Remote control of fluorescent lamp ballast using power flow interruption coding with means to maintain filament voltage substantially constant as the lamp voltage decreases

• US 5,107,184 A
• Filed: 08/13/1990
• Issued: 04/21/1992
• Est. Priority Date: 08/13/1990
• Status: Expired due to Term

• Current Assignee: Electronic Ballast Technology, Inc. (Koninklijke Philips N.V.)
• Original Assignee: Electronic Ballast Technology, Inc. (Koninklijke Philips N.V.)
• Inventors: Yang, Kevin, Hu, Feng-Kang, Shen, Peter S., Jednacz, Thomas C., Lau, Chung M., Zhu, Joshua S.
• Primary Examiner(s): LaRoche, Eugene R.
• Assistant Examiner(s): Neyzari, Ali
• Application Number:
  US07/565,688
• Time in Patent Office: 617 Days
• Field of Search: 315/291, 315/294, 315/307, 315/209 R, 315/205, 315/297, 315/312, 315/361, 315/250, 315/101, 315/106, 315/DIG. 4, 307/40, 340/310 R, 340/310 A, 340/825.03, 340/825.04, 364/492, 364/493
• US Class Current: 315/291
• CPC Class Codes: H02J 13/00009 using pulsed signals
• CPC Class Codes: H02J 13/0001 using modification of a parameter of the network power signal
• CPC Class Codes: H05B 41/36 Controlling
• CPC Class Codes: H05B 41/3927 by pulse width modulation H05B41/3922 takes precedence
• CPC Class Codes: H05B 47/185 via power line carrier transmission
• CPC Class Codes: Y02B 70/30 Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
• CPC Class Codes: Y02B 90/20 Smart grids as enabling technology in buildings sector smart grids supporting the management or operation of end-user stationary applications in general, or like technologies with no associated climate change mitigation effect Y04S20/00
• CPC Class Codes: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y04S 20/246 the system involving the remote operation of lamps or lighting equipment
• CPC Class Codes: Y04S 40/121 using the power network as support for the transmission
• CPC Class Codes: Y10S 315/04 Dimming circuit for fluorescent lamps

Abstract

A dimming ballast system wherein the light output of the lamp is controlled by a remote source. The ballast output voltage is regulated by a voltage control feedback loop, the dimming function being achieved by varying the set point of the control loop. The remote control signal, coded by interrupting the current flow to the ballast for a short period, is processed digitally by a microcomputer which generates information to vary the control set point. Circuit means are provided to control the filament voltage of the fluorescent lamps such that as the lamps are dimmed down, the filament voltage is maintained or slightly increased, thus prolonging lamp life and stabilizing the lamp light output.

Claims

1. A system for controlling a plurality of devices located in a structure having existing power lines such that each device operates at either a first or second condition comprising:

a source of AC power located in said structure;

encoder means remote from said devices responsive to said power source for generating a cyclical signal having a plurality of adjacent pulses in each cycle, at least one pulse in each cycle being missing;

decoder means; and

means for transmitting said pulse signal to said decoder means over said power lines, said decoder means decoding each cyclical pulse signal and generating a DC voltage having a first or second magnitude, a DC voltage of said first magnitude causing each of said devices to operate at said first condition, a DC voltage of said second magnitude causing each of said devices to operate at said second magnitude.

2. The system of claim 1 wherein the magnitude of said DC voltage is set by the time period between missing pulses in succeeding cycles in said cyclical AC signal.

3. The system as defined in claim 2 wherein said encoding means comprises a microcomputer.

4. The system as defined in claim 3 wherein said decoder means comprises a microcomputer.

5. The system of claim 4 wherein said device comprises a fluorescent lamp.