Ramp-rate control strategy for distributed PV-ESS AC-stacked inverter architecture

Author(s):  
Namwon Kim ◽  
Babak Parkhideh
Solar Energy ◽  
2020 ◽  
Vol 208 ◽  
pp. 1058-1067
Author(s):  
Xingshuo Li ◽  
Huiqing Wen ◽  
Bingqing Chen ◽  
Shuye Ding ◽  
Weidong Xiao

2021 ◽  
Vol 11 (13) ◽  
pp. 5766
Author(s):  
Juan F. Patarroyo-Montenegro ◽  
Jesus D. Vasquez-Plaza ◽  
Omar F. Rodriguez-Martinez ◽  
Yuly V. Garcia ◽  
Fabio Andrade

One of the most important aspects that need to be addressed to increase solar energy penetration is the power ramp-rate control. In weak grids such as the one found in Puerto Rico, it is important to smooth power fluctuations caused by the intermittence of passing clouds. In this work, a novel power ramp-rate control strategy is proposed. Additionally, a comparison with some of the most common power ramp-rate control methods is performed using a proposed model and real solar radiation data from the Coto Laurel photovoltaic power plant located in Ponce, Puerto Rico. The proposed model was validated using one-year real data from Coto Laurel. The power ramp-rate control methods were compared in real-time simulations using the OP5700 from Opal-RT Technologies considering power ramp rate fluctuations, power ramp-rate violations, fluctuations in the state-of-charge, among other indicators. Moreover, the proposed power ramp-rate control strategy, called predictive dynamic smoothing was explained and compared. Results indicate that the predictive dynamic smoothing produced a considerably reduced Levelized Cost of Storage compared to other power ramp-rate control methods and provided a higher lifetime expectancy for lithium batteries.


TAPPI Journal ◽  
2018 ◽  
Vol 17 (05) ◽  
pp. 295-305
Author(s):  
Wesley Gilbert ◽  
Ivan Trush ◽  
Bruce Allison ◽  
Randy Reimer ◽  
Howard Mason

Normal practice in continuous digester operation is to set the production rate through the chip meter speed. This speed is seldom, if ever, adjusted except to change production, and most of the other digester inputs are ratioed to it. The inherent assumption is that constant chip meter speed equates to constant dry mass flow of chips. This is seldom, if ever, true. As a result, the actual production rate, effective alkali (EA)-to-wood and liquor-to-wood ratios may vary substantially from assumed values. This increases process variability and decreases profits. In this report, a new continuous digester production rate control strategy is developed that addresses this shortcoming. A new noncontacting near infrared–based chip moisture sensor is combined with the existing weightometer signal to estimate the actual dry chip mass feedrate entering the digester. The estimated feedrate is then used to implement a novel feedback control strategy that adjusts the chip meter speed to maintain the dry chip feedrate at the target value. The report details the results of applying the new measurements and control strategy to a dual vessel continuous digester.


2018 ◽  
Vol 88 (2) ◽  
Author(s):  
Stefano Fumagalli ◽  
Serena Boni ◽  
Simone Pupo ◽  
Marta Migliorini ◽  
Irene Marozzi ◽  
...  

Atrial fibrillation (AF) is the most frequent arrhythmia in elderly people. Findings derived from clinical trials seem to demonstrate that a rate-control strategy of AF in aged patients improves prognosis if compared to a rhythm-control one. However, epidemiological studies concordantly show that the arrhythmia is associated to increased hospitalization and mortality rates. In last years, the proportion of patients admitted to hospital for AF has progressively increased; this trend is observed in subjects >75 and >85 years, while no change was found in younger cohorts. Importantly, in aged individuals, probably because of the loss of atrial activity, the increase of heart rate and the irregularity of RR intervals, AF begins a vicious cycle, leading from heart failure, through the compromise of functional and neurocognitive status, to overt disability, dementia and increased mortality. Evidence specifically aimed at clarifying the effects of arrhythmia management on outcomes characteristic of aged people is completely lacking. In the elderly, the question regarding the effects of a rate- or a rhythm-control strategy of AF should be considered as an aspect of a more complex strategy, addressed to reduce disability and hospitalizations, and to improve quality of life and survival.


2021 ◽  
Author(s):  
Kyriaki-Nefeli D. Malamaki ◽  
Francisco Casado-Machado ◽  
Manuel Barragan-Villarejo ◽  
Andrei Mihai Gross ◽  
Georgios C. Kryonidis ◽  
...  

2005 ◽  
Author(s):  
Zongkai Yang ◽  
Xiaoliang Zhu ◽  
Xu Du ◽  
Wenqing Cheng ◽  
Tung Chou Chun

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