Passive power line communication device and method

Abstract

The present invention relates to the field of transferring information over the power line to and/or from the device or devices powered by said power line. Devices that may be powered by either alternating current (AC) or direct current (DC) their operation may be controlled by which type of power they are receiving, AC, +DC or −DC. Data may also transmitted by alternating the polarity of each half cycle of the power line, on a one half by one half cycle basis, in a controlled manner such that the powered device may receive such data to control its mode of operation. A method of reducing the heat in the switching devices and a system of encoding the data such that each powered device may have a different address and therefore may return data when requested is also disclosed.

1 . A device for connection to a power line that communication system for connection to a source of alternating current and voltage operable to supply power to and communicate with one or more powered devices comprising: 
 means for converting for selecting source of alternating current and voltage for converting said source of alternating current and voltage to direct current and voltage;    circuitry for selecting the polarity, either positive or negative, of the output of said assemblage of components consisting of four diodes connected in a bridge configuration the output of which is connected to of four switching devices interconnected in the manner of a full bridge with the first and second switching device connected in series across the output of the four diode bridge configuration, the third and forth switching devices connected also in series across said four diode bridge configuration with the output of said full bridge configuration being between the junction of said first and second switching device as one terminal and the junction of said third and forth switching devices as the second terminal; and    a controlling means connected to each of the four switching devices comprising said full bridge configuration said controlling means synchronized with the source of alternating current and voltage is such a manner as to cause said switching devices to switch on and off at or near the zero crossing point of the source of alternating current and voltage such as to supply individual half cycles, either positive or negative as required, at twice the frequency of the source of alternating current and voltage to said one or more powered devices.    
   
   
       2 . The power source and data communication system of  claim 1  wherein said switching devices are bi polar transistors.  
   
   
       3 . The power source and data communication system of  claim 1  wherein said switching devices are field effect transistors.  
   
   
       4 . The power source and data communication system of  claim 1  wherein said switching devices are silicone controlled rectifiers.  
   
   
       5 . The power source and data communication system of  claim 1  wherein said switching devices are gate turn off controlled rectifiers.  
   
   
       6 . The power source and data communication system of  claim 1  wherein an extremely low impedance switching device is connected across said assemblage of components connected to said source of alternating current and voltage for converting said source of alternating current and voltage to direct current and voltage, said extremely low impedance switching device connected to said controlling means which causes it to conduct when conventional alternating current and voltage power is to be supplied to said one or more powered devices and to be non conductive when half cycles of direct current are supplied to said powered devices to relieve said means for converting said source of alternating current and voltage to direct current and voltage from conducting any current during said period.  
   
   
       7 . A power source and data communication system for connection to a source of alternating current and voltage operable to supply power to and communicate with one or more powered devices comprising: 
 a assemblage of components connected to said source of alternating current and voltage for converting said source of alternating current and voltage to half cycle sinusoidal pulses of either polarity as a source of power for said one or more powered devices;    a means for communicating with said one or more powered devices where individual half cycles of the power line frequency represent digital data bits with one polarity of half cycle pulse representing a zero bit and the opposite polarity representing a one bit.    
   
   
       8 . A power source and data communication system of  claim 7  wherein a digital data bit is recognized as valid only when two or more half cycle pulses of the same polarity occur one immediately after the other.  
   
   
       9 . A power source and data communication system of  claim 8  wherein two complete cycles of the AC line power represent the beginning or start of a code sequence.  
   
   
       10 . A power source and data communication system of  claim 7  wherein the zero and one bits are assembled into a series of bits comprising a code sequence with each code sequence having a grouping of bits indicating the address of one of the said powered devices with the balance of the bits in said code sequence comprising instructions to the powered device whose address is contained in the grouping of bits indicating the which power device is being addressed.  
   
   
       11 . A power source and data communication system of  claim 9  wherein the code sequence contains a designated space within its sequence of data bits within said code sequence where the addressed powered device can place a signal of a frequency sufficiently higher then the power line frequency as a means of communicating data feedback from said addressed powered device to the assemblage of components connected to said source of alternating current and voltage.  
   
   
       12 . A power source and data communication system of  claim 9  wherein certain of the data bits within the code sequence are recognized by all the powered devices whether or not that powered device has been addressed to provide for commands universal to all power devices.