Five-phase System Research Articles

Fault-Tolerant Reconfiguration Topology and Control Strategy for Symmetric Open-Winding Multiphase Machines

This paper introduces a fault-tolerant reconfiguration topology and control strategy for symmetric open-winding multiphase machines. Bidirectional switching devices are proposed to connect the inverter bridge legs on different ends when the open-circuit fault occurs, and the reconfigured circuit can regenerate the missing voltage phasors due to the faults. Furthermore, to prevent overcurrent problems on the reconfigured bridge legs and maximize the torque output capability of the reconstructed system, winding currents are optimized with zero-sequence component injection during fault-tolerant operation. The experiments implemented on the five-phase system validate that the proposed fault-tolerant scheme is effective and has higher torque output capability compared with the traditional fault-tolerant solutions.

Symmetrical Components and Sequence Networks Connections for Short-Circuit Faults in Five-Phase Electrical Systems

The method of symmetrical components is an important mathematical tool for electrical engineering, as it simplifies the analysis of unbalanced electrical circuits. The method is used almost exclusively for three-phase networks, but with the advancement of multiphase electrical systems, it could be convenient to utilize it for such systems as well. In this paper, the method of symmetrical components is used to analyze a generic five-phase electrical system for various short-circuit faults and to determine the sequence networks connections for these faults. The analysis performed covers the derivation of the symmetrical components for voltage/current and of fault currents. The analytical results and the inferred sequence networks connections are validated by computer simulations. This paper therefore extends the literature on short-circuit analysis of multiphase electrical systems using the method of symmetrical components.

High-Performance Five-Phase Axial Flux Permanent Magnet Generator for Small-Scale Vertical Axis Wind Turbine

Commonly, electrical energy is generated by using non-renewable energy such as natural gas, coal, and oil. As electrical energy is a basic asset for the development of a region, its utilization is increasing every year, which causes the existence of non-renewable energy to decrease every year. This issue is becoming a serious concern all over the world, which encourages every country to harness energy from renewable energy. Wind energy is a promising candidate for generating electricity today. In wind turbine generation, a three-phase generator is usually used. Along with the rapid development of power electronic devices and efforts to improve generator performances, the use of a multiphase system is considered important for harnessing energy from the wind more efficiently. In this study, a five-phase system is proposed to upgrade the output power and power density of the most qualified AFPMG in the previous study. The Taguchi optimization method is employed to obtain the lowest total harmonic distortion (THD) of the on-load voltage waveform. In addition to the Taguchi method, an Artificial Neural Network (ANN) is also employed to compare the results from the Taguchi method and the results are proven to have an excellent relationship. The data processed for Taguchi and ANN methods are strongly helped by using the finite element method from the Ansys Maxwell software. The performances of the proposed five-phase axial flux permanent magnet generator (FP-AFPMG) show good improvement, especially in THD, ripple torque, and ripple in the rectified voltage.

Comparative analysis of 3D‐SVM and 4D‐SVM for five ‐phase voltage source inverter

Pulse width modulation (PWM) methods play a major role to control the various power electronic converters to progress the recital of the system. In this paper, a comparative analysis is done for three dimensional space vector modulation (3D-SVM) and four dimensional space vector modulation (4D-SVM) for five-phase voltage source inverter. 3D-SVM method comprises all qualities of conventional SVM; switching time calculation is simple and much suitable for three-phase system; where in five-phase system, it has redundant switching state vectors. 4D-SVM includes advantages of 3D-SVM and other conventional methods, it employs only nonredundant switching state vectors; it directs to diminish the intricacy in switching time calculations and avoids trigonometric calculations and look up tables for reference vector identification. The various parameters such as total harmonic distortion, improved output voltage, minimized common mode voltage and switching time calculation are analyzed and compared for 3D-SVM and 4D-SVM techniques. Simulation and hardware results are acquired and established using matlab simulink and FPGA processor, respectively.

Pulse Width Modulation Switching Schemes for Two-Level Five-Phase Voltage Source Inverter

This paper proposes pulse width modulation schemes for a two-level five-phase voltage source inverter. According to the literature, the generation of a pure sinusoidal waveform requires an (n-1) number of vectors for 'n' number of phases, so in a five-phase system, a minimum of four-vectors is needed to generate a sinusoidal waveform. The author uses only two large vectors in this paper for a five-phase voltage source inverter. Vector diagram, switching table, and switching waveform have presented for two adjacent large space vectors. The performance for each PWM scheme is analyze based on fundamental components and total harmonic distortion. In last, results have verified in the Simulink environment.

Microstructures and dynamic processes within the five-phase system: regarding COVID-19 as a complex system

The research uses the development of COVID-19 in the human body as an example to explore the microstructures and dynamic processes of a concise complex system from the lens of the five-phase system. Based on the structural balance theory and system dynamics, the research finds that transitive triads and cyclic triads in the five-phase system are both imbalanced. The integration of these differentiated triads comprises of a balanced intermediate form in the shape of quadrangular cycles. These cycles serve as microstructures of the five-phase system, due to the inherent balancing feedback mechanism, and support the generation of resultants. The alternation of quadrangular cycles drives the spiraling development of the whole system. By orderly and regular interweaving of signed directed links, the research provides a holistic, process-oriented demonstration for the development processes of COVID-19. It clarifies that the essence of the five-phase system is phase-transition processes with the quadrangular cycle as carrier and supporter, rather than the static aggregation of five elements. The research deepens the understanding of system nonlinearity by visualizing the circular causality and promotes the academic dialogue between the Western process theory and the Chinese inherited notion of the five-phase system.

A Built-In High Temperature Half-Bridge Power Module with Low Stray Inductance and Low Thermal Resistance for In-Wheel Motor Application

In order to integrate a five-phase inverter system into the limited space of an in-wheel motor, a high temperature low stray inductance SiC half-bridge power module with a volume of about 5 ml was designed, fabricated and tested. The stray inductance in the module was calculated by an electromagnetic simulator and confirmed by measurements to be 4.4 nH. Double-pulse switching tests were conducted at temperatures up to 200°C. Thermal resistance, including that of the substrate, was calculated to be 0.153 °C/W. Fast switching capability was accomplished with an external gate resistance of 1 Ω.

Analysis of five‐phase voltage source inverter with dual frequency modulator

This study presents an analysis of five-phase voltage source inverter with dual frequency modulator to reduce baseband harmonics distortion. Analyses of five-phase inverter load equation, error signal, system stability and states bounds are carried out. Further, the frequency domain analysis shows the noise shaping effect of the proposed dual frequency modulator. Three design examples with first, second and forth order dual frequency modulators are shown. Both simulations and experiments are illustrated, telling that the proposed modulator can reduce baseband harmonics distortion as discussed in the frequency domain analysis. Further, the states bounds obtained from simulations agree with the theoretical value, showing the correctness of the analysis. Both simulations and experiments correspond to each other, confirming the effectiveness of the proposed five-phase inverter driven by dual frequency modulator.

Five‐phase travelling wave induction heater for continuous heating of flat material

This study proposed a novel travelling wave induction heating system with five-phase exciting current. The proposed system used special exciting current to obtain a homogeneous eddy current density, which affects the temperature pattern over the material surface. Five-phase system has been attracted from many industrial applications due to its inherent features compared to the three-phase system. An even number of phases is not preferred because the poles exchange with each other. A comparison investigation with other traditional methods is represented to realise the features of the proposed method. A finite-element method simulation is represented by using ANSYS 15®; the simulation results show that the proposed system gives superior performance of energy transferred, uniform heat distribution and higher power factor over that of the traditional three-phase system. Moreover, it performs identical eddy current, power densities, temperature and efficiency to that of the six-phase system with profits of reduction in size, weight, cost and winding copper losses.

Ammoniacal leaching and recovery of copper from alloyed low-grade e-waste

The paper concerns a hydrometallurgical method for selective recovery of copper from low-grade electric and electronic wastes. The following consecutive stages were proposed: smelting of the scraps to produce Cu–Zn–Ag alloy, leaching of the alloy in ammoniacal solution, and selective copper electrowinning. Cu–Zn–Ag alloy was a polymetallic and five-phase system. It was leached in chloride, carbonate, sulfate and thiosulfate solutions. This resulted in the separation of the metals, wherein metallic tin and silver as well as lead salts remained in the slimes, while copper and zinc were transferred to the electrolyte. Copper was selectively recovered from the ammoniacal solutions by the electrolysis, leaving zinc ions in the electrolyte. The best conditions of the alloy treatment were obtained in the ammonia–carbonate system, where the final product was copper of high purity (99.9 %) at the current efficiency of 60 %. Thiosulfate solution was not applicable for the leaching of the copper alloy due to secondary reactions of the formation of copper(I) thiosulfate complexes and precipitation of copper(I) sulfide, both inhibiting dissolution of the metallic material.

A New Control Strategy of Five-Phase Permanent-Magnet Motor Drives with a Third Harmonic Current Injection

In this paper, a five-phase permanent-magnet (PM) brushless dc (BLDC) motor is investigated, which has almost trapezoidal back electromotive force(EMF) due to its concentrated windings. Since the third harmonic component in the magnetic field is utilized, the presented five-phase BLDC motors have a higher torque density over conventional three-phase ones, in which the third harmonic current is injected. This paper proposes a new five-phase transformation system, by which the vector control is easily applicable to five-phase BLDC motors. Finally, the results verify the validity of the proposed method.

Steady-state performance assessment of three- and five-phase permanent magnet generators connected to a diode bridge rectifier under open-circuit faults

Small-scale wind turbines often utilise permanent magnet generators that supply power via an uncontrolled diode rectifier. In such systems, a custom generator design is required to optimise the aerodynamic and electromechanical performance; therefore the phase number of the generator is not restricted. This study assesses and compares the performance of prototype 700 W five- and three-phase permanent magnet generators connected to a diode bridge rectifier and their performance under open-circuit fault conditions. The simulation and experimental results demonstrate that the five-phase system can utilise a smaller DC-link capacitor and develops lower shaft torque ripple compared to the three-phase system. The three-phase generator can only tolerate one single-phase open-circuit failure. However, three possible open-circuit phase failure modes are considered in the five-phase machine: a single open-circuit phase and two open-circuit phases, where the two phases can be adjacent or non-adjacent. It is shown that the shaft torque ripple and output power are superior in the five-phase system with both the single-phase failure mode and the non-adjacent phase failure mode compared to the three-phase system with a single-phase failure. However, the adjacent phase failure mode is more extreme and generates less output power than the three-phase system. Simulation and finite-element analysis results are verified by experiments on the prototype 30-slot, four-pole, double-layer, surface-mounted permanent magnet generator.

Hydrometallurgical recovery of copper and cobalt from reduction-roasted copper converter slag

The paper is concerned with a simple hydrometallurgical method for selective recovery of copper and cobalt from industrial copper converter slag. The following consecutive stages are proposed: roasting of the slag in reduction conditions to produce Cu–Co–Fe–Pb alloy, electrolytic dissolution of the alloy in an ammonia–ammonium chloride solution, ammoniacal leaching of the slime, selective copper and cobalt electrowinning. Cu27–Co6–Fe64–Pb1.5 alloy was a five-phase system and did not dissolve uniformly during electrolysis. This resulted in the separation of the metals, wherein iron remained in the slime, while copper and cobalt were components of slime, electrolyte and cathodic deposit. A mechanism of the alloy dissolution was developed. A series of secondary processes took place in the system: precipitation of iron compounds, copper cementation with cobalt and iron; adsorption of copper and cobalt ions on the iron precipitates. Final products were metals of high purity (99.9% Cu, 92% Co).

Fault-Tolerant Interior-Permanent-Magnet Machines for Hybrid Electric Vehicle Applications

Multiphase interior permanent magnet (IPM) motors are very good candidates for hybrid electric vehicle applications. High torque pulsation is the major disadvantage of most IPM motor configurations. A five-phase IPM motor with low torque pulsation is discussed. The mathematical model of the five-phase motor is given. A control strategy that provides fault tolerance to five-phase permanent-magnet motors is introduced. In this scheme, the five-phase system continues operating safely under loss of up to two phases without any additional hardware connections. This feature is very important in traction and propulsion applications where high reliability is of major importance. The system that is introduced in this paper will guarantee high efficiency, high performance, and high reliability, which are required for automotive applications A prototype four-pole IPM motor with 15 stator slots has been built and is used for experimental verification.

Surface Plasmon Resonance Spectroscopy of Dielectric Coated Gold and Silver Films on Supporting Metal Layers: Reflectivity Formulas in the Kretschmann Formalism

In surface plasmon resonance (SPR) studies of thin films, a binder metal (Cr, W, or Ti) is often used to support the SPR-active gold or silver substrate on a glass prism. The optical response of the SPR device is affected by such binder layers, and in the analysis of experimental data, it is necessary to account for these effects. The present report examines the theoretical considerations for SPR spectroscopy involving these types of supported substrates. It is shown that usually, the binder effects are weak in the neighborhood of the resonance angle. In the same region, the SPR plot exhibits an approximately Lorentzian behavior and is characterized here by extending the previously known Kretschmann formalism to a five-phase system. The calculations lead to a set of analytical formulas, indicating the limiting factors of the binder metal and expressing the reflectivity of the multilayer structure in terms of the thickness and dielectric function of the sample layer. In addition, these formulas explicitly show how the characteristic features of SPR plots are governed by certain experimental variables. The calculations provide a relatively simple framework for analyzing the results of SPR studies that focus primarily on resonance angle measurements.

Comparing the value of Southern Oscillation Index-based climate forecast methods for Canadian and US wheat producers

Southern Oscillation Index (SOI) based forecasting methods are compared to determine which method is more valuable to Canadian and US wheat producers. Using decision theory approach to valuing information, the more commonly used three-phase method of El Niño, La Niña, and other is compared to a five-phase system. Because of differences in growing season and yearly SOI classification schemes, two different three-phase methods are used. The five-phase system is based on the level and rate of change of the SOI over a 2 month period. Phases are consistently negative, consistently positive, rapidly falling, rapidly rising, and near zero. As expected, results vary by the method used. Winter wheat producers in Illinois place no value on either of the SOI-based forecasting systems. Producers at seven of the 13 sites prefer the five-phase method over either of the three-phase method (spring wheat producers in Manitoba, Alberta, North Dakota and South Dakota, along with winter wheat producers in Oklahoma, Texas, and Washington). The value of the five-phase approach is up to 70 times more valuable than the three-phase approach. Producers growing spring wheat in Saskatchewan and Montana, along with winter wheat producers in Ohio and Kansas value the three-phase approach more than the five-phase. In this case, the value of the three-phase system is up to two times more valuable than the five-phase system. Depending on expected price and region, the values of the SOI-based forecasts range from 0 to 22% of the value of perfect forecasts. In both absolute and percentage of perfect forecasts, producers in Oklahoma, Texas, Manitoba, Saskatchewan, and South Dakota value either system more than producers in the remaining regions. Economic value and distributional aspects of the value of climate forecasts have implications for producers, policy makers, and meteorologists. Finally, the results clearly suggest all producers will not prefer one forecast type. Forecasts need to be tailored to specific regions.

Negative Degrees of Freedom and the Phase Rule

THE first part of Brynestad's comments on our communication1 is concerned with the 1-component system: two solids, liquid and vapour. We mentioned this in our original paper2 only in passing, since we could not cite any example for discussion. Brynestad's comment raises an issue which we did not consider, namely, if such a system existed, whether the relative amounts of the two solid phases present would be in a fixed ratio. Brynestad, following Ricci3, cites the case of d- and l-sodium chlorate. Before we turn to this interesting case, let us first examine Brynestad's analysis of a system which we did discuss in our original article, namely, a 2-component, five-phase system. We cited a number of ‘near misses’ such as the system mercury (m.p. − 38.9°) and diethylaniline (− 38.8°) and said that deuteration of the organic moiety in this and in other examples of ‘near misses’ could conceivably bring the triple points of the two components into exact coincidence. We interpreted Brynestad's original remarks4 to mean that the chance of such a system existing was comparable to the chance of failure of the second law of thermodynamics. We see now that Brynestad did not mean this and that he does not rule out the possibility of such systems existing. He goes on to say that ‘most probably the two solids would occur in fixed proportions’. We do not believe this to be correct for reasons given as follows. Moreover, Brynestad claims that the system would be ‘a normal 4-phase system’. To say that solid mercury and solid diethylaniline are thermo-dynamically the same phase is to so alter the meaning of ‘phase’ as to derive it of any further value. One can easily trace the reasoning leading up to this conclusion: the phase rule is true; the mercury system + diethylaniline (for example) would, if considered to have five phases, imply a negative degree of freedom; negative degrees of freedom are not possible; therefore, at least two of the phases must be thermodynamically the same. To us it makes more sense to concede that negative degrees of freedom are possible; their existence is easily explained and the phase rule is not violated. We turn now to the system: d-NaClO3(c) + l-NaClO3(c) + melt + vapour.