Pietro Tosato

Street lighting in smart cities: A simulation tool for the design of systems based on narrowband PLC

Excessive or improper street lighting is currently responsible for a significant waste of electrical energy in many cities worldwide. In order to improve energy efficiency, the traditional light posts are expected to be gradually replaced by smart systems able to adapt the features of the emitted light to different environmental, traffic, or crowdedness conditions. Power Line Communication (PLC) is the natural choice to support smart light control, since no additional communication infrastructure is needed. However, at the moment not so many simulation tools exist to guide the design and the deployment of smart lighting systems based on PLC. In this paper, we partially address this issue by presenting suitable circuit models that can be used to analyze (through simulations at the physical layer) the behavior of narrowband PLC (NB-PLC) signals transmitted over low-voltage (LV) lines for street light control. The proposed approach is quite simple from the computational point of view, and it is scalable enough to evaluate the quality of PLC signals in large networks with different topologies. The results of several simulations, with signals in the frequency range 95-148.5 kHz, have been compared with the outcomes of some laboratory experiments over a test line.

Long range wireless sensing powered by plant-microbial fuel cell

Going low power and having a low or neutral impact on the environment is key for embedded systems, as pervasive and wearable consumer electronics is growing. In this paper, we present a self-sustaining, ultra-low power device, supplied by a Plant-Microbial Fuel Cell (PMFC) and capable of smart sensing and long-range communication. The use of a PMFC as a power source is challenging but has many advantages like the only requirement of watering the plant. The system uses aggressive power management thanks to FRAM technology exploited to retain microcontroller status and to shutdown electronics without losing context information. Experimental results show that the proposed system paves the way to energy neutral sensors powered by biosystems available almost anywhere on Earth.

Microbial fuel cell as a biosensor and a power source for flora health monitoring

Microbial Fuel Cells are a promising technology for many different applications like wastewater treatment and energy supply system for monitoring hostile environments. In this article, we discuss and analyze the possibility to use jointly a small scale MFC as an energy source and a biosensor to monitor the health of the plants, with an embedded wireless sensor node. We present the prototype of the MFC and the embedded system powered by the electric energy generated by bacteria. The rate of energy generation is used as a feedback on plants health state. Finally, we demonstrate that the amount of scavenged energy is sufficient to power on even some external sensors embedded in the wireless node.

Design and implementation of zero power wake-up for PLC modems in smart street lighting systems

Power line communication is becoming important as a leading technology in Smart Grid applications. This paper presents a new system to reduce the power consumption of the power line modems, implementing a zero-power stand-by feature. The incoming wake-up signal is as simple as a PLC frame and its associated energy is used to supply the wake-up logic. The system is mainly conceived for street lighting systems that use power line communication and where the stand-by power represents an issue because there are thousands of lamps in a city, and the total power consumption of the modems in stand-by mode is not negligible. This paper presents the architecture of the system, as well as the design choices. Experimental results of the system applied to a street light network show that it is possible to wake-up selectively a cluster of lamps up to a distance of about 250m.

Design optimization of zero power wake-up receiver in Power line communication

One of the main challenges of the smart grid applications is relying on efficient communication infrastructure and service. Important applications, such as smart lighting, use Power line communication (PLC) on the pre-existing infrastructure. Nevertheless, this protocol is not energy efficient when communication is sporadic. In this paper, we propose a method to eliminate the energy consumption in street lights during the stand-by mode. The proposed wake-up system permits to avoid waste of energy of the PLC modem when communication is not present on the line. Experimental results compare different design choices to achieve an optimized design.

Implementation of phasor measurement units on low-cost embedded platforms: A feasibility study

The Phasor Measurement Units (PMUs) are currently considered among the most useful instruments for smart grid monitoring. While the traditional PMUs deployed at the transmission level are usually high-performance and expensive instruments, the interest in smaller and cheaper units able to perform synchronized measurements of voltage and current waveforms at the distribution level is currently growing. In this paper, a feasibility study about the implementation of state-of-the-art estimation algorithms for PMUs in low-cost embedded platforms is presented. The proposed approach relies on an Interpolated Discrete Fourier Transform (IpDFT) for static frequency offset estimation followed by a modified Taylor-Fourier Transform (TFT) for waveform amplitude, phase, frequency and rate of change of frequency (ROCOF) estimation under dynamic conditions. Both algorithms, implemented in C++, run on a Beagle-Bone Black board. After evaluating the total computation time as a function of both the sampling rate and the number of observed cycles, a criterion to choose the data acquisition stage is described. Finally, the accuracy of synchrophasor, frequency and ROCOF estimators is determined by emulating most of the testing conditions reported in the IEEE Standards C37.118.1-2011 and C37.118.1a-2014.

Zero-energy wake up for power line communications in smart cities

Street lighting is responsible for 6% of the greenhouse global gases emissions and for 19% of the total use of electrical energy; nevertheless it is essential for citizens safety in streets. The migration to smart lighting introduces the problem of power consumption of the intelligent infrastructure in standby mode, which was not present in classic lighting. In this paper, we show how to eliminate the power consumption in listening mode with power line communication (PLC) infrastructure, adding zero-power wakeup receivers to the modems. This promising solution can be extended as a general technology for monitoring and controlling in a smart grid distribution. We show the design of the different hardware sections and, supported by simulations and experimental results, we discuss some considerations about the most efficient configurations and the best routing to wake up a remote PLC modem with the minimum power.

An optimized wind energy harvester for remote pollution monitoring

We present the design optimization of an energy harvesting device based on the aeroelastic flutter effect, developed for converting wind energy in electrical energy. Due to the aeroelastic mechanical principle, the energy harvester can be equipped with a system capable to follow the Maximum Power Point of the wind generator and then to sustain the energy demand of a sensor system used for pollution monitoring. The aeroelastic harvester consists of a tensioned ribbon coupled with an electromagnetic transducer and a power conditioning unit to guarantee the power supply for remote sensors deployed in hard-to-reach areas. This paper presents the characterization of the wind flutter generator and the design of a Maximum Power Point Tracking (MPPT) logic that controls the tension of the belt for the maximum energy extraction.

Energy neutral design of an IoT system for pollution monitoring

A lot of research and studies have shown the impact of pollution on health, and a lot of regulation are in action in the European Union and other countries around the world defining the allowed concentration levels of volatile chemicals. Standard measurements equipment are very expensive, and static large stations require space and high power consumption, thus are not suitable to realize portable equipment nor to seamlessly be integrated in Smart Cities. In this paper we present the design and evaluation of a portable pollution monitoring equipment as small as 20×15×5 cm, powered by mini PV arrays, embedding particulate matter and CO/VOCs sensors for air quality estimation. A LoRa radio transceiver completes the set of peripherals. Finally, energy budget analysis shows that neutral operations can be achieved enabling a “deploy and forget” paradigm suitable for the IoT.

Plug into a Plant: Using a Plant Microbial Fuel Cell and a Wake-Up Radio for an Energy Neutral Sensing System

As a step toward sustainable wireless sensing, we present a proof of concept system that uses a Plant Microbial Fuel Cells (PMFC) as a power source. To match the very low power production capabilities of the PMFC, we couple it with an ultra-low power wake-up receiver used as a trigger for sampling and transmission of the sensed value. We demonstrate that this combination, with a new, receiver initiated MAC-level communication protocol, results in a sustainable system for reasonable data rates, shown to be 30s in our laboratory setting. This work offers the first steps toward large-scale wireless sensor networks in applications where the sensors are surrounded by living plants that can provide a green and perpetual power supply.