Claims
- 1. A power line communications (PLC) system including a power line, an electrical motor having a set of windings, a power supply for powering the motor, a transmitter, and a receiver, said transmitter being operable to transmit information to the receiver on a power signal by modulating a leakage current between two turns of the set of motor windings.
- 2. A PLC system according to claim 1, wherein the at least one characteristic altered is any one of resistance, inductance and/or capacitance.
- 3. A PLC system according to claim 1, wherein multiple transmitters are used with each transmitter using a different modulation technique.
- 4. A PLC system according to claim 1, wherein multiple transmitters are used with each transmitter using the same modulation technique, but each having different modulation modes within that technique.
- 5. A PLC system according to claim 1, wherein the modulation is effected by an amplitude modulation technique.
- 6. A PLC system according to claim 5, further comprising an inductive electrical load (IEL) powered by said power supply wherein the amplitude modulation technique modulates the characteristics of the IEL such that changes in amplitude of the power flow, current or voltage can be detected.
- 7. A PLC system according to claim 1, wherein the receiver is able to filter out and recover the transmitted information.
- 8. A PLC system according to claim 1, further comprising an inductive electrical load (IEL) powered by said power supply wherein the transmitted information is contained within a sequence of modulations from the transmitter which are de-modulated and reconstructed by the receiver to recover a fully transmitted message.
- 9. A PLC system according to claim 8, wherein multiple consecutive or concurrent modulations occur in the same positive or negative half of current flow to the IEL.
- 10. A PLC system according to claim 1, wherein a current flow through a modulated impedance is not rectified to provide modulated power flow in both positive and negative half-cycles of a current flow to the IEL.
- 11. A PLC system according to claim 1, wherein a current detection circuit is used to determine a zero crossing of a current flow to an IEL in order that the modulation is activated only at pre-determined points of current flow.
- 12. A PLC system according to claim 1, wherein a modulation time period is limited to a known pre-set value to reduce power loss within the modulation circuit.
- 13. A PLC system according to claim 1, wherein the modulation is controlled by temperature and power losses within the modulation circuit.
- 14. A PLC system according to claim 1, wherein a modulation time period is triggered to occur only at times of reduced current flow to the motor by reducing power loss within the modulation circuit.
- 15. A PLC system according to claim 1, wherein a modulation time period is triggered to occur only at times of reduced voltage applied to an IEL thereby reducing power loss within the modulation circuit.
- 16. A PLC system according to claim 1, wherein the transmitter includes a circuit similar to the receiver to provide feedback on background noise at the modulation mode wherein the transmitter will actively alter a modulation technique or mode.
- 17. A PLC system according to claim 1, wherein the receiver includes a circuit to sweep modulation modes in order to detect if the transmitter has modified the modulation modes in order to increase signal to noise ratio.
- 18. A PLC system according to claim 1, further comprising a voltage detection circuit to determine a zero crossing of voltage applied to an IEL in order that modulations are activated only at fixed periods on a voltage waveform.
- 19. A PLC system as claimed in claim 1 wherein the two turns are in a single phase of the set of windings.
- 20. A PLC system as claimed in claim 1 wherein turns are selected close to the null point of the motor.
- 21. A PLC system as claimed in claim 1 wherein a proportion of total turns between the said two turns is selected in order to achieve a predetermined signal to noise ratio.
- 22. A PLC system according to claim 1, wherein the power flow supply is constant.
- 23. A PLC system according to claim 1, wherein a current flow through a modulated impedance is rectified to only provide modulated power flow in one half-cycle of the current flow to the motor.
- 24. A PLC system according to claim 1, wherein said system functions as an over-temperature system in a pump used for mine, sump and quarry de-watering and oil production.
- 25. A power line communications (PLC) system including a power line, an electrical motor having windings, a power supply for powering the motor, a transmitter and a receiver, the transmitter being operable to transmit information to the receiver on a power signal by modulating a leakage current between two windings of a set of windings of the motor.
- 26. A down-well system comprising an electric submersible pump, a power line for connecting the pump to a power supply, and a power line communications (PLC) system that is operable to transmit information on a power signal on the power line by modulating at least one characteristic of the pump.
- 27. A down-well system as claimed in claim 26, wherein the pump includes an electrical motor that has windings, wherein the system is operable to modulate a characteristic between two of the said windings.
- 28. A temperature measurement system for use in a down-well environment comprising a power line for connecting a power supply to an inductive electric load (IEL), a transmitter and a receiver, wherein in use, information indicative of temperature is transmitted from the transmitter to the receiver via the IEL on a power signal by modulating at least one characteristic of the IEL.
- 29. A power line communications (PLC) system including a power line, an electrical motor having windings, a power supply for powering the motor, a transmitter and a receiver, the transmitter being operable to transmit information to the receiver on a power signal by modulating a current flow through a winding of the motor.
Priority Claims (1)
Number |
Date |
Country |
Kind |
9915298.5 |
Jul 1999 |
GB |
|
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent application Ser. No. 10/030,363 filed Jan. 2, 2002, which is the U.S. national phase of PCT Patent Application No. PCT/GB00/02529 filed Jun. 30, 2000, which claims priority of United Kingdom Application No. 9915298.5 filed Jul. 1, 1999.
Continuations (1)
|
Number |
Date |
Country |
Parent |
10030363 |
Jan 2002 |
US |
Child |
10886321 |
Jul 2004 |
US |