ABSTRACT
This paper presents a new control strategy based on finite-control-set model-predictive control (FCS-MPC) for Neutral-point-clamped (NPC) three-level converters. Containing some advantages like fast dynamic response, easy inclusion of constraints and simple control loop, makes the FCS-MPC method attractive to use as a switching strategy for converters. However, the large amount of required calculations is a problem in the widespread of this method. In this way, to resolve this problem this paper presents a modified method that effectively reduces the computation load compare with conventional FCS-MPC method and at the same time does not affect on control performance. The proposed method can be used for exchanging power between electrical grid and DC resources by providing active and reactive power compensations. Experiments on three-level converter for three Power Factor Correction (PFC), inductive and capacitive compensation modes verify the good and comparable performance. The results have been simulated using MATLAB/SIMULINK software.
ABSTRACT
This paper investigates sensorless indirect field oriented control (IFOC) of SLIM with full-order Luenberger observer. The dynamic equations of SLIM are first elaborated to draw full-order Luenberger observer with some simplifying assumption. The observer gain matrix is derived from conventional procedure so that observer poles are proportional to SLIM poles to ensure the stability of system for wide range of linear speed. The operation of observer is significantly impressed by adaptive scheme. A fuzzy logic control (FLC) is proposed as adaptive scheme to estimate linear speed using speed tuning signal. The parameters of FLC are tuned using an off-line method through chaotic optimization algorithm (COA). The performance of the proposed observer is verified by both numerical simulation and real-time hardware-in-the-loop (HIL) implementation. Moreover, a detailed comparative study among proposed and other speed observers is obtained under different operation conditions.
ABSTRACT
BACKGROUND: The present study compared the effectiveness of Family-Based DOTS (FB-DOTS) versus Professional-Family Mix DOTS (PFM-DOTS) in smear positive tuberculosis (TB) patients. METHODS: This semi-experimental study was performed in Tuberculosis and Lung Diseases Research Center of Tabriz in 2011-2012, among 57 TB patients recruited into either FB-DOTS or PFM-DOTS groups. At the baseline of the study, knowledge of both patients and their supervisors were assessed while at the end point, smear and culture of sputum, quality of life, knowledge and satisfaction of the patients along with the knowledge and satisfaction of their supervisors were assessed. RESULTS: The difference for sputum smear negative (culture) was 16.2 (4.8%) and 7.7(6.9%) for the PFM-DOTS in comparison with FB DOTS by the end of the second and forth months of treatment, respectively. A significant difference was observed between the two groups in relation to knowledge, satisfaction (patients and supervisors) and all four domains of quality of life: physical health (P=0.036), psychological health (P<0.001), social relations (P=0.026) and environmental health (P<0.001). CONCLUSION: The PFM-DOTS treatment strategy in which health experts follow the patients in their homes seems to be among most appropriate strategies in treating TB.
