AC-DC buck-type power factor correction (PFC) converters, with their step-down output voltage capabilities, can serve as promising prestage solutions, enabling end users to operate under relatively ...low voltage conditions. However, most stat-of-the-art buck-type PFC converters do not set outputs to 160 V or higher due to the concerns about poor power factor (PF) caused by input current dead zones (DZs). This restricted output voltage set limits the buck-type PFC converter applications. Thus, this article proposes a family of hybrid cell-based buck-type bridgeless topologies, derived by combining buck cell with flyback, boost, and buck-boost cells. This combination narrows the input current DZs, enabling a higher output voltage and thus broadening the applications. The proposed topology family with 20 derived topologies is reviewed and analyzed for a comprehensive investigation. Then, a specific topology with high PF and relatively high efficiency is studied. The input PF, output ripple, inductor boundary, control method, and power loss analysis are presented. Experimental tests of the studied topology and performance comparisons with the prior-art bridgeless buck and bridgeless buck-boost PFC converters are conducted to verify the topology feasibility and distinguishing performances.
A low-power cache has become essential in many applications, but cache accesses contribute significantly to a chip's total power consumption. Because most bit values read from the cache are 0's, the ...authors introduce a dynamic zero-sensitivity (DZS) scheme that reduces average cache power consumption by preventing bitlines from discharging in reading a 0.
Poseban problem u hrvatskim demografskim istraživanjima čine metodološka neujednačenost i upitnost službenih podataka na više razina. Ovaj problem ne čini samo puko administrativno pitanje nego ...postoje i stvarne negativne posljedice koje se mogu očitovati u zlouporabama socijalnoga, zdravstvenoga i poreznoga sustava, ali i u stvaranju prepreka pri donošenju odgovarajućih demograf- skih revitalizacijskih mjera. Potreba razvijanja dodatne pomoćne metode procjene broja stanovnika u Hrvatskoj proizlazi i iz pred- stavljene metodologije popisa stanovništva 2021. godine koja nije uklonila mogućnost prijave „fiktivnoga stanovništva“. Metoda po- drazumijeva praćenje potrošnje vode u kućanstvima u pet slavon- skih županija u razdoblju od 2011. do 2019. godine. Rezultati metode pokazuju pouzdane uvide o smanjenju broja stanovnika. U razdoblju od 2011. do 2019. godine svih pet slavonskih župa- nije ima pad broja stanovnika od 7,37 % do 8,37 %, a trend je osobito pojačan nakon ulaska Hrvatske u EU. U ovome je raz- doblju populacija istočne Hrvatske prirodnim kretanjem i iselja- vanjem smanjena za 105 698 građana, što čini 8,7 % ukupnoga stanovništva Slavonije.
This paper focused on the performance analysis of two induction motor drive fed by the Five Leg Inverter (FLI). Two carrier based PWM scheme for FLI are used in these motor control analysis which are ...known as Double Zero Sequence (DZS) Injection Method and Two Arm Modulation (TAM). Simulink/MATLAB is used as the simulation tool for analysis. Detailed investigation of the speed response characteristics under speed command change, load disturbance, steady state stability and dynamic response is performed based on these two schemes. The results reveal that both methods have good capabilities of independently controlling the two motors. Comparison of these methods show that, DZS method has better speed and torque ripple disturbance performance at half rated speed while TAM have better performance at lower rated speed. Further analysis for the same speed demand shows that TAM has better capability for a higher same speed operation range.
Many applications use two or more motors operating in parallel configuration by using one variable speed drive. This system is able to control these multiple motors at the same desired motor speed ...operation which provide advantages in terms of components and cost reduction. However, the system is not able to control each motor separately if it is desired to operate at different speeds and it also cannot withstand the load disturbance. To address this problem, the design of combined Vector Control-Direct Torque Control (DTC) methods is proposed and their performance is investigated for the case of independent controlled two induction motors fed by single Five Leg Inverter (FLI) method. Double Zero Sequence (DZS) Injection Method Space Vector Pulse Width Modulation (SVPWM) scheme is used for the FLI. Simulation results from the Simulink/Matlab that verify the validity of the method are also included. The results show the ability of the proposed method to control motor speed independently under forward-reverse step speed command and load disturbance condition.
Intenzivna harmonizacija i standardizacija poslovnih i informacijskih procesa s europskim institucijama predstavlja izazov središnjem tijelu službene statistike Republike Hrvatske, Državnom zavodu za ...statistiku, ali i obvezu jer su uredbe i direktive EU u pravilu obligatorne te praktički imaju pravo prvenstva u odnosu na redovne poslove. S druge strane, Eurostat i nacionalne statistike zemalja EU (naročito Skandinavske zemlje) rade s naprednim tehnologijama i rapidno uvode nove standarde, aplikacije, integrirane informacijske sustave i slično. Tehnologija se prvenstveno bazira na XML rješenjima koja omogućuju standardiziranu reprezentaciju setova podataka, koje u takvom obliku mogu primati i slati različiti portali što znatno ubrzava i pojednostavljuje kolaboraciju i komunikaciju. U takvoj situaciji, pitanja koja se nameću u DZS-u su: kako nam upravljanje znanjem može pomoći da odgovorimo izazovima uvođenja novih tehnologija i usklađivanju poslovnih procesa sa standardima Eurostata? Kako se znanje u DZS-u kreira, kako se koristi? U kojoj mjeri se dokumentira i na koje načine se prenosi? Koje su barijere prenošenju znanja? Postoji li potreba za razvojem strategije upravljanja znanjem? Pretpostavljamo da se počne uvoditi sustavni proces upravljanja znanjem da bi se unaprijedila komunikacija i kooperacija, promijenila kultura organizacije, u većoj mjeri bi se znanje dokumentiralo, čime bi se u konačnici poboljšale performanse organizacije. Polazna točka analize stanja bio bi Sektor informatičkih tehnologija jer je shvaćen kao potporanj ostalim sektorima u DZS-u zbog pružanja svih informatičkih usluga i servisa. Također, IT sektor osigurava i informacijsku tehnologiju za konceptualnu i praktičku implementaciju procesa upravljanja znanjem.
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