带有MPPT功能的高效率光伏电池升压转换器芯片

为了提高光伏电池的收集效率和环境适应性,提出了一种带有MPPT功能的高效率光伏电池升压转换器芯片。该电路系统包括新型四相高效电荷泵模块、扰动观察法MPPT控制电路模块、反馈控制模块、纳安级电流基准、检测电路模块等。该芯片采用0.35μm BCD工艺设计、仿真并流片。芯片尺寸为3.15 mm×2.43 mm。测试结果表明,当光伏电池输出电压大于0.5 V时,升压转换器芯片输出电压提升到3V_in,电压转换效率可达99.4%。MPPT算法使输出功率提升8.53%。当输出负载电流为297μA时,最宽输出PCE达到85.1%。该芯片实现了高效升压光伏电池输出电压的目标。     

一种多模式四开关降压-升压型DC-DC转换器

为了提高电池能量利用率,延长便携式电子设备的电池使用时间,提出一种级联4开关降压-升压型DC-DC转换器.该电路采用多模式工作方式,能根据输入和输出电压的具体关系和不同的负载条件采取相应的控制策略,以提高转换器的效率;在电池电压的整个波动范围内,提供稳定的电压输出.整个系统使用1.5μm BCD(Bipolar-CMOS-DMOS)工艺设计实现.     

适用于双源能量收集的最大功率同步追踪电路

针对多数传统能量收集系统的能量来源单一、现有多源能量收集系统的追踪效率较低、输入功率范围较窄等问题,提出一种双源最大功率同步追踪电路(DSS-MPPT)。该电路实时同步追踪两个环境能量源的最大输出功率,通过设计数字控制电路,MPPT电路中两个比较器可以共用单边延时电路,从而提高电路的能量转换效率。该数字控制电路可实时切换输入能量源,使得系统仅需一个电感,从而降低能量收集系统的体积以及电路的复杂度。基于0.18 μm CMOS工艺的仿真表明,系统能量转换效率最高可达95.37%,并且在20 μW~1 mW宽输入功率范围内追踪效率始终高于98.53%。     

应用IoT系统的2”x 1”封装、10WAC/DC转换器

为了符合物联网(IoT)系统的最新要求,RECOM开发了一款高性价比、2'x1'封装的10W AC/DC转换器。该转换器在宽负载范围内的效率都很高,是IoT应用中理想的节能选择。转换器提供稳定的输出,输入电压范围为85至305VAC,可全球通用。IoT系统配备了许多不同的传感器进行实时数据交换,在智能基础设施中实现高效通信。IoT系统中大多数的传感器节点在待机状态下运行。     

交流适配器/电池供电系统的电源管理方案

便携式产品通常由交流(AC)适配器或电池提供系统电源,图1所示电路能够自动切换AC适配器和电池输入,为系统提供稳定的5V和3.3V输出,通过限制不必要的能量损耗有效延长电池寿命。该电路仅在撤掉AC适配器时吸取电池能量,适配器与电池输入之间输出电流达600mA;线性稳压器提供3.3V输出、电流达200mA。 图中IC1内部包括一路开关型稳压器和一路线性稳压器,独立的ON/OFF控制能够在开关型稳压器关闭时保持线性稳压器输出有效,此时,线性稳压器输入电压由IC2提供。IC2为开关型DC—DC转换器,能够将不稳定的AC适配器输入     

用于远程传感器的能量收集器

当前,电力电路正在采用一种全新的理念,即能量收集(energyscavenging)。该技术能够利用太阳能电池、压电发电机、以及其它能量转换设备来收集能量,然后将其转换为电能,并存储在电容器中,以备使用。很多情况下,传感器电路不需要持续运行,因此,在传感器停止工作期间,能量即可以得到补充。在此例中,太阳能电池及一个1F电容器用以为移动探测器提供能量,该移动探测器使用RF链路将发生的情况随时发送到中央监视器。这一类型的传感器极为方便,无需线缆,也无需更换电池。一些电路需要使用传感器来监控电容器的电压,并通过发送信号的方式告知其它电…     

TI超低功耗转换器加速消费类电子与智能家居的能量采集设计

日前,德州仪器(TI)宣布推出业界低功耗DC/DC降压转换器,与其它器件相比可将终端应用可使用的采集能量提升达70%,回答了"在多低的电压下可以工作?"的问题。该超低功耗电路可实现各种应用的无电池供电,如无线传感器网络、监控系统、烟雾探测器、可佩戴医疗设备以及移动附件等。低功耗DC/DC转换器TI TPS62736DC/DC转换器提供10uA至50mA输出电流的高电源转换效率,支持仅350nA的工作流耗与20nA的待机流耗。该转换器可在高于15uA的输出电流下实现超过90%的效率。TPS62736稳压器不但可为电源(如薄膜或常规电池,或是超级电容器等)降压,而且还支持可编程输出电压。     

DC-DC转换器设计

１开关型稳压器开关型稳压器通常利用电感、变压器或电容器作为储能元件来将输入能量传递给输出负载。其反馈电路用于调节能量的传输 ,保证在限定的负载电流范围内保持恒定的输出电压。转换器的基本电路结构包括升压型、降压型和反相型等 ,图１所示是ＤＣ -ＤＣ变换器的几种典型结构 ,当利用变压器作储能元件时 ,可以实现输出与输入之间的隔离。在电池供电系统中选择开关型ＤＣ -ＤＣ转换器可以获得较高的效率和较低的热耗 ,从而可有效延长电池的使用寿命。同时通过在输出级添加适当的滤波电路 ,还能够将输出电压纹波降至较小的范围。２开关…     

用于远程传感器的能量收集器

当前，电力电路正在采用一种全新的理念，即能量收集（energy scavenging）。该技术能够利用太阳能电池、压电发电机、以及其它能量转换设备来收集能量，然后将其转换为电能，并存储在电容器中，以备使用。很多情况下，传感器电路不需要持续运行，因此，在传感器停止工作期间，能量即可以得到补充。在此例中，太阳能电池及一个1F电容器用以为移动探测器提供能量，该移动探测器使用RF链路将发生的情况随时发送到中央监视器。这一类型的传感器极为方便，无需线缆，也无需更换电池。     

具有能量收集管理的无线传感器节点设计

传感器网络作为物联网的底层核心和感知前端,在实际应用中要求能够长时间连续工作,但是基于电池的有限能源供给严重限制了其灵活设计和长期部署,成为许多领域中影响其应用的重大挑战.能量收集技术使得节点可以从环境获取能量给自身充电,为延长网络寿命提供了一个有效的技术手段.本文设计了一种基于CC2650的无线传感器网络节点,结合基于LTC3331的多源环境能量收集技术,形成了一套完整的带能量补充的微功耗传感器节点.实验通过太阳能板作为能量收集前端进行验证,结果表明其可以实现环境能量的收集和累积存储并驱动节点运行.该节点体积小,自治工作时间长,可以广泛用于环境和结构监测等领域.     

Efficient Maximum Power Tracking of Energy Harvesting Using a μController for Power Savings

This letter describes an efficient technique for maximum power point tracking (MPPT) of an energy harvesting device. It is based on controlling the device voltage at the point of maximum power. Using a microcontroller with a power saving technique, the MPPT algorithm maintains the maximum power with low power consumption. An experiment shows that the algorithm maximizes the energy transfer power using an energy management IC fabricated in a 0.18‐μm process. Compared to direct energy transfer to a battery, the proposed technique is more efficient for low‐energy harvesting under variable conditions.     

Analysis and Experiment of Self-Powered,Pulse-Based Energy Harvester Using 400 V FEP-Based Segmented Triboelectric Nanogenerators and 98.2% Tracking Efficient Power Management IC for Multi-Functional IoT Applications

A self-powered system for the Internet of Things (IoT) is demonstrated for efficient energy harvesting of naturally available mechanical energy. In this system, new contact-separation mode triboelectric nanogenerators (TENGs), based on fluorinated ethylene propylene, are investigated using the segmented multi-TENG configuration to reduce the effect of parasitic capacitance. The TENG extraction is optimized using a unit step excitation involved with the Dawson function to achieve a high voltage (400 V) and a high current (26.6 µA). To fully extract the power of the TENGs, the power management integrated circuit (PMIC) specially designed for adaptively controlled, high-voltage (HV) maximum power point tracking (MPPT) is proposed. The PMIC implemented in a bipolar CMOS-DMOS 180 nm process can handle a wide input range (5–70 V) by consuming 420 nW. The MPPT control allows a wide range of impedance matching from 10 to 300 MΩ, achieving a tracking efficiency of up to 98.2%. The end-to-end efficiency of 88% demonstrates state-of-the-art performance. To supply a higher instantaneous power than that available from the TENGs, a duty-cycling technique is successfully demonstrated. The proposed energy harvesting system provides a promising approach to realizing sustainable and autonomous energy sources for various IoT applications.     

Development of Wi-Fi Based Home Energy Monitoring System for Green Internet of Things

Green Internet of things (IoT) has been heralded as the next big thing waiting to be realized in energy-efficient ubiquitous computing. Green IoT revolves around increased machine-to-machine communications and encompasses energy-efficient wireless embedded sensors and actuators that assist in monitoring and controlling home appliances. Energy efficiency in home applications can be achieved by better monitoring of the specific energy consumption by the appliances. There are many wireless standards that can be adopted for the design of such embedded devices in IoT. These communication technologies cater to different requirements and are classified as the short-range and long-range ones. To select the best communication method, this paper surveys various IoT communication technologies and discusses the advantages and disadvantages to develop an energy monitoring system. An IoT device based on the Wi-Fi technology system is developed and tested for usage in the home energy monitoring environment. The performance of this system is then evaluated by the measurement of power consumption metrics. In the efficient deep-sleep mode, the system saves up to 0.3 W per cycle with an average power dissipation of less than 0.1 W/s.     

多方向压电振动能量收集技术研究与进展

煤矿井下综采设备工作时会产生较大振动,利用压电振动能量收集系统实现煤矿综采设备无线监测节点自供电,有望解决传统化学电池使用寿命有限,更换困难,污染环境等问题。传统线性能量收集装置的谐振频率难以满足外界振动复杂多变的要求,导致俘能效率低下。如何提高压电振动系统俘能效率是一个亟待解决的问题。多方向是提高复杂振动环境压电俘能效率的有效途径。该文从击打式和悬臂梁式两种能量转换方式总结分析国内外学者在多方向振动能量收集方面的研究,从阵列式、自调谐、非线性、频率泵浦、弹性放大器等方面分析多方向振动能量收集系统的效率提升技术;最后,从采用新型压电材料提升俘能效率、考虑非线性和多场耦合动力学优化俘能结构、工程应用研究等方面对多方向压电能量收集技术进行了展望。     

绿色物联网:需求、发展现状和关键技术

从物联网的概念提出至今,政产学研用各界大力投入物联网的研究和建设工作中.当前,物联网主要集中在传统的技术设计和行业应用方面,作为信息技术产业的重要组成部分,其建设和发展必然受到能源和成本问题的制约,绿色节能也是目前关注较少的一个领域.为从根本上理清物联网目前存在的能耗问题,为建设高能效的绿色物联网提供理论依据,本文首先介绍了绿色物联网的基本概念,对绿色物联网的发展进行了分析,然后根据物联网的发展需求,结合我国物联网的发展现状,对当前绿色物联网各层的能耗构成进行了具体分析,总结了产业界和学术界在绿色物联网方面的推动工作;同时以物联网的层次关系为出发点,对绿色物联网各层的绿色节能和能效优先设计技术进行了深入分析和梳理,然后结合物联网层次关系给出了当前研究界对绿色物联网研究的各个环节的主要技术,最后对绿色物联网的未来发展进行了总结和展望.     

IOT Based Augmented Perturb-and-Observe Soft Switching Boost Converters for Photovoltaic Power Systems in Smart Cities

This paper focuses on IOT based soft switching boost converter based solar energy applications for smart cities and making cities smarter and greener around the globe. It presents one of the applications of the Internet of Things to design and implementation of a highly efficient boost converter used for powering the Arduino and the Bluetooth device for controlling the switching of the led and buzzer by using smart city applications. The soft switching boost converter is essential to maximize the low-level voltage obtained from the solar board to the enhanced voltage conversion ratio for the efficient electric power generation. In this paper, the three separate methodologies of DC–DC boost converters with additional resonant/snubber circuit and resistive load associated with solar panel modules proposed with maximum power point tracking (MPPT) control. The MPPT is obtained by modified augmented perturb and observe algorithm. IoT helps Smart City(SC) systems to support various network functions throughout the generation, transmission, distribution and consumption of energy by incorporating IoT devices (such as sensors, actuators and smart meters), as well as by providing the connectivity, automation and tracking for such devices. It is utilized to extract the most extreme power from solar panel by controlling the duty ratio of the suggested soft switching based boost converter. In this paper a smart IOT system is used to control and monitoring the effect of reference power variations, parameter values to the voltage control to the converter. The solar panel, boost converter and the MPPT is modeled using MATLAB/SIMULINK environment and reach the power transfer efficiency up to 97%.     

A battery-less BLE smart sensor for room occupancy tracking supplied by 2.45-GHz wireless power transfer

Wireless power transfer (WPT) has emerged as a solution for supplying smart sensors for long-term battery-less deployment. Because the amount of power harvested by the smart sensor is limited due to WPT path loss, the optimization objective is twofold: achieving ultra-low-power operation for the sensing task and improving the harvesting efficiency even at low incident power. In this paper, we focus on the use case of a Bluetooth LE-connected motion detection system supplied by 2.45-GHz RF power. The full system (RF energy harvester, power management, sensor transducer and interface, control, data processing and wireless transmission) is implemented using low-power off-the-shelf components. In the sensing sub-system, ultra-low-power operation is achieved by the duty-cycling of the sensor interface and by an event-driven scheme for communication. In the harvesting sub-system, the design of the matching network and rectifier, combined with maximum power point tracking (MPPT), is optimized for increasing the power harvesting efficiency (PHE) at low incident power. Measurements show a total reduction in the power consumption for the sensing sub-system by a factor 20. When using custom WPT waveform with high peak-to-average power ratio, the RF energy harvester is functional with an incident RF power starting from −20 dBm. The smart sensor is able to perform its motion-detection task with an incident power as low as −17.3 dBm.     

Modeling and analysis of multiple access channel capacity based on hybrid energy storage and energy harvesting

Energy harvesting (EH) has been considered as a promising technology to solve the constrained energy problem in the devices of IoT with its advantages of flexible deployment and sustainable energy supply.For multiple access channel with energy harvesting,a hybrid energy storage structure model composed by super capacitor and battery was proposed for the devices of IoT.According to the peculiarities of medium access channel and energy harvesting system,an optimized energy allocation strategy with exponential-type decline (ETD) was presented,the upper and lower bounds of the average throughput were deduced,in particular,the gap of two bounds was derived to be a constant.The channel capacity was further obtained by utilizing the relationship between the average throughput and the channel capacity.In the simulations,the effect of harvested energy,storage capacity and the number of nodes on the channel capacity were analyzed respectively.Experiment results show that compared with the conventional wireless node with single battery storage,the proposed hybrid energy storage structure can improve the harvested energy value and increase the multiple access channel capacity by using adaptive modulation scheme when transmitting the signals.     

Age of information analysis for internet of things information status update system with cellular backhaul and dedicated energy harvesting beacons

The Internet of Things (IoT) that is usually deployed with the assistance of cellular backhaul and energy harvesting (EH) is characterized by the status update freshness. However, the traditional nature EH results in the loss of information freshness due to the randomness of nature energy process. Although using wireless energy transferring (WET) to charge sensors can overcome this problem, this method has low-energy efficiency. With these considerations, this paper proposes a novel IoT system under cellular communication scenario by simultaneously exploiting the nature EH and WET. The proposed IoT system is consisted of a cellular backhaul subsystem, a wireless EH and transferring (WEHT) subsystem, and a wireless sensor status update subsystem. The WEHT subsystem employs the dedicated power beacons harvesting energy from natural energy source and transferring the harvested energy to sensor. For the proposed IoT system, this paper first investigates the WEHT subsystem and constructs the Markov Chain (MC) of discrete energy states as well as the MC state transition matrix. Second, the average AoI and peak AoI (PAoI) are formulated by separately considering cellular backhaul and EHTBs. The AoI (PAoI) comparison shows that the proposed EHTB-based IoT system can outperform the conventional non-EHTB one where the sensor directly harvests energy from natural source. At the same time, the numerical results exploit the impact of system parameters on AoI and PAoI, respectively. It is found that there exists a trade-off between the nature energy arrival and EHTB energy transfer so that the average minimum AoI and PAoI are achieved.     

A TEG Efficiency Booster with Buck–Boost Conversion

A thermoelectric generator (TEG) efficiency booster with buck–boost conversion and power management is proposed as a TEG battery power conditioner suitable for a wide TEG output voltage range. An inverse-coupled inductor is employed in the buck–boost converter, which is used to achieve smooth current with low ripple on both the TEG and battery sides. Furthermore, benefiting from the magnetic flux counteraction of the two windings on the coupled inductor, the core size and power losses of the filter inductor are reduced, which can achieve both high efficiency and high power density. A power management strategy is proposed for this power conditioning system, which involves maximum power point tracking (MPPT), battery voltage control, and battery current control. A control method is employed to ensure smooth switching among different working modes. A modified MPPT control algorithm with improved dynamic and steady-state characteristics is presented and applied to the TEG battery power conditioning system to maximize energy harvesting. A 500-W prototype has been built, and experimental tests carried out on it. The power efficiency of the prototype at full load is higher than 96%, and peak efficiency of 99% is attained.