Hybrid Real-Time Embedded Controller Concept for Power Electronics Applications

This paper will present a hybrid concept for enabling non real time operating systems to control real time tasks without modifying the operating system itself. As an example an embedded controller with a non real time flavor of the LINUX operation system is used to generate a pulse width modulated signal with a maximum switching frequency of up to 32MHz while the clock frequency of the controller is only 16MHz. In the paper the theoretical concepts will be explained in detail combined with practical results and analysis of the resulting timing properties. Comparisons will be made between a completely controller based realization of the problem given and the FPGA version An FPGA is employed to provide all the real time capabilities needed at frequencies exceeding the clock frequency of the controller. The possible application in this example could be the control of power electronics for driving electrical drives or switching power supplies. As the total cost of the used hard- and software is below 200, the proposed concept in its current configuration is also suitable for teaching and demonstrating students the control and concepts of modern system integration in the realm of power electronics and electrical drives.