Copper Loss Reduction Research Articles

Evaluation of AC Copper Loss Reduction Effect of Magnetic‐Coated Flat Wire

Evaluation of <scp>AC</scp> Copper Loss Reduction Effect of Magnetic‐Coated Flat Wire

Fault‐tolerant operation for five‐phase permanent magnet synchronous machine drives with five‐phase six‐leg inverter

AbstractFive‐phase permanent magnet synchronous machine (PMSM) can operate under open‐circuit faults with the appropriate current regulations. However, the traditional current regulations based on the five‐phase half‐bridge inverter have to satisfy the constraint of zero neutral point current, which limits the fault‐tolerant performance of the machine. Thus, this paper investigates the current regulation based on the five‐phase six‐leg (FPSL) inverter, which relieves the zero‐neutral point current limitation, and both current regulations considering the maximum torque (MT) and minimum copper loss (MC) are derived under different open‐circuit conditions. The cost of the system has increased, but with the new regulations, better fault‐tolerant operation capability of the machine can be obtained under all kinds of open‐circuit faults. Moreover, with the introduction of the neutral point current, the machine can work under triple‐phase open‐circuit faults. In conclusion, the proposed control scheme based on the FPSL inverter expands the fault‐tolerant operation capability of the five‐phase PMSM. The experiment results prove the effectiveness of the proposed current regulation on increasing average torque or reducing copper loss under fault‐tolerant operation.

Design and Optimisation of a 5 MW Permanent Magnet Vernier Motor for Podded Ship Propulsion

The evolution of electric propulsion systems in the maritime sector has been influenced significantly by technological advancements in power electronics and machine design. Traditionally, these systems have employed surface-mounted permanent magnet synchronous motors (PMSMs) in podded configurations. However, the advent of permanent magnet Vernier motors (PMVMs), which leverage magnetic gearing effects, presents a novel approach with promising potential. This study conducts a comparative analysis between PMVMs and conventional PMSMs at a power level of 5 MW for podded ship propulsion, with a particular focus on the impact of gear ratios (Gr). An objective function was developed that integrates motor dimension constraints and the power factor (PF), a critical yet frequently neglected parameter in existing research. The findings indicate that PMVMs with lower Gr have lower mass and cost compared to those with higher Gr and traditional PMSMs, at a PF level of 0.7, which is high for Vernier machines. Moreover, PMVMs with lower Gr achieve efficiencies exceeding 99%, outperforming both their higher Gr counterparts and conventional PMSMs. The superior performance of PMVMs is attributed to lower current density and reduced copper loss, which contribute to their enhanced thermal performance. These details are elaborated on further in the paper. Consequently, these findings suggest that PMVMs with lower Gr are particularly well suited for high-power maritime propulsion applications, offering advantages in terms of compactness, efficiency (EF), cost-effectiveness, and thermal performance.

Investigation of a Parallel Hybrid Excitation Machine With Auxiliary Winding for Loss Reduction in Flux-Weakening Operation

An axial-parallel hybrid excitation machine (APHEM) with an auxiliary winding is proposed and investigated for loss reduction in the flux-weakening operation. The permanent magnet (PM) flux and wound field flux of the APHEM are different and coupled under the armature action. Based on the axial-parallel structure, an auxiliary winding is introduced into the PM part to make better utilization of the distinct PM flux. Because of the coupling of the two fields, this auxiliary winding not only couples the PM flux but also affects the wound field flux. Two major conclusions can be derived from the theoretical analysis. Firstly, the auxiliary winding couples the PM flux and produces extra torque, benefiting a smaller field current. Secondly, the auxiliary winding can suppress the phase voltage because of the larger characteristic current of the PM part than the wound field part. This facilitates a smaller d-axis armature current. The reduced currents favor the reduction in copper loss and core loss. Compared with the original APHEM under the minimum-copper-loss control, the proposed method achieves a 34% reduction in the maximum loss and a 60% decline in the maximum torque ripple ratio. Finally, the measured results verify the analysis.

Single-Phase Short-Circuit Fault Tolerant Control for Five-Phase Permanent Magnet Machines With Copper Loss Reduction

Single-Phase Short-Circuit Fault Tolerant Control for Five-Phase Permanent Magnet Machines With Copper Loss Reduction

Penerapan Kawat Litz Pada Motor BLDC Untuk Peningkatan Gaya Dorong Per Daya

Copper loss can cause a decrease in performance in BLDC motors, so efforts will be made to reduce copper loss by using Litz wire. Additionally, there have been studies that simulate the performance of Litz wire, but they have not been directly applied, especially to propeller thrust. The objective of this research is to implement Litz wire in a BLDC motor and analyze its performance for an increase in propeller thrust per power. The BLDC motor is wound with single wire and Litz wire. The analysis conducted compares the resistance, copper loss, thrust force, and thrust-to-power ratio of the single wire and Litz wire with the same wire cross-sectional area. The BLDC motor is equipped with a propeller to measure the thrust force. The average resistance of the single wire is 0.43 Ohms, while the Litz wire is 0.38 Ohms. The copper loss of the Litz wire is 7% lower than a single wire. The Litz wire exhibits a 3% improvement in thrust force compared to the single wire in the testing. The thrust-to-power ratio of the Litz wire is also 3% better during the testing.

Improved Settling Mechanisms of an Industrial Copper Smelting Slag by CaO Modification

A significant source of copper losses from pyrometallurgical copper extraction is attributed to dissolved and entrained copper in discarded slag. Entrained copper can be recovered via pyrometallurgical slag cleaning in a settling furnace, where the slag viscosity and copper droplet size distribution (CDSD) are critical parameters. Reduced copper losses suggest improved raw material efficiency, and the slag becomes a more environmentally safe byproduct. In this study, iron silicate slags from a smelting furnace are industrially CaO modified in a fuming furnace to contain a CaO content between 8 and 18 wt.%. The viscosity of slags with and without CaO modifications is evaluated in the temperature range from 1423 to 1723 K. The influences of the CaO modifications on the CDSD, slag matrix copper content, and total copper content were determined. The results show that the slag viscosity decreases with increasing CaO concentrations in the slag. In addition, the copper content decreases in the slag phase, and the CDSD shifts to contain relatively larger droplets. The effect of CaO slag modification reveals a linear relationship between the overall copper recovery and viscosity, which increased from 63 to 88% when the viscosity in the respective batch was 0.51 and 0.25 Pa·s.Graphical

AC Copper Loss Reduction in Planar Inductors With Magnetic Building Blocks-Based Gapless Parallel Symmetrical Magnetoresistance Structure

Fringing and proximity effects are the main reasons for serious ac copper loss in high-frequency planar inductors. In this article, a novel air-gapless core structure based on magnetic building blocks with magnetoresistance parallel and symmetrically distributed relative to the windings is proposed, in which two magnetic building blocks parallel to the PCB windings are made of metal soft magnetic material with low relative permeability and three magnetic building blocks perpendicular to windings are made of ferrite with high relative permeability. Equivalent magnetic circuit models and theoretical analysis for the proposed core structure reveal that even if the interleaved winding structure fails in the inductor, a better distribution of magnetomotive force can be obtained by optimizing the distribution of magnetoresistance. Compared with the conventional inductors using stand airgaps, both the fringing and proximity effects can be weakened by the designed parallel symmetrical magnetoresistance core structure, which has been verified in three-dimensional finite element analysis (FEA)-based simulations. The FEA calculated results show that the proposed optimized core structure can achieve a 46% reduction in ac resistance, and this advantage will extend with increasing frequency over a certain frequency range. The experimental validation includes converter efficiency test and inductor loss test on a high-frequency critical conduction mode Boost converter has been carried out, the maximum efficiency improvement was 1.4% and the inductor loss reduction is also verified.

Current optimization-based control of dual three-phase PMSM for low-frequency temperature swing reduction

In this paper, a control scheme based on current optimization is proposed for dual three-phase permanent-magnet synchronous motor (DTP-PMSM) drive to reduce the low-frequency temperature swing. The reduction of temperature swing can be equivalent to reducing maximum instantaneous phase copper loss in this paper. First, a two-level optimization aiming at minimizing maximum instantaneous phase copper loss at each electrical angle is proposed. Then, the optimization is transformed to a single-level optimization by introducing the auxiliary variable for easy solving. Considering that single-objective optimization trades a great total copper loss for a small reduction of maximum phase copper loss, the optimization considering both instantaneous total copper loss and maximum phase copper loss is proposed, which has the same performance of temperature swing reduction but with lower total loss. In this way, the proposed control scheme can reduce maximum junction temperature by 11%. Both simulation and experimental results are presented to prove the effectiveness and superiority of the proposed control scheme for low-frequency temperature swing reduction.

A universal wireless charging platform with novel bulged‐structure transmitter design for multiple heterogeneous autonomous underwater vehicles (AUVs)

AbstractAutonomous underwater vehicles (AUVs) are important mobile equipment for ocean observation. Subsea docking stations are used to charge AUV batteries to increase their cruise duration. Here, a universal wireless charging platform with a novel transmitter is developed to address the issues of poor compatibility existing in conventional docking stations. In order to guarantee a sufficient charging area and reduce copper losses, the proposed transmitter is designed to have a bulged‐structure surrounding coil and a centre coil in coaxial. Moreover, the parameters of the transmitter that impact the magnetic flux density are analysed and optimized by non‐linear programming by Quadratic Lagrangian (NLPQL) algorithm to achieve a field with desirable intensity and uniformity. The characteristics of the circuits under single‐load and double‐load conditions have been tested in air and tank experiments. The results verify that the proposed platform achieves both the universality and misalignment tolerance requirements.

Fault-Tolerant Control of Doubly Salient Electromagnetic Generator Based on Capacitor Split-Phase Bridge Converter Under Loss of Excitation

Doubly salient electromagnetic machine (DSEM) has the advantages of simple construction, easy power generation control and convenient fault de-excitation, making it a promising application in the aviation field. Aviation power generation system puts forward higher requirements for the reliability of generators. Despite the various studies on the fault-tolerant control of DSEM, there are few studies on fault-tolerant control of excitation fault in aviation power generation system. Therefore, the main purpose of this paper is to achieve fault-tolerant power generation (FTPG) system for doubly salient electromagnetic generator (DSEG) on the event of excitation fault and improve the fault tolerance ability of the system, while can improve output power and reduce copper loss of DSEG under loss of excitation. This paper analyses the basic principle of normal power generation about DSEG, establishes its equivalent circuit after excitation loss, and dissects the control strategy for the FTPG with loss of excitation based on a bridge converter. Besides, this paper also proposes a fault-tolerant control system and its control strategy based on a capacitor split-phase bridge (CSPB) converter for DSEG, with higher generated power as well as lower copper loss. Based on the above hypothesis, experiments are performed on a power generation system for 12/8 pole DSEG to verify the feasibility of the proposed method.

An Improved Direct Predictive Torque Control for Torque Ripple and Copper Loss Reduction in SRM Drive

This paper introduces a direct predictive torque control (DPTC) method to minimize the torque ripple and copper loss of the switched reluctance motor (SRM). Generally, there is a problem with torque ripple during the SRM’s commutation. In this method, the commutation optimization is provided by a direct predictive torque control algorithm. Firstly, the reachable range of phase torques is predicted and the boundary of two continuous phases is modified. By dividing the torque range directly to determine the torque allocation set, the suppression of torque ripple becomes simple. Secondly, considering the optimization problem of copper loss during commutation, a cost function only related to the phase current is constructed. Further, the minimization of copper loss can be achieved by solving the cost function, and the work of setting weight parameters is not required. Finally, the proposed DPTC method is tested by simulation and experiment in a three-phase 12/8-pole SRM drive system and the results are compared with the existing predictive torque control methods. The results show that the proposed method has less torque ripple and copper loss, which effectively improves the torque control performance.

Hybrid Resonant Switched-Capacitor Converter for 48–3.4 V Direct Conversion

As the power required by modern data center processors increases, the power architecture must be adapted; for example, 48 V distribution voltage allows to reduce copper losses by a factor 16 with respect to the use of traditional 12 V power architecture. In order to generate the required processor core voltage, a two-stage approach is usually preferred, where the intermediate bus voltage is generated using an unregulated resonant dc–dc converter as, for instance, an <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> converter. Compared to <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLCs</i> , hybrid resonant switched-capacitor converters (ReSCCs) make it possible to achieve large voltage conversion ratios without the need of high turns ratio transformers. In this letter, a novel hybrid ReSCC that performs a 48–3.4 V direct conversion is presented. A prototype of the proposed converter has been implemented, capable of providing a continuous output power of 440 W with a maximum efficiency of 96.3% at 30 A load current.

A Novel Pyramid Winding for PCB Planar Inductors With Fewer Copper Layers and Lower AC Copper Loss

Relying on the advantages of small size, good controllability, and consistency, printed circuit board (PCB) inductors are being widely used. For PCB inductors, reducing copper loss is one of the key issues. Although some research works focus on fringing effect in PCB planar winding, there are few methods to reduce proximity loss for PCB inductor. Regarding the abovementioned issues, this letter first improves the Ferreira’s 1-D copper loss model to accommodate the core feature of PCB winding: variable number of turns per layer. With this model, pyramid theorem is proposed that putting the layer with fewer turns into positions farther away from the air gaps can lower the total winding loss. Based on the theorem, this letter proposes a novel PCB inductor-winding structure named pyramid winding, which has fewer (or equal) turns on layers farther from air gaps. Pyramid winding has less copper loss, fewer copper layers, smaller size, and lower cost. In the experiment, inductor prototypes with the same six turns and ferrite pot cores but different PCB winding arrangements are built for a 300-kHz 2700-W LLC converter. Tests on inductor resistance and converter efficiency are done, and the pyramid theorem and the effectiveness of pyramid winding are verified.

Design and Analysis of a Dual‐Direction Hybrid Excitation Generator

With the wide use of new energy vehicles, the research and development of high‐performance generators become more important. The claw pole machine is very suitable to be used as an automobile generator because of its unique characteristics. However, its development is limited by the disadvantage of abundant harmonic content, especially when used with fractional slot concentrated winding layout. A novel dual‐direction hybrid excitation generator (DDHEG) is proposed in this paper. It has dual 3‐phase winding layout to reduce spatial subharmonic magnet motive force (MMF). Also, it uses dual 3‐phase rectifier bridge circuit to reduce armature current, so as to reduce copper loss. It uses rotor sleeve to reduce the eddy current loss in the rotor and permanent magnets (PMs) caused by higher order harmonics. It has hybrid excitation from both directions to improve the efficiency and terminal voltage. The basic characteristics of DDHEG are analyzed by finite element analysis (FEA) method. The highlights of the proposed DDHEG are illustrated. The simulation results and experimental results reveal that the proposed DDHEG can effectively adjust the terminal voltage at different loads and reduce the harmonics and loss to a satisfied degree. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Model Predictive Direct Torque Control of Switched Reluctance Motors for Low-Speed Operation

In this paper, a finite-control-set model predictive direct torque control (FCS-MPDTC) method is proposed to reduce the torque ripple of a segmented switched reluctance motor (SSRM) at the low-speed stage. Firstly, the prediction dynamic model is established, and the phase torque can be predicted by detecting phase current and rotor position signals. Then, the principle of power converter and selection of voltage vectors are introduced and presented. Considering torque ripple reduction, flux tracking performance and copper losses reduction, the cost function with phase torque, the amplitude of flux linkage and phase current, is established to select optimal voltage vector to control the power converter. In addition, the torque sharing function (TSF) is employed to distribute total torque to phase torque for further torque ripple reduction. Finally, the direct torque control (DTC) is selected as the comparison method, performance of MPDTC is verified by simulation and experiment results. It can be found that the proposed MPDTC can achieve lower torque ripple and copper losses, and high robustness.

Disturbance Observer Based Sensorless Predictive Control for High Performance PMBLDCM Drive Considering Iron Loss

The control of motor drive without considering iron loss affects the phase back electromotive force and the torque performance. This article investigates the performance of permanent magnet brushless direct current motor (PMBLDCM) modeling taking impact of iron loss into account. A disturbance observer based sensorless scheme is proposed for PMBLDCM model with precise estimation of the rotor angular position. The effect of unmodeled nonlinear parameters on iron loss of PMBLDCM are regarded as disturbances for the proposed sensorless approach. A linear feedback control law with optimal current vector formulation is introduced to minimize the current ripple and torque ripple resulting in reduced copper loss. In order to select optimum switching vector considering the effect of iron loss, a model predictive control technique is proposed for the three-phase three-level neutral point clamped voltage source inverter driven PMBLDCM. The proposed sensorless predictive control (SPC) algorithm is verified both by simulation and experiments. The SPC approach demonstrates improved performance compared to the conventional approach in which the effect of iron loss is not taken into account.

Procedure for Improving the Energy, Environmental and Economic Sustainability of Transformation Houses

A procedure for improving the energy, economic and environmental sustainability of the transformation houses in low-voltage distribution networks is described in this paper. This procedure is based on the reduction of the transformer consumption, copper and core losses. Likewise, the procedure distinguishes between transformation houses with old and new transformers. The reduction of core losses, replacing transformers with others of lower power or that are more efficient, achieves significant improvements in energy and environmental aspects. The reduction of copper losses, and applying reactive compensation techniques, such as harmonic filtering and load balancing, applied in old and new transformation houses, have a greater impact on cost savings, especially when there are capacitive consumptions, as the Circular 3/2020 of the National Markets and Competition Commission of Spain determines. The procedure has been applied to an industrial transformation house, which has an old 1600 kVA transformer, resulting in significant economic savings and CO2 reductions of more than 60%, after replacing the current transformer with a more efficient one.

Flash Smelting Settler Design Modifications to Reduce Copper Losses Using Numerical Methods

A mathematical modeling approach was used to test different design modifications in a flash smelting settler to reduce the copper losses in slag, which is economically disadvantageous for copper processing using the pyrometallurgical route. The main purpose of this study was to find ways to reduce copper losses in slag by improving the settling and coalescence of copper matte droplets, in particular, the smallest droplet sizes of ≤100 µm. These improvements inside the flash smelting (FS) settler were targeted through different settler design modifications. Three different design schemes were tested using the commercial computational fluid dynamics (CFD) software, Ansys Fluent. These settler design modification schemes included the impact of various baffle types, positioning, the height inside the settler, and settler bottom inclinations. Simulations were carried out with and without coalescence and the results were compared with normal settler design. The results revealed that the settling phenomenon and coalescence efficiency were improved significantly with these design modifications. It was concluded that a single baffle design was optimal for reducing copper losses and increasing coalescence efficiency instead of using multiple baffle arrangements. The top-mounted baffle outperformed the bottom-mounted baffle and inclined settler design.

Inductor Design for Nonisolated Critical Soft Switching Converters Using Solid and Litz PCB and Wire Windings Leveraging Neural Network Model

High frequency and high efficiency inductor design method is proposed for the application of critical soft switching with large current ripple to improve the power density and efficiency of electrified energy conversion systems. Firstly for the theoretical design section, the core/coil size, number of turns, airgap, inductance are optimized to minimize the inductor losses. Secondly for the structural design section of coil, a 3D routing method of litz PCB winding is developed to reduce the AC copper losses. The strand number, trace width, thickness and layout of litz PCB are analyzed in detail. Different types of coil, including solid/litz types of PCB/wire windings, are compared and analyzed based on the high frequency copper loss reduction and space utilization. For the structural design section of core, E and I cores are optimized to reduce the volume and core losses. Specifically, E-E, E-I, I-I and E-Air types of core structures are designed and compared considering the core loss, volume reduction and airgap limitation for the stack of turns. Ten derived prototypes are built to benchmark with the commercial inductors. Power losses, temperature rise and cost are reduced by a factor of 10, 2.5 and 3 with the proposed core and coil structures.