DCplc – brainstorming

ANSARI's DC-Power Line Communication design approach (DCplc)

» Posted on 21. Dec 2011

 

 Is it possible to realize a small reliable PLC-interface on a dc-power line to broadcast audio and transmit bidirectional data at the same time? 

 

Introduction

In today’s life the amount of consumed electrical energy is getting more and more important. Controlling power consumption is getting on one side economically driven and on the other side it is falling socially into weight.

With this fact in mind, we want to introduce and start designs covering all the needs detected for economical driven devices fulfilling feature reach capabilities for future everyday life.

Some Facts

Any device used in our daily life needs first of all a power source. Many of the tasks covered by them are realized using voltages below 48V. In fact there are billions of devices, which first have to convert the 110V/220V power to some few volts (≤48V) to function. There is no force to use always 110V or 220V based systems in our environment.

Each down- or up- converting of power supply means a little bit lost of energy!

If locally generated “green” power is not needed to be up-converted, or the number of down converting power supplies are reduced by using low power devices connected to one down-converter, especially helpful for devices running in standby modes, we can save a huge amount of wasted electrical energy.

48V seems to be a magic voltage level in future designs. Many of limiting norms and standards about using electrical power are for systems running above 48V. So why don’t we define a 48V system bypassing many of not only standards but also technical limits?

It is common in today’s electric installations to separate power segments based on their function and area (like lightening, plugs, oven, ground floor, corridor , etc.) and back-fuse them by mechanical fuse-switches at a central location. So we should easily be able to accept having 48V segments in parallel for low power enabled devices. Practically any device, which includes a power supply, converting the main power down to another running voltage is a candidate to be connected in a same way to the 48V segment as done before by connecting it to the main power plug.

A more welcome definition would be, if devices connected to a power segment could operate as known no matter if the segment is driven by low voltage  (≤48Vdc) or 110Vac/220Vac! The capability of switching between the two systems, while connected devices are running, would bring up huge advantages at the end in controlling electrical power consumption.

Basic Design Approaches

Based on all pointed issues above, we would like to point out some contours for our future designs:

  1. Power line voltage is a segment based definition and may be in the range of 12V to 48V DC, or the existing 90Vac to 240Vac power ranges used in today’s life. So the central switch and fuse cabinet can be redefined to be the central node of all power segments in an installation, which is controlled and monitored as needed and hosts optional PLC data communication master nodes for each segment.  
  2. At least each low voltage segment supports over the same power line wires a bidirectional data streaming, which allows exchange of data between the devices on the same segment. Normal 110V/220V power segments may also be upgraded with PLC capability to realize a full controllable electrical installation.
  3. On one power segment, communication groups and data directions should be based on frequency multiplexing techniques.
  4. Multi-source devices, which can operate in 90Vac … 240Vac and 48V systems automatically over same plug will be of high interest in many cases.
  5. DC powered segments may contain multiple power sources at the same time (batteries, solar panels, main power down-converters). Energy delivery from which source may be prioritized just by defining slightly different voltage levels automatically. 
  6. One-Way audio broadcasting from a master to multiple slaves and bidirectional data packet transfers at the same time on a power segment are minimum capabilities of a DC power line communication (DCplc).
  7. A powerful special DC segment feature is the option to run the segment by green energy sources like solar panels while the alternative power source is available and automatically switch back to legacy 110V/220V system, when the green power source is unavailable or exhausted as long as all devices on the segment are multi-source capable as described above.
     

 

Implementation

Basic functional components for a first design is given by other post explained on this web site. Beside some minor integration designs the major blocks for controlling and communication can be covered by discussed points in PLC – BrainstormingComLinkB and EMU1node – Carrier Board posts. As a result a new Carrier board can be defined to host the ComLinkB with the focus to interface 110V/220V and DC low voltage sources, enabling the desired communication on the power line.

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