Extra Inductor Research Articles

Detailed Review of a Novel Model SFCL for Grid

Our paper shows an RL-Indirect SFCL model (RL-I-SFCL). The applied superconducting tape is SF 12100 (Furukawa Electric Group). In the case of the operational current of a grid, the superconducting wire is in a serial connection with the grid as in a resistive SFCL. If we have a short circuit current on the grid, the RL-I-SFCL protection includes an extra inductance. This inductance is in a serial connection with the short circuit current. The change of the resistance of the superconducting wire creates an extra impedance in the main circuit without delay. It is an advantage. We have measured our SFCL and developed a simulation program by using MATLAB program. Hence, we could test our real measured results using a simulation program. We examined only the steady state in fault. Our checking was successful. We can protect the grid, switchgears and the superconducting wire effectively with this solution. We would like to contribute with this novel model solution to the development of an SFCL in industry because this technology is very simple and it can work safely.

A Hybridization of Cuk and Boost Converter Using Single Switch with Higher Voltage Gain Compatibility

In the current era, the desire for high boost DC-to-DC converter development has increased. Notably, there has been voltage gain improvement without adding extra power switches, and a large number of passive components have advanced. Magnetically coupled isolated converters are suggested for the higher voltage gain. These converters use large size inductors, and thus the non-isolated traditional boost, Cuk and Sepic converters are modified to increase their gain by adding an extra switch, inductors and capacitors. These converters increase circuit complexity and become bulky. In this paper, we present a hybrid high voltage gain non-isolated single switch converter for photovoltaic applications. The proposed converter connects the standard conventional Cuk and boost converter in parallel for providing continuous current mode operation with the help of a single power switch, which gives less voltage stress on controlled switch and diodes. The proposed hybrid topology uses a single switch with a lower component-count and provides a higher voltage gain than non-isolated traditional converters. The converter circuit mode of operation, operating performance, mathematical derivations and steady-state exploration and circuit parameters design procedures are deliberated in detail. The proposed hybrid converter circuit components, voltage gain and performance, were compared with other topologies in the literature. The MATLAB/Simulink simulation study and microcontroller-based experimental laboratory prototype of 150 W were implemented. The simulation study and experimentation results were confirmed to be a satisfactory agreement with the theoretical analysis. This topology produced non-inverting output in continuous input current mode using a single switch with high voltage gain (≈5.116 gain) with a maximum efficiency of 92.2% under full load.

Magnetic Functional Integrated DC Motor Drive

This paper presents the concept of magnetic functional integrated DC motor drive. It uses the field winding of a wound-field DC motor as the inductor of its drive circuit. The field winding in a wound-field DC motor not only builds the required magnetic field for the electric-mechanic energy conversion, but also acts as the inductor to buffer the energy for the drive circuit. One magnetic component is shared to realize different functions for motor and its drive circuit, simultaneously. The weight, loss and cost of the drive system can be reduced due to the saving of extra bulky inductors for the drive circuit. This concept can be applied to all DC-DC drive circuits using inductor as its energy buffer. An example of magnetic functional integrated DC motor drive using the buck-boost converter is used to explain the concept in detail. The feasibility and the new features are verified experimentally by comparing with the conventional motor drive.

Extended quasi‐Y‐source inverter with suppressed inrush and leakage effects

The Y-source inverter uses different turns ratios of a coupled inductor and a controllable duty ratio to vary its gain. However, its input current is discontinuous, and any leakage inductances of its coupled inductor will lead to unintentional dc-link voltage spikes and gain reduction. To solve these problems, an extended quasi-Y-source inverter has been proposed in this study, which compared with the Y-source inverter, uses an extra inductor and an extra capacitor. Although the extras may not appear attractive, they have successfully helped with the suppression of leakage effects, which decrease the voltage spikes, and hence permit the main magnetic core size to be much smaller. Concurrently, the continuous input current can be also achieved. Besides, inrush current at startup has been reduced to a more acceptable value, which together with other features of the proposed inverter, have been proven through experiments.

Initial Resonant Current Control for Extra-LC Auxiliary Resonant Snubber Soft-Switching Inverter Without Filter Inductor Current Sensor

The initial resonant current in the extra-LC auxiliary resonant snubber inverter (ELCARSI) is the key parameter to realize soft switching and improve output quality. However, the initial resonant current is related to the filter inductor current. Thus, an extra filter inductor or capacitor current sensor is required, which increases the cost and hardware complexity. Besides, the traditional control strategy using load current to calculate the initial resonant current doesn't require the extra sensor. However, the current stress and output distortion is increased. Thus, an initial resonant current control strategy without filter inductor current sensor is proposed in this paper. The operating principle of ELCARSI is introduced. The output quality and soft switching influenced by the initial resonant current are analyzed. Besides, the proposed sensorless control with estimation of filter inductor current is introduced. A prototype was developed to verify the effectiveness of the control method. The output distortion is close to that of the control with extra sensor.

Solar Fed High Step-Up Quasi Z-Source Converter For Induction Motor Drive Applications

Renewable energy sources (RESs) is the major source for the electrical energy in our future, the available systems are solar energy, wind, fuel cell etc. from these solar systems is commonly used as it is highly available. This source of energy is used for agricultural and industrial applications. Renewable energy source (RES) is feeding the motor in the agricultural fields, for motor to achieve high efficiency. Motor is designed for higher voltages, but to get higher efficiency in our solar system it must be designed for lower voltages. So, we need to boost lower voltage to higher voltage converter. Various high gain dc-dc converters are in the literature review and high gain quasi Z source converter uses switched capacitors and one extra inductor to get higher voltage gains. This paper mainly presents, integration of the PV system with high gain dc converter along dc ac inverter feeding to an induction motor drive. In order to extract maximum power incremental conductance algorithm is used in the photovoltaic panel. The converter is controlled by closed loop to maintain the output voltage to be constant. A Matlab Simulink models for high gain dc-dc converter drive applications are developed and outputs are obtained.

Miniaturised triple‐band antenna loaded with complementary concentric closed ring resonators with asymmetric coplanar waveguide‐fed based on epsilon negative transmission line

This study presents an open-ended triple-band miniaturised metamaterial (MTM) inspired antenna based on the epsilon negative-transmission line (ENG-TL). The zeroth-order resonance (ZOR) and first-order resonance (FOR) characteristics are implemented using the ENG-TL theory. The proposed MTM antenna consists of rectangular and square-shaped complementary concentric closed ring resonator (CCCRR) in the left and right half of the asymmetric coplanar waveguide (CPW) ground plane, respectively. The CCCRR generates an extra coupling capacitance and inductance, which help for improving the gain at ZOR mode and better impedance matching at higher-order mode. The resonance characteristic of the antenna is controlled by the shunt elements due to its open-ended boundary condition. The proposed triple-band MTM antenna offers measured -10 dB impedance bandwidths of 8.54% (1.12-1.22 GHz), 10.25% (2.22-2.46 GHz) and 35.75% (2.94-4.22 GHz). All these three bands show good impedance matching with appropriate gain and high radiation efficiency and also having an omnidirectional pattern in the xz- plane and dipolar type pattern in the yz -plane. The designed antenna shows an overall dimension of 0.11 λ 0 × 0.11 λ 0 × 0.006 λ 0 at ZOR frequency (1.16 GHz).

Module and System Considerations to Maximize Performance Advantages of SiC Power Devices

This paper extends a previously presented SiC power module design philosophy to critical, higher-level components for increased system performance, namely the DC bussing and DC link capacitor design. The DC bussing is essential to connect the DC bulk capacitors to the high-speed power modules and it is imperative that low inductance is maintained while current carrying capability and temperature be maintained. Often, high frequency capacitors are added to systems to increase performance by compensating for extra stray inductance that the DC bussing can introduce. However, issues that may arise by doing such are presented and it is shown that the best solution is to optimize the DC bus structure rather than compensate for a poor design. Finally, the implemented bussing is shown and full power system results presented for the inverter stack-up design.

Commutation Torque Ripple Suppression Strategy for Brushless DC Motors With a Novel Noninductive Boost Front End

This paper first presents a novel boost front end simply with a diode, a MOSFET, and a DC-link capacitor. Without extra inductors or other power components, the boost font end could boost the capacitor voltage with the motor stator inductances, thus reducing the influence of the limited DC-link voltage on commutation torque ripple reduction to a large extent. A unified commutation torque ripple suppression strategy is further proposed with the front end adopted based on the analysis about the effects of four switching vectors on motor speed regulation and DC-link capacitor voltage regulation. The proposed strategy can boost the DC-link capacitor voltage via properly selection of switching vectors under the premise of guaranteeing normal speed regulation in noncommutation period, and reduce both the commutation torque ripple and commutation time by two consistent switching vectors with the boosted DC-link capacitor voltage in commutation period. Finally, the proposed method is theoretically analyzed with respect to the capacitance selection and the boot capacity of noninductive boost front end. The correctness of the analysis and the effectiveness of the presented method are validated by the experimental results.

Miniaturized dual-band metamaterial inspired antenna with modified SRR loading

A miniaturized dual-band CPW-fed Metamaterial antenna with modified split ring resonator (SRR) loading has been presented in this paper. Proposed antenna comprises a tapered rectangular patch with a slot in which an elliptically SRR has been loaded to achieve miniaturization. Proposed antenna shows dual band operations in the operating band 3.25-3.42 and 3.83-6.63 GHz, respectively. It has been observed that lower mode (at 3.36 GHz) is originated by means of modified SRR. SRR is being modified by small meandered line inductor which is placed instead of strip. This provides an extra inductance to SRR resulting miniaturization. Overall electrical size of the proposed antenna is 0.222 × 0.277 × 0.017 λ0 at 3.36 GHz. Second band is due to coupling between feed and ground planes. The antenna offers an average peak gain of 1.72 and 3.41 dB throughout the first and second band respectively. In addition to that this antenna exhibits perfect omnidirectional and dipolar radiation patterns at xz- and yz- plane respectively. Due to consistent radiation pattern, ease of fabrication, and compact nature this antenna can be used for wireless applications such as worldwide interoperability for microwave access (WiMAX), industrial, scientific and medical (ISM) band, WLAN/Wi-Fi bands.

Design optimization of high frequency transformer with controlled leakage inductance for current fed dual active bridge converter

Current fed dual active bridge converters for photovoltaic generation may typically require a given leakage or extra inductance in order to provide proper control of the currents. Therefore, the many researches have been focused on the leakage inductance control of high frequency transformer to integrate an extra inductor. In this paper, an asymmetric winding arrangement to get the controlled leakage inductance for the high frequency transformer is proposed to improve the efficiency of the current fed dual active bridge converter. In order to accurate analysis, a coupled electromagnetic analysis model of transformer connected with high frequency switching circuit is used. A design optimization procedure for high efficiency is also presented using design analysis model, and it is verified by the experimental result.

Three‐phase qZ‐source inverter with fault tolerant capability

The requirement of three-phase inverters with high reliability capability is considered important in several applications. Most of the adopted fault-tolerant solutions use classical three-phase voltage source inverters (VSI) with redundant controlled power devices or modified control strategies for acceptably degraded performance in the event of a failure yielding the loss of devices. This work proposes the use of a fault-tolerant converter based on the quasi-Z-source inverter (qZSI). This inverter presents important features such as boost capability and not requires dead time circuits. These features associated to the proposed topology results in a converter with high reliability and fault-tolerant capability. The proposed topology is designed to allow the reconfiguration of the converter after a power switch failure, using only two legs in the faulty mode. Additionally, this topology avoids extra inductors, capacitors and active power switches for the fault-tolerant condition. A current controller associated to a vectorial voltage modulator is used to control the proposed topology, which results in three-phase balanced AC currents with reduced total harmonic distortion even in faulty condition. The performance of this solution is confirmed through experimental results obtained from a laboratory prototype.

A Magnetic Integrated LLCL Filter for Grid-Connected Voltage-Source Converters

High-order passive filters, such as the well-known LCL filters, are normally employed in the grid-connected power conversion systems to effectively attenuate the switching frequency harmonic introduced by the modulation of power converters. Although much more compact than the conventional single-inductor L filters, such passive filters are still bulky and expensive when compared with their active counterparts, e.g., the semiconductor switches. In order to improve the system power density and reduce its cost, the magnetic integration technique has been widely adopted so that the discrete inductors of passive filters are replaced by the integrated inductor, resulting in smaller magnetic cores and, therefore, the decreased volumes of passive filters. For conventional magnetic integrated LCL filters, the converter-side inductor and the grid-side inductor are integrated together and their coupling coefficient is intentionally minimized. In this letter, this coupling coefficient is fully utilized and properly designed, and the resulting coupling effect is equivalent to inserting an additional inductor into the filter capacitor branch loop. The integrated inductor and the filter capacitor can form an integrated LLCL filter, which exhibits the advantages of both the LLCL filter and magnetic integration, e.g., enhanced harmonic attenuation, reduced filter inductances, and system volume without adding the extra trap inductor. Finally, experimental results obtained from a single-phase grid-connected voltage-source converter interfaced by the proposed integrated filter are presented to validate its effectiveness.

Inductively Loaded Segmented Loop Antenna by Using Multiple Radiators

This letter presents a study of inductively loaded segmented loop antenna (SLA) by using multiple radiators. The identical radiators are stacked by multiple layers and excited in parallel. Through the study, it is found that the radiators can generate strong mutual inductive couplings, which induce extra mutual inductance in each unit cell. As a result, the physical dimensions of the antenna can be reduced to compensate the frequency shift caused by the couplings. In addition, by loading the radiators, the near-field radiation performance of the antenna is enhanced. It addresses the problem that smaller loop antenna often has lower field intensity. In this letter, single-layer (SL) (conventional), double-layer (DL), and triple-layer (TL) SLAs are demonstrated and compared theoretically and experimentally. The study shows that DL and TL antennas have 32 $\%$ and 58 $\%$ area reductions compared to the SL antenna, respectively. The proposed antenna can be a good candidate for the radio frequency identification system.

Resonant photodetector for cavity- and phase-locking of squeezed state generation.

Based on the requirement of squeezed state generation, we build the phase relationship between two electronic local oscillators for the cavity- and phase-locking branches, and a 2-way 90° power splitter is adopted to satisfy the phase relationship simultaneously, which greatly simplifies the experimental setup and adjusting process. A LC parallel resonant circuit, which is composed by the inherent capacitance of a photodiode and an extra inductor, is adopted in the resonant photodetector to improve the gain factor at the expected frequency. The gain of the resonant photodetector is about 30 dB higher than that of the broadband photodetector at the resonant frequency. The peak-to-peak value of the error signal for cavity-locking (phase-locking) with the resonant photodetector is 240 (260) times of that with the broadband photodetector, which can improve the locking performance on the premise of not affecting the squeezing degree.

Instantaneous current‐sharing control scheme of multi‐inverter modules in parallel based on virtual circulating impedance

Parallel multi-inverter modules are characterised by expandable output power and improved reliability. A current-sharing control scheme has to be employed to achieve equally load current sharing of paralleled inverters. At present, circulating active/reactive power are applied to control the voltage in some current-sharing control schemes; however, the size and weight are increased owing to the extra inductor. In this study, the concept of virtual circulating impedance is proposed and introduced into current-sharing control scheme to achieve ideal performance without increasing size and weight in multi-inverter modules in parallel. The mathematical model of circulating impedance is established and the relationship between the phase and the amplitude of circulating current, the phase of inverter module's output reference voltage is decoupled. Simulation and experimental inverter modules are built and operated in parallel system. The results of simulation and experiment verify that the current-sharing control scheme based on circulating impedance is available and efficient.

A 2.4-GHz highly linear derivative superposition Gilbert cell mixer

This paper presents a new derivative superposition Gilbert cell to minimize the third-order nonlinear current term of transconductance transistors. To decrease the parasitic capacitance effect on gain, noise figure, and linearity of the circuit, extra inductors and capacitors are added between the switching and transconductance stages. The proposed mixer is simulated in 0.18-$\mu $m RF-CMOS technology with a 1.8-V supply. The results show an improvement of about 23 dBm in IIP3 compared to conventional mixers. The power consumption of this circuit is about 3.96 mW.

Design of Bidirectional DC–DC Resonant Converter for Vehicle-to-Grid (V2G) Applications

In this paper, a detailed design procedure is presented for a bidirectional CLLLC-type resonant converter for a battery charging application. This converter is similar to an LLC-type resonant converter with an extra inductor and capacitor in the secondary side. Soft-switching can be ensured in all switches without additional snubber or clamp circuitry. Because of soft-switching in all switches, very high-frequency operation is possible; thus, the size of the magnetics and the filter capacitors can be made small. To reduce the size and cost of the converter, a CLLC-type resonant network is derived from the original CLLLC-type resonant network. First, in this paper, an equivalent model for the bidirectional converter is derived for the steady-state analysis. Then, the design methodology is presented for the CLLLC-type resonant converter. Design of this converter includes determining the transformer turns ratio, design of the magnetizing inductance based on ZVS condition, design of the resonant inductances and capacitances. Then, the CLLC-type resonant network is derived from the CLLLC-type resonant network. To validate the design procedure, a 3.5-kW converter was designed following the guidelines in the proposed methodology. A prototype was built and tested in the laboratory. Experimental results verified the design procedure presented.

Decoupling of Fluctuating Power in Single-Phase Systems Through a Symmetrical Half-Bridge Circuit

Single-phase ac/dc or dc/ac systems are inherently subject to the harmonic disturbance that is caused by the well-known double-line frequency ripple power. This issue can be eased through the installation of bulky electrolytic capacitors in the dc link. Unfortunately, such passive filtering approach may inevitably lead to low power density and limited system lifetime. An alternative approach is to use active power decoupling so that the ripple power can be diverted into other energy storage devices to gain an improved system performance. Nevertheless, all existing active methods have to introduce extra energy storage elements, either inductors or film capacitors in the system to store the ripple power, and this again leads to increased component costs. In view of this, this paper presents a symmetrical half-bridge circuit which utilizes the dc-link capacitors to absorb the ripple power, and the only additional components are a pair of switches and a small filtering inductor. A design example is presented and the proposed circuit concept is also verified with simulation and experimental results. It shows that at least ten times capacitance reduction can be achieved with the proposed active power decoupling method, and both the input current and output voltage of the converter can be well regulated even when very small dc-link capacitors are employed.

Equivalent circuit analysis of ‘U’-shaped split ring resonators

An equivalent circuit model of ‘U’-shaped split-ring resonators (SRR), the basic structure of SRR has been proposed and studied. The proposed model, other than traditional equivalent circuit model, has taken both the influence of geometrical parameters and dielectric substrate into account and investigated them in detail. Furthermore, the calculation formula of extra mutual inductance induced by periodic cells has been derived. The performance of the ‘U’-shaped SRR analyzed by the equivalent circuit model shows a good agreement with experimental measurements and numerical simulation in terahertz region. This work presents a novel method to predict the resonance frequency of complicated SPP accurately and paves an avenue for the future terahertz devices applications.