Circuit Losses Research Articles

An Efficient Resonant Pole Inverter Without Constant Circulating Current Loss in the Auxiliary Circuit

An Efficient Resonant Pole Inverter Without Constant Circulating Current Loss in the Auxiliary Circuit

Simulation Study on a Planar Quasi-Optical Waveguide Circuit for a W-Band Gyro-TWT With Stability Improvement

In this article, a planar quasi-optical waveguide (PQOW) circuit is proposed for vacuum electron devices (VEDs) for the first time. The circuit is made of a series of metamaterial pillars attached to a pair of parallel plates for phase compensation. It can propagate quasi-optical modes as a pair of concave mirrors does, while the lower order HE <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\text{0}\textit{n}}$</tex-math> </inline-formula> modes experience much heavier circuit loss compared to that of convention confocal waveguide circuits, which can improve the backward oscillation (BWO) stability of gyro-amplifiers. As an example, a W-band gyro-amplifier with PQOW circuits to replace conventional confocal circuits is designed. The 3-D particle-in-cell simulation demonstrated that the circuit is capable of producing stable high-power radiation within 96–108 GHz, with an electron efficiency of about 15% over the entire bandwidth.

In Vitro Model for Analysis of High-Flow Aerosol Delivery During Continuous Nebulization.

To understand the fate of aerosols delivered by high-flow nasal cannula using continuous nebulization, an open-source anatomical model was developed and validated with a modified real-time gamma ratemeter technique. Mass balance defined circuit losses. Responsiveness to infusion rate and device technology were tested. A nasal airway cast derived from a computed tomography scan was converted to a 3-dimensional-printed head and face structure connected to a piston ventilator (breathing frequency 30 breaths/min, tidal volume 750 mL, duty cycle 0.50). For mass balance experiments, saline mixed with Technetium-99m was infused for 1 h. Aerosol delivery was measured using a gamma ratemeter oriented to an inhaled mass filter at the hypopharynx of the model. Background and dead-space effects were minimized. All components were imaged by scintigraphy. Continuous nebulization was tested at infusion rates of 10-40 mL/h with gas flow of 60 L/min using a breath-enhanced jet nebulizer (BEJN), and a vibrating mesh nebulizer. Drug delivery rates were defined by the slope of ratemeter counts/min (CPM/min) versus time (min). The major source of aerosol loss was at the nasal interface (∼25%). Significant differences in deposition on circuit components were seen between nebulizers. The nebulizer residual was higher for BEJN (P = .006), and circuit losses, including the humidifier, were higher for vibrating mesh nebulizer (P = .006). There were no differences in delivery to the filter and head model. For 60 L/min gas flow, as infusion pump flow was increased, the rate of aerosol delivery (CPM/min) increased, for BEJN from 338 to 8,111; for vibrating mesh nebulizer, maximum delivery was 2,828. The model defined sites of aerosol losses during continuous nebulization and provided a realistic in vitro system for testing aerosol delivery during continuous nebulization. Real-time analysis can quantify effects of multiple changes in variables (nebulizer technology, infusion rate, gas flow, and ventilation) during a given experiment.

Regional Citrate Anticoagulation in Continuous Renal Replacement Therapy: Is Metabolic Fear the Enemy of Logic? A Systematic Review and Meta-Analysis of Randomised Controlled Trials.

Anticoagulation is recommended to maintain the patency of the circuit in continuous renal replacement therapy (CRRT). However, anticoagulation-associated complications can occur. We performed a systematic review and meta-analysis to compare the efficacy and safety of citrate anticoagulation to heparin anticoagulation in critically ill patients treated with CRRT. Randomised controlled trials (RCTs) evaluating the safety and efficacy of citrate anticoagulation and heparin in CRRT were included. Articles not describing the incidence of metabolic and/or electrolyte disturbances induced by the anticoagulation strategy were excluded. The PubMed, Embase, and MEDLINE electronic databases were searched. The last search was performed on 18 February 2022. Twelve articles comprising 1592 patients met the inclusion criteria. There was no significant difference between the groups in the development of metabolic alkalosis (RR = 1.46; (95% CI (0.52-4.11); p = 0.470)) or metabolic acidosis (RR = 1.71, (95% CI (0.99-2.93); p = 0.054)). Patients in the citrate group developed hypocalcaemia more frequently (RR = 3.81; 95% CI (1.67-8.66); p = 0.001). Bleeding complications in patients randomised to the citrate group were significantly lower than those in the heparin group (RR 0.32 (95% CI (0.22-0.47); p < 0.0001)). Citrate showed a significantly longer filter lifespan of 14.52 h (95% CI (7.22-21.83); p < 0.0001), compared to heparin. There was no significant difference between the groups for 28-day mortality (RR = 1.08 (95% CI (0.89-1.31); p = 0.424) or 90-day mortality (RR 0.9 (95% CI (0.8-1.02); p = 0.110). regional citrate anticoagulation is a safe anticoagulant for critically ill patients who require CRRT, as no significant differences were found in metabolic complications between the groups. Additionally, citrate has a lower risk of bleeding and circuit loss than heparin.

Refinement of the Steinmetz Coefficient for the Transformer Core Steel

The Steinmetz coefficient is the exponent of the power to which the magnetic induction amplitude enters in the expression for hysteresis loss in a ferromagnetic material. In various sources, the value of this coefficient varies from 1 to 3. Information on the exact value of this coefficient will make it possible to predict hysteresis loss more accurately, which in turn makes it possible to efficiently design transformers with low magnetic loss (no-load loss). Assuming that hysteresis loss is proportional to frequency and that eddy current loss is proportional to frequency squared and induction squared, an expression which determines the Steinmetz coefficient for a specific magnetic core is derived. The expression includes the total loss values measured in two no-load experiments, one of which was carried out at an increased magnetization frequency and the other at a reduced voltage. For a single-phase 1600 W transformer, the Steinmetz factor was estimated to be 1.62. A formula for determining the exponent of the power to which the magnetization frequency enters in the expression for the total loss in the magnetic circuit. For the transformer under study, this exponent has been found to be 1.42.

A comprehensive evaluation of hemodynamic energy production and circuit loss using four different ECMO arterial cannulae.

Pulsatile-flow veno-arterial extracorporeal membrane oxygenation (V-A ECMO) has shown encouraging results for microcirculation resuscitation and left ventricle unloading in patients with refractory cardiogenic shock. We aimed to comprehensively assess different V-A ECMO parameters and their contribution to hemodynamic energy production and transfer through the device circuit. We used the i-cor® ECMO circuit, which composed of Deltastream DP3 diagonal pump and i-cor® console (Xenios AG), the Hilite 7000 membrane oxygenator (Xenios AG), venous and arterial tubing and a 1 L soft venous pseudo-patient reservoir. Four different arterial cannulae (Biomedicus 15 and 17 Fr, Maquet 15 and 17 Fr) were used. For each cannula, 192 different pulsatile modes were investigated by adjusting flow rate, systole/diastole ratio, pulsatile amplitudes and frequency, yielding 784 unique conditions. A dSpace data acquisition system was used to collect flow and pressure data. Increasing flow rates and pulsatile amplitudes were associated with significantly higher hemodynamic energy production (both p < 0.001), while no significant associations were seen while adjusting systole-to-diastole ratio (p = 0.73) or pulsing frequency (p = 0.99). Arterial cannula represents the highest resistance to hemodynamic energy transfer with 32%-59% of total hemodynamic energy generated being lost within, depending on pulsatile flow settings used. Herein, we presented the first study to compare hemodynamic energy production with all pulsatile ECLS pump settings and their combinations and widely used yet previously unexamined four different arterial ECMO cannula. Only increased flow rate and amplitude increase hemodynamic energy production as single factors, whilst other factors are relevant when combined.

Research on Energy-saving Calculation of Navigational Lighting System Powered by Low Current in Green Airport

The airport navigation lighting system is an important energy-consuming system in the flight area. The annual energy consumption of large and medium-sized airports can reach millions of kilowatt hours. At present, the airport is replacing traditional halogen lamps with LED navigation lighting for energy conservation. For LED lighting under the traditional 6.6 A power supply system, the circuit loss is high, and the overall energy-saving effect of the system is not good. A low-current power supply energy-saving navigation lighting system is proposed. The primary cable, secondary cable, isolation transformer, and auxiliary lighting system in the navigation lighting circuit are studied by performing the energy-saving calculation of navigation lights under low currents. By building a set of navigation lighting systems to conduct energy consumption experiments and comparing them with theoretical calculations, a calculation model is proposed to provide a basis for energy-saving calculations for the application of a low-current power supply navigation lighting system.

実験値とデータシート値と近似式から構築した電力変換器の損失モデルの実機検証

This paper proposes a losses-analysis model of a DC-output converter based on the approximated equations from measurements and a datasheet. Target verification circuit consists of a DC-voltage source, a smooth capacitor, two half bridge legs, and a load inductor connected to the midpoints of the half bridge legs, which controls the continuous average DC current of the load inductor. A use of self-measured data, compared with the use of datasheet values, enables expanding the ranges of the considerable target parameters. Hence, lesser order approximated equations can deal with more target parameters with less calculation period than that in a conventional time domain simulation. In this study, calculation flow of losses from losses of power devices and an inductor to circuit losses was developed. Subsequently, a semiconductor losses model and inductor losses model were developed via the linear least square method. Finally, a 400V experimental system was developed to verify the accuracy of the circuit losses at 16 specified operating conditions by varying three verification parameters, switching frequency, gate resistance, and inductance. The result shows that the losses calculated using the proposed model has good accuracy with an error of 1.9% to 10.6% to the measured result.

Analysis of Exchange Power in the Power System of an Unmanned Aerial Vehicle with a BlDC Engine

The purpose of this work is the analysis of the power supply system of unmanned aerial vehicle. One of the most important tasks of this system is to ensure the smallest possible losses in order to achieve greater endurance of the aircraft, which means – the ability to complete the mission. The presence of an inactive component of consumed power obviously reduces the efficiency of the entire unmanned aerial vehicle. Considering also that due to the influence of wind, speed changes and other factors, the power system spends a significant amount of time in the transition mode, the impact of this phenomenon becomes even more significant. Thus, the phenomenon of the occurrence of exchange power in the power supply system of an unmanned aerial vehicle is analyzed. One of the most common solutions for unmanned aerial vehicles is the use of a BLDC motor, which is a further development of DC motors and was created with the aim of improving their basic characteristics. This type of engine has gained its popularity due to numerous advantages: high reliability, efficiency, speed and others. The principles of control of the BLDС engine are given. The unmanned aerial vehicle power supply system, built on the basis of a buck converter and a bridge inverter, was analyzed. An equivalent circuit of the converter is built, taking into account the losses in the electric circuit. On its basis the relations for determining the value of exchange power in the power supply system are derived. With the help of these expressions, it is possible to determine the value of the exchange energy at an arbitrary time interval in the real power supply system of the aircraft. A model of the power supply system of an unmanned aerial vehicle with a BLDC engine was built in the Matlab Simulink software environment. A time diagram is obtained, on the basis of which it is possible to draw a conclusion about the content of exchange power in the converter circuit. To minimize this phenomenon, it is necessary to develop a compensation system or an intelligent control system.

A Novel Single Phase Three Level Triple Boost CG Switched-Capacitor Based Grid-Connected Transformerless PV Inverter

A new three-level inverter based on the switched capacitor (SC) with a common grounding (CG) configuration has been introduced in this article, which is capable of boosting the input voltage up to three times. Therefore, this inverter is configured without any boost dc/dc converter stage for low voltage PV application. To step up the input PV voltage and facilitate three level in output voltage, two SC cells are connected in parallel. This inverter's common grounding configuration helps in bypassing the stray capacitance, which eliminates the leakage current and consequently reduces electro-magnetic interference (EMI) considerably. Hence, for electro-magnetic compatibility (EMC), this inverter does not require any EMI filter. Additionally, this inverter handles reactive power during the grid's lagging/leading power factor (pf) condition. A proportional resonant (PR) current controller is designed to regulate active and reactive grid power. The proposed modulation strategy helps in balancing capacitor voltages at their base values with allowable ripple. The inverter circuit details, control technique, PWM scheme, thermal modeling, and loss analysis with component design guidelines are described in detail. Experimental results are presented to validate the effectiveness and feasibility of this proposed inverter.

An Isolated SRC-Based Single Phase Single Stage Battery Charger for Electric Vehicles

In this article, a single-phase bridgeless electrolytic capacitor-less single-stage battery charger is proposed. The proposed charger consists of a bridgeless power factor corrector (PFC) circuit and an isolated series resonant converter (SRC). The series resonance circuit provides zero current switching (ZCS) for output diodes, thus reducing losses related to their reverse recovery. The resonant capacitors are designed so that the charger can operate in the range of 120–230-V input voltage, while ZCS is still guaranteed for output diodes. In addition, elimination of low-frequency input diodes decreases the circuit losses. The power factor correction and output power control are simultaneously achieved in one stage by using the proposed control method. The results obtained from a 350-W experimental prototype clearly confirm the correct operation of the proposed charger.

The Effect of Defect Charge and Parasitic Surface Conductance on Aluminum Nitride RF Filter Circuit Loss

When AlN thin films are deposited directly on the high-resistance silicon (HR-Si) substrate, a conductive layer will be formed on the HR-Si surface. This phenomenon is called the parasitic surface conduction (PSC) effect. The presence of the PSC effect will increase the power consumption of electronic components. Therefore, it is necessary to reduce the PSC effect. In prior technology, the polysilicon layer is usually used as the trap-rich layer to reduce the PSC effect. Experiments show that compared to AlN films deposited directly on HR-Si, the AlN substrates with polysilicon introduced on HR-Si have less radio frequency (RF) loss. To verify the effect of polysilicon on RF loss, polysilicon films of three different thicknesses and several different roughnesses were introduced. The results show that the thickness of the polysilicon will affect the RF loss, while the roughness has almost no effect on it. The polysilicon trap-rich layer can reduce the RF loss, which gradually becomes smaller as the polysilicon thickness increases.

Ultracompact terahertz plasmonic mode division multiplexer.

In this Letter, an ultracompact terahertz (THz) mode division multiplexer based on THz spoof surface plasmon polaritons (SPPs) is proposed. Compared with traditional optical multiplexing devices, the proposed mode multiplexer can be designed with a reduced footprint by exploiting more degrees of freedom in the parameters of the unit cell, namely a rectangular metallic pillar. The ultracompact mode division multiplexer can simultaneously support the propagation of four mode channels: the TM0, TM1, TM2, and TM3 modes. Then, we numerically evaluate the performance of a cascaded plasmonic mode division circuit composed of a mode multiplexer and demultiplexer. The cross talk and excess loss of the whole circuit are lower than -15 dB and 3.7 dB, respectively, for all four mode channels at a center frequency of 0.65 THz. The footprint of the whole device is about 27 × 2.3 mm and the length of each coupling region is about 2.7 mm. For the first time, to the best of our knowledge, a mode division multiplexer based on THz spoof SPPs is reported, which will form core devices for future THz on-chip multimode communication systems.

Low-cost fully additively manufactured passive microwave components exploiting available 3D flexibility

This paper presents a novel technique for low-cost realization of fully additively manufactured passive microwave components through Stereolithography and selective metallization. The introduction of the third dimension (Z-axis) allows to improve parameters of the circuits (impedance match, isolation, etc.) by realization of variable thickness air layers underneath the circuits’ patterns, which additionally lower the overall circuit losses caused by 3D printing material dielectric properties. Realization of a directional coupler, a low-pass filter, and a patch antenna utilizing the proposed manufacturing technique is discussed in detail and experimentally validated. The obtained measurement results for circuit demonstrators operating within the centimeter frequency range prove the benefits and performance of the introduced technique.

A 20 ns to 320 ns group delay controller and its application in long time delay self-interference cancellation system

A frequency tunable group delay controller (GDC) based on second-order reflective tunable resonant network and circulator is proposed. The GDC has continuous tunable group delay with allpass magnitude response. Trade-off between delay time and loss of general one-port lossy resonant circuit is studied, and a one-port second-order coupled-resonator structure is optimized. This proposed second-order reflective tunable resonant network is realized by microstrip resonators with optimized coupling location. A circulator is utilized to convert the reflection-type circuit to transmission type. The influence of the circulator isolation leakage upon the delay time is also analyzed. The GDC is designed, simulated and fabricated. Group delay can be tuned from 20 ns to 320 ns, and central frequency of the group delay response can be tuned from 940 MHz to 980 MHz. The insertion loss is less than 10 dB, 15 dB, 25 dB and 27 dB for 50 ns, 100 ns, 200 ns and 320 ns group delay, respectively. The figure-of-merit that the insertion loss per 1 ns delay of the GDC cell is the lowest among compared delay controllers. Two proposed GDC cells are then cascaded. The measurement demonstrates the bandwidth extension ability and the potential usage in full-duplex communication self-interference cancellation.

Novel Structure of Single-Shunt Rectifier Circuit with Impedance Matching at Output Filter

This study proposes a new structure of a single-shunt rectifier circuit that can reduce circuit loss and improve efficiency over the conventional structure. The proposed structure can provide impedance matching to the measurement system (or receiving antenna) without the use of conventional matching circuits, such as stubs and tapers. The proposed structure can simultaneously perform full-wave rectification and impedance matching by placing a feeding point on the output filter's λ/4 transmission line. We use circuit simulation to compare the RF-DC conversion efficiency and circuit loss of the conventional and proposed structures. The simulation results show that the proposed structure has lower circuit loss and higher RF-DC conversion efficiency than the conventional structure. We fabricate the proposed rectifier circuit using a GaAs Schottky barrier diode. The simulation and measurement results show that the single-shunt rectifier circuit's proposed structure is capable of rectification and impedance matching. The fabricated rectifier circuit's RF-DC conversion efficiency reaches a maximum of 91.0%. This RF-DC conversion efficiency is a world record for 920-MHz band rectifier circuits.

A nine‐level common ground multilevel inverter (9L‐CGMLI) with reduced components and boosting ability

SummaryThis paper introduces a common ground (CG) nine‐level switched‐capacitor (SC)‐based multilevel inverter (MLI) with dual boosting feature. The proposed circuit possess 11 switches, 2 diodes, and 3 capacitors. A simple level‐shifted modulation method has been used to generate the switching signals. The key feature of the proposed circuit is the presence of common ground between the input and output. The CG configuration eliminates the leakage current problem encountered in photovoltaic (PV) applications, which means the proposed circuit is suitable for use in PV applications. Moreover, the circuit also possesses reduced overall components and voltage stress on switches. At the same time, the dual boosting feature is another salient feature of the proposed MLI. This means the input voltage is stepped up two times and we get boosted/increased voltage at the output. The various simulation and experimental conditions have been tried to test the circuit under different load situations. Moreover, the loss analysis using PLECS software tool has been done to get information about the circuit losses. The results are shown and explained in the concerned sections of the paper. A quantitative comparison, based on different parameters, has been provided with other nine‐level MLIs.

Dynamic Voltage Equalization Control of D-STATCOM Under Unbalanced Grid Faults in a Low-Voltage Network

Unbalanced grid faults are very harmful to the network operation. Distributed static synchronous compensator (D-STATCOM) can help to support the grid voltage by injecting the reactive power into the inductive power grid. However, this approach turns to be ineffective for a low-voltage grid, where the network impedance is mainly resistive. In this article, a dynamic voltage equalization control (DVEC) scheme is proposed to suppress the negative sequence voltage, and therefore, reduce the voltage unbalance during the faults in the resistive network. This effect is achieved through transferring proper active power from the negative sequence channel to the positive sequence channel. And the dual-sequence active currents are controlled by DVEC without exchanging extra active power with the grid except the little circuit loss compensation. By flexibly adjusting the control parameter of DVEC, current peak and active power oscillation can be limited within a preset range, respectively, during the process of maximizing the voltage control. As a result, the DVEC scheme can ensure the safe operation of D-STATCOM and the stability of the power grid. Moreover, experimental results are reported to validate the correctness and effectiveness of the proposed scheme.

Internal Flow Field and Loss Analysis of a Magnetic Drive Pump’s Cooling Circuit

The cooling circuit is an important component of the magnetic drive pump because it prevents demagnetization of the permanent magnet and damage to the containment shell owing to a high temperature increase. In this paper, the flow field and losses of the cooling circuit of the magnetic pump are discussed and experimentally verified based on numerical simulation methods. Five different lengths of magnetic couplings were designed, and the flow field distribution, cooling flow rate, and loss variation laws of the cooling circuit were analyzed. The results show that the pump flow rate and magnetic coupling length have a minimal effect on the velocity distribution in the cooling circuit. When the magnet length increases from 30 mm to 55 mm, the temperature rise of the cooling circuit and the pressure drop at the gap increase by 23.1% and 25.3%, respectively. When the length of the magnetic coupling remains constant, the cooling flow rate of the cooling circuit falls with an increasing pump flow rate, and it reduces by 8.4% when the pump flow rate increases from 0.7 Q to 1.3 Q. The water friction loss and eddy current loss of the cooling circuit increase with an increase in the magnetic coupling length, while the cooling flow rate decreases. When the magnet length increases from 30 mm to 55 mm, the eddy current losses in the coupling circuit and the water friction losses in the cooling circuit increase by 45% and 35%, respectively, while the cooling flow rate decreases by 13%.

Statistical evaluation of the characteristics of damaged solar panels of spacecraft

The change in the characteristics of a solar battery as a result of a random abrupt change in the properties of individual solar cells, which occurred as a result of a single or systematic impact of adverse factors in near-Earth outer space, is considered. The choice of the calculation scheme for constructing a model of a single solar cell is substantiated. For this situation, analytical mathematical models of typical connections of solar cells have been developed. Using the developed models, the current-voltage and volt-watt characteristics of the solar battery are analyzed in the case of an abrupt decrease in the photocurrent of solar cells with different probabilities. A statistical analysis of the characteristics of damaged solar cells was carried out using simplified logical-analytical models with the introduced circuit loss coefficient. Estimates of the values of the coefficient of circuit losses for typical schemes for connecting solar cells are given. Keywords: solar cell, voltage characteristic, functioning model, damaged solar battery.