HALF-SPACE GREENS'S FUNCTION DUE TO A SPATIALLY HARMONIC LINE LOAD AND SCATTERED FIELDS IN THE FAR FIELD REGION

Half-space Green's function due to a spatially harmonic line load has been expressed as a sum of the full-space Green's functions and a 2-D integral representation of the reflected waves by the free surface of the half-space.By using the obtained half-space Green's function,an integral rep- resentation of the scattered waves by a cylindrical obstacle is then derived.Finally,by analyzing the far-zone behavior of the integrands of the integral representation.the far-field pattern of the scattered waves in a half-space obtained.

Laser phase effect on asymmetric harmonic distribution in H_2^+

The laser phase effect on the spatial distribution of the molecular high-order harmonic generation（MHHG） spectrum from H_2~＋ is theoretically investigated through solving the Non-Bohn-Oppenheimer（NBO） time-dependent Schrodinger equation（TDSE）.The results are shown as follows,（i） The generated harmonics from the two nuclei each present an asymmetric distribution.Particularly,when the laser phases are chosen from 0.0π to 0.6π and from 1.7π to 2.0π,the contribution from the negative-H plays a main role in harmonic generation.When the laser phases are chosen from 0.7πto 1.6k,the contribution from the positive-H to the harmonic generation is remarkably enhanced and becomes greater than that from the negative-H.The electron localization,the time-frequency analyses of the harmonic spectrum and the time-dependent wave function are shown to explain the asymmetric harmonic distribution in H_2~＋,which provides us with a method to control the electron motion in molecules,（ⅱ） As the pulse duration increases,the asymmetric distributions of the MHHG in two H nuclei decrease,（ⅲ） Isotope investigation shows that the asymmetric harmonic distribution can be reduced by introducing the heavy nucleus（i.e.,D_2~＋）.

Spectral redshift of high-order harmonics by adding a weak pulse in the falling part of the trapezoidal laser pulse

We investigate the spectral redshift of high-order harmonics of the H_2~＋（D_2~＋） molecule by numerically solving the non-Born–Oppenheimer time-dependent Schr ¨odinger equation（TDSE）. The results show that the spectral redshift of highorder harmonics can be observed by adding a weak pulse in the falling part of the trapezoidal laser pulses. Comparing with the H_2~＋ molecule, the shift of high-order harmonic generation（HHG） spectrum for the D_2~＋ molecule is more obvious.We employ the spatial distribution in HHG and time-frequency analysis to illustrate the physical mechanism of the spectral redshift of high-order harmonics.

Analytical Analysis and Performance Characterization of Brushless Doubly Fed Induction Machines Based on General Air-gap Field Modulation Theory

Air-gap magnetic field modulation has been widely observed in electric machines.In this study,we present an analytical analysis and performance characterization of brushless doubly fed induction machines(BDFIMs)fed by two independent converters from the perspective of air-gap field modulation.The spiral-loop winding is studied in detail as an example to show the generalized workflow that can also be used to analyze other short-circuited rotor winding types,such as nested-loop and multiphase double-layer windings.Magnetic field conversion factors are introduced to characterize the modulation behavior of special rotor windings and facilitate their comparison in terms of cross-coupling capability,average torque,and harmonic content of the air-gap flux density waveforms.The stator magnetomotive force(MMF),rotor MMF,and resultant air-gap MMF are considered,based on which the closed-form inductance formulas are derived,and the torque equation is obtained along with the optimal current angle for maximum torque operation by using the virtual work principle.The design equations are then developed for the initial sizing and geometry scaling of the BDFIMs.Transient finite element analysis and experimental measurements are performed to validate the analysis.

A Virtual Prototyping Approach for Development of PMSM on Real‑Time Platforms: A Case Study on Temperature Sensitivity

This paper presents a comprehensive evaluation of system interactions in a battery electric vehicle caused by temperature sensitivity of permanent magnet synchronous machines(PMSM).An analytical model of a PMSM considering iron losses and thermal impact is implemented on a field programmable gate array suitable for hardware-in-the-loop testing.By the presented virtual prototyping approach,different machine characteristics defined by the design are used to parameterize the analytical model.The investigated temperature effect is understood as an interacting influence between machine character-istics and control,which are investigated in terms of torque generation,voltage utilization and efficiency under closed-loop condition in a vehicle environment.In particular,using a surface permanent magnet rotor and an interior permanent magnet rotor,the performance of both machine designs is analyzed by varying temperature-adjusted feedforward control strategies on the basis of a driving cycle from a racetrack.The comparison shows that the machine design with surface-mounted mag-nets is associated with higher temperature sensitivity.In this case,the temperature consideration in the feedforward control provides a14%loss reduction in closed-loop vehicle test operation.It can be summarized that the electromagnetic torque is less sensitive to a temperature variation with increasing reluctance.The presented development approach demonstrates the impact of interactions in electric powertrains without the need of real prototypes.