2006 IEEE International Symposium on Industrial Electronics, 2006
This paper proposes the high frequency (hf) voltage injection technique to DTC drives with the ob... more This paper proposes the high frequency (hf) voltage injection technique to DTC drives with the objective of extending their performance to the low and zero speed region. The simplicity of the original DTC algorithm is not compromised. The hf carrier is introduced by the direct modification of the fundamental voltage vectors. The position signal is then obtained from the direct demodulation of the resulting hf currents. Both simulation and experimental results are shown
This paper deals with the rotor angle estimation for further sensorless field oriented control of... more This paper deals with the rotor angle estimation for further sensorless field oriented control of permanent magnet synchronous machines using voltage matrix converters test vectors. The Angle estimation is based on the machine saliency (difference between Ld and Lq), which is properly tracked by the application of pulse voltage test vectors. For all injection methods to function, some level of
The purpose of the study was to describe the clinical characteristics and outcomes of critically ... more The purpose of the study was to describe the clinical characteristics and outcomes of critically ill patients with 2009 influenza A(H1N1). An observational study of patients with confirmed or probable 2009 influenza A(H1N1) and respiratory failure requiring mechanical ventilation was performed. We studied 96 patients (mean age, 45 [14] years [mean, SD]; 44% female). Shock and acute respiratory distress syndrome were diagnosed during the first 72 hours of admission in 43% and 72% of patients, respectively. Noninvasive positive pressure ventilation was used in 45% of the patients, but failed in 77% of them. Bacterial pneumonia was diagnosed in 33% of cases, 8% during the first week (due to community-acquired microorganisms) and 25% after the first week (due to gram-negative bacilli and resistant gram-positive cocci). Intensive care unit mortality was 50%. Nonsurvivors differed from survivors in the prevalence of cardiovascular, respiratory, and hematologic failure on admission and lat...
The aim of this study is to analyze the reticulocyte parameters (classical and research parameter... more The aim of this study is to analyze the reticulocyte parameters (classical and research parameters) acquired by the Beckman Coulter GEN'S blood counter (GEN'S; Brea, CA, USA) to establish the "reticulocyte profile" characteristics of patients with anemia of chronic disease (ACD). The reticulocyte parameters and profile provided by the GEN'S were studied in 38 anemic patients who fulfilled the diagnostic criteria for the ACD, and the results were compared with those of 38 healthy controls in a multivariate statistical analysis using the Student t-test and the receiver operating characteristics (ROC) curve analysis.Statistically significant (P <.05) differences between the 2 population groups were observed in several of the reticulocyte parameters provided by the GEN'S: mean volume of the reticulocyte population (MRV) (high), percentage of high light scatter reticulocytes HLR% (high), mean volume of the whole sphered red cell…
A pharmacological evaluation of Zuccagnia punctata Cav. (Fabaceae) on the gastrointestinal tract ... more A pharmacological evaluation of Zuccagnia punctata Cav. (Fabaceae) on the gastrointestinal tract was made in rats and mice. 2′ ′ ′ ′ ,4′ ′ ′ ′ -dihydroxychalcone and 2′ ′ ′ ′ ,4′ ′ ′ ′ -dihydroxy-3′ ′ ′ ′ -methoxychalcone were isolated from Zuccagnia punctata . The data reported in the present work indicate that the acetone extract and infusion of Zuccagnia punctata reduced intestinal transit in rats and mice and offered protection against ethanol-induced ulceration in rats. The Z. punctata effect could be due, in part, to the presence of 2′ ′ ′ ′,4′ ′ ′ ′-dihydroxychalcone and 2′ ′ ′ ′,4′ ′ ′ ′-dihydroxy-3′ ′ ′ ′-methoxychalcone in this plant.
The purpose of this investigation was to compare the risk factors, clinical features and outcomes... more The purpose of this investigation was to compare the risk factors, clinical features and outcomes in cancer patients with bacteraemia caused by vancomycin-susceptible Enterococcus faecalis and E. faecium. A retrospective, observational 7-year study was carried out in a 450-bed, acute-care university-affiliated hospital. We performed univariate comparisons between the two groups and then multivariate analysis to identify patient risk factors for E. faecium isolation. Seventy-three patients were included in the analysis: 54 (74.0%) with bacteraemia caused by E. faecalis and 19 (26.0%) by E. faecium. The Simplified Acute Physiological Score (SAPS) value was significantly greater in E. faecium isolates (40.7 vs. 35.2; p=0.009). Diabetes mellitus was more frequently diagnosed in patients with E. faecium bacteraemia (52.6% vs. 24.1%; p=0.021). Prior penicillin exposure was more frequent in patients with E.
2007 IEEE International Symposium on Industrial Electronics, 2007
Page 1. High Frequency injection in a Matrix Converter DTC Drive for sensorless operation of a PM... more Page 1. High Frequency injection in a Matrix Converter DTC Drive for sensorless operation of a PMSM Carlos Ortega Electronics Department Escola Universitaria Salesiana de Sarria Barcelona, Spain Email: [email protected] ...
2008 IEEE Power Electronics Specialists Conference, 2008
This paper deals with the rotor angle estimation for further Sensorless Field Oriented Control of... more This paper deals with the rotor angle estimation for further Sensorless Field Oriented Control of Permanent Magnet Synchronous Machines using voltage Matrix Converters test vectors. The angle estimation is based on the machine saliency (difference between Ld and Lq), which is properly tracked by the application of pulse voltage test vectors. For all injection methods to function, some level of
2008 15th IEEE International Conference on Electronics, Circuits and Systems, 2008
This paper investigates the use of a Current Regulator to control Matrix Converters in Field Orie... more This paper investigates the use of a Current Regulator to control Matrix Converters in Field Oriented Control of Permanent Magnet Synchronous Machines Drives. Most of the Field Oriented Control Schemes are used with the standard Voltage Source Inverters and a feed forward Space Vector Modulator. This paper, however, addresses the use of a four quadrant Matrix Converter Drive with a
2005 European Conference on Power Electronics and Applications, 2005
A new digital current controller with active-null state modulation for voltage source inverter sy... more A new digital current controller with active-null state modulation for voltage source inverter systems (VSI) is presented. The major advantages of the proposed current controller system are: minimisation of the total harmonic distortion (THD) of the output current waveform and maximisation of the time of application of the voltage vectors
Abstract This paper investigates the use of short voltage vectors of Matrix Converters to reduc... more Abstract This paper investigates the use of short voltage vectors of Matrix Converters to reduce the electromagnetic torque ripple which appears when Direct Torque Control technique is used in Induction Motors. Direct Torque Control for Induction Motors using Matrix Converters is ...
2008 IEEE International Symposium on Industrial Electronics, 2008
Page 1. Reducing the Common Mode Voltage in a DTC-PMSM drive using Matrix Converters Carlos Orteg... more Page 1. Reducing the Common Mode Voltage in a DTC-PMSM drive using Matrix Converters Carlos Ortega Electronic Department Escola Universit`aria Salesiana de Sarri`a Barcelona, Spain Email: [email protected] Antoni ...
2007 European Conference on Power Electronics and Applications, 2007
Carlos Ortega1, Antoni Arias 2, Cedric Caruana 3, Maurice Apap3, Josep Balcells2, 1Electronics De... more Carlos Ortega1, Antoni Arias 2, Cedric Caruana 3, Maurice Apap3, Josep Balcells2, 1Electronics Dept. Escola Universitària Salesiana de Sarrià. Barcelona, Spain. 2Electronics Engineering Dept. Universitat Politècnica de Catalunya. Terrassa, Spain. 3 Power Electronics Dept. ...
The work presented in this paper addresses the unwanted windup phenomenon reviewing and comparing... more The work presented in this paper addresses the unwanted windup phenomenon reviewing and comparing different PI anti-windup strategies employed in speed control of electric drives. The tuning process of PI controllers is usually carried out considering the system as linear and therefore disregarding its physical limits such as maximum current and voltage. To safeguard the system's integrity, the PI output is normally limited eventually causing the windup phenomenon characterized by long periods of overshoots which may even result in instability.
2006 12th International Power Electronics and Motion Control Conference, 2006
* Escola Universit'aria Salesiana de Sarri'a. Electronics Dept.... more * Escola Universit'aria Salesiana de Sarri'a. Electronics Dept. Barcelona, Spain ** Universitat Politecnica de Catalunya. Electronics Engineering Dept. Terrassa, Spain. t University of Malta. Power Electronics Dept. Msida, Malta. ... Abstract-The effects on torque ...
2011 7th International Conference-Workshop Compatibility and Power Electronics (CPE), 2011
Abstract This paper deals with the validation of an EMI model to predict electromagnetic interfer... more Abstract This paper deals with the validation of an EMI model to predict electromagnetic interferences (EMI) produced by direct AC/AC matrix converters (MC). The method is based on obtaining a high frequency equivalent circuit, using a combined time and frequency ...
2006 IEEE International Symposium on Industrial Electronics, 2006
This paper proposes the high frequency (hf) voltage injection technique to DTC drives with the ob... more This paper proposes the high frequency (hf) voltage injection technique to DTC drives with the objective of extending their performance to the low and zero speed region. The simplicity of the original DTC algorithm is not compromised. The hf carrier is introduced by the direct modification of the fundamental voltage vectors. The position signal is then obtained from the direct demodulation of the resulting hf currents. Both simulation and experimental results are shown
This paper deals with the rotor angle estimation for further sensorless field oriented control of... more This paper deals with the rotor angle estimation for further sensorless field oriented control of permanent magnet synchronous machines using voltage matrix converters test vectors. The Angle estimation is based on the machine saliency (difference between Ld and Lq), which is properly tracked by the application of pulse voltage test vectors. For all injection methods to function, some level of
The purpose of the study was to describe the clinical characteristics and outcomes of critically ... more The purpose of the study was to describe the clinical characteristics and outcomes of critically ill patients with 2009 influenza A(H1N1). An observational study of patients with confirmed or probable 2009 influenza A(H1N1) and respiratory failure requiring mechanical ventilation was performed. We studied 96 patients (mean age, 45 [14] years [mean, SD]; 44% female). Shock and acute respiratory distress syndrome were diagnosed during the first 72 hours of admission in 43% and 72% of patients, respectively. Noninvasive positive pressure ventilation was used in 45% of the patients, but failed in 77% of them. Bacterial pneumonia was diagnosed in 33% of cases, 8% during the first week (due to community-acquired microorganisms) and 25% after the first week (due to gram-negative bacilli and resistant gram-positive cocci). Intensive care unit mortality was 50%. Nonsurvivors differed from survivors in the prevalence of cardiovascular, respiratory, and hematologic failure on admission and lat...
The aim of this study is to analyze the reticulocyte parameters (classical and research parameter... more The aim of this study is to analyze the reticulocyte parameters (classical and research parameters) acquired by the Beckman Coulter GEN'S blood counter (GEN'S; Brea, CA, USA) to establish the "reticulocyte profile" characteristics of patients with anemia of chronic disease (ACD). The reticulocyte parameters and profile provided by the GEN'S were studied in 38 anemic patients who fulfilled the diagnostic criteria for the ACD, and the results were compared with those of 38 healthy controls in a multivariate statistical analysis using the Student t-test and the receiver operating characteristics (ROC) curve analysis.Statistically significant (P <.05) differences between the 2 population groups were observed in several of the reticulocyte parameters provided by the GEN'S: mean volume of the reticulocyte population (MRV) (high), percentage of high light scatter reticulocytes HLR% (high), mean volume of the whole sphered red cell…
A pharmacological evaluation of Zuccagnia punctata Cav. (Fabaceae) on the gastrointestinal tract ... more A pharmacological evaluation of Zuccagnia punctata Cav. (Fabaceae) on the gastrointestinal tract was made in rats and mice. 2′ ′ ′ ′ ,4′ ′ ′ ′ -dihydroxychalcone and 2′ ′ ′ ′ ,4′ ′ ′ ′ -dihydroxy-3′ ′ ′ ′ -methoxychalcone were isolated from Zuccagnia punctata . The data reported in the present work indicate that the acetone extract and infusion of Zuccagnia punctata reduced intestinal transit in rats and mice and offered protection against ethanol-induced ulceration in rats. The Z. punctata effect could be due, in part, to the presence of 2′ ′ ′ ′,4′ ′ ′ ′-dihydroxychalcone and 2′ ′ ′ ′,4′ ′ ′ ′-dihydroxy-3′ ′ ′ ′-methoxychalcone in this plant.
The purpose of this investigation was to compare the risk factors, clinical features and outcomes... more The purpose of this investigation was to compare the risk factors, clinical features and outcomes in cancer patients with bacteraemia caused by vancomycin-susceptible Enterococcus faecalis and E. faecium. A retrospective, observational 7-year study was carried out in a 450-bed, acute-care university-affiliated hospital. We performed univariate comparisons between the two groups and then multivariate analysis to identify patient risk factors for E. faecium isolation. Seventy-three patients were included in the analysis: 54 (74.0%) with bacteraemia caused by E. faecalis and 19 (26.0%) by E. faecium. The Simplified Acute Physiological Score (SAPS) value was significantly greater in E. faecium isolates (40.7 vs. 35.2; p=0.009). Diabetes mellitus was more frequently diagnosed in patients with E. faecium bacteraemia (52.6% vs. 24.1%; p=0.021). Prior penicillin exposure was more frequent in patients with E.
2007 IEEE International Symposium on Industrial Electronics, 2007
Page 1. High Frequency injection in a Matrix Converter DTC Drive for sensorless operation of a PM... more Page 1. High Frequency injection in a Matrix Converter DTC Drive for sensorless operation of a PMSM Carlos Ortega Electronics Department Escola Universitaria Salesiana de Sarria Barcelona, Spain Email: [email protected] ...
2008 IEEE Power Electronics Specialists Conference, 2008
This paper deals with the rotor angle estimation for further Sensorless Field Oriented Control of... more This paper deals with the rotor angle estimation for further Sensorless Field Oriented Control of Permanent Magnet Synchronous Machines using voltage Matrix Converters test vectors. The angle estimation is based on the machine saliency (difference between Ld and Lq), which is properly tracked by the application of pulse voltage test vectors. For all injection methods to function, some level of
2008 15th IEEE International Conference on Electronics, Circuits and Systems, 2008
This paper investigates the use of a Current Regulator to control Matrix Converters in Field Orie... more This paper investigates the use of a Current Regulator to control Matrix Converters in Field Oriented Control of Permanent Magnet Synchronous Machines Drives. Most of the Field Oriented Control Schemes are used with the standard Voltage Source Inverters and a feed forward Space Vector Modulator. This paper, however, addresses the use of a four quadrant Matrix Converter Drive with a
2005 European Conference on Power Electronics and Applications, 2005
A new digital current controller with active-null state modulation for voltage source inverter sy... more A new digital current controller with active-null state modulation for voltage source inverter systems (VSI) is presented. The major advantages of the proposed current controller system are: minimisation of the total harmonic distortion (THD) of the output current waveform and maximisation of the time of application of the voltage vectors
Abstract This paper investigates the use of short voltage vectors of Matrix Converters to reduc... more Abstract This paper investigates the use of short voltage vectors of Matrix Converters to reduce the electromagnetic torque ripple which appears when Direct Torque Control technique is used in Induction Motors. Direct Torque Control for Induction Motors using Matrix Converters is ...
2008 IEEE International Symposium on Industrial Electronics, 2008
Page 1. Reducing the Common Mode Voltage in a DTC-PMSM drive using Matrix Converters Carlos Orteg... more Page 1. Reducing the Common Mode Voltage in a DTC-PMSM drive using Matrix Converters Carlos Ortega Electronic Department Escola Universit`aria Salesiana de Sarri`a Barcelona, Spain Email: [email protected] Antoni ...
2007 European Conference on Power Electronics and Applications, 2007
Carlos Ortega1, Antoni Arias 2, Cedric Caruana 3, Maurice Apap3, Josep Balcells2, 1Electronics De... more Carlos Ortega1, Antoni Arias 2, Cedric Caruana 3, Maurice Apap3, Josep Balcells2, 1Electronics Dept. Escola Universitària Salesiana de Sarrià. Barcelona, Spain. 2Electronics Engineering Dept. Universitat Politècnica de Catalunya. Terrassa, Spain. 3 Power Electronics Dept. ...
The work presented in this paper addresses the unwanted windup phenomenon reviewing and comparing... more The work presented in this paper addresses the unwanted windup phenomenon reviewing and comparing different PI anti-windup strategies employed in speed control of electric drives. The tuning process of PI controllers is usually carried out considering the system as linear and therefore disregarding its physical limits such as maximum current and voltage. To safeguard the system's integrity, the PI output is normally limited eventually causing the windup phenomenon characterized by long periods of overshoots which may even result in instability.
2006 12th International Power Electronics and Motion Control Conference, 2006
* Escola Universit'aria Salesiana de Sarri'a. Electronics Dept.... more * Escola Universit'aria Salesiana de Sarri'a. Electronics Dept. Barcelona, Spain ** Universitat Politecnica de Catalunya. Electronics Engineering Dept. Terrassa, Spain. t University of Malta. Power Electronics Dept. Msida, Malta. ... Abstract-The effects on torque ...
2011 7th International Conference-Workshop Compatibility and Power Electronics (CPE), 2011
Abstract This paper deals with the validation of an EMI model to predict electromagnetic interfer... more Abstract This paper deals with the validation of an EMI model to predict electromagnetic interferences (EMI) produced by direct AC/AC matrix converters (MC). The method is based on obtaining a high frequency equivalent circuit, using a combined time and frequency ...
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