This paper focuses on current control in a permanent-magnet synchronous motor (PMSM). This paper has two main objectives: the first objective is to develop a neural-network (NN) vector controller to overcome the decoupling inaccuracy problem associated with the conventional proportional-integral-based vector-control methods. The NN is developed using the full dynamic equation of a PMSM, and trained to implement optimal control based on approximate dynamic programming. The second objective is to evaluate the robust and adaptive performance of the NN controller against that of the conventional standard vector controller under motor parameter variation and dynamic control conditions by: 1) simulating the behavior of a PMSM typically used in realistic electric vehicle applications and 2) building an experimental system for hardware validation as well as combined hardware and simulation evaluation. The results demonstrate that the NN controller outperforms conventional vector controllers in both simulation and hardware implementation.

We designed and fabricated a multiple-ferrite-cored patch antenna (MFC-PA) to suppress harmonic radiation over the frequency range of 1 to 10 GHz and obtain wide suppressing bandwidth. Its suppression performance was compared to those of the conventional patch antenna (PA), photonic bandgap patch antenna (PBG-PA), and defected ground structure patch antenna (DGS-PA). Simulated and measured results show that MFC-PA effectively suppresses harmonic radiation up to 5.6f0, where f0 is 0.9 GHz, while the harmonic radiation of PBG-PA and DGS-PA is suppressed up to 3f0. It is suggested by the antenna performance simulation that MFC-PA can further suppress harmonic radiation up to 11f0. In principle, harmonic radiation of MFC-PA is suppressed by dissipating the unwanted signals in ferrite materials, whereas PBG-PA and DGS-PA suppress harmonic radiation by reflecting or redirecting unwanted signals, which is not desired. Ferrite loading is a unique approach to suppress any harmonic radiation.

A branch connecting two neighboring ferromagnetic α ₁ -phase rods is one of the geometric factors that contributes to degradation of alnico's normally high coercivity. This letter investigates the effects of various branch geometries and dimensions on the coercivity of alnico comprehensively by using a micromagnetic simulator when the branch is assumed to be connected in either H- or U-shaped alnico structure and the magnetization reversal of the ferromagnetic α ₁ -phase rod occurs by quasi-coherent rotation or curling. For the H-shaped structure, high coercivity is realized by adopting the middle-branch-connected (MBC) structure with a long branch length and width for quasi-coherent rotation, regardless of the branch thickness. For curling, the same geometric parameters are suggested except for a thick branch thickness. For the U-shaped structure with quasi-coherent rotation, a short branch thickness, width, and length, and MBC position lead a high coercivity. For curling, a short branch width but long length and edge-bridge-connected position result in a high coercivity, regardless of the branch thickness.

A triple-band stacked-patch antenna covering dedicated short-range communication (DSRC), fifth-generation (5G) millimeter-wave, and sixth-generation (6G) millimeter-wave frequency bands is reported for autonomous vehicles telematics applications. To show the effectiveness of the developed antenna, the antenna performances, such as the S-parameter, realized gain at boresight, and radiation patterns were simulated and measured for DSRC and 5G, and only simulated for 6G. The simulated results show good agreement with the measured results. The results show that the developed triple-band antenna can cover all three bands with high peak realized gains of 6.87 dBi, 12.3 dBi, and 19.8 dBi at DSRC, 5G, and 6G frequency bands, respectively, as well as high isolation between ports of >20 dB. The results also show a straightforward structure and higher antenna gain than the previously reported triple-band antennas in the simulation level.

We used four rotor topologies of an interior permanent magnet synchronous motor (IPMSM) to investigate the effects of remanent flux density (B_r) and coercivity (H_c) of permanent magnet on motor performance. Commercial strontium hexaferrite (SrFe₁₂O₁₉: energy product, (BH)_max, of 4.62 MGOe) and Nd-Fe-B ((BH)_max of 38.2 MGOe) magnets were used for the rotor designs. The same machine specifications and magnet volume keep constant, while the H_c and B_r vary to calculate torque and energy efficiency with the finite-element analysis. A combination of high H_c and low B_r more effectively increased maximum torque of IPMSM when the hexaferrite magnet was used. For Nd-Fe-B magnet, the same combination did not affect maximum torque, but increased energy efficiency at high speed. Therefore, the H_c value of a permanent magnet is more effective than the B_r in producing high maximum torque for SrM-magnet based IPMSM and high energy efficiency at high speed for Nd-Fe-B magnet based IPMSM.

This paper proposes a 300 kW 24-slot/10-pole 6-phase stator-shifted fractional-slot concentrated winding spoke-type ferrite permanent magnet machine for electric truck applications. The proposed motor consists of a stator with dual three-phase windings positioned 75 degrees apart to reduce higher-order MMF harmonic order, and a rotor with an inexpensive and high-resistance ferrite permanent magnet in the spoke configuration. The simulated result of the stator-shifted machine is compared with a fabricated stator-shifted machine, and the results show good agreement with each other. To further reduce the torque ripple from 2.5 to 0.9% while maintaining a high maximum torque of 2980 Nm, circular voids with a diameter of 11 mm are embedded in the rotor. The proposed motor is evaluated for irreversible demagnetization, mechanical and thermal stability, and fault tolerant ability. To assess the proposed motor performance, the electric truck simulation model is constructed using MATLAB/Simulink and used to compare with the reported 12-slot/10-pole rare-earth permanent magnet-based machine. Compared to a previously reported six-phase rare-earth permanent magnet based flat-type machine, the proposed motor can save 4.3 kWh of energy with a USD 2512 lower cost while retaining a similar motor performance.