A technological battle burned hot between these two geniuses and their competing visions for the future of electricity.

In the last decade or so, significant advances have been made in the design of industrial power supplies and dc-dc converters, from the materials and device levels to size and weight reduction, thermal management, and package design. However, one often-overlooked category is protection of circuits and systems provided by the power supply and accompanying circuit breakers. These advances have contributed greatly to reliability and system availability while maintaining safety as well.

Combined, the electronics and “other” categories account for 15 percent of the average home total energy use, according to the Consumer Electronic Association2. Others like Greg Reed of the Power & Energy Initiative at the University of Pittsburgh suggest the number is closer to 20 percent.

Reed also predicts that by 2020 the number can reach 50 percent. This certainly is possible, if solid-state lighting is heavily adopted. Figure 1 shows that today’s lighting uses 12 percent of the home average energy. It is not likely that we will reach the full 12 percent as adopting solid-state lighting reduces the energy load from lighting.

So what about other household loads? Next in line are appliances. This category includes refrigerators, freezers, clothes washers, dryers, dishwashers, microwave ovens, cook tops, and ovens. Any appliances that use motors can switch to DC brushless motors.

Microwave energy is dominated by the magnetron, which is a DC-powered device.

The final categories are heating and cooling. If these systems are built from heat pump technology, then compressors and fans used for the condensers, evaporators, and circulating air can be brushless DC motors. This allows DC power to be used to provide higher energy efficiency.

Neither Edison nor Westinghouse, and not even Tesla, could have predicted that someday semiconductors would make AC-to-DC conversion easy and efficient.

So what are we waiting for? Well, we have considerable investment in our AC systems. However, more than 25 percent of the world lives off the grid. These homes easily could accept and benefit from a DC power source, such as solar panels.

These households could start out using solid state lighting and simple DC-powered fans. Additionally, DC energy could be stored in inexpensive battery systems. In many ways, homes starting from scratch will have the advantage of not having an AC legacy.

The DC-powered home most likely will need two DC buses. The “other,” electronics, and lighting categories could use a low-power DC bus, for example 12V to 48V. However, the heating, cooling, and appliances categories would benefit from a much higher voltage, for example 380V to 400V.

So what is it going to take to push the DC home into the mainstream for grid-connected homes? I think it will take a very well-defined benefit.

The response was a 30 percent energy savings. This was certainly a surprise.

We were thinking a 10 to 15 percent reduction would be attractive. Of course, it did depend on the cost to make the changes. The real answer was that they wanted a two-to-three year payback. At this point, we are not there yet.

The innovation developed by the Lappeenranta University of Technology “Low Voltage Equal Distribution System for Public Power Distribution” was awarded the Technology Prize by the Finnish Messrs Foundation. The prize for the first time is € 10,000. The award was announced today at the Technology 17 event opened at the Helsinki Fair Center.

Since 2005, Lappeenranta University of Technology has been researching a power distribution system based on low-voltage electricity (LVDC) in cooperation with industry. The aim has been to develop a more cost-effective way of replacing existing electricity distribution systems with renewable electricity distribution networks to meet future demands.

- As a result of the research, there is an innovation from active LVDC distribution, where the familiar energy of the history is connected to modern power electronics, network technology and information systems. LVDC’s business potential in Finland is € 40-60 million a year and its estimated global annual market potential is billions in billions, says Professor Jarmo Partanen.

- Innovation makes it possible to build electricity distribution networks at a lower cost, to improve the reliability of electricity distribution and the lack of security. In addition, similar technologies have many other applications, ships, real estate, electric car charging systems, said sales manager Marcus Bergström from the Exhibition Center as secretary of the prize drawer.

Source: http://www.etn.fi/index.php/13-news/6977-teknologia-palkinto-edullisemmalle-saehkoenjakelulle#ETNartikel

The war of the currents was fairly decisively won by AC. After all, whether you’ve got 110 V or 230 V coming out of your wall sockets, 50 Hz or 60 Hz, the whole world agrees that the frequency of oscillation should be strictly greater than zero. Technically, AC won out because of three intertwined facts. It was more economical to have a few big power plants rather than hundreds of thousands of tiny ones. This meant that power had to be transmitted over relatively long distances, which calls for higher voltages. And at the time, the AC transformer was the only way viable to step up and down voltages.

But that was then. We’re right now on the cusp of a power-generation revolution, at least if you believe the solar energy aficionados. And this means two things: local power that’s originally generated as DC. And that completely undoes two of the three factors in AC’s favor. (And efficient DC-DC converters kill the transformer.)

most devices these days use low-voltage DC, with the notable exception of some big appliances. Batteries store DC.

Resistive Heating

The problem with lower-voltage wiring is simple physics. For a given power demand, P=I*V, so a lower voltage means pushing more current.

That’s the reason that, for instance, power over Ethernet (PoE) schemes use around 48 V to transmit something like 30 W of power — those thin Ethernet cables can only carry so much current without wasting most of it away as heat. Even around 50 V, PoE schemes count on a loss of three to five watts in the cabling.

Safety

Electricity starts getting dangerous to humans somewhere around 30-50 V.
you’ve got 110 or 230 V AC in your walls right now

Which is to say that although sub-30 V DC would be safer, we suspect that the safety will be designed into the connectors, or into circuit breakers.

Switches and Relays

Which brings us to the last concern. Have you ever arc welded? How much DC voltage does it take to strike up an arc? Something in the neighborhood of 24 V is a pretty common value for a professional unit, but people have been able to weld with 20 V tool battery packs or even 12 V car batteries.

Switches and Relays

Which brings us to the last concern. Have you ever arc welded? How much DC voltage does it take to strike up an arc? Something in the neighborhood of 24 V is a pretty common value for a professional unit, but people have been able to weld with 20 V tool battery packs or even 12 V car batteries.

Making mechanical switches that work for your DC home electric system is going to be a problem

The X factor here is progress in MOSFET or IGBT manufacture. Solid state DC circuit breakers aren’t as cheap as mechanical (AC) breakers yet, but at voltages like we’re considering inside the home, they’re getting there.

Whether this goes from the panel to the battery to the plug at 48 V or 12 V is going to depend on the relative prices of copper and hefty FETs, but we’re betting that FETs get cheaper and copper more expensive. We’d personally like to see this relatively high voltage stepped down at the plug for safety, say to 12 V, but we won’t quibble. It would make the perfect complement to our existing AC infrastructure.

He focused in particular on the necessary DC power distribution, power electronics efficiency calculation. The results will benefit future smart grid planning.

Over a hundred years ago, instead of Edison developed DC power supply stabilized for use in AC power distribution. The reason was that the produced electricity is inherently synchronous generators for electricity exchange and the exchange of alternating current voltage level of the transformer is simple.

The smart grid of the future management of the exchange will, however, be even more challenging. Rekola that decentralized electricity production increased, the distribution of the uncertainty increases.

- The use of DC electricity would facilitate the future of the so-called smart grid management, improve customer power quality and reduce customer has experienced electricity outages, says Rekola.

DC Power Distribution was found technically functional Lappeenranta University of Technology, as well as the Suur-Savo electricity together through pilot equipment. However, the introduction of the Equal Distribution of large-scale conditional on the acquisition and evaluation of operating costs. As a result, Rekola focused her doctoral dissertation balanced distribution of electricity needed for the analysis of power electronic commercial relations. The result was simulation models for DC and inverters, as well as the filters needed to calculate the loss of their context.

Power electronics is a very high efficiency at rated output, but decreases at low power. The challenge gender distribution of electricity is that consumers’ energy consumption fluctuates over a wide power range and has most of the time very small compared to the instantaneous maximum load. In addition, the integration of power electronics and the current power grid security benefit point of view is challenging.

Dissertation in the field of Rekola Electrical Energy ”Pienjännitetasasähkönjakelun hyötysuhteeseen vaikuttavat tekijät tehoelektroniikan näkökulmasta” (“Factors affecting the efficiency of the low-voltage DC electricity distribution power electronics perspective”), checked the information and the Faculty of Electrical Engineering Tampere University of Technology next Friday.

Source: http://etn.fi/index.php?option=com_content&view=article&id=3617:osa-sahkosta-voitaisiin-jakaa-tasasahkona&catid=13&Itemid=101

The International Electrotechnical Commission (IEC) has created a normal for a configuration of plugs and socket-outlets for family and alike motives in secured and mobile applications. Extra-low voltage|Safety extra-low voltage (SELV) plugs and socket-outlets for 16 amps and 6, 12, 24, either 48 volts Alternating Current|AC and Direct Current|DC. For employ whichever inside either out-of-doors.

IEC 60906-3:1994
https://webstore.iec.ch/publication/3884

IEC System of plugs and socket-outlets for household and similar purposes – Part 3: SELV plugs and socket-outlets, 16 A 6V, 12 V, 24 V, 48 V, a.c. and d.c.

A DC connector (or DC plug, for one common type of connector) is an electrical connector for supplying direct current (DC) power.

Compared to domestic AC power plugs and sockets, DC connectors have many more standard types that are not interchangeable. The dimensions and arrangement of DC connectors can be chosen to prevent accidental interconnection of incompatible sources and loads. Types vary from small coaxial connectors used to power portable electronic devices from AC adapters, to connectors used for automotive accessories and for battery packs in portable equipment.

Small cylindrical connectors come in a variety of sizes. They may be known as “coaxial power connectors”, “barrel connectors”, “concentric barrel connectors” or “tip connectors”.

The intended use of these plugs is on the cable connected to a power supply.

IEC 60906-3:1994

The International Electrotechnical Commission (IEC) has produced a standard for a system of plugs and socket-outlets for household and similar purposes in fixed and portable applications. Safety extra-low voltage (SELV) plugs and socket-outlets for 16 amps and 6, 12, 24, or 48 volts AC and DC. For use either indoors or outdoors

In the broadcast, film and television industries, the 4-pin XLR connector is the standard for 12 V power. The connectors are wired pin 1 negative, pin 4 positive. Often pins 1 and 2 will be negative, 3 and 4 positive for a higher current rating. Female connectors are used as supply and male connectors are used on loads.

In Australia, a T-configuration Clipsal socket is used for extra-low voltage DC power outlets, such as in stand-alone power systems (SAPS) or on boats, in order to prevent accidental connections of 12 V appliances into 240 V socket-outlets.

Due to the popularity of USB for mobile phones and tablets, USB sockets and plugs have become a common choice for other small devices that require five volts or less, even those that require no data connection.

DC connector
From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/DC_connector