Development of Three-Dimensional Neoclassical Transport Simulation Code with High Performace Fortran on a Vector-Parallel Computer

A neoclassical transport simulation code (FORTEC-3D) applicable to threedimensional configurations has been developed using High Performance Fortran (HPF). Adoption of computing techniques for parallelization and a hybrid simulation model to the delta f Monte-Carlo method transport simulation, including non-local transport effects in three-dimensional configurations, makes it possible to simulate the dynamism of global, non-local transport phenomena with a self-consistent radial electric field within a reasonable computation time. In this paper, development of the transport code using HPF is reported. Optimization techniques in order to achieve both high vectorization and parallelization efficiency, adoption of a parallel random number generator, and also benchmark results, are shown

Ultra-low-frequency self-oscillation of photocurrent in InxGa1–xAs/Al0.15Ga0.85As multiple-quantum-well p–i–n diodes

We report an observation of ultra-low-frequency self-oscillation of photocurrent in InxGa1–xAs/Al0.15Ga0.85As multiple-quantum-well p–i–n diodes. The photocurrent intensity shows self-oscillations with a characteristic frequency of ~0.1 Hz at low temperatures under reverse bias voltages. The photocurrent self-oscillation depends on applied bias voltage, temperature, illumination power, and indium content of quantum-well layers. These dependences indicate that the photocurrent self-oscillation is attributed to photogenerated carriers trapped in localized centers within InxGa1–xAs quantum-well regions

Non-local Simulation of the Formation of Neoclassical Ambipolar Electric Field in Non-axisymmetric Configurations

Neoclassical transport simulation code (FORTEC-3D) applicable to non-axisymmetric configurations is developed. Adoption of a new hybrid simulation model, in which ion transport is solved by using the delta f Monte-Carlo method including the finite-orbit-width effects while electron transport is solved by a reduced ripple-averaged kinetic equation, makes it possible to simulate the dynamism of non-local transport phenomena with self-consistently developing radial electric field within a allowable computation time. Time evolution of radial electric field in LHD plasma is simulated in the full volume of confinement region, and the finite-orbit-width effect of neoclassical transport is found to make the negative ambipolar electric field more larger than the prediction by a local transport theory

LUT-less Sensorless Control of Synchronous Reluctance Machines using the Locus of Incremental Saliency Ratio Tracking (LIST)

This paper deals with the LUT-less sensorless control of synchronous reluctance (SyR) machines at zero and low speed, where LUT-less stands for avoiding the use of flux-map look-up tables (LUTs) or other pre-determined machine parameters. The new signal-injection based control scheme called the Locus of Incremental Saliency ratio Tracking (LIST) is presented, where a pulsating high-frequency voltage component is used for position tracking and a second rotating signal-injection is dedicated to on-line estimating the incremental saliency ratio. A trajectory of constant incremental saliency ratio is used for torque regulation, resulting in stable control at all operating conditions, including overload. This despite the effect of cross-saturation, which is known to introduce position error and harm the control stability progressively with the load. The proposed scheme is validated experimentally on a 1.1 kW SyR machine test-bench. Alternative LUT-less torque control laws are investigated, and their stability limits put in evidence using convergence analysis and experiments

Hospital preparedness for foreign patients : A postal survey of 97 public hospitals in Japan

研究報