Battery-less Energy Harvesting Research Articles

Integrating Battery-Less Energy Harvesting Devices in Multi-Hop Industrial Wireless Sensor Networks

Integrating Battery-Less Energy Harvesting Devices in Multi-Hop Industrial Wireless Sensor Networks

Enabling Low-Latency Bluetooth Low Energy on Energy Harvesting Batteryless Devices Using Wake-Up Radios.

With the growth of the number of IoT devices, the need for changing batteries is becoming cumbersome and has a significant environmental impact. Therefore, batteryless and maintenance-free IoT solutions have emerged, where energy is harvested from the ambient environment. Energy harvesting is relevant mainly for the devices that have a low energy consumption in the range of thousands of micro-watts. Bluetooth Low Energy (BLE) is one of the most popular technologies and is highly suitable for such batteryless energy harvesting devices. Specifically, the BLE friendship feature allows a Low Power Node (LPN) to sleep most of the time. An associated friend node (FN) temporarily stores the LPN’s incoming data packets. The LPN wakes up and polls periodically to its FN retrieving the stored data. Unfortunately, the LPNs typically experience high downlink (DL) latency. To resolve the latency issue, we propose combining the batteryless LPN with a secondary ultra-low-power wake-up radio (WuR), which enables it to always listen for an incoming wake-up signal (WuS). The WuR allows the FN to notify the LPN when new DL data is available by sending a WuS. This removes the need for frequent polling by the LPN, and thus saves the little valuable energy available to the batteryless LPN. In this article, we compare the standard BLE duty-cycle based polling and WuR-based data communication between an FN and a batteryless energy-harvesting LPN. This study allows optimising the LPN configuration (such as capacitor size, polling interval) based on the packet arrival rate, desired packet delivery ratio and DL latency at different harvesting powers. The result shows that WuR-based communication performs best for high harvesting power (400 W and above) and supports Poisson packet arrival rates as low as 1 s with maximum PDR using a capacitor of 50 mF or more.

Energy Savvy Network Joining Strategies for Energy Harvesting Powered TSCH Nodes

This article presents methods that enable batteryless energy harvesting powered time-synchronized channel hopping (TSCH) wireless sensor nodes to join a network with less energy wastage. Network joining of TSCH nodes is very power hungry yet inevitable process to form a working wireless sensor network (WSN). Since the energy level from energy harvesting is scarce, energy passive methods are essential. A duty-cycled network joining process in combination with an appropriate capacitor size is proposed here as they are among the factors that can be easily controlled without extra energy. When a node joins the network in a duty-cycled manner, other nodes may join the network during the gap time, which reduces energy wastage of the nodes in waiting. With an appropriate capacitor size, the capacitor can be charged up within a reasonable time and power up the node for a sufficiently long time, which increases the probability to complete the network joining process of the node. With the combination of a join duty cycle of 50% with a 100-mF capacitor, a WSN was successfully formed by two energy harvesting powered wireless sensor nodes in one network joining attempt.

Sensing, Computing, and Communications for Energy Harvesting IoTs: A Survey

With the growing number of deployments of Internet of Things (IoT) infrastructure for a wide variety of applications, the battery maintenance has become a major limitation for the sustainability of such infrastructure. To overcome this problem, energy harvesting offers a viable alternative to autonomously power IoT devices, resulting in a number of battery-less energy harvesting IoTs (or EH-IoTs) appearing in the market in recent years. Standards activities are also underway, which involve wireless protocol design suitable for EH-IoTs as well as testing procedures for various energy harvesting methods. Despite the early commercial and standards activities, IoT sensing, computing and communications under unpredictable power supply still face significant research challenges. This paper systematically surveys recent advances in EH-IoTs from several perspectives. First, it reviews the recent commercial developments for EH-IoT in terms of both products and services, followed by initial standards activities in this space. Then it surveys methods that enable the use of energy harvesting hardware as a proxy for conventional sensors to detect contexts in energy efficient manner. Next it reviews the advancements in efficient checkpointing and timekeeping for intermittently powered IoT devices. We also survey recent research in novel wireless communication techniques for EH-IoTs, such as the applications of reinforcement learning to optimize power allocations on-the-fly under unpredictable energy productions, and packet-less IoT communications and backscatter communication techniques for energy impoverished environments. The paper is concluded with a discussion of future research directions.

Design and Implementation of A Batteryless Wireless Embedded System for IoT Applications

DOI: 10.26650/electrica.2018.28092 With the increasing popularity of embedded systems that consist of identifying, sensing, processing, and communication capabilities, the Internet of Things (IoT) has enabled many new application scenarios in diverse scientific fields and provided an important opportunity to build efficient industrial systems and applications. Most embedded systems consume power provided by fixed batteries with limited capacity. However, the main disadvantage of batteries is that they must be periodically replaced with new ones or recharged when they are depleted. This kind of maintenance process increases the cost and restricts the use in inaccessible places. Considering the limitations of battery power, alternative energy sources are required for interconnected devices to operate efficiently and effectively. Harvesting or scavenging energy from the environment is an important strategy to design self-powered systems employed in the IoT domain. Traditional energy harvesting applications use large energy storage devices to supply the power to the system whenever needed. Batteryless energy harvesting techniques have advantages to operate long periods of time without maintenance. In this study, we designed and implemented a supercapacitor-based, solar-powered wireless embedded system that can operate autonomously without the need of maintenance and battery replacement. Our goal is to explore and analyze the applicability and usefulness of batteryless wireless data communication and self-powered smart devices using energy harvesting technique in the IoT environment. In our experiments, we observed that our prototype boards operate well with low-power consumption without any performance degradation. Cite this article as : Yuksel ME. Design and Implementation of A Batteryless Wireless Embedded System for IoT Applications. Electrica, 2019; 19(1): 1-11.

A Batteryless Energy Harvesting Storage System for Implantable Medical Devices Demonstrated In Situ

We report a wireless energy harvesting and telemetry storage system in 180 nm CMOS technology, demonstrated in situ in rat carcass. The implantable device has dimensions 13 mm × 15 mm and stores 87.5 mJ, providing a self-powering time of 8.5 s transmitting through tissue. We utilize an all-solid-state flexible supercapacitor of breakdown voltage 0.8 V and capacitance 400 mF to harvest incoming wireless power, followed by a boost converter CMOS that drives an active wireless transmitter at 1.5 V at 2.4 GHz in the industrial, scientific, and medical (ISM) band. The DC/DC converter component and switching frequency selection were guided by genetic algorithm analysis and use digital feedback to control the pulse width modulation (PWM), which slowly modifies the duty cycle to control output voltage fluctuations. This implantable medical device system presents the roadmap for batteryless energy harvesting in vivo and in clinical environments, exhibiting the highest operating storage density of 450 μJ/mm2 reported to date.

Dual-Source Self-Start High-Efficiency Microscale Smart Energy Harvesting System for IoT

This paper presents a low-power batteryless energy harvesting system for Internet of Things (IoT) applications. A dual-mode dc–dc converter is used to harvest the energy of a microscale photovoltaic (PV) transducer and provides energy, in the boost mode, to a super capacitor for storage. In the buck mode, the dc–dc converter provides energy to the load on demand. A piezoelectric transducer is used as a secondary input source to guarantee system self startup. The proposed system includes a smart control to adaptively adjust the number of sensors at the load, leading to better usage of the available energy at any given time. The implementation also includes a programmable switch sizing to optimize the overall system's efficiency for different load conditions. A maximum power point tracking is used to extract the maximum power of the PV transducer under various illumination conditions. The system has been implemented in a CMOS 130-nm technology and tested in various modes of operation. Self startup has been verified, and a peak efficiency of 90.5% has been measured.

Vibration Based Energy Harvesting Interface Circuit using Diode-Capacitor Topologies for Low Power Applications

<span>A battery-less energy harvesting interface circuit to extract electrical energy from vibration has been proposed in this paper for low power applications. The voltage doubler integrated with DC – DC boost converter circuits were designed and simulated using MultiSIM software. The circuit was then fabricated onto a printed circuit board (PCB), using standard fabrication process. The Cockcroft Walton doubler was chosen to be implemented in this study by utilizing diode-capacitor topologies with additional RC low pass filter. The DC – DC boost converter has been designed using a CMOS step -up DC – DC switching regulators, which are suitable for low input voltage system. The achievement of this interface circuit was able to boost up the maximum voltage of 5 V for input voltage of 800 mV.</span>

Capacity of channel with energy harvesting transmitter

The authors propose a new technique to model the arriving energy's knowledge (AEK) in the energy harvesting (EH) communication systems. They consider a batteryless EH transmitter with the AEK non-causally provided to it. They show that the capacity of the authors' model in general case, that is, discrete memoryless channel, can be derived through a binning scheme. This resembles a Gelfand–Pinsker type capacity formula which intuitively is the result of treating the energy as a channel state. Moreover, they investigate two especial cases of binary and Gaussian channels with the EH transmitters. In the binary symmetric channel with EH transmitter (BSCEH), their coding scheme leads to achieve the capacity of the classic binary symmetric channel (BSC). In the batteryless Gaussian channel with EH transmitter, the upper bound on the capacity is derived, and it is shown this bound is less than the capacity of the EH Gaussian channel with infinite battery.

Tunnel FET RF Rectifier Design for Energy Harvesting Applications

Radio-frequency (RF)-powered energy harvesting systems have offered new perspectives in various scientific and clinical applications such as health monitoring, bio-signal acquisition, and battery-less data-transceivers. In such applications, an RF rectifier with high sensitivity, high power conversion efficiency (PCE) is critical to enable the utilization of the ambient RF signal power. In this paper, we explore the high PCE advantage of the steep-slope III-V heterojunction tunnel field-effect transistor (HTFET) RF rectifiers over the Si FinFET baseline design for RF-powered battery-less systems. We investigate the device characteristics of HTFETs to improve the sensitivity and PCE of the RF rectifiers. Different topologies including the two-transistor (2-T) and four-transistor (4-T) complementary-HTFET designs, and the n-type HTFET-only designs are evaluated with design parameter optimizations to achieve high PCE and high sensitivity. The performance evaluation of the optimized 4-T cross-coupled HTFET rectifier has shown an over 50% PCE with an RF input power ranging from -40 dBm to -25 dBm, which significantly extends the RF input power range compared to the baseline Si FinFET design. A maximum PCE of 84% and 85% has been achieved in the proposed 4-T N-HTFET-only rectifier at -33.7 dBm input power and the 4-T cross-coupled HTFET rectifier at -34.5 dBm input power, respectively. The capability of obtaining a high PCE at a low RF input power range reveals the superiority of the HTFET RF rectifiers for battery-less energy harvesting applications.

A Batteryless 19 $\mu$W MICS/ISM-Band Energy Harvesting Body Sensor Node SoC for ExG Applications

This paper presents an ultra-low power batteryless energy harvesting body sensor node (BSN) SoC fabricated in a commercial 130 nm CMOS technology capable of acquiring, processing, and transmitting electrocardiogram (ECG), electromyogram (EMG), and electroencephalogram (EEG) data. This SoC utilizes recent advances in energy harvesting, dynamic power management, low voltage boost circuits, bio-signal front-ends, subthreshold processing, and RF transmitter circuit topologies. The SoC is designed so the integration and interaction of circuit blocks accomplish an integrated, flexible, and reconfigurable wireless BSN SoC capable of autonomous power management and operation from harvested power, thus prolonging the node lifetime indefinitely. The chip performs ECG heart rate extraction and atrial fibrillation detection while only consuming 19 μW, running solely on harvested energy. This chip is the first wireless BSN powered solely from a thermoelectric harvester and/or RF power and has lower power, lower minimum supply voltage (30 mV), and more complete system integration than previously reported wireless BSN SoCs.