This paper presents a power converter topology with integrated driving and charging capability of switched reluctance motor (SRM) drive for electric vehicle (EV) application. In the driving mode, the bus voltage can be adjusted flexibly by the front-end buck converter, which meets the requirements of the speed open-loop and closed-loop control. Besides, higher voltage demagnetization can be achieved by connecting the upper freewheeling diodes of the asymmetric half-bridge converter to the battery bank, thus can accelerate the demagnetization process, extend the dwell angle and enhance the output of the motor. In battery charging mode, a bridgeless rectifier converter is constructed by utilizing two-phase windings of the SRM and the existing power devices of integrated power converter, without additional inductors and charging units. The battery charging and power factor correction (PFC) control can be realized by closed-loop control of charging current. Detailed analysis and experiments on a 1kW 12/8 structure prototype SRM validate the effectiveness of the proposed technologies.

Human body mechanical motion is considered as an ideal energy resource for portable or wearable devices. This paper presents an AA-sized electromagnetic energy harvester to convert the motion of human limbs motion into electrical energy. A cylindrical permanent magnet is freely moved in a 3D-printed tube wholly wrapped with coils. The outer dimensions of the device are 14 mm in diameter and 44 mm in height. Based on Faraday’s law a theoretical model was derived and the device size was optimized. The influence of the magnet and coil dimensions on the output power was analyzed by theoretical calculations and proved by experiment following. The optimized dimensions from two separate methods agrees well with each other. When the harvester prototypes are driven by hand shaking at 5 Hz, the average output power reaches to 63.9 mW with power density of 9.42 mW cm ⁻³ , which is 51% larger than that of the conventional tube electromagnetic energy harvester. While when the harvester is worn on ankle, a power of 4.2 mW can be obtained even at normal walking frequency of 1 Hz, corresponding to a power density of 0.62 mW cm ⁻³ , which is considerably higher compared with other devices of human energy harvesting. Furthermore, the new developed device is simple without needing any restoring spring and is easy to be fabricated.

Human sweat is intricately linked to human health, and unraveling its secrets necessitates a substantial volume of experimental data. However, conventional sensors fabricated via complex processes such as photolithography offer high detection precision at the expense of prohibitive costs. In this study, we presented a cost-effective and high-performance wearable flexible sweat sensor for real-time monitoring of K⁺ and Na⁺ concentrations in human sweat, fabricated using screen printing technology. Initially, we evaluated the electrical and electrochemical stability of the screen-printed substrate electrodes, which demonstrated good consistency with a variation within 10% of the relative standard deviation (RSD), meeting the requirements for reliable detection of K⁺ and Na⁺ in human sweat. Subsequently, we employed an “ion-electron” transduction layer and an ion-selective membrane to construct the sensors for detecting K⁺ and Na⁺. Comprehensive tests were conducted to assess the sensors’ sensitivity, linearity, repeatability, resistance to interference, and mechanical deformation capabilities. Furthermore, we evaluated their long-term stability during continuous monitoring and storage. The test results confirmed that the sensor’s performance indicators, as mentioned above, met the requirements for analyzing human sweat. In a 10-day continuous and regular monitoring experiment involving volunteers wearing the sensors, a wealth of data revealed a close relationship between K⁺ and Na⁺ concentrations in human sweat and hydration status. Notably, we observed that consistent and regular physical exercise effectively enhanced the body’s resistance to dehydration. These findings provided a solid foundation for conducting extensive experiments and further exploring the intricate relationship between human sweat and overall health. Our research paved a practical and feasible path for future studies in this domain.

In this paper, a synthetic sensorless starting scheme, which is based on pulse injection technology, is proposed for switched reluctance motor (SRM) drives to enhance the starting reliability. This scheme consists of a set of sensorless position estimation algorithms for different stages of SRM starting. In order to start the SRM from standstill stage smoothly, the initial driving phase is selected by pairwise comparing of the three-phase inductance. Then, to ensure reliable starting acceleration, a double inductance dynamic thresholds algorithm is developed for estimating the direct phase-driving signals. Meanwhile, to estimate the real-time rotor position, a position index pulse estimation algorithm, which is with phase lacking fault-tolerant capability, is developed based on an idle phase inductance threshold. By seamless switching between the above mentioned two algorithms, higher reliability of the sensorless starting control can be achieved. Furthermore, the performance of three pulse injection methods are compared, and the best one is then selected to reduce the influences of the high frequency pulse signals in the idle phases. The theoretical analysis and experimental results are provided to verify the feasibility of the proposed control scheme.

Reliable rotor position measurement is quite necessary for ensuring accurate commutation control in many kinds of motor drives, such as switched reluctance motor (SRM) and brushless dc motor (BLDC). Traditionally, the Hall sensors and photoelectric switch sensors are widely used in most of these low-cost motor drive systems. In these systems, the rotor position needs to be decoded from the discrete voltage pulses measured by the sensors. Thus, to develop an online position pulse signal fault diagnosis scheme with fast fault-monitoring capability is quite vital for avoiding the abnormal driving control and improving the overall system reliability. In this article, a position pulse signal fault diagnosis scheme based on synthetic hybrid-integral-threshold logic is proposed for SRM drives. In this method, the complementary position pulse signals of each sensor are used as the independent reference signals. By applying special integral calculations on each reference signals and capturing their rising and falling edges, the position pulse fault cases like high-level and low-level faults can be diagnosed immediately with the synthetic thresholds' comparison logic, respectively. To verify the validity of the proposed method, a 1-kW 12/8 structure SRM prototype with three independent Hall sensors installed is used as a test machine. The experimental results show that this method can diagnose the position fault of each position sensor independently and ensure very fast position fault detection even under dynamic operations with speed transients. Furthermore, the method can be implemented without additional hardware and complex computation, which is quite suitable for constructing a reliable position measurement module to assist the rotor position sensors.