Electrical drive for compressor on turbocharged engine

Turbochargers are usually driven by turbine powered by exhausted gases. This conception is relatively simple but the compressor is not able to overcharge the compressed air or fuel-air mixture into the cylinder in the total revolution range and power regimes. Next disadvantage of turbine driven compressor is the low dynamic response of the turbine and compressor at quick fuel supply increase. There are two possible solutions. First - the “electrocharger”, that is the fully electric driven compressor can be used. Second - the hybrid driven charger is possible. Research of supercharging systems is one of activities of Josef Božek Research Centre of Engine and Automotive Technology on Faculties of Mechanical and Electrical Engineering at Czech Technical University in Prague. Part of this activity is research of electrical drive for the hybrid supercharging system especially from control point of view. Electric synchronous motor with permanent magnets was chosen as electric driving machine. Its robustness, high torque overload features, its small size and mass, high dynamical features and feasible high revolutions are promising for this implementation. Paper deals with torque control of high speed permanent magnet synchronous motor for driving compressor of supercharged combustion engines. Control structure which includes regimes with both full magnetic flux and flux weakening is described. Paper describes the research working place and presents test results achieved on 40 000 rev/min synchronous permanent magnet motor

Development of the diagnostic tools for the COMPASS-U tokamak and plans for the first plasma

The COMPASS-U tokamak (R = 0.894 m, a = 0.27 m, Bt = 5 T, Ip = 2 MA) is a new medium-size device with fully metallic plasma facing components, currently under construction at the Institute of Plasma Physics of the Czech Academy of Sciences in Prague. It features a unique combination of parameters, such as a high temperature of the tokamak walls up to 500 ◦C allowing a high recycling regime, a high magnetic field connected with a high plasma density above 1020 m -3 and with a high heat flux (perpendicular to divertor targets) density at the outer strikepoint up to 90 MW/m2 in attached conditions. These parameters of the device pose strict constraints and requirements on the design of individual diagnostic systems. Strategy and present status of the development of the diagnostic systems for COMPASS-U are provided. Plans for a diagnostic set for the first plasma are reviewed. The review of the diagnostics systems involves the high-temperature compatible slow (up to 20 kHz) and fast (up to several MHz) inductive and non-inductive magnetic sensors (including Thick Printed Copper coils and Hall sensors), the sub-millimetre interferometer with an unambiguous channel, Electron Cyclotron Emission, the interlock and overview cameras, high resolution Thomson scattering, radiation diagnostics (neutron diagnostics, soft and hard X-ray diagnostics, bolometers, impurity monitors, effective ion charge), probe diagnostics (including rail probes) and manipulators

Overview of the COMPASS results

COMPASS addressed several physical processes that may explain the behaviour of important phenomena. This paper presents results related to the main fields of COMPASS research obtained in the recent two years, including studies of turbulence, L–H transition, plasma material interaction, runaway electron, and disruption physics: • Tomographic reconstruction of the edge/SOL turbulence observed by a fast visible camera allowed to visualize turbulent structures without perturbing the plasma. • Dependence of the power threshold on the X-point height was studied and related role of radial electric field in the edge/SOL plasma was identified. • The effect of high-field-side error fields on the L–H transition was investigated in order to assess the influence of the central solenoid misalignment and the possibility to compensate these error fields by low-field-side coils. • Results of fast measurements of electron temperature during ELMs show the ELM peak values at the divertor are around 80% of the initial temperature at the pedestal. • Liquid metals were used for the first time as plasma facing material in ELMy H-mode in the tokamak divertor. Good power handling capability was observed for heat fluxes up to 12 MW m−2 and no direct droplet ejection was observed. • Partial detachment regime was achieved by impurity seeding in the divertor. The evolution of the heat flux footprint at the outer target was studied. • Runaway electrons were studied using new unique systems—impact calorimetry, carbon pellet injection technique, wide variety of magnetic perturbations. Radial feedback control was imposed on the beam. • Forces during plasma disruptions were monitored by a number of new diagnostics for vacuum vessel (VV) motion in order to contribute to the scaling laws of sideways disruption forces for ITER. • Current flows towards the divertor tiles, incl. possible short-circuiting through PFCs, were investigated during the VDE experiments. The results support ATEC model and improve understanding of disruption loads