# Dynamic Energy Efficient Control of Induction Machines Using Anticipative Flux Templates
## 9 Conclusions  
The objective of this paper was to increase the energy efficiency of induction machines in dynamic operation. The optimization procedure considers the system dynamics given by the state equations of an induction machine, the main induction saturation effect, as well as the voltage and current limits. The procedure minimizes the losses given by a power loss model, as well as the speed error. The optimization results show that in order to decrease the losses, an anticipative flux increase to the torque step is beneficial. To reduce the computation effort, a template is derived that resembles the shape of this anticipatory flux trajectory. This step is necessary, because the optimization procedure is a very time-consuming numerical optimization. A template can be stored in a lookup table and only needs to be adapted to fit the current driving situation, which can be done online with little computation effort. The template based solution was further enhanced by developing a template adaptation method. Using this method, any given speed trajectory and not just speed ramps can be processed. The speed trajectory was delayed by the amount of the anticipation time, to give time to modify the flux prior to the torque trajectory in order to obtain an improved energy efficiency. Although this delay may not be acceptable in every application, it will be feasible in many industrial and electric mobility applications, e.g., in manufacturing processes, where torque and speed values can be predicted to some extent, or in electric vehicles, where a small acceleration delay is already common for turbocharged combustion engines and will most likely also be accepted in order to increase the driving range. For an application in autonomous driving vehicles, the load and speed profile also will be typically known in advance due to the path planning algorithms. For periods of steady state operation, the optimal steady state flux is automatically applied by the template generation. The template generation and anticipation time were verified by a simulation study. Measurement results proved the increased energy efficiency, when using the offline optimization procedure, as well as the template based solution. A comparison to a model predictive numerical online solution was given, which also leads to the conclusion that the modification of the flux trajectory in an anticipative manner is beneficial to minimizing the power losses in transient states, thus improving the energy efficiency of the system. Finally, the benefit of the template based solution was illustrated by applying the template and the template adaptation method to the WLTP driving cycle to prove its superiority against less optimized systems in a standardized and comparable real-world scenario. Figure 19: Simulation of saved energy using the template adaptation algorithm with the WLTP cycle. The developed optimization methods can be further improved by taking into account the iron losses in the machine model and optimization procedure. Further testing and measurements, especially on larger machines, are necessary to refine the details of the template based solution's implementation. Finally, this solution has to be implemented in a real-world industrial or electric vehicle application. Conceptualization, G.S. ; methodology, A.D. and M.W. ; software, A.D. and M.W. ; validation, A.D. and M.W. ; investigation, A.D.; writing--original draft preparation, M.W. ; writing--review and editing, G.S. and M.W. ; visualization, A.D. and M.W. ; supervision, G.S. ; project administration, G.S. ; funding acquisition, G.S. All authors have read and agreed to the published version of the manuscript. This project \"EffiDynA\" was funded by the operational program Innovation and Energy Revolution. Funded by the European Union, the European Fund for regional development, and the federal state of Baden-Wurttemberg, Germany. The authors declare no conflict of interest.