JPH0256520B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a self-excited thyristor series inverter type multiple spark ignition device.

FIG. 1 shows a conventional example of a general ignition device of this type. The details of the operation of each component with the reference numeral in this figure are the same as the component with the same reference numeral (the presence or absence of suffixes a and b does not need to be considered) in FIG. Therefore, the explanation regarding this example will be referred to.

For this type of conventional device, the basic functional requirement is to increase the discharge energy obtained in the discharge gap g as much as possible, but in addition to this, there is one practical requirement. As such, the potential system of the input AC power supply 1 in the power supply section A may be a low voltage system, for example, a 100V system, or
There is a question of whether it is possible to create a device that is suitable for a relatively high voltage system, such as a 200V system.

However, with the conventional device shown in Figure 1, it is possible to use both voltage systems reasonably without waste.
This could not be provided due to practical constraints such as the electrical characteristics, physical dimensions, and cost of each component in the operating section B. This is due to the following reasons.

The discharge energy or ignition energy obtained in the discharge gap g is proportional to the stored energy E stored in the resonant capacitor 8 in the operating section B, and this stored energy E is expressed by the following equation.

E=CV ² /2 C: capacitor capacity V: potential between capacitor electrodes Therefore, in order to increase the stored energy E, and ultimately the ignition energy, there are two methods: increasing the capacitor capacity and increasing the applied voltage. , and, of course, there are methods that combine both.

However, it is impossible to increase the capacitor capacity beyond a certain level from the practical point of view of this type of ignition device as a commercial product. The discharge current per unit discharge increases, and the current capacity of the thyristor 6 as a switching element for discharge operation, the primary winding 21 of the ignition coil, etc. must be increased, and of course, the capacitor 8 itself becomes larger, so in the end, This is because the entire device becomes significantly larger and costs increase.

Therefore, consideration regarding voltage is desirable, and furthermore, 200V drive naturally provides greater ignition energy than 100V drive. However, this time, the breakdown voltage of each component in the operating section B, the recovery time of the switching element, etc. become problems.

Of course, the thyristor 6 needs to have a high withstand voltage. For example, when considering a 200V system, a reverse voltage of about 800V is required due to the resonance voltage, and a 1KV class is required for safety. High-voltage products are not only expensive, but also have the disadvantage that the recovery time due to the carrier accumulation effect is generally several tens of microseconds, and therefore it is difficult to use a large number of discharges per unit discharge operation or unit time. It becomes impossible to do so. Therefore, even if it was possible to increase the discharge energy per discharge, the ignition energy, which is generally evaluated by the total amount of energy during a certain period of time, could not be increased. In fact, for these reasons,
This type of ignition system for 200V systems is hardly ever put into practical use.

On the other hand, let us assume that the operating part B is made for a 200V system using the conventional configuration shown in the first figure, even though it has the above-mentioned drawbacks. Then, as it is,
It turns out that simply changing power supply 1 to 100V in response to the previous request, considering the application of a 100V system, would be extremely wasteful. In other words, from the above formula, simply speaking, there is the disadvantage that the ignition energy is reduced to 1/4, and the withstand voltage of thyristor 6 is the same as using one that is unnecessarily large. It is.

As described above, the present invention solves the complicated drawbacks of existing ignition devices of this type and provides a self-excited thyristor series inverter type multiple spark ignition device that satisfies the following requirements (i) and (ii). This is what we intend to provide.

(i) Even if it is a relatively high voltage system such as an AC 200V system, the advantage of increasing capacitor storage energy due to the high voltage system can be fully exploited without reducing the number of discharges per single operation. To be able to do it.

(ii) Power supply section A as a relatively low voltage system
To make it possible to use an actuating part B, which has a function satisfactory as a 200V system as described above, without waste and without energy loss even when a 100V system is used.

Also, considering the main objectives (i) and (ii),
If it is satisfactory for a 200V system, and if 100V drive is also acceptable, it is necessary to be able to use it even when a 200V system is applied, that is, to be able to select and use different potential systems. It has as a purpose.

Embodiments of the present invention will be described below with reference to FIG.

First, in the actuating section B, the thyristor part of the series inverter circuit is constituted by a series circuit of a plurality of individual thyristors (in this embodiment, two thyristors 6a and 6b), and each thyristor has its own dedicated thyristor. The gate circuits (two, 28a and 28b) are simultaneously triggered. In this way, the reverse breakdown voltage of each thyristor can be reduced to one-half of the total number of thyristors, and since such a thyristor has a short recovery time, it is possible to maintain a large number of repeated spark discharges.

As will be explained in detail below, each dedicated gate circuit 2
Each of the gate circuits 8a and 28b may be similar to the conventional gate circuit 28 shown in FIG. 1, or any other existing circuit configuration may be used, and the one shown is only one example.

In the case shown in the second diagram, the low voltage system power supply 1 described later
L is shown as a solid line. First, in order to prove that the above-mentioned configuration operates in a high voltage system such as a 200V system, the corresponding power input terminals 34 and 32 of the input section consisting of the choke coil 3 and capacitor 4 are connected. 200V
The operation when a high-voltage power supply 1H (virtual line) such as the following is connected will be explained.

First, during the positive half cycle of the power supply 1H, the resistor 2, resistors 7a and 7b are connected from the power supply line 1a.
The capacitors 14a, 14b are charged through the capacitors 14a, 14b, and when the charging voltage reaches the threshold voltage or breakover voltage of the appropriate switching element 13a, 13b, this switching element becomes conductive.
The capacitor 14a, via the resistors 9a, 9b,
The charge charged in thyristor 14b is discharged to the gates of thyristors 6a and 6b, and is used as a trigger current.

When the thyristors 6a and 6b become conductive at the same time, the resonant inductor 5, the thyristor 6a,
6b, the resonant capacitor 8, the power supply line 1b, and the resonant capacitor 8 is charged. This charging current oscillates due to the resonance of the resonant inductor 5 and the resonant capacitor 8, and when the charging current is reversed, the thyristors 6a and 6b are turned off because they are in opposite directions. Then, the charge stored in the resonant capacitor 8 is transferred to the primary winding 2 of the ignition coil.
1, a high voltage is generated in the secondary winding 23, and a spark discharge occurs in the discharge gap g. at the same time,
Ignition coil feedback winding or tertiary winding 2
2a and 22b include the + shown in the figure with respect to the primary winding.
A voltage is generated with the - polarity, but at this time, this voltage is short-circuited by the Zener diodes 18a, 18b via the resistors 16a, 16b, so that it does not affect the gates of the thyristors 6a, 6b. And again, at this point, the previous capacitors 14a, 1
4b is reliably reset (charge discharged) by turning on the reset transistors 17a and 17b.

Next, due to the resonance between the resonant capacitor 8 and the primary winding 21, the resonant current is reversed and voltages with (+) and (-) polarities are generated in the primary winding as shown in the figure. While a high voltage is generated in the wire 23 and a spark discharge occurs in the discharge electrode g, a voltage is also generated in the tertiary windings 22a and 22b with the polarities (+) and (-) shown in the figure, and the diodes 11a and 11b and the capacitor 15a, 15b, resistors 16a, 16b, the illustrated polarity is (+), (-) is the capacitor 15a, 1.
Charge the 5b. When the voltage of the tertiary winding becomes zero, the charge accumulated in the capacitors 15a and 15b flows into the gates of the thyristors 6a and 6b via the resistors 9a and 9b.
Turn this on. This operation is repeated thereafter.

In this embodiment, a series circuit of a resistor 24a and a capacitor 25a and a resistor 26a are connected to the first thyristor 6a, and a series circuit of a resistor 24b and a capacitor 25b and a resistor 26b are connected to the second thyristor 6b. Since the surge absorption/balance circuits 27a and 27b are placed in parallel, the resonant voltages of the resonant capacitor 8 and resonant inductor 5 can be made equal even if there is a slight difference in characteristics between the two thyristors 6a and 6b used. This eliminates the inconvenience of applying a high reverse voltage to only one thyristor.

In this way, a plurality of thyristors (two in the illustrated embodiment, but three or more can also be used)
The same number of gate circuits 2 are connected in series and separated independently.
8a, 28b, . . . each corresponding thyristor 6
If a, 6b, ... are triggered at the same time to cause self-oscillation, even if the power supply voltage is high and the resonance voltage is high, for example, even if the power supply voltage is 200V and the resonance voltage is 800V in the previous example, each Thyristor 6
For a and 6b, it is possible to use a high-speed thyristor with a low withstand voltage such as 500V and a turn-off time of several μs or less, which allows for a large number of discharge repetitions, which eliminates the disadvantages of using conventional large-capacity capacitors. Therefore, a large amount of ignition energy can be obtained.

Next, in accordance with the object (ii) of the present invention, if such an excellent device that can be used in a high voltage system and has no problem with recovery time can be provided, it can be used in a low voltage system, for example.
Measures will be taken to enable effective use even in 100V systems.

In short, a half-wave voltage doubler circuit 35 is provided at the front stage,
A low voltage power source 1L is connected to the input terminals 31 and 32 (terminal 32 may be common to the ground line 1b), and output terminals 33 and 32 are connected to the high voltage input terminals 34 and 32. Similarly, since the terminal 32 may be a ground bus, the connection between the terminals 33 and 34 is actually made via the connection line 36 shown as a virtual line.

In this embodiment, the voltage doubler number n of the half-wave voltage doubler circuit is 2, and the half-wave voltage doubler circuit itself has an existing configuration including a capacitor 29 and a diode 30.

In the above operation, if you set the high voltage system to 200V,
Since the potentials supplied to the actuating part B are almost the same, similar operations can be expected.

That is, the input terminals 31 and 32 of the half-wave voltage doubler circuit 35
When 100V AC is applied between them, during the negative half cycle, especially during the 1/4 cycle, the capacitor 29 in the path of terminal 32, diode 30, capacitor 29, and terminal 31 becomes -, + in the figure. This is because when the power supply is reversed, this capacitor potential is superimposed on the power supply potential as shown in the figure, and approximately the same potential as the 200V system is generated between the power supply lines 1a and 1b.

After all, according to the present invention, even if it is a 100V system,
This means that the operating part B, which can be assembled as a 200V system, can be operated without any waste.

Furthermore, as is clearly seen from the above explanation and FIG.
You can choose between 100V and 200V.
In other words, if the terminals 31 to 34 (middle terminal and terminal 32 are the common terminal) are placed in a position where the user can easily operate the device, when the user wants to use the 100V system, the terminals 33 and 34 can be connected with the jumper 36. In the above, it is sufficient to connect the relevant power supply 1L between terminals 31 and 32, or if you want to use a 200V system, connect terminals 33 and 34.
Connect the power supply 1 between terminals 34 and 32 with the terminals 34 and 32 open.
All you have to do is connect H.

As detailed above, according to the present invention, as this type of ignition device for high voltage systems such as 200V systems, which had many problems in the past, the drawbacks have been eliminated and the advantages of high potential have been brought out. This provides an extremely useful and rational ignition device that can be driven without waste even with a low voltage system such as a 100V system, and it also makes it possible to rationally select and use both voltage systems. This can have extremely significant effects.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an example of a conventional self-excited thyristor series inverter type multiple spark ignition device, and FIG. 2 is a schematic diagram of an embodiment of the present invention. In the figure, 1, 1L, 1H are AC power supplies, 5 is a resonant inductor, 6, 6a, 6b are thyristors, 8 is a resonant capacitor, 21 is an ignition coil primary winding, 23 is a secondary winding, 27a, 27b is a surge absorption and balance circuit, 28, 28a, 28
b is a thyristor trigger gate circuit, 35 is a half-wave voltage doubler circuit, and 31 to 34 are terminals.

Claims (1)

[Scope of Claims] 1 Self-excitation in which a thyristor series inverter circuit is caused to self-oscillate using an ignition coil as a load, and a plurality of sparks are caused to fly between discharge electrodes using a high voltage generated on the secondary side of the ignition coil. In a thyristor series inverter type multiple spark ignition device, the thyristor in the thyristor series inverter circuit is configured by connecting multiple individual thyristors in series, and each thyristor is simultaneously triggered by a dedicated gate circuit for each thyristor to generate self-oscillation. At the same time, a half-wave voltage doubler circuit is provided in front of the AC power input terminal, the output terminal of the half-wave voltage doubler circuit is connected to the AC power input terminal, and the power source is connected to the input terminal of the half-wave voltage doubler circuit. A multi-spark ignition device characterized by connecting. 2 Self-excited thyristor series inverter type multiple sparks in which a thyristor series inverter circuit is self-excited to oscillate with an ignition coil as a load, and multiple sparks are sent between discharge electrodes using the high voltage generated on the secondary side of the ignition coil. In the ignition device, the thyristor in the thyristor series inverter circuit is configured by connecting a plurality of individual thyristors in series, each thyristor is triggered simultaneously by a gate circuit dedicated to each thyristor to cause self-oscillation, and an AC power source is used. A multi-spark ignition device characterized in that a half-wave voltage doubler circuit is provided upstream of the input terminal, and an output terminal of the half-wave voltage doubler circuit is removably connected to the AC power input terminal.