Circuit Power Loss Research Articles

Circulating and Eddy Current Losses in Coreless Axial Flux PM Machine Stators With PCB Windings

Printed circuit board (PCB) stators in coreless axial flux permanent magnet (AFPM) machines have been proposed, designed, and studied for use in multiple industries due to their design flexibility and reduction of manufacturing costs, volume, and weight compared to conventional stators. This paper investigates mechanisms and methods of approximating open circuit losses in PCB stators within example wave and spiral winding topologies for a dual rotor, single stator configuration using 3D FEA, analytical hybrid techniques and experiments. The effect of rotor magnet shape, end winding, and active conductor geometry on eddy currents is studied, and some mitigation techniques are proposed. Through stator equivalent circuit analysis, circulating current losses caused by mechanical abnormalities and magnetic circuit asymmetry are assessed. Possible strategies and schemes to minimize circulating current losses are also described. The trade-off between stator loss components and some practical design considerations are outlined in detail. The open circuit power losses of a prototype coreless AFPM motor were experimentally tested using multiple example PCB stators and emulated rotor asymmetries, with the findings being comparable to the FEA and hybrid analytical methods results.

Design strategy of IGCT clamp circuit parameters based on bi-objective nonlinear optimization

The integrated gate commutated thyristor (IGCT) is a high-power semiconductor device with excellent performance, whose operating characteristics are governed by the clamp circuit. In order to further optimize the operating characteristics of IGCT, a bi-objective nonlinear optimization strategy based on IGCT turn-off switching losses and clamp circuit transition time is proposed in this paper, by which the clamp circuit parameters can be obtained quickly and comprehensively. The results show that IGCT turn-off voltage drop and oscillation would be suppressed, and the IGCT turn-off and clamp circuit power losses could also be reduced, which ensures the safe operation of the IGCT and minimizes the impact on the dynamic performance of the power electronics converter based on IGCT in the meantime.

A General Approach to Programmable and Reconfigurable Emulation of Power Impedances

Starting with a brief review on the existing methods of impedance emulation, this paper addresses a general and systematic approach to programmable and reconfigurable emulation of power impedances. The proposed approach not only enables the impedance value to be programed, but also allows the characteristics (i.e., type) of the impedance to be reconfigured instantly during the operation. Based on the proposed control method, emulation of at least six types of emulated power impedances (EPI) can be easily attained. In particular, it is theoretically and practically demonstrated that the impedance characteristic can be emulated through a combination of different functions. The systematic derivation of these functions is explained. New techniques that compensate the circuit power losses are introduced. This general approach has been practically verified in several EPI. Both steady-state and dynamic performance of these EPI confirm the programmability and reconfigurability. It is envisaged that the proposed method can be applied to a range of functions, such as power filtering, energy storage, and even power conversion based on direct impedance control.

A novel method for optimal placement of vehicle-to-grid charging stations in distribution power system using a quantum binary lightning search algorithm

Vehicle-to-Grid (V2G) technology is currently used in plug-in hybrid electric vehicles (PHEV) during the discharging mode. This technology has become a considerable mechanism to provide a backup power source for distribution networks. In the meanwhile, these vehicles need Charging Stations (CSs) to receive power from the grid. Therefore, determining the optimal CS placement in the distribution network to utilize the V2G technology of PHEV has become an essential component so as to enhance the performance of the distribution network in the time of peak demand. This paper discusses a generalized methodology to assess the optimal placement when installing the CS in the distribution network. This optimization is done using a novel heuristic optimization technique called quantum binary lightning search algorithm. A multi-objective function is set to utilize the V2G technology to minimize line loading, voltage deviation, and circuit power loss. The performance of the proposed method is compared to the performance of other heuristic optimization techniques. As a result, the proposed algorithm has fewer limitations in terms of premature convergence than other heuristic optimization techniques.

Uneven temperature effect evaluation in high-power IGBT inverter legs and relative test platform design

This paper presents a high-power IGBT testing platform for uneven temperature conditions and its design criteria. Considering the influence of layout parasitic parameters on the measurement results, commutation rules and independent junction temperature control, a universal high-power switching characterization platform is built and operated. Importantly, it is capable of 3.6kA current level test requirement, which can cover the largest current level for the state-of-the-art IGBT modules. To improve the test accuracy of double pulse test method, a compensation algorithm is proposed to eliminate the circuit power loss under high current test conditions. Moreover, in order to simulate the uneven junction temperature effects occurring in real life, the junction temperatures of inspected IGBT and freewheeling diode are controlled independently. Quantitative analyses of the switching characteristics for junction temperatures up to 125°C are performed.

Multiphysics Model for Radio-Frequency Gridded Ion Thruster Performance

A multiphysics radio-frequency gridded-ion thruster performance model is presented. The model is composed of various submodels to account for different physics phenomena. A two-dimensional axisymmetric ion extraction submodel is used to estimate the ion optics effective transparency and beam divergence. A two-dimensional axisymmetric and three-dimensional molecular neutral gas submodels are used to calculate the ion optics Clausing factor and the discharge chamber pressure, respectively. An electron transport submodel determines the rate coefficients and the effective collision frequency by solving a two-term approximation Boltzmann equation. The plasma properties are calculated by employing a volume-averaged zero-dimensional plasma submodel. A fully three-dimensional thruster geometry is used for determining electromagnetic thruster and plasma parameters, such as the coupling coefficient, power losses, and field distributions. The submodel solves Maxwell’s equations in the thruster and plasma represented by a complex conductivity. To improve on the uniform plasma assumption, a radial variation in plasma density/conductivity is introduced. The impedance matching and circuit power losses are accounted for by a radio-frequency circuit submodel, in which the thruster is represented by a complex impedance obtained from the electromagnetic submodel. It is shown that the model predicts the Radio-Frequency Ion Thruster 3.5 experimentally measured radio-frequency generator power and current data values (and trends) within 13% error bound for various operational conditions.

Harmonic Impact of Plug-In Hybrid Electric Vehicle on Electric Distribution System

This paper presents the harmonic effects of plug-in hybrid electric vehicles (PHEV) on the IEEE 37-bus distribution system at different PHEV penetration levels considering a practical daily residential load shape. The PHEV is modeled as a current harmonic source by using the Open-Source Distribution System Simulator (OpenDSS) and DSSimpc software. Time series harmonic simulation was conducted to investigate the harmonic impact of PHEV on the system by using harmonic data obtained from a real electric vehicle. Harmonic effects on the system voltage profile and circuit power losses are also investigated by using OpenDSS and MATLAB software. Current/voltage total harmonic distortion (THD) produced from the large scale of PHEV is investigated. Test results show that the voltage and current THDs are increased up to 9.5% and 50%, respectively, due to high PHEV penetrations and these THD values are significantly larger than the limits prescribed by the IEEE standards.

Accurate Power Circuit Loss Estimation Method for Power Converters With Si-IGBT and SiC-Diode Hybrid Pair

An accurate power circuit loss estimation method has been developed for designing power converters with hybrid pairs of silicon (Si) insulated-gate bipolar transistor (Si-IGBT) and silicon carbide (SiC) Schottky barrier diode/SiC p-i-n diode. An analytical model of the switching losses of the hybrid pairs is proposed to achieve high accuracy and short calculation time. The nonlinearity of the device parameters and the stray inductance in the circuit are considered in the model. For the accurate power loss calculation, an empirical parameter extraction method is introduced for extracting device parameters. The calculated circuit power losses are compared with measurement results, and good agreements are confirmed. By using the proposed method, the power loss of a power converter utilizing 4.5-kV Si-IGBT/SiC-p-i-n-diode hybrid pairs is estimated to investigate the upper limitation of the switching frequency.

Theoretical Estimation of Peak Arc Power to Increase Energy Efficiency in Electric Arc Furnaces

This research work introduces the concept of “useful arc power” and the thermal model, first introduced by Dittmer and Krüger, to establish the arc length at any stage of the heat in Alternate Current Electric Arc Furnaces (AC-EAF), based on the estimation of the fraction of the energy transferred to the metallic load by radiation. Radiation is the most effective way to transfer heat in an arc furnace in presence of metallic scrap (bore-in and early meltdown). On the other hand, if the arc is not adequately covered with slag, radiation is extremely dangerous to the furnace integrity. When the furnace is fully loaded, scrap protects the walls and cooling panels and then arc radiation must be maximized. To increase energy efficiency, and at the same time reduce circuit power losses, the arc length should be controlled. However, arc instability prevents to increase radiation, as desired, and a compromise must be reached between arc length and arc stability. In this work AC-EAF electric circuit is modeled and analyzed under different heat stages. Electrodes, anode and cathode, fall regions can be considered as energy losses and their associated power may be deducted for the estimation of the “useful arc power” and for the definition of the operational currents in the heat process, particularly during flat bath conditions (late meltdown and refining). As a result of the present study it is proved that current setpoints play an important role for energy saving at any stage of the heat. Finally, experimental results obtained from an industrial steel factory validate this approach to optimize the electrical energy consumption per ton of liquid steel in AC-EAF.

Estimation of general energy-savings in three-phase ac power circuits by balancing phase currents using power active filter

Analyzing the ways of circuit power loss decreasing by balancing phase currents, the authors obtained analytical relations permitting to estimate power consumption decrease in a three-wire and four-wire ac circuit using a power active filter

Analytical loss model of power MOSFET

An accurate analytical model is proposed in this paper to calculate the power loss of a metal-oxide semiconductor field-effect transistor. The nonlinearity of the capacitors of the devices and the parasitic inductance in the circuit, such as the source inductor shared by the power stage and driver loop, the drain inductor, etc., are considered in the model. In addition, the ringing is always observed in the switching power supply, which is ignored in the traditional loss model. In this paper, the ringing loss is analyzed in a simple way with a clear physical meaning. Based on this model, the circuit power loss could be accurately predicted. Experimental results are provided to verify the model. The simulation results match the experimental results very well, even at 2-MHz switching frequency.

Investigation on the Minimum Maintenance Discharged Power of a Low-Frequency Driven Electrodeless Compact Fluorescent Lamp-Buffer Gas and Driving Frequency Dependence-

We have investigated the minimum discharged power to maintain lamp plasma in terms of dependence on buffer gas condition and driving frequency of the electrodeless compact fluorescent lamp (ECFL). It is essential for realization of the low-frequency driven ECFL with inductively coupled plasma technique for household use. Considering the point of cost, the driving frequency of the electrodeless discharge lamp should be lowered because high frequency driving (> 1MHz) requires special components for reduction of EMI noise and circuit power loss with the increase in driving frequency. But it is difficult to maintain plasma at low frequency driving, since induced electric fields, which excited with the induction coil is declined and not receive energy for ionization and discharge sufficiently. Here, we indicated that the condition of minimum power to maintain the H-mode (inductively coupled) discharge described as simple functions of buffer gas pressure and driving frequency for a fixed lamp bulb shape and found that the relation can represent the measured data well. Using that relation, we can easily predict optimum buffer gas pressure from driving frequency and required minimum maintenance power on the commercially available (practical) standpoint.

Ferroelectric capacitors for discharge lamp ballast circuits

Abstract Discharge-lamp ballast circuits of the type commonly used in the USA utilize an organic ballast capacitor. We have shown that substituting a ferroelectric ceramic capacitor with its dielectric nonlinearity improves the performance of the ballast circuit. Fluorescent and other discharge lamps operate more efficiently, and the ballast transformer circuit power losses are reduced. We will show that the ballast related characteristics of such nonlinear capacitors can be described by six parameters of an equation which represents the nonlinearities as well as hysteresis. A high-precision computer simulation was used to optimize the ballast-capacitor combination and find the shape of optimum nonlinearities. A tolerance study was also performed on the capacitor parameters. Extensive in-circuit testing of several different materials was used to define system and material requirements.