With the renewable energy continuously access to the microgrid, the microgrid itself does not have the disadvantages of the inertia of the synchronous generator in the traditional grid is increasingly apparent, for which the generalized droop control (GDC) strategy is proposed. In the normal operation of the system, GDC has the advantages of large inertia and small active power overshoot, but when subjected to external frequency perturbations, the grid-supporting inverter with large virtual inertia is prone to large transient active power overshoot and oscillation. To address this problem, the article establishes small-signal models under different perturbations based on the GDC compared with the virtual synchronous generator (VSG) and further proposes two adaptive inertia control strategies: GDC adaptive inertia (GDCAI) and adaptive inertia for operation mode switching (AIOMS). By adjusting the virtual inertia appropriately, the rate of change of frequency (RoCoF) is maintained in the set range while improving the transient performance of the system, the methods of reduce-order of the system model and control parameter design is given, to reduce the frequency fluctuation while greatly reducing the active power overshoot and improving the response speed of the system. The effectiveness of the two control strategies is verified by MATLAB/Simulink simulation and StarSim hardware-in-the-loop (HIL) experiment.

In this parper we consider an Alpazur oscillator which consists of a Rayleigh-type oscillator and a DC power supply controlled by a switch that modifies the operating mode. The oscillator denotes some special phenomena in some parameter settings and are called chaos or bifurcation. In addition, we observe the behavior of this oscillator over a wide rage of parameter variation. Chaos theory tools such as, bifurcation, phase portrait, poincaré section and Matching Energy (ME) was examined in the analysis of dynamic of the system. Simulations were carried out using the 4th-order Runge-Kutta algoritm in Matlab. The results shows that Alpazur oscillator is sensitive to parameter variation and exhibts a wide range dynamics from fundamental periodicty to chaos.

The work elucidated in this scientific article presents a novel non-isolated high gain switched capacitor (HGSC) DC-DC converter engulfed for carbon neutral energy applications. A hybrid utilization of complementary switching approach switches enables simplified control and high voltage gain of HGSC even at low duty cycle owing to the switched capacitor along with boost inductors. Further, the proposed structure also features high efficacy, reduced voltage stress and current stress on semiconductor switching devices. The proposed HGSC DC-DC converter principle of operation along with the steady-state analysis and different switching stages were discussed in detail. Small signal analysis has been performed to analyze the stability of the proposed converter, whereas an averaging technique is performed to know its dynamics performance. Furthermore, the converter is thoroughly analyzed in terms of power losses. For comparing the practical efficiency of the designed converter, non-idealities voltage gain is derived. The efficiency of the proposed converter is validated practically and extensive performance comparison is carried out with other solutions in the literature. When a supply of input voltage 20 V feed into the proposed converter. It produces an output voltage of 140 V to 240 V output. A 200W laboratory proto model is developed; accordingly conducted extensive experimental analysis to validate the feasibility of the proposed HGSC DC-DC converter topology.

The double-line frequency ripple power exists inherently in single-phase power converters. To address this problem, active power decoupling technique (APD) is widely used. It diverts the ripple power into a small energy storage element through introducing passive and active power devices. This inevitably involves more voltage and current sensors for corresponding control, which raises the cost while decreasing reliability and power density. In this paper, a Lyapunov-based methodology is proposed to achieve APD control without adding any sensor. According to the designed controller laws, the practical decoupling capacitor voltage will converge to its reference. The decoupling voltage reference is given by taking into account buffering the double-line frequency ripple power. Afterwards, the robustness against parameter perturbations of the proposed method is discussed. Finally, the experimental results verify the feasibility of the proposed control strategy.

The long transmission distance in wireless power transmission(WPT) system will lead to a sharp decline in transmission efficiency, this paper presents a novel ortho-octagonal double helix metamaterial that can effectively enhance the transmission efficiency of WPT systems, theoretically derived and experimentally verified the enhancement of evanescent wave transmission by this metamaterial dielectric plate. A WPT simulation system operating at 10.78 MHz is constructed by HFSS software, and the effects of adding passive relay coils and different shapes of metamaterials on the transmission efficiency are comparatively investigated. Both simulation and experimental results show that the transmission efficiency of the WPT system can be improved to different degrees after inserting different shapes of metamaterials at the transceiver end of the system. When the transceiver coil spacing of the WPT system is greater than 22 cm, the effect of metamaterials on the system transmission efficiency enhancement shows an increasing and then decreasing trend as the distance increases. The positive octagonal metamaterial improves 12% over the circular metamaterial in the mid-range transmission distance due to its better magnetic coupling effect. When the transceiver coil spacing is 22 cm, the open-circuit voltage of the receiving coil after loading the metamaterial is stabilized to be enhanced by nearly 5 times, and it has the best effect at 30 cm, and the transmission efficiency is enhanced from 30% to 60%, which verifies the effective enhancement of the metamaterial on the transmission efficiency of the WPT system.

This paper proposes a fully integrated low dropout (LDO) regulator with gate-couple flipped voltage follower(GC-FVF). The proposed GC-FVF addresses the limited output swing issue of conventional PMOS FVF in LDOs while maintaining a low output impedance. Besides, this LDO introduces a cascode compensation loop, which, along with the low output impedance of GC-FVF, pushes the output pole far away from the unity-gain bandwidth under both light and heavy load conditions. Consequently, the LDO becomes a stable two-pole system, supporting a high loop gain of up to 100dB and significantly enhancing the load and line regulation. Key specifications include a preset output voltage of 1.8V, a minimum unregulated input voltage of 2V, a maximum output current of 100mA, a ground current of 32μA, and an active chip area of 260μm×180μm. Notably, this LDO achieves high load regulation of 4.8μV/mA and high line regulation of 13.8μV/V without the need for off-chip capacitors.

The demand for wireless power transfer (WPT) systems that can maintain a constant voltage output (CVO)characteristic is gradually increasing in some practical application areas of WPT, such as industrial power supplies. However, existing CVO-type systems are often limited by the parameter design of the loosely coupled transformer (LCT) and the configuration of the receiver side is not compact enough. Therefore, this paper proposes a strongly coupled system with CVO function composed of capacitor-inductor-capacitor-none (CLC-N) topology. The system’s primary side uses a CLC compensation, while the secondary side conforms to a minimalist design without the need for compensation components such as capacitors and inductors. The initial segment of the paper pertains to the discussion of the conditions required to satisfy both zero-phase-angle (ZPA) and CVO functionality of the suggested system. Subsequently, an in-depth approach to parameter design is outlined, accentuating that the output voltage remains unrestricted by the LCT’s parameters. Additionally, this paper examines the realization of zero-voltage switching (ZVS) within the suggested system, as well as the influence that variations in compensation components have on the CVO function. To underscore the benefits of the suggested CVO-type WPT system that employs CLC-N compensation, the paper presents a comparison with a range of other CVO-type WPT systems. Ultimately, an experimental prototype is fabricated to test the theoretical framework, and the results from these experiments confirm the feasibility of the suggested CVO-type WPT system based on CLC-N compensation.

This paper presents a shadow signal generator that produces square and triangular waveforms. The oscillator frequency can be changed using an external circuit (shadow oscillator). This method will make the conversion speed better than the conventional oscillators. The technique is based on utilizing an external circuit to modify the comparator’s tripping point. The circuit is built using widely available commercial integrated circuits, 1% accurate resistors, and DC supplies with a ±5V voltage. The recommended setup is suitable for instrumentation where the oscillation frequency is directly proportional to the variation in the resistance of the sensor. The functionality of the proposed design was confirmed by experimentation and simulation. The oscillation’s frequency can be changed to be nearly 10 times greater than its starting value, according to the results.

Despite the performed progressive research work, the interpretation of negative group delay (NGD) function remains not familiar to non-specialist design and fabrication circuit engineers. The functionality misunderstanding limits the NGD circuit applications compared to other classical electronic functions. The present paper is dealing on the design of tunable property circuit by operating with positive and negative delay behaviors. The topology of the tunable circuit by using low-pass (LP) type NGD one is described. The design formulas for calculating the circuit resistor and capacitor parameters from the desired delay are expressed. The design feasibility of the tunable circuit composed of LP-NGD cell and RC-circuit is validated with a proof-of-concept (PoC) implemented on a test board. Two different signals with pulse and arbitrary waveforms having tens-milliseconds duration were considered during the validation tests. As expected by tuning a varistor from 0.4 kΩ to 1 kΩ, the negative delay behavior varying from about -0.4 ms was verified thanks to the time-advanced effect due to the LP-NGD property. Then, the output signal delay was observed to become positive when the varistor is tuned from 1 kΩ to 3 kΩ.

This paper presents the development of an interleaved bidirectional DC-DC converter with single-phase high-frequency isolation associated with two different pulse width modulations (PWM), one for each power flow direction. The converter stages analysis, DC voltage gains expressions, and voltage/current stresses in CCM are presented. The proposed converter advantages are new modulation, the current ripple frequency and voltage in two ports is four times higher than the switching frequency, volume and weight reduction of passive elements, and balanced current distribution between the legs. Besides, the single-phase transformer that provides galvanic isolation between the DC bus and the battery or supercapacitor. An experimental prototype is implemented in the laboratory to validate the mathematical and theoretical analysis for both energy flow senses under the test conditions at converter-rated power 2.5kW, Low voltage side 180V, and high voltage side 380V.

Wireless power transfer (WPT) system in seawater exhibits distinct transmission characteristics from those in air due to the unique properties of seawater medium and the complexity of the seawater environment. In this paper, a 2-transmitter (2TX) and 1-receiver (1RX) WPT system in the frequency band of 350~550 kHz in seawater is observed. When the transfer distance is at midrange, the maximum load voltage point of the system is shifted from 460 kHz to 430 kHz compared to that in air, and the maximum transfer efficiency is 7 times of that in air. The system maintains a stable output voltage when the receiving coil is at different offsets. To grasp the influence mechanism of seawater on wireless power transfer, two new parameters, complex self-inductance and complex mutual inductance, are introduced into the circuit model to summarize the propagation of electromagnetic waves in attenuating medium, and the model is verified through experiments.

This paper introduces a new non-isolated double-input triple-output (DITO) high voltage gain DC-DC converter with a wide range of applications, including hybrid voltage source systems, solar home appliances, dc bus power distribution systems, and electrical vehicles (EV). The proposed DITO converter interfaces two hybrid voltage sources to supply three different output loads with varying voltage and power levels. Compared to conventional converters of the same type, the proposed DITO converter offers several advantages, including operation for all duty cycles, integration of hybrid energy sources to transfer power to multiple loads, high voltage conversion ratio for all three output ports, a higher ratio of total voltage gain to total components number, common grounded input and output DC ports, simultaneous DC voltage regulation of three output ports by tuning separate controlling parameters of duty cycles, an additional turn ratio of coupled inductors to increase the voltage gain of output ports, and medium voltage stress on switches. The proposed DITO converter utilizes a new single-switch single-coupled-inductor DC-DC structure, which is analyzed and verified through a prototype implementation for 25V and 30V input voltages and 210V, 330V, and 400V output voltages with a total power of 480W. The experimental results confirm the simulation results and theoretical analysis.

A document by Zisong Mo. Click on the document to view its contents.

Among the power inverters, modular multilevel converters (MMC) have gained popularity due to their advantages over conventional two-level inverters. Although the MMC utilizes more power switches than traditional inverters, the former exhibits notable benefits such as low total harmonic distortion, low switching losses with lower voltage stress, high power quality, reduced electromagnetic interface, and modularity with numerous degrees of freedom to synthesize output waveforms. Concerning the synthesized voltage quality, several low-frequency modulation techniques have been proposed to produce output voltage with low harmonic content. A particular case of study consisting of a three-phase even-level MMC inverter is taken as a benchmark to comparatively evaluate four methods for synthesizing high-quality output voltage. The employed techniques are ( i) selective harmonic elimination (SHE), ( ii) generalized SHE, ( iii) THD Voltage Minimization, and ( iv) Optimum Nearest Level Modulation, selected based on the phase and line-to-line output voltage THD. The model is formulated to compute the commutating angles to control the MMC submodules. Simulations show individual performance under the same operating conditions. A lab-scale prototype is built to corroborate the theoretical approach. The results allow the selection of the most convenient modulation technique based on the number of commutations and harmonic spectrum.

Brushless DC motor (BLDCM) is widely used in aerospace equipment. But the neuter port in conventional BLDCM windings could lead to torque ripples and low reliability. Each phase winding of the open winding BLDC is connected to an H-bridge inverter, and its phase voltage and phase current could be controlled independently, which has a certain fault tolerance. Firstly, the circuit topology and conduction mode of the open-winding brushless DC motor are introduced, and a Matlab simulation model is established according to the mathematical equation of the motor. Then, the operation characteristics of the open winding brushless DC motor with power device failure are analyzed, and the characteristics of two fault-tolerant control methods, compensation and reconstruction, are discussed. Finally, the open winding brushless DC motor and controller are processed, and the experimental platform is built to verify the operation characteristics of the open winding brushless DC motor with normal operation and compensation operation.

The on-chip extraction of dynamic information from a scene can be addressed with either frame-based CMOS vision, also called smart image sensors, or with dynamic vision sensors, also known as event cameras. When implemented with a pinned photodiode (PPD) as 4-transistor active pixel sensors (4T-APS) the former brings about the benefit of low temporal noise and dark current but without high dynamic range (HDR). The latter comes with the benefits of HDR and fast event detection rate at a low power consumption. The drawback is the background activity noise, which leads to additional hardware or algorithms to keep it low. In essence, the taxonomy of dynamic information extraction with image sensors is that of global shutter solutions and event cameras, each of which with their pros and cons. This paper digs in such differences and similarities focused on mismatch and noise through a global shutter 4T-APS implementation with local HDR incorporated in 180 nm CMOS technology vs conventional logarithmic event sensors found in the literature.

Power electronic circuits play an extremely important role in industrial systems. Parametric failure of components in these circuits are extremely prone to occur, which can easily evolve into catastrophic failures with time. Hence fault diagnosis of circuits can avoid catastrophic failures. In this paper, we propose a channel segmentation residual network (CSRN) for circuit fault diagnosis, in which Gram angular difference filed (GADF) is used to convert the original fault signal into a two-dimensional feature map for input into the CSRN. The channels of the input feature map are distinguished by selecting the main working channels through a channel segmentation mechanism and a Darwin selection mechanism for feature retention and deletion operations. The diagnostic performance of the proposed method is verified on the DC-DC circuit fault dataset, and the results show that the proposed CSRN achieves 97.92% fault classification accuracy for this circuit, which is 1.98%, 13.34% and 6.67% higher than other models, respectively.