pSS Controls Research Articles

Improvement of an AC microgrid system’s stability by using a fuzzy logic-based PSS controller

This research article presents the low-frequency oscillation damping control of an AC Microgrid. It is integrated with four distributed generation units in which two DGs are renewable energy source based solar PV and wind energy using DFIG and the other two DGs are conventional synchronous generator-based hydro and diesel generators. There is insufficient generation through renewable-based DG then a diesel generator is employed as an emergency unit to fulfil the requirements and maintain and control the deviation of the frequency of the system. The use of renewable-based DG affected the system's dynamic stability and the characteristics of an integrated microgrid differ from conventional sources of generation. This investigation explores the impression of the deployment of multiple forms of the power oscillation damping (POD) controllers to distributed generation sources of grid forming AC Microgrid. The main various types of POD controllers are conventional lead-lag PSSs, MBPSS-4B, and proposed robust fuzzy logic PSS (FLPSS) controllers are implemented on distributed generation units of AC Microgrid for the elimination of low-frequency oscillation. Low oscillation frequencies between 0.1 and 2 Hz are the focus of this work. The system's damping ratios and stability margins because of MG integration are observed using eigenvalues analysis. The results of the simulation test demonstrate the accomplishment of the robust fuzzy logic PSS controller regarding conventional lead-lag PSSs and the MBPSS-4B controller during circumstances of fault.

Impact and Integration of Electric vehicles on renewable energy based Microgrid: Frequency profile improvement by a-SCA optimized FO-Fuzzy PSS approach

The modelling of an electric vehicle along with its integration and impact over a renewable energy based microgrid topology is well addressed in this manuscript. The frequent charging and discharging of the electric vehicle makes an oscillation over grid frequency. The performance especially frequency of an islanded AC microgrid is also affected seriously under the actions of different uncertainties like load dynamics, wind fluctuation in wind plant, solar intensity variation of PV plant etc. In order to maintain standard frequency, this research work aims to regulate the net power generation of the system in response to total demand. To monitor net generation, this work has intended a fractional order fuzzy power system stabilizer (FO-Fuzzy PSS) control scheme in several dynamic situations. The proposed FO-Fuzzy PSS control scheme acts as most potential candidate to pertain stability in system frequency in above discussed disturbances. The controller gains are tuned optimally with suggesting an advanced- Sine Cosine Algorithm (a-SCA) under different conditions. The performance of the optimal FO- Fuzzy PSS controller is compared over standard fuzzy controller and PID controller in regard to frequency regulation of microgrid system. It is observed that proposed FO-Fuzzy PSS control scheme has the credential to reduce settling time of ΔF1 (area1 microgrid frequency) by 98.60% and 250.82% over fuzzy controller & PID controller correspondingly. Further, the dynamic optimal performance of the proposed a-SCA is compared over original SCA and PSO techniques to justify its superiority.

Coordinated control of multi band PSS (MBPSS) with type 2 fuzzy based SSSC controller design for power system stability improvement

Coordinated control of multi band PSS (MBPSS) with type 2 fuzzy based SSSC controller design for power system stability improvement

Extranodal marginal zone lymphoma clonotypes are detectable prior to eMZL diagnosis in tissue biopsies and peripheral blood of Sjögren's syndrome patients through immunogenetics.

Activated B cells play a key role in the pathogenesis of primary Sjögren's syndrome (pSS) through the production of autoantibodies and the development of ectopic germinal centers in the salivary glands and other affected sites. Around 5-10% of pSS patients develop B-cell lymphoma, usually extranodal marginal zone lymphomas (eMZL) of the mucosa-associated lymphoid tissue (MALT). The aim of the current study is to investigate if the eMZL clonotype is detectable in prediagnostic blood and tissue biopsies of pSS patients. We studied prediagnostic tissue biopsies of three pSS patients diagnosed with eMZL and four pSS controls through immunoglobulin (IG) gene repertoire sequencing. In all three cases, we observed the eMZL clonotype in prediagnostic tissue biopsies. Among controls, we observed transient elevation of clonotypes in two pSS patients. To evaluate if eMZL clonotypes may also be detected in the circulation, we sequenced a peripheral blood mononuclear cell (PBMC) sample drawn at eMZL diagnosis and two years prior to eMZL relapse in two pSS patients. The eMZL clonotype was detected in the peripheral blood prior to diagnosis in both cases. Next, we selected three pSS patients who developed eMZL lymphoma and five additional pSS patients who remained lymphoma-free. We sequenced the IG heavy chain (IGH) gene repertoire in PBMC samples taken a median of three years before eMZL diagnosis. In two out of three eMZL patients, the dominant clonotype in the prediagnostic PBMC samples matched the eMZL clonotype in the diagnostic biopsy. The eMZL clonotypes observed consisted of stereotypic IGHV gene combinations (IGHV1-69/IGHJ4 and IGHV4-59/IGHJ5) associated with rheumatoid factor activity, a previously reported feature of eMZL in pSS. In conclusion, our results indicate that eMZL clonotypes in pSS patients are detectable prior to overt eMZL diagnosis in both tissue biopsies and peripheral blood through immunogenetic sequencing, paving the way for the development of improved methods of early detection of eMZL.

Radiomic Features Associated with Lymphoma Development in the Parotid Glands of Patients with Primary Sjögren’s Syndrome

Non-Hodgkin Lymphoma (NHL) represents a severe complication and the main cause of morbidity in patients with primary Sjögren's syndrome (pSS). This study aimed to assess the role of textural analysis (TA) in revealing lymphoma-associated imaging parameters in the parotid gland (PG) parenchyma of patients with pSS. This retrospective study included a total of 36 patients (54.93 ± 13.34 years old; 91.6% females) diagnosed with pSS according to the American College of Rheumatology and the European League Against Rheumatism criteria (24 subjects with pSS and no lymphomatous proliferation; 12 subjects with pSS and NHL development in the PG, confirmed by the histopathological analysis). All subjects underwent MR scanning between January 2018 and October 2022. The coronal STIR PROPELLER sequence was employed to segment PG and perform TA using the MaZda5 software. A total of 65 PGs underwent segmentation and texture feature extraction (48 PGs were included in the pSS control group, and 17 PGs were included in the pSS NHL group). Following parameter reduction techniques, univariate analysis, multivariate regression, and receiver operating characteristics (ROC) analysis, the following TA parameters proved to be independently associated with NHL development in pSS: CH4S6_Sum_Variance and CV4S6_Inverse_Difference_Moment, with an area under ROC of 0.800 and 0.875, respectively. The radiomic model (resulting by combining the two previously independent TA features), presented 94.12% sensitivity and 85.42% specificity in differentiating between the two studied groups, reaching the highest area under ROC of 0.931 for the chosen cutoff value of 1.556. This study suggests the potential role of radiomics in revealing new imaging biomarkers that might serve as useful predictors for lymphoma development in patients with pSS. Further research on multicentric cohorts is warranted to confirm the obtained results and the added benefit of TA in risk stratification for patients with pSS.

Active-Support Integrated Control Method for Renewable Energy Generation Voltage Source Converters

Aiming at the grid connection stability of renewable energy generation Voltage Source Converters (VSCs), an active support integrated control strategy is proposed in this article. First, the standard third-order model based on synchronous generator is established, and the renewable energy generation VSCs are equivalent to an approximate synchronous voltage source with the excitation system and speed regulation system. Second, an improved virtual impedance control is added on the basis of the model, which can reduce the impact of impulse current and improve the reactive power support capacity during fault by switching the virtual impedance during fault. At the same time, a virtual dual PSS control is added to the model, and the damping torque method is used to provide positive damping torque for the system and improve the oscillation suppression ability of the system. Finally, a simulation system is built to verify the correctness and effectiveness of the proposed control strategy.

Coordinated control of PI type PSS and MISO PI type SSSC-based damping controller design using improved grasshopper optimisation algorithm

Coordinated control of PI type PSS and MISO PI type SSSC-based damping controller design using improved grasshopper optimisation algorithm

Coordinated control of PI type PSS and MISO PI type SSSC-based damping controller design using improved grasshopper optimisation algorithm

Coordinated control of PI type PSS and MISO PI type SSSC-based damping controller design using improved grasshopper optimisation algorithm

A Pilot Study: Hypertension, Endothelial Dysfunction and Retinal Microvasculature in Rheumatic Autoimmune Diseases.

Background: The etiology of autoimmune rheumatic diseases is unknown. Endothelial dysfunction and premature atherosclerosis are commonly seen in these patients. Atherosclerosis is considered one of the main causes of cardiovascular diseases. Hypertension is considered the most important traditional cardiovascular risk. This case-control study aimed to investigate the relationship between autoimmune diseases and cardiovascular risk. Methods: This study was carried out in patients with rheumatoid arthritis, RA (n = 10), primary Sjögren syndrome, PSS (n = 10), and healthy controls (n = 10). Mean blood pressure (MBP), systolic blood pressure (SBP), diastolic blood pressure (DBP), and pulse wave velocity (PWV, an indicator of arterial stiffness) were assessed via a Vicorder device. Asymmetric dimethylarginine (ADMA) was measured via ELISA. Retinal photos were taken via a CR-2 retinal camera, and retinal microvasculature analysis was carried out. T-tests were conducted to compare the disease and control groups. ANOVA and ANOVA—ANCOVA were also used for the correction of covariates. Results: A high prevalence of hypertension was seen in RA (80% of cases) and PSS (40% of cases) compared to controls (only 20% of cases). Significant changes were seen in MBP (RA 101 ± 11 mmHg; PSS 93 ± 10 mm Hg vs. controls 88 ± 7 mmHg, p = 0.010), SBP (148 ± 16 mmHg in RA vs. 135 ± 16 mmHg in PSS vs. 128 ± 11 mmHg in control group; p = 0.007), DBP (77 ± 8 mmHg in RA, 72 ± 8 mmHg in PSS vs. 67 ± 6 mmHg in control; p = 0.010 in RA compared to the controls). Patients with PSS showed no significant difference as compared to controls (MBP: p = 0.240, SBP: p = 0.340, DBP: p = 0.190). Increased plasma ADMA was seen in RA (0.45 ± 0.069 ng/mL) and PSS (0.43 ± 0.060 ng/mL) patients as compared to controls (0.38 ± 0.059 ng/mL). ADMA in RA vs. control was statistically significant (p = 0.022). However, no differences were seen in ADMA in PSS vs. controls. PWV and retinal microvasculature did not differ across the three groups. Conclusions: The prevalence of hypertension in our cohort was very high. Similarly, signs of endothelial dysfunction were seen in autoimmune rheumatic diseases. As hypertension and endothelial dysfunction are important contributing risk factors for cardiovascular diseases, the association of hypertension and endothelial dysfunction should be monitored closely in autoimmune diseases.

Pain and fatigue are predictors of quality of life in primary Sj\xf6gren\u2019s syndrome

BackgroundFew studies have evaluated the relation of quality of life (QoL) with symptoms and disease activity in primary Sjögren’s syndrome (pSS). There is also scant information on the predictors of QoL in this population. The aim of this study was to assess QoL in patients with pSS and to investigate their possible predictors.MethodsIn a cross-sectional study, 77 patients with pSS were evaluated using the following questionnaires: Functional Assessment of Chronic Illness Therapy Fatigue Subscale (FACIT-Fatigue), EULAR Sjögren’s Syndrome Patient Reported Index (ESSPRI), EULAR Sjögren’s Syndrome Disease Activity Index (ESSDAI), Short Form-36 Health Survey (SF-36) and World Health Organization Quality of Life Assessment (WHOQOL-BREF). Seventy-seven healthy controls responded to the SF-36 and WHOQOL-BREF. The Mann-Whitney test, t-test, Pearson and Spearman correlation, and multiple regression analysis were used in the statistical analysis.ResultsPatients with pSS and healthy controls were matched by gender and age. The mean scores for the ESSDAI, ESSPRI and FACIT-Fatigue were 3.34 ± 4.61, 6.58 ± 2.29 and 26.17 ± 11.02, respectively. Patients had a lower employment rate (36.4% versus 62.3%, p < 0.01) and higher work disability (10.4% versus 1.3%, p < 0.01). SF-36 and WHOQOL-BREF values were lower in patients with pSS (p < 0.001), except in the WHOQOL-BREF environment domain. Pain (ESSPRI), fatigue (FACIT-Fatigue), antinuclear antibody (ANA), anti-Ro-SSA and economic class (Brazilian Economic Classification Criteria - CCEB) were independent predictors of QoL.ConclusionsThe main predictors of poor QoL in patients with pSS were pain and fatigue, and these symptoms had an impact regardless of disease activity, age, schooling, marital status, work disability and fibromyalgia.

Combustion Processed Nickel Oxide and Zinc Doped Nickel Oxide Thin Films as a Hole Transport Layer for Perovskite Solar Cells

Combustion processed nickel oxide (NiOx) thin film is considered as an alternative to the sol-gel processed hole transport layer for perovskite solar cells (PSCs). In this paper, NiOx thin film was prepared by the solution–combustion process at 250 °C, a temperature lower than the actual reaction temperature. Furthermore, the properties of the NiOx hole transport layer (HTL) in PSCs were enhanced by the incorporation of zinc (Zn) in NiOx thin films. X-ray diffraction and X-ray photoelectron spectroscopy results revealed that the formation of NiOx was achieved at lower annealing temperature, which confirms the process of the combustion reaction. The electrical conductivity was greatly improved with Zn doping into the NiOx crystal lattice. Better photoluminescence (PL) quenching, and low PL lifetime decay were responsible for better charge separation in 5% Zn doped NiOx, which results in improved device performance of PSCs. The maximum power conversion efficiency of inverted PSCs made with pristine NiOx and 5% Zn-NiOx as the HTL was 13.62% and 14.87%, respectively. Both the devices exhibited better stability than the PEDOT:PSS (control) device in an ambient condition.

Is it possible to not perform salivary gland biopsy in targeted patients according to unstimulated salivary flow results in patients with suspected Sj\xf6gren's syndrome?

Introduction/objectiveXerostomia is one of the main symptoms of primary Sjögren's syndrome (pSS). The unstimulated salivary flow (UWS) test is one of the objective Sjögren's syndrome classification criteria used to assess xerostomia's severity. The study’s objective was to evaluate UWS rate measurements (with a threshold rate of 0.1 mL/min) in the screening of patients suspected with pSS, presenting with xerostomia in whom labial salivary gland biopsy (LSGB) should be performed. We will try to answer whether it is possible not to perform LSGB in targeted patients according to UWS results? We analyze the correlation between UWS value and focus score (FS) and anti-SSA antibodies.MethodsThe study group consisted of subjects above 18 years of age with a subjective feeling of oral dryness.ResultsA total of 105 subjects were qualified for the study. The final diagnosis of pSS was made in 44 patients according to the classification criteria from 2016. No age differences were identified between pSS patients and control group subjects (patients with dry mouth without autoimmune background). UWS rates were significantly lower in pSS patients than in the control group. No association was identified between UWS and focus score (FS) ≥ 1 in LSGB. No differences were observed between anti-SSA-positive and anti-SSA-negative patients in terms of age, UWS rates, FS.ConclusionLSGB should be performed in all suspected pSS cases regardless of the UWS rate value, particularly in subjects without specific anti-SSA antibodies. In patients with suspected pSS, only less than one-half of the UWS measurements are below the value of 0.1 mL/min adopted as the threshold in the classification criteria for pSS.

Design of Coordinated Control of PSS and TCSC using LQR Optimal Controller

Design of Coordinated Control of PSS and TCSC using LQR Optimal Controller

Design of Fuzzy TS-PDC Controller for Electrical Power System via Rules Reduction Approach

In this paper, a new Takagi–Sugeno Fuzzy Logic controller (TS-FLC) is presented and applied for modeling and controlling the nonlinear power systems even in the presence of disturbances. Firstly, a nonlinear mathematical model for the electrical power system is presented with consideration of PSS and AVR controller. Then, a Takagi–Sugeno Fuzzy Logic controller is employed to control power system stability. Nevertheless, the study of the stability of Takagi–Sugeno fuzzy models will be difficult in the case where the number of nonlinearities is important. To cope with this problem, this study proposed a methodology to reduce the number of rules and to guarantee the global stability of the power system. The new model included only two rules. All the other nonlinearities were considered as uncertainties. In addition, a Parallel Distributed Compensation controller is designed using the Linear Matrix Inequalities constraints in order to guarantee system stability. Finally, this approach is applied on a Single Machine Infinite Bus affected by fault perturbation. To show the novelty of Takagi Sugeno’s method, we compared our approach to the Taylor linearization method. The numerical simulations prove the feasibility and performance of the proposed method.

Primary Sjögren's Syndrome of Early and Late Onset: Distinct Clinical Phenotypes and Lymphoma Development.

ObjectivesTo study the clinical, serological and histologic features of primary Sjögren’s syndrome (pSS) patients with early (young ≤35 years) or late (old ≥65 years) onset and to explore the differential effect on lymphoma development.MethodsFrom a multicentre study population of 1997 consecutive pSS patients, those with early or late disease onset, were matched and compared with pSS control patients of middle age onset. Data driven analysis was applied to identify the independent variables associated with lymphoma in both age groups.ResultsYoung pSS patients (19%, n = 379) had higher frequency of salivary gland enlargement (SGE, lymphadenopathy, Raynaud’s phenomenon, autoantibodies, C4 hypocomplementemia, hypergammaglobulinemia, leukopenia, and lymphoma (10.3% vs. 5.7%, p = 0.030, OR = 1.91, 95% CI: 1.11–3.27), while old pSS patients (15%, n = 293) had more frequently dry mouth, interstitial lung disease, and lymphoma (6.8% vs. 2.1%, p = 0.011, OR = 3.40, 95% CI: 1.34–8.17) compared to their middle-aged pSS controls, respectively. In young pSS patients, cryoglobulinemia, C4 hypocomplementemia, lymphadenopathy, and SGE were identified as independent lymphoma associated factors, as opposed to old pSS patients in whom SGE, C4 hypocomplementemia and male gender were the independent lymphoma associated factors. Early onset pSS patients displayed two incidence peaks of lymphoma within 3 years of onset and after 10 years, while in late onset pSS patients, lymphoma occurred within the first 6 years.ConclusionPatients with early and late disease onset constitute a significant proportion of pSS population with distinct clinical phenotypes. They possess a higher prevalence of lymphoma, with different predisposing factors and lymphoma distribution across time.

Detection of nerve enlargement with ultrasound and correlation with skin biopsy findings in painful sensory neuropathy associated with Sjögren’s syndrome

Objectives We evaluated usefulness of peripheral nerve ultrasound (US) in detecting abnormality in painful sensory neuropathy (PSN) associated with primary Sjögren’s syndrome (pSS), and associations among various clinical factors, US findings, and intraepidermal nerve fiber density (IENFD). Methods We conducted a retrospective, single-center, observational study of patients with pSS-PSN. US image was obtained to measure cross sectional area (CSA) of peripheral nerves and compared with matched pSS control. Results We included 11 patients with pSS-PSN (10 women; age 70.5 ± 5.66) and 17 pSS controls (15 women; age 62.5 ± 16.7). Sural nerve CSA were significantly increased in pSS-PSN group (3.48 ± 1.0 mm2 vs 2.05 ± 0.65 mm2, p = .001). US of sural nerve showed the area under the ROC curve of 0.872 (95% CI, 0.732 − 1). Sural nerve CSA and IENFD of lower leg showed positive correlation. Compared with pSS-PSN patients with abnormal IENFD, those with normal IENFD showed significantly larger sural nerve CSA, and trends toward less systemic disease activity and small fiber impairment with sparing of large fibers. Conclusion US was useful in discriminating pSS patients with PSN from those without. Additionally, US may disclose distinct subsets of pSS-PSN with different clinical findings and IENFD.

Study of Dynamic Stability Analysis in the Sigura-gura Hydro Power Plant using the Power Stabilizer System as Compensation

To maintain the stability of the power plant system, effort are needed to keep the generator in sync. This study was conducted to determine the performance of each power plant in the Sigura-gura power system when interference with the transmission network. By reviewing the response curve through simulations with the EDSA software, it can be seen the changes in rotor angle, voltage oscillation and power for each generating system when a disturbance occurs. The application of PSS as a compensation to improve the character of the power system’s stability against interference by observing changes in rotor angle, voltage and power. The observations show that the installation of PSS controllers in excitation as compensation to the Sigura-gura electric power system can contribute to better system performance by improving the rotor angle oscillation time, voltage and overshoot respectively 7.8%, 66.6% and 37.9%.

Optimal Coordinated Design of PSS and UPFC-POD Controller Using Dolphin Echolocation Optimization Algorithm for Damping Oscillation

Optimal Coordinated Design of PSS and UPFC-POD Controller Using Dolphin Echolocation Optimization Algorithm for Damping Oscillation

Organogels Based on PEDOT:PSS and Carbon‐dots for Efficient Hole Transport in Organic Photovoltaics

J–V characteristics of the OPVs with PEDOT: PSS (control) and ogC0.2 as HTLs.

Robust PI, gain scheduled and PSS controller design using LMI regions: Comparative studies

Abstract This paper considers development of a new design procedure for PI and Gain scheduled robust controller with PSS for turbogenerator using LMI regional regions. The obtained PI+PSS and GSC+PSS robust controllers with output and state derivative feedback for uncertain polytopic turbogenerator model ensure that all closed -loop eigenvalues lay in the prescribed LMI region. The proposed method is to guarantee the less conservativeness with respect to previous methods due to introducing a design procedure based on new auxiliary matrices. The effectiveness of this procedure is illustrated by the examples of two controllers for turbogenerator.