Circuit Analysis and Characterization of Contactless Power Transfer System with Variable Impedance

A contactless power transfer system using a repeater coil (repeater Coil topology) has been proposed as a method of suppressing overcurrent without power control during misalignment or no‐load. By installing a repeater coil between the primary and secondary coils, it is possible to increase the input impedance in the case of misalignment of the secondary coil or no‐load condition. In addition, another contactless power transfer system using primary parallel and secondary series resonance capacitors (PS capacitor topology) has been proposed. In the PS capacitor topology, the input impedance can be increased during misalignment of the secondary coil or no‐load condition similar to the repeater coil topology. In this paper, we evaluated the characteristics of both these topologies. First, we conducted a circuit analysis of the repeater coil topology and proposed a design method. In addition, we theoretically clarified the characteristic difference of the two topologies and experimentally evaluated the characteristics.     

Fundamental Research on Control Method for Power Conversion Circuit of Wireless In‐Wheel Motor Using Magnetic Resonance Coupling

The in‐wheel motor (IWM) is the most preferred driving mechanism of electric vehicles for its advantages of vehicle motion control, energy efficiency, and vehicle design flexibility. One of the technical problems of the IWM is the reliability of power and the signal wires. Wireless power transfer technology is the best solution to this problem. In this paper, a bidirectional wireless power transfer circuit using a primary inverter and a secondary converter is proposed. We propose a control method for both the inverter and the converter to stabilize the secondary dc‐link voltage. The proposed method is verified by simulation and experiment using simulated test equipment.     

Research on Maximizing Power Transfer Efficiency of Wireless In‐Wheel Motor by Primary and Load‐Side Voltage Control

The authors have developed a wireless power transfer (WPT) system for an in‐wheel motor (IWM). It is called a wireless in‐wheel motor (W‐IWM). This paper presents a method that enhances the WPT efficiency in this system. Some methods that maximize the power transfer efficiency by power converter control have been proposed in the past WPT research. In this research, a dc‐dc converter is inserted on the receiver side to vary the load state. However, the space on the receiver side is very small for the W‐IWM; therefore, it is preferable to make the secondary circuit small. Therefore, a full bridge converter is used instead of a dc‐dc converter in the W‐IWM. In this paper, the authors propose a theoretical formula for the transfer efficiency of the IW‐IWM. From an analysis of this formula, there is a combination of a primary voltage and load voltage that maximize the efficiency. The feasibility is validated by an experiment using a motor bench set.     

SUBSTRATE SPECIFICITY OF AMINOPEPTIDASE FROM JAPANESE CLASSIFIED BARLEY FLOUR

In this study, some properties of a peptidase obtained from Japanese barley were investigated. Boc‐Val‐Leu‐Lys‐MCA was slightly hydrolyzed, but the enzyme showed almost no activity on Suc‐Ala‐Ala‐Pro‐Phe‐MCA and Ac‐Val‐Glu‐Ile‐Asp‐MCA. The enzyme activity decreased to 57.7% by the addition of 0.235 mM bestatin. All tripeptides and tetrapeptides studied were cleaved from the N‐terminus amino acid by the enzyme. However, the enzyme did not cleave Leu‐Pro‐Phe‐Phe‐Asp in the manner of the AP type. The C‐terminus amino acid residue (Asp) and the second amino acid residue of the C‐terminus (Phe) were released at almost the same time. From these findings, this enzyme was identified as both an AP and oligopeptidase. This property is very similar to that of cathepsin H and the novel peptidase purified from mesquite pollen. This enzyme may not only supply useful foodstuffs such as a meat tenderizer but also produce bioactive peptides.     

Microbicidal effect of hydrostatic pressure on satsuma mandarin juice

Six microbial strains were inoculated into Satsuma mandarin ( Citrus unshiu Marc. ) juices and the effects of hydrostatic pressure on their viability were examined. Five micro-organisms were substantially inactivated under 400 MPa at room temperature for 5 min whereas B. subtilis survived. the effects achieved by treating at 57°C under 100 MPa for 5 min were comparable to those achieved by treating under 400 MPa at room temperature for 5 min. Pectin esterase was not inactivated even after treating at 600 MPa and 57°C for 5 min. Although the high pressure treatment exerted hardly any effect on juice chemical components, the pulp particle size distribution was slightly changed by treating under 600 MPa at room temperature for 30 min. Pressure treatment had little effect on the volatile flavour components.     

BI CONCENTRATION DEPENDENCE OF STRUCTURAL,FERROELECTRIC AND MAGNETIC PROPERTIES OF BiFeO3FILMS

ABSTRACT

Bi-rich BiFeO₃ films were fabricated by chemical solution deposition followed by a post-deposition annealing at 823 K in air. Not only the polycrystalline BiFeO₃ phase but also the bismuth oxide phases were formed at high excess Bi contents. This suggested that the Bi atoms were not significantly evaporated. The remanent polarization decreased as the excess Bi contents increased at 90 K, though the remanent polarization of 33 μ C/cm² was still obtained at the excess Bi contents of 30 at.%. The magnetization monotonically decreased as the excess Bi content increased. It could be considered that the optimal Bi content is the stoichiometric value of BiFeO₃ in the preparing way of the CSD followed by the annealing at 823 K.     

Discrete variable stochastic approximation procedures and recursive autoregressive model identification

Two stochastic approximation procedures are proposed for finding a point attaining the maximum of a regression function defined and observable only at points on a set of discrete variables. The asymptotic convergence property of the procedures is discussed using the theorem of almost supermartingales. The procedures are applied to the recursive identification of autoregressive time series models. The identification procedure consists of a recursive order estimation stage and a recursive autoregressive parameter updating stage, and gives the true autoregressive model or the best autoregressive approximation model.