Phase detecting device for determining phase angle between two electrical signals

• US 5,521,491 A
• Filed: 05/16/1995
• Issued: 05/28/1996
• Est. Priority Date: 08/23/1993
• Status: Expired due to Term

• Current Assignee: Echelon Corporation (Renesas Electronics Corporation)
• Original Assignee: Echelon Corporation (Renesas Electronics Corporation)
• Inventors: Najam, Zahid
• Primary Examiner(s): Wieder, Kenneth A.
• Assistant Examiner(s): Solis, Jose M.
• Application Number:
  US08/441,957
• Time in Patent Office: 378 Days
• Field of Search: 324/107, 324/108, 324/66, 324/521, 324/527, 324/528, 324/86, 340/658, 340/310.01, 340/538
• US Class Current: 324/86
• CPC Class Codes: G01R 29/18 Indicating phase sequence; Indicating synchronism
• CPC Class Codes: G01R 31/40 Testing power supplies testing photovoltaic devices H02S50/10

Abstract

A transmitting box is connected to a first electrical outlet in a building. The phase of the first electrical outlet is used as the reference phase. The transmitter box senses each of the zero-cross-overs of the reference phase and injects a data packet of the data carrier frequency at each zero-cross-over. A receiving box is connected to a second electrical outlet in the building. The second electrical outlet has an unknown phase which may be different from the reference phase. The receiver box receives each data packet and senses each phase zero-cross-over of the unknown phase. The receiver box uses the time between each reception of a data packet and each detection of an unknown phase zero-cross-over to determine the phase angle of the unknown phase relative to the reference phase.

Claims

1. An apparatus for use in a polyphase electrical power distribution system for determining the phase angle and wiring phase of an unknown phase voltage relative to a reference phase voltage, comprising:

a first circuit for generating a data packet at a point in time when a predetermined point of the reference phase voltage is detected, the data packet having a duration that is substantially shorter than the period of the reference phase voltage; and

a second circuit for receiving the data packet and for detecting a point in time when a predetermined point of the unknown phase voltage occurs, the second circuit including means for determining the phase angle of the unknown phase voltage relative to the reference phase voltage based on an amount of time measured between reception of the data packet and detection of the point in time when the predetermined point of the unknown phase voltage occurs.

2. The apparatus for use in a polyphase electrical distribution system according to claim 1, the predetermined points of the reference and unknown phase voltages being defined by voltage values and slopes of the respective phases at those respective voltage values.

3. The apparatus for use in a polyphase electrical distribution system according to claim 2,

wherein the predetermined point of the reference phase voltage is defined as a point on the reference phase voltage with a zero voltage and a positive slope, and

wherein the predetermined point of the unknown phase voltage is defined as a point on the unknown phase voltage with a zero voltage and a positive slope.

4. The apparatus for use in a polyphase electrical distribution system according to claim 1, the first circuit being for generating a data packet and for injecting the data packet onto the reference phase voltage at the point in time when the predetermined reference point of the reference phase voltage is detected.

5. The apparatus for use in a polyphase electrical distribution system according to claim 1, the first circuit being for generating a data packet and for transmitting the data packet at the point in time when the predetermined reference point of the reference phase voltage is detected.

6. The apparatus for use in a polyphase electrical distribution system according to claim 5, wherein the data packet is transmitted on radio frequency.

7. An apparatus for use in a polyphase electrical power distribution system for determining the phase angle and wiring phase of an unknown phase voltage relative to a reference phase voltage, the unknown phase voltage and the reference phase voltage being parasitically coupled, the apparatus comprising:

a first circuit for placing a time-stamp signal onto the reference phase voltage when a reference point on the reference phase voltage is detected, the time-stamp signal having a duration that is substantially shorter than the period of the reference phase voltage;

and

a second circuit for receiving the time-stamp signal via the parasitic coupling and for detecting a reference point on the unknown phase voltage, the second circuit including means for determining the phase angle of the unknown phase voltage relative to the reference phase based on an amount of time measured between reception of the time-stamp signal and detection of the reference point on the unknown phase voltage.

8. The apparatus for use in a polyphase electrical distribution system according to claim 7, wherein the relative position of the reference point on the reference phase voltage is the same as the relative position of the reference point on the unknown phase voltage.

9. An apparatus for use in a polyphase electrical power distribution system for determining the phase angle and wiring phase of an unknown phase voltage relative to a reference phase voltage, comprising:

first detection means for detecting each point in time when a voltage of the reference phase voltage reaches approximately zero with positive slope;

first injection means for injecting a data packet onto the reference phase voltage at each of the detected points in time when a voltage of the reference phase voltage reaches approximately zero with positive slope, the data packet having a duration that is substantially shorter than the period of the reference phase voltage;

reception means for receiving each data packet;

second detection means for detecting each point in time when a voltage of the unknown phase voltage reaches approximately zero with positive slope; and

determining means for determining the phase angle of the unknown phase voltage relative to the reference phase voltage, based on an amount of time measured between reception of a data packet and detection of a point in time when a voltage of the unknown phase voltage reaches approximately zero with positive slope.

10. A method for use in connection with a polyphase electrical power distribution system, the method for determining the phase angle and wiring phase of a unknown phase voltage in a second electrical outlet relative to a reference phase voltage in a first electrical outlet, comprising the following steps:

connecting a first circuit to the first electrical outlet, the first electrical outlet having a reference signal with a reference phase voltage;

connecting a second circuit to the second electrical outlet, the second electrical outlet having a unknown signal with a unknown phase voltage;

detecting each point in time when a voltage of the reference signal in the first electrical outlet reaches approximately zero with positive slope;

sending a data packet having a duration that is substantially shorter than the period of the reference phase voltage from the first circuit to the second circuit at each of the detected points in time when a voltage of the reference signal reaches approximately zero with positive slope;

receiving each data packet by the second circuit;

detecting each point in time when a voltage of the unknown signal reaches approximately zero with positive slope; and

determining the phase angle of the unknown phase voltage relative to the reference phase voltage based on an amount of time measured between reception of a data packet and detection of a point in time when a voltage of the unknown signal reaches approximately zero with positive slope.

11. A method for use in a polyphase electrical power distribution system for determining the phase angle and wiring phase of an unknown phase voltage relative to a reference phase voltage, comprising the following steps:

sending a signal when a predetermined point of the reference phase voltage is detected, the signal having a duration that is substantially shorter than the period of the reference phase voltage;

receiving the signal;

detecting when a predetermined point of the unknown phase voltage occurs; and

determining the phase angle of the unknown phase voltage relative to the reference phase voltage based on an amount of time measured between reception of the signal and detection of when the predetermined point of the unknown phase voltage occurred.

12. A method for determining the phase angle and wiring phase of a unknown phase voltage relative to a reference phase voltage, the two phases being parasitically coupled, the method comprising the following steps:

connecting a transmitter circuit to a reference electrical outlet having a reference signal with a reference phase voltage;

connecting a receiver circuit to a unknown electrical outlet having a unknown signal with a unknown phase voltage;

sensing a first predetermined point located on the reference signal;

inserting a data packet into the reference signal, the data packet having a duration that is substantially shorter than the period of the reference phase voltage;

receiving the data packet via the parasitic coupling with the receiver circuit;

starting a timer at a start time, upon reception of the data packet;

sensing a second predetermined point located on the unknown signal;

stopping the timer at a stop time, upon sensing the second predetermined point located on the unknown signal;

computing a difference between the start time and the stop time; and

determining the phase angle of the unknown phase voltage relative to the reference phase voltage based upon the computed difference.

13. The method for determining the phase angle of an unknown phase voltage relative to a reference signal according to claim 12, wherein the relative position of the first predetermined point located on the reference phase voltage is the same as the relative position of the second predetermined point located on the unknown signal.