UA65418A - Electronic analog of a ballast resistor - Google Patents

Abstract

The proposed electronic analog of a ballast resistor for a luminescence lamp contains a transistor, a resistor, an inductance coil, a power-supply source, an LC series resonance circuit, a capacitive voltage divider, and a stabilitron.

Description

The invention belongs to the field of control technology for fluorescent (gas discharge) lamps, namely to circuits for powering lamps with high-frequency voltage obtained by converting direct current voltage (this direct current voltage can be obtained from alternating current of industrial frequency by a circuit included in the power supply device) . Such devices are called electronic ballasts. At the same time, a high efficiency of conversion of the energy of the power source into energy dissipated by the lamp and an increase in the light output of the lamp (higher efficiency of conversion of electromagnetic energy into a light flux), the possibility of operation from low voltages (from batteries or on-board network), instantaneous or such that programmable (soft), lighting the lamp and increasing its service life.

Electronic ballasts usually contain a specialized microcircuit of the controller, which provides a change in the frequency of alternating current according to a given law, a powerful two-stroke output stage and reactive elements (1). Such electronic ballasts are common devices, their flaws are either a decrease in efficiency with increasing frequency, or a complicated device circuit. In addition, such ballasts are mainly used with supply voltages of hundreds of volts, so they solve the problem of lighting a fluorescent lamp more easily.

Known electronic ballasts containing a direct current to alternating current converter based on a class O amplifier (1). The disadvantages of this scheme include the comparative complexity of the scheme and efficiency, which decreases with increasing frequency.

An electronic ballast based on a class E amplifier allows you to turn on fluorescent lamps when powered by a voltage of 128, ensuring a high efficiency of the device (21I, while ensuring an instant start of the lamp, but the filament is not preheated. The disadvantage of this device is its relative complexity and suitability for small-sized fluorescent lamps .

A possible electronic ballast, created on the basis of an autogenerator, demonstrating the mode of operation of class E

IZI, its disadvantages include operation at high power supply voltage.

Class E |4th amplifier is now a generally recognized and widespread device containing elements that are determined almost unambiguously by the well-known formulas I3-7). These elements include: a capacitor connecting the drain and drain (collector and emitter) of the transistor and a series oscillating circuit containing a load resistance connecting the drain and drain of the transistor. Its functioning, i.e. the form of currents and voltages on the elements of the amplifier, are also strictly defined, therefore the concept of class E is used in defining the features of the invention.

The closest device is the device described in |5.6Y, which contains a single transistor working as an autogenerator! class E. The disadvantage of this device is its unsuitability directly for work as an electronic ballast, because it is not clear the possibility of solving the issues of heating the filament, igniting the lamp and obtaining high efficiency when working on a load, the parameters of which depend on both the operating mode and time Device according to |b6| calculated for one load and one frequency. In the electronic ballast (11, three frequencies are used to assign three modes of operation, obviously, as in the autogenerator! in general, a similar phenomenon may be present. On the other hand, to ensure stable and highly efficient operation of the electronic ballast according to the autogenerator scheme, other rules of reconstruction may be required frequency

An important factor for the operation of fluorescent lamps (increasing their durability) is the correct use of cathode glow. When working with an unheated cathode, the durability of the lamp decreases (11.

The basis of the invention is the task of improving the electronic ballast by implementing it according to the highly efficient scheme of the class E autogenerator with a change in the switching scheme of the fluorescent lamp, which allows to reduce the voltage of the lamp ignition, to ensure the power supply of the electronic ballast from low voltage.

The task is solved due to the fact that the electronic ballast is performed according to the scheme of the autogenerator class E Ib| with the inclusion of a fluorescent lamp through a resistance transformer, (capacitive resistance inverter) with provision of preliminary heating of the filament. In order to store the high efficiency of the class E autogenerator and to ensure generation at low supply voltage, capacitors 5, 7 and 8 are introduced on a powerful transistor, which ensure generation (that is, the fulfillment of the phase balance condition) in the mode of heating the filament, lighting the lamp, and in the constant glow mode (Fig. .1).

The device consists of a powerful field-effect transistor 1, the drain of which is connected to the common wire 16, a choke 2 is connected to the drain of the transistor, the other terminal is connected to the power supply 15, a capacitor 3, which is connected to the common wire 16 by the other terminal, and an inductor 4, to the other capacitor 5 is connected to the output of the coil 4, to which the lamp 6 is connected by one output of the filament, the other output of this filament is connected to the capacitor 7, which is connected to the output of the second filament of the lamp, the other output of the second filament is connected to the common wire 16, the capacitor 8, the other terminal is connected to the common wire and the capacitor 9, the other terminal is connected to the capacitor 10 and the inductor 11, the capacitor 10, the other terminal is connected to the common wire, and the inductor 11, the other terminal is connected to the gate of the transistor 1, a resistor is also connected to the gate of the transistor 12, the other terminal is connected to the power source 15, resistor 13, the other terminal at connected to the common wire and two zener diodes 14 connected to each other, connected by a free terminal to the common wire 16.

The device works in the following way: when a constant supply voltage is applied to the circuit, a divider made of resistors 12, 13 ensures that a bias voltage is applied to the gate (input) of transistor 1, which turns it into active mode, the current flowing through the transistor excites oscillations in the circuit, formed by inductance 4, capacitors 5, 7 and 8 and the resistances of the lamp filaments. These oscillations along the feedback circuit formed by the divider on capacitors 9 and 10 and the inductance 11 are transmitted to the input of the transistor, which closes the positive feedback circuit and creates oscillations in the generator at a frequency that due to the high Q-factor of the series oscillatory circuit when extinguished lamp will be different than in the burning mode. Due to this, a higher voltage is provided on the oscillating circuit, because the generation frequency is closer to the resonant frequency of the oscillating circuit and a voltage is developed on the lamp sufficient for its ignition. However, they are initially heated by the current flowing through the filaments, and when a certain temperature is reached, the lamp is ignited. At this time, zener diodes 14 protect the transistor from overvoltage on the gate. After lighting the lamp, the Q-factor of the circuit drops, the generation conditions are fulfilled at a different frequency, and the electronic choke switches to the optimal oscillation mode of class E, which is characterized by high efficiency. In such a scheme, the efficiency-limiting factors are the proportionality of the high-frequency resistance of the inductor, the resistance of the transistor in the open state and the series active resistance in the capacitors with the equivalent load resistance of the autogenerator, approximately equal to 0.578 the ratio of the supply voltage to the consumed direct current A-0.578-(0- /-). When the supply voltage increases, the efficiency of the device increases.

Fig. 2 shows the layout of one of the device variants and the experimental dependence of the voltage on the drain of the transistor (Fig. 2a) and on the lamp (Fig. 2b) on time. The elements of the scheme were calculated according to the method of Ib| for the values of the operating resistance of a fluorescent lamp with a power of 18W (1000lm, with a power consumption at a frequency of 800KHz of about 15VЮW) of 180Ω and with a filament resistance of 3Ω in the cold state and 15-18Ω in the hot state. The ballast when operating from 128 shows 7695 efficiency, defined as the ratio of the product of the lamp current to the voltage on the lamp to the product of the current and voltage consumed from the power source. Taking into account the greater efficiency of the fluorescent lamp at a high frequency, the efficiency of the luminous flux will be higher than when powering the lamp from a source with a frequency of 50 Hz 22 V using a conventional inductive choke.

Thus, this electronic ballast can be used where high efficiency and low supply voltage play an important role: in transport, in power systems from solar batteries, in emergency lighting systems, in portable light sources. Ballast contains a minimum of parts and is easy to manufacture.

Sources of information: 1. Vaigaplade M. Eisigopis I(atr Baiiazi dezidp / Zetisopaisiog arriisaiop poie, Moiogoia, AM1543/0. -32 years - re: /Lumlu.opzeti.sot/ryb/ SoIPagegai/AM 1543-O0. ROG 2 . Ropse U., Agats 9., Aiopso .). M., Viso-Zesadez M. Eiesigopis BraiIavzi rbazei op siazz E atriyeg u a sarasiime iplepeg apa aittipud g rpoiomoigais arriisayope / Arriiei romzhmeg eiiIesigopishh, Sopiegepse apa Ekhroviop, 1998,

ARES98, Sopiegepse Rgoseyedipov 1998, Tpipeepiy Apppayi, Moi.2, 1998, R.1156-1162.

Z. Megope I. A. bipdie zulisp eiIesigopis raPavzi/ Raii. BOTH 6 144 173, SI. НО5В37/02, App. 10.11.1999, issued on 7.11.2000. 4. Bokai M. 0., Okai A. 0. Nidp-enisiepsu shpea vumyspipd romeg atriyeg. Paradise BOTH 3919656, Mom. 11, 1975. 5. Spetom O.M., Kalgitiegslyk M.K., apa Kyi2papouzki M... "Siaye86-E MO5-EET Iom/-momkade rozheg ozsiMPag,"

Rgoseyedipov o! IEEEE Ipiegpayopa! 5utrozisht op Sigsiiiyiv5 apa Zuvietv, my. 5, Rpoepikh, A7, Mau 2002, pp. 509-512. 6. Kriizhanovsky V.G., Rudyakova A.N., Chernov D.V. Methodology of development and characteristics of autogenerator class E / Technology and design in electronic equipment.-2002.-Me2.-S.9-12. (prototype) 7. Kryzhanovsky V.G., Rudyakova A.N., Chernov D.V. Design methodology and research of class E amplifier / Technology and design in electronic equipment. -2001. -Me4-5. - P.11-15. the same and K ii shchi with g nn them pry she she ny shinny: shi SY me Y p penya vy y Ah yi N ze Z N E I N 1413 | shh shhshhi : : : U Y : naEshshshshvichshni : I EM Z 16

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Fig. I

Claims (1)

An electronic ballast containing a transistor operating in a Class E autogenerator circuit, the turn of the transistor connected to the common wire, a choke connected to the drain, the other end of which is connected to the power supply, a capacitor, the other end of which is connected to the common wire , and the inductance of the series oscillating circuit, to the other end of which is connected the first capacitor of the voltage divider, to the second terminal of which is connected the second capacitor of the divider, connected to the common wire, and the inductance connected to the gate of the transistor, a resistor is also connected to the gate, with connected to the power source, a resistor connected to the common wire, and zener diodes connected to the common wire are turned on, which is characterized by the fact that a capacitor is connected to the point of connection of the inductance and the first capacitor of the divider, the second terminal of which is connected to the first terminal of the first filament of the incandescent lamp, the second terminal of this filament is connected to another capacitor , the second terminal of this capacitor is connected to the first terminal of the other filament of the lamp, the other end of the second filament is connected to the common wire, and the capacitor is connected by one terminal to the junction point of the inductance and the first capacitor of the divider, and the second terminal to the common wire.