RU1438589C - Method of ignition of discharge in gaseous-discharge gap and device for its realization - Google Patents

Abstract

FIELD: electrical engineering. SUBSTANCE: invention is aimed at increased reliability of ignition of discharge in gaseous-discharge gap by improvement of ignition of auxiliary discharge in region of arc discharge and by change of electromagnetic field in main discharge gap thanks to short-time application of difference of potentials between main electrodes. EFFECT: increased reliability of ignition of discharge. 2 cl, 2 dwg

Description

 The invention relates to the field of electrical engineering, and in particular to a method for igniting a discharge in the main discharge gap formed between two main electrodes, next to one of which there is an auxiliary electrode forming an auxiliary discharge gap with it, including gas discharge lamps with several main electrodes having auxiliary electrodes.

 The aim of the invention is to increase the reliability of ignition of the discharge in the gas discharge gap by improving the ignition of the auxiliary discharge in the region of the arc discharge and changing the electromagnetic field in the main discharge gap due to the short-term application of an additional potential difference between the main electrodes.

 In FIG. 1 shows a switch-on circuit for a gas discharge lamp with four primary and one auxiliary (igniting) electrodes, comprising a source of charging current providing pre-charging of the capacitance; in FIG. 2 the same, using a key in the auxiliary electrode circuit.

 A device for implementing the method of ignition of a lamp 1 with four main electrodes 2-5 contains inductive ballast 6-9 connected to the mains supply and a limiting ballast element 10, for example, a capacitor, in the auxiliary electrode circuit 11, the common point with the switching element 12 of which is connected to the positive the output of the charging voltage source, which includes, for example, a resistor 13 connected in series, connected to the third phase of the supply network, and a diode 14, the cathode of which is connected to this common her point. The voltage supply to the auxiliary electrode 11 is carried out using a switching element 12, for example a button.

 A phase-controlled non-linear element 15, for example, a dynistor, the cathode of which can be connected to the auxiliary electrode 11, the common point of the dynistor 10 connected to the ballast element 10, is connected to the third phase of the supply network through series connected a resistor 13 and a diode 14, the cathode of which is connected to this common point.

 The essence of the proposed method of ignition of a discharge in the main gas-discharge gap is as follows.

 By supplying the device with a voltage of the supply network, an alternating electromagnetic field with a frequency ω between the electrodes 4 and 5, forming the main discharge gap, is excited.

 By pressing the button 12, a potential difference appears between the main 5 and auxiliary 11 electrodes forming the auxiliary discharge gap, and at the moment of reaching a value equal to the ignition voltage of the auxiliary discharge, the discharge is ignited in the auxiliary discharge gap on the falling portion of its current-voltage characteristic.

When a transient process occurs in a circuit formed after ignition of an auxiliary discharge, an electromagnetic field with a frequency of ω _{sv is} excited.

The transition process occurring in the circuit after ignition of the auxiliary discharge is similar to the transition process occurring in the RLC circuit, the equivalent active resistance R _{equiv of} which determines basically the equivalent resistance of the auxiliary discharge, and the equivalent inductance L _equiv is equal to the sum of the inductances L ₈ and L _{9 of the} two windings inductive ballast.

> R свободная составляющая тока i_св носит колебательный характер и описывается уравнением:
i_cв (+) Ае^-stsin(ω_св + γ), где А и γ постоянные интегрирования;
ω_св угловая частота свободных колебаний;
ω_св=

ω_o резонансная частота;
δ коэффициент затухания.The transition process in this circuit can be of a different nature. When condition 2 is fulfilled

> R the free component of the current i _sv is oscillatory in nature and is described by the equation:
_CB i (+) Ae ^-st sin (ω _{communications} + γ), where A and γ are constants of integration;
ω _{St. the} angular frequency of free vibrations;
ω _sv =

ω _o resonant frequency;
δ attenuation coefficient.

где U_ВА мгновенное значение линейного напряжения питающей сети;
L₈ и L₉ индуктивности двух обмоток балластных элементов.In this case, the voltage between the main electrodes 4 and 5, forming the main discharge gap, takes the value:
U _4,5 = U _BA - (L ₈ + L ₉ )

where U _{VA is the} instantaneous value of the line voltage of the supply network;
L ₈ and L ₉ inductance of two windings of ballast elements.

 If the parameters of the circuit elements are selected so that the operating point is selected on the incident section of the current-voltage characteristic of the auxiliary discharge and the frequency of free oscillations exceeds the frequency of the mains, then the derivative of the auxiliary current di / dt takes a negative value at least once in half a period.

 Thereby, a voltage pulse is excited, which significantly increases the potential difference between the main electrodes and provides increased reliability of the ignition of the discharge between the main electrodes 4 and 5.

 The experimental and calculated data show that the values of the integration constants A and γ, and hence the magnitude of the voltage pulse, substantially depend on the moment of switching relative to the phase of the supply voltage at the main electrodes 4 and 5. By introducing a charging circuit consisting of a resistor 13 and a diode 14, provide a transition process not at zero initial conditions and higher stability of the reliability of ignition of the discharge between the main electrodes 4 and 5 of lamp 1.

 The introduction of a phase-controlled switching element 12 into the circuit of the ignition electrode 11 allows the beginning of the transition process not only not at zero initial conditions, but at a certain phase of the supply network.

 In this case, the value of the derivative of the auxiliary discharge current di / dt takes a negative value at the moment when the ignition voltage between the main electrodes 4 and 5 is close to the minimum, which ensures higher reliability of the ignition of the main discharge.

Analysis and statistical data processing show that it is advisable to choose the optimal values of the frequency of free oscillations of the transient process within 1.3 ≅ ω _sv ≅ 7.5ω, the ratio of the magnitude of the pulse voltage generated between the main electrodes to the linear voltage of the supply network U _them / U in between 0.29-3.1 and the value of capacitance C, for example, a capacitor included in the circuit of the ignition electrode 11 in the range: 4L / 13 ω ² ˙ L ² + R ² > C 4L / 255 ω ² ˙ L ² + R ² .

Claims (1)

1. A method of ignition of a discharge in a gas discharge gap in which an alternating electromagnetic field with a frequency ω is excited by creating a potential difference periodic with the value of the effective value U corresponding to the operating voltages between the electrodes forming the main discharge gap, characterized in that, in order to increase the reliability of ignition discharge, ignite the discharge in the auxiliary discharge gap on the falling section of its current-voltage characteristics, excite the electromagnetic field in the auxiliary Yelnia discharge gap with the _{communication} frequency w which satisfies the condition

and change the electromagnetic field in the main discharge gap by short-term application of an additional potential difference U _{and m} between the electrodes forming the main discharge gap, with a frequency ω _sv and an amplitude satisfying the condition:

2. A device for igniting a discharge in a gas-discharge gap, comprising main electrodes connected to the terminals for connecting the supply network through an inductive ballast element, between which a discharge gap is formed, an auxiliary electrode located near one of the main electrodes, forming an auxiliary discharge gap with it and connected to the other main electrode through the key and the element limiting the auxiliary discharge current, characterized in that the auxiliary current limiting A single discharge is made in the form of capacitive resistance connected to a charging voltage source, the positive output of which is connected to the common point of the element limiting the auxiliary discharge current and the key, and the negative output of the charging voltage source is connected to another output of capacitive resistance, while the value of capacitance C the specified resistance is selected from the condition:

where L is the inductance of the windings of the ballast elements;
L _{e to the} equivalent inductance of the circuit resulting from the ignition of an auxiliary discharge;
R _{e to the} equivalent active resistance of this circuit.

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