Over the course of two days, Steven B. Leeb, Professor in the Department of Electrical Engineering and Computer Science at the Massachusetts Institute of Technology (MIT), shared with students and faculty from the Department of Electrical and Computer Engineering at Técnico the applications of power electronics. His talks focused on the development of systems with electrical actuators, sensors and power electronics, with industrial, medical and power quality applications, including non-intrusive load monitoring (NILM).

On January 28, during the DEEC TALK Multi-Use Power Electronics, Steven B. Leeb presented his research, sharing insights into the development process of the vibration monitoring system VAMPIRE (“Vibration Assessment Monitoring Point with Integrated Recovery of Energy”).

He began by highlighting the need to create systems capable of operating under critical conditions, emphasizing the role of the Internet of Things and the processing of data collected by different types of sensors. In this context, the researcher drew attention to a factor common to many machines: vibration.
“The reason why I look at vibration is that it is a very interesting problem. A lot of money is spent on vibration measurements,” he noted.

These measurements can be carried out, for example, in systems that include motors, such as those used on ships, in order to detect operational faults. “There is a strong correlation between the vibration of one component and the induced behaviour of another component in the equipment, and when systems become more complex it can be difficult to interpret what is happening,” he explained. For this reason, he emphasized the importance of performing measurements at multiple points in the system over time.

However, for continuous monitoring, the various sensors placed on different electrical cables within the system require a power supply, which can be provided through energy harvesting. In this way, the sensors take advantage of the energy generated by the magnetic field created by the electric current flowing through the wire on which they are installed, and transmit data wirelessly (such as via Bluetooth or Wi-Fi) to the user.

In this system, the sensors do not require batteries. Instead, switches are used to control the flow of current from capacitors (where energy is stored) to the rest of the system, according to the most appropriate time window, contributing to greater efficiency.

The researcher concluded his presentation with a brief reflection on the importance of developing these devices for monitoring anomalies in the operation of various systems, including domestic applications, as well as for analysing their possible causes.

The session also included several questions from the researchers in attendance.

On the following day, Steven B. Leeb led a workshop in which he challenged several students of Electrical and Computer Engineering and Electronic Engineering to build a system integrating a speed controller for a small motor, taking into account factors such as energy control and desired power output.

The researcher began by addressing the problem from a theoretical perspective, mathematically demonstrating the electrical variations in the circuit caused by the introduction of different components, such as switches and resistors, using the operation of a common electric stove as an example. Throughout the session, he also answered several questions from the students.

After the lecture, participants moved to the laboratory, where they had direct contact with the practical component. Schematic guides and materials were provided, encouraging students to build and test their own circuits with the support of the researcher.

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