US3668434A - Noise suppressing a c phase control system - Google Patents

Noise suppressing a c phase control system Download PDF

Info

Publication number
US3668434A
US3668434A US30135A US3668434DA US3668434A US 3668434 A US3668434 A US 3668434A US 30135 A US30135 A US 30135A US 3668434D A US3668434D A US 3668434DA US 3668434 A US3668434 A US 3668434A
Authority
US
United States
Prior art keywords
transistor
power source
power
capacitor
power transistor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US30135A
Other languages
English (en)
Inventor
Heinrich-Josef Brungsberg
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BBC Brown Boveri AG Germany
Original Assignee
Bbc Brown Boveri & Cie
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bbc Brown Boveri & Cie filed Critical Bbc Brown Boveri & Cie
Application granted granted Critical
Publication of US3668434A publication Critical patent/US3668434A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B15/00—Suppression or limitation of noise or interference
    • H04B15/02—Reducing interference from electric apparatus by means located at or near the interfering apparatus
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S315/00—Electric lamp and discharge devices: systems
    • Y10S315/04—Dimming circuit for fluorescent lamps

Definitions

  • An a-c phase control circuit includes a power transistor for phase control replacing the thyristor generally used for thispurpose.
  • a-c phase control is applied in reference to a process of rapid On-OFF switching which connects an a-c supply to a load for a controlled fraction of each cycle.
  • A-C phase control is applied extensively as a means for controlling the average power to various loads such as, for instance, electric lamps, electric heaters and electric motors.
  • Electric circuitry for controlling the average power to an electric lamp by means of a-c phase control is referred to as a phase control dimmer. This invention lends itself well to a-c phase control dimmers.
  • thyristor circuitry including one or more power thyristors.
  • rate of rise of the current following triggering of the power thyristor is very high.
  • the frequency spectrum of the steeply rising currents encompasses frequencies ranging from about 150 k Hertz to 30 m Hertz. These frequencies constitute radio noise.
  • Generally chokes and capacitors may be used as effective radio noise suppressors.
  • Such noise suppressors are effective where relatively high noise frequencies occur, but are relatively ineffective at frequencies less than 1 m Hertz, i.e., in the range of medium and long wave radiation.
  • Even complex filter circuits which are applied to suppress radio noise resulting from mechanical switching devices are relatively ineffective to suppress radio noise resulting from ac phase control by means of thyristors, and the bulk and cost of such filter circuits tend to be excessive.
  • the prime object of the present invention is to provide means applicable in conjunction with a-c phase control for avoiding radio noise, and more particularly to control the rate of rise of the a-c phase controlled load current in such a way as to keep the high frequency components thereof at a permissible level, and to achieve these ends with a minimum of bulk, a minimum of cost and a minimum of parts.
  • An a-c phase control circuitry embodying this invention includes an a-c power source, a load supplied from said power source, a power transistor controlling the flow of current from said power source to said load, means for effecting rapid ON- OFF switching of said power transistor to conductively connect said power source for a controlled fraction of each cycle of said power source to said load, and manually operable means for varying said controlled fraction of each cycle of said power source during which said power source is conductively connected to said load by the intermediary of said power transistor.
  • FIG. I is a diagrammatic representation of a dimmer circuit embodying the present invention.
  • FIG. 2a shows diagrammatically a current trace of a current occurring in a prior art a-c phase control circuit wherein a-c phase control is effected by a thyristor;
  • FIG. 2b shows diagrammatically a current trace of a current occurring in the circuit of FIG. 1 wherein a-c phase control is efiected by a transistor;
  • FIG. 3 is a complete circuit diagram of an a-c phase control circuit embodying the present invention.
  • FIG. 4 is a complete circuit diagram of a modification of the circuit of FIG. 3 particularly intended to form a monolithic integrated circuit of the LS! type;
  • FIGS. 5a-5c are voltage and current traces referring to the circuitry of FIG. 3.
  • reference characters a and b have been applied to indicate a pair of conductors or leads. An a-c voltage prevails between conductors or leads a and b.
  • Reference numeral 5 has been applied to indicate a load, and more particularly an incandescent electric lamp.
  • the circuit of load 5 includes disconnect switch 1 and full wave rectifier bridge 2. The latter is provided with four power diodes 2a,2b,2c,2d.
  • Power transistor 3 conductively interconnects two of the terminals of full wave rectifier bridge 2, i.e., its d-c terminals.
  • Reference character 6 has been applied to generally indicate a control circuit for transistor 3.
  • Control circuit 6 can be adjusted by adjusting means such as knob or handle 7. By adjusting knob or handle 7 the fraction of half cycles during which power transistor 3 carries current from lead a to b may be varied.
  • Control circuit 6 is connected by leads C,,C,,C and C to bridge circuit 2, the ends of leads C C, and C. remote from control circuit 6 being conductively connected to terminals of bridge circuit 2 and the end of lead C remote from control circuit 6 being conductively connected to the base of power transistor 3.
  • Conu'ol circuit 6 may take various forms as long as it performs the function of a-c phase control of power transistor 6, i.e., controls the phase angle at which power transistor 6 is turned on periodically.
  • FIGS. 20 and 2b show current plotted against time, orelectrical angles, respectively, for a total of 2 1r. In both instances current flow is initiated at the same electrical angle a.
  • FIG. 2a referring to a thyristor a-c phase control circuit shows a very steep rise of the current I following triggering of the thyristor at the electrical angle a. The rate of rise of the current is )8, and B is virtually According to FIG. 2b referring to the circuit of FIG. 1 wherein phase-control is efiected by turning transistor lion and off, the rate of rise B, of the current is much less than in FIG. 2a, i.e. B, B or [3, 90.
  • the current trace of FIG. 2a involves a wide band of frequencies, up to the highest frequencies.
  • the current trace of FIG. 2b involves a much narrower band of frequencies, and these may be kept below a specified permissible band width N.
  • a-c lead a is conductively connected to a-c lead b by the intermediary of a full wave rectifier bridge including diodes 2a',2b',2c'2d' and power transistor 3'.
  • Power transistor 3 includes emitter 3a, base 3b and collector 3c. beads C, and C are connected to the two do terminals of the above referred-to bridge circuits and the emitter 3a and the collector 3c of transistor 3' are conductively connected to the same terminals, a resistor 17' being included in the collector circuit of power transistor 3.
  • a resistor 8' is arranged in lead C and leads C, and C, are conductively interconnected by Zener diode 9' limiting the (1-0 voltage prevailing across leads C,',C substantially at a predetermined level.
  • Capacitor 10 and regulating resistor 1 l are connected in series and shunted across Zener diode 9'.
  • Reference character 12 has been applied to generally indicate a unijunction transistor or silicon double base diode. The emitter of the latter is conductively connected to a point between capacitor 10 and regulating resistor 11'.
  • One base of unijunction transistor 12' is conductively connected by lead C to one terminal of regulating resistor 11, and the other base of unijunction transistor 12 is conductively connected by lead C, to the gate of auxiliary thyristor 13.
  • the latter interconnects the d-c terminals of bridge circuit 2a',2b',2c',2d',3', and resistor 14 is included in the anode circuit of auxiliary thyristor 13'.
  • Resistor 16 connects the anode of auxiliary thyristor l3 and the base of power transistor 3'.
  • Reference character 15' has been applied to indicate a capacitor of which one terminal is conductively connected to the base 3b of power transistor 3 and the other terminal is conductively connected to the emitter 3a of power transistor 3'.
  • the circuitry of FIG. 3 operates as follows:
  • auxiliary thyristor 13' is triggered. Triggering of auxiliary thyristor 13' establishes a direct current path from the positive to the negative terminal of full wave bridge 2a,2b',2c',2d',3' through auxiliary thyristor l3 and resistor 14 which are connected in series.
  • Resistor 14 is dimensioned in such a way that the holding current of auxiliary thyristor I3 is reached shortly after the time of voltage zero. Resistor 17 is required for the proper control of the base current of power transistor 3'.
  • FIG. 4 the parts corresponding to parts in FIG. 3 have been indicated by the same reference characters to which two primes rather than one single prime as in FIG. 3 have been added.
  • FIG. 4 is substantially self-explanatory, and requires additional description only to the extent that the circuitry shown therein differs from that shown in FIG. 3.
  • FIG. 4 differs from FIG. 3 only inasmuch as the power transistor 3' of the latter has been substituted in the former by a cascade of two transistors, i.e., auxiliary transistor 18 and power transistor 3".
  • Auxiliary transistor 18" operates as an amplifier. Assuming that there is the same time constant in the circuitry of FIG. 3 and that of FIG. 4, the provision of auxiliary transistor 18" makes it possible to greatly increase the magnitude of resistor 16" relative to that of resistor 16' and to greatly reduce the magnitude of capacitor 16' relative to that of capacitor 16'.
  • FIGS. 511,51: and 5c the first mentioned figure shows the voltage U(3a,3c) across theemitter 3a and the collector 3c of power transistor 3 plotted against time. This voltage rises sinusoidally and collapses relatively rapidly when power transistor 3' is turned on.
  • FIG. 5b shows the voltage U(15) prevailing across capacitor 15 plotted against time t andFIG. 5c shows the load current I, flowing through power transistor 3' and through load 5' plotted against time.
  • unijunction transistor 12' and capacitor 10 operate as a free running oscillation generator under the control of variable resistor 11'.
  • This free running oscillation generator is energized by the voltage prevailing across the d-c terminals of fullwave rectifier bridge 2a',2b,2c',2d',3' and triggers auxiliary thyristor 13. The latter, in turn, controls the flow of current I through power thyristor 3' and load 5 I claim as my invention.
  • An a-c phase control circuitry with reduced radio noise including in combination a. an a-c power source;
  • a full wave diode rectified bridge having a-c terminals conductively connected to said power source and d-c terminals conductively connected to a power transistor;
  • a free running oscillation generator energized by the d-c voltage prevailing between said d-c terminals of said rectifier bridge and controlling rapid ON-OFF switching of said power transistor;
  • said capacitor and other constituent circuit elements of said circuitry being formed by a monolithic integrated circuit
  • manually operable means for varying the fraction of each cycle of said power source during which said power source is conductively connected to said load.
  • An a-c phase control circuitry with reduced radio noise including in combination a. an a-c power source;
  • a full wave diode rectifier bridge having a-c terminals conductively connected to said power source and d-c terminals conductively connected to a power transistor;
  • a free running oscillation generator energized by the d-c voltage prevailing between said d-c terminals of said rectifier bridge and controlling rapid ON-OF F switching of said power transistor, said free running oscillation generator being formed by a capacitor and a unijunction transistor, said unijunction transistor controlling the gate circuit of an auxiliary thyristor to trigger said auxiliary thyristor;
  • An a-c phase control circuitry as specified in claim 2 including lead means conductively connecting said d-c terminals of said rectifier bridge, a serially connected resistor and Zener diode providing reduced and stabilized operating voltage for said free running oscillation generator being included in said lead means.
  • An a-c phase control light dimmer circuitry with reduced radio noise including in combination a. an a-c power source;
  • a power transistor controlling the flow of current from said power source to said electric lamp
  • means for effecting rapid ON-OFF switching of said power transistor including an auxiliary transistor and a capacitor, said auxiliary transistor and said power transistor being cascade connected and said auxiliary transistor and said power transistor being shunted by a capacitor, and said capacitor and other constituent elements of said dimmer circuitry being formed by a monolithic integrated circuit;
  • manually operable means for varying a controlled fraction of each cycle of said power source during which said power source is conductively connected to said electric lamp.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Circuit Arrangement For Electric Light Sources In General (AREA)
  • Discharge-Lamp Control Circuits And Pulse- Feed Circuits (AREA)
  • Rectifiers (AREA)
  • Circuit Arrangements For Discharge Lamps (AREA)
US30135A 1969-04-25 1970-04-20 Noise suppressing a c phase control system Expired - Lifetime US3668434A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19691921122 DE1921122B2 (de) 1969-04-25 1969-04-25 Einrichtung zur steuerung eines aus einem wechselstromnetz gespeisten verbrauchers mittels eines leistungstransistors

Publications (1)

Publication Number Publication Date
US3668434A true US3668434A (en) 1972-06-06

Family

ID=5732333

Family Applications (1)

Application Number Title Priority Date Filing Date
US30135A Expired - Lifetime US3668434A (en) 1969-04-25 1970-04-20 Noise suppressing a c phase control system

Country Status (4)

Country Link
US (1) US3668434A (enrdf_load_stackoverflow)
DE (1) DE1921122B2 (enrdf_load_stackoverflow)
FR (1) FR2044741A1 (enrdf_load_stackoverflow)
GB (1) GB1289641A (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4359681A (en) * 1980-05-01 1982-11-16 Westinghouse Electric Corp. Alternating current power controller with DC transistor switching and an internal DC power supply
DE3531021A1 (de) * 1984-09-18 1986-03-27 Smiths Industries P.L.C., London Elektrischer schalter
US4728866A (en) * 1986-09-08 1988-03-01 Lutron Electronics Co., Inc. Power control system
US5247242A (en) * 1990-01-12 1993-09-21 Toshiba Kikai Kabushiki Kaisha Output module
US20070127179A1 (en) * 2005-12-05 2007-06-07 Ludjin William R Burnout protection switch

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2935674A (en) * 1958-03-17 1960-05-03 Globe Ind Inc Motor control
US3025418A (en) * 1959-12-24 1962-03-13 United Aircraft Corp Quadrature stripping circuit
US3091704A (en) * 1960-01-21 1963-05-28 W F And John Barnes Company Bridge circuit control means with ganged switches effecting leakage compensation
US3146392A (en) * 1961-08-02 1964-08-25 Gen Electric Control circuits employing unijunction transistors for firing controlled rectifiers
US3239685A (en) * 1962-09-18 1966-03-08 Bendix Corp Control circuit

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2935674A (en) * 1958-03-17 1960-05-03 Globe Ind Inc Motor control
US3025418A (en) * 1959-12-24 1962-03-13 United Aircraft Corp Quadrature stripping circuit
US3091704A (en) * 1960-01-21 1963-05-28 W F And John Barnes Company Bridge circuit control means with ganged switches effecting leakage compensation
US3146392A (en) * 1961-08-02 1964-08-25 Gen Electric Control circuits employing unijunction transistors for firing controlled rectifiers
US3239685A (en) * 1962-09-18 1966-03-08 Bendix Corp Control circuit

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4359681A (en) * 1980-05-01 1982-11-16 Westinghouse Electric Corp. Alternating current power controller with DC transistor switching and an internal DC power supply
DE3531021A1 (de) * 1984-09-18 1986-03-27 Smiths Industries P.L.C., London Elektrischer schalter
US4705963A (en) * 1984-09-18 1987-11-10 Smiths Industries Public Limited Company AC controlled diode switch
US4728866A (en) * 1986-09-08 1988-03-01 Lutron Electronics Co., Inc. Power control system
US5247242A (en) * 1990-01-12 1993-09-21 Toshiba Kikai Kabushiki Kaisha Output module
US20070127179A1 (en) * 2005-12-05 2007-06-07 Ludjin William R Burnout protection switch

Also Published As

Publication number Publication date
GB1289641A (enrdf_load_stackoverflow) 1972-09-20
FR2044741A1 (enrdf_load_stackoverflow) 1971-02-26
DE1921122B2 (de) 1972-12-07
DE1921122A1 (de) 1971-01-07

Similar Documents

Publication Publication Date Title
US3243689A (en) Power control circuit
US3681654A (en) Light-regulating power supply circuit for gaseous discharge lamp
US3250978A (en) Controlled switching circuit for d. c. supply for inductive or regenerative loads
US3731182A (en) Phase control type dimming system with means to compensate for the hysteresis effect
US2981880A (en) Speed-regulating control system for series commutator motor
US4031458A (en) A.C. voltage regulator employing thyristor
US3766409A (en) Ac power control apparatus with improved switch driver means
US3668434A (en) Noise suppressing a c phase control system
US3484623A (en) Power control circuit using bistable switching device
US3401327A (en) Inverter circuit having increased frequency starting
US4013921A (en) Warning light control
US3273043A (en) Regulated rectifier
US3601688A (en) Voltage regulator for permanent magnet generators
US3277362A (en) Phase control device
US3265956A (en) Electrical apparatus
US3358186A (en) Dimmer for electric lamps
US3320521A (en) Direct current signal control device
US3638043A (en) Current control device
US3694727A (en) Inverter device
US3260924A (en) Direct current voltage converter
US3700962A (en) Control circuit for mercury arc lamps
US3231812A (en) Electric circuits for controlling the supply of electric current to a load
US3852657A (en) Commutation control for inverter circuit
US3872371A (en) Power control system
US3361932A (en) A.c. operated spark ignition apparatus with compensation for changes in the frequency of the a.c. source