In the past ten years, LLC resonant converters have become a mainstream topology for dc/dc power conversion, and multiple design tools have been developed for this topology, including controllers, regulators, soft-switching techniques, etc. While many tools are available for designing this converter, techniques for accurately determining power losses in the inverter mosfets of the topology based on time-domain analysis have not been fully explored yet. Precise power loss estimation is fundamental to determine the thermal behavior of the switches before the converter is built, which accelerates and optimizes the thermal management design process. In addition, accurate methods of estimating conduction losses, which are dominant in this topology, switching losses, and body diode losses are lacking in the literature. This paper proposes a method for enhancing power loss estimation in LLC inverter mosfets based on time-domain analysis of the converter. Moreover, a detailed characterization of mosfet's conduction losses ($P_{\text{cond}}$), switching losses ($P_{\text{sw}}$), and body diode losses ($P_{\text{diode}}$), including the effects of different parameters such as gate-source voltage ($V_{\text{GS}}$), junction temperature ($T_{j}$), drain current ($\displaystyle I_{D}$), and drain-source voltage ($V_{\text{DS}}$), is presented, which can further improve power loss assessment in this topology. The developed method based on time interval analysis replaces the simplistic first-harmonic approximation (FHA), which allows for improved power loss calculations. Further improvement is obtained with the detailed characterization of the switching device. As verified by simulation and experimental results, the proposed estimation tool provides a significant boost in accuracy for power loss determination when compared to the existing method for power loss estimation using FHA.
We derive a Doi-Peliti field theory for free active Ornstein-Uhlenbeck particles, or, equivalently, free inertial Brownian particles, and present a way to diagonalise the Gaussian part of the action and calculate the propagator. Unlike previous course-grained approaches this formulation correctly tracks particle identity and yet can easily be expanded to include potentials and arbitrary reactions.
Supplemental Digital Content is Available in the Text. Abstract Allard, P, Martinez, R, Deguire, S, and Tremblay, J. In-season session training load relative to match load in professional ice hockey. J Strength Cond Res 36(2): 486–492, 2022—The aim of this study was to describe match load and intensity across player positions and match periods, the distribution of pregame training load and intensity over training days before a match, by player position, and the cumulative weekly training load over a season. Fifty professional ice hockey players, which at one time or another were part of the roster for the Laval Rocket during the 2017-18 season of the American Hockey League, participated in this study. External load was monitored in every training session and match over the season using portable inertial measurement units. Data are reported in absolute and relative values to a match. Defensemen have a lower intensity during matches than forwards (−1.70 OIL·min−1) while load is similar across position. The first period shows a higher relative load (+5.28% relative on-ice load [OIL]) while the third has a lower relative intensity (−2.91% OIL·min−1). Defensemen seem to train at a systematic higher relative intensity than wingers and centers (+8.34% relative OIL·min−1). Finally, the weekly training load remains relatively constant throughout the season (equivalent of 3.56 ± 1.69 matches played per week). Our results support the need for player monitoring in ice hockey using an individualized approach.
Jesualdo Cuevas-Aburto, Ivan Jukic, L. Chirosa-Ríos
et al.
Abstract Cuevas-Aburto, J, Jukic, I, Chirosa-Ríos, LJ, González-Hernández, JM, Janicijevic, D, Barboza-González, P, Guede-Rojas, F, and García-Ramos, A. Effect of traditional, cluster, and rest redistribution set configurations on neuromuscular and perceptual responses during strength-oriented resistance training. J Strength Cond Res 36(6): 1490–1497, 2022—This study aimed to compare the acute effect of traditional (TR), cluster (CL), and rest redistribution (RR) set configurations on neuromuscular and perceptual measures of fatigue. Thirty-one resistance-trained men randomly performed a Control session and 3 experimental sessions consisting of the squat (SQ) and bench press (BP) exercises performed against the 10 repetition maximum load using TR (3 sets of 6 repetitions; 3 minutes of interset rest), CL (3 sets of 6 repetitions; 30 seconds of intraset rest every 2 repetitions; 3 minutes of interset rest), and RR (9 sets of 2 repetitions; 45 seconds of interset rest) set configurations. A significant effect of “set configuration” (p = 0.002) was observed for barbell velocity. The average velocity of the training session was lower for TR compared with CL (% difference = 5.09% in SQ and 5.68% in BP) and RR (% difference = 5.92% in SQ and 2.71% in BP). The 3 set configurations induced comparable decrements in countermovement jump height (% difference from −6.0% to −8.1%) and throwing velocity (% difference from −0.6% to −1.2%). Ratings of perceived exertion (RPE-10) values collected after the sets were higher for TR (SQ: 6.9 ± 0.7 a.u.; BP: 6.8 ± 0.8 a.u.) compared with CL (SQ: 6.2 ± 0.8 a.u.; BP: 6.4 ± 0.7 a.u.) and RR (SQ: 6.2 ± 0.8 a.u.; BP: 6.6 ± 0.9 a.u.), while the session RPE did not differ between the set configurations (p = 0.595). CL and RR set configurations allow for higher velocities and lower RPE values during resistance training sessions not performed to failure in comparison with a TR set configuration.
Ryan M. Curtis, R. Huggins, David P. Looney
et al.
Abstract Curtis, RM, Huggins, RA, Looney, DP, West, CA, Fortunati, A, Fontaine, GJ, and Casa, DJ. Match demands of National Collegiate Athletic Association Division I men's soccer. J Strength Cond Res 32(10): 2907–2917, 2018—This study aimed to profile positional movement characteristics of National Collegiate Athletic Association (NCAA) Division I male soccer players. Eighteen Division I male soccer players were monitored using global positioning systems, inertial movement, and heart rate (HR) technology during 24 matches over a full competitive season (N = 235 observations). Positional groups were classified as either a forward (F), center midfielder (CM), wide midfielder (WM), or defender (D). Movement was profiled by locomotor (walking [0–7.19 km·h−1], jogging [7.20–14.39 km·h−1], running [14.40–21.59 km·h−1], and sprinting [>21.6 km·h−1]), and acceleration/deceleration characteristics (low intensity [0–1.99 m·s2], moderate intensity [2–3.99 m·s2], and high intensity [>4 m·s2]). Players averaged distances of 9,367 ± 2,149 m per match at speeds of 91 ± 20 m·min−1 and physiological intensities of 78 ± 8 %HRmax. Center midfielder demonstrated the highest average speeds (97 ± 20 m·min−1) and covered the most distance (9,941 ± 2,140 m). Wide midfielder accumulated the most sprint distance (391 ± 145 m) and high-intensity accelerations (129 ± 30 n)/decelerations (96 ± 24 n). Several practically meaningful differences exist between positions for internal and external load metrics. Match loads seen in NCAA Division I soccer vary from reports of professional soccer; however, the effects of match regulation, structure, and congestion, which are unique to NCAA soccer, require further investigation. Physical and physiological load monitoring of NCAA soccer may aid coaches and practitioners in the periodization of training programs leading up to and during a competitive soccer season. These data speak to the necessity for examining both internal and external loads by position.
Living things avoid equilibrium using molecular machines. Such microscopic soft-matter objects encounter relatively large friction and fluctuations. We discuss design principles for effective molecular machine operation in this unfamiliar context.
We study general stochastic birth and death processes including delay. We develop several approaches for the analytical treatment of these non-Markovian systems, valid, not only for constant delays, but also for stochastic delays with arbitrary probability distributions. The interplay between stochasticity and delay and, in particular, the effects of delay in the fluctuations and time correlations are discussed.