Series Inductance Research Articles

Wave Active Low Pass Filter Employing Modern Active Block VDDIBA

This paper presents a second and third-order wave active low pass filter (WALPF) using modern active block Voltage Differencing Differential Input Buffered Amplifier (VDDIBA) with a lower supply voltage of 1V. The wave-active approach is chosen for the filter designing to get a higher order, lower sensitivity, modular and stable filter structure. The design procedure of WALPF involves the implementation of wave-active equivalent for series inductor and shunt capacitor. And it needs to realize the subtractor block physically, and the lossy subtractor integrator block using VDDIBA gives a flavor of differencing voltage property. So, the physical implementation of the subtractor block and the lossy subtractor integrator block goes very smoothly using this block. It is considered a possible reason for reducing active blocks and passive components. Theoretical justification of the proposed WALPF is achieved by using the wave-equivalent concept of the wave-active approach. This method of WAF design consists of only one resistor and capacitor, making the filter structure less complex easy to use with a cut-off frequency of 10MHz. Finally, the workability test is examined with the PSPICE simulation that results in the WALPF frequency response using 180 nm TSMC CMOS technology parameter for VDDIBA.

Condition Monitoring of DC-Link Electrolytic Capacitor in Back-to-Back Converters Based on Dissipation Factor

Condition-monitoring systems are used to determine the best timing for predictive maintenance of power electronics converters. These monitoring systems can significantly reduce the converter repair time and increase system availability. In this article, an investigation has been conducted on the possibility of using the dissipation factor as a lifetime indicator of electrolytic capacitors. A criterion is also proposed based on the dissipation factor to detect electrolytic capacitors’ end of useful life. A method has been presented for measuring the dc-link capacitor dissipation factor in a back-to-back converter. Using this technique, it is possible to estimate the switching component of the capacitor current by measuring the output currents of the converter without a need to measure the capacitor current directly. The proposed method is simulated, and the impact of various factors, such as switching frequency, capacitor series inductor, and the network filter on the accuracy of the dissipation factor measurement, is discussed. Experimental results are also provided to validate the acceptable accuracy of the proposed method.

Comparative study of 220 kV overhead transmission lines models subjected to lightning strike simulation by using electromagnetic and alternative transients program

Introduction. In high voltage networks intended for the transport of electrical energy, lightning can strike an electric line striking either a phase conductor, a pylon or a ground wire, causing significant overvoltage on the transmission lines classified as stresses the most dangerous for transformer stations and electro-energy systems in general. Modeling transmission lines becomes more complicated, if the frequency dependence of resistance and serial inductance due to the effect of lightning strike in the conductors and in the earth is considered. The difficulty increases the fact that the parameters of the line can be defined and calculated only in the frequency domain, while the simulation of transients is wanted to be in the time domain. Problem. Several models (J.R. Marti, Bergeron, nominal PI, Semlyen and Noda) exist for the modeling of transmission lines, the Electromagnetic Transients Program/Alternative Transient Program software (EMTP/ATPDraw) gives the possibility to choose between these models which is delicate due to the fact that we do not have experimental results to validate and justify the choice among the models available in the software. In this context, practical value: the overhead transport line OAT-El Hassi (220 kV) of the city of Sétif located in the north east of Algeria is used for the modeling of lightning strike by using the EMTP/ATPDraw software. Originality. A comparative study of the investigation of a lightning strike on an existing high voltage transmission line by different models of existing lines in the EMTP/ATPDraw software library of this software. Results. It was concluded that the choice of the model of the line is very important given the accuracy and quality of the curves of the voltage presented at the different calculation points.

Predictive-Pulse-Injection-Based Dual-Inverter Complementary Sensorless Drive for 12/10 DC Vernier Reluctance Machine

A dc-excited Vernier reluctance machine (DC-VRM) using a 12-slot/10-pole-pair design exhibits the advantages of small torque ripple and a robust structure, which has good potential to be applied as an aerospace integrated starter/generator. By eliminating vulnerable position sensors, system reliability can be further improved by sensorless startup. However, driven by the traditional three-phase inverter, the phase inductance of the 12/10 DC-VRM becomes constant due to its complementary characteristic, which means the saliency effect in DC-VRM is obliterated, and thereby a sensorless operation using self-inductance detection cannot be applied. To release the machine saliency effect and further improve sensorless drive performance, a dual-inverter sensorless drive structure is introduced to reconstruct the machine saliency by using separated dual three-phase inverters. The released series inductance model with mutual inductance coupling is established through a piecewise function, and an accurate position estimation method without finite-element analysis or complex measurements is introduced. Moreover, by further analyzing the linearity of series inductance, the full-cycle inductance high-linearity range is composed of dual-inverter complementary features, and thus position estimation accuracy can be guaranteed. Through this feature, a predictive-position-based pulse injection sensorless drive method is proposed to improve acceleration performance with detection time reduction. Based on the predictive position, the detection pulses are only injected into one inverter whose corresponding phases are located at the inductance high-linearity range, thus decreasing the detection time and improving acceleration performance.

An RLL Current Sharing Snubber for Multiple Parallel IGBTs in High Power Applications

A resistor–inductor–inductor <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">(RLL)</i> snubber is proposed for high-power power electronic devices that use insulated gate bipolar transistors (IGBTs) in parallel. The <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RLL</i> snubber provides current sharing for parallel IGBTs by utilizing series inductors to decrease the rate of current change in turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> and turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> transients. Compared with other methods, the proposed snubber incorporates only passive components without additional sensors or control circuits, which shows its advantages of simple structure, strong applicability, and easy implementation. In order to further expand its application scope, the topologies of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RLL</i> snubber for multiple IGBTs in parallel are designed and improved. Experimental results of 5 and 6 parallel IGBTs validate the feasibility and effectiveness of the proposed snubber.

Thermal Management Design of Transformers for Dual Active Bridge Power Converters

A methodology for the design of compact transformers operating at high frequency is presented in this article. A particular emphasis is paid to the thermal management of the magnetic core and of the winding components. For a 7 kW dual active bridge dc–dc converter, the objective is to reduce the core volume (<80 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> ), improve the power efficiency (>99%) and integrate the serial inductance (8.7 μH) as being the leakage inductance of the transformer. A parametric study shows that the heating in the copper winding is very sensitive to the anisotropic thermal conduction behavior of the wire. Due to this characteristic, a pot-core configuration is prone to a higher warming compared with the E-E core geometry, as the efficiency of the winding cooling is lower. In order to take part of the self-shielding ability of pot cores, we studied new configurations in which internal thermal drains are inserted into voids specially designed to shorten the distance between the external cooled walls and the hottest points of the winding. The heating of internal components of the transformer and resulting thermo-mechanical stress peak is reduced by 40% paving the way for robust transformers with a power density that could theoretically reach up to 200 kW/dm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> .

A Three-Coil Wireless Power Transfer System using Self-Resonant Open-Bifilar Coils

A common trend in the field of wireless power transfer consists in the use of more than two coils in order to extend the link distance in terms of efficiency, in which the 3-coil system is of great interest due to its high efficiency. In these circuits, usually, the preferred method of compensation is the series (capacitor and inductor in series), mainly due to its simplicity. Another promising topic is the use of coils tuned at their self-resonant frequency, mainly because it could avoid the use of external capacitors to achieve the resonant state in the involved circuits. However a multiple-coil self-resonant frequency with series compensation system was not yet presented in literature. In this paper, using open-bifilar coils, we present a self-resonant 3-coil wireless power transfer system that behaves as common series compensated circuit. Practical results confirm the validity of proposed solution, in a proof of concept methodology, that is, without any optimization strategy applied. For this sake, three different distances between transmitter and relay coil are adopted, while a 10 Ω resistor is used as load, allowing a maximum efficiency of 47% at a distance of 8 cm between relay and load coil (coils diameter are 15 cm).

A Trans-Inverse Magnetic Coupling Single-Phase AC-AC Converter

This paper introduces a new single-phase AC-AC converter based on an impedance source circuit. Like the existing single-phase impedance source AC-AC converters, it has the buck-boost ability and direct ac conversion. The input and output voltage possesses the same ground, and the phase angle is maintained and reversed smoothly. The presented converter utilizes a coupled transformer which allows the designer to exploit the transformer’s turns ratio as a variable to attain the desired output voltage. Additionally, the used transformer provides an option to obtain higher voltage gain by decreasing the turns ratio. Hence, smaller size of the coupled inductors is required for the higher voltage cases. To eliminate the switching voltage and current spikes on the power switches, a safe commutation strategy is used instead of utilizing snubber circuits. Furthermore, the input current is continuous and sinusoidal with low harmonics thanks to embedding the input inductor in series with the input source. Additionally, a dynamic voltage restorer is presented based on the proposed converter to compensate the voltage sag and swell faults. Simulation results are provided to evaluate the theoretical analysis. Finally, a laboratory prototype has been fabricated to demonstrate the validation of the presented converter.

A Passive but Local Active Memristor and Its Complex Dynamics

This paper proposes a globally passive but locally active memristor, which has three stable equilibrium points and two unstable equilibrium points, exhibiting two stable locally active regions and four unstable locally active regions. We find that when the memristor operates in a stable local active region, the memristor-based second-order circuit with a parallel capacitor or a series inductor can produce periodic oscillation. Moreover, the memristor-based third-order circuit with two energy storage elements, a capacitor and an inductor, can produce complex chaotic oscillation, forming the simplest chaotic circuit.

A Compact Ultra-Broadband RF Rectifier Using Dickson Charge Pump

In this letter, an ultra-broadband rectifier is proposed and tested to get more RF energy from ambient. The rectifier using the Dickson charge pump increases the bandwidth and improves the dc voltage of the output load. The upper branch uses an inductor in series to counteract the capacitance of the imaginary parts of the diode and at the same time acts as a booster circuit to increase the output voltage. A shunt open-circuit stub acts as part of the matching network, tuning the imaginary part of the input impedance of the high frequency to realize the impedance matching of the ultra-broadband rectifier. The manufactured rectifier is measured and the result shows a fractional bandwidth of 145.5% (0.6-3.8 GHz) with an RF-to-dc power conversion efficiency (PCE) exceeding 40% at 8 dBm input power. And the measured efficiency remains over 50% across the frequency range from 1.6 to 3.4 GHz (including GSM1800, GSM2100, and WiFi). In addition, the rectifier made a maximum conversion efficiency of 66.6%.

A Low Loss Orthogonal Decoupling Magnetic Integrated Structure for Dual Active Bridge Converter

The volume of magnetic components (transformer and inductor) in a dual active bridge (DAB) converter is a crucial factor determining its power density. This article proposes an orthogonal decoupling magnetic integrated structure (ODMIS) for DAB converter, which aims to reduce the volume of the transformer and inductor. The integrated series inductor and magnetizing inductor do not affect each other in the ODMIS, so the design process of the transformer and inductor can be separated. The condition to realize magnetic circuits decoupling of the transformer and inductor is derived. The loss characteristics of the magnetic core are analyzed, and the optimal decoupling condition to minimize the core loss is also derived. A 400 V/6 kW/20 kHz DAB converter prototype is built to validate the effectiveness of the ODMIS. The measured full-load overall efficiency of the DAB test platform is 97.55%, and the power density of the magnetic integrated components is 10.08 kW/L. Finally, the prototype comparisons between the proposed ODMIS and two existing magnetic integrated structures and discrete magnetic component method are conducted, and the advanced feature of the ODMIS is illustrated.

Reduction of Starting Current in Large Induction Motors

Large induction motors can have a high inrush and run-up current during starting, often up to ten times the rated current. In weak supplies, this could be a problem, causing system stability issues and the voltage to dip below acceptable levels. In islanded systems, the capacity could be pulled below its maximum. There are several different starting methods possible, but they are often only suitable for smaller machines. One method not investigated is the use of parallel capacitor compensation during the starting because large induction motors are very inductive during the starting sequence, so that supplying reactive power may be more effective than supplying energy. This paper first investigates several different induction motors with increasing size and assesses their compensation requirements in terms of the reactive power requirement during starting. It is shown that they do generally become more inductive as they increase in size. It is illustrated, using simulations, that using parallel capacitors during starting can significantly reduce the starting current. The concept is tested using a small experimental motor. Series inductors are added to the motor to make it more inductive and look more like a larger machine. The experimental results confirm that the method works. It is also found that the parallel capacitors require series filters to prevent harmonic current, and these can be realized using inductors in series with the compensation capacitors. Point-on switching using solid-state relays was tested, and these can reduce the transient switch-on current over the first voltage cycle.

The design of a high-voltage, long-pulse width, flat-top compensation pulse generator based on metal oxide varistors.

In recent years, the pulse forming technology based on metal oxide varistors (MOVs) has been verified to be an effective way to generate high-voltage quasi-square pulses. Due to the limited varistor voltage of a single MOV brick, multiple MOV bricks connected in series are required to stabilize a pulse with high amplitude (larger than hundreds of kV), which leads to the rise of the series inductance of the MOV branch and the flat-top droop in the output waveform. This paper provides two solutions to reduce the influence of the MOV branch inductance on output waveforms. One is that a coaxial evolute structure of the MOV bricks connected in series is designed, which can not only improve the insulation capacity but also reduce the branch inductance. Another is that a flat-top compensation scheme named "PFN-MOV" (Pulse Forming Network) is proposed, which adds an LC filtering branch to shape the signal into a flat-top rising wave with ripple and then offsets the flat-top droop caused by the inductance of the MOV branch. Based on the above ideas, a high-voltage, long-pulse width, flat-top compensation pulse generator is designed and tested, and a quasi-square pulse with voltage amplitude of more than 500kV, pulse width greater than 800ns, rise time of less than 50ns, and flat top of about 600ns is obtained experimentally. This MOV based generator has the advantage of simple design, compact construction, and better flat top, which is promising to be used as a compact long-pulse driver in many fields, such as high-current accelerator, industrial dedusting, medical sterilization, and cancer treatment.

Design of Continuous Class-B/J Power Amplifier Based on Mirrored Lowpass Filter Matching Structure

This paper proposes a methodology for designing broadband class B/J power amplifier based on a mirrored lowpass filter matching structure. According to this filter theory, the impedance of this design method is mainly related to the cutoff frequency. Series inductors and shunt capacitors filter out high frequencies. The change of input impedance with frequency is small in the passband. Which can suppress higher harmonics and expand bandwidth. In order to confirm the validity of the design method, a broadband high-efficiency power amplifier in the 1.3 - 3.9GHz band is designed and fabricated. Measurement results show that the output power is greater than 40.5dBm, drain efficiency is 61.2% - 70.8% and the gain is greater than 10dB.

Analysis of the Dual Side-Coupled RF Cavities for the HPM Devices—An Equivalent Circuit Approach

An equivalent circuit analysis was carried out for the dual side-coupled cavities (DSCCs) suitable as RF interaction structure in the high power microwave (HPM) devices and linear accelerators. Considering lossless structure, its equivalent shunt capacitance per unit length and series inductance per unit length are determined for the TM₀₁ mode operation. These equivalent circuit parameters were used to calculate the phase velocity and characteristic impedance of the DSCC. This was utilized further to appreciate the dispersion behavior of the DSCC. The developed analysis was also validated through electromagnetic simulations.

Passive and Online DC Bus Status Monitoring for Back-to-Back Converters Applied to Doubly Fed Induction Machines

This paper proposes a passive and a online estimator of the DC Bus parameters (series resistance Rs, inductance Ls, and capacitance C) used in Doubly-Fed Induction Machines (DFIM) for wind applications. These kind of machines are widely adopted as generators for wind applications, where predictive maintenance is an important cost-reduction driver. Two implementations are described, plug-in or parallel, depending on whether the algorithm runs in the application digital control platform (DCP) or as an standalone diagnostic device. Neither requires maintenance shutdown or DC current measurements to estimate bus parameters. In plug-in operation, the proposed method relies only on the electrical quantities required by the control system, i.e., stator-side and rotor-side voltages and currents. Conversely, in parallel mode, dedicated external voltage and current sensors are used. In both cases, the series RLC estimation is based on a recursive least squares (RLS) algorithm that works for the full speed range of regular operation required in wind energy applications. In this way, the replacement of deteriorated capacitors can be performed by monitoring the estimated parameters. The validity of the proposal is discussed based on a theoretical analysis, simulation results, and experimental validations.

A Quintupler Boost High Conversion Gain Soft-Switched Converter for DC Microgrid

This study proposes a high conversion gain soft-switching quintupler boost non-isolated converter for DC microgrid. By inclusion of quintupler rectifier and coupled inductor with reduced duty cycle, high voltage gain is obtained. The leakage energy of coupled inductor is recycled through an auxiliary switch and the output capacitor improves further boost. Due to the active clamp and this recycled leakage energy, huge inductive voltage spikes across MOSFETs are alleviated and also, stress is reduced. Hence, low voltage rating (low <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$R_{ds(ON)}$ </tex-math></inline-formula> ) switches can be utilized and minimize conduction losses. In addition, this clamp enables zero-voltage switching (ZVS) for both the MOSFETs, even at light loads. Quintupler multiplier rectifier reduces the voltage stress across diodes. This, in turn, reduces reverse recovery losses for multiplier diodes. Further, the coupled inductor leakage inductance in series with diodes provides for the snubbing effect to alleviate voltage spikes across quintupler diodes. Thus, the overall diode voltage rating reduces. This improves power density and improves the overall efficiency of the converter. Finally, a 400W prototype operates at 100kHz is developed to validate the converter performance. The measured peak efficiency is 96.43%.

Hybrid DC Circuit Breaker with Integrated Self-charging and Current Limiting

With the rapid development of DC power systems in recent years, more stringent requirements have been put forward for the fast reliability of DC circuit breakers. At present, in the medium voltage DC circuit breaker, the mechanical switch commonly uses an external secondary power supply to charge the mechanism drive capacitor, which has the problems of large breaker size and high cost. In this paper, we propose a DC circuit breaker topology that uses short-circuit current to charge the mechanism drive capacitor of the mechanical switch. When the short-circuit current rises, a voltage drop is formed across the series inductor, and this voltage charges the drive capacitor in parallel through a diode, avoiding the use of a secondary power supply to charge the drive capacitor and reducing the complexity of the DC circuit breaker system. The operating principle of the circuit breaker is analysed and the rationality of the proposed scheme is verified by simulation calculations.

Soft-Switched DC-DC Converter With T-Type Auxiliary Circuit for Vehicular Applications

This article proposed an isolated full-bridge dc&#x2013;dc converter (IFBDC) with T-type auxiliary circuit for vehicular applications. The proposed IFBDC operated with modified pulse width modulation (MPWM) ensured the zero voltage switching turn-<small>on</small> for the active switches of the converter during full-battery charging range. By using MPWM the value of the auxiliary and series inductance of the IFBDC is reduced as compared to phase-shift modulation operated converter. The proposed configuration also pursue the low-temperature rise during the battery charging process. The analysis of the converter is presented in ideal and nonideal parameters. Later, the analysis is verified on MATLAB/ Simulation and PSIM. To validate the results of simulation a 500-W, 80-kHz experimental prototype is developed and gating signals are given by using TMS320F28379D DSP controller.

A Broadband Antenna Based on a Single CRLH TL Unit Cell and a Parasitic Strip for Sub-1GHz DVB and LTE Applications

A Broadband and slim profile antenna based-on a single composite right/left-handed transmission line unit cell and parasitic shorted strip is presented for sub-1 GHz digital video broadcasting and long-term evolution applications (470-970 MHz). It is comprised of an ungrounded coplanar waveguide that feeds a meandered strip (distributed series inductors), which is connected through capacitive coupling (series capacitance) with a virtual small ground, while an upper shorted meandered strip represents a parallel inductor. A shorted meandered strip (parasitic inductor) is added to create a third resonant frequency. A broadband operation is achieved by merging three different resonant modes frequencies (zeroth-order mode and two quarter wavelength monopole modes) to satisfy 6 dB bandwidth criterion. A prototype is constructed and measured in order to verify the achieved results. The results of reflection parameter, gain, efficiency, patterns and bandwidth efficiency product are presented, discussed, and evaluated with respect to literature. The results show that the proposed antenna is a potential candidate for recent broadband digital video broadcasting applications.