22 is now increasingly popular, was in its infancy and the fact that most available parts were based on 400 V architecture pushed the design in that direction. Pfaff explains: “There are clear advantages in the 800 V systems, two of the main ones being smaller cables that are easier to manage and less copper, which makes it less expensive. But when we started working on this, the 400 V platform that brought EVs to the masses came with validation, testing and availability, so we picked something in between. “As a result of that, the operating range of the system is between 400 V and 465 V, just above what is used in most of the current automotive vehicles. As we go into the future, we really feel, like everybody else, that it’s going up to the higher voltage system. Our system is capable of that, but right now it is in that middle ground.” One of the keys to the vehicle’s success was switching the operational functions from hydraulic to electric. To achieve this, the team opted for a motor and ball-screw linear actuator, which converts rotary movement into linear movement, and this was a method they had prior experience with, albeit in a much smaller form. As a result, the vehicle has a total of six motors to power its drive, lift and tilt functions. Two permanent magnet brushless A/C motors are used to drive the tracks in tandem, while the remaining four motors are DC servo devices; two powering the lift arm and two operating the tilt, which then connects to attachments such as a mower, planer, bucket or pallet forks. Each of the six motors is controlled by its own independent controller, with all six controllers governed by a master computer, which is connected to the joysticks in the machine. The software then tunes the whole system to control those motors, both independently and, most importantly, simultaneously. “When the operator is controlling the machine, the electronic joysticks are commanding motion to those drive, lift and tilt motors,” says Pfaff. “The combination of the power going to the motor and the tuning gives the operator the correct application of that power for the work being performed. “We could have opted for a mixture of hydraulic and electric, but that didn’t make sense. How do we make a hydrostatic motor or a gear pump quieter? How could we minimise leaks? Or how do we make it give feedback to a computer so we know force and position? Some solutions exist in the marketplace, but they’re a compromise in comparison. Dossier | Bobcat T7X electric compact track loader March/April 2025 | E-Mobility Engineering Full-scale electrification means track and tool operation is all one system, providing significant functional benefits
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