The Tohoku-Shinkansen line was constructed more than 30 years ago, and the electrical equipment was replaced in the last decade. At the time, however, the grounding systems of the substation were not replaced, because it was assumed that the grounding system had not deteriorated. In this study, we confirm the influence of stray current on the grounding system of the Tohoku-Shinkansen line in certrain ways. The philosophy of a grounding system for the electric railway of Japan is different from that of the international standard. The influence of stray current caused by the D.C. railway on the grounding system of the traction power supply system is confirmed by 30 years' experience of the Tohoku-Shinkansen Line and evaluated quantitatively based on the measured data. Such results are valuable to prove the reliability of Japanese style grounding system and will be instructive to other Asian countries where railways are emerging in the future.
EMC compliance tests for demonstrating no interference to railway signaling systems are becoming more important in manufacturing railway traction inverters. This paper proposes a pre-test for radiation from traction inverter-motor systems. First, the paper describes a simple calculation model of magnetic coupling between motor cables and antenna coils of balises. Next, the paper shows the results of experimental validation tests, which indicate the usefulness of the model. The validation tests are performed on combined-tests and at completed vehicles. Lastly, the paper shows the result of applying the proposed pre-test to an actual DC railcar.
Real-time pricing is one of the primary features of demand response schemes for the future smart grids. From the demand side's point of view, coordination of load management conforming to the rapid power price changes is necessary. This study attempts to optimize a number of multi-unit-type air-conditioning facilities installed in an office building by using a complex evaluation function, which consists of power cost, room temperature comfort terms with priority, and total power consumption. Since an actual experiment lacks reproducibility, simulation experiments with different electricity pricing patterns are carried out. An original air-conditioner emulating model is developed and used to conduct the simulation experiments.
In recent years, systems driven by an independent power source, such as industrial robots and mobile robots have become widely used. The complexity of the wiring is one of the problems in downsizing these systems. For these systems, a power packet dispatching system that transfers electric power with information was proposed. An instantaneous clock synchronization control, which realizes synchronization between systems with 5MHz based power packet dispatching systems is proposed and verified experimentally. In addition, an instantaneous clock synchronization control with multi-hop operation of a power packet dispatching system was verified.
This paper considers the improvement of the demagnetization resistance of concentrated winding IPMSMs under high temperature environments by arranging magnets with different magnetic field orientations. The obliquely oriented magnetized magnets to which Halbach array is applied are arranged on the end face of the rotor, thus improving both the magnetic flux density and demagnetization resistance.
This paper proposes a wireless power transfer system using a series compensator GCSC (Gate Controlled Series Capacitor) as a primary side capacitor. The GCSC is a circuit module that functions as a series variable capacitor by controlling semiconductor switches. The advantage of applying the GCSC to the primary side capacitor is that it provides controllability of the output power factor for a high frequency inverter. Therefore, optimum operation of the high frequency inverter can be achieved irrespective of the coil parameters by controlling the output power factor. Experimental results with a 1kW laboratory prototype confirmed that the proposed system can achieve optimum operation and high efficiencies of the high frequency inverter.
We propose Star-Light Converter that overcomes the weak points of MMC for BTB. Total quantity of capacitors, cell numbers of the Star-Light Converter, and DC currents are almost half those of MMC. The Star-Light Converter has a structure in which cascaded converters are connected between a pair of three-phase converters. We expect Star-Light Converters will be utilized not only in extremely high power applications, but also in low power applications.
This paper proposes a new dynamic mathematical model for double independent three-phase winding permanent-magnet synchronous motors (PMSMs) with iron loss. The proposed model is constructed in the general reference frame, and consists of three consistent basic equations, namely circuit equation, torque evolution equation, and energy transmission equation. In addition to the mathematical model, this paper proposes two new vector simulators for the PMSMs. They are constructed in the general reference frame, and can be quickly reduced to the stator or rotor reference frame. The proposed mathematical model and vector simulator are inevitable and useful for characteristic analyses, drive system developments, etc., for the PMSMs driven in the high-speed region, where iron loss is the dominant factor of total losses.
This paper analyzes the electromagnetic performance of flux-modulating synchronous motors (FMSMs) when the rotor design or motor topology is changed. The following inferences can be made from the results of the finite element analysis. 1) By setting an offset on the salient-pole rotor, it is possible to suppress the harmonics in the back-EMF waveform and reduce the cogging torque and torque pulsation. 2) Even if the rotor design is changed from the salient-pole type to the flux-barrier type or segment type, their torque densities are almost the same. 3) In the outer-rotor configuration, a high torque can be obtained by effectively utilizing the inner space as compared with the inner-rotor configuration. In addition, the outer-rotor configuration makes it easy to reduce the losses and improve the efficiency while obtaining nearly the same torque density as that of the partitioned-stator configuration.
This paper presents the results of the experimental performance verification of a fault-tolerant vector control method for PMSMs with a low resolution Hall-effect sensor, which was recently proposed by one of the authors but without experimental verification of its usefulness.
Spaces Intelligent Lab. (Hashimoto Lab.) conducts researches on human support technologies based on the space intelligence. The space intelligence is a process of creating highly intelligent space by observing the position and information of human beings and objects in a space, understanding and interacting with them. This laboratory engages in researches on human support systems pursuing a wide range of application fields about the space intelligence.