Taming the Load Current of Identical Cells in Matrix

2021 ◽  
Vol 03 (04) ◽  
Author(s):  
Seok-In Hong

We explore the load current [Formula: see text] for a rectangular array (matrix) of [Formula: see text] identical cells where [Formula: see text] strings (columns) of [Formula: see text] serial cells (rows) are arrayed in parallel. [Formula: see text] is equal to [Formula: see text] with the internal resistance of the cell and the load resistance exchanged. By treating a linear fractional function as a translated inversely-proportional function, we can easily capture the properties of [Formula: see text] and the relative magnitude of [Formula: see text] and [Formula: see text] via their ratio. The limiting behaviors of the load current are discussed beyond the ideal-cell and short-circuit limits. For the given total number of cells, we graphically verify the recent findings on the matrix of cells that produces the maximum load current. Finally, we analyze the possibility of a car starting with lemon cells or AA dry cells in matrix. This work would be useful in creating a high school or university curriculum that unifies identical cells in series, parallel, or matrix.

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Hsiung-Cheng Lin ◽  
Heng-Chuan Zo ◽  
Bo-Rong He

Electronic breakers or fuses are most widely used tools to protect the electric-driven facilities from overload or short circuit. However, they may suffer from two major drawbacks: (1) it normally takes more than 0.1 s to react, resulting in facilities not sufficiently protected, and (2) a higher rating size of breakers or fuses is demanded than expected due to lack of a surge current suppression mechanism. To overcome these problems, this paper proposes a fast large current electronic breaker based on the integration of current divider sensing and surge suppressing methods. The load surge current can be effectively suppressed by series negative temperature coefficient (NTC) thermistors. The load current is then divided into a small portion and converted to a voltage signal for amplification and comparison with the predefined threshold value, i.e., the maximum load tolerance current. AC power will be disconnected immediately by the switching circuit once the load current exceeds the tolerance value. The disconnection of power supply will continue for a period of time set by the timer. The experimental results verify that the proposed electronic breaker can provide a large load current protection up to 20 A under effective surge suppression within 10 ms.


2021 ◽  
Vol 3 (2) ◽  
pp. 16-18
Author(s):  
Sergey A. Gerasimov

Liquid in contact with two asymmetrical spiral-shape aluminum electrodes behaves like a still weak source of electrical energy. Almost the only way to increase the efficiency of such a source of electrical energy is to reduce internal resistance. Reducing internal resistance is equivalent to using multiple sources of electrical energy connected in series or in parallel. To check this for such unusual sources it is first necessary to study the properties of each source, which is the voltage drop across the load resistance and the internal resistance of each source. Detailed analysis of experimental data shows that the process of forming the dark current is different from a chemical one.


1987 ◽  
Vol 19 (12) ◽  
pp. 47-53 ◽  
Author(s):  
J. A. Oleszkiewicz ◽  
A. B. Sparling

Severe climate, intermittent rivers and availability of land make facultative lagoon systems the method of choice in treating primarily domestic sewage from smaller municipalities. The lagoons are designed on a recommended maximum load of 55 kgBOD5/ha d to first cell, while the second cell provides storage. The discharge is twice annually and the occurrence of the spring ice break-up odor period is one of the primary criteria limiting this load. Based on full scale performance data, it is demonstrated that, from the standpoint of odor nuisance, the load to the first cell should be kept equal to or less than 35 kg/ha d. Full scale studies of an overloaded lagoon system show the futility of under-ice aeration for odor control. Mechanism of natural odor control during ice break up is elucidated. Upgrading of the overloaded systems or lagoons receiving significant industrial contribution is best achieved by construction of a 3–5 m deep aerated lagoon preceding the two or more facultative cells in series.


2020 ◽  
Vol 178 ◽  
pp. 01060
Author(s):  
A V Kuznetsov ◽  
D S Aleksandrov ◽  
Y P Yurenkov

This paper shows that successful switching of extremely high short-circuit currents I> 50 kA can be achieved by joint operation of a liquid-metal self-resetting current limiter and a circuit breaker connected in series. The type NFU-225 device from Mitsubishi was taken as an example. The time-current characteristic of joint operation of a liquid-metal self-resetting current-limiting device and a circuit breaker was compiled. However, further in the article physical processes occurring in a liquid-metal self-resetting current limiter with a complete transformation of fusible unit are considered. The result of work is modelling of operation of liquid-metal fuses when overcurrents are switched off based on the pilot studies obtained by the Japanese scientists. It is proposed to simulate the break process not at every time moment, but at specific time moments (reference points). At other time moments, current and voltage should be considered as approximately linearly changing characteristics. The work of current limiter can be represented by three stages: the pre-arc, the main arc and the final arc. If the current density is less than 1000 A/mm2, then the pre-arc operation stage of the current limiter includes the following sections for heating the fusible unit: primary heating to the melting temperature; melting and its transition to liquid state; secondary heating to evaporation temperature; evaporation of fusible unit.


2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Janez Puhan ◽  
Dušan Raič ◽  
Tadej Tuma ◽  
Árpád Bűrmen

A modified static CMOS inverter with two inputs and two outputs is proposed to reduce short-circuit current in order to increment delay and reduce power overhead where slow operation is required. The circuit is based on bidirectional delay element connected in series with the PMOS and NMOS switching transistors. It provides differences in the dynamic response so that the direct-path current in the next stage is reduced. The switching transistors are never ON at the same time. Characteristics of various delay element implementations are presented and verified by circuit simulations. Global optimization procedure is used to obtain the most power-efficient transistor sizing. The performance of the modified CMOS inverter chain is compared to standard implementation for various delays. The energy (charge) per delay is reduced up to 40%. The use of the proposed delay element is demonstrated by implementing a low-power delay line and a leading-edge detector cell.


2013 ◽  
Vol 2013 ◽  
pp. 1-6
Author(s):  
M. Waegner ◽  
A. Finn ◽  
G. Suchaneck ◽  
G. Gerlach ◽  
L. M. Eng

We describe the fabrication of lead zirconate titanate (PZT) nanodisc arrays isolated by a polymer layer and contacted with a top electrode. PZT thin films were deposited by multitarget sputtering onto a platinum/titanium bottom electrode and structured by means of nanosphere lithography. To guarantee short-circuit-free deposition of a top electrode, the space between the nanostructures was filled by a polymer. Two approaches for the filling are demonstrated: (a) imprinting and (b) skim coating. Single nanodiscs embedded in a flexible polymer matrix have two major advantages. First, taking into account the flexibility of the matrix, they can vibrate in lateral direction and, second, due to shrinking to the nanoscale, predominant directions of the polarization form, such as vortex- or bubble-like domain patterns. Piezoresponse force microscopy was performed on patterned and nonpatterned samples with and without a top electrode to check the local piezoresponse. Comparison of the different samples revealed an increase in lateral piezoactivity for patterned samples with Ni/Cr electrode while the out-of-plane piezoresponse remained constant. Gold electrodes limit the piezoresponse in both measured directions.


1988 ◽  
Vol 255 (2) ◽  
pp. G247-G252 ◽  
Author(s):  
A. N. Charney ◽  
J. I. Scheide ◽  
P. M. Ingrassia ◽  
J. A. Zadunaisky

Chloride absorption in the small intestine of the winter flounder, Pseudopleuronectes americanus, is reported to be sensitive to ambient pH. We studied this sensitivity in isolated stripped intestinal mucosa mounted in modified Ussing chambers. Unidirectional 36Cl fluxes (JClm----s, JCls----m) were measured under short-circuited conditions in bathing solutions containing various combinations of HCO3- (0-20 mM), partial pressure of CO2 (0-36 mmHg), and pH (6.77-7.85). We found that JClm----s, net 36Cl flux (JClnet), and short-circuit current (Isc) increased and JCls----m decreased predominately in response to increases in bathing solution pH. There was a linear relationship between pH and both JClnet (r = 0.92, P less than 0.01) and Isc (r = 0.96, P less than 0.005) between pH 6.77 and 7.74. The pH effect was completely reversible, did not require either CO2 or HCO3-, and was not affected by the presence of mucosal barium at 1 mM. Mucosal bumetanide (0.1 mM) completely inhibited the pH effect. These data suggest that the process by which Cl- is absorbed in the flounder intestine is sensitive to pH. The data do not indicate whether pH affects Na+-K+-2Cl- cotransport or a Cl- transport pathway in series with this process. The direction of Cl- absorption in response to pH contrasts with inverse relation of pH and Cl- absorption in mammalian small intestine.


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