New development method of control software for smart energy applications dealing with multi-sample-rate controllers

In a smart energy system, power converters should be controlled by complex control software. However the efficient development of reliable control software is difficult. We have proposed to introduce a “model-based design” process using MATLAB/Simulink, established in the automotive and aerospace fields, to the development of power electronics systems. However, it was difficult in the past because calculating switching circuit as the plant model is difficult in MATLAB/Simulink due to the socalled stiff equation problem. Thus, in this study, we have developed a simulation environment in which the standard model-based design tool, MATLAB/Simulink, and the simulation engine for power switching circuits, SCALE, work cooperatively. SCALE was originally developed to solve stiff equation and efficiently simulate power switching circuits. This software environment enables us to design control algorithms with intuitive block diagram expression and test them in actual hardware, without writing a C program. Furthermore to improve this environment, a mechanism that handles the multiple sample rates was introduced. Smart energy systems that use several controllers with different sampling rates can be simulated in the proposed environment. Thus, we can develop control software for smart energy systems in a timely and cost effective manner.