In this letter, a two-coil wireless power transfer system is analyzed mathematically to obtain optimal source and load impedances, which are the most important factors that affect system efficiency. In addition, a near-zero refractive index metamaterial slab with a negative permeability was inserted between two resonant coils close to the transmitter to improve the efficiency in a large range. Finally, the wireless energy transfer system with the metamaterial slab was designed, fabricated and measured to evaluate the analysis method. The power transfer efficiency of 73.1% with the optimal impedances was enhanced to 81.3% using a 5 × 5 array metamaterial slab at the frequency of 13.56 MHz and the distance of 20 cm between the transmitter and the receiver.
In this paper, Hall-effect sensor faults are investigated in Sinusoidal-current-fed Permanent Magnet In-wheel Motor (PMIM) drives. And an effective methodology for their diagnostic and compensation is proposed. In particular, fault diagnostic only based Hall sensors signal, at the rising or falling edges of Hall signal, fault types of Hall sensors are diagnosed according to the specific type of Hall signal transitions and the current state of Hall signal. Fault-compensation based on reduced-order observer which has been devised to be free from the mechanical parameters (such as, inertia) in rotor position estimation process. The validity and effectiveness of the proposed methods are verified by experiments on PMIM with excessive and variable load.
Finite control set model predictive control (MPC) is one of the popular techniques for the control of power electronic converters. In this paper we explore the effect of sampling frequency in FCS-MPC of non-minimum phase converters. Usually a higher sampling frequency is linked to an improved performance. However, due to finite duration of prediction horizon in MPC and its dependence on sampling frequency we have observed that reducing the sampling frequency could improve the performance in terms of transients, efficiency and computational complexity. Based on these observations a variable frequency control scheme has also been proposed.
In this paper, a resistive-reactive series of continuous inverse modes is proposed for extending bandwidth of the series of Inverse continuous mode (SICM). A broadband class inverse F power amplifier (PA), which operates across 2.5–4.1 GHz (48.5% bandwidth), is designed by using bare GaN HEMT to prove this theory. Experiment results indicate that the PA mentioned above is able to output 9.1–18.4 W saturation power and the drain efficiency can reach 47%–75% in the whole interested band. The average output power of this designed PA is 14.2 W and the average drain efficiency is 60.1%.
This paper presents a butterfly physically unclonable function (PUF) implementation in SRAM-based field programmable gate arrays (FPGAs). To avoid output instability, we propose a delay difference test to identify reliable slices (mapped to which butterfly PUF cells are highly reliable) and then PUF reliability is significantly improved by selective mapping PUF cells to reliable slices, which is validated in experimental results.
A PSUB-strip-spatially-modulated photo detector (SMPD) and a DNW-strip-SMPD were fabricated in a standard 0.18-µm CMOS process. We analyzed and compared the bandwidth, the responsivity, and the parasitic capacitance of two PDs to provide the basis of choice for 3–5 Gbps optical receiver system. The measured responsivity and work frequency of the Psub-SMPD is 2.2 A/W and 1.8 GHz, while DNW-SMPD is 1.4 A/W and 2.9 GHz at the wavelength of 850 nm. Combined with a high performance trans-impedance amplifier and a limiting amplifier designed by us, the Psub-strip-SMPD can be used to obtain high sensitivity for the application of 3-Gbps VSR system, while for achieving the application of 5-Gbps, the DNW-strip-SMPD can be employed. Compared with other PDs recently reported, Psub-strip-SMPD and DNW-strip-SMPD exhibit the higher FOM.