Synchronous Electric Charge Extraction Research Articles

A self-powered interface circuit for piezoelectric and photovoltaic energy extracting

This paper presents a high-efficiency multi-source energy harvesting system consisting of a piezoelectric rectifier, a photovoltaic maximum power point tracking circuit and a fast self-startup circuit for powering wireless sensor nodes. Synchronous electric charge extraction techniques (SECE) are utilized to extract the piezoelectric energy when the deflection of piezoelectric energy harvester beam reaches its peak. Compared with other circuits, the proposed SECE technique can achieve piezoelectric and photovoltaic extraction simultaneously with a concise flyback topology structure. A novel maximum power point tracking method is adopted to enhance the robustness of operation against changing operating condition and improve the photovoltaic extraction efficiency. To remove the need for a battery, a simple and efficient self-startup circuit is introduced. The energy harvesting circuit is fabricated in 180 nm CMOS process. Measurement results show a fast self-startup at a relatively low light intensity of 120 lux is realized. The energy harvesting circuit is capable of outputting 189 μW power at 3.3 V piezoelectric open circuit voltage and 0.6 V photovoltaic input voltage.

A Frequency Up-Conversion Piezoelectric Energy Harvester Shunted to a Synchronous Electric Charge Extraction Circuit.

A frequency up-conversion piezoelectric energy harvester (FUC-PEH) consists of a force amplifier, a piezoelectric stack, a low-frequency oscillator (LFO), and a stop limiter. The force amplifier generates the amplification of stress on the piezoelectric stack. The LFO, comprising a spring and a mass block, impacts the stop limiter during vibration to induce high-frequency oscillations within the piezoelectric stack. In this paper, we represent and simplify the FUC-PEH as a lumped-parameter model based on piezoelectric material constitutive equations and structural dynamic theories. Using the electromechanical analogy, we developed an equivalent circuit model (ECM) of the FUC-PEH. A parametric study was performed to investigate the impact of system parameters, such as spring stiffness and concentrated mass, on the FUC-PEH performance. The collision-induced amplitude truncation (AT) effect enlarges the operation bandwidth. ECM simulations show that low-frequency input excitation is converted into a high-frequency output response, enhancing the energy conversion efficiency. Furthermore, we aimed to improve the FUC-PEH's performance using a synchronous electric charge extraction (SECE) circuit. Using the ECM approach, we established a system-level model that considers the electromechanical coupling behavior. The simulation results provide insights into the performance of FUC harvesters with SECE circuits and offer valuable design guidance.

A Novel Rectifier-Less Synchronous Electric Charge Extraction and Inversion Interface Circuit for PE Energy Harvesters

A Novel Rectifier-Less Synchronous Electric Charge Extraction and Inversion Interface Circuit for PE Energy Harvesters

A Triboelectric Energy Harvesting IC With High-Voltage Synchronous Electric Charge Extraction Strategy and Superior Systematic Efficiency

A Triboelectric Energy Harvesting IC With High-Voltage Synchronous Electric Charge Extraction Strategy and Superior Systematic Efficiency

Self-Powered Synchronous Electric Charge Extraction Rectifier for Rotational Electret Energy Harvester With Dual-Stage Electrodes

Self-Powered Synchronous Electric Charge Extraction Rectifier for Rotational Electret Energy Harvester With Dual-Stage Electrodes

A Self-Bias-Flip With Charge Recycle Interface Circuit With No External Energy Reservoir for Piezoelectric Energy Harvesting Array

This paper presents a piezoelectric energy harvesting (PEH) interface circuit using a new self-bias-flip with charge recycle (SBFR) technique without employing any additional energy reservoir. Traditional designs, including synchronous-switch harvesting on inductor (SSHI), synchronous-switch harvesting on capacitor (SSHC), synchronous electric charge extraction (SECE), etc., require additional capacitors or inductors to reverse the voltage on the PEH at the zero-crossing point. This design innovatively uses the inherent capacitors of the piezoelectric harvesters as the flipping capacitors. In order to improve the extract efficiency of the interface, the zero-crossing state is split into charge recycle stage and voltage-flip stage. For a piezoelectric array with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$2^{n}$</tex-math></inline-formula> PEHs, a configuration with (n-1) phases in the charge recycle stage is adopted to reduce the loss caused by direct charge neutralization. The charge redistribution loss is reduced by employing (2n+1) phases in the voltage-flip stage. The proposed principle has been implemented with discrete components and is verified by 3 different prototypes. The measurement results show that a flipping efficiency of 67% is achieved by utilizing SBFR with 4 PEHs. And the proposed interface can provide up to 5.2x improvement when compared with the full-bridge rectifier (FBR).

A Self-Powered Interface Circuit for Simultaneous Piezoelectric and Electromagnetic Energy Extraction

A self-powered circuit for the combination of synchronized electric charge extraction (SECE) and synchronous magnetic flux extraction (SMFE) interfaces (SP-SECE-SMFE) is proposed, which can simultaneously extract energy from piezoelectric transducer (PZT) and electromagnetic transducer (EMT). It reveals that when the energy extraction time of PZT and EMT is consistent, the electromagnetic energy harvested by SP-SECE-SMFE is greatly improved due to the action of the pulse piezoelectric voltage, and demonstrates how to use a resistance to adjust the energy extraction time of PZT. Simulation results show that the output power of SP-SECE-SMFE for the hybrid harvesting of piezoelectric and electromagnetic energy is 1.4-2.4 times higher than that of the sum when they are harvested separately under different frequencies and loads. Experimental results show that the maximum output power achieved by SP-SECE-SMFE is 1.7 times higher than that of the sum when are they harvested by the self-powered circuits of SECE and SMFE respectively, and is 2.2 times higher than that of the half-bridge rectifier circuit. The simulation and experimental results show the superiority of the proposed SP-SECE-SMFE circuit.

A Switched-Mode Self-Sensing Solution for Piezoelectric Synchronous Electric Charge Extraction

A Switched-Mode Self-Sensing Solution for Piezoelectric Synchronous Electric Charge Extraction

Multi-input SECE circuit with isolated active rectifier for piezoelectric energy harvesting

For multi-input piezoelectric energy harvesting, the issue of energy backflow between multiple Piezoelectric Transducer (PTZ) cause energy loss. Hence, an Isolated Active Rectifier (IAR) is proposed in this paper to address the problem. Based on the characteristic of energy isolation, the Multi-Input Synchronous Electric Charge Extraction Circuit (MI-SECE) with IAR can harvest energy from multiple PZTs with the arbitrary phase difference. The peak overall power conversion efficiency can reach up to 85.5%.

Energy Harvesting and Acceleration Measuring Based on Time-Division Multiplexing Operation of a Single Piezoelectric Transducer

This letter presents a novel approach called energy harvesting and acceleration measuring (EHAM) using a single piezoelectric (PZT) transducer. The EH subsystem is a synchronous electric charge extraction (SECE) interface combining with an energy management circuit, which can harvest energy from PZT. The AM subsystem is for measuring acceleration-related signals. A time-division multiplexing strategy is employed in the EHAM system, where vibration energy is harvested during one period and vibration acceleration is measured in another period, and the harvested energy also powers the AM circuit. The prototyped EHAM system is implemented based on discrete components and tested with a conventional cantilever-based PZT harvester. Experimental results show that the EHAM system can perform EH and AM operations in a time-division multiplexing way. The EH circuit can harvest 1.76 mJ energy during 22 s with a PZT open-circuit voltage of 6 V. The AM circuit can measure accelerations with an accuracy of 95% under the mechanical resonance condition. The EHAM solution can be a candidate for self-powered acceleration measurement.

Configurable Hybrid Energy Synchronous Extraction Interface With Serial Stack Resonance for Multi-Source Energy Harvesting

Conventional multi-source energy harvesters use the time-division multiplexing (TDM) scheme, where the inductor operates in discontinuous current mode (DCM) and fails to perform well in continuous current mode (CCM). This article presents a single-inductor hybrid energy synchronous extraction circuit with serial stack resonance (SSR) for multi-source energy harvesting. The proposed circuit incorporates a synchronous electric charge extraction (SECE) circuit for ac energy and two buck–boost circuits for dc energy with a single inductor, which can operate either in a TDM mode to harvest energy from different sources separately or in an SSR mode to extract energy from multiple sources synchronously. The proposed harvester is fabricated in a 0.18- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> CMOS process. It is configured with a photovoltaic (PV) cell, a thermoelectric generator (TEG), and two piezoelectric transducers (PZTs), where the number of PZTs is flexible to meet different application needs.

Mechanical Rectifier for Broadband Piezoelectric Vibration Energy Harvesting and Self-Adapting Synchronous Electric Charge Extraction

The synchronized switch interface circuit is believed to boost the piezoelectric power generation. The threshold voltage of electronic components causes rectification loss and delay of peak detection. This work reports a novel design of a mechanical rectification piezoelectric vibration energy harvester (MR-PVEH). Compact and low loss mechanical rectification is achieved by double switch with 5 electrodes contact at the cantilever tip. The switch as a mechanical stopper also contributes to broadband performance. The saturation voltage and response frequency range can be adjusted in modeling and simulation of nonlinear electromechanical coupling vibration. Self-adapting Mechanical rectification optimized synchronous electric charge extraction (M-OSECE) circuit is also proposed with less electronic components in this paper and shows an extra 60% increase in generated power than the traditional standard energy harvesting circuit (SEH) in test. This novel design gives a promising solution for self-adapting synchronous switching in broadband piezoelectric vibration energy harvesting.

Designing Peak Detector and Zero Crossing Detector for Asymmetric Synchronous Electric Charge Extraction

Piezoelectric energy harvesters are used to extract and generate electrical energy from ambient vibration sources. Under low excitation, the efficiency of the rectifier plays an important role in determining the efficiency of energy harvesters. Asymmetric Synchronous Electric Charge Extraction (ASECE) has higher efficiency compared to other conventional rectifiers. In this paper, the subcircuits of ASECE, i.e., peak detector and zero crossing detector, are designed. The proposed detectors can operate even at minimum frequency of 10[Formula: see text]Hz and in the temperature range of 0–125∘C. The proposed peak detector has shown detection in subthreshold region also. The performance of these detectors at different temperatures, supply voltages and frequencies has been reported in this paper. The detectors are designed using Tanner (2019.2) EDA tool at 180[Formula: see text]nm CMOS technology.

High performance piezoelectric vibration energy harvesting by electrical resonant frequency tuning

Extending the frequency bandwidth (BW) of vibration energy harvesters (VEH) that power wireless sensor nodes is of scientific and industrial interest. In this aim, electrical methods to tune the resonant frequency of piezoelectric harvesters with strong electromechanical coupling coefficients have been developed. In this work, we provide guidelines for designing such strongly coupled VEH and present a broadband harvester with high normalized power density (NPD). Through an analytical model, we explain how the coupling coefficient and the quality factor of a cantilever can be jointly maximized, thereby maximizing the figure of merit . The proposed cantilever prototype made of PZN-5.5PT and aluminum offers one of the best coupling coefficients among the state-of-the-art (k 2= 49.8%) and a high quality factor (Qm = 140). Associated to an appropriate tunable electrical interface (short-circuit synchronous electric charge extraction (SECE) in our case), the prototype exhibits a NPD of 12.0 mW g−2 cm−3 and a frequency BW of 36.0% (56.5 Hz around 157 Hz) at 0.34 m s−2 with a tunable electrical interface: the short-circuit SECE. This represents the highest product NPW × BW from state of the art.

A Multistep Charge Extractions and Voltage Bias-Flip (MCEBF) Interface Circuit for Piezoelectric Energy Harvesting Enhancement

In piezoelectric energy harvesting (PEH), interface circuits using synchronous switch actions, including synchronized charge extraction (CE) and/or bias-flip (BF), can achieve much higher energy harvesting (EH) capability, compared with the standard energy harvesting (SEH) bridge rectifier. In this article, a multistep charge extraction and voltage bias-flip (MCEBF) interface circuit is proposed to further enhance the harvesting capability under weakly coupling conditions. The EH enhancement is realized by reducing the dissipation in CE with multiple CE actions and simultaneously enlarging the extracted energy with a BF action. MCEBF can also generate positive and negative voltage rails via buck-boost topology to supply power for double-rail devices. The optimal control method of MCEBF is theoretically derived. In our experiment, under constant deflection excitation, the best MCEBF case offers 487%, 95%, and 49% more harvested power, compared with SEH, synchronous electric charge extraction (SECE), and parallel synchronized switch harvesting on inductor (P-SSHI) interface circuits, respectively. MCEBF also keeps the benefit of load independence as SECE does under weakly coupling conditions.

Self-Powered Single-Inductor Rectifier-Less SSHI Array Interface With the MPPT Technique for Piezoelectric Energy Harvesting

Piezoelectric energy harvester (PEH) arrays are practical solutions to the low and unreliable power output of a single PEH. However, most PEH circuits are developed for addressing the one-channel ac input from a single PEH. In this article, an extensible rectifier-less synchronized switch harvesting on inductor (ReL-SSHI) array interface with the maximal power point tracking (MPPT) function to manage the multiple ac inputs from the PEH arrays is designed. The ac–dc conversion is performed by the ReL-SSHI topology with passive peak switches featured with self-powered characteristic and fast cold-start. Only one shared inductor is employed, greatly reducing the circuit volume and cost. The MPPT module for each channel is implemented by a simple envelope detector and an ultra-low power hysteresis controller and achieves continuous energy extraction by adapting the fractional normal-operation voltage method. A developed discrete array interface able to handle three PEHs effectively executes the MPPT for each channel with the uphill and downhill response speeds of 2.0 and 7.1 V/s, and a maximal MPPT efficiency of 97.1%. This circuit boosts the power output by 485% compared with that by the traditional full-bridge rectifier, around 33% higher than that from existing synchronous electric charge extraction array interfaces.

Comparison of Four Electrical Interfacing Circuits in Frequency Up-Conversion Piezoelectric Energy Harvesting.

Efficiently scavenging piezoelectric vibration energy is attracting a lot of interest. One important type is the frequency up-conversion (FUC) energy harvester, in which a low-frequency beam (LFB) impacts a high-frequency beam (HFB). In this paper, four interface circuits, standard energy harvesting (SEH), self-powered synchronous electric charge extraction (SP-SECE), self-powered synchronized switch harvesting on inductor (SP-SSHI) and self-powered optimized SECE (SP-OSECE), are compared while rectifying the generated piezoelectric voltage. The efficiencies of the four circuits are firstly tested at constant displacement and further analyzed. Furthermore, the harvested power under FUC is tested for different electromechanical couplings and different load values. The results show that SP-OSECE performs best in the case of a weak coupling or low-load resistance, for which the maximum power can be 43% higher than that of SEH. As the coupling level increases, SP-SSHI becomes the most efficient circuit with a 31% higher maximum power compared to that of SEH. The reasons for the variations in each circuit with different coupling coefficients are also analyzed.

Discrete optimal couple tracking: A control scheme for electrical-tuning of strong coupling piezoelectric energy harvesters

In order to track the maximum power point of piezoelectric energy harvesters, an effective approach consists in designing interfaces able to electrically tune the harvester dynamics. Such interface should exhibit—at least—two tunable parameters in order to independently optimize the harvester damping and resonant frequency, that is, an electromechanical impedance matching of the real and imaginary parts of the electrical load. In order to optimize and control these two parameters, it is necessary to implement two control loops that simultaneously impact the harvester dynamics. Furthermore, these loops should combine quick convergence time with low-power consumption in order to react sufficiently fast to compensate for any shift in the vibration frequency and to consume only a small portion of the harvested power. In this paper, we propose a control-law based on the successive evaluation of couples of parameters in order to select the optimal one. First, we determine analytically the expression of a set of optimal couples valid for any two-parameters electrical interfaces. Thereafter, we prove that only a few well-chosen couples of parameters are sufficient to maximize the power on a large frequency band. The proposed methodology has been experimentally verified on a tunable interface, the short-circuit synchronous electric charge extraction. Combined with a strongly coupled piezoelectric energy harvester, we have been able to maintain the harvested power close to the maximal achievable power (i.e. &gt;70% of the maximal achievable power) on a 20 Hz frequency band, with only five couples of parameters. Such approach allows to substitute a multi-parameters convergence algorithm by a single-couple of parameters convergence algorithm, greatly simplifying the algorithm and reducing its convergence time.

Efficient self-powered piezoelectric energy harvesting interface circuit with wide rectified voltage

Synchronized Switching Harvesting on Inductor (SSHI) and Synchronous Electric Charge Extraction (SECE) are two classic interface circuit techniques for Piezoelectric energy harvesting. But the former has high peak output power with narrow rectified voltage range, while the latter has wide rectified voltage range with lower peak output power. This paper presents a self-powered interface circuit for piezoelectric energy harvesting to achieve a good balance between the two. The proposed interface circuit is based on the Series-SSHI (S–SSHI) and SECE. The circuit proposed can harvest energy through S–SSHI and SECE in positive and negative half cycles, respectively. Moreover, the figure of merit (FOM), optimal rectified voltage range (ORVR) and region of interest (SRoI) of simulation and experiment results are discussed. The maximum FOM of the proposed circuit is as high as 2.15, which is 1.68 times that of the SECE, and it can reach 6 times the ORVR of the S–SSHI. SRoI factor of the proposed circuit show that the proposed method has better performance. In addition, the circuit shows a simpler implementation compared with state-of-the-art designs.

Analytical Study of Piezoelectric Harvesters With SECE and SSHI Under Variable Excitation

A theoretical analysis aimed at predicting the power extracted from resonant piezoelectric vibration energy harvesters feeding synchronous switching-type electronic interfaces under variable mechanical excitation is proposed. In particular, for the widely used synchronous electric charge extraction (SECE) and synchronized switching harvesting on an inductor (SSHI) switching interfaces, the nonlinear equations describing the circuit behavior are solved under reasonable assumptions, and closed-form expressions of the extracted power are derived as a function of the circuit parameters and of the vibration characteristics, in the case of modulated mechanical vibrations. Numerical and experimental results validate the proposed closed-form expressions and show their usefulness for design purposes.