CN202077009U - Isolating trigger circuit for thyristor - Google Patents

Abstract

The utility model provides an isolated trigger circuit for thyristor, which includes diode D51, resistors R51, R52, R53, voltage regulator, capacitor C51, transistor coupler U51, and bidirectional thyristor TR51; bidirectional thyristor TR51 The T2 pole of the diode is connected to one end of the AC power supply and the anode of the diode D51 through the load at the same time, and its T1 pole is connected to the other end of the AC power supply; the cathode of the diode D51 is connected to the collector of the triode of the transistor coupler through the resistor R53; the diode of the transistor coupler The anode of the DC power supply is connected to the output terminal of the DC power supply, and its cathode is connected to the control signal output terminal through the resistor R52. The emitter of the triode of the transistor coupler is connected to the G pole of the bidirectional thyristor TR51 through the resistor R51; the voltage regulator is connected in parallel with the capacitor C51 Between the collector of the triode of the transistor coupler and the T1 pole of the triac. The thyristor isolation trigger circuit provided by the utility model has the advantages of simple structure and low cost.

Description

A thyristor isolation trigger circuit

technical field

The utility model relates to a circuit structure, in particular to an isolation trigger circuit of a thyristor.

Background technique

At present, a large number of circuits need to be isolated by silicon controlled rectifiers, especially household appliances, such as inverter washing machines, inverter air conditioners, etc.

In the prior art, there are mainly two methods for isolation triggering of thyristors: the first is to use light-controlled bidirectional thyristors, as shown in Figure 1, this control method uses the control signal TR2 of the MCU, when TR2 is high level, the triode Q21 is turned on, the bidirectional thyristor IC21 is turned on, and thus the thyristor TR21 is turned on. Since the output terminal of bidirectional thyristor IC21 needs to be high-voltage resistant, its price is relatively high; the second type uses transformer isolation, as shown in Figure 2, which provides a group of power sources independent of the power supply of the control circuit. There is only a single-point connection with the AC input, which is relatively independent. The circuit has at least two outputs, and the output terminals are completely isolated. Its control loop is from AC220L-T1-G-R31-U31-Gnd1-, since the voltage of the trigger circuit is low voltage, it can use a low-cost ordinary photocoupler with only tens of volts withstand voltage, but This control method requires an additional set of loops, and increases the peripheral circuit of the transformer and the transformer, making the circuit structure more complex and increasing the circuit cost. It is far away from the power terminal (silicon controlled rectifier), which is inconvenient for wiring, which will increase the size and cost of the PCB. Therefore, the circuit structure for isolating and triggering the thyristor in the prior art is relatively complicated and the cost is relatively high.

It can be understood that the statements in this section only provide background information related to the present invention, and may or may not constitute so-called prior art.

Contents of the invention

The technical problem to be solved by the utility model is to provide a thyristor isolation trigger circuit with a simple structure and low cost in view of the defect that the circuit structure of the isolation trigger of the thyristor is relatively complicated and the cost is high in the prior art.

The technical solution adopted by the utility model to solve the technical problem is to provide a thyristor isolation trigger circuit, which is characterized in that it includes a diode D51, resistors R51, R52, R53, a voltage regulator, a capacitor C51, and a transistor coupler U51 , and bidirectional thyristor TR51; the T2 pole of the bidirectional thyristor TR51 is connected to one end of the AC power supply and the anode of the diode D51 through the load at the same time, and its T1 pole is connected to the other end of the AC power supply; the cathode of the diode D51 is connected to the transistor through the resistor R53 The collector of the triode of the coupler; the anode of the diode of the transistor coupler is connected to the output terminal of the DC power supply, and its cathode is connected to the output terminal of the control signal through the resistor R52, and the emitter of the triode of the transistor coupler is connected to the triac TR51 through the resistor R51 The G pole of the voltage regulator is connected in parallel with the capacitor C51 and then connected between the collector of the triode of the transistor coupler and the T1 pole of the bidirectional thyristor.

In the isolated trigger circuit of the thyristor provided by the utility model, the bidirectional thyristor can also be replaced by the unidirectional thyristor, and the circuit connection method of the anode of the unidirectional thyristor is the same as that of the T2 pole of the bidirectional thyristor. The circuit connection to the cathode of the thyristor is the same as the T1 pole of the triac.

In the above-mentioned isolated trigger circuit for silicon controlled rectifiers, the voltage stabilizing element is a resistor or a voltage stabilizing tube.

In the above isolation trigger circuit for silicon controlled rectifiers, the capacitor C51 is a polar capacitor.

The thyristor isolation trigger circuit provided by the utility model can isolate the thyristor by using an ordinary optocoupler, and only use one diode, three resistors, one voltage regulator and one capacitor to trigger the optocoupler, so The circuit provided by the utility model can realize the isolation and triggering of the thyristor, and at the same time, the components and parts are few and simple, so that the whole circuit is simple and the cost is low. the

Description of drawings

Fig. 1 is the circuit diagram of the isolated triggering of thyristor in the prior art;

FIG. 2 is a circuit diagram of another isolation trigger of a thyristor in the prior art;

Fig. 3 is a circuit diagram of a preferred embodiment of the isolated trigger circuit of the thyristor provided by the utility model. the

Detailed ways

In order to make the technical problems, technical solutions and beneficial effects solved by the utility model clearer, the utility model will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model, and are not intended to limit the utility model.

The thyristor isolation trigger circuit provided by the utility model mainly utilizes a transistor coupler (that is, an ordinary optocoupler well known to those skilled in the art) and simple and cheap electronic components to realize isolation triggering of the thyristor. The thyristor isolation trigger circuit provided by the utility model includes a diode D51, resistors R51, R52, R53, a voltage regulator, a capacitor C51, a transistor coupler U51, and a triac TR51; the T2 pole of the triac TR51 The load is connected to one end of the AC power supply and the anode of the diode D51 at the same time, and its T1 pole is connected to the other end of the AC power supply; the cathode of the diode D51 is connected to the collector of the triode of the transistor coupler through the resistor R53; the anode of the diode of the transistor coupler is connected to The output terminal of the DC power supply, its cathode is connected to the control signal output terminal through the resistor R52, the emitter of the triode of the transistor coupler is connected to the G pole of the triac TR51 through the resistor R51; the voltage regulator is connected in parallel with the capacitor C51 and then connected to the transistor coupling Between the collector of the triode of the device and the T1 pole of the bidirectional thyristor.

Preferably, the voltage stabilizing element is a resistor or a voltage stabilizing tube, referring to Fig. 3, which is a circuit diagram of a preferred embodiment of the isolated trigger circuit of the bidirectional thyristor provided by the utility model, wherein the voltage stabilizing element adopts a resistor R54, and divides the voltage The main function of resistor R54 is to clamp the voltage.

The thyristor isolation trigger circuit provided by the utility model can also be used for one-way thyristor, including diode D51, resistors R51, R52, R53, voltage regulator, capacitor C51, transistor coupler U51, and one-way thyristor TR51; the anode of the one-way thyristor TR51 is connected to one end of the AC power supply and the anode of the diode D51 through the load at the same time, and its cathode is connected to the other end of the AC power supply; the cathode of the diode D51 is connected to the collector of the triode of the transistor coupler through the resistor R53 ; The anode of the diode of the transistor coupler is connected to the output terminal of the DC power supply, and its cathode is connected to the output terminal of the control signal through the resistor R52. After being connected in parallel with the capacitor C51, it is connected between the collector of the triode of the transistor coupler and the cathode of the one-way thyristor. Since the one-way thyristor is rarely used for isolation in alternating current, and its circuit connection method is the same as that of the above-mentioned bidirectional thyristor, its circuit diagram is omitted here.

Referring to Fig. 3 again, the working principle of the isolation trigger circuit provided by the utility model is described as follows in conjunction with the circuit structure of the triac as the thyristor: the diode D51 rectifies the alternating current of the commercial power into direct current, and the resistors R53 and R54 divide the voltage , divide and press a lower stable voltage at the connection point of the resistors R53 and R54 to trigger the transistor coupler U51, and then the transistor coupler U51 drives the thyristor to conduct and isolates the thyristor at the same time. Among them, the power supply for the thyristor can be taken nearby, and it can be directly provided by the transistor coupler after rectifying and dividing the voltage by the diode, as shown in the power M terminal in the figure. When the power supply is in the positive half cycle of alternating current, the current flows from AC220_L through D51, R53 and R54, and then to AC220_N, and C51 stores energy for the power supply. When the AC power supply is in the negative half cycle, the capacitor C51 starts to discharge, and the possible path of the current is R52-R53-D51. Since D51 is reverse-biased, the negative half-cycle current cannot pass. Therefore, when the optocoupler is turned on, the trigger circuit will work, and the thyristor trigger conduction circuit is the positive pole of C51-U51-R51-G-T1-negative pole of C51. This circuit utilizes the voltage division of R53 and R54, and the high voltage is divided to R53, so ordinary optocouplers with low withstand voltage can be used. When the optocoupler is disconnected, due to the voltage division effect of R54, no high voltage will be generated at both ends of the optocoupler output, ensuring that the optocoupler U51 will not be broken down.

Among them, the diode D51 is a high-voltage-resistant diode, such as a cheap D51 (1N4007 can be used) with a voltage resistance of 1000V, which is enough to ensure that it will not be broken down during the negative half cycle, so that the circuit can work reliably. Therefore, the isolation trigger circuit of the thyristor provided by the utility model has few electronic components, and all of them are low-cost components, which makes the whole circuit structure simple and low in cost. Preferably, the capacitor C51 is a polar capacitor, its positive pole is connected to the collector of the triode of the transistor coupler, and its negative pole is connected to the cathode of the one-way thyristor, so as to better maintain the stability and reliability of the circuit operation and reduce the cost ( When the thyristor is a one-way thyristor, the connection principle of capacitor C51 is the same).

Those skilled in the art know that other voltage stabilizing circuits can be used to replace the above voltage stabilizing parts to stabilize the POWER_M point to a certain voltage range. This is a common technical means in the field, and all of them are included in the protection scope of the present invention.

The thyristor isolation trigger circuit provided by the utility model can be widely applied to various electrical appliances that need to be isolated. One end of the thyristor is connected to an electric load, such as a water inlet solenoid valve, which can also be one or more other Electrical appliances, so as to achieve a safe switching action. Moreover, in the prior art, the isolated trigger circuit of the thyristor needs to add more independent power supplies or more rectifier bridges when controlling multiple thyristors, so that the circuit load cost is relatively high. The circuit provided by the utility model can Simultaneously isolate and control multiple thyristors, the circuit is simple and the cost is low.

Preferably, the thyristor isolation trigger circuit provided by the utility model also includes a zero-crossing detection circuit, which is connected to the front of the control signal for detecting the zero-crossing point of the alternating current. Those skilled in the art are familiar with various zero-crossing detection circuits, and here Its specific circuit structure will not be repeated here. The control signal IC102 (11) of the MCU will only give a low-voltage pulse signal when it detects the zero-crossing point. In this way, the power of the power supply Power_M can be made smaller, so that the resistance of the voltage-dividing resistor series R53 and R54 The value can be larger, thereby reducing the standby power consumption of the circuit and improving the efficiency of the overall circuit.

In summary, the isolation trigger circuit provided by the utility model has the following advantages:

1. The circuit is simple and the cost is low. This solution does not need to use bidirectional phototronic thyristor (solid state relay), just use a transistor coupler, and it does not need to provide an additional isolated power supply and transformer on the output side, and does not require a rectifier bridge, which relies on the AC input side to obtain The non-isolated power supply and its unique circuit structure realize the isolation control of the thyristor, and the components of the whole circuit are few and cheap.

2. It can conveniently isolate and control multiple thyristors at the same time.

The above descriptions are only preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present utility model shall be included in this utility model. within the scope of protection of utility models.

Claims (6)

1. a silicon controlled insulation triggering circuit is characterized in that, comprises diode D51, resistance R 51, R52, R53, voltage stabilizing part, capacitor C 51, transistors couple device U51, reaches bidirectional triode thyristor TR51; The T2 utmost point of bidirectional triode thyristor TR51 links to each other with an end of AC power and the anode of diode D51 by load simultaneously, and its T1 utmost point connects the other end of AC power; The negative electrode of diode D51 connects the collector electrode of the triode of transistors couple device by resistance R 53; The anode of the diode of transistors couple device connects dc power output end, and its negative electrode links to each other with control signal output ends by resistance R 52, and the emitter of the triode of transistors couple device connects the G utmost point of bidirectional triode thyristor TR51 by resistance R 51; Be connected in after voltage stabilizing part and capacitor C 51 are in parallel between the T1 utmost point of the collector electrode of triode of transistors couple device and bidirectional triode thyristor.

2. insulation triggering circuit as claimed in claim 1 is characterized in that, described voltage stabilizing part is resistance or voltage-stabiliser tube.

3. insulation triggering circuit as claimed in claim 1 is characterized in that, described capacitor C 51 is a polar capacitor, and its positive pole links to each other with the collector electrode of the triode of transistors couple device, and its negative pole extremely links to each other with the T1 of bidirectional triode thyristor.

4. a silicon controlled insulation triggering circuit is characterized in that, comprises diode D51, resistance R 51, R52, R53, voltage stabilizing part, capacitor C 51, transistors couple device U51, reaches one-way SCR TR51; The anode of one-way SCR TR51 links to each other with an end of AC power and the anode of diode D51 by load simultaneously, and its negative electrode connects the other end of AC power; The negative electrode of diode D51 connects the collector electrode of the triode of transistors couple device by resistance R 53; The anode of the diode of transistors couple device connects dc power output end, its negative electrode links to each other with control signal output ends by resistance R 52, the emitter of the triode of transistors couple device, is connected in after voltage stabilizing part and capacitor C 51 are in parallel between the negative electrode of the collector electrode of triode of transistors couple device and one-way SCR to the silicon controlled gate pole by resistance R 51 orders.

5. insulation triggering circuit as claimed in claim 4 is characterized in that, described voltage stabilizing part is resistance or voltage-stabiliser tube.

6. insulation triggering circuit as claimed in claim 4 is characterized in that, described capacitor C 51 is a polar capacitor, and its positive pole links to each other with the collector electrode of the triode of transistors couple device, and its negative pole links to each other with the negative electrode of one-way SCR.

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