ADAPTIVE HYSTERESIS CURRENT VECTOR CONTROL OF SYNCHRONOUS SERVO DRIVES WITH DIFFERENT TOLERANCE AREAS

Control methods of hysteresis current vector control of permanent magnet synchronous servo drive fed by voltage source inverter are examined. Detailed description of the control methods in stationary reference frame with circle, square and hexagon shape tolerance area using adaptive solutions is presented. The theoretical considerations are supported by simulation results

Direct flux and current vector control for induction motor drives using model predictive control theory

The study presents the direct flux and current vector control of an induction motor (IM) drive, which is a relatively newer and promising control strategy, through the use of model predictive control (MPC) techniques. The results highlight that the fast flux control nature of direct flux control strategy is further enhanced by MPC. Predictive control is applied in two of its variants, namely the finite control set and modulated MPC, and the advantages and limitations of the two are underlined. This work also highlights, through experimental results, the importance of prioritising the flux part of the cost function which is particularly significant in the case of an IM drive. The performance of the MPC-based approach is compared with the proportional-integral controller, which also prioritises the flux control loop, under various operating regions of the drive such as in the flux-weakening regime. Simulations show the performance expected with different control strategies which is then verified through experiments

Identification of sensitive R-L parameters of a Multi-phase drive by a vector control

This paper focuses on an experimental method to determine the electric parameters of a seven-phase low-voltage multiphase drive. The drive is a belt driven starter-alternator for powerful cars with Hybrid Electrical Vehicles (HEV) functions. The resistive and inductive parameters are necessary to obtain the six characteristic time constants of the control modeling. Classical direct measurements lead to imprecise results because of very low values for the windings electric resistance (a few mΩ) and inductance (a few μH). Effects of the imprecision on the measurements are all the more important that time constants are obtained by a ratio of cyclic inductances by resistance, with cyclic inductances being a linear combination of seven measured inductances. The methodology for identification detailed in this paper is based on a stator current vector control, in a multi-reference frame. This methodology allows us to get directly these time constants. Numerous measurements allow the robustness of the method to be evaluatedThis work was supported by the French car supplier Valeoand the regional council of France Region-Nord-Pas-De-Calais

Contained semi-field environments for ecological studies on transgenic African malaria vectors: benefits and constraints

New interventions are needed to reduce the burden of vector-borne diseases like malaria and dengué, which are among the most serious and prevalent infectious diseases worldwide. The release of genetically modified (GM) mosquitoes may offer an alternative strategy to do so while circumventing the pitfalls of current vector control methods. Current methodologies are stalling because of drug resistance, absence of vaccines and inadequate mosquito control techniques. GM mosquitoes have been developed that are resistant to pathogen infection and transmission, but the public-health and environmental consequences of releasing such insects are unclear, mainly because of a lack of knowledge of the ecology and population biology of mosquitoes. This book is the reflection of a workshop, held in June 2002, that addressed these issues. Experts on mosquito ecology met for the first time to discuss the current knowledge of mosquito ecology with respect to GM-insect technology. Emphasis of the workshop was on evaluating how human health and natural ecosystems, including target wild-mosquito populations, will respond to the invasion of GM vectors. This volume will stimulate discussion by clearly showing the importance of vector ecology for prevention of vector-borne disease

Vector Sliding Mode Control of Sinusoidal-Field Synchronous Servo Drive

Permanent magnet synchronous servo drive with sinusoidal field is examined. The proposed control method is the sliding mode control, implementing the speed control, the current vector control, limitations and field weakening. The necessary sliding errors are derived. Different evaluation criteria are investigated by simulation and a new one is proposed. The combined vector sliding mode control, where the intervention depends on the magnitude of the sliding errors, is better than the traditional vector bang-bang control. The robustness of the bang-bang control is retained, the switching number and the steady state chattering are decreased

How much vector control is needed to achieve malaria elimination?

Roll Back Malaria's ambitious goals for global malaria reduction by 2015 represent a dilemma for National Malaria Control Programs (NMCPs) that are still far from malaria elimination. Current vector control efforts by NMCPs generally fall short of their potential, leaving many NMCPs wondering how much vector control it will take to achieve malaria elimination. We believe the answer is detailed in the relationships between the entomological inoculation rate (EIR) and four epidemiological measures of malaria in humans. To achieve adequate vector control, NMCPs must evaluate EIRs to identify problematic foci of transmission and reduce annual EIRs to less than one infectious bite per person

Geographic Coincidence of Increased Malaria Transmission Hazard and Vulnerability Occurring at the Periphery of two Tanzanian Villages.

The goal of malaria elimination necessitates an improved understanding of any fine-scale geographic variations in transmission risk so that complementary vector control tools can be integrated into current vector control programmes as supplementary measures that are spatially targeted to maximize impact upon residual transmission. This study examines the distribution of host-seeking malaria vectors at households within two villages in rural Tanzania. Host-seeking mosquitoes were sampled from 72 randomly selected households in two villages on a monthly basis throughout 2008 using CDC light-traps placed beside occupied nets. Spatial autocorrelation in the dataset was examined using the Moran's I statistic and the location of any clusters was identified using the Getis-Ord Gi* statistic. Statistical associations between the household characteristics and clusters of mosquitoes were assessed using a generalized linear model for each species. For both Anopheles gambiae sensu lato and Anopheles funestus, the density of host-seeking females was spatially autocorrelated, or clustered. For both species, houses with low densities were clustered in the semi-urban village centre while houses with high densities were clustered in the periphery of the villages. Clusters of houses with low or high densities of An. gambiae s.l. were influenced by the number of residents in nearby houses. The occurrence of high-density clusters of An. gambiae s.l. was associated with lower elevations while An. funestus was also associated with higher elevations. Distance from the village centre was also positively correlated with the number of household occupants and having houses constructed with open eaves. The results of the current study highlight that complementary vector control tools could be most effectively targeted to the periphery of villages where the households potentially have a higher hazard (mosquito densities) and vulnerability (open eaves and larger households) to malaria infection

Are housing improvements an effective supplemental vector control strategy to reduce malaria transmission? A Systematic Review

Malaria, a preventable disease caused by a mosquito-transmitted parasitic infection, continues to be a prominent public health problem today. Progress has been made in the last decade demonstrated by malaria mortality reductions primarily attributed to current vector control strategies. However, the continuing threat of resistance, both resistance of mosquitoes to insecticides and parasites to antimalarial medicines, requires the development of new and improved strategies to supplement those already in place. Housing improvements such as screening doors and windows, closing eaves, patching cracks in walls, and installing ceilings are one such intervention that help stop contact between malaria vectors and humans, and therefore, help stop malaria transmission. Historically considered successful in helping fight malaria, housing improvements are being looked to again today