Capacitor Motor Research Articles

A high-efficiency pre-lithiation strategy for Li-ion capacitor achieved by the synergistic effect of pre-lithiation and solid electrolyte interface film modification

The cathodic pre-lithiation process, currently considered the most feasible resolution to address the irreversible depletion of Li+ in dual carbon-based lithium-ion capacitors (LICs), encounters obstacles in widespread adoption due to its substantial dosage requirement, rising decomposition potential and the damage related to its decomposition residues. Hence, in this study, the successful utilization of Li2NiO2 for LIC pre-lithiation is accomplished, leveraging the synergistic effect between Li2NiO2 and lithium difluoro oxalate borate (LiDFOB). It's noteworthy that the full capacitor, entirely composed of commercial materials (activated carbon/hard carbon) and supplemented with 20 wt% LNO +2 wt% LiDFOB, exhibits remarkable energy densities of 98.53 Wh kg−1 at a power density of 31 W kg−1 and 19 Wh kg−1 at a power density of 4.65 kW kg−1. Moreover, the full capacitor displays commendable performance, demonstrating superior capacitive behavior and excellent high-current cycling proficiency. Besides, electrochemical evaluations and structural analyses unveil that LiDFOB, via solid electrolyte interface (SEI) modification, enhances the utilization of Li+ sourced from Li2NiO2 thus avoiding the abuse of pre-lithiation reagents, while the LNO decomposition products contribute substantially to additional capacitance. The synergistic effect of pre-lithiation reagent and SEI modification underpin the outstanding performance witnessed in the full capacitor.

Power quality improvement of PWM AC Chopper fed capacitor run induction motor using BFO, PSO and CSO Algorithm

This paper exhibits performance enhancement of PWM AC chopper fed capacitor run induction motor by using optimization algorithm. The PWM AC chopper utilizes enhanced asymmetrical pulse width modulation technique by incorporating four pulses in quarter cycle. The switching instants are obtained optimally by bacteria foraging optimization, particle swarm optimization and cuckoo search optimization algorithm. The power quality parameters considered in this paper are total harmonic distortion of current, total harmonic distortion of voltage, power factor and efficiency. The simulation result shows that proposed algorithm shows better performance compared to other optimization techniques.

Design and analysis of solitary AC–AC converter using reduced components for efficient power generation system

Considering different applications that require varied power and voltage conversion levels between AC grids and AC loads, AC–AC power conversion between AC grids has become an inevitable technology of energy management systems. An isolated converter for performing AC-to-AC transmission is proposed with minimal components for reduced losses and enhanced system efficiency. Single-phase direct buck-boost AC to AC converter with minimum components constituted with two dual IGBT control units (IGBT 1–IGBT 4), inductor (Lf), and capacitor (Cf) is proposed in this work. The MATLAB/Simulink platform is used to provide in-depth analysis of the circuit and components along with the design guidelines, and simulation outcomes of this proposed model. The voltage gains of G = 2.13, power factor of 0.97, and overall efficiency of 98% are achieved in the proposed system with minimum components of 4 switches, 2 conductors, and 1 capacitor and inductor respectively. The obtained results are compared with existing technology to evaluate the proposed system.

Fabrication of MnO2@Porous Carbons with High Energy and Power Density and Their Application in Supercapacitors

MnO2@PCs (porous carbons) exhibiting high energy and power density are utilized as supercapacitor electrodes and prepared by impregnating porous carbons (PCs) derived from coal tar pitch (CTP) with KMnO4 as the manganese source. This study systematically investigates the impact of MnO2 loading on the microstructure and electrochemical performance in sample. It is found that the specific surface areas (SSA) of all MnO2@PCs significantly reduced compared to that of the PCs 2789 m2 g−1. The suggested mechanism might be a combination of the energy storage mechanism of dual layer capacitors with pseudo‐capacitance due to redox reactions of MnO2. Notably, MnO2@PCs‐0.0075 exhibits a maximum SSA of 1454.62 m2 g−1. Its specific capacitance reached 561 F g−1 at 0.5 A g−1, while the capacitance of the PCs increased by 81.5% to 309 F g−1. Remarkably, the Coulombic efficiency remained at 100%. The power density and energy density are determined in a two‐electrode test system to be 0.5 kW kg−1 and 58.01 Wh kg−1, respectively, at 0.5 A g−1. Concluding from these results and related literature, the MnO2 content significantly influences the electrochemical performance, suggesting that MnO2@PCs‐0.0075 could be a promising supercapacitor (SC) electrode material, provided its capacitance retention is enhanced.

Design and Experimental Analysis of an Operational Amplifier Circuit-Based Mechatronic Semiactive Inerter

A novel mechatronic semi-active inerter (MSAI) by using an operational amplifier (OPA) circuit-based adjustable capacitor (OPA-CC) is proposed in this study to address the realization challenge of fast-responding semi-active inerters. The fast-responding ability, inertance-directly controlled capability, and sensor-less regulation characteristic are distinctive advantages of the proposed MSAI. To implement a pure controlled capacitor and a pure capacitive motor load (the internal resistance of the motor is canceled), two different types of OPA circuits are designed. Tuned inerter damper (TID) and tuned viscous mass damper (TVMD), as two typical MSAI-based configurations, are established and tested. It is found that the proposed MSAI can modify the inertance quickly (in the microsecond time scale) and reliably, and good congruence between theoretical and experimental results is obtained.

Improvised Freon Extractor as an Innovative Trainer

The decade of the 1990's has been a challenging time for the Heating, Ventilation, Air Conditioning, and Refrigeration (HVAC&R) industry worldwide. Due to its vital role in the destruction of the stratospheric ozone layer, provisions of the Montreal Protocol and its various amendments required the complete phase-out of chlorine-containing refrigerant such as chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). Appliances such as window type air-conditioners, motor vehicle air-conditioners, and refrigerators, rely on ozone depleting refrigerants and their substitutes. In this case, the regulation of the Environmental Protection Agency (EPA) which prohibits the venting of refrigerants compounds to the atmosphere must be followed. Along this line of concern, educational institutions need to be aware of this technological gap specifically in developing programs in Heating, Ventilation, Air-conditioning and Refrigeration for environmental protection against incorrect disposal of refrigerant. The aim of this study was to develop an Improvised Freon Extractor as an Innovative Trainer to help students and instructors in the Bachelor of Industrial Technology and
 Bachelor of Science in Mechanical Engineering courses in their effective teaching-learning of lessons in Refrigeration and Air-conditioning subjects. The results of the study revealed that the developed innovative trainer contains the following parts: electrical parts - includes the dual capacitor, banana plug, compressor, fan motor, air swing motor, air swing motor switch, thermostat switch, and selector switch; nonelectrical parts - frame housing, frame cover, suction and discharge valve, caster wheels, filter receiver drier assembly and condenser. The Improvised Freon Extractor as an Innovative Trainer was also found to be suitable to serve as an alternative learning material that assists the learning of Refrigeration and Air-conditioning subjects in the Bachelor of Industrial Technology and Bachelor of Science in Mechanical Engineering courses

ИССЛЕДОВАНИЕ МАГНИТНОГО ПОЛЯ ОДНОФАЗНЫХ АСИНХРОННЫХ ДВИГАТЕЛЕЙ

Induction capacitor motors are widely used in electric drive systems of various industrial and domestic mechanisms. Every year the scope of use of these machines continues to expand, both in new areas of technology and as a replacement for more complex el

Phytic acid mediated N, P co-doped hierarchical porous carbon with boosting capacitive storage for dual carbon lithium-ion capacitor

Lithium-ion capacitors (LICs) merged the energy characteristic of lithium-ion batteries and power characteristic of supercapacitors have aroused intensive attention. Nevertheless, the low capacity of capacitor-type cathode confines the development of LICs. Herein, an economic and efficient approach is developed to fabricate nitrogen and phosphorus co-doped hierarchical porous carbon (NP-HPC) by carbonizing cross-linked phytic acid and poly pyrrole/aniline precursor (PACP), in which phytic acid acts not only as a chemical crosslinker to regulate the precursor structure, but also a phosphorus source for dopant, thus providing more active sites for Li storage and enhancing structural stability. As-prepared NP-HPC cathode with enlarged specific surface area (∼2750 m2 g−1) and more micropores (∼1.410 nm) delivered a high specific capacity of 89 mAh g−1, with an ultrahigh capacity retention of 88.6% after 10000 cycles at 1.0 A g−1. DFT calculations demonstrated the co-dopant of N and P atoms synergistically improve the Li+ adsorption energy and electrochemical stability. More importantly, the assembled dual carbon LICs employing homologous NP-HPC and N, P co-doped spherical carbon (NP-SC) electrodes from the same precursor exhibit a maximum energy density of 121 Wh kg−1 at a power density of 92 W kg−1, with long-term cycling stability over 3000 cycles at 1 A g−1 with 80.2% retention.

Capacitance-based absolute pressure gauge for beamline vacuum measurement applications

For low-pressure measurements, capacitance diaphragm-based absolute pressure gauges are used owing to their high accuracy, media independence, and simplistic design. Catering to the general requirements of synchrotron beamline vacuum measurements, a capacitance diaphragm-based absolute pressure gauge is designed, developed, tested, and calibrated. The sensor is having electrode assembly which forms a dual capacitor with the gauge body. The two capacitances are used in post-processing to reduce the noise levels and to enhance the precision and accuracy of the measurements. The reference side is at high vacuum of the level 5 × 10-5 Pa. The vacuum of the reference side is generated using a Turbo Molecular Pump and is sustained by pinching-off the reference side at this vacuum. A getter pump is provided and energized for improving the vacuum which otherwise gets deteriorated due to outgassing in the reference region of the gauge. The fabrication methods adopted for fabricating the gauge are novel. The diaphragm is fabricated from bulk material using the electrical discharge method (EDM). This helped in achieving a perfect diaphragm with linear deflection with pressure variation and attained a 100% success rate. Unlike the fabrication by welding of plate, this method is robust, economical, and helped in achieving similar properties across the gauges. The second innovation is in the fabrication of electrode assembly. Unlike commonly used electrodeposited electrodes; the presented technique used copper plates which sandwich the Alumina dielectric. The plates are bolted/brazed/welded across the ceramic disc with the help of pins which also help in the parallel connection of the dual capacitors are described later. This made this method of fabrication largely rejection free with the potential of repairs and testing with different plate configurations. This paper is presenting the design, production, and calibration of the gauge using these fabrication techniques for 1 × 103 Pa to 1 × 105 Pa.

A Dual Carbon Lithium-Ion Capacitor Using Recycled Polymer Separator Derived Carbon Cathode and Graphite Anode from Spent Lithium-Ion Battery

Lithium-ion capacitors (LICs) are hybrid capacitors that target pushing the energy limits of conventional supercapacitors by incorporating a lithium-ion battery (LIB)-type electrode without compromising much on the power density and cycle life of capacitors. Herein, a LIC is assembled using an ordered porous carbon cathode derived from the recycled polymer separator of spent LIBs and recycled graphite anode from the same source. The carbon-rich polymer is thermally stabilized and carbonized to utilize its porosity for ion storage and ordered matrix for better electronic conduction. The cathode half-cell delivers a capacitance of ∼100 F g−1 till 1000 cycles at 1 A g−1. In contrast, the anode half-cell delivers a capacity of 130 mAh g−1 under similar conditions. The assembled LIC provides an energy density of 129 Wh kg−1 at a power density of 275 W kg−1 and 54 Wh kg−1 at a high-power density of 13750 W kg−1. The LIC cycles with >70% capacitance retention till 6000 cycles. Further, the ion-storage mechanism of the LICs as well as their capacitive and diffusion-type contribution, is studied. The self-discharge and leakage current tests were performed in the cells to understand their practical feasibility.

All-Solid-State Ultrashort Pulse Generator by Capacitive Chopping Circuit

High-voltage ultrashort pulse (HVUSP) is attaching more attention to advanced biomedicine. In this paper, a capacitive chopping circuit (CCC) topology with all-solid-state switches is proposed, which can generate adjustable HVUSP with high power efficiency. Dual capacitors of opposite polarity are connected in series with the load, thus cutting off the discharge loop of a single capacitor and chopping out a narrow pulse with adjustable width. The CCC can be stacked modularly for higher amplitude. The working principle is analyzed and the power efficiency under different working conditions is simulated, along with existing modularized HVUSP generation topologies. Finally, an 8-staged all-solid-state prototype based on the proposed CCC topology is developed. The adjustability of pulse parameters and staged performance are tested. The pulse width can be compressed to less than 10ns at 6.5kV. Output parameters can satisfy HVUSP electroporation in the biological scene.

Linear Modulation Region Expansion Strategy Based on Voltage Vector Angle Regulation for PMSM Drives With Small DC-Link Capacitor

Modulation fluctuations will decrease the linear operation range and cause the reduction of DC-link utilization for reduced DC-link capacitance motor drives. In this paper, a novel strategy for expanding the linear modulation region based on voltage vector angle regulation is proposed. The phase relationship between the voltage reference and the DC-link voltage fluctuation is carried out creatively to clarify the reduction of linear modulation margin. Based on the impedance matching method, the linear modulation region can be expanded by reducing the phase differences with the regulation of voltage vector angle. According to parameter and performance analysis of the proposed method, the DC-link utilization can be improved by 13.2%. Experimental results validate that the effectiveness of the proposed method.

An Improved One-to-Three WPT System With Tunable Compensation Network and Enhanced Pulse Density Voltage Control

In order to realize selective power transfer and output voltage regulation of LCC-S compensated one-to-three wireless power transfer (WPT) system, a novel control strategy based on dual switch-controlled capacitor (DSCC) and enhanced pulse density voltage control (EPDVC) is proposed in this paper. The improved series compensation network increases the selectivity of the receivers. Then, by introducing the DSCC into the LCC topology, both the load-independent current in the transmitting coil and the zero voltage switching (ZVS) of the inverter are maintained under different operating frequency. Besides, the common phase shift modulation (PSM) used to regulate the output voltage is substituted by a novel pulse density control strategy to overcome the hard switching issue when the system operates at light load. To verify the theoretical analysis, a 200-W prototype with 50-V input voltage is built and tested. The experimental results validate the selectivity of the one-to-three WPT system and the feasibility and stability of the proposed control strategy based on dual SCC and EPDM. The inverter achieves ZVS within the whole output power range under different operating frequencies and the peak efficiency reaches 90.57% with resistive load.

Performance Analysis and Control of a Capacitor Start Induction Motor

Abstract: This paper presents an experimental study on the performance characteristics of a capacitor start induction motor. The objective of the study is to understand the starting torque, starting current, and speed control of the motor under different loads and input voltages. The experimental setup consists of a capacitor start induction motor, a tachometer, an ammeter, a voltmeter, a wattmeter, and a load. The motor is started by applying the input voltage to the stator winding, and the centrifugal switch disconnects the starting winding after the motor reaches a certain speed. The capacitor provides a phase shift in the current and voltage waveforms, which helps to start the motor. The motor performance is measured using the tachometer, ammeter, voltmeter, and wattmeter, and the data is analyzed to understand the efficiency and performance characteristics of the motor. The experimental results show that the motor can provide a high starting torque and efficient speed control with the use of a capacitor. The study provides practical insights into the performance characteristics and control of the capacitor start induction motor, and can be used to improve the energy efficiency of the motor in various applications.

Furfural residues derived nitrogen-sulfur co-doped sheet-like carbon: An excellent electrode for dual carbon lithium-ion capacitors

The state-of-the-art lithium-ion capacitors (LICs), consisting of high-capacity battery-type anode and high-rate capacitor-type cathode, can deliver high energy density and large power density when comparing with traditional supercapacitors and lithium-ion batteries, respectively. However, the ion kinetics mismatch between cathode and anode leads to unsatisfied cycling lifetime and anode degradation. Tremendous efforts have been devoted to solving the abovementioned issue. One promising strategy is altering high conductive hard carbon anode with excellent structural stability to match with activated carbon cathode, assembling dual-carbon LIC. In this contribution, one-pot in-situ expansion and heteroatom doping strategy was adopted to prepare sheet-like hard carbon, while activated carbon was obtained involving activation. Ammonium persulfate was used as expanding and doping agent simultaneously. While furfural residues (FR) were served as carbon precursor. The resulting hard carbon (FRNS-HC) and activated carbon (FRNS-AC) show excellent electrochemical performance as negative and positive electrodes in a lithium-ion battery (LIB). To be specific, 374.2 mAh g−1 and 123.1 mAh g−1 can be achieved at 0.1 A g−1 and 5 A g−1 when FRNS-HC was tested as anode. When combined with a highly porous carbon cathode (SBET = 2961 m2 g−1) synthesized from the same precursor, the LIC showed high specific energy of 147.67 Wh kg−1 at approximately 199.93 W kg−1, and outstanding cycling life with negligible capacitance fading over 1000 cycles. This study could lead the way for the development of heteroatom-doped porous carbon nanomaterials applied to Li-based energy storage applications.

Hierarchical porous activated carbon anode for dual carbon lithium-ion capacitors: Energy storage mechanisms and electrochemical performances

BackgroundUtilizing the graphite anode and activated carbon cathode to construct dual carbon lithium-ion capacitors (DC-LICs) is recently attracted much attention owing to their cost-effectiveness, enlarged operating voltage, high safety, etc. Despite these merits mentioned above, the kinetic mismatch and imbalance capacity among the electrodes restricts the rate capability and energy density, respectively. MethodsHerein, the high mass-loading (9 mg/cm2) and flexible electrodes composed of hydrogel-derived hierarchical porous activated carbon (HHPAC) are prepared by mechanically blending, repeatedly calendared, and completely dried at 130℃. The resulting free-standing sheets were adopted as electrodes for DC-LICs. Significant findingsBenefiting from the distinctive textural properties (e.g., graphitic layers, multi-porosity, and huge specific surface area of 2,012 m2/g), the energy storage mechanisms of HHPAC anodes simultaneously follow the intercalation and adsorption phenomena, which were confirmed by electrochemical and micro-Raman identifications. Moreover, an additional capacitive contribution (∼31%) and voltage delay of 64 mV are reflected at 5 mV/sec, as evidenced using cyclic voltammetry. Consequently, the DC-LICs assembled with pre-lithiated HHPAC anode and HHPAC cathode exhibited outstanding rate performances (39.7 mAh/g at 0.1 mA/cm2 and 20.3 mAh/g at 10 mA/cm2) and comparable cyclability (81% of retention after 1,400 cycles at 1 mA/cm2), revealing that our HHPAC materials are promising for serving as anode and cathode in DC-LICs.

Effect of varying carbon microstructures on the ion storage behavior of dual carbon lithium-ion capacitor

Dual carbon lithium-ion capacitors (LICs) are the next-generation hybrid energy storage devices that aim towards energy-power balanced applications. Thus, tuning the properties of the carbon electrode materials is a crucial step toward optimizing the device's performance. Herein, the effect of change in the microstructure of the carbon electrodes on the ion storage capacity and their consequent energy-power manifestation is investigated. The optimized carbonaceous anode calcined at 700 ⁰C delivers 290 mAh g−1 capacity after 1000 cycles at 1 A g−1. This superiority in performance is attributed to the formation of micron-size channels and mesopores for better ion transport and storage. In contrast, the activated carbon cathode delivers a capacitance of 118 F g−1 and retains 76% at the end of 5000 cycles. The LIC full cell with these electrode materials provides maximum energy of 120 Wh kg−1, a maximum power density of 20.7 kW kg−1 and cycles till 9000 cycles with ∼67% capacitance retention. The mechanistic control over the deliverable ion storage capacity is also analyzed for the LIC full cell. Furthermore, the lighting demonstration, self-discharge studies, leakage current, and electrochemical impedance are recorded to elucidate the practical feasibility and performance degradation mechanism of the coin-cell device.

Optimal Wireless Power Transfer Circuit without a Capacitor on the Secondary Side

This study proposes an approach to obtain maximum power via wireless power transfer using a single primary-side capacitor. It is shown that higher power is achieved when compared to the common wireless power transfer circuit under resonance with dual (primary- and secondary-side) capacitors. This approach is divided into three phases. By choosing the capacitor and frequency as freely assignable variables, we symbolically obtain a formula that allows us to determine the optimized capacitance and frequency for maximum power. To verify our method, we used a numerical analysis and compared it with an electronic circuit simulation. The symbolic formula is able to maintain maximum power despite changes in load or in the coupling coefficients.

Fractional-Order-Based Low-Order Harmonic Current Suppression Method Considering Asymmetrical Capacitor Parameters

The problem of the second harmonic current (SHC) on the dc bus side of the single-phase inverter system has attracted widespread attention. The active power decoupling method based on dual capacitors can suppress SHC effectively. However, the asymmetrical capacitor parameters will deteriorate the SHC suppression performance and lead to the first-order harmonic current. To eliminate these low-order harmonic currents, this article proposes a SHC suppression method based on the fractional-order capacitor (FOC), where no power supply is employed and little loss is incurred. The capacitance and the order of the proposed FOC can, both, be adjusted. The principle and operating mode of the FOC are analyzed, and the control strategy of adjustment is given. The method can realize the SHC suppression with the advantages of a simple control strategy, hot-swappable, and high flexibility. Most importantly, the method can effectively suppress the first-order harmonic current caused by the asymmetrical parameters of the capacitors. Finally, an 800 W prototype based on the proposed method is built, and the simulation and experimental results both verify the effectiveness of the proposed method.

Low cost high performance self-starting sensorless single phase induction motor drive

<p><span lang="EN-US">The present paper is directed to achieve a low-cost high-performance self-starting single phase induction motor (SPIM) drive system. A phase shifted pulse width modulation (PWM) trains feeding the motor will replace the starting and running capacitors. Adaptive sliding mode control, enhance with model reference adaptive control (MRAC), is implemented to achieve high performance sensorless SPIM drive. The obtained results confirm the feasibility of the proposed system in starting and fast tracking the reference speed with nearly zero percentage overshoot and zero steady-state error. Moreover, the proposed SPIM drive system is robust to external load torque disturbances and insensitive to system parameter variations. Extensive simulations have been conducted to confirm the validity of the proposed system.</span></p>