Low-power Energy Harvesting Research Articles

Mechatronized maximum power point tracking for electric field energy harvesting sensor

Electric field energy harvesting is a promising solution to energize a variety of self-sustainable wireless sensor nodes, which may be used in next-generation smart-grids. In this work, a low-power energy harvesting system targeting to extract energy from the electric field around energized wires is presented. Unlike the conventional electric field harvesters, the generator described in this work is intended on contactless household low voltage applications. A low-power design methodology to reduce power dissipation and to increase the harvested power has been implemented, considering the electric field scarcity in household applications and a variety of challenging design issues. In addition, the proposed harvester is equipped with a mechatronized maximum power point tracking system, that is used to automatically varies the location of the electrodes until harvesting the maximum power. The results show that the harvested power rises by approximately 94%, with a power density of 0.04 μW/cm2 in non-contact applications. Since the electric field is relatively low in residential environments, these results are highly promising to develop sensor nodes.

A 5.8 GHz Low-Power Energy Harvester for RF Wireless Power Transfer Systems

This paper presents the design and implementation of an RF energy harvester system at 5.8[Formula: see text]GHz for low-power wireless transmission applications. The potential application of the proposed system is to wirelessly power sensor nodes. First, a design methodology of the rectifier based on a theoretical approach is presented. The simulation results show an excellent correlation with the theoretical ones, proving the accuracy of the proposed design methodology. A prototype is fabricated and the simulation results are validated by the measurements. Then, the rectenna is combined to a commercial power management circuit and a load which emulates the behavior of a sensor. The power management circuit boosts and regulates the output DC voltage as well as stores the collected energy into a capacitor. Finally, the complete system is experimentally tested and excellent performances are demonstrated. The efficiency of the RF energy harvester is 24% at [Formula: see text]10[Formula: see text]dBm input power and 47% at [Formula: see text]5[Formula: see text]dBm input power which are the highest reported measured efficiencies at this frequency and at those power levels. The complete rectenna system is able to harvest 4.62[Formula: see text]mJ in 40 s and 192[Formula: see text]s for [Formula: see text]6[Formula: see text]dBm and [Formula: see text]10[Formula: see text]dBm input power, respectively allowing us to power wirelessly low-power electronic devices.

A Novel Dual-Input ZVS DC/DC Converter for Low-Power Energy Harvesting Applications

In this paper, a novel dual-input dc/dc topology is proposed for low-power energy harvesting applications. The converter is able to interface with two different power sources simultaneously. In the proposed topology, two boost converters are integrated with a shared diode and a filter capacitor, while the gate signals of two power MOSFETs are complimentary with certain dead-bands. The proposed topology may operate either in discontinuous-conduction mode or in hybrid conduction mode. In each operation mode, zero-voltage switching is achieved for both MOSFETs, while zero-current switching is achieved for the power diode, without any additional auxiliary circuit. Theoretical analysis, circuit modeling, and design considerations are also addressed in detail in this paper. Finally, a 10.1-W, 200-kHz prototype is designed and tested to validate the proof of concept. Experimental results are in accordance with the theoretical analysis.

A High-Efficiency Charger With Adaptive Input Ripple MPPT for Low-Power Thermoelectric Energy Harvesting Achieving 21% Efficiency Improvement

A high-efficiency charger for low-power thermoelectric energy harvesting with a method for improving the efficiency, which is called the adaptive input ripple (AIR) maximum power point tracking (MPPT) technique, is introduced in this paper. On the basis of the key finding that the end-to-end efficiency ( ηE-E ) is highly dependent on the amplitude of the input ripple of the charger (Δ V IN) in the low-power region, the proposed AIR MPPT technique adjusts Δ V IN to maximize ηE-E . Moreover, the minimum input power that allows the charger to maintain operation is enhanced by the proposed AIR MPPT technique. The proposed charger is implemented with 180-nm complementary metal oxide–semiconductor technology. An improvement of 21% in ηE-E is achieved with the proposed technique. Furthermore, the proposed technique enhances the minimum power by 7.5 μ W. The startup power and minimum power of the prototype are 37 and 6 μ W, respectively. The maximum ηE-E is 82%.

Analysis of MEMS electrostatic energy harvesters electrically configured as voltage multipliers

This paper presents the analysis of an efficient alternative interface circuit for MEMS electrostatic energy harvesters. It is entirely composed of diodes and capacitors. Based on modeling and simulation, an anti-phase gap-closing structure is investigated. We find that when configured as a voltage multiplier, it can operate at very low acceleration amplitudes. In addition, the allowed maximum voltage between electrodes is barely limited by the pull-in effect. The parasitic capacitance of the harvester and non-ideal characteristics of electronic components are taken into account. A lumped-model of the harvesting system has been implemented in a circuit simulator. Simulation results show that an output voltage of 22 V is obtained with 0.15 g input acceleration. The minimum necessary ratio between the maximum and minimum capacitances of the generators, which allows operation of the circuit, can be lower than 2. This overcomes a crucial obstacle in low-power energy harvesting devices. A comparison between the voltage multiplier against other current topologies is highlighted. An advantage of the former over the latter is to generate much higher saturation voltage, while the minimum required initial bias and the minimum capacitance ratio in both cases are at similar levels.

Fully Integrated Low-Power Energy Harvesting System With Simplified Ripple Correlation Control for System-on-a-Chip Applications

This paper presents a fully integrated energy harvesting (EH) system that even includes an input capacitor and a simplified ripple correlation control (RCC) maximum power point tracking (MPPT) method for low-power system-on-a-chip applications. The proposed system implements the RCC block with a charge pump (CP) that can be integrated into the chip, instead of the inductive switching converter that is commonly used for conventional RCC methods. The CP changes the input impedance by changing the size of the flying capacitor to ensure system reliability. The simplified RCC method is implemented using a low-power analog divider operated in a subthreshold region. A test chip fabricated in a 180 nm CMOS process achieves over 95% MPPT accuracy with a very small input capacitor of 5 nF and a low quiescent current of 2.6 μA. The chip size of the entire system is 8 mm2, and the harvested power range is from 6 μ W to 1.4 mW.

A Generic Power Management Circuit for Energy Harvesters With Shared Components Between the MPPT and Regulator

This paper presents a novel power management circuit (PMC) for harvesting the energy from the ambient. The proposed PMC comprises an energy harvester, a startup, a dc–dc boost converter, and a dc–dc buck converter. The PMC is capable of working with various low-power energy harvesters and can track the maximum power point after every 4.5 s. To achieve the maximum power point tracking (MPPT), an open-circuit-voltage-based method is used to transfer the maximum power from the energy harvester to the power optimized boost converter. The proposed MPPT scheme works for a wide range of equivalent source resistance of the energy harvester in the range of $20~\Omega $ –1 $\text{M}\Omega $ . An auxiliary energy harvester is used for the startup to avoid any external supply. Regulated voltage across a load is provided by the buck converter which features sharing the switches and inductor with the boost converter. The complete circuit is designed, optimized, and simulated in 180-nm mixed-mode CMOS technology using three different types of energy harvesters, which are precisely characterized and modeled. Post-layout simulated results are presented for the input power ranging from 150 nW to $500~\mu \text{W}$ for different values of source resistances ranging from $20~\Omega $ to 1 $\text{M}\Omega $ . For a source resistance of 100 $\text{k}\Omega $ , the efficiency of the boost converter is 39.91% and 89.91% at available power of 156 nW and 2.5 $\mu \text{W}$ , respectively. The buck converter is able to regulate the load voltage to 1 V across the load resistance ranging from $100~\Omega $ to 2 $\text{k}\Omega $ .

Network of thermoelectric nanogenerators for low power energy harvesting

We report the design, elaboration and measurements of an innovative planar thermoelectric (TE) devices made of a large array of small mechanically suspended nanogenerators (nanoTEG). The miniaturized TE generators based on SiN membranes are arranged in series and/or in parallel depending on the expected final resistance adapted to the one of the load. The microstructuration allows, at the same time, a high thermal insulation of the membrane from the silicon frame and high thermal coupling to its environment (surrounding air, radiations). We show a ratio of 45% between the measured effective temperature of the membrane, (and hence of the TE junctions), and the available temperature of the heat source. The temperature difference generated across the TE junction reaches a value as high as 60 K per mm. Energy harvesting with this planar TE module is demonstrated through the collected voltage on the TE junctions when a thermal gradient is applied, showing a harvested power of 0.06 μWatt for a 0.5cm2 chip for an effective temperature difference of 6.8 K. The optimization of nanoTEGs performances will increase the power harvested significantly and permit to send a signal by a regular communication protocol and feed basic functions like temperature measurement or airflow sensing.

A novel meander line integrated E-shaped rectenna for energy harvesting applications

In this article, design of a novel meander integrated E-shaped rectenna is presented. The designed rectenna operates at ISM frequency range from 2.2 to 2.5 GHz with acceptable reflection coefficients, gain and VSWR values. The designed rectenna is simulated using HFSS 15 (High Frequency Electromagnetic Field Simulation) and FR4 epoxy material is used in rectenna design for low cost having dielectric constant of 4.4 and thickness of 1.6 mm. In the rectifying stage full wave voltage doubler circuit is designed for DC power generation with SMS7630 Schottky diode and lumped circuit elements. The impedance matching circuit between the antenna and the rectifier is designed and simulated using advanced design system (ADS) software for efficient power transmission from the antenna to the load. The simulation and measurement results with different load and input power levels prove that the designed and implemented system can be used for low power energy harvesting applications in order to feed electronic components and battery free sensor networks.

Investigation of the Size Effect on the Nano-beam Type Piezoelectric Low Power Energy Harvesting

In this paper, size dependent beam type peizoelectric energy hardvester is investigated. For this goal, first nonlinear formulation of isotropic piezoelectric Euler-Bernoulli nano-beam is developed based on the size-dependent piezoelectricity theory then special beam type piezoelectric energy hardvester is probed for different parameters. Basic nonlinear equations of piezoelectric nano-beam are derived using principle of minimum of potential energy and variational method. To evaluate the formulation derived, static deformation and free vibration of the clamped-clamped piezoelectric nano-beam is investigated in the special case. The results of the formulation derived are investigated under different parameters, and particularly, the ability and performance of the beam type piezoelectric low power energy harvesting was evaluated in nanoscale.

Solar energy radiation measurement with a low–power solar energy harvester

Solar energy radiation measurements are essential in precision agriculture and forest monitoring and can be readily performed by attaching commercial pyranometers to autonomous sensor nodes. However this solution significantly increases power consumption up to tens of milliwatts and can cost hundreds of euros. Since many autonomous sensor nodes are supplied from photovoltaic (PV) panels which currents depend on solar irradiance, we propose to double PV panels as solar energy sensors. In this paper, the inherent operation of the low-power solar energy harvester of a sensor node is also used to measure the open circuit voltage and the current at the maximum power point (IMPP), which allows us to determine solar irradiance and compensate for its temperature drift. The power consumption and cost added to the original solar energy harvester are minimal. Experimental results show that the relation between the measured IMPP and solar irradiance is linear for radiation above 50 W/m2, and the relative uncertainty limit achieved for the slope is ±2.4% due the light spectra variation. The relative uncertainty limit of daily solar insolation is below ±3.6% and is hardly affected by the so called cosine error, i.e. the error caused by reflection and absorption of light in PV panel surface.

Low Frequency High Power Energy Harvester

The vibration energy harvester has become a hot spot because it can supply energy to device without battery. Four types of vibration energy harvesters with different operation modes are introduced in low frequency and high power aspects. They are electromagnetic, magnetostrictive, electrostatic and piezoelectric vibration energy harvester. Their developments are illustrated in detail. Meanwhile, the advantages and disadvantages of the four different structures are compared, and the performances are summarized. Among them, piezoelectric vibration energy harvester was studied the earliest. So, it has better performance and can be used widely.

Nonresonant Kinetic Energy Harvesting Using Macrofiber Composite Patch

Over the past decades, thanks to the progresses being made in low-power microelectronics, wireless technology, and energy harvesting techniques, we are observing an impressive increase in the use of wearable devices. Kinetic human energy harvesting is the most efficient and practical method to power them reducing the need of batteries replacement since walking or running is how humans already expend much of their daily energy. The present energy harvesting technologies still have several limitations. In this work, thanks to a mechanical framework specifically designed to reproduce the kinematic of a knee joint and actuated using recorded human motion patterns, we demonstrate the feasibility of the nonresonant employment of the macrofiber composites (MFCs) to scavenge energy from the various human body movements. Both the energy of periodic and aperiodic motions can be harvested. The electrical characteristics of the whole system focusing on the maximum power point of the MFC have been investigated to optimize the system power output.

Design of an Inductorless Power Converter with Maximizing Power Extraction for Energy Harvesting

An inductorless power converter for low-power energy harvesting is presented. The power converter for energy harvesting is employed to maximize power extraction from energy sources. The power converter is based on a capacitive boost converter which is divided into two stages; a number of first-stage in parallel and shared-stage. The first-stage maximizes power extraction from the energy source while the shared-stage operates as a conventional charge pump. For not only low-power energy source but also high-power energy source, the maximum power extraction is targeted by the proposed converter. The extracted power from energy sources enhances by range from 117% to 161% over the conventional design. The output current of the proposed converter with three first-stages is improved by 183% over conventional converter. The peak efficiencies achieved with three and one first-stage are 53.3% and 38.5% for the proposed and the conventional converters, respectively. The peak end-to-end efficiency is enhanced by 198% as compared to the conventional converter. The proposed inductorless power converter has been implemented on a 0.13μm CMOS process.

Solar energy harvesting wireless sensor network nodes: A survey

Solar energy harvesting that provides an alternative power source for an energy-constrained wireless sensor network (WSN) node is completely a new idea. Several developed countries like Finland, Mexico, China, and the USA are making research efforts to provide design solutions for challenges in renewable energy harvesting applications. The small size solar panels suitably connected to low-power energy harvester circuits and rechargeable batteries provide a loom to make the WSN nodes completely self-powered with an infinite network lifetime. Recent advancements in renewable energy harvesting technologies have led the researchers and companies to design and innovate novel energy harvesting circuits for traditional battery powered WSNs, such as Texas Instruments Ultra Low Energy Harvester and Power Management IC bq25505 [see https://store.ti.com/BQ25505 for Texas Instruments (TI) Ultra Low Power Boost Charger IC bq25505 with Battery Management and Autonomous Power Multiplexor for Primary Battery in Energy Harvester Applications datasheets (2015).]. In modern days, the increasing demand of smart autonomous sensor nodes in the Internet of Things applications (like temperature monitoring of an industrial plant over the internet, smart home automation, and smart cities) requires a detailed literature survey of state of the art in solar energy harvesting WSN (SEH-WSN) for researchers and design engineers. Therefore, we present an in-depth literature review of Solar cell efficiency, DC-DC power converters, Maximum Power Point Tracking algorithms, solar energy prediction algorithms, microcontrollers, energy storage (battery/supercapacitor), and various design costs for SEH-WSNs. As per our knowledge, this is the first comprehensive literature survey of SEH-WSNs.

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.

Effect of energy management circuitry on optimum energy harvesting source configuration for small form-factor autonomous sensing applications

Abstract The purpose of this paper is to investigate methods for improving power delivery from low-voltage, low-power energy harvesting sources, such as small form-factor dye-sensitised solar cells (DSSCs) as used in autonomous wireless sensing applications in buildings and homes. Energy harvesting powered wireless sensors enable existing and new structures to comply with Industry 4.0 and become smart buildings. Due to the size constraints of wireless sensor systems and the inherently low-power levels generated by energy harvesting sources, available power is limited and therefore the efficiency of power conversion and energy management circuitry connected between the source and output load has a significant impact on output power delivery. Most research to date focuses on improving the efficiency of individual components of such systems, without considering the impact of one stage on the others. In this paper, the potential of varying energy harvesting source configuration in combination with power converter operation to improve overall power delivery is investigated, where it is shown that by connecting sections of a DSSC in series rather than as a single cell, higher power conversion efficiency and therefore power delivery is achieved. Limitations to varying cell configurations and low-power DC-DC topologies are illustrated in order to demonstrate the scope of solutions available for small-sized, low-power, energy harvesting sources. It is shown that 8% improvement in overall power delivery is achieved for series vs. single cell connections within a fixed module area. This will translate into increased wireless sensor functionality and range, thereby furthering the development of the Industrial Internet of Things in buildings and homes.

Автономный маломощный источник энергии на основе широкополосного пьезоэлектрического преобразователя

Автономный маломощный источник энергии на основе широкополосного пьезоэлектрического преобразователя

Low-Power Energy Harvesting of Thermoelectric Battery Charger with Step-Up DC–DC Converter: Applicable Case Study for Personal Electronic Gadgets

AbstractA thermoelectric generator’s battery charging performance using an application of step-up direct current (DC)–DC converter to harvest energy was researched. In the first-stage study, temper...

Improved Energy Management System for Low-Voltage, Low-Power Energy Harvesting Sources

This paper focuses on improving the energy conversion process for low-voltage energy harvester powered wireless sensors by optimising the conversion stages for pulsed sensor operation. The proposed circuit has been designed to operate efficiently with both a low-voltage low-power energy harvester source and a low-power pulsed load. This ensures that continuous conversion losses are kept to a minimum and power is only delivered to the sensor when required. This has shown an increase in energy delivered to a sensor of up to 10% versus that of the best existing solution.