A Driving Method of a Spuare Waveform Inverter Circuit Using Power Transistors

In recent years, the development of a high power transistor element is proceeding. A high power inverter circuit using power transistors are finding a good number of applications in induction heating and melting. Turn off time of power transistors occupies 5-lOμs of switching characteristics. A driving method to give base inputs for a half period is widely used for a inverter circuit. But this method has the following defects, the short-circuit current flows through two transistors because the other pair transistors turn on before one pair transistors turn off. So the switching loss is increased, the maximum output and the efficiency are decreased. In this paper, a driving method to give base inputs for the less period as compared with a half period is discussed. Using this method, the foregoing defects is lost and the driving frequency is able to become higher. In addition, it become clear that the square waveform output is given using this method in the case of R-L load

Basic Characteristics of Squarewave Irwerter Circuit with Series R-L Load

In this paper, the steady state operations of the squarewave inverter circuit with a series R-L load are discussed. The circuit consists of transistors and feedback diodes. The basic equation is derived from its equivalent circuit. Solving the basic equation with steady state conditions, the instaneous value of the load current i is derived. The period t(2) for which the current flows from the supply to the load and the period t(l) for which the current feedbacks through diodes from the load to the supply are calculated from (i), and the ratio of t(l) to t(2) is illustrated using power factor of fundamental wave, pf, as a variable. The ratios of transistor mean current I(tr), diode mean current I(D), supply mean current I(s) to the load current I are illustrated using pf as a variable, too. In result, each current ratios to I is shown in simple expressione. The load current can be calculated simply using the coefficient reading off the figure. In addition, it becomes clear from the figure that the load current is scarcely influenced by the harmonic voltage in less than 0.8 of pf. The ratio t(2)/(t(1)+t(2)) calculated in squarewave voltage, shows the limit of pulse width control whose out put voltage is the squarewave

Neutrinoless Double Beta Decay and <η><\eta> Mechanism in the Left-Right Symmetric Model

The neutrinoless double beta ($0\nu\beta\beta$) decay is studied in the framework of left-right symmetric model. The coexistence of left and right handed currents induces rather complicated interactions in the mixing of lepton and hadrons, called $$mechanism and$$ mechanism in addition to the conventional effective neutrino mass $$mechanism. In this letter we indicate the possible magnification of$$ mechanism and importance to survey $0\nu\beta\beta$ decay of different nuclei for specifying New Physics beyond the Standard Model.Comment: 13 pages, 2 figure

The Wiedemann Effect of the Magnetostriction Alloy "Alfer" at High Temperatures

The Wiedemann effect of "Alfer" (12.91 per cent Al-Fe alloy) was measured with the annealed specimen at high temperatures. As the temperature rises, the effect gradually decreases at the constant current through the specimen, and also the higher the temperature is, the weaker the field is for the maximum effect. When the current through the specimen as well as the longitudinal field is constant, the effect gradually decreases with the rise of temperature, and bcecomes extremely small at the magnetic transformation point of the Fe_3Al superlattice, and vanishes at the magnetic transformation point of α phase. The effect of Ni and Fe was measured to compare with that of Alfer. The temperature dependence of the effect of Ni is similar to that of Alfer, but that of Fe is different from both, that is, it gradually increases as the temperature rises, and after reaching a maximum at about 600℃, rapidly decreases, becoming zero at the magnetic transformation point

Frequency-Domain Model Order Reduction of Electromagnetic Field in Induction Motor

A model order reduction (MOR) method for an induction motor using a Cauer ladder network (CLN) is developed in the frequency domain. A multiport frequency transformation between the stator and mover domains is derived by neglecting the spatial harmonic interactions. Even after neglecting the harmonic interactions, the reduced model provides a reasonably accurate frequency response, which is more accurate than that of the conventional approximated equivalent circuit

Assembly Sequence Planning by Probabilistic Tree Transformation

Various types of computer systems including CAD/CAM systems have been introduced in machine industry. Some of the systems can handle assembly sequence planning, however it requires long time for planning. This paper proposes a method of generating assembly sequences efficiently. This method extracts some parts and/or subassemblies whose possibilities of being removed from a product are strong, and tests whether they can be removed without any geometric interference. By performing these operations repeatedly, the method generates a disassembly sequence of the product, and obtains an assembly sequence by reversing it. The extraction of some parts and/or subassemblies is performed, based on probabilistic tree transformation. The authors present a calculation example by using a software tool integrated with a CAD system