Rate Control Strategy Research Articles

Dubious effect of the high biventricular paced beats percentage itself on the cardiac resynchronization efficacy in patients with atrial fibrillation. The randomized Pilot-CRAfT Study results

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Institute of Cardiology statutory grant Background The presence of atrial fibrillation (AF) in cardiac resynchronization therapy (CRT) recipients is common and AF is a marker of poorer CRT response. The negative influence of AF on CRT efficacy is belived to be mediated mainly by the drop of effectively captured biventricular paced beats percentage (BiVp%). According to observational trials, the minimal BiVp associated with better outcomes is 95-98%, however there is lack of randomized trials to confirm this findings. Purpose The purpose of the study was to assess the influence of BiVp% itself on the clinical outcomes in the population CRT patients with atrial fibrillation in a prospective, randomized cohort. Methods The study included the prospective Pilot-CRAfT study participants that is patients with CRT and permanent or persistent AF lasting for ≥6 months that were randomly assigned to rhythm or rate control strategy. We divided the whole study population according to their BiVp at the 12 month follow-up with two borderline BiVp values (BiVp >98% vs <98% and >95% vs <95%) and analysed the echocardiographic indices, exercise tolerance and quality of life between the prespecified groups. Results The study included 43 CRT patients (97,7% males) aged 68,4 (SD: ±8,3) years with mean BiVp% 82,4% ±9,7% at baseline. The mean baseline left ventricular ejection fraction (LVEF), left ventricular end diastolic diameter (LVEDD) and maximal oxygen uptake (VO2max) were: 30 ±8%, 65 ±8 mm, 14 ±5 mL/(kg*min), respectively. In both of the study arms the BiVp% raised significantly reaching 98,1 ±2,3% and 96,3 ±3,9% in the rhythm control and the rate control arms respectively (P=0,093). As a result the were overall 21 patients with BiVp >98% and 29 patients with BiVp >95% at the end of the study. The BiVp groups >98% vs <98% and >95% vs <95% did not differ as to baseline characteristics and we have not observed any differences in the mean LVEF, mean LVEDD, mean VO2max, and quality of life in the prespecified BiVp% groups at the end of the follow up. Moreover no linear correlations between the BiVp% and LVEF, LVEDD, VO2max values were observed. However, in the rate control group patients with AVNA performed had lower LVEDD at the end of the study (57,7 ±3,0 vs 65,4 ±7,0 p=0,007) and significant decrease in the LVEDD after AVNA was observed (-8,6 95%CI [-14,9; -2,3]). Conclusions The BiVp >98% or >95% alone does not seem to warrant good response to cardiac resynchronization in patients with persistent atrial fibrillation as assessed in the prospective randomized cohort. However, performing AVNA in this group of patients may be beneficial in terms of LVEDD decrease.

Atrial Fibrillation and Heart Failure

Atrial fibrillation (AF) is the most common sustained arrhythmia worldwide and has a strong association with heart failure (HF). It often remains unclear if HF is the cause or consequence of AF due to the complexity of the processes that are involved in both the perpetuation of AF and the development of HF. To date, two therapeutic strategies are accepted as the standard of care in AF patients with heart failure. Rhythm control aims to permanently restore sinus rhythm, whereas a rate-control strategy aims to slow ventricular rate without the termination of AF. In the last 5 years a tremendous number of important studies have been published investigating the optimal therapeutic strategy in HF patients. This review highlights the important studies with respect to the involvement of AF in promoting left-ventricular dysfunction and discusses the optimal strategy in HF patients suffering from AF.

Advances in Clinical Cardiology 2021: A Summary of Key Clinical Trials.

IntroductionOver the course of 2021, numerous key clinical trials with valuable contributions to clinical cardiology were published or presented at major international conferences. This review seeks to summarise these trials and reflect on their clinical context.MethodsThe authors reviewed clinical trials presented at major cardiology conferences during 2021 including the American College of Cardiology (ACC), European Association for Percutaneous Cardiovascular Interventions (EuroPCR), European Society of Cardiology (ESC), Transcatheter Cardiovascular Therapeutics (TCT), American Heart Association (AHA), European Heart Rhythm Association (EHRA), Society for Cardiovascular Angiography and Interventions (SCAI), TVT-The Heart Summit (TVT) and Cardiovascular Research Technologies (CRT). Trials with a broad relevance to the cardiology community and those with potential to change current practice were included.ResultsA total of 150 key cardiology clinical trials were identified for inclusion. Interventional cardiology data included trials evaluating the use of new generation novel stent technology and new intravascular physiology strategies such as quantitative flow ratio (QFR) to guide revascularisation in stable and unstable coronary artery disease. New trials in acute coronary syndromes focused on shock, out of hospital cardiac arrest (OOHCA), the impact of COVID-19 on ST-elevation myocardial infarction (STEMI) networks and optimal duration/type of antiplatelet treatment. Structural intervention trials included latest data on transcatheter aortic valve replacement (TAVR) and mitral, tricuspid and pulmonary valve interventions. Heart failure data included trials with sodium-glucose cotransporter 2 (SGLT2) inhibitors, sacubitril/valsartan and novel drugs such as mavacamten for hypertrophic cardiomyopathy (HCM). Prevention trials included new data on proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors. In electrophysiology, new data regarding atrial fibrillation (AF) screening and new evidence for rhythm vs. rate control strategies were evaluated.ConclusionThis article presents a summary of key clinical cardiology trials published and presented during the past year and should be of interest to both practising clinicians and researchers.

Congestion and Computer Program Control Algorithm Strategy for Wireless Sensor Networks Based on Cloud Model

Cloud model and sensor network are the research hotspots in recent years. This paper proposes a congestion and rate control strategy for wireless sensor networks based on cloud model. It adjusts the input rate of nodes based on cloud model through node congestion detection. Aiming at the problem of network congestion control, two congestion adjustment algorithms based on red are improved. Congestion threshold and congestion degree are used as the basis of packet transmission rate adjustment to realize network support plug control. In this paper, the congestion control strategy NP starts to alleviate congestion at about 40 s and controls the packet loss rate at about 116 packets/s, which is 45.3% lower than the multipath congestion control strategy and is more stable. However, when β = 0 , the packet loss rate of the double congestion threshold algorithm is 20% lower than that of the single congestion threshold algorithm. The reason is that the double congestion threshold algorithm allows a stronger source rate control mechanism earlier than the single congestion threshold algorithm a large number of packets are lost in a point, but this also makes the network performance relatively low.

Rhythm Control Better Prevents Dementia than Rate Control Strategies in Patients with Atrial Fibrillation-A Nationwide Cohort Study.

Background: Atrial fibrillation (AF) increases the risk of dementia. Whether the pharmacological rhythm control of AF can reduce the risk of dementia compared to the rate control strategy remains unclear. We hypothesize that the rhythm control strategy is better than the rate control strategy in preventing dementia. Methods: AF patients aged ≥65 years were identified from the Taiwan National Health Insurance Database. Patients receiving anti-arrhythmic drugs at a cumulative defined daily dose (cDDD) of >30 within the first year of enrollment constituted the rhythm control group. Patients who used rate control medications for a cDDD of >30 constituted the rate control group. A multivariate Cox hazards regression model was used to determine the hazard ratio (HR) for dementia. Results: A total of 3382 AF patients (698 in the rhythm control group; 2684 in the rate control group) were analyzed. During a 4.86 ± 3.38 year follow-up period, 414 dementia events occurred. The rhythm control group had a lower rate of dementia than the rate control group (adjust HR: 0.75, p = 0.031). The rhythm control strategy reduced the risk of dementia particularly in those receiving aspirin (p = 0.03). Conclusions: In patients with AF, pharmacological rhythm control was associated with a lower risk of dementia than rate control over a long-term follow-up period, particularly in patients receiving aspirin treatment.

Anti-slip Control for Unmanned Underwater Tracked Bulldozer Based on Active Disturbance Rejection Control

The unmanned underwater tracked bulldozer (UUTB) plays an essential role in dredging and clearing riverbed obstacles in flood season. The track slip leads to instability and energy consumption while the UUTB sinkage into the soft sediment on the riverbed. The track anti-slip control strategy is proposed based on active disturbance rejection control (ADRC) in this article. An identification strategy of optimal slip rate is investigated by the method of adaptive step coefficient. The motion model of UUTB is established by the RecurDyn environment. The track traction system, anti-slip controller and adaptive slip rate identification strategy are established in the MATLAB/Simulink environment. The ADRC based anti-slip rate control strategy is verified by the co-simulation of RecurDyn and MATLAB/simulink. Two conditions with different slippery ground is established to verify the anti-slip rate control strategy. Simulation and experimental results indicate that the proposed ADRC-based anti-slip rate control strategy can effectively reduce the slip rate and improve the operating stability of the UUTB prototype. The significance of this paper is to alleviate the problem of poor mobility caused by track slipping when the UUTB underwater operation.

Analysis of Slip rate Control Technology of Electric Vehicle Based on Sliding Mode Algorithm

With the increasingly prominent environmental and energy problems, it is very important to strengthen the research of new energy vehicles. In the research process of new energy vehicles, the safety of electric vehicles during driving is extremely important. In the braking process of electric vehicles, wheel slip control is an important factor to ensure the safety of electric vehicles. In the process of slip rate control, it is necessary to identify the wheel slip rate under different road surfaces, so as to complete the design of the slip rate controller on the basis of mastering the wheel friction characteristics. In this research, we mainly consider the maximum braking torque limit of motor output, scientifically distribute regenerative braking and hydraulic braking torque, complete the design of slip rate controller based on sliding mode algorithm, and introduce saturation function to solve the buffeting problem in road friction adaptive slip rate control method. Put forward the core of slip rate control strategy of electric vehicle. Through research, it is determined that the reasonable division of regenerative braking and mechanical braking based on slip rate can improve the safety of vehicle braking and ensure the efficiency of energy recovery. Therefore, in the process of electric vehicle slip rate control, the regenerative braking control method based on slip rate closed-loop control has application value.

Atrial Fibrillation Management: A Comprehensive Review with a Focus on Pharmacotherapy, Rate, and Rhythm Control Strategies.

Atrial fibrillation (AF) is an increasingly common arrhythmia encountered in clinical practice that leads to a substantial increase in utilization of healthcare services and a decrease in the quality of life of patients. The prevalence of AF will continue to increase as the population ages and develops cardiac comorbidities; thus, prompt and effective treatment is important to help mitigate systemic resource utilization. Treatment of AF involves two tenets: prevention of stroke and systemic embolism and symptom control with either a rate or a rhythm control strategy. Historically, due to the safe nature of medications like beta-blockers and non-dihydropyridine calcium channel blockers, used in rate control, it has been the initial strategy used for symptom control in AF. Newer data suggest that a rhythm control strategy with antiarrhythmic medications with or without catheter ablation may lead to a reduction in major adverse cardiovascular events, particularly in patients newly diagnosed with AF. Modulation of factors that promote AF or its complications is another important aspect of the overall holistic management of AF. This review provides a comprehensive focus on the management of patients with AF and an in-depth review of pharmacotherapy of AF in the rate and rhythm control strategies.

Rhythm control versus rate control in patients with atrial fibrillation and heart failure across the left ventricular ejection fraction spectrum

BackgroundRhythm control and rate control are both employed commonly in patients with atrial fibrillation (AF) and heart failure (HF), but limited real-world data exist on them. We aimed to compare outcomes between these two strategies across the left ventricular ejection fraction (LVEF) spectrum. Materials and methodsThis retrospective cohort study used data from the randomized MISOAC-AF trial, including from patients with AF and coexistent HF who were hospitalized and followed up after discharge. At baseline, the patients were classified into pharmaceutical (or electrical cardioversion) rhythm control strategy or rate control treatment (b-blocker, digoxin, calcium channel blockers) groups. The primary outcome was all-cause mortality. Kaplan-Meier curves and multivariable-adjusted Cox regression were utilized to compare the two strategies. Spline curve models were used to demonstrate the results across the LVEF stratified spectrum. ResultsIn total, 199 AF patients with HF were studied (mean age, 77 years). At discharge, 73 (36.7%) patients received rhythm control and 126 (63.3%) rate control treatment. After a median follow-up period of 31 months, 26 (35.6%) patients in the rhythm-control group died, as compared to 43 (33.3%) in the rate-control group (aHR: 1.29; 95% CI: 0.78-2.14; p = 0.31). The spline curves also revealed no difference in all-cause mortality favoring either strategy in any HF subtype across the nominally classified LVEF. ConclusionThe use of a pharmacological rhythm-control strategy was not associated with a survival advantage compared to the rate control strategy in recently hospitalized patients with AF and comorbid HF. More randomized trials and large studies are needed in the future to explore these results in each subgroup of HF patients.

Rate versus rhythm control for atrial fibrillation: from AFFIRM to EAST-AFNET 4 -a paradigm shift.

The clinical choice between rate or rhythm control therapies has been debated over the years. In 2002, the AFFIRM trial demonstrated that the rhythm-control strategy had no survival advantage over the rate-control strategy. Eighteen years later, EAST-AFNET 4 showed that the rhythm-control approach is better than rate control in reducing adverse cardiovascular outcomes in patients with a recent diagnosis of atrial fibrillation (AF). During the time between AFFIRM and EAST-AFNET 4, rhythm control understanding, specifically ablation, improved, while rate-control strategies remained the same possibly leading to the change in results seen in EAST-AFNET 4. This review seeks to evaluate the rate- and rhythm-control strategies, focusing on the important clinical trials in the past two decades. These trials have shown great advancement in AF management; however, the search for the best approach to controlling AF and minimizing the burden of symptoms is still a work in progress and needs further research.

Flow rate control in standing column wells: A flexible solution for reducing the energy use and peak power demand of the built environment

Standing column wells offer a generous and flexible solution to improve the energy efficiency of the built environment. As these systems behavior is strongly affected by groundwater advection, the acute challenge of predicting their thermal evolution with both accuracy and computational efficiency has so far hindered the development of design tools and optimized control strategies. In this work, a powerful simulation algorithm is implemented and applied to the performance assessment of multi-borehole standing column well systems located in a heterogeneous geological environment and operating under various constant and dynamic flow rate control strategies. The iterative algorithm relies on the non-stationary convolution technique to simulate the underground components, and the EnergyPlus approach to represent the heat pump efficiency at full and part loads. The findings suggest that using higher flow rates in peak conditions is a key element that minimizes auxiliary assistance and power demand. Complementary variable flow rate control aiming to maintain a 2 °C temperature difference across the plate heat exchanger has shown to alleviate groundwater usage and generate at least 8%–11% annual energy savings compared with constant flow. This operating strategy allowed the systems to deliver 197–246 W/m with a heating seasonal performance factor of 3.59. These results were achieved through 34 annual simulations having hourly time steps that were performed with the proposed algorithm in a total of 4 h 17 min, compared to 11 days for a single simulation using a numerical reference model.

Rate vs Rhythm Control Strategy for Atrial Fibrillation in 2022

Atrial fibrillation (AF) is a chronic and evolving condition; patients need to be explained that management could require repeated, changing, and combination of interventions. This article is intended to present and emphasize new information that was published last year regarding the suitability of rate vs rhythm control strategy for management of AF.

A thermal-hydraulic coupled simulation approach for the temperature and flow rate control strategy evaluation of the multi-room radiator heating system

The lack of efficient temperature and flow rate control strategy is one of the key factors in excessive energy consumption of the district heating (DH) system. The current researches on secondary network simulation and control usually tackle the hydraulic characteristics of the network and building thermal dynamic separately. However, for the multi-room radiator heating system, the hydraulic characteristics and building thermal dynamics are coupled. An effective coupled thermal-hydraulic model for simulation and control of multi-room radiator heating systems is essential. In this paper, a novel thermal-hydraulic coupled simulation approach is proposed. The temperature distribution and thermal capacity of the radiator, as well as the hydraulic characteristics of the radiator heating network, are considered. A numerical method is developed to solve the proposed model. Different control strategies are analyzed based on the model. Result shows that efficient terminal flow rate control can save 8.4%–13% energy. The proportional control is superior to the on-off control in maintaining indoor temperature, while their energy consumptions are the same. Additionally, the hydraulic coupling effect of the network between households and floors should be considered if the balance valves are not installed on each floor.

Atrial Fibrillation and Dementia: A Report From the AF-SCREEN International Collaboration

Growing evidence suggests a consistent association between atrial fibrillation (AF) and cognitive impairment and dementia that is independent of clinical stroke. This report from the AF-SCREEN International Collaboration summarizes the evidence linking AF to cognitive impairment and dementia. It provides guidance on the investigation and management of dementia in patients with AF on the basis of best available evidence. The document also addresses suspected pathophysiologic mechanisms and identifies knowledge gaps for future research. Whereas AF and dementia share numerous risk factors, the association appears to be independent of these variables. Nevertheless, the evidence remains inconclusive regarding a direct causal effect. Several pathophysiologic mechanisms have been proposed, some of which are potentially amenable to early intervention, including cerebral microinfarction, AF-related cerebral hypoperfusion, inflammation, microhemorrhage, brain atrophy, and systemic atherosclerotic vascular disease. The mitigating role of oral anticoagulation in specific subgroups (eg, low stroke risk, short duration or silent AF, after successful AF ablation, or atrial cardiopathy) and the effect of rhythm versus rate control strategies remain unknown. Likewise, screening for AF (in cognitively normal or cognitively impaired patients) and screening for cognitive impairment in patients with AF are debated. The pathophysiology of dementia and therapeutic strategies to reduce cognitive impairment warrant further investigation in individuals with AF. Cognition should be evaluated in future AF studies and integrated with patient-specific outcome priorities and patient preferences. Further large-scale prospective studies and randomized trials are needed to establish whether AF is a risk factor for cognitive impairment, to investigate strategies to prevent dementia, and to determine whether screening for unknown AF followed by targeted therapy might prevent or reduce cognitive impairment and dementia.

A frame level rate allocation algorithm based on temporal dependency model for AV1

Rate control is an essential module in video coding. Rate control strategies strive to deliver a stable playback experience as well as achieving high compression efficiency for modern video applications, constrained by restricted bandwidth and buffer limits. The difficulty of rate control often lies in the adaptation ability of the underlying algorithm to capture the variability of content and temporal correlation across frames. In this paper, we present a rate allocation algorithm to model the distortion propagation in the hierarchical coding structure premised on the temporal dependency model at frame level. Our experiments show that with the information collected from the temporal dependency model, the proposed rate allocation algorithm significantly improves the coding efficiency over the AV1 baseline on a set of variable user generated video clips.

Association of rhythm control with incident dementia among patients with atrial fibrillation: a nationwide population-based cohort study.

Atrial fibrillation (AF) increases the risk of dementia, and catheter ablation of AF may be associated with a lower risk of dementia. We investigated the association of a rhythm-control strategy for AF with the risk of dementia, compared with a rate-control strategy. This population-based cohort study included 41,135 patients with AF on anticoagulation who were newly treated with rhythm-control (anti-arrhythmic drugs or ablation) or rate-control strategies between 1 January 2005 and 31 December 2015 from the Korean National Health Insurance Service database. The primary outcome was all-cause dementia, which was compared using propensity score overlap weighting. In the study population (46.7% female; median age: 68years), a total of 4,039 patients were diagnosed with dementia during a median follow-up of 51.7months. Rhythm control, compared with rate control, was associated with decreased dementia risk (weighted incidence rate: 21.2 versus 25.2 per 1,000 person-years; subdistribution hazard ratio [sHR] 0.86, 95% confidence interval [CI] 0.80-0.93). The associations between rhythm control and decreased dementia risk were consistently observed even after censoring for incident stroke (sHR 0.89, 95% CI 0.82-0.97) and were more pronounced in relatively younger patients and those with lower CHA2DS2-VASc scores. Among dementia subtypes, rhythm control was associated with a lower risk of Alzheimer's disease (sHR 0.86, 95% CI 0.79-0.95). Among anticoagulated patients with AF, rhythm control was associated with a lower risk of dementia, compared with rate control. Initiating rhythm control in AF patients with fewer stroke risk factors might help prevent subsequent dementia.

SolarReceiver2D: a Modelica Package for Dynamic Thermal Modelling of Central Receiver Systems

This paper describes the Modelica Package SolarReceiver2D which has been developed for the dynamic thermal analysis of central receiver systems. The package includes all the components necessary for the dynamic simulation of the solar receiver operation and it enables consideration of different receiver geometries, materials, HTFs, and operating conditions (e.g., HTF mass flow rate control strategies, heat flux, ambient conditions). Some of the package components are taken from existing Modelica libraries originally developed to model water and gas flows, while other are implemented as new components. The SolarReceiver2D package allows assessment of the receiver thermal efficiency and the temperature distributions experienced by the tubes and the HTF during its operation. The tubes temperature field is modelled in the axial, circumferential, and radial directions, and this makes the package suited for a thermo-mechanical analysis of the receiver. Moreover, the receiver response to passing clouds is dynamically simulated accounting for the effect of thermal transients. The SolarReceiver2D represents a useful tool for the design and optimization of solar tower receivers.

Experience in the management of infants with multifocal atrial tachycardia

Purpose. To study the clinical course of multifocal atrial tachycardia (MAT) and to evaluate the effectiveness of antiarrhythmic therapy (AAT) in patients with onset of arrhythmia before the age of 1 year.Methods. The study included 15 children with primary registration of MAT at the age of 2.04±2.27 months, 4 of them - in utero. The follow-up period was 35.9±26.9 months (Me 29 months). All patients underwent laboratory monitoring, 12-lead ECG recording, 24-hour ECG monitoring, echocardiography at baseline and during time of observation.Results. Tachycardia was persistent in 80% of patients. Tachycardia-induced cardiomyopathy (TIC) was present in 7 (46%) patients. Structural heart disease was detected in 6 patients. The average heart rate at the onset of the disease was 157.9±23.78 bpm, the maximum - 256.7±35.84 bpm. Fourteen (93.3%) children received AAT. Seven patients were prescribed propranolol first, 6 - amiodarone, 1 - digoxin. Monotherapy was effective in 2 patients. Combined AAT was used in 12 patients, including three children with three drugs combination. No benefits were found for any of the drugs combinations. Stable sinus rhythm at the time of discharge was observed in 4 (28,6%) patients, sinus rhythm with atrial ectopic activity was registered in 2 of them; criteria for normosystole were achieved in 7 patients; in one child with TIC daytime tachysystole persisted despite three-component AAT, but echocardiography parameters improved. Arrhythmia was disappeared in 13 (86.6%) patients; the duration of arrhythmia in them from 1 to 15 months, duration of AAT - 1 ±7.5 months (Me 9.5 months). MAT persists in two patients with structural heart disease. One patient underwent radiofrequency ablation at the age of 5, with no effect. One patient had side effects from therapy that required correction. There were no lethal outcomes.Conclusion. MAT with a debut at the age of 1 year with timely prescribed treatment has a favorable course and a good prognosis, but the probability of AAT resistance is high. These cases require a long-term selection of therapy using various combinations of antiarrhythmic drugs. Heart rate control strategy can be sufficient to prevent the development of TIC.

Rhythm- or rate-control strategies according to 4S-AF characterization scheme and long-term outcomes in atrial fibrillation patients: the FAMo (Fibrillazione Atriale in Modena) cohort.

The 4S-AF scheme [Stroke risk, Symptom severity, Severity of atrial fibrillation (AF) burden, Substrate severity] was recently proposed to characterize AF patients. In this post hoc analysis we evaluated the agreement between the therapeutic strategy (rate or rhythm control, respectively), as suggested by the 4S-AF scheme, and the actual strategy followed in a patients cohort. Outcomes of interest were as follows: all-cause death, a composite of all-cause death/any thromboembolism/acute coronary syndrome, and a composite of all-cause death, any thrombotic/ischemic event, and major bleeding (net clinical outcome). We enrolled 615 patients: 60.5% male, median age 74 [interquartile range (IQR) 67-80] years; median CHA2DS2VASc 4 and median HAS-BLED 2. The 4S-AF score would have suggested a rhythm-control strategy in 351 (57.1%) patients while a rate control in 264 (42.9%). The strategy adopted was concordant with the 4S-AF suggestions in 342 (55.6%) cases, and non-concordant in 273 (44.4%). After a median follow-up of 941days (IQR 365-1282), 113 (18.4%) patients died, 158 (25.7%) had an event of the composite endpoint. On adjusted Cox regression analysis, when 4S-AF score suggested rate control, disagreement with that suggestion was not associated with a worse outcome. When 4S-AF indicated rhythm control, disagreement was associated with a higher risk of all-cause death (HR 7.59; 95% CI 1.65-35.01), and of the composite outcome (HR 2.69; 95% CI 1.19-6.06). The 4S-AF scheme is a useful tool to comprehensively evaluate AF patients and aid the decision-making process. Disagreement with the rhythm control suggestion of the 4S-AF scheme was associated with adverse clinical outcomes.

Review of PV power ramp rate control methods and their requirements

Grid codes play a significant role in setting power system characteristics, such as ramp rate of different kinds of power plants. Using novel energy sources, like solar energy, for supplying electrical power demands, develops the requisite for controlling the characteristics of these sources such as their power ramp rates. While solar power is going to increase or decrease, ramp rate control is crucial. There have been suggested different strategies for power ramp rate control. Some of these strategies need batteries and some do not. Due to solar radiation uncertainties, it is necessary to use energy storage systems to control power ramp rate. On the other hand, batteries add huge costs and unreliability to the power systems. As a result, there is a trading-off among initial cost, reliability, security, and operation costs for selecting an optimal strategy. Also significance of the grid is a decisive factor. In this paper, some power ramp rate control schemes are discussed, and the advantages and disadvantages of different types of schemes have been analyzed. Also, in this literature different kinds of power ramp rate control strategies for photovoltaics have been clustered into some major sets. Besides, power ramp rate control is essential for novel schemes such as virtual synchronous machines, so emerging virtual inertia in novel power grids is another motivation to establish different methods for controlling the power ramp rate of renewable energy sources. Thus, in this paper, there is a section discussing the applications of power ramp rate control schemes.