RU94965U1 - GAS DISCHARGE POWER SUPPLY DEVICE - Google Patents

Abstract

 1. The power supply device for a gas-discharge ozonizer, consisting of a barrier discharger, a high voltage transformer, a capacitor in the primary circuit of the transformer, a transistor switch and a transistor switch control unit in frequency and duration of the start pulses, characterized in that the period of natural oscillations of the circuit formed by the high voltage winding and capacitance spark gap, is in the range of 1-4 characteristic times of gas-discharge processes in the barrier spark gap, period of natural oscillations the circuit formed by the primary winding of the transformer and the capacitor in the primary winding circuit can differ by no more than 25% from the period of natural oscillations of the circuit formed by the high-voltage winding and the capacitance of the spark gap, the primary winding of the transformer is shunted to meet the power supply by the thyristor, containing the thyristor control pulse generator in the key circuit , the duration of the pulses for opening the transistor switch lies in the range from 0.5 μs to 1/4 of the period of natural oscillations of the circuit formed by the primary transformer winding and capacitor in the primary circuit. ! 2. The power supply device of the gas-discharge ozonizer according to claim 1, characterized in that more than one transistor switch with time-apart opening pulses of these keys spaced apart in parallel to the transformer primary can be connected. ! 3. The gas discharge ozonator power supply device according to claim 1, characterized in that the capacitor in the primary winding of the transformer can be connected to the primary winding both in parallel and in series.

Description

The utility model relates to devices for producing ozone from oxygen-containing gas in an electric gas discharge at a dielectric barrier and can be used to create disinfection and purification plants for water and air.

The well-known "INSTALLATION FOR OZONE PRODUCTION" according to the patent of the Russian Federation for invention No. 2114053, class СВВ 13/11, 01/06/1997. The installation contains an ozone generator and a high voltage power source. The high-voltage power supply includes a rectifier, consisting of 2 diodes connected by a half-wave rectification circuit and a smoothing capacitor connected between the terminals of the rectifier. One of the external voltage supply leads a rectifier capacitor with a leakage resistor in front of the rectifier. The high voltage power supply also includes a high voltage transformer and a blocking generator. One output of the rectifier is connected to one of the terminals of the primary winding of the high-voltage transformer, another output is connected to another terminal of the primary winding of the high-voltage transformer through a blocking generator, which is equipped with positive feedback from the primary winding of the high-voltage transformer.

The disadvantages of the device are:

The lack of coordination, leading to an underestimated ozone output, of the intrinsic time characteristics of the oscillatory circuit formed by the inductance of the output winding of the high voltage transformer and the capacity of the ozone generator, with characteristic times of gas-discharge processes in the ozone generator.

The presence of residual electrical oscillations in a transformer with an output amplitude below the ionization voltage in the gas gaps of the arrester and leading to unproductive heat losses on the resistive elements of the electrical circuits.

Temperature instability of the device.

The well-known "WIDE OZONE GENERATOR" according to the patent of the Russian Federation for invention No. 2193521, class СВВ 13/11, 06/20/2000, which includes a constant voltage source, high voltage transformer, storage capacitor connected in series with the transformer primary winding, and a discharge device, parallel to the secondary winding of the transformer. The positive potential of the DC voltage source is supplied to the storage capacitor through the inductor and diode connected in series, and the minus of the power source is connected to the free terminal of the transformer primary winding. The excitation of electrical oscillations in the circuit is carried out using a thyristor connected in parallel with the storage capacitor and the primary winding of the transformer, in the direction from plus to minus the voltage source, and the thyristor switch circuit has a thyristor control circuit.

The disadvantages of the device are:

Lack of coordination of the own time characteristics of the oscillating circuit formed by the inductance of the output winding of the high voltage transformer and the capacity of the ozone generator with the characteristic times of gas-discharge processes in the ozone generator.

The presence of residual electrical oscillations in the transformer with an output amplitude below the ionization voltage in the gas gaps of the spark gap.

Low response speed of the key element (thyristor), leading to a decrease in ozone output and an increase in heat loss at the key element.

It is known "DEVICE FOR OZONE GENERATION USING PULSE BARRIER DISCHARGE" according to the patent of the Russian Federation for invention No. 2357921, class С01В 13/11, 07/07/2007, containing a source of high voltage pulses, supplying a high-voltage transformer and a discharge chamber connected to the terminals of the high-voltage winding . Moreover, the high voltage source ignites the barrier discharge with pulses of asymmetric shape, the maximum amplitude of the negative part of which is at least two times the maximum amplitude of its positive part.

The disadvantages of the device are:

Lack of coordination of the own time characteristics of the oscillating circuit formed by the inductance of the output winding of the high voltage transformer and the capacity of the ozone generator with the characteristic times of gas-discharge processes in the ozone generator.

The presence of residual electrical oscillations in the transformer with an output amplitude below the ionization voltage in the gas gaps of the spark gap.

It is known "DEVICE FOR OZONE GENERATION USING PULSE BARRIER DISCHARGE" according to the patent of the Russian Federation for invention No. 2363653, class С01В 13/11, 10/29/2007, consisting of a discharge chamber, a pulse transformer with one high-voltage winding and with one or more primary windings. Each primary winding is connected in series with one of the storage capacitors. The output circuit is formed by a high voltage winding and electrodes of the discharge chamber. The oscillations in the input circuits are excited from a high voltage pulse source containing a control pulse generator, as well as an autonomous charger for each input circuit and a controlled pulse switch shorted by a pulse capacitor.

The disadvantages of the device are:

Lack of coordination of the own time characteristics of the oscillating circuit formed by the inductance of the output winding of the high voltage transformer and the capacity of the ozone generator with the characteristic times of gas-discharge processes in the ozone generator.

The presence of residual electrical oscillations in the transformer with an output amplitude below the ionization voltage in the gas gaps of the spark gap.

The temperature instability of the device due to the presence of several input circuits interacting with each other through the inductance of the high voltage winding.

Common in the above analogues is that the energy from the power source to the arrester is transmitted by at least two connected electromagnetic circuits and is accompanied by damped oscillations of their own for each circuit. Moreover, only the first, from the moment of excitation, period of oscillations is practically involved in the formation of ozone. The rest of the oscillations are dissipated in the form of heat on the passive elements of the circuits.

It is also known that due to problems of heat removal from the discharge zone, the repetition rate of triggering pulses, especially for simple ozone generators of low and medium productivity, is usually significantly lower than the natural frequency of the energy-transferring circuits. Consequently, large heat losses, not accompanied by the formation of ozone, are inevitable for such devices.

In the presence of special measures for cooling the elements, the analogs can work at starting frequencies close to the natural frequencies of the transmitting circuits, but at the same time the starting pulses are superimposed on the natural oscillations of the circuits. Therefore, stable and reliable operation of the ozone generator is possible only if there is synchronization of triggering pulses with natural oscillations of the circuits and additional measures are taken to compensate for temperature changes in electrical parameters, which significantly complicates the product.

It is known (Theory of circuits and signals, analysis methods, Yu. Novikov, 2005) that the efficiency of energy transfer by coupled circuits depends on the degree to which the electrical parameters of the circuits are consistent with each other and with the load characteristics. For example, the equality of the natural frequencies of the input and output circuits of a high-voltage transformer provides a resonant (maximum) energy transfer to the discharge gap.

In turn, with a half-width of self-oscillations in the output circuit close to the recharge time of the dielectric barrier in the gas gap, the maximum specific ozone yield takes place. On the contrary, a significant difference in the half-width of self-oscillations in the output circuit from the time of recharging the barrier sharply reduces the output characteristics of the ozonizer, and in some cases, for example, if the half-width of self-oscillations in the output circuit is too large, the amplitude of the reverse pulses can exceed the breakdown voltage of the transformer windings. The adjustment of the frequency and duration of pulses, provided in some well-known analogues, in the vast majority of cases, is not able to provide maximum output characteristics of the ozonizer.

As a prototype, "OZONE GENERATOR POWER SUPPLY DEVICE" was selected according to the patent of the Russian Federation for invention No. 2263628, class СВВ 13/11, 12/15/2003. The power supply device of the ozone generator contains a high-voltage pulse transformer and a storage tank installed in series with the primary winding of the transformer. Parallel to the primary winding and the storage capacitance, a diode and a dynistor (or thyristor in the dynistor mode) are connected in mutually opposite directions. In series, an additional capacity is connected to the storage capacity, one lining of which is a terminal for connection to the electric network. An ozone generator is connected to the terminals of the secondary winding of the high voltage pulse transformer.

The disadvantages of the device are:

Lack of coordination of the own time characteristics of the oscillating circuit formed by the inductance of the output winding of the high voltage transformer and the capacity of the ozone generator with the characteristic times of gas-discharge processes in the ozone generator.

Low response speed of the key element (thyristor).

In the prototype, the presence of a reverse diode provides suppression of self-oscillations in the circuit, except for the first half-wave from the moment the thyristor is turned on, minimizing passive energy losses. However, it is known (patent of the Russian Federation for invention No. 2357921, class СВВ 13/11, 2007) that ozone is most effectively formed in the second half-wave of excited oscillations. This means that in the prototype the ozone output is significantly underestimated compared to a device without a reverse diode.

Utility Model Task:

Decrease in heat losses in the ozone generator;

The increase in the specific yield of ozone for a given device size;

Improving the reliability and stability of the ozone generator.

The technical result of the utility model is achieved:

By installing parallel to the input winding 3 of the thyristor transformer 5 towards the plus of the voltage source, with the thyristor shunting turned on no earlier than the second, from the moment of opening the transistor switch 7, half-waves of self-oscillations in the circuit formed by the transformer winding 3 and the capacitor 4 (Fig. 1.2) ;

The choice of parameters of the output (high voltage) winding of the transformer 2 from the condition for finding the period of natural oscillations of the circuit formed by the inductance of this winding and the capacity of the discharge device 1 in the range from 1 to 4 characteristic times of recharging of dielectric barriers in the gas gaps of the discharge device 1;

By choosing the capacitor 4 capacitance in the input winding 3 circuit (Fig. 1, 2) from the condition that the natural frequency of the circuit formed by the inductance of this winding and the capacitance 4 does not differ by more than 25% from the natural frequency of the circuit formed by the winding 2 inductance and capacitance bit device 1;

By setting the pulse width of the opening of the transistor switch 7 in the range from 0.1 μs to 1/4 of the period of self-oscillation of the circuit formed by the inductance of the winding 3 and the capacitance of the capacitor 4;

Parallel connection of one or more transistor switches 7 to an existing switch 7 (Fig. 3) with disparate openings of these switches;

The power supply device consists of the following parts:

A gas-discharge device 1 assembled from electrodes and dielectric layers between them, which are installed with the formation of gaps (Fig. 1.2).

High-voltage winding 2 of the transformer with leads to the electrodes of the discharge device 1 (Fig. 1,2). In this case, the winding 2 and the electrodes of the discharge device 1 form an output oscillating circuit with a period of natural oscillations where L1 is the inductance of the winding 2, and C1 is the capacity of the discharge device. The number of turns of winding 2 is selected from the condition that T1 is in the range from 1 to 4 characteristic times of recharging of the dielectric layers in the gas gaps of the discharge device 1.

Primary winding 3 of the transformer connected by one of the terminals with the plus of the DC voltage source either directly (Fig. 1) or through a diode (Fig. 2). The number of turns of the winding 3 is determined by the transformation coefficient necessary to create a voltage, ionizing gas, in the gaps of the discharge device 1.

A capacitor 4 connected to winding 3 is either parallel to the terminals of winding 3 (Fig. 1) or sequentially between the output associated with the plus of the voltage source and the minus of this source (Fig. 2). In this case, the winding 3 with inductance L2 and the capacitor 4 with the capacitance C2 form an input oscillating circuit (parallel and, accordingly, serial) with a period of natural oscillations The value of the capacitance C2 of the capacitor 4 is selected from the condition that T2 differs from T1 by no more than 25%.

Thyristor 5 connected in parallel to the input winding 3 of the transformer towards the plus of the voltage source (Fig. 1, 2).

Shaper of control pulses of thyristor 6 with an output connected to the key of thyristor 5 (Fig. 1, 2). The pulse shaper 6 is synchronized with the control pulses of the transistor switches 7 with a delay relative to these pulses in the range from 0.5 to 8 periods T2.

One (Fig. 1, 2) or several (Fig. 3) transistor switches 7 connected by a power input to the plus of the voltage source through the winding 3 of the transformer, and by a power output to the minus of the voltage source.

One (Fig. 1, 2) or several (Fig. 3) shapers of control keys 8 connected to the control input of transistor switch 7, individual for each shaper. Shapers of control pulses of keys 8 are equipped with adjustable duration of control pulses in the range from 0.1 μs to 1/4 of period T2.

The master oscillator 9 (Fig. 1, 2, 3), with the output connected to the synchronization input of the thyristor 6 control pulse shaper. The output of the master oscillator is also connected to the input of the key control pulse shapers 8 in versions with one transistor key 7 (Fig. 1, 2) directly, and in the variant with several keys 7 through a time separator of signals 10, for example, a decimal counter with a decoder. The master oscillator 9 is equipped with a means for adjusting the frequency of the pulse generation.

The time signal separator of the master oscillator 10 (Fig. 3), for example, a decimal counter with a decoder, the outputs of which are connected to the inputs of the pulse shapers of the key control 8, individual for each output of the time separator 10.

The device operates as follows:

In the initial state, the voltage of positive polarity from a constant voltage source, for example, a rectifier or a battery, is supplied either through winding 3 (Fig. 1) or through a diode and winding 3 (Fig. 2) to the power inputs of transistor switches 7. In this case capacitor 4 in the variant (Fig. 1) is discharged, and in the variant (Fig. 2) it is charged to the supply voltage.

The signal sequence of the master oscillator 9 (Fig. 1, 2, 3) is fed to the inputs of the pulse shapers of the key control 8 in the variants with one transistor switch 7 (Fig. 1, 2) directly, and in the variant with several keys 7 (Fig. 3) through the time separator of the signals of the master oscillator 10. The time separator of signals 10 distributes a group of successive signals of the master oscillator in an amount equal to the number of transistor switches 7 to different outputs of the signal splitter, from which, in turn, the signals are fed to the moves of the corresponding pulse shapers 8. Next, the process of temporary separation is cyclically repeated.

In the key control pulse shaper 8, the signals of the master oscillator are converted into rectangular pulses with an amplitude that provides the key mode of operation of the transistor and the duration determined by the adjustment. The appearance of the pulse of the driver at the control input of the corresponding transistor key 7 causes the opening of this key. The claimed adjustment range of the key control pulse 8 duration from 0.1 μs to 1/4 of the T2 period corresponds to the beginning of the formation of ions in the gas of the discharge gaps with a pulse duration of 0.1 μs and the maximum energy transfer to the discharge device 1 with a pulse duration of 1/4 part from period T2.

Opening the transistor switch 7 leads to the appearance of electric current through the circuit from the power source through the winding 3 of the transformer and the key 7 to the minus of the power source and the transmission of electric energy through the transformer to the high voltage winding 2, charging the capacitance C1 of the discharge device 1 to the gas ionization voltage in the gaps of the discharge device . At the same time, in the variant (Fig. 1), charging occurs through the key 7, and in the variant (Fig. 2), the discharge through the winding 3 and the key 7 of the capacitor 4 is discharged. In this case, conditions arise for self-oscillations of the input L2C2 and output L1C1 transformer circuits.

If the eigenfrequencies of the input and output circuits of the transformer are equal, the phases of the voltages, respectively currents, in the circuits coincide. That is, there is a condition for maximum transfer of energy to the discharge device. As the loops mismatch, an equivalent amount of energy is transferred to the discharge device with increasing currents in the input circuit, and when the resonant frequencies of the coupled loops differ by 25% or more, the appearance of a gas discharge practically reduces to zero.

The minimum voltage at the power input of key 7 corresponds to the full charge (Fig. 1) or full discharge (Fig. 2) of capacitor 4 and the beginning of recharging of this capacitor in the input oscillatory circuit, that is, a change in the direction of self-oscillations in the circuits when the open state of key 7 stops transfer energy to a discharge device. This time interval from the opening of the key 7 to the beginning of the change in the direction of oscillation in the circuits corresponds to 1/4 of the self-oscillation period of the input circuit and determines the upper value of the range of durations of the pulse control keys 7.

In the first half-period of oscillations from the moment the key 7 was opened, despite the presence of voltage on the electrodes of the discharge device, due to the effect of electron sticking during the discharge in the electronegative gas (oxygen), ozone formation is low, but the gas medium is saturated mainly with heavy negative ions oxygen, relatively slowly charging the capacitance C1 of the discharge device 1 (Raiser Yu.P. Gas Discharge Physics, Chap. Ed. Phys.Mat.Lit, 1992).

In the second half-cycle of oscillations, when the reverse voltage reaches the ionizing value, the electrons break off from negative ions and the intense formation of electron avalanches, which are the main source of ozone formation. The increased level of ozone formation in the second half-cycle of oscillations is confirmed experimentally (patent of the Russian Federation No. 2114053, class С01В 13/11, 1997). Moreover, light electrons, recharging the capacitance of a spark gap, move orders of magnitude faster than heavy ions and create a significantly shorter and more powerful current pulse in the secondary circuit L1C1. In other words, avalanche electrons create orders of magnitude faster in the volume of gas gaps of the discharge device an electric field opposite to the voltage applied to the electrodes of the spark gap and limiting the current through the winding 2 of the transformer. In this case, the inductance of winding 2 prevents the current from decreasing in it by an additional increase in voltage at the ends of this winding with the formation of new electronic avalanches in gas gaps, up to the inversion of the oscillatory process. The upper limit of the inductance of the secondary winding 2 condition value of the order of 4 characteristic times of recharging of the dielectric barrier in the gas gap of the discharge device 1 is sufficient to complete the gas discharge processes and necessary to maintain the insulation of the transformer windings.

It is obvious that the gas flow through the discharge gaps takes the electronegative ions formed in the first half-period beyond the limits of the gaps and, therefore, removes them from participation in the formation of electron avalanches in the second half-period. Thus, the claimed restriction on the period of oscillations of the output oscillatory is optimal for the most effective formation of ozone.

The choice of the inductance L1 of the high-voltage winding 2 of the transformer from the conditions for finding the period T1 of the self-oscillations of the circuit formed by this winding and the capacitance C1 of the discharge device 1 in the range close to the characteristic time of the discharge pulse in the gas gap taking into account the two-stage discharge mechanism in electronegative gases also allows optimizing the size of the transformer for maximum ozone output.

The choice of capacitor C2 of capacitor 4 in the input winding circuit 3 of the transformer with inductance L2 from the condition that the period T2 of the oscillations of the circuit formed by this winding and the capacitor differs by no more than 25% from the period of oscillations T1 oscillations allows the transformer to be in phase with respect to voltage and current. This ensures high stability and reliability of the ozone generator.

Prior to the arrival of the next control pulse of transistor switch 7, damped self-oscillations occur in both circuits L1C1 and L2C2, in which ozone is effectively formed only in the first oscillation period from the moment of operation of transistor switch 7. The rest of the energy (about 80%) stored in the circuits, due to the lack of voltage for ionizing the gas gap, is dissipated in the form of heat on the passive elements of the circuits.

The damped oscillations in the circuits are damped by shunting the input winding 3 of the transformer with thyristor 5 (Fig. 1, 2). In this case, the signal from the master oscillator 9 is input to the thyristor 6 key control pulse generator and, after an appropriate delay and amplitude and duration formation, turns on the thyristor 6, interrupting the oscillations of the circuits and returning most of the unused energy to either the power source (Fig. 1) or capacitor 4 (Fig. 2). The claimed adjustment of the damping pulse delay relative to the key control pulses 7 in the range from 0.5 to 8 T2 periods covers the condition when the thyristor is in diode mode, and the condition of repeated repetition of gas ionization processes from one key control pulse 7, with a significant excess of the energy transferred to one pulse through a transformer over the energy consumed in the same pulse by a discharge device.

Thus, the elimination of heat losses that are not associated with the formation of ozone is achieved, which allows to increase the operating frequency of the master oscillator 9 with a corresponding increase in the productivity of the ozone generator.

The combination of the above factors results in an increase in the specific yield of ozone for a given device size, as well as an increase in the reliability and stability of the ozone generator.

In a circuit with a parallel connection of one or more transistor switches 7 with transistor switch open pulses that do not coincide in time (Fig. 3), the control pulse repetition rate per separate transistor switch decreases in proportion to the number of transistor switches 7. It is known that a permissible single value of the current through a transistor, as a rule, is much more current at a high frequency of its operation. When setting the number of transistor switches sufficient for a single-pulse mode, powerful ozone generators can be obtained that traditionally use unregulated thyristor switches with a high transmission current, but with a low response speed and lack of regulation.

Claims (3)

1. The power supply device for a gas-discharge ozonizer, consisting of a barrier discharger, a high voltage transformer, a capacitor in the primary circuit of the transformer, a transistor switch and a transistor switch control unit in frequency and duration of the start pulses, characterized in that the period of natural oscillations of the circuit formed by the high voltage winding and capacitance spark gap, is in the range of 1-4 characteristic times of gas-discharge processes in the barrier spark gap, period of natural oscillations the circuit formed by the primary winding of the transformer and the capacitor in the primary winding circuit can differ by no more than 25% from the period of natural oscillations of the circuit formed by the high-voltage winding and the capacitance of the arrester, the primary winding of the transformer is shunted to meet the supply of the thyristor, containing the thyristor control pulse generator in the key circuit , the duration of the pulses for opening the transistor switch lies in the range from 0.5 μs to 1/4 of the period of natural oscillations of the circuit formed by the primary transformer winding and capacitor in the primary circuit. 2. The power supply device of the gas-discharge ozonizer according to claim 1, characterized in that more than one transistor switch with time-apart opening pulses of these keys spaced apart in parallel to the transformer primary can be connected. 3. The power supply device of the gas discharge ozonizer according to claim 1, characterized in that the capacitor in the primary circuit of the transformer can be connected to the primary winding both in parallel and in series.