A dSPACE-based implementation of ANFIS and predictive current control for a single phase boost power factor corrector.

This paper presents an innovative control scheme designed to significantly enhance the power factor of AC/DC boost rectifiers by integrating an adaptive neuro-fuzzy inference system (ANFIS) with predictive current control. The innovative control strategy addresses key challenges in power quality and energy efficiency, demonstrating exceptional performance under diverse operating conditions. Through rigorous simulation, the proposed system achieves precise input current shaping, resulting in a remarkably low total harmonic distortion (THD) of 3.5%, which is well below the IEEE-519 standard threshold of 5%. Moreover, the power factor reaches an outstanding 0.990, indicating highly efficient energy utilization and near-unity power factor operation. To validate the theoretical findings, a 500 W laboratory prototype was implemented using the dSPACE ds1104 digital controller. Steady-state analysis reveals sinusoidal input currents with minimal THD and a power factor approaching unity, thereby enhancing grid stability and energy efficiency. Transient response tests further demonstrate the system's robustness against load and voltage fluctuations, maintaining output voltage stability within an 18 V overshoot and a 20 V undershoot during load changes, and achieving rapid response times as low as 0.2 s. Comparative evaluations against conventional methods underscore the superiority of the proposed control strategy in terms of both performance and implementation simplicity. By harnessing the strengths of ANFIS-based voltage regulation and predictive current control, this scheme offers a robust solution to power quality issues in AC/DC boost rectifiers, promising substantial energy savings and improved grid stability. The results affirm the potential of the proposed system to set new benchmarks in power factor correction technology.

Factors associated with global longitudinal strain decline in hypertensive patients with normal left ventricular ejection fraction.

Background Early detection of risk factors for left ventricular (LV) dysfunction may be useful in patients with high blood pressure (HBP). Methods Patient from an outpatient HBP clinic underwent a two-dimensional Doppler-coupled echocardiography with determination of LV global longitudinal strain (GLS) by speckle-tracking. Results Among 200 patients (mean age 61.7 ± 9.7 years), 155 were overweight, 93 had diabetes, 83 had dyslipidemia, and 109 had uncontrolled HBP. LV hypertrophy (LVH) was found in 136 patients (68%), including concentric ( n = 106) and eccentric ( n = 30) LVH. Diastolic dysfunction patterns were observed in 178 patients (89%), and increased filling pressures were observed in 37 patients (18.5%). GLS ranged from -25% to -11.6% (mean -16.9 ± 3.2%). Low GLS values (>-17%) were found in 91 patients (45.5%), 68 with and 23 without LVH. In univariate analysis, a reduced GLS was associated with HBP lasting for >10 years (odds ratio (OR) = 3.51, 95% confidence interval (CI) 1.73-7.09; p = 0.002), uncontrolled HBP (OR = 3.55, 95% CI 1.96-6.43; p < 0.0001), overweight (OR = 2.01, 95% CI 0.93-4.31; p = 0.0028), diabetes (OR = 2.21, 95% CI 1.25-3.90; p = 0.006), dyslipidemia (OR = 2.16, 95% CI 1.22-3.84; p = 0.008), renal failure (OR = 4.27, 95% CI 1.80-10.10; p = 0.001), an increased Cornell index (OR = 3.70, 95% CI 1.98-6.90; p < 0.0001), concentric LVH (OR = 9.26, 95% CI 2.62-32.73; p = 0.001), remodeling (OR = 8.51, 95% CI 2.18-33.23; p = 0.002), and filling pressures (OR = 7.1, 95% CI 2.9-17.3; p < 0.0001). In multivariable analysis, duration of HBP ( p = 0.038), uncontrolled BP ( p = 0.006), diabetes ( p = 0.023), LVH ( p = 0.001), and increased filling pressures ( p = 0.003) remained associated with GLS decline. Conclusion Early impairment of LV function, detected by a reduced GLS, is associated with long-lasting, uncontrolled HBP, overweight, related metabolic changes, and is more pronounced in patients with LVH.

Assessment for Pulmonary Artery Hypertension Using Clinical and Echocardiographic Criteria in Patients With Systemic Sclerosis.

BACKGROUND: Prognosis of systemic sclerosis (SSc) is affected by pulmonary artery hypertension (PAH). METHODS: Among 202 patients (mean age: 46.1 ± 13.3 years; 177 women) with SSc, those with a tricuspid regurgitation (TR) jet maximal velocity at 2D-echocardiography (2DE) < 2.8m/second were not considered at high risk for PAH, whereas those with a TR velocity >3m/second or between 2.8 and 3m/second and associated with dyspnea were. RESULTS: Among 22 patients at risk, 15 (mean age: 50.4 ± 14.3 years) had definite precapillary PAH on right heart catheterization (RHC). The delay period between recognitions of SSc and PAH was 12.9 ± 5.2 years. Dyspnea was present in all 15 patients, 11 (73.3%) being in the New York Heart Association class III or IV. The 2DE showed normal left ventricular geometrics and function (n = 15), enlargement of the right-sided cardiac chambers (n = 12), increased pulmonary arterial resistances with a TR velocity to pulmonary time-velocity integral ratio of > 0.2 (n = 15) and impaired right ventricle function (n = 15). RHC showed severe PAH in all 15 patients (mean pulmonary artery pressure: 48 ± 17mmHg and mean right atrial pressure: 11.8 ± 4.4mmHg) and a reduced cardiac index (2.2L/m²). There was no statistical difference between patients with and without PAH regarding age, sex ratio, duration from onset of disease, diffuse or cutaneous limited type of SSc, Rodnan severity score and presence of digital ulcerations or autoantibodies. Telangiectasia (P = 0.01) and New York Heart Association class III or IV heart failure (P = 0.001) were more frequent in patients with PAH. CONCLUSION: A combined clinical and Doppler-coupled 2DE screening of PAH risk in patients with SSc is useful to select those who can undergo RHC.