This study proposes a novel asymmetric rotor structure with tuning‐fork flux barriers for a permanent magnet (PM)‐assisted synchronous reluctance machine (PMA‐SynRM) to improve the torque characteristics. The proposed asymmetrical rotor structure can effectively decrease the flux leakage inside the rotor, as well as ensure the maximum values of the magnetic torque and the reluctance torque are near the same current phase angle as each other to achieve better utility. To realise this, the frozen permeability method is implemented to separate the total torque into the reluctance torque and the magnetic torque via a two‐dimensional finite‐element method – JMAG‐Designer. To achieve the optimal torque characteristics in the proposed model, the Kriging method and a genetic algorithm are used for getting the optimised model. The contribution of this investigation into motor performance is validated by comparing the proposed model with a conventional PMA‐SynRM with a symmetric rotor structure. Beyond that, all machine models are the same size, have the same number of magnets and are operated under the same conditions. A prototype of the proposed model is experimentally verified, i.e. the simulation results agree with the experimental results.

A built-in wave energy converter (BI-WEC) is a type of WEC that is fully encapsulated within a floating body that is easy to integrate and promotes reliability. Significant advantages in integration and reliability make BI-WECs a promising pathway to achieve an in situ power supply for massive distributed marine equipment (such as ships, buoys, or USVs). A comprehensive review of the recent advances in built-in wave energy converters can help address the most relevant issues in BI-WEC development. This study enumerates recent progress on BI-WECs (energy capture, power take-off, and control) and summarizes the characteristics of various designs. Different design philosophies and technical pathways can be better understood through the classification and analysis offered by this study. This review helps to form a basic understanding of BI-WEC development to achieve in situ power sustainability for a large amount of distributed marine equipment in long-term sustained marine operations.

In this paper, a novel structure is proposed for a wound rotor synchronous machine with a small ferrite magnet in each rotor pole. The key is to achieve a higher reluctance torque term and also acquire torque-angle approaching that would allow the field torque and reluctance torque to reach maximum values at the closed current phase angle for efficient production of the average total torque. The assisting ferrite magnet in the proposed model helps compensate the q-axis flux while keeping the d-axis flux unchanged as much as possible, for enhancing reluctance torque and power factor. Meanwhile, the assisting ferrite magnet makes an asymmetrical magnetic flux distribution to close the current phase angles between the maximum of the field torque and the reluctance torque. Moreover, the related parameters of the assisting ferrite magnet in the proposed structure were determined by optimal techniques using the Kriging method and genetic algorithm. In addition, the potential for demagnetization of the assisting magnet was analyzed and the results verified that this would not affect the motor output performance. Finally, prototypes were manufactured for the experiments to verify the principle analysis and finite element analysis results.

In this paper, a rotary-linear motor that achieves rotary and linear motions with a simple one-air-gap structure, low rotary ripple, and smooth linear force is proposed. The proposed motor combines a five-phase unipolar surface-mounted permanent-magnet (USPM) and a voice coil structure to simplify the motor structure, which motor can be named as rotary-linear surface-mounted permanent-magnet voice coil motor (RL-SVCM). And because of the characteristics of the rotary five-phase armature circuit and linear voice coil circuit, the proposed motor can provide low rotary ripple and smooth linear force. For designing the motor, the magnetic equivalent circuit (MEC) method is used to study the relationship between the linear force performance and motor structure parameters, and the effect of the flux bridges on the linear force and rotary torque. Due to uncertain variables in MEC, the FEM method is used to analyze the precise output result of rotary torque and linear force, and non-interaction between rotary and linear motions.

This paper proposes a rotary-linear surface-mounted permanent magnet (PM) voice coil motor (RL-SVCM) with PM flux bridges in place of the iron flux bridges in a traditional RL-SVCM for enhancing average torque and force ripple but slight damage of torque ripple and average linear force. The iron flux bridges in a basic RL-SVCM cannot participate in the generation of rotary torque. In contrast, the PM flux bridges in the proposed RL-SVCM can participate in the generation of rotary torque. The magnetic equivalent circuit (MEC) is used to analyze the magnetic circuits of the basic and proposed models. The results explain the reasons for the performance improvements achieved by the proposed motor. The finite element method (FEM) is used to derive the precise output performance of the basic and proposed motors. Additionally, a prototype of the proposed RL-SVCM with PM flux bridges was manufactured for experimental verification. Close agreement between the experimental results and FEM results validates the feasibility of the proposed RL-SVCM.

Vibration is ubiquitous in industrial environments, such as transportation systems and marine structures, offering a promising energy source for developing self-powered sensing systems. However, most existing vibration energy harvesters rely on a single transduction mechanism, which limits output performance, energy utilization efficiency, and system-level applicability. To address these limitations, we propose a vertically integrated electromagnetic-triboelectric hybrid vibration energy harvester (VI-HVEH), in which an electromagnetic generator (EMG) and a triboelectric nanogenerator (TENG) are compactly stacked and synergistically coupled. This work distinguishes itself by integrating two distinct energy transduction mechanisms within a compact architecture, enabling complementary energy conversion and improved energy utilization efficiency. Experimental results show that both the EMG and TENG units achieve optimal performance at an excitation frequency of about 20 Hz. At an acceleration level of 5 G, the EMG unit delivers a maximum output power of 521.43 mW with a low-voltage, high-current output, while the TENG unit produces a peak power of 128.41 mW with high-voltage, low-current characteristics. To efficiently regulate the pulsed high-voltage output of the TENG, a dedicated power management circuit comprising a gas discharge tube is employed, significantly enhancing the utilization efficiency of high-voltage pulses. By leveraging these complementary characteristics, the hybrid system exhibits accelerated capacitor charging and improved overall energy harvesting efficiency. Finally, a fully self-powered wireless sensing system is developed and demonstrated, achieving stable sensing and wireless data transmission without any external power supply. The integration of compact hybrid integration, effective energy management, and system-level validation highlights the novelty and practical applicability of the proposed VI-HVEH, providing a scalable solution for autonomous wireless monitoring in vibration-rich environments.