When operated in generator mode, ZF's ZF-TERRA+ serves as a power source for electric loads. The company says that up to 5% in fuel savings can be achieved through power-on-demand operation of electrified auxiliaries on an agricultural tractor.
CO2 emissions can also be reduced together with a boosted productivity and tractive effort. The ZF-TERRA+ system can be operated permanently in a generator mode to provide, depending on the size of the electric machine, up to 50 or 70 kW.
If applied as power source to electric drives on an implement, the ZF-TERRA+ system can yield fuel savings and increased available power up to 5-10% on the tractor through better efficiency when compared to conventional hydraulic drives.
As a plus, the electrification on the implement enables new design concepts on the implement through its flexibility in the arrangement and installation of drives. For agricultural implements ZF also supplies solutions for electric drives with appropriate gearbox combinations.
If extended by an energy storage unit such as a hybrid battery, the ZF-TERRA+ system can be converted to a parallel mild hybrid system. Such an extension enables typical hybrid functions such as stop/start with powered auxiliaries, short term boost of the engine, and stabilization and smoothing of engine operation.
Particularly for intelligent power management of vehicle auxiliaries and electric drives on an implement, the extension of the generator system to a hybrid system creates additional degrees of freedom, which can be utilized for further improvements in fuel consumption, exhaust emissions, and performance.
ZF-TERRA+ is integrated into the transmission and has, depending on the application, a neutral installation space. This enables easy integration of a separating clutch to decouple the generator/hybrid module from the engine for extended functionalities such as utilized in a full hybrid. Furthermore, an easy integration of a planetary gearset for increased power output is thus also possible.
For manufacturers of agricultural machinery, ZF supplies complete and single-source solutions for electrification systems. This also comprises, apart from single components, power management control. This control optimizes the integrated operation of generator, combustion engine, and electric auxiliaries in such a way as to avoid operational states of the powertrain with low efficiency and high exhaust emissions.
Optimal matching of transmission shift or control strategy and power management, as provided by ZF, is a core competence in the market of electrified drivetrains. The strategy has direct influence on the actual savings and efficiency of the electrified drivetrain. ZF can draw on its longtime experience with vehicle drivetrain control on tractors as well as experience coming from passenger and commercial vehicles hybrid projects.
ZF says it PTO-generator is a suitable add-on solution. It can be mounted to the front or rear hitch and also enables the mounting of the PTO-generator on the same side as the implement. This is advantageous if an implement has to be mounted to the rear hitch in addition to the PTO-generator and in addition to a further implement at the front hitch.
The PTO-generator has a compact design and contains all the necessary components of a full-fledged generator system. Besides the power electronics for the generator, the system comprises a high voltage dc-link and power electronics for controlled ac outputs and a dc/dc converter for provision of 12- or 24-V dc with high power. The compact generator provides 50-kW continuous power, which can be supplied to the implement depending on the requirements via a high voltage dc-interface or two frequency-controlled 400-V ac-interfaces.
When using the frequency-controlled interfaces, two electric drives on the implement with up to 25 kW power each can be dynamically and precisely controlled to their target speed. This enables drive tasks to be performed not only in a more efficient but also faster and more precise way. On the other hand, this permits a more precise dosing of seed or fertilizer and hence cost savings over conventionally driven implements.
On top of that, the PTO-generator provides a powerful 12- and 24-V dc-interface for supply of electric dc loads on the implement. Thus, power-consuming lighting concepts can be implemented. The cooling system of the generator and power electronics is self-contained, avoiding the need for a supply of coolant from tractor or implement.
With all those features, the PTO-generator from ZF provides a powerful generator system that is easy to mount and enables a quick entrance into the world of electrified implements without additional efforts.