Purpose This paper aims to design a hybrid circuit topology to achieve constant current (CC) and constant voltage (CV) outputs for wireless battery charging. The designed system should have no wireless communications between the primary and secondary sides. Design/methodology/approach This study used theoretical analysis, modeling, simulation analysis and experimental verifications. Findings The proposed inductor-capacitor-capacitor-parallel/series (LCC-P/S) topology can achieve quasi-CC output with LCC-P compensation and CV output with LCC-S compensation. Compared with existing solutions, neither active control nor wireless communication is required, thus, which is simple and cost-effective. Originality/value This paper proposes a simple reconstructed LCC-P/S compensation topology of the inductive-power-transfer battery charger with CC and CV outputs to comply with the battery charging profile. The proposed method has no need of wireless communication between the primary and secondary sides.

Purpose The purpose of this paper is to meet load demand and reduce the impact of renewable energy sources’ intermittency, microgrids (MGs) rely on the coordinated operation of photovoltaic (PV), wind and hybrid renewable energy sources (HRSS). A hybrid energy storage system (HESS) integrates both long-term energy storage in batteries and short-term energy compensation in supercapacitors. To keep direct current (DC) MGs stable, manage power sharing and regulate DC bus voltage, which indicates a supply–demand imbalance, power electronic converters and good management procedures are necessary. To guarantee dependable operation of a low-voltage direct current (LVDC) MG in dynamic environments, robust power management is crucial. Design/methodology/approach Maintaining a constant DC bus voltage is essential for reliable LVDC MG operation and proper HESS charging/discharging under varying generation and load. To achieve this, a dynamic frequency-decoupled energy management strategy (DFD-EMS) is proposed, which uses a hierarchical structure to separate low-frequency (steady-state) and high-frequency (dynamic) power components, enabling coordinated power sharing among PV, wind, battery and supercapacitor units. The architecture uses cascaded PI-LagLead (PILL) controllers in outer voltage and inner current loops, as shown in Figure 3, enabling hierarchical coordination for stable and efficient power management. Findings This paper presented a robust control and energy management framework for LVDC MGs with hybrid renewable sources and hybrid energy storage. A dynamic frequency-decoupled EMS enabled coordinated power sharing between batteries and supercapacitors, with a novel cascaded PILL controller implemented in both voltage and current loops to enhance stability, transient response and noise rejection. The performance of the proposed PILL-based controller was systematically compared with four conventional cascaded control configurations using proportional–integral (PI) and lag-lead controllers. Comparative simulation and real-time hardware-in-the-loop (HIL) results across seven operating scenarios demonstrated superior DC-bus voltage regulation, reduced overshoot and faster settling times compared to conventional controllers. Quantitative analysis confirmed low overshoot (<4%) and fast settling times of less than 0.008 s under generation and load disturbances, validating the robustness and practical applicability of the proposed approach. The simplicity and real-time feasibility of the classical PILL-based framework make it well-suited for practical LVDC MG applications. Future work will focus on experimental validation using full-scale hardware prototypes and the extension of the proposed framework to grid-interactive DC MG architectures. Originality/value This work suggests a comprehensive control and power management framework for LVDC MGs integrating HRES and HESS. The significant contributions of this work are as follows: A novel cascaded control structure using phase-compensated PILL controllers in both the outer DC-bus voltage loop and the inner current loop is proposed. A dynamic frequency-decoupled EMS is proposed to enable coordinated power sharing among PV, wind, battery and supercapacitor sources. Comparative evaluation of five cascaded control configurations for HRES using HESS, including the proposed controller and four conventional control strategies designed and analysed for performance assessment: Outer PI–Inner PI, Outer LagLead–Inner LagLead, Outer PI–Inner LagLead, Outer LagLead–Inner PI and Outer PILL–Inner PILL (Proposed). A unified classical control framework with stability analysis is developed with the proposed cascaded PILL controller, which outperforms other classical configurations under diverse operating conditions. Although non-linear control strategies can provide enhanced dynamic performance, their practical implementation may require increased computational resources, accurate system modelling and higher tuning effort. For moderate-power 48 V LVDC MG applications rated at 1.2 kW, the proposed PILL-based controller offers an attractive trade-off between control performance, implementation simplicity and cost-effectiveness. The effectiveness and robustness of the proposed PILL-based DFD-EMS are validated through real-time HIL experiments under seven distinct operating scenarios involving independent and simultaneous variations in PV power, wind power and load demand. These results confirm reliable operation under multi-timescale disturbances and demonstrate the practical applicability of the proposed strategy for LVDC MGs.

Purpose This study aims to achieve accurate online monitoring of a DC-link capacitor’s equivalent series resistance (ESR) by overcoming the undesired coupling between the ESR and the parasitic inductance in the measurement path, thereby eliminating the reliance on offline characterization. Design/methodology/approach A self-calibrating technique is proposed that decouples these parameters in situ by leveraging the intrinsic dual-frequency ripple (twice the line frequency and the switching frequency) present on the DC bus as a natural excitation source. An overdetermined system model incorporating both ESR and parasitic inductance as unknown variables is established and solved via a recursive least squares algorithm. A standardized temperature normalization is further implemented to provide a high-fidelity health indicator. Findings Experimental validation on a 1.5-kW SiC inverter demonstrates that the proposed method accurately identifies the parasitic inductance and maintains the final ESR estimation error within ±5% across a wide range of load and temperature conditions (−10°C to 85°C). The results confirm the superior accuracy and robustness of the in situ multi-parameter identification approach. Originality/value This paper presents a novel approach that shifts the monitoring paradigm from simple impedance calculation to an in situ multi-parameter identification framework. By providing a self-calibrating capability without auxiliary hardware, the method enhances the reliability and maintenance efficiency of power electronic converters.

Purpose This paper aims to design a memristor-based associative memory neural network circuit with emotional overshadowing and congruent effects, considering overshadowing and recovery processes under multiple emotions. Design/methodology/approach The proposed system simulates both overshadowing and recovery under multiple emotional conditions and it mainly includes the following three parts The memory block can realize the learning and forgetting process in Pavlovian associative memory The emotion block can recognize different emotional stimuli which in turn produce different emotional outputs and return to normal when the stimuli disappear The feedback inhibition block can realize the overshadowing between positive music and negative music. Findings The memory block, the emotion block and the feedback inhibition block can work together to realize the functions of overshadowing and recovering from overshadowing under different emotions as well as the obstructing phenomenon caused by long-term overshadowing. Originality/value In this paper, the authors design a memristor-based associative memory neural network circuit with overshadowing and congruent effects to realize the overshadowing and recovery of different emotions. The designed circuit realizes the functions of memory generation and forgetting, as well as judgment of musical stimuli in different emotions, overshadowing and obstructing caused by long-term overshadowing, and recovery after overshadowing, individually.

Purpose The environmental monitoring system, using track inspection robots as the primary component, represents a novel approach to environmental monitoring. Currently, there is limited research on this technology. This study aims to explore the use of microelectronics integration technology to enhance the capabilities of the track inspection robot within the environmental monitoring system. Design/methodology/approach An integrated universal main controller was designed by using microelectronics integration technology and using ATmega2560 as the control core. The previously complex and large environmental control system was streamlined into a more efficient integrated design through micromotor integration technology, focusing on the track inspection robot. Subsequently, the overall performance of the environmental control system was evaluated. Findings After program optimization, the controller was implemented on the current pig house track inspection robot. In comparison to the initial control system, standby power consumption decreased by 78.89%, average operating power consumption decreased by 20.6%, average cost reduced by 38% and 40% of wiring space was saved. Originality/value The environmental monitoring system, using track inspection robots as the primary component, represents a novel approach to environmental monitoring. Currently, there is limited research on this technology. This study explores the use of microelectronics integration technology to enhance the capabilities of the track inspection robot within the environmental monitoring system.

Purpose This study aims to enhance the transient stability of renewable-dominated power systems by proposing a novel energy transfer control scheme for frequency-coupled hybrid energy storage devices (HESDs), thereby mitigating the application risks associated with their insufficient frequency regulation capability. Design/methodology/approach A coordinated virtual inertia control framework is developed for the frequency-coupled HESD. First, the conversion relationships between the stored energy in battery and capacitor, and the mechanical kinetic energy of synchronous generator (SG) are established. Second, the small disturbance model of a power system with virtual inertia is derived, and the impact of frequency-coupled HESD on frequency stability and damping characteristics is analyzed. Third, based on the mechanism analysis of system transient stability, a novel energy transfer control strategy adapted to the HESD is proposed. Findings It can be concluded that the proposed energy transfer control strategy effectively enhances the transient stability of power systems with high renewable penetration by sharing transient energy between the SG and HESD, which simultaneously suppresses frequency deviations and rotor angle oscillations. Originality/value Existing studies have examined energy conversion between storage and generators, yet systematic quantitative modeling of battery/capacitor-to-kinetic energy conversion remains unestablished. Although virtual inertia is widely discussed, the explicit small-signal modeling of frequency-coupled HESD and its damping impact mechanisms are still inadequately explored. In addition, the design of an energy transfer control strategy that integrates transient stability mechanism analysis for hybrid energy storage systems and achieves simultaneous suppression of both frequency deviations and rotor angle oscillations represents a novel contribution to the field.

Purpose This paper aims to present the development of a shunt hybrid active power filter control using a fair cost function-based diffusion adaptive filtering (FCDAF) method for achieving the solutions of current-related power quality issues, such as harmonics in source current, low power factor, reactive power necessity from the source and unbalanced source currents during faults. Design/methodology/approach The generation of reference currents from the distorted currents by extracting the fundamental component, thereby minimizing the harmonics, is the prime task performed by the proposed controller. Findings Simulations are performed to assess the performance of the proposed technique for different load operating conditions using MATLAB/Simulink software. A laboratory-level, experimental hardware prototype of the system is built using OPAL-RT (OP4510) simulator as the controller. The results from both simulation and experiment are validated, and a comparative performance analysis is made to appraise the efficacy of the proposed filtering method in resolving the aforementioned power quality issues. Originality/value The FCDAF method outperforms most of the existing methods, such as normalized least mean square, normalized least mean fourth and variable step size least mean square, in terms of computational complexity, convergence rate, robustness to impulsive interference environments and steady-state error.

Purpose The implementation and test of electronic circuit able to operate with significant negative delay remain an open challenge for design engineers. This study aims to design an innovative multistage low-pass (LP) type negative group delay (NGD) active circuit. The considered LP-NGD topology is constituted by RC-network. After the proof-of-concept (POC) design and simulation, a printed circuit board (PCB) of LP-NGD active topology prototype was fabricated. The LP-NGD PCB was tested to confirm the possibility to propagate arbitrary waveform signal. The time-advance measurement result enables to verify the simulation one. Design/methodology/approach After the NGD value, bandwidth choice and number of cells, this innovative design method of multi-stage LP-NGD circuit is established under the following phases: the first phase is the calculation of resistors and capacitors constituting the considered topology. The second phase is the schematic simulation of the LP-NGD POC in the frequency domain. In the third phase, the obtained LP-NGD POC must be optimized. In the fourth phase, the available R, C and operational amplifier are chosen the PCB prototype. In the last phase, the test signal must be chosen to demonstrate the output in time-advance. Findings An innovative design theory, including the analytical and algorithm, to determine the multistage RC-circuit parameters is established in function of targeted LP-NGD specifications. The validity of the multistage RC-circuit design theory is verified by the PCB prototype experimentation showing measurement of −0.3 s signal advance. Originality/value This research work originality is the analytical and routine algorithm design methodology of multistage LP-NGD electronic circuit. The transient result obtained by considering arbitrary waveform signal tested with a PCB prototype confirm the relevance of the developed multistage LP-NGD RC-circuit design.

Purpose Permanent magnet synchronous motors (PMSMs) require precise rotor position for optimal vector control. However, initial position errors arise from non-ideal factors like friction and cogging torque, creating a discrepancy between the actual and measured positions. This paper aims to analyze these errors and proposes a compensation strategy to improve performance. Design/methodology/approach To address this challenge, the authors first rigorously analyze the generation mechanism of initial position errors through theoretical modeling. And the authors investigate the influence of rotor position error on motor speed and motor losses. Furthermore, the authors analyze the magnitude of the error limit and its influencing factors. Subsequently, the authors develop a novel position-compensation-based control strategy. This method enable precise alignment of the rotor position before motor startup. The proposed position compensation method is validated through both high-fidelity simulations and experimental tests, comparing performance metrics against conventional compensation method. Findings The results demonstrate that the PMSM control system using the proposed rotor position compensation strategy has improved the motor speed response, significantly reduced the stator current amplitude at the same time, thereby achieving a substantial decrease in copper loss. Compared with conventional methods, it achieves a 10% increase in rotational speed and a reduction of more than 15% in current amplitude. Originality/value This study systematically clarifies the generation mechanism of initial position errors and their impact on system performance. Based on this, the proposed position compensation method effectively resolves the position error issues caused by non-ideal factors, achieving a coordinated optimization of control performance and energy efficiency and holds significant engineering application value.

Purpose Gallium nitride high electron mobility transistors (GaN HEMTs) are representative wide-bandgap semiconductor devices characterized by their superior high-frequency switching characteristics. This paper aims to review their modeling methods and drive control technologies, systematically summarize the research progress and predict the future development trends. Design/methodology/approach This paper first introduces the background and advantages of GaN HEMTs and then reviews four modeling methods: physical model, behavioral model, analytical model and hybrid model. It also summarizes their respective characteristics and application scopes. Furthermore, key drive control techniques are discussed in depth. Finally, the development trend of modeling technology is predicted by combining the characteristics of typical devices. Findings Switching modeling methods for GaN HEMTs have advanced to better address high-frequency and high-power application requirements. Each model type offers distinct advantages regarding accuracy, complexity and physical interpretability. Integrating appropriate drive control strategies further enhances system performance. Originality/value This paper summarizes four switching models for GaN HEMTs and compares their characteristics and applicable scenarios. Subsequently, it further explores the driving characteristics and key technologies of GaN HEMTs, including dead time control, segmented driving and level shifting techniques. Finally, future development trends are discussed in light of practical device effects, with a particular focus on multiphysics coupling, emerging artificial intelligence (AI) modeling and adaptive driving technologies.