Converter Modules Research Articles

A [92.4] FO4(1V), [53.71] Eu(1V) 4-bit absolute-value detector

With the development of modern computers, the integration of chips is getting higher and higher, and as the computing power increases, the energy consumption of chips is also increasing. Therefore, designing and optimizing low-latency and low-energy chips are the goals of many researchers today. At the same time, 4-bit absolute value detector are one of the most basic and important circuits for data storage and processing in chips. This paper designs a 4-bit absolute value detector circuit using Complementary Metal Oxide Semiconductor (CMOS) transistors that can take the absolute value of the input 4-bit signed number and compare it with the threshold value. And it includes the design of its absolute value conversion module and comparator module. By optimizing the circuit structure, the number of logic gates is reduced. By calculating the minimum delay on the critical path, logic gate size and other parameters, the power consumption of the circuit is reduced by adjusting the delay. In conclusion, this paper research can help further optimize the development of chip design industry.

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.

A Low Frequency Power Amplifier Design Based on Output CapacitorLess Circuit

This low-frequency power amplifier utilizes the AT89S51 microcontroller as the main control chip. The system can be divided into several modules: power amplification circuit module, pre-amplification module, band-stop filtering module, protection circuit module, volume control module, power supply voltage, AC voltage, and AC current testing module, A/D conversion module, power module, and single-chip microcomputer subsystem control module. We chose class AB audio power amplifiers. To ensure circuit stability and higher fidelity, we selected the TDA2030 integrated chip to build the OCL power amplifier circuit, preventing efficiency from being too low. Through the control of single-chip microcomputer subsystem, it can measure and display output power, the supply power of the DC power source, and overall efficiency. This system utilizes electronic switches connected with band-stop filters, with the band-stop frequency ranging from 40～60Hz.

A fast-response RBCOT buck converter with second-order differential and integrator compensation based on FVF

A second-order differential and integration circuit based on a flipped voltage follower (SDI-FVF) is proposed in the paper, providing compensation ripple for the buck convert with ripple-based constant on-time (RBCOT). Additionally, an adaptive conduction time module is designed which stabilizes the operating frequency of the converter in continuous conduction mode (CCM) and guarantees stable conduction time in discontinuous conduction mode (DCM). The proposed RBCOT buck convert has been designed using 180 nm process. It operates with an input voltage range of 2.5 V–5 V and an output voltage range of 0.8 V–5 V, accommodating a load current range of 0 A to 3 A. It operates at a frequency of 4 MHz, exhibiting an output ripple of 1.4 mV, achieving a peak efficiency of 91.5 %. The efficiency exceeds 85 % under a load current of 1 mA. The undershoot and overshoot voltage are only 0.13 mV and 7.1 mV with a load current variation rate of 3 A/μs.

A long-horizon move-blocking based direct power model predictive control for dynamic enhancement of DC microgrids

This research paper presents a novel long-horizon move-blocking based direct power model predictive control (DPMPC) strategy, uniquely designed to enhance the dynamic performance of boost converters in the grid-connected mode within DC microgrids. A precise dynamic model is developed considering a boost converter connected to a DC-link supplying constant power and resistive loads. To predict the system's dynamic behavior over an extended interval and enhance its performance in the presence of constant power loads, the long-horizon based finite control set model predictive control (FCS-MPC) method is introduced. To address the computational complexity associated with the conventional long-horizon DPMPC approach, a move-blocking (MB) strategy is incorporated into FCS-MPC, reducing the computational burden while improving the dynamic performance of the boost converter. Unlike recent studies that utilize DPMPC with short prediction interval, this paper presents evidence that a longer prediction interval is crucial for maintaining system stable and enhancing the dynamic response and also utilizing MB to make the control implementable in the real-time. The simulation results conducted using MATLAB/Simulink demonstrate the effective performance of the proposed strategy across various operating conditions of the boost converter. Experimental results further validate the strategy's capability to enhance the dynamic performance of the boost converter. Importantly, the experimental findings confirm the feasibility of implementing the proposed long-horizon move-blocking DPMPC strategy in real-time applications.

Wav2wav: Wave-to-Wave Voice Conversion

Voice conversion is the task of changing the speaker characteristics of input speech while preserving its linguistic content. It can be used in various areas, such as entertainment, medicine, and education. The quality of the converted speech is crucial for voice conversion algorithms to be useful in these various applications. Deep learning-based voice conversion algorithms, which have been showing promising results recently, generally consist of three modules: a feature extractor, feature converter, and vocoder. The feature extractor accepts the waveform as the input and extracts speech feature vectors for further processing. These speech feature vectors are later synthesized back into waveforms by the vocoder. The feature converter module performs the actual voice conversion; therefore, many previous studies separately focused on improving this module. These works combined the separately trained vocoder to synthesize the final waveform. Since the feature converter and the vocoder are trained independently, the output of the converter may not be compatible with the input of the vocoder, which causes performance degradation. Furthermore, most voice conversion algorithms utilize mel-spectrogram-based speech feature vectors without modification. These feature vectors have performed well in a variety of speech-processing areas but could be further optimized for voice conversion tasks. To address these problems, we propose a novel wave-to-wave (wav2wav) voice conversion method that integrates the feature extractor, the feature converter, and the vocoder into a single module and trains the system in an end-to-end manner. We evaluated the efficiency of the proposed method using the VCC2018 dataset.

Low Voltage Ride Through Control Strategy for a Two-Stage Grid-Tied Solar Photovoltaic System with Grid Faults

This paper investigates a low voltage ride-through (LVRT) control strategy for a two-stage grid-tied solar photovoltaic (SPV) system with line-to-ground (L-G) and double line-to-ground (L-L-G) faults. A proportional resonant (PR) controller controls the SPV inverter based on classical and reactive power oscillation-based reference current generating techniques. The proposed method injects reactive power as an ancillary service to provide voltage support and prevent power outages, reduces the DC component injection into the grid currents, and finally injects sinusoidal currents into the grid, avoid voltage oscillations in the DC-link and limit the inverter current by operating the boost converter in non-MPPT mode during L-G & L-LG faults. Experimental results for reference current generation using classical method and proposed method are compared to highlight the proposed controller’s ability to maintain power quality during faults.

Zero-magnetic-field operation of ordinary-Nernst-effect-based transverse thermoelectric module using embedded permanent magnets

Zero-magnetic-field operation of ordinary-Nernst-effect-based transverse thermoelectric module using embedded permanent magnets

GaN based isolated bidirectional multiport DC-DC converter for electric vehicle charging

The research work proposes an efficient Gallium Nitride (GaN) based isolated bidirectional DC-DC (IBDC)-Triple Active Bridge (TAB) based multi-port converter (MPC) for electric vehicle (EV) charging. The developed GaN IBDC-TAB based MPC utilizes fewer components compared to conventional IBDC charging system if designed for two output ports. The proposed GaN IBDC-TAB based MPC incorporates one input port, Port 1, and two output ports, Port 2 and Port 3 for Level-1 and Level-2 EV charging systems respectively. In addition, the developed GaN IBDC-TAB can be operated in Single Active Bridge (SAB), and Dual Active Bridge (DAB) modes as per operational requirements. A 12 kW GaN IBDC-TAB based MPC is designed and evaluated using LTspice XVII software. In TAB mode of operation, Port 2 delivers 1.5 kW, and Port 3 delivers 10.6 kW. The maximum efficiency of 98.87 % is obtained in simulation for the MPC converter in TAB mode. For experimental validation, an approximately 1 kW prototype is presented with Port 1, Port 2, and Port 3 voltages as 230 V, 120 V, and 200 V respectively with an operating frequency of 100 kHz. The single-phase-shift control strategy is implemented for controlling the transmitted power in the developed GaN IBDC-TAB based MPC.

Composite Duty Modulation of Dual Active Bridge Converters to Minimize Output Voltage Ripples and Inductor RMS Currents

Composite Duty Modulation of Dual Active Bridge Converters to Minimize Output Voltage Ripples and Inductor RMS Currents

Optimal Pulse Width Modulation of Three-Level Converters With Reduced Common-Mode Voltage

Optimal Pulse Width Modulation of Three-Level Converters With Reduced Common-Mode Voltage

Design and Implementation of Robust H∞ Control for Improving Disturbance Rejection of Grid-Connected Three-Phase PWM Rectifiers

In response to the high performance requirements of pulse width modulation (PWM) converters in grid-connected power systems, H-Infinity (H∞) control has attracted significant research interest due to its robustness against parameter variations and external disturbances. In this work, an advanced robust H∞ control is proposed for a grid-connected three-phase PWM rectifier. A two-level control strategy is adopted, where cascaded H∞ controllers are designed to simultaneously regulate the DC bus voltage and input currents even under load disturbances and non-ideal grid conditions. As a result, unit power factor, stable DC bus voltage, and sinusoidal input currents with lower harmonics can be accurately achieved. The design methodology and stability of the proposed controller are verified through a comprehensive analysis. Simulation tests and experimental implementation on a dSPACE 1103 board demonstrate that the proposed control scheme can effectively enhance disturbance rejection performance under various operating conditions.

Research on Overload Early Warning System for Railcars

Railcars are prone to suffer from overloading problems during its operation, which seriously affects the service life of railcars and rails, while posing a serious potential safety hazard. This paper In this paper, the weight of the car load is calculated by installation of a gravity sensor on the railcar and collection of the data from the gravity sensor through applying the A/D conversion module of the MCU. The overloading warning function of railcars is realized according to the drive alarm indicator of overloading information, and displaying the overloading information on the liquid crystal display screen.

Neural Network Quadrature Signal Generator-Based Virtual Flux Estimation for Predictive Control of PWM Converters

In this paper, a frequency-adaptive neural network-based virtual flux (FANN-VF) estimator is developed for sensorless control of a pulse-width modulation converter under unbalanced and distorted grid conditions. This method exploits two parallel FANNs configured as quadrature signal generators. The VF fundamental positive and negative sequence components (PNSCs) are inherently separated in the estimator without employing any cascaded filters. A frequency-locked loop is introduced to accurately track the frequency variations. The estimated VF PNSCs are directly exploited to compute the power references in VF-based predictive direct power control scheme. The developed strategy ensures constant active power and sinusoidal current waveforms under nonideal grid conditions. Simulation and experimental tests are performed to verify the effectiveness of the proposed method.

An Improved Bi-Switch Flyback Converter with Loss Analysis for Active Cell Balancing of the Lithium-Ion Battery String

This paper focuses on the active cell balancing of lithium-ion battery packs. An improved single-input, multioutput, bi-switch flyback converter was proposed to achieve effective balancing. The proposed topology simplifies the control logic by utilising a single MOSFET switch for energy transfer and two complementary pulses to control the cell-selecting switches. The proposed topology can decrease the number of switching devices as well as the size and cost of the system. The bi-switch flyback converter eliminates the need for a separate buffer circuit to minimise leakage and electromagnetic inductance. Losses and energy efficiency were analysed at each end of the proposed topology. The appropriate MATLAB simulations investigated the balancing characteristics of various state of charge (SOC) imbalances. A comparison is made between the balancing speed and energy transfer efficiency of the proposed topology and a conventional topology that employs a multi-input and multi-output flyback converter in a static mode. The results of the MATLAB simulation were validated by the OPAL-RT (OP5700) real-time simulator. The balancing data of the proposed topology were compared using MATLAB simulation and real-time simulation. This work may reduce the time required to assemble and commission the hardware for the proposed topology’s real-time implementation.

Frequency converting and digital modulation of light derived from lanthanide for signal encoding and logic computing

AbstractModulation of light underpins a central part of modern optoelectronics. Conventional optical modulators based on refractive‐index and absorption variation in the presence of an electric field serve as the workhorse for diverse photonic technologies. However, these approaches based on electro‐refraction or electro‐absorption effect impose limitations on frequency converting and signal amplification. Lanthanide‐activated phosphors offer a promising platform for nonlinear frequency conversion with an abundant spectrum. Here, we propose a novel approach to achieve frequency conversion and digital modulation of light signal by coupling lanthanide luminescence with an electrically responsive ferroelectric host. The technological benefits of such paradigm‐shifting solution are highlighted by demonstrating a quasi‐continuous and enhancement of the lanthanide luminescence. The ability to locally manipulate light emission can convert digital information signals into visible waveforms, and visualize electrical logic and arithmetic operations. The proof‐of‐concept device exhibits perspectives for developing light‐compatible logic functions. These results pave the way to design more controllable lanthanide photonics with desired opto‐electronic coupling.image

Protein-to-DNA Converter with High Signal Gain.

DNA isothermal amplification techniques have been applied extensively for evaluating nucleic acid inputs but cannot be implemented directly on other types of biomolecules. In this work, we designed a proximity activation mechanism that converts protein input into DNA barcodes for the DNA exponential amplification reaction, which we termed PEAR. Several design parameters were identified and experimentally verified, which included the choice of enzymes, sequences of proximity probes and template strand via the NUPACK design tool, and the implementation of a hairpin lock on the proximity probe structure. Our PEAR system was surprisingly more robust against nonspecific DNA amplification, which is a major challenge faced in existing formats of the DNA-based exponential amplification reaction. The as-designed PEAR exhibited good target responsiveness for three protein models with a dynamic range of 4-5 orders of magnitude down to femtomolar input concentration. Overall, our proposed protein-to-DNA converter module led to the development of a stable and robust configuration of the DNA exponential amplification reaction to achieve high signal gain. We foresee this enabling the use of protein inputs for more complex molecular evaluation as well as ultrasensitive protein detection.

Effects of Fuel Flow and Airflow Swirl on Thermal Performance of a Miniature-Scale Combustor for Direct Energy Conversion Systems

Micropower generation and micropropulsion are two emerging fields where micro- and miniature-scale combustors are anticipated to play a significant role. Today, there is a growing interest in combustion-based direct energy conversion modules such as thermoelectric and thermophotovoltaic micropower generators. In this study, the effects of swirl addition to fuel flow and airflow on combustor operational envelope, flame blowout limit, combustion efficiency, exhaust gas temperature, mean outer wall temperature, emitter efficiency, and normalized temperature standard deviation of a miniature-scale (mesoscale) combustor are studied under various equivalence ratios. The findings demonstrate that swirling flows improve the flame blowout limit and operational envelope of the combustor; however, this improvement is more significant for airflow swirl. Besides simultaneous swirling flows of fuel and air result in the highest blowout limit. Additionally, it has been shown that swirl addition improves combustion efficiency and causes a significant amount of heat to be generated, which raises the temperature of the exhaust gas, the mean outer wall temperature, and the emitter efficiency. Furthermore, mean outer wall temperature and emitter efficiency have the highest values for simultaneous swirling flows of fuel and air. It is also observed that increasing the fuel flow swirl number generally lessens the normalized temperature standard deviation (NTSD) and consequently improves the combustor wall temperature uniformity, while for the airflow swirl case, a swirler with 30° vane angle for airstream has a lower NTSD than a 45° vane angle swirler. The results obtained in this study provide useful information for designing a combustion-based direct energy conversion module.

ДОСЛІДЖЕННЯ ЕЛЕКТРОМАГНІТНИХ ТА МЕХАНІЧНИХ ПРОЦЕСІВ АСИНХРОННО-СИНХРОННОГО ЕЛЕКТРОМЕХАНІЧНОГО ПЕРЕТВОРЮВАЧА В РЕЖИМІ НЕРОБОЧОГО ХОДУ

A two-dimensional circuit-field model of non-stationary electromagnetic and mechanical processes of an induction-synchronous electromechanical converter has been developed. It allows establishing the relationship between electro-magnetic processes in the circuit and 2D-field parts of the model, taking into account the features of the construction of its armature and rotor windings through their schematic implementation, and ensuring switching with elements of con-ventional and semiconductor power systems. Electromagnetic and mechanical processes in idle mode have been inves-tigated using numerical modeling methods, considering the combined interaction of the coupled induction and synchro-nous parts in a single active part of the electromechanical converters. The presence of self-synchronization properties for induction -synchronous electromechanical converters has been demonstrated, wherein asynchronous starting is provided with subsequent synchronization of its rotor into synchronism in idle mode without excitation, and the condi-tions for their occurrence are explained. The relationships between the idle current and excitation current have been established, determining the operation of the synchronous part of the induction-synchronous electromechanical con-verter in underexcited, normally excited, and overexcited modes. It has been proven that in underexcited and normally excited modes, its synchronous part operates as a reactive power compensator, while in the overexcited mode, it oper-ates as a generator. Experimental studies confirm the adequacy and accuracy of numerical implementation, as well as the correspondence to electromagnetic processes during the operation of the induction-synchronous electromechanical converter in idle mode. References 14, figures 11.

Topology and Hybrid Modulation of Six-Level Switched-Capacitor HC Converter With Improved DC-Link Capacitor Voltage Balancing

Topology and Hybrid Modulation of Six-Level Switched-Capacitor HC Converter With Improved DC-Link Capacitor Voltage Balancing