Additional Induction Research Articles

Note: Novel trigger pulse feed method for mega-volt gas switch.

It is difficult to feed the trigger pulse into an electrically triggered mega-volt switch, and the present note presents a novel trigger pulse feed method. The trigger pulse is introduced via a damping resistor, which is mounted between the inner and outer cylindrical electrodes of the pulse transmission line. The mega-volt pulse is damped because the voltage is resistively divided by the resistor and trigger cable arrangement. Both the complex breakdown processes of the switch and its insulation issues are experimentally studied. The function and the beneficial effects of the damping resistor, installed together with an additional inductor, are discussed. Finally, the parameters of these two damping components are set to 500 Ω and 2 μH values for which the switch has been demonstrated to work successfully at over 2.3 MV.

Design of a Novel Integrated L-C-T for PSFB ZVS Converters

To enhance the zero-voltage switching (ZVS) range and power density of the phase-shift full-bridge (PSFB) ZVS converters used in geophysical exploration, an additional resonant inductor is used as a leakage inductance and a blocking capacitor which is equivalent to interlayer capacitance is integrat...

A Bridged Contactless Measurement Technique for LC Tank Based Voltage-Controlled Oscillator

This paper presents a bridged contactless measurement technique that can measure the resonant frequency and quality factor of a fully-integrated powered off voltage-controlled oscillator (VCO). Unlike the use of the conventional two-coil inductive link, the proposed technique uses an additional inductor to bridge the coupling between the LC tank and the external inductor serving measurement purposes. This makes it possible to examine the on-chip high frequency oscillator with an off-chip inductor at Printed Circuit Board (PCB) level. As an example, a K-band VCO as well as the proposed test structure have been designed and simulated using 0.13 μm CMOS technology. The quality factor and operating frequency of the oscillator are measured using the proposed contactless technique through extraction from the frequency response of a bridged inductive link. The efficiency of the method has been validated by full wave electromagnetic simulation. As a reference, the characterization of the oscillator is also obtained using the Cadence Spectre RF and Mentor Graphic's Calibre PEX commercial Electronic Design Automation (EDA) software. The results of these two solutions agree considerably well, which supports the feasibility and potentials of using this technique for contactless measurements.

Implicit Common-Mode Resonance in <italic>LC</italic> Oscillators

The performance of a differential LC oscillator can be enhanced by resonating the common mode of the circuit at twice the oscillation frequency. When this technique is correctly employed, Q-degradation due to the triode operation of the differential pair is eliminated and flicker noise is nulled. Until recently, one or more tail inductors have been used to achieve this common-mode resonance. In this paper, we demonstrate that additional inductors are not strictly necessary by showing that common-mode resonance can be obtained using a single tank. We present an NMOS architecture that uses a single differential inductor and a CMOS design that uses a single transformer. Prototypes are presented that achieve figure-of-merits of 192 and 195 dBc/Hz, respectively.

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.

Analysis and design for interleaved ZCS buck DC-DC converter with low switching losses

This paper presents an interleaved buck DC-DC converter using zero current switching (ZCS) resonant with additional inductor and capacitor that mainly used for battery charging applications. The proposed novel converter has advantages of its simplicity, low cost, high efficiency and behaviour of easy control under the (ZCS) condition so that reducing the switching losses. Therefore, the proposed converter offers lower switching losses with a higher power density. The performance of the converter system is improved using coupled inductors. These coupled inductors reduce the magnetic size and also improve the converter's transient performance without increasing the steady-state current ripple. The detailed study of operating principle and design considerations is presented. The effectiveness of the proposed control scheme is demonstrated through PSIM simulations. Calculated efficiency of the converter is ensured about 94%, which is substantially considered to be a satisfactory performance.

A ZCS-PWM Voltage-Driven Three-Level Converter With a Secondary-Side Simple Soft-Switching Snubber

A very simple, low component count snubber is used in order to get ZCS for all the switches of a three-level voltage step-down converter. ZCS allows for the implementation of the switches with insulated-gate bipolar transistor which are able to withstand large input voltages at large power. The snubber is placed in the secondary-side, before the rectifier. The transformer leakage inductance is used in the ZCS-purposed resonant process, eliminating thus the need for an additional resonant inductor. All the resonant circuit energy is recuperated to the load. No voltage stresses appear on the switches, and the current stress is limited in a tradeoff components design. The proposed solution allows for a boost of the effective duty cycle. As a result, the proposed converter operates with a high efficiency.

Zero‐current‐switching bidirectional interleaved switched‐capacitor DC–DC converter: analysis, design and implementation

The study presents experimental verification of a zero-current-switching (ZCS) bidirectional interleaved switched-capacitor (BISC) DC-DC converter that features bidirectional power flow capability and a high-voltage conversion ratio. In addition, the interleaved configuration of the converter and its modular design enable both its current rating and voltage gain to be increased. At the same time, the converter does not exhibit current spike issues, which is achieved by employing stray inductance distributed throughout the circuit, rather than relying on an additional magnetic-core inductor. Moreover, the ZCS operation of the converter improves the converter efficiency. The operating principle and theoretical analysis of the BISC converter under both forward and reverse modes are presented in detail. Simulation and experimental results from a 1.5 kW prototype validate the operation and characteristics of the BISC DC-DC converter.

Energy Compression of Dielectric Barrier Discharge With Third Harmonic Circulating Current in Current-Fed Parallel-Series Resonant Converter

An advanced technique of energy compression with the third harmonic circulating current generation is presented in this paper to improve the surface treatment performance in the dielectric barrier discharge (DBD) systems. First, the relationship between the energy compression degree and contact angle is explored, which shows that the polymer surface wettability can be improved by the high energy compression degree in DBD. And then, an additional inductor is inserted into the resonant tank in the current-fed parallel-series resonant converter to generate the third harmonic current component, which can reduce the discharge-time-ratio and compress the energy transferred to the DBD loads. Furthermore, the method of rectifier-compensated fundamental plus third harmonic approximation (RCFTHA) is introduced to describe the current-fed parallel-series resonant converter by superposing two equivalent linear circuits operating at the fundamental and third harmonic frequencies, respectively. Consequently, the discharge-time-ratio optimization with the parallel-series resonant tank design is realized. Finally, the experimental results from a 350-W prototype substantiate the effectiveness of the energy compression with the third harmonic circulating current and the accuracy of RCFTHA.

Design of a parallel-LC-compensated on-board charger for universal inductive charging in electric vehicles

This paper proposes an on-board charger with a parallel-connected LC circuit which works in coordination with the previously-proposed universal charger to achieve “real” universal inductive charging. For accurately tracking the optimal frequency and achieving soft switching of the primary charger, an additional inductor is connected in series with the P-connected resonant tank to form an “LCL” topology. Based on the voltage gain of the proposed resonant topology, a step-down DC-DC converter is used to generate standard charging voltage and current to EV batteries. The detailed design method of the LCL circuit and DC-DC converter is provided. Theoretical analysis demonstrates that the proposed LCL-compensated secondary resonant circuit has a stable output voltage vs varied magnetic coupling and load. Compared with series-compensated LC circuits, the proposed topology has two main advantages: a smaller range of the varied optimal AC frequency vs magnetic couplings and a much lower voltage stress on the resonant capacitance. Experiments based on a prototype of inductive charging system prove that the proposed on-board charger has high DC-DC efficiency, a smaller range of AC frequency, and a universally-achieved stable output.

Application of generalized switching laws for increasing current pulse value

To obtain the current pulses applied to the active load, the circuit breaking effect has been used in the primary winding of the pulse transformer. When the direct current voltage source is disconnected, the current of primary winding is reduced to zero, so that a current pulse is formed in the secondary winding of the pulse transformer that is transmitted into the load. A circuit of the inductive pulse generator operating on the basis of generalized switching laws was developed so as to increase the amplitude of current pulses in the active load and the corresponding power. The circuit contains a pulse transformer, the secondary winding of the pulse transformer is connected to the load, and an additional inductor is connected parallel to the primary winding of the pulse transformer. When the direct current voltage source is disconnected, the current of primary winding passes through zero and decreases to a negative value, which leads to a significant increase in the current pulse in the load. In accordance with the generalized law of commutation, the relationships for the calculation of the current jump of pulse transformer primary winding and a jump in the load current have been obtained. Using the state-space technique, mathematical models of the circuits mentioned above with linear active load have been developed. Theoretical and experimental studies have shown a significant increase in the current pulse value and its capacity in the active linear load when the inductive pulse generator has been used. The values of currents in inductive coils detected experimentally were practically the same as the calculated values.

Soft-Switching Step-Up Converter with Small Output Current Ripple

A soft-switching step-up converter with small output current ripple is proposed in this paper. The proposed converter is based on a voltage-boosting converter, named KY converter which has features such as small output voltage ripple, fast transient response, non-pulsating output current and clamped switch voltage stresses to input voltage. In addition to the features of the KY converter, the proposed converter provides soft-switching of all power semiconductor devices and reduces switching losses by utilizing a small additional inductor. Power switches operate with zero-voltage-switching (ZVS) and a power diode operates with zero-current switching (ZCS). Therefore, the system efficiency is improved and electrical noises are reduced significantly. The operational principle and a steady-state analysis of the proposed converter are provided in detail. In order to verify the theoretical analysis, experimental results based on a 60W prototype at a constant switching frequency of 200 kHz are presented.

Using Magnetic Coupling to Improve the 1H/2H Double Tuned Circuit

We report in this paper an analysis of double-tuned 1H/2H circuits that are capacitively or inductively matched to 50Ω ports. In this analysis we use a novel new parameter called the circuit fill factor (CFF). It provides a means of characterizing the performance degradation associated with additional inductors in the circuit in addition to circuit losses. This parameter allows for quick and insightful analysis of multiple tuned circuits for efficiency. It is also shown that magnetically coupled double-tuned circuits are less prone to unwanted spurious resonances due to their general symmetry which eliminates multiple ground paths in the circuit.

A Component-Minimized Single-Phase Active Power Decoupling Circuit With Reduced Current Stress to Semiconductor Switches

This letter proposes a novel circuit topology which can realize the power decoupling function without adding additional active switches into the circuit. The dc-link capacitor of a full bridge rectifier is split into two identical parts and the midpoint is connected to one leg through a filter inductor. With such a configuration, this leg can control the current going into the two output capacitors connected in series for power decoupling, and the other leg can control the line current according to active and reactive power requirement. The proposed topology does not require additional passive component, e.g., inductors or film capacitors for ripple energy storage because this task can be accomplished by the dc-link capacitors, and therefore its implementation cost can be minimized. Another unique feature of the proposed topology is that the current stress of power semiconductors can be reduced as compared to other existing active power decoupling circuits. This feature becomes more obvious when the converter operates with capacitive load, e.g., for grid voltage support. The operational principle of the proposed circuit is discussed, and experimental results are presented to show the effectiveness of the proposed circuit concept.

Design of a Nonisolated Fuel Cell Boost Charger for Lithium Polymer Batteries With a Low Output Ripple

In the design of a fuel cell charger, it is important to find a suitable topology and to design the converter to guarantee the performance of both the fuel cell and the battery. Most of the chargers developed so far have used step-down converters. However, since a small fuel cell stack can only generate a low voltage, it is necessary to use a step-up converter to charge batteries. In this paper, a nonisolated boost charger topology with an additional output inductor for a proton exchange membrane fuel cell is presented to meet the strict ripple requirements for the battery charge, and its control method using a proportional-integral (PI) controller is detailed. The feasibility of the boost charger and its control method is then verified through the experimental results.

Passive Lossless Snubbers Using the Coupled Inductor Method for the Soft Switching Capability of Boost PFC Rectifiers

In order to minimize switching losses for high power applications, a boost PFC rectifier with a novel passive lossless snubber circuit is proposed. The proposed lossless snubber is composed of coupled inductors merged into a boost inductor. This method compared with conventional methods does not need additional inductor cores and it reduces extra costs to implement a soft switching circuit. Especially, the proposed circuit can reduce the reverse recovery current of output diode rectifiers due to the coupling effect of the inductor. During turn-on and turn-off operating modes, the proposed PFC converter operates under soft switching conditions with high power conversion efficiency. In addition, the performance improvement and analysis of the operating effects of the coupled inductors were also presented and verified with a 3.3 kW prototype rectifier.

An 83.4% Peak Efficiency Single-Inductor Multiple-Output Based Adaptive Gate Biasing DC-DC Converter for Thermoelectric Energy Harvesting

This paper presents a 100 mV input, 500 mV output single-inductor multiple-output (SIMO) based step-up dc-dc converter with adaptive gate biasing (AGB) technique implemented in 0.18 μm CMOS technology for thermoelectric energy harvesting. The proposed AGB technique and near-threshold voltage (near- VTH) energy redistribution control (ERC) ensure high conversion efficiency over a wide range of load currents. The proposed method automatically reduces conduction and switching losses of power MOSFETs without the need for auxiliary power converters or additional off-chip inductors. The AGB technique reduces conduction and switching losses under heavy-load and light-load conditions, respectively. The experimental results show that the efficiency of the proposed converter is enhanced by 25.5% and 18% at output load currents of 1500 μA and 50 μA, respectively. The proposed step-up dc-dc converter achieves the lowest output voltage and provides the highest conversion efficiency of 83.4% to date in standard CMOS process for thermoelectric energy harvesting.

전류전도모드에 따른 Interleaved ZCT DC-DC Converter의 스위칭 손실 분석

In the issues of interleaved topology which have been in limelight as high power converter, various soft-switching methods are studied to reduce switching losses in high power application. The interleaved ZCT converter has an additional filter inductor to reduce losses of diodes during reverse recovery process. However, additional current conduction modes are occurred by the inductor, we need to analyze switching losses with inductor values on each mode. In this paper, current conduction modes and boundary conditions of interleaved ZCT converter are analyzed. In the conclusion, the minimum of switching losses in converter operation modes is analyzed by calculating switching losses.

Modeling and performance improvement of folded coupled lines in miniaturized Quasi-lumped directional couplers

An efficient modeling method for folded coupled inductors for application in quasi-lumped directional couplers designed in both symmetric and asymmetric structures has been proposed. The presented model takes into account the deteriorative effects which occur when coupled inductors realized as electrically short coupled-lines matched to the high impedance standard are folded into, for example, meander or spiral pattern. The deteriorative influence of coupled-lines' folding on the performance of the resulting directional coupler has been modeled as additional lumped inductors and capacitors on the schematic diagram of a quasi-lumped directional coupler's subsection. Moreover, it has been shown that this deteriorative influence can be substantially minimized when values of lumped elements constituting the directional coupler are appropriately changed. The proposed design procedure has been experimentally verified by measurements of two 3-dB single-section directional couplers designed in symmetric and asymmetric structures as quasi-lumped couplers with folded coupled inductors. The measurement results show a good agreement with both circuit and electromagnetic analysis which proves the correctness and usefulness of the presented methods. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:1–9, 2015.

Resonance frequency ratio control with an additional inductor for a miniaturized resonant-type SIDM actuator

A smooth impact drive mechanism (SIDM) is one type of piezoelectric actuator that converts a saw-shaped piezoelectric displacement to linear (or rotational) motion. For sufficient displacement, a soft-type multilayered piezoelectric element is essential; however, such a piezoelectric element prevents efficient driving due to its low quality factor. To overcome this problem, we proposed a resonant-type SIDM using a hard-type single-layered piezoelectric element. In this resonant-type SIDM, the first and third longitudinal resonant sinusoidal vibration modes were combined to obtain a quasi-saw-shaped waveform. To realize such a saw-shaped waveform, precise adjustment of the resonance frequency ratio is essential. However, it is not easy to regulate the resonance frequency ratio by just the transducer design because of the fabrication error. As a solution for this issue, this study proposes to adjust the frequency ratio by inserting an electrical inductor in series with the piezoelectric transducer. With this method, the resonance frequency ratio was controlled, and the rotor velocity increased as expected.