Embedded Web Server

Master Thesis at the Polytechnic University of Catalonia.
Design and implementation of an HMI on an embedded PC based on a Qt application and a web page for a voltage sags emulator

The CITCEA-UPC (Centre d’Innovació Tecnològica en Convertidors Estàtics i Accionaments – Universitat Politècnica de Catalunya) is part of the Technical University of Catalonia (UPC BarcelonaTech) and is specialized in all types of applications requiring the control of energy and/or movement. They respond to the needs of enterprises and develop prototypes for a great number of industrial sectors. One of these prototypes is a voltage sags emulator simulating the behaviour of a microgrid with any kind of local load connected. The emulator is connected to an embedded PC through a controller area network (CAN bus), which acts as a human-machine-interface and allows the configuration of the inverter via a touch panel.

A new HMI, including a possibility to securely configure the emulator from remote devices, had to be designed and implemented within the scope of this thesis. For this purpose, a suitable client-server architecture had to be chosen. It was found that the web client architecture provides the most benefits, and so further investigation had to be done on bi-directional communications on the web. Finally, the proposed HMI had to be implemented. The application controls the emulator through the CAN bus and includes a web server capable of the WebSocket protocol. This allows the user to control the emulator remotely through a secured web page, and due to the WebSocket protocol, parameters of the emulator (like frequencies, currents or voltages) can be transmitted to the web client in real-time. At the moment, the emulator can be operated in two different modes, both needing different user interfaces. In future, additional modes will be introduced, therefore another criteria was to write the application in a way that it can be easily extended.

ClientPolytechnic University of CataloniaServicesEmbedded web server, CAN bus, WebSocket, C++, QtYear2015Linkgriesser.io