Low Power Loss Research Articles

Design and Performance Investigation of a Series Compensated Inductive Wireless Power Transfer System for Supplying a Low Power DC Load

In this study, a series compensated WPT system is presented for low power DC load applications. Series LC resonant circuits are applied for both transmitter and receiver sides of WPT system to reduce the impedance at a specified operation frequency, and thus, ensure low power losses. The operation frequency is chosen as 109 kHz for the series compensated WPT system. Then, the series resonant LC filter is designed according to the operation frequency and WPT rating values. In addition, the power electronics systems with their controller and operation principle are demonstrated in depth. To investigate the performance of the proposed system, a 100 W series compensated WPT model is designed and constructed in Matlab/Simulink enviroment. Different simulation results are provided to illustrate the performance of the proposed WPT model. The simulation results show the stable operation of the proposed system under the designed system parameters.

The Optimization of Microwave Field Characteristics for ODMR Measurement of Nitrogen-Vacancy Centers in Diamond

A typical solid-state quantum sensor can be developed based on negatively charged nitrogen-vacancy (NV−) centers in diamond. The electron spin state of NV− can be controlled and read at room temperature. Through optical detection magnetic resonance (ODMR) technology, temperature measurement can be achieved at the nanoscale. The key to ODMR technology is to apply microwave resonance to manipulate the electron spin state of the NV−. Therefore, the microwave field characteristics formed near the NV− have a crucial impact on the sensitivity of ODMR measurement. This article mainly focuses on the temperature situation in cellular applications and simulates the influence of structural parameters of double open loop resonant (DOLR) microwave antennas and broadband large-area (BLA) microwave antennas on the microwave field’s resonance frequency, quality factor Q, magnetic field strength, uniformity, etc. The parameters are optimized to have sufficient bandwidth, high signal-to-noise ratio, low power loss, and high magnetic field strength in the temperature range of 36 °C to 42.5 °C. Finally, the ODMR spectra are used for effect comparison, and the signal-to-noise ratio and Q values of the ODMR spectra are compared when using different antennas. We have provided an optimization method for the design of microwave antennas and it is concluded that the DOLR microwave antenna is more suitable for living cell temperature measurement in the future.

A novel controllable capacitor commutation based superconducting hybrid direct current breaker

Featuring low power loss and high reliability, voltage source converter medium voltage direct current (VSC-MVDC) systems have been widely employed for grid-tied renewable energy applications. To maintain high operational safety, circuit breakers are needed to isolate faulted powerlines by comprehensively considering response speed and installation cost. Research efforts have been put to realizing DC fault isolation by coordinating resistive type superconducting fault current limiter (R-SFCL) and integrated-gate-commutated-thyristor (IGCT) based hybrid DC circuit breaker. In this paper, a controllable current commutation based superconducting DC circuit breaker (CCCB-SDCCB) is proposed. By integrating R-SFCL with IGCT based hybrid DC circuit breakers, the current interrupting capacity can be greatly enlarged with the advantage of low cost and fast speed, and hence the overall cost for suppress large fault currents can be greatly reduced for MVDC systems. In addition, a new current injection circuit branch using H-bridge structure is designed to recycle the residual capacitor voltage from the previous fault stage to trigger the IGCTs without the capacitor pre-charging process. Simulation results show that the fault current can be successfully suppressed from 24.2 to 2.1 kA and fully interrupted within 4.11 ms by the proposed CCCB-SDCCB.

High-performance CeFeCo/FeSiAl soft magnetic composites for megahertz power devices

Soft magnetic composites (SMCs) play a crucial role in modern electronics and electrical devices, for which challenges remain in maintaining magnetic performance and reducing loss at megahertz (MHz) frequencies. Here, CeFeCo/FeSiAl@ polyurethane (PU) SMCs have been rationally designed with the simultaneous achievement of large relative permeability, high domain-wall resonance frequency, and low power loss. As a rare-earth soft magnetic alloy, the CeFeCo is promising for high-frequency applications due to its easy-plane anisotropy, whereas FeSiAl is advantageous with increased electrical resistivity as well as approaching-zero magnetocrystalline anisotropy and magnetostriction. Hot pressing has been adopted to achieve a dense and homogeneous distribution of CeFeCo and FeSiAl powders in the PU for reduced magnetic dilution and eddy current loss. The resultant SMCs exhibit optional soft magnetic performance with large relative permeability of 21.0, low power loss of 3677.5 kW·m−3 at 5 MHz, and high domain-wall resonance frequency of 386.1 MHz. As such this work provides insights into the design of high-frequency SMCs incorporating novel rare-earth soft magnetic alloys.

Research on Step-Down Aviation Three-Phase Power Factor Correction based on Machine Learning and Optimization Algorithm

Objectives: The study looks at power quality issues, such as phase imbalance, voltage sags, and power factor issues, in aircraft systems. It highlights how immediate power factor correction steps are required to avoid equipment longevity problems and boost system efficiency, which will ultimately improve the performance of the entire aviation system. Methodology: Using a variety of data sources, real-time data gathering, and machine learning approaches, this study focuses on data collecting and real-time monitoring in aviation systems. Predictive modeling, testing methods for data preparation and analysis, and optimization algorithms for capacitor bank size and placement are all included. Considerations for privacy and security are covered. Result: Salp Swarm Optimization and the Dragonfly Algorithm are used in the study to assess the ideal capacitor sizes and positions, which results in better voltage profiles and lower active power losses. Aviation systems benefit from improved power factor correction through the application of integrated machine learning and optimization, which promotes sustainability and energy efficiency. Conclusion: The study demonstrated the significance of power factor correction in aviation by successfully addressing power quality issues in aircraft electrical systems through the use of optimization algorithms for capacitor sizing and location.

The principle of magnetic flux switch

This paper introduces an innovative Magnetic Switch (MFS) designed to control and alter magnetic flux within energy system components, offering an alternative to conventional power electronic devices. The MFS comprises a low-current control coil, a control core, and a high-density magnetic flux-carrying main core combined with a main coil energy system. In this novel magnetic configuration, when a low-power current excites the control coil, the magnetic flux in the main core (supplied by the main coil) decreases to nearly zero. Conversely, when the control coil disconnects from the power source, the magnetic flux within the main core attains its maximum value. This operation positions the MFS as a groundbreaking concept within magnetic-based energy systems, akin to transistors in power electronics. The main outcomes of the MFS concept are that it can vary the magnetic flux of the main core in the large range, and it is a fast magnetic switch with a simple and low power loss control circuit and an independent control coil from the main coil. Analytical studies thoroughly elucidate the performance and advantages of this proposed magnetic switch, substantiated by Finite Element Method simulations and experimental prototype outcomes.

High Effective Permeability and Low Power Loss of FeSiAl/Al2O3/ZnO SMC for High Frequency Application

High Effective Permeability and Low Power Loss of FeSiAl/Al₂O₃/ZnO SMC for High Frequency Application

Improving Low-Frequency Digital Control in the Voltage Source Inverter for the UPS System

Today voltage source inverters (VSIs) operate with high switching frequencies (let us assume higher than 50 kHz) owing to the fast Si (Silicon) or SiC (Silicon Carbide) switching transistors. However, there are some applications, e.g., with slower switches (e.g., IGBT—Isolated Gate Bipolar Transistor) or when lower dynamic power losses are required when the switching frequency is low (let us assume about 10 kHz). The resonant frequency of the output filter is usually below 1 kHz. The measurements of Bode plots of the measurement traces of various microprocessor-controlled VSIs show that in this frequency range, the characteristics of these channels can be simply approximated through two or three switching periods delay. For the high switching frequency, it is not noticeable, but for the low frequency it can cause some oscillations in the output voltage. One of the solutions can be to use the predictor of the measured state variables based on the full-state Luenberger observer or the linear Kalman filter. Both solutions will be simulated in MATLAB/Simulink and the chosen one will be tested in the experimental VSI. The research aims to omit delays in the measurement channels for the low switching frequency by using the predictions for the measured state variables and finally increasing the gains of the controller to decrease the output voltage distortions.

Ultralow-loss soft magnetic composites with temperature-resistant and insulated Al2O3/SiO2 layers through pyrolysis

Soft magnetic composites (SMCs) with low power loss are urgently needed to meet the increasing demand for high frequency and miniaturized inductors and transformers. Ultrathin cladding with good insulation and high temperature resistance is the key to achieve low-loss SMCs. In this study, we used MQ silicon resin as precursor to produce in-situ grown Al2O3/SiO2 composite insulating layer in FeSiAl SMCs through pyrolysis process and high-temperature reaction. The morphologies, microstructures and compositions of the coatings on the surface were characterized by SEM, TEM, EDS, TG, XRD, FTIR and XPS, and the results show FeSiAl powders are evenly and entirely covered with an inner Al2O3 and outer SiO2 composite insulating layer. The results of powder resistivity show that the insulating layer still maintains very high resistance after annealing at 750 °C. The composite insulating layer had high resistivity and reduced eddy current loss, while the high temperature annealing process reduced stress and defects and resulted in low hysteresis loss. The best magnetic properties were obtained from samples coated with 2.0 wt% MQ and annealed at 750 °C, with an effective permeability of 76 and the lowest power loss of 72.2 mW/cm3 at 50 mT/100 kHz, 88.5 mW/cm3 at 100 mT/50 kHz and 304.1 mW/cm3 at 100 mT/100 kHz.

Probing the influence of V2O5 and SBZKN composite additives on the magnetic characteristics and power loss of low-temperature sintered NiCuZn ferrites

Soft magnetic ferrites with exceptional magnetic characteristics and low power loss are in continuous demand in both academia and industry. In this work, a series of Ni0.22Cu0.31Zn0.47Fe1.98O4 ferrites doped with 0.5 wt% V2O5 and different SiO2-B2O3-ZnO-K2CO3-Na2CO3 (SBZKN) contents were synthesized using a conventional solid-phase method under a low sintering temperature of 925 ℃. The crystal phase, density, microstructure, grain size distribution, magnetic characteristics and power loss of the NiCuZn ferrites were studies to elucidate the composition-structure-property relationship. The underlying mechanisms were also thoroughly analyzed. The results showed that all the samples had a single-crystalline phase and dense microstructure when sintered at 925 ℃. As the SBZKN content increased, the density, saturation magnetization (Ms), residual magnetization (Br), complex permeability and quality factor (Q factor) exhibited a varying trend that increased initially and then decreased, while the coercivity (Hc) and power loss (Pcv) showed the opposite trend. The highest values of density, Ms, Br, magnetic permeability and Q factor of NiCuZn ferrites, obtained at an SBZKN content of 0.3 wt%, were 5.121 g/cm3, 51.07 emu/g, 188.47 mT, 389.8 and 114.3, respectively, while the lowest Hc and Pcv were obtained. The analysis showed that these outstanding magnetic and power loss characteristics were attributed to the uniform distribution of grain size and densification of NiCuZn facilitated by V2O5 and SBZKN incorporation.

Design and Fabrication of Switched Reluctance Motor for Energy Efficient Operation by Minimizing Torque Ripple

Around the world, motor is consuming more than 40% of the total-generated electrical energy. Accordingly, energy efficient electrical drives are the needs of the hour. The Switched Reluctance Motor (SRM) is more energy efficient than other kinds. Since SRM has a rugged structure, it has inherent fault tolerance characteristics and is cost-effective than synchronous and induction machines. Nevertheless, the application of such a motor is limited due to low torque density, torque ripples and power losses because of control circuit. In this research work, the author proposed a novel-designed SRM, which is achieved by optimizing stator and rotor pole arc. Alongside, a novel control circuit, which has single transistor, is proposed. The modification of stator and rotor pole arcs assists in the reduction of the torque ripple. The stator pole arc is modified from 32 degree to 36 degree, and the rotor pole arc is modified from 30 degree to 28 degree. Thus, the torque ripple is reduced from 3.25 to 2.92 Nm, and thus, the useful torque is increased from 4.94 to 5.2 Nm. Furthermore, a single transistor switching device is used instead of the conventional one with four switches. Hence, energy loss on the control circuit is significantly reduced. From the experimental analysis, it is found that, with-pole-arc modified SRM has higher efficiency than the one without it.

Low-Frequency and Sub-Synchronous Power Oscillation Suppression and Analysis of Hybrid Line Commutated Converter for HVDC Grid

Building high-proportion renewable energy grid requires economical and reliable High Voltage Direct Current (HVDC) converters. Line Commutated Converter (LCC) is widely used because of its long transmission distance, low power loss, low manufacturing cost, and large transmission capacity, which modular multilevel converter (MMC) cannot achieve, but has commutation failure (CF) problems. Low-frequency and sub-synchronous power oscillation caused by CF will affect the safety of bulk power systems. This paper theoretically analyzes the power oscillation during CF and CF recovery, and then proposes a novel hybrid line commutated converter (H-LCC) based on integrated gate commutated thyristor (IGCT), which can effectively mitigate CF and suppress power oscillation. The principle of H-LCC suppressing power oscillation is analyzed. On this basis, the performance of LCC, MMC and H-LCC under the same fault conditions is compared by a simulation study, which proves that H-LCC can improve the security and stability of high-proportion renewable energy power systems.

Submilliwatt Silicon Nitride Thermo-Optic Modulator Operating at 532 nm

Optical phase control is essential for optical beam steering applications. The silicon nitride thermo-optic modulator generally suffers from high electrical power consumption. Microresonator and multipass structures could reduce the electrical power consumption of silicon nitride thermo-optic modulators, with the drawback of a narrow operating bandwidth and high insertion loss. We demonstrate a single-pass silicon nitride thermo-optic phase modulator at 532 nm with low insertion loss and low power consumption, achieving a π phase shift power consumption down to 0.63 mW in a Mach–Zehnder switch. The rise and fall time are around 1.07 ms and 0.67 ms, respectively.

Improved design of passive damping for single phase grid‐connected LCL filtered inverter considering impedance stability

AbstractGrid‐connected inverters with an inductor–capacitor–inductor (LCL) filter usually require the implementation of damping in the filter to suppress the resonance associated with the filter and hence ensure internal stability. The value for the damping resistor is commonly chosen as one‐third of the capacitive reactance at the resonance frequency of the LCL filter. However, this commonly‐used principle does not take into account the external stability of the inverter, i.e. the potential for an interaction between the inverter output impedance and the grid impedance. This work discusses a new design for the damping resistor to assure the external stability of the voltage source inverter as well as its internal stability. The analysis shows that the proposed design can ensure the external stability of the voltage source inverter with different grid impedances as well as robustness against the variations of the filter parameters while maintaining low power losses and an acceptable attenuation rate for high‐frequency harmonics. To validate the theoretical analysis, a 1 kW, 110 V laboratory prototype is implemented. The obtained results confirm the applicability of the proposed design approach.

Design considerations of series type hybrid circuit breaker (S‐HCB)

AbstractThe series‐type direct current (DC) hybrid circuit breaker (S‐HCB) concept was previously reported to offer better performance than solid‐state circuit breakers (SSCB) and hybrid circuit breakers (HCB). S‐HCB offers low conduction power loss like an HCB and ‐scale interruption time, which is even faster than an SSCB. It uses a pulse transformer to isolate the lower‐voltage high‐inductance power electronic circuit from the high‐voltage, low‐inductance main power loop. This paper provides analysis of the impact of the S‐HCB circuit components on the overall system performance and a scalable S‐HCB design guide for different DC system voltage and current ratings. In addition, system energy flow analysis is performed in the time domain to provide an understanding of how energy is delivered, dissipated, and released throughout the entire fault interruption process. The S‐HCB prototype was experimentally tested at 3 kV/30 A and 6 kV/150A with the results showing the interruption of the low fault current of 30 A and the high fault current of 150 A within 8 and maintaining the fault current at a near zero value for 300 to enable an arcless opening of a series mechanical switch. The key design challenges of S‐HCB at high voltage and high current ratings were discussed and possible solutions to mitigate those challenges were introduced.

Optimization of the Control Algorithm for an Active Bearing Support

This article presents a spindle system with an active bearing support for which the author proposed a control system based on a PID controller. This type of solution improves the mechanical properties of this spindle by changing the stiffness, which results in a wider range of permissible rotational speeds, lower power losses and an increased resistance to vibrations of the entire system. This work describes the mechanism of changing the bearing preload. During tests on a real test stand, the correct functioning of the preload control system was checked for various dynamic conditions. In this work, the author describes the controller used to work in a feedback system, explains how the settings for this controller were selected and their optimization. The assessment of the correct operation of the controller is based on minimizing the amplitude of forced vibrations for the front spindle end by actively controlling the preload of the bearings. This publication is intended to present one of the ways to solve the important problem of limiting the maximum values of the vibration amplitude in the spindle system for its wide range of operating conditions. It also shows how important its optimal settings are in control systems.

Synergetic effect of particle shape and multi-layer coating on the magnetic properties of FeSiAl-based soft magnetic composites

Gas atomization and multi-layer coating are widely used powder fabrication techniques to prepare soft magnetic composites (SMCs) utilized in high-power low-loss power electronics. However, the diverse morphologies of gas-atomized powders significantly impact coating effectiveness, subsequently influencing the soft magnetic properties of SMCs. Herein, FeSiAl-based SMCs with different particle shapes and a multi-layer coating of phosphate and heat-resistant silicone resin are prepared to explore the synergetic effects of particle shape and coating on magnetic performances. Compared with dumbbell-shaped powder, the spherical powder has a regular shape and strong flowability, resulting in a close-packing structure of the magnetic core. The spherical particle with a large specific surface area promotes efficient insulation coating effects. The dumbbell-shaped particles are potentially prone to cause pores and defects during the high-pressure compaction process, leading to poor dense packing and magnetic loss performance. With a similar average particle size, the magnetic core prepared by spherical powders exhibits a larger interface area, resulting in a greater demagnetizing field after phosphating passivation, thus significantly improving the DC-bias performance. The FeSiAl-based magnetic core prepared by spherical powders with 1.5 wt% phosphoric acid passivation has better magnetic loss and DC-bias properties than that by dumbbell-shaped powders, showing a stable permeability of 60.4, core loss of 286.2 mW/cm3 at 100 mT, 100 kHz, and DC bias characteristic of 49.1 % at a DC superposition field of 100 Oe.

Simulation on an Advanced Double-Sided Cooling Flip-Chip Packaging with Diamond Material for Gallium Oxide Devices.

Gallium oxide (Ga2O3) devices have shown remarkable potential for high-voltage, high-power, and low-loss power applications. However, thermal management of packaging for Ga2O3 devices becomes challenging due to the significant self-heating effect. In this paper, an advanced double-sided cooling flip-chip packaging structure for Ga2O3 devices was proposed and the overall packaging of Ga2O3 chips was researched by simulation in detail. The advanced double-sided cooling flip-chip packaging structure was formed by adding a layer of diamond material on top of the device based on the single-sided flip-chip structure. With a power density of 3.2 W/mm, it was observed that the maximum temperature of the Ga2O3 chip with the advanced double-sided cooling flip-chip packaging structure was 103 °C. Compared with traditional wire bonding packaging and single-sided cooling flip-chip packaging, the maximum temperature was reduced by about 12 °C and 7 °C, respectively. When the maximum temperature of the chip was controlled at 200 °C, the Ga2O3 chip with double-sided cooling packaging could reach a power density of 6.8 W/mm. Finally, by equipping the top of the package with additional water-cooling equipment, the maximum temperature was reduced to 186 °C. These findings highlight the effectiveness of the proposed flip-chip design with double-sided cooling in enhancing the heat dissipation capability of Ga2O3 chips, suggesting promising prospects for this advanced packaging structure.

Rehabilitation and Techno design of Distribution transformer and 11kV feeder of a radial distribution system

In any transmission and distribution system- the performance of that system mainly depends on voltage regulation and efficiency. Hence for the better operation of the system, it is required to maintain constant voltage regulation with good power factor and low power loss throughout the feeder. This can be achieved by using various methods. Out of those, placement of a capacitor bank at the densely loaded areas is the best-proven method compared to any other method. This research work considered the feeder-5 of the Al-Uwainath primary substation which was suffering from low voltage–poor regulation- problems. Here in this research modeled and analyzed 3 different techniques for rehabilitation to this low voltage, poor regulation, and power factor problem and recommended the most efficient method out of the three methods. As a part of this project simulated the same conditions of the site after collecting the data of the feeder from the site by using ETAP software and checked the performance by calculating its voltage regulation, power losses, and power factor in all three 3 different methods and recommended the most efficient method of feeder-5 rehabilitation by comparing the results of three methods with the exciting system.

WDM C-band four channel demultiplexer using cascaded multimode interference on SiN strip waveguide structure

Back reflection challenges significantly constrain the efficiency of optical communication networks employing dense wavelength division multiplexing (DWDM) technology, particularly those based on Silicon (Si) Multimode Interference (MMI) waveguides. To mitigate this limitation, we present a novel 1×4 optical demultiplexer design using MMI within a Silicon-Nitride (SiN) strip waveguide configuration, operating within the C-band spectrum. Our design was optimized using AI-enhanced RSoft-CAD simulations that combined the Beam Propagation Method (BPM) and Finite-Difference Time-Domain (FDTD) techniques, integrated with convolutional neural network (CNN) machine learning algorithms. The simulation results demonstrate that the proposed device efficiently transmits four channels with 10 nm spacing in the C-band, showing low power loss ranging from 1.98-2.35 dB, a broad bandwidth of 7.68-8.08 nm, and excellent crosstalk suppression between 20.8-23.4 dB. Leveraging the low refractive index of SiN, we achieve ultra-low back reflection of 40.58 dB without requiring specialized angled MMI designs, which are often necessary in Si-based MMI technology. Consequently, this SiN-based MMI demultiplexer provides an effective solution for DWDM systems, enabling high data transmission rates with minimal back reflection in optical communication networks.