Sensorless Feedback Linearization Direct Torque Control (FBL-DTC) for Induction Motor Drive with Five-Level Cascaded H-Bridge Inverter
2018 IEEE 18TH INTERNATIONAL POWER ELECTRONICS AND MOTION CONTROL CONFERENCE (PEMC)
Authors: Usta, Mehmet Ali; Okumus, Hahi Ibrahim; Kahveci, Hakan; Durak, Elif Selin
Abstract
This paper presents a sensorless feedback linearization direct torque control (FBL-DTC) for an induction motor drive with five-level cascaded H-bridge (CHB) inverter. The control of CHB multilevel inverter is realized by multicarrier based third harmonic injection PWM (THIPWM) technique. The alpha and beta components of reference voltage vector are obtained from the feedback linearization approach that achieves a decoupled torque and flux control. To estimate the rotor speed and the stator resistance simultaneously, an extended Kalman filter (EKF) based observer is developed. An adaptive scheme that uses the estimated states and parameters is established to increase the robustness of feedback linearization control against model and measurement uncertainties. The effectiveness of proposed drive system is tested under some challenging operating conditions and verified by the simulation results.
Photocatalytic oxidation of n-butanol under fluorescent visible light lamp over commercial TiO2 (Hombicat UV100 and Degussa P25)
APPLIED CATALYSIS A-GENERAL
Authors: Kirchnerova, J; Cohen, MLH; Guy, C; Klvana, D
Abstract
Photocatalytic oxidation (PCO) of volatile organic compounds (VOC) over TiO2, exploiting visible light of common fluorescent lamps represents an attractive means of indoor air purification. This work compares activity and its variation with calcination of two commercial TiO2, Hombicat UV100 and Degussa P25, in a complete PCO of n-butanol serving as a convenient representative VOC. The PCO of n-butanol was carried out in a flow through reactor under a relatively long residence time using mostly fluorescent visible (white) light (FWL)-lamp for illumination. Fluorescent black light (UV) (FBL)-lamp was used only for comparison. Under FBL-lamp, 580 ppm n-butanol is completely mineralized over both catalysts. Under FWL-lamp the reaction is considerably slower and Degussa P25 appears more active than Hombicat UV100. For 580 ppm, steady state conversions of less than 95% are attained, but at 145 ppm, a complete mineralization is achieved even over Hombicat UV100. Butanal, propartal and ethanal were identified as the main gaseous intermediate products. In addition, a parallel formation of crotonaldehyde, product of aldolization, was detected. The appearance and concentration of crotonaldehyde depended on PCO conditions, particularly on the characteristics of TiO2. Thermal treatment of TiO2 at >= 623 K has a negative effect on the activity in PCO of both catalysts. Apparently, the calcination causes modification of the surface available active sites that is in part reflected by diminution of specific surface area. The effect of reactor residence time, of inlet concentration and of the relative light intensity on the efficiency of the process was also evaluated. (c) 2004 Elsevier B.V. All rights reserved.