Five-phase Synchronous Reluctance Machines Equipped with a Novel Type of Fractional Slot Winding

Multi-phase machines are so attractive for electrical machine designers because of their valuable advantages such as high reliability and fault tolerant ability.Meanwhile,fractional slot concentrated windings(FSCW)are well known because of short end winding length,simple structure,field weakening sufficiency,fault tolerant capability and higher slot fill factor.The five-phase machines equipped with FSCW,are very good candidates for the purpose of designing motors for high reliable applications,like electric cars,major transporting buses,high speed trains and massive trucks.But,in comparison to the general distributed windings,the FSCWs contain high magnetomotive force(MMF)space harmonic contents,which cause unwanted effects on the machine ability,such as localized iron saturation and core losses.This manuscript introduces several new five-phase fractional slot winding layouts,by the means of slot shifting concept in order to design the new types of synchronous reluctance motors(SynRels).In order to examine the proposed winding’s performances,three sample machines are designed as case studies,and analytical study and finite element analysis(FEA)is used for validation.

The Study of Demagnetization of the Magnetic Orientation of Permanent Magnets for IPMSM with Field-Weakening Control under Hot Temperature

In this study, we investigate the demagnetization resistance of a concentrated winding IPMSM （interior permanent magnet synchronous motor） accounting for field weakening control by changing the magnetization direction of the permanent magnet under a high-temperature environment. IPMSMs are investigated by FEA （finite element analysis） using the same volume of the permanent magnet while changing the magnet’s width, thickness and magnetic field orientation angle. FEA found that a V-shaped angle Va = 100° and a changed magnet length of 97% using an oblique magnetic-field-oriented magnet strike a good balance between demagnetization resistance and torque at 180 ℃. Comparison between demagnetization of negative d-axis current （current phase β = 90°） and demagnetization of field weakening control （β = 80°） using concentrated winding IPMSM with V-shaped angle Va = 100° is conducted. With the demagnetization factor at β = 80° for β = 90°, the demagnetization factor 0.39 （2.6 times） at α = 0° decreases to 0.23 （4.3 times） at α = 20°. The demagnetization resistance in the field weakening control is further improved.

Capacity-operation collaborative optimization of the system integrated with wind power/photovoltaic/concentrating solar power with S-CO_(2) Brayton cycle

This paper proposes a new power generating system that combines wind power(WP),photovoltaic(PV),trough concentrating solar power(CSP)with a supercritical carbon dioxide(S-CO_(2))Brayton power cycle,a thermal energy storage(TES),and an electric heater(EH)subsystem.The wind power/photovoltaic/concentrating solar power(WP-PV-CSP)with the S-CO_(2) Brayton cycle system is powered by renewable energy.Then,it constructs a bi-level capacity-operation collaborative optimization model and proposes a non-dominated sorting genetic algorithm-Ⅱ(NSGA-Ⅱ)nested linear programming(LP)algorithm to solve this optimization problem,aiming to obtain a set of optimal capacity configurations that balance carbon emissions,economics,and operation scheduling.Afterwards,using Zhangbei area,a place in China which has significant wind and solar energy resources as a practical application case,it utilizes a bi-level optimization model to improve the capacity and annual load scheduling of the system.Finally,it establishes three reference systems to compare the annual operating characteristics of the WP-PV-CSP(S-CO_(2))system,highlighting the benefits of adopting the S-CO_(2) Brayton cycle and equipping the system with EH.After capacity-operation collaborative optimization,the levelized cost of energy(LCOE)and carbon emissions of the WP-PV-CSP(S-CO_(2))system are decreased by 3.43%and 92.13%,respectively,compared to the reference system without optimization.

Magnetomotive Force Harmonic Reduction Techniques for Fractional-Slot Non-Overlapping Winding Configurations in Permanent-Magnet Synchronous Machines

Compared to conventional distributed winding configurations,the fractional-slot non-overlapping(concentrated)windings exhibit advantages such as short end-winding length,high copper packing factor(particularly with segmented stator structure),low cogging torque,good field weakening capability owing to relatively large d-axis inductance,and better fault tolerant capability due to low mutual inductance.However,one of the key problems of employing concentrated windings in Permanent-magnet Synchronous Machines(PMSMs)is the high eddy-current losses in rotor magnets and/or rotor iron due to the presence of a large number of lower and higher order space harmonics in the stator Magneto-Motive Force(MMF).These MMF harmonics also result in other undesirable effects,such as acoustic noise and vibrations,and localized core saturation which tend to reduce reluctance torque.This paper reviews the current state-of-the-art of the MMF harmonic reduction techniques for concentrated winding configurations in PMSMs,including winding split and shift,delta-star connected windings,multiple 3-phase windings,multilayer windings,uneven turn numbers,and stator flux barriers.Their concepts,advantages and disadvantages are presented and assessed.