Nobuo Terauchi

Theoretical analysis of cancellation of DC-link current harmonics in the inverter-controlled DC electric railcar

This paper presents the theoretical studies on the DC-link current harmonics in the inverter-controlled DC electric railcar. First, we derive the mathematical expression of the harmonics. And comparison among a theoretical result, a numerical simulation result, and an experimental result is also presented for verification of the proposed theoretical analysis. Then this paper examines the harmonic cancellation effect of the phase shift operation by the derived mathematical expression.

Theoretical analysis of return current harmonics in the inverter-controlled DC electric railcar

The harmonics of the return current may interfere with the signaling current along with the rails. In order to investigate the index of the compatibility with the signaling current, the theoretical investigation of the return current harmonics is preferable rather than expensive and time consuming experimental study. In this paper, we present the theoretical studies of the return current harmonics with the asynchronous type two-step PWM in the inverter-controlled DC electric railcar, aiming at contributing future work to improve the compatibility with the signaling current. We analyze the return current harmonics by the following two methods. The first one is to derive theoretically the return current harmonics with the motor current harmonics approximation. The second one is to simulate numerically a traction circuit including a inverter and a motor, in order to verify theoretically derived return current. Comparing the both results, we concluded the theoretical return current is enough accurate to be utilized for the future improvement of inverter harmonics current.

Loss analysis of permanent-magnet synchronous motor using three-dimensional finite-element method with homogenization method

This paper describes an iron-loss analysis of permanent-magnet synchronous motor (PMSM) taking into account lamination of iron core by a finite-element method (FEM) with a homogenization method. The detailed modeling of the laminated structure by the FEM with gap elements and double nodes requires a huge number of elements, which results in the limitation of the problem size. In order to reduce the computational costs, we apply the homogenization method to iron-loss analyses of a skewed interior PMSM and a surface permanent-magnet motor with overhanging magnet. For the clarification of the effectiveness, the homogenization method is compared with the detailed modeling from the viewpoints of computational costs and accuracy. As a consequence, it is verified that the homogenization method can analyze magnetic fields in a laminated iron core of a practical electric machine within acceptable computational costs.

Narrow and Standard Gauge Lines Operations

This article illustrates a novel design of traction power converter and the specified control strategy of traction equipment of the GCT. We also introduce the test results to verify the basic function of the propulsion system and refer to the operating results in the gauge changing section to verify the control strategy.

Development of a Gas Turbine Generator On-Board Electric Power Source for MAGLEV Trains

We have been jointly developing an on-board electric power source for MAGLEV trains by applying a 30kW generator for gas turbine hybrid passenger cars.Operating the generator on a test model apparatus simulating the generator installed in a MAGLEV train, we investigated its electrical and mechanical characteristics with the location close to superconducting coils. The effects of magnetic field on the generator’s characteristics are investigated and described in this paper.MAGLEV trains require about a 50kW on-board power supply per car. At present, we are designing a 50kW gas turbine generator on the basis of the 30kW gas turbine generator.Copyright