JP2627633B2 - ON / OFF detection circuit - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an on / off detection circuit for detecting on / off of a controllable switching means.

For example, the present invention provides a method for controlling two of the controllable switching means that short-circuit the power supply when turned on at the same time so as to prevent the other one from being turned off as long as one of them is on, or It is used when the control of another predetermined controllable switching means is turned on as soon as the turn-off of the predetermined controllable switching means is detected.

Accordingly, the present invention provides a circuit or device using controllable switching means, a power conversion device or a device using a power conversion circuit, for example, an ignition device including an ignition device for an internal combustion engine,
Used for high voltage generators, ozonizers, discharge lamp lighting devices, induction heating devices, etc.

2. Description of the Related Art Several examples of a conventional on / off detection circuit are disclosed by the present inventors in Japanese Patent Application Laid-Open No. 62-5019. Fig. 2 (a),
(B) (current detection means is not shown).

In either case, during the ON period of the thyristor 5,
A loop through which current flows through the resistor 2, the diode 3, and the thyristor 5 is formed.

However, the magnitude of the current must be smaller than the holding current of the thyristor 5 so that this current does not prevent the thyristor 5 from being turned off. However, in the case of impulse commutation, or when using a self-extinguishing type switching means instead of the thyristor 5, it is not necessary to do so.

If the current of each resistor 2 is detected, the on / off state of each thyristor 5 can be known.

Since the current in the direction of the diode 3 only needs to be detected, the diode 3 may be omitted. However, the diode 3 prevents unnecessary current from flowing from the diode 4 toward the DC power supply 1. On the other hand, the current of the resistor 2 is
Prevent from flowing toward. The one in which the diode 4 and the thyristor 5 are connected in series can be used as a unidirectional controllable switch.

However, in this prior art, FIG.
When these are connected in the direction of the polarity of the DC power supply 1 and the direction of the diode 4 and the thyristor 5 shown in FIG.
The circuit of (b) cannot be used.

That is, in either of the circuits shown in FIGS. 2A and 2B, a unidirectional controllable switching means in which a diode 4 (non-controllable switching means) and a thyristor 5 (controllable switching means) are connected in series is used. Although connected in the forward direction with respect to the voltage of the DC power supply 1, FIG.
When the one-way controllable switching means is connected in the opposite direction to the voltage of the DC power supply 1 as in each circuit of (b), both circuits of FIGS. 2 (a) and (b) are useful. On and off cannot be detected.

Therefore, the unidirectional controllable switching means in which the controllable switching means and the non-controllable switching means for detecting the on / off state are connected in series is connected in the opposite direction to the voltage of the power supply means used for the on / off detection. The conventional on / off detection circuit has a problem that it cannot detect on / off when connected.

(Problem) Further, this problem is caused by the fact that only the circuit shown in FIG. 2 (a) or (b) constitutes a pair of arms as shown in FIGS. 4 to 7 (current detecting means is not shown). In this case, two or four DC power supplies (power supply means) are required.

Therefore, the present invention provides a unidirectional controllable switching means in which a controllable switching means and an uncontrollable switching means for detecting ON and OFF are connected in series with respect to a voltage of a power supply means used for ON / OFF detection. It is an object of the present invention to provide an on / off detection circuit capable of detecting on / off when connected in the reverse direction.

(Object of the Invention) Such an on / off detection circuit can be complementary to a conventional on / off detection circuit, and when they are assembled together, the number of power supply means required for the detection can be reduced.

DISCLOSURE OF THE INVENTION That is, the present invention provides a first controllable switching means and a first controllable switching means.
The second non-controllable switching means is connected in anti-parallel to the first unidirectional controllable switching means in which the non-controllable switching means are connected in series, and is connected in parallel to the first non-controllable switching means. A first current flowing through the first controllable switching means in the same direction as a forward direction of the first unidirectional controllable switching means when the first controllable switching means is on; An on / off detection circuit comprising: a current path unit; and a first current detection unit for detecting the first current.

Thereby, the first unidirectional controllable switching means in which the first controllable switching means and the first non-controllable switching means are connected in series is included in the first current path means, The on / off state of the first controllable switching means can be determined from the output signal of the first current detection means, despite being connected in the opposite direction to the voltage of the power supply means used for on / off detection. .

(Effect) Further, this effect can be obtained by compensating the present invention with a conventional on / off detection circuit, and by combining the present invention with the present invention, the number of power supply means required for the detection can be reduced. , Which leads to the effect.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram showing one embodiment of the present invention.

FIGS. 2A and 2B are circuit diagrams each showing a part of a conventional on / off detection circuit.

FIGS. 3 (a) and 3 (b) are explanatory diagrams for explaining the problems of the prior art.

Each of FIGS. 4 to 7 is a circuit diagram showing one arm pair formed by the circuits of FIGS. 2 (a) and 2 (b).

8 (a) and 8 (b) are circuit diagrams each showing one embodiment of a part of the present invention.

Each of FIGS. 11 to 17 is a circuit diagram showing one embodiment of the present invention.

FIG. 18 is a circuit diagram showing an embodiment of the present invention and an arm pair using the same.

FIG. 19 is a circuit diagram showing an embodiment of the present invention and an AC-AC converter circuit using the same.

FIG. 20 is a circuit diagram showing an embodiment for forming an arm pair and an associated circuit.

21 and 22 are a left half and a right half of a circuit diagram showing an embodiment of the present invention and a circuit of an ignition device using the same, respectively.

23 and 24 are a left half and a right half of a circuit diagram showing an embodiment of the present invention and a circuit of an ignition device using the same.

FIG. 25 and FIG. 26 are a left half and a right half of a circuit diagram showing two embodiments of the present invention and an AC-AC converter circuit using them.

BEST MODE FOR CARRYING OUT THE INVENTION In order to explain the present invention in more detail, the present invention will be described below with reference to the accompanying drawings. First, six configuration examples of the first controllable switching means and the first current path means described above are shown one by one in each of the circuit diagrams (a) and (b) of FIGS.

In each of the circuits shown in FIGS. 8A and 8B, the thyristor 7 is used as the first controllable switching means, the diode 8 is used as the first non-controllable switching means, and the one-way controllable switch 9 is used. , 13 correspond to the aforementioned first unidirectional controllable switching means, and the diode 10 corresponds to the aforementioned second non-controllable switching means. The above-described first current path means corresponds to a current path connecting both ends of the diode 8 through the DC power supply 1 and the resistor 6.

When the one-way controllable switch 9 included in the circuit of FIG. 8A is used in, for example, a certain circuit (not shown), it operates as follows.

If the applied voltage of the unidirectional controllable switch 9 is zero or reverse and the thyristor 7 is on, the DC power supply 1
A current flows through the loop including the diode 10, the thyristor 7 and the resistor 6. However, in the case of the separately-excited commutation, the magnitude is set to be equal to or less than the holding current of the thyristor 7 so that this current does not prevent the thyristor 7 from being turned off.

On the other hand, if the voltage applied to the unidirectional controllable switch 9 is in the forward direction and the thyristor 7 is on, the forward voltage source (not shown; this is connected between the terminals 11 and 12), A current flows through the loop including the terminal 12, the thyristor 7, the resistor 6, the DC source 1 and the terminal 11.

Of course, the main current mainly flows through the thyristor 7 and the diode 8, so that both ends of the diode 8 are naturally clamped by the ON voltage. Therefore, in the case of the separately-excited commutation, the magnitude of the current flowing through the DC power supply 1 and the resistor 6 can be set to be equal to or smaller than the holding current of the thyristor 7 as described above.

In order to detect the ON / OFF state of the thyristor 7, the resistance 6
It is sufficient to detect whether or not the current is flowing. The specific method will be described later.

Further, the magnitude of the current of the resistor 6 may be smaller than the holding current value only when the thyristor 7 is about to turn off. That is, the current may be larger than the holding current value except at that time.

The above description can be similarly applied to the circuit in FIG.

The circuit of FIG. 9A is obtained by connecting the circuit of FIG. 8A in which the diode 14 is connected in series to the unidirectional controllable switch 9 in the same direction and the circuit of FIG. 2B in parallel. Such a circuit has the advantage that only one DC power supply 1 is required as compared with the prior art. Note that the circuit of FIG. 9A becomes an arm pair similarly to the circuit of FIG. 4 when the connection of the diodes 4 and 14 is disconnected. Similarly, the circuit of FIG. 9 (b) is also possible.

The circuit of FIG. 10A is a circuit in which a diode 15 is connected in anti-parallel to a unidirectional controllable switch in which a diode 4 and a thyristor 5 are connected in series in the circuit of FIG. 2B,
This is a circuit in which the circuits of FIG. 8 (a) are connected in series. This also has the advantage that only one DC power supply 1 is required as compared with the prior art. However, it may be necessary to insert a constant current means such as a constant current diode in series with the resistor 2 so as not to prevent the thyristor 5 from being turned off. Similarly, the tenth
The circuit of FIG. 2B is also possible.

8 (a) to 10 (b) show an example in which a thyristor is used as the above-mentioned first controllable switching means, but each of the first controllable switching means is a triac. , Bipolar transistor, power MOS / FE
Any controllable switching means such as T and static induction transistor may be used.

Next, embodiments of the present invention will be specifically described.
The embodiment shown in FIG. 1 uses a transistor 18 for the first controllable switching means described above. Since the open collector transistor 16 and the like detect the current of the resistor 17, the output of the transistor 16 turns on the transistor 18,
You can see off.

The embodiment shown in FIG. 11 corresponds to the on / off detection circuit described in the second or third claim. diode
Reference numeral 15 corresponds to the third non-controllable switching means described in each of the preceding paragraphs, and the diode 15 prevents the load current in the opposite direction from flowing through the diode 10.

Also, in order to detect the current of the resistor 24, two diodes 22, two resistors 23 and a photo coupler 20 @
A Toshiba TLP550 # or the like detects the collector current of the transistor 18, that is, the sum of the current of the resistor 24 and the main current of the diode 8.

The reason for this is that the main current does not hinder detection of whether the current of the resistor 24 is flowing.

That is, when the transistor 18 is off, both currents are always zero. On the other hand, when transistor 18 is on, the current in resistor 24 causes a substantially constant voltage drop across two diodes 22 whether or not its main current is flowing.

As a result, the on / off state of the transistor 18 can be determined from the output of the transistor 19 operating according to the sum of the voltages of the two diodes 22.

The threshold of the collector current of the transistor 18 at which the built-in light emitting diode 25 blinks is determined by the size of the resistors 21 and 23.

Thus, the diode 8 passes through the DC power source 1 and the resistor 24.
The detection of the current flowing in the current path connected in parallel to the current path is not limited to the current path.

In the embodiment shown in FIG. 12, the current detection of the resistor 24 is performed at two places. When transistor 18 is on, the current in resistor 24 flows through diode 10 or 15. So diode 1
Each transistor 1 that operates according to the presence or absence of each current of 0 and 15
The outputs of 9 and 27 are combined into one by a logical sum (OR) and input to the transistor 26. The on / off state of the transistor 18 can be determined from the output of the transistor 26.

The embodiment shown in FIG. 13 is based on the circuit of FIG. 10 (b), and uses transistors 18 and 29 instead of thyristors. This embodiment corresponds to the on / off detection circuit described in the ninth or tenth aspect of the present invention.

In this embodiment, it is detected whether both the transistors 18 and 29 are off. In addition, since the currents of the resistors 24 and 28 both flow through the two diodes 22 and the like, only one current detection unit is required.

The embodiment shown in FIG. 14 corresponds to the on / off detection circuit described in claim 7 and is for a multiphase AC circuit.
One switching circuit 30 is connected between the midpoint terminal 38 and each outer terminal 31. Switching circuit 30
Is based on the circuit of FIG. 9 (b), and uses transistors 18 and 29 instead of thyristors.

The first mechanism for detecting the on / off state of the transistor 18 is
It is the same as that of the circuit of the figure. The transistor 29 is also a transistor based on the conventional circuit of FIG.
It is 16 mag.

The diode 39 protects the transistor 16 from a reverse surge voltage applied between the base and the emitter of the transistor 16. The diode 40 is provided as a measure against the reverse voltage of the transistor 29.

Incidentally, as to connect the plurality of switching circuits 30, one between each of the outer terminals 31 and the midpoint terminal 38, the embodiment of Figure 13 can be connected one by one in the same manner between the terminals, the The circuit is an on / off detection circuit according to claim 11.

In the embodiment shown in FIG. 15 , four bridge-connected diodes 4, 8, 10, 15 and a transistor 18 are connected to a terminal 41,
An AC switch is formed between 42. The diode 3 may be omitted, but prevents unnecessary current from flowing from the diode 4 toward the transistor 16.

In the embodiment shown in FIG. 16, DC is obtained from an AC power supply 43 through a transformer 44, a rectifier 45, and a DC constant voltage circuit 46. Plus the DC power source, the negative connection is opposite to that of the circuit of Figure 15. The on / off state of the transistor 18 can be determined from the output of the transistor 47.

In the embodiment shown in FIG. 17 , the midpoint terminal 49 and each outer terminal 4
There is one AC switch between 8, 50. This embodiment is a circuit obtained by combining two circuits shown in FIG. 15 immediately before.

Each embodiment of FIGS. 15 to 17 corresponds to the on / off detection circuit described in claim 8.

FIG. 18 shows a circuit diagram of an embodiment and an arm pair using the same. The same reference numerals are connected to the connection terminals 54 to 57, respectively. This arm pair is a two-way arm pair that connects the midpoint terminal 52 and the outer terminals 51 and 53. This embodiment comprises transistors 18, 29, 47, 66 and diodes 3, 4, 8, 10, 15, etc. based on the circuit of FIG. 10 (a).
It corresponds to an on / off detection circuit described in claim 9.

Transistors 64 and 65 that are turned on and off in accordance with pulse signals input to input terminals 58 and 59 control transistors 60 and 61 via pulse transformers 62 and 63, respectively.

During the on period of transistor 18, transistor 47 prevents transistors 64, 60 from turning on. On the other hand, during the ON period of the transistor 29, the transistor 66 prevents the transistors 65 and 61 from turning on.

Therefore, even if the turn-off of the transistor 18 or 29 is delayed by each storage time or the like, the short-circuit between the outer terminals 51 and 53 does not occur because the transistors 18, 60 or 29 and 61 are not simultaneously turned on. .

Similarly, if control is performed to prevent the transistors 18 and 29 from being turned on in accordance with the on and off of the transistors 60 and 61, the prevention of the short circuit between the outer terminals 51 and 53 is complete.

FIG. 19 shows a circuit diagram of an embodiment and an AC-AC converter using the same. The same reference numerals are connected to the connection terminals 67 to 70, respectively.

This embodiment detects on / off of the thyristors 5 and 7 based on the circuit of FIG. 10 (b), and corresponds to an on / off detection circuit described in claim 10.

This AC-AC converter supplies an AC current to a load resistor 73 using a series resonance circuit of a reactor 75 and a commutation capacitor 74. In this AC-AC converter, the thyristors 71 and 72 are turned off by turning off both thyristors 5 and 7. Are triggered at the same time. The mechanism is as follows.

When the thyristor 5 or 7 is on, a current flows from the transistor 76 to the coil 78, and magnetic energy is stored in the coil 78. When the thyristors 5 and 7 are both turned off and turned off, the transistor 76 is turned off.
And flows through the resistor 77 and the like.

Since this current flows through the base of the transistor 80 during a period determined by the time constant of the coil 78 and the resistor 77, the transistors 81 and 82 are turned on during a period corresponding to this. As a result, the two thyristors 71, 72 are triggered via the pulse transformer 83.

This trigger period is set shorter than a half cycle of the series resonance circuit, and before the resonance current flows through one of the thyristors 71 and 72 during the half cycle and then reverses, the other recovers the off state. It is like. Therefore, this resonance current flows intermittently every half cycle.

FIG. 20 shows a circuit diagram of an embodiment for forming an arm pair and an accessory circuit thereof. This embodiment corresponds to the on / off detection circuit described in claim 4 and includes a midpoint terminal 85 and an outer terminal.
A one-way arm pair that connects 84 and 86 is configured. This arm pair has a short-circuit prevention function.

The components of the transistors 96 and 97 (power MOS FET) and the diodes 3, 4, 8, 10, and 14 are based on the circuit of FIG. 9B, but the outer terminals 84 and 86 are separated. .

A drive circuit centered on transistors 90-92 or 93-95 drives transistors 96 or 97. Each drive circuit operates according to the on / off signal input to each input terminal 87,88.

During the on period of transistor 96, transistor 89 prevents transistors 93, 94, 97 from turning on. on the other hand,
During the on-period of transistor 97, transistor 16 prevents transistors 90, 91, 96 from turning on.

During the ON period of the transistor 94, its emitter current flows toward the diode 14 or 10, and the gate-source voltage of the transistor 97 is kept constant by the Zener diode 98.

FIGS. 21 and 22 show one embodiment and a left half and a right half of a circuit diagram of a circuit of an ignition device using the same. This ignition device comprises a primary coil 121a of an ignition coil 121 and a commutation capacitor 1
24 is a series inverter type ignition device using a series resonance circuit formed by 24. In the figure, 99 is a DC power supply, 100 is a DC-DC converter that outputs a negative voltage, and 103 is a three-terminal regulator.

First, the main circuit of this series inverter will be described. This main circuit is composed of thyristors 113 and 119 and a primary coil 121.
The DC power supply is composed of a DC-DC converter 100 and a current capacitor 101.

Resistors 116 and 117 (1 ohm each) should be thyristor
113 and 119 are protection resistors when the power supply capacitor 101 is short-circuited.

Diodes 122 and 123 limit the voltage on commutation capacitor 124 from zero to the voltage on power supply capacitor 101.

Since spark occurs at the time of charging and discharging of the commutation capacitor 124, if the charging and discharging are repeated, the generation will be continuous.

The operation of the main circuit is as follows. Thyristor 113
Immediately after the power supply is turned on, since the voltage of the commutation capacitor 124 is zero, the voltage of the power supply capacitor 101 is
a, and a high voltage is induced on its secondary side. As a result, a spark is generated in the ignition discharge gap 125.

Thereafter, when the commutation capacitor 124 is charged to the voltage of the power supply capacitor 101, the diode 122, which was off because of the reverse voltage, turns on. Therefore, since the thyristor 113 and the diode 122 operate as a flywheel diode for the primary coil 121a, the voltage of the commutation capacitor 124 does not increase any more.

On the other hand, immediately after the thyristor 119 is turned on, only the voltage of the commutation capacitor 124 charged to the voltage of the power supply capacitor 101 is applied to the primary coil 121a in a direction opposite to the previous direction, and the secondary side thereof has an opposite direction. A high voltage in the direction is induced. As a result, a spark is generated in the ignition discharge gap 125.

After that, when the voltage of the commutation capacitor 124 becomes zero,
The diode 123, which was off because of the reverse voltage, turns on. For this reason, the thyristor 119 and the diode 123 are used for the primary coil 121a as a flywheel /
Acting like a diode, the voltage across commutation capacitor 124 remains zero.

Thereafter, the same operation is repeated according to the turn-on of the thyristors 113 and 119.

While the sparks are generated, these sparks short-circuit both ends of the secondary coil 121b, so that the inductance of the ignition coil 121 viewed from the primary side is
It becomes smaller than the inductance of a. The former inductance is the leakage of the primary coil 121a and the secondary coil 121b.
It is determined by the inductance and the like.

Also, the current flowing through these leakage inductances contributes to these sparks,
Does not contribute to these. Rather, the latter current is merely a factor that unnecessarily delays the turn-off of the thyristor 113 or 119, so that it is better to be as small as possible.

For that purpose, the ignition coil 121 is designed so that its exciting inductance is as large as possible compared to these leakage inductances.

Now, the trigger circuit of the ignition device will be described. In this ignition device, similarly to the AC-AC converter shown in FIG. 19 , the turning off of the thyristor 113 triggers the turning on of the thyristor 119, while the turning off of the thyristor 119 triggers the turning on of the thyristor 113. Becomes Accordingly, the turn-on timing of each of the thyristors 113 and 119 is automatically optimized, and the ignition device becomes an oscillator as a whole.

Therefore, the transistor 107 and the like detect the on / off of the thyristor 119, and the transistor 115 and the like detect the thyristor 113.
ON and OFF are detected. The on / off detection circuit of the thyristor 119 is based on the circuit of FIG.
5 and the diodes 106 and 118 are provided to prevent surges such as ignition noise. The on / off detection circuit of the thyristor 113 is based on the circuit of FIG.
The series circuits 4 and 101 (which are hard to see in the figure, but one end of which is grounded) correspond to the DC power supply 1 in FIG. 2 (a). Since the voltage of the power supply capacitor 101 is several hundred volts, the value of the resistor 114 is around 100 kilo ohms.

How to use pulse transformers 112 and 120 is different from normal,
This is a method of actively using the saturation of each magnetic flux.

In the pulse transformer 112, the period from the time when the transistor 109 is turned on to the time when its magnetic flux is saturated
The back electromotive force generated on the next side is applied between the gate and cathode of the thyristor 113. Therefore, when the magnetic flux is saturated, the trigger operation automatically ends.

Then, when the transistor 109 is turned off, the magnetic energy stored in the pulse transformer 112 is consumed by the Zener diode 110 and the resistor 111, and the next trigger operation is prepared.

Conversely, in pulse transformer 120, transistor 115
During the ON period of the magnetic energy is stored inside,
When transistor 115 turns off, its magnetic energy is released as a trigger current for thyristor 119. Therefore, this triggering operation automatically ends when the magnetic energy is lost.

The whole trigger operation is as follows. Thyristor 11
When the transistor 107 is turned off together with 9 and the ignition signal input to the input terminal 108 falls, the transistor 109 is turned off.
Turns on, and the thyristor 113 is triggered.

Magnetic energy stored in the pulse transformer 120 during the ON period of the thyristor 113 and the transistor 115 is applied to the gate of the thyristor 119 when they are turned off.

When transistor 107 turns on with thyristor 119, transistor 107 turns transistor 109 off if the ignition signal is still low.

During the on-period of thyristor 119 and transistor 107, pulse transformer 112 emits its magnetic energy to prepare for the next triggering operation.

When transistor 107 turns off with thyristor 119, if the ignition signal is still low, transistor 109 turns on and thyristor 113
Is triggered.

Thereafter, the same is repeated in the same manner. This repetition continues as long as the ignition signal is at a low level.

However, at the time of the turn-off, if the ignition signal is at a high level, the transistor 109 remains off,
This ignition device stops the generation of spark.

If you pay attention to the winding method of each winding,
Since 112 and 120 can be wound on a common core, one pulse transformer core can be saved in this case, and the space can be reduced accordingly.

Then, the ignition coil 121 and the ignition discharge gap 125 are shielded to prevent ignition noise. The same applies to the next ignition device.

23 and 24 show a left half and a right half of a circuit diagram of an embodiment and an ignition device circuit using the same, respectively. This igniter is also a series inverter type igniter, and its main circuit configuration is the same as that of the igniters of FIGS. 21 and 22.

In the figure, reference numeral 126 denotes a DC-DC converter that outputs a negative voltage. The Darlington-connected transistors 139 to 141 constitute a PNP transistor equivalently.

In this igniter, the turn-off of the transistors 142 to 144 is the same as that of the igniter of FIGS.
141141 is turned on, while the turn off of transistors 139-141 triggers the turn on of transistors 142-144.

Therefore, the transistor 107 and the like
The on / off state of 141 is detected, and the transistor 134 and the like detect on / off states of the transistors 142 to 144. Transistor
On-off detection circuit 139-141 is based on a circuit diagram the 8 (b).

A monostable multivibrator centered on transistors 129-131 controls transistors 142-144. In this monostable multivibrator, the capacitor 123 is charged by the transistor 130 whose collector is grounded in order to improve the collector voltage waveform of the transistor 129.

On the other hand, a pulse circuit centering on the transistors 134 to 135 is connected to the transistors 139 to 139 via the transistors 136 to 138.
Control 41. During the on-periods of transistors 142-144, transistor 134 charges capacitor 133, and when they turn off, capacitor 133 discharges. Since the transistor 135 is turned off for a period corresponding to this discharge,
The transistors 136 to 141 are turned on.

The oscillating operation of the entire ignition device is similar to that of the ignition device of FIGS. 21 and 22. When the ignition signal input to the input terminal 127 falls, or when the transistors 139 to 141 and 107 are turned off while the ignition signal is at a low level, the transistor 128 activates the monostable multivibrator. Trigger. Thereafter, for a predetermined period, the monostable multivibrator
Keep ~ 144 on. Then, after the transistors 142 to 144 are turned off, the pulse circuit including the transistor 134 keeps the transistors 136 to 141 on for a predetermined period.

Each of the ignition devices shown in FIGS. 21, 22, 23, and 24 is a high-voltage generator that generates positive and negative high voltages without the ignition discharge gap 125. If a discharge lamp is connected instead of the discharge gap 125, a discharge lamp lighting device is obtained. If an ozone generation discharge gap is connected in place of the ignition discharge gap 125, they become an ozonizer, and if an induction heating coil is connected instead of the ignition coil 121, they become an induction heating device.

FIGS. 25 and 26 show two embodiments and AC-
The left half and the right half of the circuit diagram of the AC converter are shown. This AC
The AC converter supplies an AC current to the load resistor 73 using a series resonance circuit of the commutation capacitor 74 and the reactor 75.

The main circuit is composed of thyristors 5, 7, 71, 72, a commutation capacitor 74, a reactor 75, a load resistor 73, and the like. The on / off detection circuit is based on the circuits of FIGS. 9 (a) and 9 (b).

The same numbers are connected to the connection terminals 145 to 152, respectively. The thyristors 5, 71 or the thyristors 7, 72 are triggered simultaneously, and the two sets mutually turn off their own set to trigger the turn off of the other set.

For this purpose, the transistor 66 and the like detect the ON / OFF state of the thyristor 5 and transmit the output to the transistor 153 via the photo coupler 20 on the left side in the figure. The transistor 153 and the like detect whether or not both the thyristors 5 and 71 are off.

On the other hand, the transistor 47 and the like detect on / off of the thyristor 7 and transmit the output to the transistor 159 via the photocoupler 20 on the right side in the figure. Transistors 159 and the like detect whether both thyristors 7 and 72 are off.

How to use pulse transformers 112 and 157 is different from normal,
It is the same as that of the ignition device of FIG. 21 and FIG. However, in the case of the pulse transformer 112, not only the secondary
The back electromotive force on the secondary side is also used. In the case of the pulse transformer 157, the stored magnetic energy is
Emitted from the two output windings.

The overall trigger operation is similar to that of the ignition device of FIGS. 21 and 22. When the start / stop signal input to the input terminal 154 falls, or when the transistor 153 turns off together with the thyristor 5 or 71 while this signal is at the low level, the transistors 155 and 156
Triggers the thyristors 7, 72 via the pulse transformer 112.

On the other hand, the magnetic energy stored in the pulse transformer 157 during the ON period of the thyristor 7 or 72 is released as a trigger current of the thyristors 5 and 71 when they are turned off. As a result, the triggers of the thyristors 5, 71 and the thyristors 7, 72 are alternately repeated. To stop the trigger operation, the start / stop signal may be set to a high level.

Even if the thyristors 5 and 71 are turned on at the same time, the main current flows through only one of them depending on the voltage polarity of the AC power supply 43 at that time. This is the same for the thyristors 7 and 72.

Lastly, as a supplement, each embodiment uses a Fast Recovery type for each diode.

In the embodiment of FIG. 15 , the diodes 3, 4,
The current path between the connection point 8 and the collector of the transistor 18 flows only in one direction. Therefore, although it is meaningless, even if another diode is inserted into this current path so as not to obstruct the current flow, the operation of this embodiment is not impaired. In this case, the diode does not play its original role, but rather just as a current path, like a wire.

Further, even if the cathode of the diode 3 is disconnected from the connection point while the other diode is inserted and the cathode is directly connected to the collector of the transistor 18, the operation of this embodiment is not impaired. This is because the additional diode serves only as a current path.

These facts can be similarly applied to the embodiments shown in FIGS. 16 and 17. In the circuit of FIG. 8 (a), even when inserting align them with the direction of another diode between the diode 8 and the thyristor 7, the same is true.

Then, in each of the circuits shown in FIGS. 8 (a) to 10 (b), the portion of the diode 8 is non-controllable (one-way).
It is not limited to the switching means, but may be any one-way thyristor, one-way controllable switching means, or any other unidirectional switching means in which no reverse current flows. This is the same in other embodiments.

In this case, the present invention corresponds to the on / off detection circuit described in claim 12 or 13.

However, both the unidirectional thyristor and the unidirectional controllable switching means are limited to those in which a reverse current does not flow even if a reverse voltage is applied between both main terminals when the ON control is performed. Moreover, when the thyristor 7 (the first controllable switching means described above) is turned on, it must be turned on. As the driving means for the ON control, for example, there is a pulse transformer 112 or 157 of the circuit shown in FIGS. 25 and 26.

(Related patent: PCT / JP87 / 00053) Industrial applicability As described above, the on / off detection circuit according to the present invention is useful as a means for detecting on / off of all kinds of controllable switching means. This is particularly suitable for detecting on / off of the controllable switching means included in the arm of the power conversion circuit.

Of course, the present invention can be applied to a device using this power conversion circuit, for example, an ignition device including an ignition device for an internal combustion period, a high voltage generator, an ozonizer, a discharge lamp lighting device, an induction heating device, and the like.

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Claims (13)

(57) [Claims] 1. A second non-controllable switching means is connected in anti-parallel to a first one-way controllable switching means in which the first controllable switching means and the first non-controllable switching means are controlled in series. And connected in parallel to the first non-controllable switching means;
First current path means for flowing a first current through the first controllable switching means in the same direction as the forward direction of the first unidirectional control switching means when the first controllable switching means is on; An on / off detection circuit, comprising: a first current detection unit configured to detect the first current. 2. A second unidirectional controllable switching means comprising a third non-controllable switching means connected in series to said first unidirectional controllable switching means. 2. The on / off detection circuit according to claim 1. 3. The on / off detection circuit according to claim 2, wherein said third non-controllable switching means is connected to said first controllable switching means. 4. A third one-way controllable switching means in which a second controllable switching means and a fourth non-controllable switching means are connected in series, and the second one-way controllable switching means is connected to both of them. The forward direction is set to the same direction, and the second controllable switching means and the first non-controllable switching means are adjacently connected in series, and the second controllable switching means is turned on. When the second current flows through the second controllable switching means in the same direction as the forward direction of the third unidirectional controllable switching means without passing through the fourth non-controllable switching means, The on / off detection circuit according to claim 3, further comprising: a current path unit; and a second current detection unit that detects the second current. 5. The on / off detection circuit according to claim 4, wherein said second and third unidirectional controllable switching means are connected in anti-parallel. 6. The on / off detection circuit according to claim 4, wherein said first and second current detection means are common. 7. A plurality of on / off detection circuits according to claim 5, all of which are connected to each of said first non-controllable switching means and each of said second controllable switching means. An on / off detection circuit, which is connected between points. 8. The on / off switch according to claim 1, wherein said first and second non-controllable switching means are bridge-connected to fifth and sixth non-controllable switching means. Detection circuit. 9. A fourth one-way controllable switching means in which third controllable switching means and a seventh non-controllable switching means are connected in series and said first one-way controllable switching means are reversed from each other. Direction, and the first,
The third controllable switching means are connected in series next to each other, and an eighth non-controllable switching means is connected in anti-parallel to the fourth unidirectional controllable switching means. The controllable switching means connects a connection point of the seventh non-controllable switching means to a connection point of the first and second non-controllable switching means, and the third controllable switching means is turned on when the third controllable switching means is on. A third current path means for causing a third current to flow through the third controllable switching means in the same direction as the forward direction of the fourth unidirectional controllable switching means; and a third current detecting means for detecting the third current. The on / off detection circuit according to claim 1, further comprising a current detection means. 10. The on / off detection circuit according to claim 9, wherein said first and third current detection means are common. 11. An on / off detection circuit according to claim 9, wherein all of said on / off detection circuits are provided for each of said first non-controllable switching means and each of said second non-controllable switching means. An on / off detection circuit, which is connected between connection points. 12. A fifth unidirectional controllable control in which a reverse current does not flow even when a reverse voltage is applied between both main terminals of the first non-controllable switching means when the first non-controllable switching means is on-controlled. A driving means for turning on said fifth one-way controllable switching means when said first controllable switching means is on-controlled by switching means is provided. An on / off detection circuit according to any one of items 6, 8 to 10. 13. A fifth unidirectional switching device in which each of said first non-controllable switching means is turned on so that no reverse current flows even if a reverse voltage is applied between its main terminals. The control switching means replaces one by one,
8. A driving means for turning on each of said fifth one-way controllable switching means which is paired with each of said controllable switching means when said controllable switching means is turned on. Or an on / off detection circuit according to claim 11.