Masahiko Ibamoto

GTO Inverter for AC Traction Drives

A 600-kVA capacity GTO inverter for traction drives has been developed using 2500-V/1000-A gate turn-off (GTO) thyristors, and running tests have been carried out. To utilize the advantages of GTO thyristors, circuit inductance of both main loops and snubber loops were minimized in order to decrease overvoltage applied to GTO thyristors after turn-off. Appropriate protection systems for the GTO inverter against commutation failure and overcurrent in traction motors were developed. Running tests for an electric car driven by the GTO inverter showed good control characteristics.

Improvement of fuel consumption for a vehicle with an automatic transmission using driven power control with a powertrain model

Abstract A total control system using a powertrain model is investigated for an automotive automatic transmission. The system provides e efficient control for both the engine and transmission which leads to better fuel consumption and acceleration feeling by optimizing shift timing and throttle valve opening. The new driven power control method using a total control system is described. A test vehicle equipped with an electronically controlled throttle valve is developed and the effectiveness of the proposed control method is verified.

Gradient Index Polymer Optical Waveguide Patterned by Ultraviolet Irradiation

A new fabricating technique which is capable of easy pattern formation in gradient index polymer optical waveguides is proposed. Waveguides are obtained by diffusion and fixing of monomers with low refractive indices into a gel patterned by ultraviolet irradiation. The gradient index profiles can be selectively formed in the irradiated parts due to the difference in diffusion rate of monomers between regions in the same substrate. Waveguide optical properties are also demonstrated.

Selective formation of gradient-index profiles inside a planar polymer substrate by a lithographic technique

A fabricating technique that is capable of easy pattern formation for gradient-index polymer optical devices is proposed. Monomers with low refractive indices are diffused into a gel that contains barium ion patterned by a lithographic technique, and then the diffusion profile is fixed by thermal polymerization. The gradient-index profiles can be selectively formed in the ultraviolet- (UV-) irradiated regions by utilizing the difference in diffusion rate of monomers between regions in the same substrate. The optical properties and shapes of the gradient-index profiles are determined by the diffusion behavior of the monomers into the UV-irradiated regions. A lens array, consisting of two equivalent gradient-index lenses distributed uniformly in the substrate, and a low-loss Y-branched waveguide are fabricated by this technique, and their optical properties are demonstrated.

High reliability control circuit of pwm inverter for electric car drive

An inverter controlled induction motor driving system for electric car is developed and made a trial run. The gate control circuit of PWM inverter in this system is composed of PLLs or other analog circuits to make it simple. This paper describes the operation of this gate control circuit and results of tests. Good adhesion characteristics are obtained in running tests.

Thyristor chopper control using magnetic pulse width modulator

The thyristor chopper control technique for electric vehicles using a magnetic pulse width modulator is described and the chopper control system for Japans nation-wide Shinkansen [1] Train car is given as an example. The operating mechanism of a newly-developed magnetic pulse width modulator and its functions are analyzed. Using them to the best advantage has made it possible to integrate the principal functions for the chopper control, whereby a high degree of simplification of the control system has been attained. The excellent stability of the modulator to electrical noise signals, unavoidable to electric vehicles, is noteworthy. Applications of the technique to battery-operated locomotives and battery-operated fork-lift trucks are also mentioned.

Off-gate signals controlled thyristor chopper equipment for battery-operated vehicles using magnetic phase shifter

We have made sustained efforts to develop a method of controlling thyristor chopper equipment by utilizing a magnetic phase shifter. These efforts have crystallized in the production of thyristor choppers used for the Japanese National Railway New Trunk Line cars, battery-operated locomotives used for the construction work of the Seikan Undersea Tunnel, and other projects. We have recently attained further success in developing a new method for controlling thyristor choppers, which is suitable for battery-operated vehicles such as fork lifts and electric cars. In contrast to the conventional method which causes the magnetic phase shifter to control the chopper ON-gate signals, this new method causes the magnetic phase shifter to control its OFF-gate signals. As a result, the choppers region of a low conduction ratio, often used during brake control of battery-operated vehicles, can be controlled by the magnetic phase shifter region nearby its saturated region, thus quickening chopper response. In addition to this feature, the new method offers many additional merits.