Limited Output Power Research Articles

THz Wave Power Enhancement Using a Microstrip Line-Based Combiner Integrated with Arrayed UTC-PDs

Advancements in semiconductor devices, such as Uni-travelling-carrier photodiodes (UTC-PDs), have played a significant role in the development of Terahertz communication technology. However, the persistent challenge is the limited output power from a single UTC-PD required for practical transmission distances. To enhance the output power, we propose and demonstrate a novel Terahertz wave power combining technique using a photomixer device comprising two arrayed UTC-PDs monolithically integrated with a microstrip line-based 2 × 1 Wilkinson power combiner and a patch antenna on a Silicon Carbide (SiC) substrate at 300 GHz. When the two UTC-PDs are activated at photocurrents of 8 mA and 10 mA, the device exhibits a 7.3 dB increase in power relative to the power obtained when only the 8 mA UTC-PD is activated, and a 4.4 dB increase in power relative to the power obtained with the 10 mA UTC-PD. This implies that power can be enhanced by a factor of N2 if the photocurrent is multiplied by N. Additionally, we demonstrate that the UTC-PD output saturation depends on the space charge effect, which modulates the electric field in the depletion region and results from critical charge density of about 80 kA/cm2 for the device in this work.

A large-aperture, high-power ultrawideband radiation system with beam broadening capacity.

Due to the limited maximum output power of the pulsers based on avalanche transistors, high-power ultrawideband (UWB) radiation systems usually synthesize plenty of modules simultaneously to achieve a high peak effective potential (rEp). However, this would lead to an increased aperture size as well as a narrower beam, which would limit their applications in intentional electromagnetic interference fields. In this paper, a high-power UWB radiation system with beam broadening capacity is developed. To achieve beam broadening in the time domain, a power-law time delay distribution method is proposed and studied by simulation, and then the relative excitation time delays of the modules are optimized to achieve higher rEp and avoid beam splitting in the beam broadening mode. In order to avoid false triggering of the pulser elements when implementing the beam broadening, the mutual coupling effect in the system is analyzed and suppressed by employing onboard high-pass filters, since the mutual coupling effect is much more severe in the low-frequency range. Finally, a radiation system with 36 modules is developed. Measuring results indicate that in the high-rEp mode, the developed system could achieve a maximum effective potential rEp of 313.6kV and a maximum pulse-repetition-rate of 20kHz. In the beam broadening mode, its half-peak-power beam width in the H-plane is broadened from the original value of 3.9° to 7.9°, with a maximum rEp of 272.9kV. The polarization direction of the system could be flexibly adjusted by a built-in motor.

Damage growth characteristics on the exit surface of fused silica by the low-temporal coherence light irradiation

The growth of fused silica surface damage poses a high risk in operating high-power laser devices, with complex physical mechanisms related not only to the wavelength, pulse width, fluence of incident pulse lasers, but also to initial damage size and material properties. With low-temporal coherence light (LTCL) increasingly applied in high-power laser-driven inertial confinement fusion (ICF), LTCL-induced damage growth has become a bottleneck limiting output power improvements. This paper analyzes LTCL damage growth characteristics and mechanisms on fused silica surfaces, obtaining its damage growth coefficient and threshold. By analyzing chemical composition variation, electric field of initial damage, and comparing the damage growth threshold of artificial initial damage, the mechanism of surface damage growth is investigated. This research provides reliable information for estimating fused silica lifetime in high-power LTCL devices and contributes to understanding LTCL properties.

High-Coupled Magnetic-Levitation Hybrid Nanogenerator with Frequency Multiplication Effect for Wireless Water Level Alarm.

Hybrid nanogenerators (HNGs) represent a promising avenue for water energy harvesting, yet their commercial viability faces hurdles such as limited power output, poor coupling, and constrained operational lifespans. Here, a highly coupled triboelectric-electromagnetic magnetic-levitation hybrid nanogenerator (ML-HNG) is introduced that shows great potential for water energy harvesting. The ML-HNG fulfills the challenges of high power output, strong coupling, and long operational lifespans. During the contact-separation process of the triboelectric nanogenerator (TENG), the changing magnetic flux in the electromagnetic generator's coils generates a potential difference between the coils and Cu electrodes. The unique design of the ML-HNG employs a shared coil electrode configuration, which enhances the coupling without adding extra volume. This integration allows the ML-HNG to achieve multi-frequency vibrations and multiple output cycles per external longitudinal movement, a phenomenon known as the frequency multiplication effect. With an average power density of 1.69W m-3 in water, the ML-HNG provides continuous power for a thermo-hygrometer and can quickly drive a wireless water level alarm system within a minute. This groundbreaking hybrid nanogenerator design holds significant promise for the efficient and consistent harvesting of low-frequency ocean wave energy, marking a substantial advancement in blue energy technology.

Design, Analysis, and Wind Tunnel Evaluation of Novel Fabric-Covered Rotor Blades in Wind Energy Generation

This paper investigates the performance of a novel fabric-covered rotor blade. The study aims to address the need for cost-effective wind turbine blades by exploring the potential of textile-based materials. The research includes a comprehensive wind tunnel experiment to evaluate the aerodynamic response of the fabric-covered blade, compared to a traditional hard-shell blade. The experimental data are systematically processed and corrected for wind tunnel effects, providing valuable insights into the aerodynamic behavior of the novel blade. The results show that the fabric-covered blade, constructed from PTFE-coated fiberglass fabric, exhibits promising aerodynamic characteristics, with potential applications in reducing manufacturing expenses and enhancing power generation. The study concludes by proposing a novel control strategy leveraging the natural deformation of blades at high wind speeds, suggesting potential applications in limiting power output at high wind speeds. Overall, these findings contribute to the ongoing efforts in developing innovative and cost-efficient solutions for wind energy generation.

Wideband and low-spurious optical waveform generator for optically addressable quantum systems manipulation and control

Optical manipulation of quantum systems requires stable laser sources able to produce complex waveforms over a large frequency range. In the visible region, such waveforms can be generated using an acousto-optic modulator driven by an arbitrary waveform generator, but these suffer from a limited tuning range typically of a few tens of MHz. Visible-range electro-optic modulators are an alternative option offering a larger modulation bandwidth, however they have limited output power which drastically restricts the scalability of quantum applications. There is currently no architecture able to perform phase-stabilized waveforms over several GHz in the visible or near infrared region while providing sufficient optical power for quantum applications. Here we propose and develop a modulation and frequency conversion set-up able to deliver optical waveforms over a large frequency range, with a high spurious extinction ratio, scalable to the entire visible/near infrared region with high optical power. The optical waveforms are first generated at telecom wavelength and then converted to the emitter wavelength through a sum frequency generation process. By adapting the pump laser frequency, the optical waveforms can be tuned to interact with a broad range of optical quantum emitters or qubits such as alkali atoms, trapped ions, rare earth ions, or fluorescent defects in solid-state matrices. Using this architecture, we were able to detect and study a single erbium ion in a nanoparticle. We also generated high bandwidth signals at 606 nm, which would enable frequency multiplexing of on-demand read-out Pr3+:Y2SiO5 quantum memories.

Lasing from a Large-Area 2D Material Enabled by a Dual-Resonance Metasurface.

Semiconducting transition metal dichalcogenides (TMDs) have gained significant attention as a gain medium for nanolasers, owing to their unique ability to be easily placed and stacked on virtually any substrate. However, the atomically thin nature of the active material in existing TMD lasers and the limited size due to mechanical exfoliation presents a challenge, as their limited output power makes it difficult to distinguish between true laser operation and other "laser-like" phenomena. Here, we present room temperature lasing from a large-area tungsten disulfide (WS2) monolayer, grown by a wafer-scale chemical vapor deposition (CVD) technique. The monolayer is placed on a dual-resonance dielectric metasurface with a rectangular lattice designed to enhance both absorption and emission, resulting in an ultralow threshold operation (threshold well below 1 W/cm2). We provide a thorough study of the laser performance, paying special attention to directionality, output power, and spatial coherence. Notably, our lasers demonstrated a coherence length of over 30 μm, which is several times greater than what has been reported for 2D material lasers so far. Our realization of a single-mode laser from a CVD-grown monolayer presents exciting opportunities for integration and the development of real-world applications.

Evaluating the reliability of microgrids consisting of renewable energy sources using stochastic scheduling based on the data-driven uncertainty set

The paper addresses challenges arising from the unpredictable and probabilistic nature of wind speed and solar irradiance, leading to variable power production in renewable sources. Power imbalance issues in grids result from the difficulty in accurately estimating these variables. The study introduces an improved data-driven uncertainty set, utilizing a neural network trained with extensive historical data from a multi-microgrid system. This set efficiently identifies strong coupling and extracts characteristic scenarios, ensuring high reliability with a minimal number of scenes. The proposed probabilistic model, implemented in the coordination of pumped storage, wind, and solar power plants, incorporates energy limits and storage characteristics. A four-mode IEEE model for storage units allows quick response to system needs. Simulating storage unit states every hour, considering system load, output power, and energy limitations, optimizes power dispatch based on battery capacity. Additionally, the paper addresses the uncertainty in electric power demand in microgrids, proposing an improved data-driven uncertainty set obtained from a neural network. By eliminating unrealistic worst-case scenarios, the approach accurately captures system characteristics, maintaining high reliability while significantly reducing convergence time. The proposed uncertainty set is applied in a novel two-stage robust optimization dispatch model, transforming the optimization problem into a mixed-integer linear programming problem, and solving it using a column and constraint generation algorithm. Numerical case studies verify the feasibility and superiority of the proposed approach in terms of economy and convergence performance compared to existing robust optimization methods.

Theoretical Analysis of the Power Performance of a Monostable Galloping-Based Piezoelectric Energy Harvester

In the past few years, different kinds of structural nonlinearities, such as external magnetic interaction and multistable structures, have been introduced into galloping energy harvesters to enhance energy harvesting efficiency. However, since the galloping-based piezoelectric energy harvester (GPEH) is a self-excited system, the conventional impedance matching method that is widely used in vibration energy harvesters is no longer valid for it. Therefore, the power characteristics of the nonlinear GPEH are still an open question to be solved. To this end, this paper is motivated to derive the approximate analytical solution of a monostable galloping-based piezoelectric energy harvester through the harmonic balance method and impedance matching theory. The analytical maximum power, power limit, and critical electromechanical coupling are studied from the perspective of the influence of structural nonlinearity on the power performance. Firstly, the approximate analytical solutions of output power, power limit, optimal resistance, and critical electromechanical coupling coefficient are derived. The accuracy of the analytical solution is verified by numerical simulation. It is found that the influence of structural nonlinearity on the power characteristics of the nonlinear GPEH is quite different under different wind speeds. After that, the power characteristics of the system under different wind speeds and different coupling conditions are investigated. The results showed that the maximum power of the system can be increased by introducing stiffness nonlinearity under low wind speed and weakly coupled configuration. Even more, the system can be shifted into a strongly coupled system when the nonlinearity is enhanced to a certain level. Reasonable design of stiffness nonlinearity can effectively reduce the critical electromechanical coupling, which indicates that stiffness nonlinearity is a feasible and effective way to improve the power performance of low-speed wind energy harvesting.

The conceptual design of the high-efficiency 400 kW solid-state power station at 352 MHz for the European spallation source

Abstract This paper introduces an innovative conceptual design of a 400 kW solid-state power amplifier (SSPA) station and presents preliminary measurements for the key components. Recent advancements and benefits of solid-state technology have made the prospect of replacing vacuum tubes increasingly appealing. Historically, a significant challenge was the limited output power capacity of individual solid-state transistors, necessitating the integration of numerous units to generate high-power microwave signals in the range of hundreds of kilowatts. However, modern transistors capable of producing over 2 kW of output power have emerged, facilitating this transition. Another weak point was low power efficiency in high-power operating mode. The advanced rugged technology (ART) of solid-state devices enables the utilization of these transistors in nonlinear and switching operating classes, thereby enabling the creation of high-efficiency high-power amplifiers. In this conceptual design, 264 SSPA modules based on ART, each with a power output of 1.6 kW, are combined. The measurements revealed a single SSPA capable of delivering up to 2 kW output power with a power efficiency of 73% at frequency of 352 MHz. Due to the minimal losses during module combination and working SSPA in Class-C operation mode, the power efficiency of the station is expected to closely mirror that of a single module.

Fabrication and characterization of electrically conducting electrochemically synthesized polypyrrole-based enzymatic biofuel cell anode with biocompatible redox mediator vitamin K3

Enzymatic biofuel cells (EBFCs) hold tremendous potential to power biomedical devices, biosensors, and bioelectronics. Unlike conventional toxic batteries, these electrochemical devices are biocompatible, harnessing energy from physiological fluids and producing usable electrical energy. But the commercialization of EBFCs is limited by the low operational stability, limited power output and poor electron transport efficiency of the enzymatic electrodes. In this study, a novel bioanode exhibiting a high electron transfer ability and long-term stability was fabricated. For the preparation of the anode, surfactant-assisted polypyrrole (PPy) was electrochemically co-deposited on a platinum wire with the simultaneous entrapment of vitamin K3 (VK3) and GOx (glucose oxidase) in the PPy matrix. Herein, conducting PPy acts as an electron transfer enhancer and provides appropriate electrical communication between the active site of the enzyme glucose oxidase (GOx) and the electrode surface. Biocompatible redox mediator vitamin K3 was employed as an electron transfer mediator to shuttle electrons between the oxidized fuel glucose and surface of the electrode in the electrochemical cell. The electrical conductivity of PPy was measured using the four-probe technique of conductivity measurement of semiconductors. The morphological characterization of as-synthesized anode (PPy/CTAB/VK3/GOx) was performed by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical characterization was studied by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) techniques. It was observed that the room-temperature conductivity of PPy lies in the semiconducting range and it also shows good stability on exposure to laboratory air, making it a promising material to provide electrical contact. The study developed a bioanode producing a modest current density of 6.35 mA cm–2 in 20 mM glucose solution. The stability, current output and ease of manufacturing process of the electrode make it particularly suitable for employment in biofuel cell applications.

Improving EET kinetics and energy conversion efficiency of 3D hydrophilic composite hydrogel through 2D direction biofilm growth

The limited power output of microbial fuel cells (MFCs) has impeded their widespread adoption application. Thoughtful selection of a suitable anode material not only enhances extracellular electron transfer (EET) efficiency but also stimulates microbial adhesion and proliferation. Herein, a three-dimensional conductive polymer hydrogel MXene/(polypyrrole)-(polyacrylamide) (MPP) is proposed, which can enhance the power generation performance of the bioanode by promoting the enrichment of microorganisms in the two-dimensional direction. The integration of hydrogel molecular chains within the layers of MXene effectively inhibits the self-aggregation of MXene layers, thereby facilitating the formation of ion transport channels for expedited charge storage. As a result, the maximum power density increases from 3.12 W/m3 (CF) to 6.71 W/m3 (MPP-25), the protein content of MPP-25 bioanode (59.66 ± 2.39 mg/cm2) is 3.34 times higher than that of CF (17.85 ± 1.53 mg/cm2), and the exchange current density value increases from 0.06 mA/cm2 (CF) to 0.26 mA/cm2. Conductive hydrogels prepared by MXene as a modifier are a promising bioelectrocatalyst for high-performance MFCs.

Multipolar Photoconductive Antennas for THz Emission Driven by a Dual-Frequency Laser Based on Transverse Modes

Continuous-wave tunable photonics-based THz sources present limited output power due to the restricted input optical power accepted by photomixers, along with reduced radiation resulting from low paraxial field amplitude. Here, we investigate multipolar antenna designs to increase the available continuous-wave THz output power by incorporating more photomixers. For this purpose, the spatial structures of the optical and THz E-fields are designed to enhance THz power and radiation in the far field. Simulations of 2 to 4 dipole antennas are conducted, demonstrating an improvement in antenna gain compared to standard dipole antennas. This is in addition to a potential increase in THz power and radiation for photomixing applications. Such work also paves the way for functionalizing the spatial structure of THz light for advanced applications.

(Keynote) Technological Challenges and Emerging Device Architectures for Future Semiconductor Micro and Nanoelectronics

Semiconductor technology has known an exponential evolution in the last decades and is fully integrated in our everyday life. According to the Semiconductor Industry association (SIA) the global semiconductor industry sales reaches about US$ 700 billion in 2023, corresponding with a shipment of more than 1.2 trillion components. This necessitates implementation of many novel materials, advanced design concepts and new transistor structures.Increased device performance and reduced power consumption, while maintaining a good manufacturability and yield performance without penalizing the cost/function, are driving microelectronic research towards 3-nm technologies. A large variety of device architectures such as FinFETs, TFETs, negative capacitance, Gate-All-Around, nanowires (NWs), nanosheets (NSs) in both horizontal or vertical configurations, CFET and Forksheet structures are extensively investigated for both logic and analog/RF building blocks enabling System-on-Chip (SoC) applications.In addition to the huge progress achieved in silicon technology, heterogenous integration of Ge and III-V technologies on a silicon platform shows a strong potential, leading towards the on-chip integration of building blocks with different functionality. The fact that both Ge and III-V materials can be selectively grown on Si has strongly triggered the interest in heterogeneous integration.Wide bandgap materials such as GaN offer unique features for RF applications used in base stations for mobile communication, complementing the performance of Si devices suffering from limited output power. These materials can epitaxially be grown on Si substrates. One of the main challenges related to the hetero epitaxy of III-V materials on a Si substrate is the control of extended defects due to the lattice mismatch of the different materials. In recent years, there has been a strong increase in the commercial availability of GaN devices, although for certain applications there is a competition with SiC.Complex and dense SoC applications can be realized by 3D wafer stacking using Through-Silicon-Vias (TSV) for wafer-to-wafer bonding. The 3D integration results in a reduction of the RC product and interconnect length, a smaller form factor and enables vertical partitioning. Main challenges are the TSV process module itself (e.g. Cu via filling, mechanical stress, contamination, keep-out-zone), the wafer thinning and handling and the 3D stacking technology (stacking density, pitch, chip-to-chip interconnect etc.). Very promising results are obtained for monolithic sequential 3D (S3D) processing based on the processing of different tiers on top of each other. Difference can be made between transistor level (n- and pMOS), CMOS level (different standard cells in different tiers) and IP block level for the partitioning. In this way it is e.g. possible to process first CMOS circuits in the Si substrate and then further processing in a III-V layer on top. Benefits are related to an enhanced device density per chip area and a shorter interconnection length. A low cost less scalable tier can be processed on top of an expensive scalable tier as done in the case of logic-memory integration.Major trends in above mentioned process integration approaches are reviewed and technological challenges of some process modules and device structures highlighted.

Fluidisation of Thermochemical Energy Storage Materials: Degradation Assessment

ABSTRACT Composite zeolites impregnated with anhydrous salt particles are promising materials for use in domestic thermochemical energy storage (TCES), however they have limited power output. Fluidization has the potential to increase the mass and heat transfer of TCES systems. In this study, a composite TCES material of LiX zeolite impregnated with MgCl2 salt is produced. This material and a LiX zeolite batch are then fluidized at different gas velocities to study whether degradation of these particles occurs when fluidizing. Images of the particles after fluidizing are analyzed using a validated method utilizing microscope images and specialized software used to study whether fragmentation or abrasion have been induced by fluidization. Composite particles were found to have increased average diameter by 7%−8%, which could be due to imperfect dehydration of these particles after the impregnation process, but also due to observed salt conglomerates present on the surface of some particles. Overall, excess degradation was not found due to fluidization at any gas velocity. No mass loss was measured in any sample after fluidization, and no appreciable fragmentation was observed. The LiX zeolite and composite particles measured 0.6192 mm and 0.6799 mm prior to fluidization and measured 0.6405 mm and 0.7088 mm after fluidization. However, this change is not statistically significant, and it is shown that a change in diameter is unlikely. Despite this, some fines have been produced which were found to have an average diameter of 3.60 μm (σ = 1, ±2.34 μm), and as such present a hazard if inhaled.

Resonance provocation of improved energy orbit in bi-stable vibration energy harvesters for power enhancement

Bi-stable vibration energy harvesters are advantageous for a wide bandwidth in low frequency ranges, but are confronted with the issue of limited output power. Bi-stability traditionally contains two low- and high-energy orbits; however, this paper reports resonance provocation of the improved energy orbit, which is much higher than the traditional two energy orbits and can be utilized for power enhancement. Theoretically, the enhanced energy orbit is provoked due to an increase in the system’s kinetic energy, achieved by modifying the bi-stable potential energy function from quartic function to quadratic function to utilize the linear resonant restoring force. Experimental results demonstrate that the provocation of the improved energy orbit is frequency selective, and the root mean square voltage is increased by 63.6% in the upward sweep and 188.5% in the downward sweep. For optimal load, the improved energy orbit increases the maximal root mean square voltage by 2.10 times and the maximal average output power by 4.37 times. Meanwhile, the device’s bi-stable bandwidth remains almost unchanged. These results prove that the resonance provocation of the improved energy orbit can refine the power while not sacrificing bandwidth, which is a promising solution to the overall performance improvement for vibration energy harvesters.

Maximum Voltage Gain Tracking Algorithm for High-Efficiency of Two-Stage Induction Heating Systems Using Resonant Impedance Estimation

A boost power factor correction (PFC) circuit has replaced the diode rectifier to improve its poor power factor performance, low efficiency, and output power limitation for conventional induction heating (IH) applications. Accordingly, many studies have been conducted, but they considered only the efficiency of the boost PFC rather than the entire IH system, or their control and design were complicated. In this paper, an algorithm tracking the maximum voltage gain of the resonant network is proposed to improve the entire efficiency of the two-stage IH system based on an exact online resonant frequency estimation. It can make the resonant network operate at the maximum voltage gain point which can improve the efficiency of the series-resonant inverter (SRI) included in the IH system with low circulating current, the minimum switching frequency, and zero voltage switching (ZVS) capability. The proposed algorithm also induces the minimum output voltage of the boost PFC, which can reduce its switching losses and total harmonic distortion (THD). The validity of the proposed algorithm is experimentally verified using a 2.4-kW prototype IH system, including the boost PFC and the IH-SRI controlled by a digital signal processor (DSP).

Carbon‐based interface engineering and architecture design for high‐performance lithium metal anodes

AbstractMetallic lithium (Li) is considered the “Holy Grail” anode material for the next‐generation of Li batteries with high energy density owing to the extraordinary theoretical specific capacity and the lowest negative electrochemical potential. However, owing to inhomogeneous Li‐ion flux, Li anodes undergo uncontrollable Li deposition, leading to limited power output and practical applications. Carbon materials and their composites with controllable structures and properties have received extensive attention to guide the homogeneous growth of Li to achieve high‐performance Li anodes. In this review, the correlation between the behavior of Li anode and the properties of carbon materials is proposed. Subsequently, we review emerging strategies for rationally designing high‐performance Li anodes with carbon materials, including interface engineering (stabilizing solid electrolyte interphase layer and other functionalized interfacial layer) and architecture design of host carbon (constructing three‐dimension structure, preparing hollow structure, introducing lithiophilic sites, optimizing geometric effects, and compositing with Li). Based on the insights, some prospects on critical challenges and possible future research directions in this field are concluded. It is anticipated that further innovative works on the fundamental chemistry and theoretical research of Li anodes are needed.

Stability Guaranteed Active Noise Control: Algorithms and Applications

Stability of the controller, robust stability of the active noise control (ANC) system, and limited output power of the hardware control board or actuators are crucial issues for ANC applications. Violation of these requirements results in output saturation, and hence nonlinear distortion by overloading the actuators. As a consequence, noise reduction performance of an ANC system will be dramatically degraded. A novel frequency-weighted leaky filtered-x least-mean-square (FxLMS) algorithm is developed in this article to fulfill these requirements. The proposed algorithm is an improvement of the traditional leaky FxLMS algorithm, where a frequency-weighted matrix is designed to replace the corresponding scalar weight. The frequency-weighted matrix, which is achieved by solving a constrained optimization problem, consists of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\it N$</tex-math> </inline-formula> frequency-weighted factors. By the frequency-weighted factors, the frequency response of the control filter is only suppressed at specific frequencies where the requirements on stability and/or limited output power are violated. Thus, the proposed control algorithm achieves better noise reduction performance than the traditional leaky FxLMS algorithm, which unnecessarily suppresses the control filter at all the frequencies. Simulations and experiments are carried out in a duct ANC system to verify the effectiveness of the proposed algorithm for both the feedforward and feedback ANC systems.

Trajectory-Switching-Modulation-Based Fast Power Transient Control Strategy for a Bidirectional Hybrid Modular DC Transformer

The hybrid modular DC transformer (HMDCT) combining the series resonant dual active bridge (SR-DAB) and phase-shift dual active bridge (PS-DAB) has the advantages of high efficiency and bidirectional power regulation. However, due to the unregulated SR-DAB resonant tank inertia and limited PS-DAB output power, the dynamic response of HMDCT is slower than the pure PS-DAB based DC transformer, which could lead to a larger output overshoot. To address the problems, first, a novel trajectory-switching-modulation (TSM) method is proposed to control the SR-DAB resonant tank to track the desired state-trajectory rapidly by using SR-DAB switch-states. Compared with the conventional LLC trajectory control, TSM is more suitable for the SR-DAB in the bidirectional HMDCT because TSM is available under bidirectional power flow without changing the topology or increasing magnetizing losses. Then, a TSM based fast power transients control strategy is proposed to improve the bidirectional HMDCT dynamic performance by controlling the PS-DAB and SR-DAB simultaneously. Besides, PS-DAB current stress can also be reduced during the load transients. Experimental results show that the proposed strategy has better dynamic performance than the classic proportional-integral feedforward based strategy.