tractors.
Supplying complete electrification systems for agriculture machinery manufacturers is based on the new generator module ZF-TERRA+ in combination with the power electronics. ZF sources opine that up to five per cent savings in consumption can be achieved on the tractor through power-on-demand operation of electrical auxiliaries apart from boosting productivity and tractive effort, as well as reduced CO2 emissions. Depending on the machine size, ZF-TERRA+ integrated generator solution can provide up to 70 kW electric power. ZF also offers an extension by a control unit for intelligent energy and hybrid management. The interaction of generator, internal combustion engine and electric drives on vehicle and implement is matched to avoid vehicle conditions with poor efficiency, thus achieving best operational performance. The ideal coordination of transmission and energy management as offered by ZF is a key competence on the market of electrified drivelines. It has direct influence on the actual savings potential and economic efficiency. In this respect, ZF relies on its long-term experience in tractor vehicle management and its broad expertise in commercial vehicle and passenger car hybrid projects.
The PTO generator from ZF is the ideal add-on solution. Easy to retrofit and compact, the generator provides 50 kW continuous power, which depending on the electrified implement, can be supplied via a high-voltage DC interface or two frequency-controlled 400 V AC interfaces. When using the frequency-controlled interfaces, two drives with up to 25 kW power each can be operated on the implement and precisely controlled to their target speed. Consequently, drive tasks on the implement are performed in a more efficient, faster and precise way. This allows, for example, precision-dosing of seed or fertiliser, hence cost savings versus conventionally driven implements.
In the case of the Rauch EDR fertiliser spreader, the implement working speed is not dependent on the tractor driveline speed. This can optimise fertiliser delivery rate and cut fuel use because the engine can be operated at maximum efficiency. Electrification also can make fertiliser application more precise because the discs can be controlled independently. For example, at the edge of a field, one disc can be turned off to minimise product waste.
On an average, tractors like the 7530 E-Premium are said to offer a five per cent fuel saving over conventional tractors.
Depending on the machine size, ZF-TERRA+ integrated generator solution can provide up to 70 kW electric power.