Stabilized voltage converter for fluorescent lamps

 

(57) Abstract:

The alleged invention relates to electrical engineering and can be used in lighting installations for various purposes when powered by unstable voltage source. The technical result of the invention is to improve the stability of the glow of a fluorescent lamp. The stability of the glow of a fluorescent lamp is achieved by introducing an additional primary winding of the power transformer included in the diagonal of a full-wave rectifier. In another diagonal of the rectifier are connected in parallel to the capacitor and the second and third resistors. At the same time, the secondary winding of the transformer in parallel fluorescent lamp connected resonant circuit. When increasing the input voltage increases, the voltage on the primary winding and the control input of the transistor, which increases the operating frequency of the Converter, which in turn causes a reduction gear ratio of the resonant circuit. 1 Il.

The alleged invention relates to electrical engineering and can be used in lighting installations for various purposes when powered unstable and the second conclusion of the primary winding of which is connected to the collector of the first transistor, device is activated by the input of the first diode, the second output of the primary winding of the power transformer is connected to the collector of the second transistor device is activated by the input of the second diode, the emitters of the first and second transistors integrated and connected to the first output for connection to a power source, to the United emitters of the third and fourth transistors, the collectors of which are connected respectively to the bases of the first and second transistors and to a circuit consisting of series-connected first resistor and additional primary winding of the power transformer, the midpoint of the primary winding of which is connected to the base of the fifth transistor and through a second resistor to the second output connection of the power source, to the emitter of the fifth transistor, the collector of which respectively through the third and fourth resistors connected to the bases of the third and fourth transistors, the secondary winding of the power transformer through an inductive ballast connected to the luminescent lamp /A. S. USSR N 1654990, H 05 B 41/26, 30.12.88,/.

The disadvantage of this device is the instability of the fluorescent lamp when the variance of the input voltage. In addition, should be carefully selected .

Known voltage Converter with current control containing the power transformer, the first output of the primary winding through which the first collector winding of the current transformer is connected to the collector of the first transistor device is activated the first diode, the base of the first transistor is connected to the first output of the first base winding of the current transformer, the second output of which is connected through a first resistor to the first output for connecting a power source to the second output for connection to a power source through a second diode and through the first capacitor to the first output of the second base winding of the current transformer, the second output of which is connected to the base of the second transistor device is activated by a third diode, the emitters of the first and second transistors integrated and connected to the second output connection of the power source, the collector of the second transistor through the second collector winding of the current transformer is connected to the second output of the primary winding of the power transformer, the midpoint of which is connected to the first output for connecting a power source to the secondary winding of the power transformer connected load /see "Electronic technology is atobatele is the instability of the output voltage, what complicates its use in power circuits of fluorescent lamps.

The result of the proposed invention is to increase the stability of the glow of a fluorescent lamp.

The result is achieved that the voltage Converter containing a power transformer, the first output of the primary winding through which the first collector winding of the current transformer is connected to the collector of the first transistor device is activated the first diode, the base of the first transistor is connected to the first output of the first base winding of the current transformer, the second output of which is connected through a first resistor to the first output for connecting a power source to the cathode of the second diode through the first capacitor to the second output for connecting a power source to the first output of the second base winding of the current transformer, the second output of which is connected to the base of the second transistor, device is activated by the third diode, the emitters of the first and second transistors integrated and connected to the second output connection of the power source, the collector of the second transistor through the second collector winding of the current transformer is connected to the second output primary obmocne, as well as the secondary winding of the power transformer, the additional primary winding of the power transformer. LC-circuit, connected in parallel to the secondary winding of the power transformer, the second and third resistors, a second capacitor, a full-wave rectifier, a first diagonal of which is connected the primary winding of the power transformer, the second diagonal are connected in parallel to the second capacitor and the circuit consisting of series-connected second and third resistors, and the first output of the second resistor is connected to the second output connection of the power source, the second terminal of the second resistor is connected to the anode of the second diode.

Stabilized voltage Converter for fluorescent lamps is presented in the figure.

The Converter includes a first output 1 to connect the power source connected to the first output of the first resistor 2, the second terminal of which is connected to the first output of the first capacitor 3, the second terminal of which is connected to the second pin 4 to connect the power source device is activated directly included the first diode 5, the first transistor 6, the second resistor 7, the first output to the resistor 2, to the combined findings of the first 10 and second 12 base windings of the current transformer 9, the other terminals of which are connected respectively to the bases of the first 6 and second 14, transistors, emitters of which are combined and connected to the second pin 4, the collector of the first 6 of the transistor is connected through a first collector winding 11 current transformer 9 to the first output of the primary winding 17 of the power transformer 16, the second terminal through which the second collector winding 13 of the current transformer 9 is connected to the collector of the second transistor 14, the device is activated directly included third diode 15, the midpoint 20 of the primary winding 17'-17" power transformer 16 is connected to the first output 1, the first output of the third resistor 21 is connected to the second output of the second resistor 7, the second terminal of the resistor 21 and the second pin 4 to connect the power source are connected respectively to the diagonal of a full-wave rectifier 23, which is connected in parallel with the second capacitor 22, the other diagonal of the rectifier 23 is connected the primary winding 18 of the power transformer 16, the secondary winding 19, which is loaded on L24-C25-path.

The Converter operates as follows.


U10= Ub-e+ U7+ U8< / BR>
where U10- the voltage drop across the winding 10 of the current transformer 9,

Ub-ethe voltage at the transition base-emitter voltage of the transistor 6,

U7- the voltage across the resistor 7,

U6- the voltage across the second diode 8.

In the induction magnetic field, the current transformer core 9 begins to change (fromr- in the first cycle of magnetization to Busin steady state). When you reach a magnitude of the magnetic field core 9 Bslave= Buscurrent coupling of the windings 10 and 11 of the transformer is broken, i.e., the magnetizing current of the transformer 9 reaches a value at which the collector current of the winding 11 is not transformed in the base winding 10. The capacitor 3 starts to run out, latching forced transistor 6. This will cause the change of polarity of the voltage on the windings of the current transformer 9, which will lead to the opening of the transistor 14, and the process repeats. As a result, the secondary winding 19 of the transformer 16 appears rectangular bipolar voltage. The frequency of this voltage defined the word turns the base winding 10 current transformer 9,

Sarticle- the cross-sectional area of the core current transformer 9,

Busthe value of saturation magnetic flux density of the core material of the transformer 9.

As the load on the secondary winding 19 of the transformer 16 is used resonant L24-C25-circuit with a parallel connection of a fluorescent lamp. The natural frequency of the resonant circuit is chosen below the operating frequency of the Converter. In this case, the load for the Converter (resonant circuit) is inductive, i.e., the current through the transistors 6, 14 lags the phase of the voltage on Polubotko 17' and 17" of the transformer 16. To the voltage at the terminals of a fluorescent lamp was constant (largest) and did not depend on changes of the input voltage, the transformer 16 posted winding 18. The turn ratio between windings 17' and 19, 17 and 19, and the parameters L24 and C25 of the resonant circuit are selected so that at a minimum input voltage of the voltage at the terminals of the lamp would correspond to its nominal mode. When increasing the input voltage increases, the voltage on all windings of the transformer 16. The voltage across winding 18 after the rectifying bridge 23 is supplied to the capacitor 22 of the transformer 9, also increases, which increases the operating frequency of the Converter.

Since the operating point is selected to the right of the point of resonance, increasing the operating frequency leads to a decrease of the transmission factor of the resonant circuit L24-C25. Thus the increase in the input voltage is compensated by the decrease of the transmission factor of the resonant circuit. The choice of parameters of the elements of the resonant circuit L24-C25 and resistor 7 can receive the necessary proportionality between the input voltage and operating frequency of the transducer, resulting in the voltage at the terminals of the lamp practically does not depend on the change of input voltage within the specified limits.

Stabilized voltage Converter for fluorescent lamp containing a power transformer, the first output of the primary winding through which the first collector winding of the current transformer is connected to the collector of the first transistor device is activated the first diode, the base of the first transistor is connected to the first output of the first base winding of the current transformer, the second output of which is connected through a first resistor to the first output for connecting a power source to the AC output of the second base winding of the current transformer, the second output of which is connected to the base of the second transistor device is activated by the third diode, the emitters of the first and second transistors integrated and connected to the second output connection of the power source, the collector of the second transistor through the second collector winding of the current transformer is connected to the second output of the primary winding of the power transformer, the midpoint of which is connected to the first output connection of the power source and the secondary winding of the power transistor, characterized in that the additional primary winding of the power transformer, the second and third resistors, a second capacitor, a full-wave rectifier, a first diagonal of which is connected the primary winding of the power transformer, the second diagonal are connected in parallel to the second capacitor and the circuit consisting of series-connected second and third resistors, and the first output of the second resistor is connected to the second output connection of the power source, the second terminal of the second resistor is connected to the anode of the second diode, and connected in parallel to the secondary winding of the power transformer LC-circuit, the natural frequency of the cat is

 

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