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The development of power generators that can function in harsh snowy environments and in contact with snow can be beneficial but challenging to accomplish. Herein, we introduce the first snow-based triboelectric nanogenerator (snow-TENG) that can be used as an energy harvester and a multifunctional sensor based on the principle of snow-triboelectrification. In this work, we used a 3D printing technique for the precise design and deposition of the electrode and triboelectric layer, leading to flexible, stretchable and metal-free triboelectric generators. Based on the single electrode mode, the device can generate an instantaneous output power density as high as 0.2 mW/m2, an open circuit voltage up to 8 V, and a current density of 40 μA/m2. In addition, the snow-TENG can function as a miniaturized weather station to monitor the weather in real time to provide accurate information about the snowfall rate, snow accumulation depth, wind direction, and speed in snowy and/or icy environments. In addition, the snow-TENG can be used as a wearable power source and biomechanical sensor to detect human body motions, which may prove useful for snow-related sports. Unlike conventional sensor platforms, our design works without the need for batteries or image processing systems. We envision these devices could potentially be integrated into solar panels to ensure continuous power supply during snowy weather conditions.

The development of highly sensitive sensors and power generators that could function efficiently in extreme temperatures and contact with fire can be lifesaving but challenging to accomplish. Herein, we report, for the first time, a fire-retardant and self-extinguishing triboelectric nanogenerator (FRTENG), which can be utilized as a motion sensor and/or power generator in occupations such as oil drilling, firefighting or working in extreme temperature environments with flammable and combustible materials. The device takes advantage of the excellent thermal properties of carbon derived from resorcinol-formaldehyde aerogel whose electrical, mechanical and triboelectric properties have been improved via the introduction of Polyacrylonitrile nanofibers and graphene oxide nanosheets. This FRTENG is not flammable even after 90 s of trying, whereas conventional triboelectric materials were entirely consumed by fire under the same conditions. The developed device shows exceptional charge transfer characteristics, leading to a potential difference up to 80 V and a current density up to 25 µA/m2. When integrated into firefighter's shoes, the FRTENG is able to discern the movements of a firefighter in hazardous situations, while providing the high thermal stability missing in conventional TENGs. The fire-retardant and self-extinguishing characteristics offered by the FRTENG makes it a path-breaking device for lifesaving wearable applications.

This paper presents a new speed control method for the induction motor (IM) following the finite control set-model predictive control (FCS-MPC) strategy. It adopts the cascaded control scheme, which consists of an inner model predictive torque control (MPTC) loop and outer model predictive speed control (MPSC) loop using two individual cost functions. This control approach implements a maximum torque per ampere (MTPA) operation in a wide speed range, which includes flux-increased and flux-limited modes. The MPSC produces the required torque to drive the IM at the reference speed. This torque is taken as the input of the inner MPTC, which in turn generates the optimal finite set of control input voltage. The control signals of the two MPC are constrained with the maximum limits of the system. The state feedback is achieved with a standard Kalman Filter, which estimates the non-measured load torque. The proposed control system is implemented and validated in experimental environment. The behaviour of the control system is evaluated by applying reference and disturbance steps to the system in different operational modes.

Wind energy plays an important role in new-energy market, and it has the potential to be one of the promising green electric energy sources. Thus, it is very important for scientists and researchers to develop alternative method for harvesting wind energy. Here, we introduce a farm structure consists of triboelectric nanogenerators (TENGs) for large-scale energy harvesting from natural wind. Depending on contact electrification based freestanding mode between two disks with patterns of micro-sized circular sectors, the TENG farm that works with the wind flow converts the low and high wind energy into electricity. Finally, the performance of the TENG and Darrieus turbines is compared both experimentally and theoretically, predicting the unique advantage offered by TENG at low rotation speed. Given the convincing characteristics, such as having little weight, low cost, environmentally friendly, and effortlessly connected, the TENG farm can be an effective way towards large-scale green energy harvesting from the wind.

Flexible and stretchable human-machine Interfacing devices have attracted great attention due to the need for portable, ergonomic, and geometrically compatible devices in the new era of computer technology. Triboelectric nanogenerators (TENG) have shown promising potential for self-powered human–machine interacting devices. In this paper, a flexible, stretchable and self-powered keyboard is developed based on vertical contact-separation mode TENG. The keyboard is fabricated using urethane, silicone rubbers and Carbon Nanotubes (CNTs) electrodes. The structure shows a highly flexible, stretchable, and mechanically durable behavior, which can be conformal on different surfaces. The keyboard is capable of converting mechanical energy of finger tapping to electrical energy based on contact electrification, which can eliminate the need of external power source. The device can be utilized for wireless communication with computers owing to the self-powering mechanism. The keyboards also demonstrate consistent behavior in generating voltage signals regardless of touching objects’ materials and environmental effects like humidity. In addition, the proposed system can be used for keystroke dynamic-based authentication. Therefore, highly secured accessibility to the computers can be achieved owing to the keyboard’s high sensitivity and accurate selectivity of different users.

Integration of photovoltaic (PV) energy into the electrical power system is increasing with the development in the PV technology. Transformer magnetizing inrush current problem occurs due to switching the trans-former into the service. This paper proposes an inrush current reduction technique using the PV power. The proposed procedure applies an opposite flux on the transformer using the PV power, then connect the trans-former with the electrical power network at a suitable instant of the grid voltage waveform. The switching in-stant depends upon the flux produced in the transformer primary winding by the PV system. The proposed procedure is applied on a single phase system and simulated in MATLAB R2012a/SIMULINK. The simula-tion results illustrate the suitable instant of switching to reduce the magnetizing inrush current and the corre-sponding total harmonic distortion (THD).

In this paper, permanent magnet–dual mechanical ports (PM–DMP) machine is used as an electrical variable transmission (EVT), instead of the Toyota hybrid system (THS) transmission, in hybrid electric vehicle (HEV). In this paper, a new tactic to strategise the power management and torque distribution in the studied HEV system is developed. This strategy is based on the combination of rule–based and fuzzy logic control (RB–FLC). According to this strategy, different architectures with all modes of operation of the series/parallel HEV based on PM–EVT have been achieved. Using the vehicle specifications, engine, battery, and other control parameters of the Prius HEV, the appealing features of PM–EVT unit and the proposed RB–FLC power management strategy are explored in comparison to the SPHEV obtained from ADVISOR 2002. The obtained results give a specific conclusion that the Prius SPHEV can be successfully replaced by the HEV based on the PM–EVT with the proposed control strategy.

Smart skin-like electronics are urgently crucial for artificial muscles, while the development of self-powered two-dimensional-like multifunctional material systems remains significant challenges. Here, we demonstrate a new class of printed smart electronic skin (SES) with multi-sensing properties and energy conversion capability using simple and cost-effective printing techniques. The resulting all-organic self-powering SES functioning as a human-monitoring device where it can detect a variety of external stimuli and works as an ultra-flexible biomechanical energy harvester. Remarkably, our SES exhibits excellent antibacterial properties in addition to self-adaptive performance under various conditions, such as being bent, cut, sewed, hammered, punctured, and washed. The proposed SES devices here have the promise for broad applications in future functional-wearables for human-machine interface, soft robotics, and skin prosthetics.

In this paper, we demonstrate the use of triboelectric nanogenerator (TENG) as a mean of mechanical light triggering to control InGaN-based light-emitting diodes (LEDs). Light extraction from the LED is two successive steps process. First, the voltage produced by the TENG is used to control the gate-to-source current of a MOSFET transistor through adjusting the transistor channel width and length. The second step is forwarding the drain-source current resulting from MOSFET transistor to the LED as its injection current to induce spontaneous emission from the LED surface to the air. Three LED colors are considered: red, green and blue. Significant emitted power from these InGaN-based LEDs in the RGB wavelength band is observed for both P-MOSFET and N-MOSFET transistor configurations. The emitted optical spectrum is controlled by optimizing the combined TENG-MOSFET-RGB LED geometry; dimensions and the bias voltage between the drain and source terminals of the MOSFET transistor. With recent advances in TENGs as an energy harvesting technology, it is expected that this study offers an approach to enhance the light extraction of various LED devices. With the enhancements in the performance of optoelectronic devices, the field of tribo-phototronics has attracted more attention, and in this work, we introduce the first theoretical framework, to the best of our knowledge, based on finite element modeling. This study provides significant insights into the working principles of tribo-Phototronic devices as well as guidelines for future device design.