Monitoring the displacement of tailings dam landslides is a pressing technical challenge in the mining industry. Traditional monitoring solutions relying on integrated air-ground-space surveillance and multi-sensor data fusion have prominent shortcomings, including high costs and excessive energy consumption. To tackle this problem, this paper presents a self-powered ultra-wideband (UWB) landslide displacement monitoring system for tailings dams, which integrates solar energy and radio frequency (RF) energy in a coordinated manner. The system is composed of fixed base stations and mobile tags: the fixed base stations are powered by solar panels and are capable of transmitting RF energy, sending and receiving ultra-wideband positioning signals, and calculating positioning data; the mobile tags are designed as passive devices that can receive RF energy and send and receive positioning signals to transmit surface displacement information of the dam body. Experimental results demonstrate that the system can effectively transmit surface displacement data of the dam body, verifying the feasibility of the technology. By innovatively adopting a passive tag design and a solar-powered supply scheme, the system completely eliminates reliance on external power sources. This research provides an economical and efficient new technical solution for tailings dam safety monitoring.

Piezoelectric energy harvesting interfaces are mainly categorized into single-stage conversion interfaces with high efficiency and cascaded conversion interfaces with high output power. However, the single-stage conversion interface has limited output power and lacks an MPPT configuration, while the cascaded conversion interface suffers from low end-to-end harvesting efficiency due to the cascaded conversion process. This paper proposes a load-independent Split-S-SSHI (SS-SSHI) interface with an envelope-tracking MPPT that can simultaneously achieve high output power and high end-to-end efficiency. In addition, the split S-SSHI eliminates the need for a rectifier capacitor and enhances the response speed of the MPPT. The proposed harvester is fabricated in a 0.18-$\mu $m CMOS process with a low quiescent current of 39 nA. Measurements indicate a maximum MPPT efficiency and end-to-end harvesting efficiency up to 99.5% and 91.9%, respectively, and the maximum output power reaches 9.7 times that of a conventional full-bridge rectifier.

Conventional duty-cycle-based (DCB) maximum power point tracking (MPPT) schemes generally assume a 50% duty cycle for operation at the maximum power point (MPP). However, due to nonideal losses in the piezoelectric transducer (PZT), such as dielectric loss, mechanical damping, and rectifieroff-state leakage, the actual optimal duty cycle deviates from this nominal value. This brief develops a theoretical model that incorporates these losses, which is derived, analyzed, and experimentally validated using a piezoelectric energy harvester (PEH) integrated with a bias-flip MPPT regulating rectifier (BMRR). Measurement results show that the optimal duty cycle ranges from 42.3% to 42.8%, under which the rectifier delivers 1.1 times the output power compared to operation at a fixed 50% duty cycle. Furthermore, the proposed rectifier achieves a peak power conversion efficiency (PCE) of 89.6% and demonstrates a 7.4-fold improvement in energy extraction compared to a full-bridge rectifier (FBR).

This work presents a self-feeding-priority power management strategy for a multi-input piezoelectric energy harvester based on the synchronous electric charge extraction (SECE). While conventional SECE can harvest intermittent vibration energy, it typically relies on battery power, which is continuously drained during vibration-free periods, causing net energy loss. The proposed solution prioritizes using harvested energy to sustain harvester operation, with surplus directed to storage, preventing consumption of stored energy when environmental kinetic energy is absent. In addition, by integrating a voltage clamping circuit and multistep charge extraction, the harvester efficiently harvests energy from diverse kinetic energy, operating over a wide input range. Fabricated in 180 nm CMOS technology, the harvester supports autonomous cold-start from 0.35 V and reliably harvests energy from periodic, shock, plucking, pressing, and walking-induced vibrations.

Currently, the automatic management of roadside parking space remains a significant challenge. Installing cameras next to each roadside parking space is an extremely expensive solution. Utilizing Bluetooth beacons to identify vehicles requires the installation of a Bluetooth device on each vehicle. This not only necessitates vehicle power supply but also poses installation difficulties. Additionally, the Bluetooth devices installed on parking space need to operate for extended periods, consuming a significant amount of electrical energy and requiring grid power supply. To reduce system costs, alleviate installation difficulties, and achieve complete autonomy in power supply, this article proposes a solar-powered and radio frequency (RF) energy transmission-based Internet of Things (IoT) management system for roadside parking space. We have designed both the mobile and fixed terminal of the system. The fixed terminal is powered by solar panels, enabling it to emit RF energy, retrieve vehicle information, automatically track time, and upload data. The mobile terminal is designed as a passive device capable of receiving RF energy and transmitting vehicle information. Through experimental testing, the system successfully achieves automatic retrieval and upload of vehicle information and parking duration, thereby validating the feasibility of the proposed system. Since the mobile terminal is a passive device and the fixed terminal is powered by solar panels, no external power supply is required. This project introduces for the first time the utilization of solar energy conversion into RF power supply, enabling the mobile terminal to function as a passive device without the need for external power or internal batteries.

This paper proposed a hybrid energy harvesting interface for wearable electronic devices, which achieves the simultaneous harvesting of piezoelectric and thermoelectric energy from the human body. The interface employs an inductor-shared converter with maximum power point tracking (MPPT) assistance to convert the piezoelectric energy rectified by a parallel synchronized switch harvesting on capacitor (P-SSHC) rectifier and the thermoelectric energy into a regulated output. The harvester employs an adaptive switching cycle (ASC) scheme to reduce the ripple of the tracking to improve the MPPT accuracy and end-to-end efficiency. In parallel, for efficient harvesting of both sources simultaneously, a multiplexed MPPT technique is incorporated into the harvester to reduce the chip area. In addition, to reduce the power loss resulting from the sampling phase of the FOCV method, a single-cycle fast-sampling technique is employed to assist the piezoelectric energy harvesting. The proposed hybrid energy harvester is fabricated by a$0.18 \mu \text{m}$CMOS process with a core area of$1.2 \times 0.7$mm2. The measured results show that the peak tracking efficiency of the PZT and TEG is 99.58% and 99.37%, respectively. The peak of end-to-end efficiency of the interface reaches 86.67%.

In this paper, a mutually synergistic hybrid energy harvesting (SHEH) circuit with both AC and DC energy harvesting capability is proposed. Within the proposed hybrid harvester, the vibration period of the piezoelectric transducer (PZT) is served as the switching signal for photovoltaic (PV) energy harvesting so that a dedicated clock generator is saved. Meanwhile, during the sampling phase, a small portion of the PV energy is injected into the PZT as an investment, which enhances the damping force and charge extraction of the PZT. Theoretically, the total synergistically extracted power from the proposed hybrid harvester is more than the sum of the power obtained from each transducer independently. The proposed SHEH circuit is fabricated with a 0.18-$\mu \text{m}$CMOS process. The buck-boost converter with zero-current switching control achieves a peak efficiency of 82.8%, and the maximum efficiency of piezoelectric energy harvesting can reach 4.5 times that of the full-bridge rectifier.