Design and control system of inverter-driven permanent magnetsynchronous motors for high torque operation

This work describes a current vector control method for permanent magnet (PM) synchronous motors suitable for high-torque operation. The current phase angle is controlled according to load conditions in order to use the reluctance torque effectively. Characteristics such as torque, efficiency, power capability and so on are greatly improved by this control method in comparison with the conventional control method. The performance characteristics are greatly affected by the motor parameters, which depend on the rotor configurations and permanent magnet geometries. The available maximum torque and power capability are also examined for the several types of PM motor, taking into consideration the inverter capacity. The tendency toward magnetic saturation and demagnetization of the permanent magnet is also examined     

Asymmetric <Emphasis Type="Italic">in vitro</Emphasis> synthesis of diastereomeric phosphatidylglycerols from phosphatidylcholine and glycerol by bacterial phospholipase D

Using chiral-phase HPLC, we determined the stereochemical configuration of the phosphatidylglycerols (PtdGro) synthesized in vitro from 1,2-diacyl-sn-glycero-3-phosphocholine (PtdCho, R configuration) or 1,2-diacyl-sn-glycero-3-phosphoethanolamine (PtdEtn, R configuration) and glycerol by transphosphatidylation with bacterial phospholipase D (PLD). The results obtained with PLD preparations from three Streptomyces strains (S. septatus TH-2, S. halstedii K5, and S. halstedii subsp. scabies K6) and one Actinomadura species were compared with those obtained using cabbage and peanut PLD. The reaction was carried out at 30°C in a biphasic system consisting of diethyl ether and acetate buffer. The resulting PtdGro were then converted into bis(3,5-dinitrophenylurethane) derivatives, which were separated on an (R)-1-(1-naphthyl)ethylamine polymer. In contrast to the cabbage and peanut PLD, which gave equimolar mixtures of the R,S and R,R diastereomers, as previously established, the bacterial PLD yielded diastereomixtures of 30–40% 1,2-diacyl-sn-glycero-3-phospho-1′-sn-glycerol (R,S configuration) and 60–70% 1,2-diacyl-sn-glycero-3-phospho-3′-sn-glycerol (R,R configuration). The highest disproportionation was found for the Streptomyces K6 species. The present study demonstrates that bacterial PLD-catalyzed transphosphatidylation proceeds to a considerable extent stereoselectively to produce PtdGro from PtdCho or PtdEtn and prochiral glycerol, indicating a preference for the sn-3′ position of the glycerol molecule.     

Broiler-house environment monitoring system using sensor network and mail delivery system

In this paper, we propose the system that combines the sensor network with the mail delivery system to construct the system that observes an environmental change of the broiler-house. As a result of hearing of the producer, the environment system needs to able to be observed some broiler-houses, to inspect the summary data from the cellular phone, and to transmit the warning mail in a rapid temperature change. A basic part of the system is a sensor network by the sensor module that we developed. Only the sensor modules are put in the each broiler-house, and the network by wireless LAN communication is constructed, because the system needs to watch of two or more broiler-houses, and it is difficult to setup a large-scale system at the broiler-house. The always-connected high-speed Internet is preferable to accumulate, to process data, and to offer it to the user in a comprehensible form. But, it is difficult to build always-connected high-speed Internet at the chicken farm which is used by experiment. The server is set up in the remote place, and we propose the system that delivers data from the chicken farm with mail. The verification of the effectiveness of the proposed system and the problem are examined by actually setting up the system that proposes it in the broiler-house, and operating it. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Optimal frequency tracking method for phase‐shift PWM inverter

This paper proposes a new resonant frequency tracking control method for full‐bridge‐type high‐frequency inverters. Whereas the ordinary phase‐locked loop (PLL) based frequency control method uses a current sensor and a voltage sensor, the proposed technique can achieve the same purpose with a single current sensor. In high‐frequency power supply systems using a PLL, it is impossible to perform power control with an inverter. Therefore, an active converter must be used for power control, and the system grows larger. On the other hand, high‐frequency inverters using the proposed control system simultaneously enable power control and achieve the same resonant frequency tracking as a PLL, and thus high‐frequency power supply systems become extremely simple. This paper explains in detail the principle underlying the control method, and presents an example of a circuit to realize it. The theory is backed up by using a prototype high‐frequency power supply system which actually employs the proposed control system, thereby demonstrating its practical utility in industry. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Stress-strain relations of steel fiber reinforced concrete under repeated compressive load

The purpose of the present paper is to examine the hysteretic stress-strain behavior of steel fiber reinforced concrete and steel fiber reinforced mortar under uniaxial compression and to propose mathematical expressions of stress-strain curves based on experimental data. The stress-strain relations are examined in terms of the volume fraction and the aspect ratio of steel fiber. It is indicated in this paper that the normalized stress - strain curves can be described by the proposed simple numerical model with a fairly good accuracy.     

Computations of probabilistic output admissible set for uncertain constrained systems

This paper considers uncertain constrained systems, and develops two algorithms for computing a probabilistic output admissible (POA) set which is a set of initial states probabilistically assured to satisfy the constraint. The first algorithm is inspired by an existing randomized sequential technique. The second algorithm alleviates the computational effort based on heuristics. The present algorithms terminate in a finite number of iterations and provide a POA set. Additionally, we can obtain information on the size of the resulting set a posteriori. A numerical simulation demonstrates the applicability of the POA set to a control system design scheme.     

Isolation and Identification of Antihypertensive Peptides from Antarctic Krill Tail Meat Hydrolysate

ABSTRACT:  Antarctic krill ( Euphausia superba ) obtained from the huge biomass in Antarctic waters is an important food product in Japan. Antarctic krill peptide powder (AKPP) prepared from the tail meat by enzymatic hydrolysis significantly decreased the systolic blood pressure in spontaneously hypertensive rats by a single oral administration (1, 10, or 100 mg). Presumably, the effect of AKPP was through inhibition of the conversion of angiotensin, which mediates blood pressure elevation, from its inactive propeptide to the mature angiotensin. Two potent angiotensin I-converting enzyme (ACE) inhibitory peptides were isolated from AKPP by high-performance liquid chromatography (HPLC) and identified as Val-Trp (IC₅₀= 2.75 μg/mL; 12.9 μM) and Leu-Lys-Tyr (IC₅₀= 4.26 μg/mL; 10.1 μM). Val-Trp and Leu-Lys-Tyr comprised 0.025%± 0.0023% (w/w) and 0.018%± 0.0023% (w/w) of AKPP, respectively, as measured by electrospray ionization mass spectrometry (ESI-MS). The contributions of Val-Trp and Leu-Lys-Tyr to the ACE inhibitor activity of AKPP were 17.7%± 1.60% and 8.04%± 1.03%, respectively, suggesting that these 2 peptides constitute a substantial portion of the overall ACE inhibitor potential of AKPP.