Development of a Real-time Framework between MATLAB and PLC through OPC-UA: A case study of a microgrid energy management system

Abstract

Many research laboratories, which develop advanced algorithms for controlling Renewable Energy Systems (RES), lack specialized equipment to carry out research activities and perform experiments. Real-time simulation platforms are suitable for designing specific applications such as fast or real-time computation models. In addition, these platforms provide fast, accurate and reliable studies for RES control implementation. However, Real-time platforms are too expensive and not affordable for most laboratories. In this context, a cost-effective platform is designed to assist researchers in their activities. The hardware solution consists of using a Programmable Logic Control (PLC) to acquire data from the various sensors and control the system through actuators and PID controllers. From a software standpoint, a communication framework between MATLAB and the PLC is developed using the OPC-UA (Open Platform Communications Unified Architecture) technology. In this paper, the operation and efficiency of the platform have been tested using the Software in the Loop (SIL) technique. Hence, the operating model is designed using MATLAB/Simulink to simulate and analyze the appropriate control technique suitable for PLC implementation, whereas the control is executed through Siemens S7-1200 PLC using TIA PORTAL. A visualization interface is set up using WinCC-RT. Furthermore, this paper describes the design of the platform and discusses its utilization, providing examples of its usage through a case study. Indeed, a complex algorithm developed in MATLAB/Simulink can be automatically executed by any PLC using the designed framework.