Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
  • H05B41/14—Circuit arrangements
  • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
  • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
  • H05B41/282—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices
  • H05B41/2825—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices by means of a bridge converter in the final stage
  • H05B41/2827—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices by means of a bridge converter in the final stage using specially adapted components in the load circuit, e.g. feed-back transformers, piezoelectric transformers; using specially adapted load circuit configurations
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
  • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
  • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
  • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
  • H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
  • H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
  • H02M7/5383—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a self-oscillating arrangement
  • H02M7/53832—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a self-oscillating arrangement in a push-pull arrangement

Definitions

• Inverter circuit with a control circuit for leading transistors more effectively into a turned-off state.
• the present invention relates to an inverter circuit, ccjnprising:
• a load circuit including a series connection of in ⁇ ductive winding and capacitor and being connected across a point between transistors and a power source
• a base current control circuit including the inductive winding's secondary winding and the base control transformer's winding, connected to said secondary winding.
• the frequency and/or amplitude of a resonance circuit current may fluctuate considerably with varying load.
• An object of the invention is to provide an inverter circuit which includes a base current control circuit for observing both the state of a load and the state of a transistor.
• fig. 1 shows a circuit diagram of an inverter circuit of the invention applied as a ballast for a discharge lamp
• OM .-r IP & KA fig. 2 shows a voltage division diagram of a base current control circuit, the respective volt ⁇ ages being indicated in fig. 1 ' in the situat ⁇ ion where transistor 1 is conductive.
• a load circuit comprising an in ⁇ ductive winding 7 and capacitors 10 and 11 connected in series therewith, the current flowing through said capacitors alternately on successive half-cycles.
• a connection in parallel consisting of a lamp 8 and an ignition capacitor 9.
• Resonance capacitors 10 and 11 are accompanied by stabilizing diodes 23 and 24 which restrict a voltage across capacitors 10 and 11 in a manner that the voltage will be stabilized at point 22.
• ⁇ .NA Protective diodes 14 and 15 provide the current of in ⁇ ductance 7 with a flow path when both transistors 1 and 2 are in non-conductive state.
• the base current control circuit includes a secondary winding 16 for inductive, winding 7, said secondary winding being connected in series with a winding .17 of base control transformer 3.
• the base current control circuit closes itself through a diode 21 and the collector- emitter circuit of transistor 1. Accordingly, when transistor 2 is in conductive state, the control circuit closes itself through a diode 20 and trans ⁇ istor 2. Whilst one of the diodes 20, 21 closes the circuit of said control circuit, the other diode will prevent the current from flowing through the presently conductive transistor and control circuit to the power source terminal which is opposite relative to the presently conductive transistor.
• a control circuit series resistor 18 limits the control current to proper strength.
• a capacitor 19 is not absolutely necessary but it orivides the following action: With transistor 1 or 2 turning non-conductive, a current peak produced by the circuit inductance strives to pass through diode 20 or 21 in wrong direction. In order to eliminate the effect of this current peak on a current trans ⁇ former made up by windings 17 and 5, said peak is passed through capacitor 19.
• OM ⁇ J?NA The operation of a base current control circuit proceeds as follows. It is presumed that transistor 1 is in conductive state. The collector current of transistor 1 begins to fall in this example at a falling rate determined by the resonance frequency of a load circuit. Falling of the current in winding 4 results in the corresponding fall of a base current flowing through winding 5. When the base current falls down to zero and turns negative, the transistor still remains con ⁇ ductive for a short period due to the stored charge carriers. As the base current grows in negative di ⁇ rection until the charge carriers are eliminated, the transistor will be switched off. In order to switch off transistor 1 before transistor 2 turns conductive, the base current control circuit functions as follows.
• a voltage U, inducing in winding 16 is dependant on the falling rate of the collector current of transistor 1, selected to be conductive in this study.
• the falling rate or rate of decrease is sufficient to generate voltage U, which together with voltage U- exceeds the voltage drop ⁇ ⁇ of transistor and the biasing voltage of diode 21, a control current begins to flow in the control circuit.
• the control current generated by hymnage U 3 loads by way of a current transformer made up by windings 17 and 5/6 a control transformer 3 in a manner that the decrease, reversal of the forward base current of transistor 1 and back ⁇ ward increase will be sped up, the elimination of charge carriers or transmitters from the transistor being sped up accordingly, and the transistor can be switched off more quickly.
• Essential in this respect is also that the base current is not acted upon until in the collector current decrease phase, whereby the transistor losses shall not increase due to the fact the transistor would be too early switched out of the saturation where its voltage drop is at minimum.
• the control automatic ⁇ ally observes differences in the characteristics of individual transistors. Since the winding voltage U 3 is in series with the collector-emitter voltage U- of a given conductive transistor 1 or 2, said voltage U.. decreases control voltage U 3 the more the higher said collector-emitter voltage U 1 is. On the other hand, if U-. is low and transistor is deep in saturation and switched off slowly, voltage U_. will decrease control voltage U 3 less, the latter thus generating a higher control current which in turn increases the load on transformer 3 for decreasing and reversing and/or in ⁇ creasing in negative direction at a faster rate.

Landscapes

• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Inverter Devices (AREA)
• Circuit Arrangements For Discharge Lamps (AREA)
• Power Conversion In General (AREA)

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Publications (1)

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ID=8517696

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Cited By (4)

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Citations (2)

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• 1983
  • 1983-09-06 FI FI833186A patent/FI68935C/fi not_active IP Right Cessation
• 1984
  • 1984-09-05 DE DE8484903442T patent/DE3474398D1/de not_active Expired
  • 1984-09-05 EP EP84903442A patent/EP0155303B1/en not_active Expired
  • 1984-09-05 WO PCT/FI1984/000061 patent/WO1985001180A1/en active IP Right Grant
  • 1984-09-05 US US06/732,006 patent/US4603378A/en not_active Expired - Fee Related

Patent Citations (2)

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