This paper proposes a novel inverter that can independently control two loads. The inverter has nine switches and is made from combined two three-phase inverters with three common switches. A gate signal for each switch is generated by a novel PWM modulation. An experimental apparatus and a cost become small using this inverter. In this paper, a structure of the inverter is introduced. Then, a novel PWM modulation for the inverter is proposed. Finally, an effectiveness of the inverter is shown by comparing the simulation result with the experimental result.

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In this paper, a power converter in combination of 1200V Si-IGBT and SiC-SBD is investigated for decrease of devise loss in compare with Si-PiN diode. To use device simulation which is based on considering of switching experimental results and static characteristics is employed to estimate device loss. In device simulation, also, we adjust an anode injection efficiency of Si-IGBT to increase switching speed and optimize trade-off relation between on-state voltage and switching loss of Si-IGBT due to minimize total device loss. As the device simulation result, the switching frequency of in combination optimized Si-IGBT and SiC-SBD has approximately three times as high as Si-IGBT with Si-PiN diode. Moreover, in this paper, the limitation of switching frequency by comprehensive total device loss with present heat cooling ability is discussed.

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This paper describes how mechanical stress affects the electrical characteristics of power devices, depending on the surface structure of the device and stress direction. We applied ideal external uni-axial stress to the various power devices, and studied the mechanism by comparing results from experiments and simulations. We found that the stress dependence of the on-state voltage mainly arose from the MOSFET portion of the IGBT. This consideration gives us the important information for designing a power module with higher output density.

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We developed deterioration diagnosis technique for bus Joint in Switchboards. Increase of contact resistance by deterioration of a bus joint causes a temperature rise. However, it is difficult to really measure a temperature rise by a minute change of contact resistance. That is a method to detect a change of contact resistance of a bus joint as a temperature fluctuation. We expect that a serious accident such as a short circuit is prevented beforehand by this technique.

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As one of the high-frequency voltage injection approaches for sensorless drive of salient-pole permanent-magnet synchronous motors, there is the constant-amplitude non-rotational high-frequency voltage injection approach. The conventional analyses about characteristics of the high-frequency current due to the voltage injection are limited to near zero speed. Consequently, the approach was basically restricted to the low speed drive. This paper gives new analyses about characteristics of high-frequency current, which take the rotor speed into account and are valid in wide speed range, in contrast to the conventional analyses. On the basis of the new analyses, this paper proposes a new rotor phase estimation method for the constant-amplitude non-rotational high-frequency voltage injection approach, which is valid for wide speed range. The new analyses and rotor phase estimation method can allow extensive use of the constant-amplitude non-rotational high-frequency voltage injection approach in wide speed range.

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The employment of plastic films has increased rapidly with use in flat-panel displays, secondary cells, and electronic devices, in order to make such devices lighter, thinner, and denser. Conventionally, the X-ray thickness measuring system for plastic films usually employs an X-ray spot beam of 10-20mm in diameter. However, this beam area is too large to measure some films, such as small size film components used in electronic devices. Therefore, it is necessary to improve the resolution ability. In the present study for solving this problem, the authors describe a new measuring system using a slit beam X-ray of 0.4mm to accurately measure the thickness of plastic films. The use of this system can drastically improve the resolution in the measurement of plastic film thickness, resulting in an accuracy of ±2.7% or less, for the sample film by the superposition of a polypropylene tape (PP, thickness: 30μm, width: 1or 20mm) over a PP film (thickness: 30μm).

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The control of conveyance between processes still relies on the engineer's experience. It is difficult to correspond to the change in the conveyance layout due to the expansion and reduction of production and the breakdown of conveyance devices. In this paper, we propose a conveyance control system that can adapt to changes in the conveyance layout and we aim at the improvement of the amount of total conveyance.
First of all, the system is divided into the part where the conveyance layout is made a data base and the part where the conveyance control that uses the congestion index is done. Therefore, it is possible to deal flexibly by changing the data base part without changing the conveyance control part when it is necessary to change the conveyance layout suddenly.
In all the combinations of the conveyance layout and the turning on pattern used as a result of the simulation, the proposed conveyance control method became a great result by the amount of total conveyance.

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This paper proposes a new “quad-sampling” method for single-phase H-bridge converters, which performs voltage and current sampling not only at maximal and minimal points but also at zero crossings of the triangle carrier signal for PWM control. The proposed quad-sampling method makes it possible to increase the sampling frequency four times higher than the triangle carrier frequency, resulting in reduction of the control delay inherent in the digital current controller. This paper theoretically reveals that the quad-sampling method can perform correct sampling and control of the converter current at each sampling point. Theoretical analysis derives characteristics of the proposed quad-sampling method. Moreover, the proposed controller is applied to a single-phase active filter to verify its validity, and experimental results show a good performance in harmonic compensation.

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This paper proposes a novel control method for a direct interface converter for management of the energy flow in either an AC or DC supply. The proposed converter is constructed based on an indirect matrix converter. Therefore a proposed control strategy is based on an indirect control method with a triangular carrier wave. The basic operation of the proposed control method is confirmed by experimental results.
In addition, this paper also proposes a commutation error compensation method of an output voltage error and an input current error for an indirect matrix converter. In the proposed method, the output voltage and input current error by the commutation can be compensated at the same time, because the PWM pulse of each switch is directly compensated. The validity of the proposed method is confirmed by experimental results. Those results prove that the proposed compensation method can decrease total harmonic distortion (THD) of the input and output current.

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This Paper proposes a novel conversion scheme of switching patterns for three-phase to three-phase matrix converters. The conventional virtual indirect conversion method is equivalent to PWM technique via an ordinary PWM rectifier/inverter, offering the advantage that no complicated specialized control is required. On the other hand, 6 of 27 switching patterns cannot be used in this method, because the inputs and outputs are always connected by way of the virtual DC link that is composed of 2 lines. This paper therefore defines the direct space vectors that can express the all 27 switching patterns and utilizes the geometric relationship of direct space vectors so that all switching patterns can be converted from other arbitrary vectors. This conversion scheme also allows the duty factor conversion with simple calculation by utilizing the duties of the virtual indirect conversion approach. In particular, the above-mentioned 6 switching patterns that have been restricted can be fully utilized for reducing output voltage harmonics, switching losses and common-mode voltages. The validity of the proposed conversion method is proven from the experimental results compared with a conventional virtual indirect method.

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This paper presents a new spherical resonant actuator. And the basic construction and the operating principle of the actuator are described. The dynamic characteristics are computed using the combined method of the 3-D FEM and the Runge-Kutta Method to easily couple with the equations of electric circuit and motion. As a result, computed results agree well with the measurement of the prototype. The effectiveness of the computation method for the spherical actuator is also clarified.

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The Hybrid magnetically levitated transportation system has been developed. The magnetic rail is set on the ground, and the carrier with permanent magnets and high-Tc superconductors (HTSC) levitates on the rail. Repulsive force of permanent magnet is introduced to support load weight. Pinning force of the HTSC is used to support weight of the frame of the carrier and to achieve lateral stability of the carrier. In this paper, propulsion system of the conveyance system is studied. Propulsion function is installed on the carrier body. Magnetic gradient is used to get propulsion force. Propulsion force of the system is little. So propulsion rail system is introduced. Air core copper coils are installed on the magnetic rail. Interaction between current of these coils and permanent magnets on the carrier generates propulsion force. Enough propulsion force is given. Influence of the propulsion system on the levitation and guidance system is measured. Stability of levitation and guidance system is enough even when propulsion system is operated.

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This paper introduces a mechanical structure and control technique of a second robot finger as a system integration. The finger has been developed as element of a robot hand which has 20 joints and 16 degrees of freedom in order to express fingerspelling. The first joint of the finger is driven by small DC servo motor and the second and third joints are driven by shape-memory alloy (SMA) wires. The hand system consists of four parts of “hand mechanism”, “drive device”, “control unit” and “man-machine interface”. In order to implement cooperative smooth motions, the control system is designed based on experimental results related to system identification, and the position trajectory refernce is designed considering time delay on the SMA. Finally, we report the simulation and experimental control results to evaluate the presented system.

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The referential ZMP (Zero-Moment Point) trajectory that minimizes the variation of COG (Center of Gravity) velocity in the single support phase of a biped robot is shown. Two advantages of using this ZMP trajectory are discussed. The first advantage is that the variation of COG velocity is gradual. The second advantage is that the biped robot enables the heel-contact motion and the toe-off motion in the single support phase. The trajectory planning based on this ZMP trajectory is proposed. In simulation and experiment, the validity of the proposed method was confirmed.

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This paper proposes a multivariable identification method for a SCARA-type planar two-link robot arm with elastic joints caused by reduction gears, which is treated as a serial two-link two-inertia system. The arm for the experimental verification is equipped with accelerometers that have the two roles described below. The proposed method consists of three steps. The first step is the rigid model parameter estimation by the least-squares method. The second step is the elastic model identification using a multi-input multi-output state space model technique, which enables the nonlinear interaction torques between two links to be decoupled. The torques, calculated using the accelerometer signals and the rigid model parameters, are employed as inputs for decoupling in the multi-input identification. The angular velocities of the links, calculated using the accelerometer signals and the motor encoder signals, are employed as outputs for improving accuracy in the multi-output identification. The decoupling method divides the serial two-link two-inertia system into two one-link two-inertia systems in this step. The third step is the physical parameter estimation of the one-link two-inertia systems. The physical parameters consist of motor inertias, link inertias, joint-friction coefficients and joint-spring coefficients. Furthermore fine tuning of the estimated physical parameters is carried out using closed-loop simulations with the nonlinear least-squares optimization. Experimental results using the two-link arm have shown the accuracy of the proposed identification method.

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In this paper, we investigate losses of interior permanent magnet motors with concentrated windings using the 3-D finite element method considering carrier harmonics of PWM inverters. The calculated results are compared with the measurement to verify the validity of the calculation. The motor with the distributed windings is also calculated to clarify the difference of the main loss factors. The measured and calculated results agree well. It is clarified that the losses generated at the rotor core and magnets especially increase, whereas the harmonic iron losses generated at the stator decrease, in the case of the motor with concentrated windings.

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This paper studies a transfer function from steering angle to camber angle of an electrical bicycle by experiments. The bicycle stabilized by a steering controller is able to run and turn. Experimental results confirm that the transfer function of the bicycle is consistent with a theoretical model.

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