JPS59163724A - Conducting and interrupting device near zero potential of accurrent - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for controlling conduction and interruption of alternating current without sparking.

When an AC power source is connected to an electrical appliance as a load via a switch, the current instantaneously flowing into the load changes greatly depending on the timing of opening and closing of the switch. That is, if the switch is turned on at the instant of a high potential value of an AC wave, a current ten times the normal current will flow to the load. On the other hand, if the switch is turned on during the zero potential of alternating current, it is connected to the load in a no-current state.

However, it is difficult to artificially select the moment at which the switch is turned on.

Therefore, the present invention provides a device that no matter what timing the switch is operated, the switch is always turned on at the moment of rising from the zero potential of the alternating current, and when the switch is turned off, the device is always cut off near the zero potential of the alternating current. This is what we provide.

That is, in the present invention, the control rectifying element is not in a conductive state at the moment when the alternating current voltage rises from zero potential, and is always in a non-conductive state when the alternating current voltage reaches zero potential from the fall of the alternating current voltage when cutting off the electric circuit. The purpose is to reduce transient shocks of current.

Next, the present invention will be explained according to illustrated embodiments.

As shown in FIG. 1, one end of an AC power supply AC that generates a controlled alternating current is connected to an anode A of a controlled rectifying element such as a silicon controlled rectifying element SCB via a switch S, and is also connected to an anode A of a controlled rectifying element such as a silicon controlled rectifying element SCB. It is connected to the primary winding P of a transformer H for generating . The secondary winding Q of the transformer H is connected to the gate G of the silicon-controlled rectifier SCR via a half-wave rectifier circuit consisting of a diode D and an integrating circuit consisting of a resistor R1 and a capacitor C. Note that the reference numeral 2 indicates the cathode of the silicon-controlled rectifying element SCR, and the reference numeral 2 indicates a load such as a lamp.

In such a state, if we consider the case where there is no diode D1, resistor R1, and capacitor C on the secondary side of the transformer, the voltage applied to the anode A of the silicon-controlled rectifying element SCR and the voltage applied to the gate G. The voltage shown in Figure 2 (a)
, (b), when the phase is 1800
As a result, the silicon controlled rectifying element 8CR does not become conductive.

However, as shown in FIG.
1 When a capacitor C is connected to the secondary side of a transformer H, the current appearing in the secondary winding Q charges the capacitor C via a resistor R after being half-wave rectified by a diode D. The voltage appearing across the capacitor C at that time is as shown in Figure 2 (q).
, to L.

MlNlo, P both indicate the phase position of the AC signal,
The symbol TO indicates the gate trigger voltage of the silicon controlled rectifier SCR. Further, symbols VM, V1+, and ■0 indicate voltage changes of capacitor C' when switch S in FIG. 1 is turned on at phase positions M1N and 0, respectively, and at other phase positions J1, L, When the switch S is turned on at P, it becomes the same as VM.

Here, if the integration time constant is appropriately determined depending on the size of the resistor R1 and the capacitor C, the voltages VM and VN will relatively quickly exceed the gate trigger voltage TO and make the silicon-controlled rectifier SCR conductive. At the same time as the voltage applied to the anode A of the silicon-controlled rectifier SCR rises to the positive side, the silicon-controlled rectifier SCR conducts and the load 2
A current flows through. In addition, the voltage 0 exceeds the gate trigger voltage TG after waiting for the next half cycle, and at the same time the voltage applied to the anode A of the silicon-controlled rectifier SCR rises to the positive side, the silicon-controlled rectifier SCR becomes conductive. do.

In this way, no matter what phase position of the AC signal the switch S in FIG. The power supply and load are connected at the moment of rise from .

Note that the discharge time constant of the capacitor C is determined by the capacitance of the capacitor C and the internal resistance at the gate G of the silicon-controlled rectifier SCR.

FIG. 3 shows another embodiment, in which silicon-controlled rectifier S
This is an example using a double-wave rectifier circuit in which a CR and a diode D are connected in a bridge connection, and the current of the AC power supply always flows through the load 2 from the vicinity of the rise of the AC voltage from zero potential.

Fig. 4 shows an example in which the alternating current is passed directly to the load Z, and the current is passed from the silicon-controlled rectifier SCR1 to the return line from the diode D4 through the load Z, and in the next half cycle, the current is passed through the silicon-controlled rectifier SCR1 to the return wire. The diode D3 is energized from the SCR2 through the load Z, and the entire cycle of alternating current is supplied to the load B.

The waveform is shown in FIG. That is, waveform (1) is the current that flows from silicon-controlled rectifier SCR+ through load Z to the return path via nine diodes D4, and waveform (2) is the current that flows from silicon-controlled rectifier 5CR2 through load 2 and diode D3. This is the current that flowed through it. FIG. 6 shows an embodiment using a bidirectional conduction thyristor SCR,
There are some that supply the trigger voltage to have the lowest potential trigger mode.

In the above embodiments, a diode is used as the half-wave rectifying element, but it is needless to say that it is not limited to a diode as long as it has a half-wave rectifying effect. Furthermore, the integration circuit is not limited to the combination of resistors and capacitors, and various modifications are possible.

Furthermore, it goes without saying that the controlled rectifying element may be any element other than the silicon controlled rectifying element, as long as the conduction in a specific direction is controlled by a control signal of a certain level or higher.

The above is the case when the switch is turned on, but the following is the case when the switch is turned off.

When interrupting an alternating current circuit, if the moment of interruption is near the peak value of the alternating current, a large current will be interrupted, and damage to peripheral equipment may occur due to spark discharge or the like.

FIG. 7 is an explanatory diagram of a circuit for interrupting AC near zero potential. Now, the switch S] is closed, and a half-wave rectified half-wave rectified voltage of opposite phase to the anode is applied to the integration circuit having a time constant determined by the capacitance C and the internal resistance of the gate of the SCR, as shown in the waveform shown in Figure 8C. SCR is conductive. To interrupt the current,
By opening the gate control voltage supply switch S+, the accumulated voltage of the integrating circuit is reduced as shown in FIG. 8C. When the gate voltage becomes lower than the trigger voltage TG, the SCR stops energizing after only half a cycle, and becomes non-conducting from the next rising edge. Therefore, the SCR current has a waveform as shown in the shaded area in Figure 8E. The current is cut off near zero potential.

The waveforms in FIG. 8A are the AC voltage of S'CR anode A, B
The waveform C is the reverse phase voltage for gate driving, and C is the rectified voltage waveform of the integrating circuit.

Figure 9 shows the control rectifier 8CR/1 and SCR on the current main line.
, 2 are connected in opposite directions to supply full-wave alternating current.

When the switch S1 is closed and then S is closed, current is supplied to the gate power transformer H, and the current is supplied to the gate power transformer H through the diode D1.
It is charged to 1 and 5CRI becomes conductive. At the next instant, capacitor C2 is charged by diode D2, and S CR
2 also becomes conductive, and all alternating current flows as shown in the waveform of FIG.

When the current is cut off, when the switch S1 of the power transformer H for gate control is opened, the thyristor becomes non-conductive because the voltage becomes lower than the non-trigger voltage of the gate due to the charge discharge of the capacitors C1 and C2.

That is, energization ends at the falling zero point of the alternating current, and the current is cut off. The current is cut off at point F of the waveform in FIG.

Figure 11 shows an example of a three-phase motor that uses SCR control elements for each of the three main lines.The main circuit remains closed and the three-phase motor can be operated by simply opening and closing the power supply for the control gate. The stop is performed from the rising point of the current.

As described above, according to the conduction and disconnection device of the present invention,
This makes it possible to supply a current of several amperes to a maximum of amperes to the load by turning on the switch immediately after the start-up of the alternating current. Further, when cutting off the current, by cutting off the control gate power supply, the main current is cut off near zero potential at the fall of the current, and no sparks are generated. Therefore, according to the present invention, there is no need for a conventionally used large-capacity power receiving device, the device is simple, there is no need to gradually increase the voltage when switching on, and the operation is simple. Moreover, since there is no fear that an excessive current will flow through the product, it has the practical benefit of extending the life of the product.

For this reason, the conduction and disconnection device of the present invention can be used in various devices such as power plants, substations, factories that require large amounts of current, computer equipment, etc., as well as various stadiums, parks, and amusement parks. Used in large lighting equipment that requires large currents such as in the ground, as well as various electrical equipment such as refrigerators, air conditioning equipment, air conditioners, etc., where switches operate automatically and current is constantly supplied intermittently. If you do, it will be extremely effective.

[Brief explanation of the drawing]

The figures show an embodiment of the present invention, in which Figure 1 is a basic circuit diagram, Figure 2 (a) is a diagram showing the relationship between AC waveform and switch-on time, and Figure 2 (b) is a diagram of a transformer. The waveform diagram appearing in the secondary winding, Figure 2 (C) is the voltage waveform diagram of the capacitor, and Figure 3
The figure shows a circuit diagram when a controlled rectifier is assembled into a bridge, Figure 4 is a circuit diagram when alternating current is directly supplied to a load, Figure 5 is an output waveform diagram when the circuit diagram in Figure 4 is used, and Figure 6 is a circuit diagram when a control rectifier is assembled into a bridge. The figure is a circuit diagram when a bidirectional conduction thyristor is used. FIG. 7 is an explanatory diagram of the shutoff, and FIG. 8 shows the waveform at the time of shutoff. FIG. 9 shows a switch circuit for full-wave AC current flow, FIG. 10 shows its output waveform, and FIG. 11 shows a switch circuit used in a three-phase motor. The symbols in the figure are explained as follows. AC is an alternating current power source S is a switch SCR is a controlled rectifier element H is a transformer P is a transformer-secondary winding Q is a diode in the secondary winding of the transformer R is a resistor C is a capacitor 2 is a load Patent applicant 3rgI Temple 4 @ Δ Sai 5 Zume ItJ! g Procedural amendment dated August 18, 1980 Mr. Kazuo Wakasugi, Commissioner of the Japan Patent Office 1 Indication of the case Patent Application No. 38808 of 1988 2 Name of the invention Conduction/interruption device for alternating current near zero potential 3 Person making the amendment Relationship to the case Patent applicant 4, Application subject to amendment and full text of specification 5 Contents of amendment Procedural amendment 1 Indication of case Patent Application No. 38808 filed in 1982 2 Name of the invention Continuity/interruption device 3 Person making the correction 4, drawing to be corrected 5 Contents of the correction

Claims (1)

[Claims] A voltage of the opposite phase to the anode voltage of the control rectifier provided in the current circuit is supplied to the control electrode via a half-wave rectifier circuit and an integrating circuit,
After a certain period of time in the closed circuit, the voltage for the control electrode reaches the trigger voltage and becomes conductive from the next rising voltage, and when the control rectifier is in the conductive state, the power supply to the half-wave rectifier circuit and the integrating circuit is cut off. A conduction/cutoff device for alternating current near zero potential, which becomes non-conductive when the control voltage becomes below the non-trigger potential after a certain period of time and reaches the zero point of the fall of the anode voltage of the control rectifier. ′