Workflow enables fast, cost-effective simulation of electric drives

December 13, 2013 // By Christoph Hammerschmidt
In response to the rising demand of the automotive industry for electric powertrains, the FZI research centre in Karlsruhe (Germany) has launched the SimCelerate research project to develop methodologies for the real-time simulation of electric motors. The workflow developed by the institute significantly simplifies and accelerates existing approaches.

Along with partner companies ITI GmbH and SET Power Systems GmbH, the Karlsruhe researchers created an automated design flow that enables transforming of simulations based on the model description language Modelica to the hardware description language VHDL. This approach enables real-time simulation of physical models of power train components to Field-programmable Gate Arrays (FPGAs). A specific model library developed for the Modelica tool SimulationX enables generating synthesisable FPGA designs, in particular for modelling electro motors. The design flow is crafted such that this technology is accessible also for users without specific FPGA expertise.

Hardware-in-the-loop (HiL) techniques and associated test methodologies are used in many industries in development, optimisation and test of technical systems and components. Applying this technique in emulating electric motors along with electronic controllers and power electronic components however demands tough real-time capabilities with very short cycle times; simulation steps in the microsecond range are required.

Typically, these computations cannot be done by microprocessor because of these tough timing requirements. For this reasons, the researchers executed the model computations on FPGAs. The problem: The description language used to control FPGAs is not capable of executing non-causal models such as differential equations. The widespread transfer of such models to FPGAs by means of manual coding is difficult, complex and prone to error. The results of the SimCelerate project greatly simplify this workflow. An automated workflow, it significantly, the effort and susceptibility to errors of the present practice of manually coding differential equations describing the behaviour of electric motors are significantly reduced. This translates into better quality of the simulations and into significantly lower cost, the institute claims.

ITI GmbH contributed its real-time approach to the project. ITI is the vendor of the SimulationX engineering tool. SET Power Systems added its experience in simulating electromotors. The FZI Forschungszentrum Informatik developed methods to transfer Modelica models into optimized VHDL code.

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