Energy Management Strategy for Oscillating Drivetrains Equipped with an Electric Variable Transmission Srajan Goyal DecisionS Flanders Make Lommel, Belgium srajan.goyal@flandersmake.be Florian Verbelen Department of Electrical Energy, Metals, Mechanical Constructions and Systems, Ghent University Ghent, Belgium florian.verbelen@ugent.be Ahmed A-E. Abdallh MotionS Flanders Make Leuven, Belgium ahmed.abdallh@flandersmake.be Kurt Stockman Department of Electrical Energy, Metals, Mechanical Constructions and Systems, Ghent University Ghent, Belgium kurt.stockman@ugent.be Peter Sergeant Department of Electrical Energy, Metals, Mechanical Constructions and Systems, Ghent University Ghent, Belgium peter.sergeant@ugent.be Abstract—In this study the dynamic capability of the Electric Variable Transmission (EVT) is presented based on the tracking of a highly dynamic oscillating load. The targeted applications are 3-phase grid connected machines with periodic motions at high frequencies (> 5) Hz, which result in a high alternating to average power ratio (> 5). The overall consumed grid energy is minimized by a high-level non-parametric cascaded control to recuperate the oscillating load energy in a mechanical energy storage component. Here in this paper, this oscillating energy is stored in the inner rotor of the EVT, thereby making EVT an energy storing device in itself. The drivetrain containing an EVT is also shown to have a good load speed tracking performance with the maximum error of ±1%. Index Terms—Cascaded control, dynamic modeling, electric variable transmission, energy minimization, oscillating drive- trains. I. I NTRODUCTION An Electric Variable Transmission (EVT), also called dual mechanical port electric machine, is a competitive alternative power split device that combines the functionality of two electrical machines and a planetary gear set into one single electromechanical device [1]. It is also shown in the same paper that an EVT can significantly reduce the fuel con- sumption in a Hybrid Electric Vehicle (HEV). However, due to the relatively modest dynamic requirements in automotive applications, the dynamic capabilities of the EVT are not fully utilized. To the best of authors’ knowledge, the dynamic behavior of the EVT has not been fully investigated yet. This aspect has been covered in this paper by utilizing the dynamic behavior of the considered EVT by driving high frequency oscillating loads. One of the most important grid connected industrial dy- namic applications are production machines with fast recipro- cating loads (> 5) Hz, e.g. weaving looms and plate punching machines. The subsequent acceleration and deceleration gives rise to a reciprocating energy flow which is converted back and forth between the electrical and mechanical components. Compared to the slow energy storage of elevators and cranes, these kind of applications exhibit a much higher power to energy ratio. In order to recuperate this energy, either a fully controlled Active Front End (AFE) or a Passive Front End (PFE) with an electric energy storage device, e.g. capacitor bank, can be used [2]. Another way to recover this recipro- cating energy is by using a mechanical flywheel, attached to the shaft of a traditional motor, where the recovered energy can be reciprocated back during acceleration of the load. The main issue with this solution is that the flywheel needs to be accelerated or decelerated during start up and shut down. As start-up times are crucial in industrial machines (delays are not allowed or should be minimized), higher torque values during start-up are required. This often results in the necessity of a larger electric machine, i.e. oversized motor, to drive the application. As a consequence, this electric motor will only be used efficiently during start-up. For the remaining normal operation, the motor is used in partial load which is highly inefficient. Alternatively, an EVT can be used instead of the motor. Thanks to the EVT unique configuration, the flywheel is mechanically disconnected from the load, hence fast start-up and stop processes are possible. Also, higher speed variations are possible with a flywheel providing more flexibility in terms of energy transfer. In order to optimize the energy drawn from the grid, the overall system needs to be controlled, via a proper energy management strategy, in concurrent with the EVT current con- trol. The energy management problem for dynamic machines is non-convex, highly nonlinear mainly due to the nonlinear behavior of various electric components and electro-magnetic