Daisuke Hiramatsu

A Study on Rotor Surface Losses in Small-to-Medium Cylindrical Synchronous Machine

This paper presents a new method for estimation of rotor surface losses in small-to-medium capacity synchronous machines. In this study, the authors have proposed a method for estimating the slot ripple losses induced on the rotor surface. Also, we compared the damper systems using the finite-element method and verified the results by the measured data.

Analytical study on generator load rejection characteristic using advanced equivalent circuit

This paper describes the analytical study on generator load rejection characteristic using the advanced equivalent circuit model. The authors have studied the synchronous machine equivalent circuit model and transient phenomena, by simulation with the electromagnetic transients program (ATP-EMTP), and compared the results with the experimental data

Effects of field mutual leakage reactance in rotor circuit of synchronous generator on the transient and dynamic behavior

This paper describes the effects of field mutual leakage reactance in rotor circuit (Canay reactance) on analysis of generator transient and dynamic behavior. The authors derived a detailed equivalent circuit model for generator, and analyzed sudden short circuit out-of-phase synchronization load rejection and sudden load application phenomena of the generator by simulations using the electromagnetic transients program (ATP-EMTP). Then, they compared the obtained results with the experimental data to verify the validity of the proposed equivalent circuit. In addition to these analyses, the influence of field mutual leakage reactance on analysis of power system dynamic stability was investigated.

Effect of reactance saturation on transient and stability for cylindrical synchronous machine

This paper presents the influence of reactance saturation in transient and stability phenomena for cylindrical synchronous machine. For this purpose the authors have examined various equivalent circuit models using electromagnetic transients program (EMTP-ATP).

A study on quadrature equivalent circuit model in large synchronous machine

This paper describes a study on equivalent circuit model in a large synchronous machine. In this study, the authors studied the quadrature axis transient reactance xpsilaq, not only the influence of the operational impedance , but also the difference of transient and dynamic characteristics using finite element method (FEM) and EMTP.

Brush Sliding Contact Voltage Deviation Analysis Based on the Evaluation of Displacement Excited Vibration caused by Collector Ring Profile Distortion -for Turbine Generators & Traction Motors-

When commutator profile distortion in DC motors or collector ring profile distortion in AC generators or motors are caused, stabilities and reliabilities of sliding contact phenomena will be lost, causing mechanical contact instabilities and contact voltage instabilities. In this paper, how to estimate the mechanical vibration out of the ring profile distortion and how to estimate contact voltage deviation out of the mechanical vibration, are introduced.

Estimation of field mutual leakage reactance in synchronous machine by line-to-line sudden short circuit test

This paper describes the effect of field mutual leakage reactance in rotor circuit (Canay reactance) on analysis of small or medium capacity generator transient and dynamic behavior .The authors proposed the decision method of field mutual leakage reactance, and analyzed sudden short circuit and the power system dynamic stability characteristics affected by the rotor mutual leakage reactance

A study on rotor surface lossesa in small-to-medium cylindrical synchronous machine

Summary form only given. This paper presents a new method for estimation of rotor surface losses in small to medium capacity synchronous machines. In this study, the authors have proposed a method for estimating the slot ripple losses induced on the rotor surface. Also, we compared the damper systems using the Finite Element Method (FEM) and verified the results by the measured data.

Novel interspersed windings to reduce space flux harmonics caused by fractional-slot of synchronous machine

Fractional-slot windings is widely used in synchronous machine due to give us more flexibility on selection of the number of slot at design stage. It is also known that fractional-slot windings produces additional harmonics compare to integral-slot windings. These harmonics may cause increasing of stray losses and stator core vibration This paper describes the result of space flux harmonics caused by fractional-slot windings and propose novel interspersed windings that reduces the even order and/or fractional number space flux harmonic components. The advantage of proposed winding was confirmed by using numerical analysis and experiment using model winding machine.

Study of saturation characteristic of equivalent circuits for cylindrical synchronous machine

The authors have studied the saturation characteristic of equivalent circuit of cylindrical synchronous machine. Using the measured data, the authors have studied the effect on the saturation characteristic of equivalent circuits by the finite element method (FEM) and the electromagnetic transients program (ATP-EMTP).