A single-phase AC zero-crossing switch controller

Abstract

The present invention provides a single-phase AC zero-crossing switch controller. The controller circuit includes a bidirectional thyristor (TRIAC) U1, an optocoupler (U2), a unidirectional thyristor (U3), a manual switch (S), resistors (R1-R5), diodes (D1-D3), transistors (Q1-Q2), and external terminals (J1-J4). While the user can close or open the manual switch (S) at any time, the controller only closes or opens the switch when the AC voltage approaches 0V. This reduces the risk of instantaneous surge current in the load circuit, effectively preventing arcing and extending the electrical life of the switch. This is crucial for safe electricity use.

Description

Technical Field

[0001] The present invention relates to a switch controller, in particular to a single-phase AC zero-crossing switch controller, belonging to the technical field of electronics. Background Art

[0002] When the load electrical appliance uses single-phase industrial frequency AC power, the time when the ordinary mechanical switch is closed or opened is basically random. The load voltage waveform after using the ordinary mechanical switch is as follows: Figure 1 As shown. If the switch is closed or opened at a large value of the AC voltage, or even at the peak of the AC voltage, it is easy to generate instantaneous surge current and arcing, thereby reducing the electrical service life of the switch equipment and posing a safety hazard to the user. Research has shown that when the AC voltage is at the zero-crossing point of the positive and negative half-cycle conversion, that is, when the AC voltage is close to 0V, the circuit is closed or disconnected, that is, the load is connected or disconnected at the zero-crossing moment, which can effectively avoid the possibility of instantaneous surge current and arcing. Therefore, it is necessary to design a single-phase AC zero-crossing switch controller, which only performs closing or disconnecting actions when the AC voltage is close to 0V. In this way, the load electrical circuit is not prone to instantaneous surge current, can effectively avoid the possibility of arcing, and can increase the electrical life of the switch body, which is of great significance to people's safe use of electricity. Summary of the Invention

[0003] In order to solve the above problems, the present invention provides a single-phase AC zero-crossing switch controller. The user can close or open the manual switch S at any time. However, the controller only performs the closing or opening action when the AC voltage is close to 0V, that is, the bidirectional thyristor U1 is triggered to turn on or off when the AC voltage is close to 0V. The load voltage waveform after using the zero-crossing switch controller is as follows: Figure 2 As shown in the figure, the load electrical circuit is less likely to generate instantaneous surge current, which can effectively avoid the possibility of arcing and extend the electrical life of the switch body, which is of great significance to people's safe use of electricity.

[0004] The specific technical solutions adopted by the present invention are as follows:

[0005] A single-phase AC zero-crossing switch controller is characterized in that: the controller circuit includes a bidirectional thyristor U1, an optical coupler U2, a unidirectional thyristor U3, a manual switch S, resistors R1 to R5, diodes D1 to D3, transistors Q1 to Q2, and external terminals J1 to J4, wherein the T1 terminal of the bidirectional thyristor U1 is connected to the external terminal J4, the T2 terminal is connected to one end of the resistor R5 and the external terminal J2, and the control electrode is connected to pin 4 of the optical coupler U2; pin 6 of the optical coupler U2 is connected to the other end of the resistor R5, pin 2 is grounded, and pin 1 is connected to the cathode of the unidirectional thyristor U3; the anode of the unidirectional thyristor U3 is connected to one end of the resistor R4, and the control electrode of the unidirectional thyristor U3 is connected to the cathode of the unidirectional thyristor U3. Connect one end of resistor R3 to the collector of transistor Q2; the base of transistor Q2 is connected to the cathode of diode D2, the emitter is connected to the anode of diode D3, the cathode of diode D3 is connected to one end of resistor R1 and external terminal J2, the anode of diode D2 is connected to one end of resistor R2, and the other end of resistor R2 is grounded; the collector of transistor Q1 is connected to the other end of resistor R3, the emitter and one end of manual switch S are connected to +5V, the base is connected to the anode of diode D1, the cathode of diode D1 is connected to the other end of resistor R1, and the other end of manual switch S is connected to the other end of resistor R4; external terminals J1 and J3 are connected to the neutral line, and external terminal J2 is connected to the phase line. The bidirectional thyristor U1 uses Q8025N5, the optocoupler U2 uses MOC3053, and the unidirectional thyristor U3 uses MCR100-8.

[0006] The beneficial effects of the present invention are as follows: the user can close or open the manual switch S at any time, but the controller performs the closing or opening action only when the AC voltage is close to 0V, that is, the bidirectional thyristor U1 is triggered to turn on or off when the AC voltage is close to 0V. In this way, the load electrical circuit is not prone to instantaneous impact current, the possibility of arc generation can be effectively avoided, and the electrical life of the switch body can be improved, which is of great significance to people's safe use of electricity. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 This is the load voltage waveform after using an ordinary mechanical switch.

[0008] Figure 2 This is the load voltage waveform after using the zero-crossing switching controller.

[0009] Figure 3 1 is a circuit diagram of the present invention. Implementation Method

[0010] The present invention will be further described below with reference to the accompanying drawings.

[0011] like Figure 3As shown, a single-phase AC zero-crossing switch controller is characterized in that: the controller circuit includes a bidirectional thyristor U1, an optocoupler U2, a unidirectional thyristor U3, a manual switch S, resistors R1 to R5, diodes D1 to D3, transistors Q1 to Q2, and external terminals J1 to J4, wherein the T1 terminal of the bidirectional thyristor U1 is connected to the external terminal J4, the T2 terminal is connected to one end of the resistor R5 and the external terminal J2, and the control electrode is connected to pin 4 of the optocoupler U2; pin 6 of the optocoupler U2 is connected to the other end of the resistor R5, pin 2 is grounded, and pin 1 is connected to the cathode of the unidirectional thyristor U3; the anode of the unidirectional thyristor U3 is connected to one end of the resistor R4, and the control electrode of the unidirectional thyristor U3 is connected to the cathode of the unidirectional thyristor U3. The base of transistor Q2 is connected to one end of resistor R3 and the collector of transistor Q2; the base of transistor Q2 is connected to the cathode of diode D2, the emitter is connected to the anode of diode D3, the cathode of diode D3 is connected to one end of resistor R1 and external terminal J2, the anode of diode D2 is connected to one end of resistor R2, and the other end of resistor R2 is grounded; the collector of transistor Q1 is connected to the other end of resistor R3, the emitter and one end of manual switch S are connected to +5V, the base is connected to the anode of diode D1, the cathode of diode D1 is connected to the other end of resistor R1, and the other end of manual switch S is connected to the other end of resistor R4; external terminals J1 and J3 are connected to the neutral line, and external terminal J2 is connected to the phase line. The bidirectional thyristor U1 uses Q8025N5, the optocoupler U2 uses MOC3053, and the unidirectional thyristor U3 uses MCR100-8.

[0012] Bidirectional thyristor U1 uses Q8025N5, packaged in TO-263-3, with a gate trigger voltage (V-GT) of 1.3V, a gate trigger current (I-GT) of 50mA, an on-state root mean square current (IT-RMS) of 25A, a holding current (IH) of 100mA, and an off-state repetitive peak voltage (V-DRM) of 800V. Optocoupler U2 uses MOC3053, packaged in DIP6, with a maximum input forward current of 60mA, a maximum input forward voltage of 1.5V, an off-state peak voltage of 600V, an output drive withstand voltage of 240V AC, and an output drive current of 100mA. Unidirectional thyristor U3 uses MCR100-8, packaged in TO-92, with a gate trigger current of less than 200uA, a gate trigger voltage of 0.8V, and an on-state voltage drop of V TM The off-state repetitive peak voltage (V-DRM) is 1.5V and 600V.

[0013] The working principle of this single-phase AC zero-crossing switch controller is: the external terminals J3 and J4 are used to connect external load electrical appliances, and the bidirectional thyristor U1 is responsible for controlling the on-off between the load electrical appliances and the phase line. When the manual switch S is closed, the bidirectional thyristor U1 is triggered to turn on only when the AC voltage is close to 0V, so that the load electrical appliances are powered and work normally; when the manual switch S is opened, the bidirectional thyristor U1 is turned off only when the AC voltage is close to 0V, and the load electrical appliances will lose power and stop working.

[0014] When the manual switch S is closed, the AC power is in the positive half cycle and the instantaneous voltage value is large, the emitter and base of the transistor Q1 cannot be turned on through the diode D1 and the resistor R1, and the transistor Q1 will work in the cut-off state. The control electrode of the one-way thyristor U3 has no trigger voltage, the one-way thyristor U3 is cut off, there is no current at the input end of the optocoupler U2, the output end of the optocoupler U2 is in a high-resistance state, the bidirectional thyristor U1 will work in the cut-off state, and the load electrical appliance and the phase line remain disconnected.

[0015] When the manual switch S is closed, the AC power is in the negative half cycle and the instantaneous voltage value is large, the base and emitter of the transistor Q2 can be turned on through the ground, resistor R2, diodes D2 and D3, and the transistor Q2 operates in the saturated conduction state. The control electrode voltage of the one-way thyristor U3 will be pulled to a low potential, that is, the control electrode of the one-way thyristor U3 cannot obtain the required forward trigger voltage, and the one-way thyristor U3 will operate in the cut-off state. There is no current at the input end of the optocoupler U2, and the output end of the optocoupler U2 is in a high-resistance state. The bidirectional thyristor U1 will operate in the cut-off state, and the load electrical appliance and the phase line remain disconnected.

[0016] When the manual switch S is closed, only when the instantaneous voltage value of the AC power is close to 0V, the transistor Q2 works in the cut-off state, the emitter and base of the transistor Q1 can be turned on through the diode D1 and the resistor R1, and the transistor Q1 works in the saturated conduction state. The +5V passes through the resistor R3 to make the control electrode of the unidirectional thyristor U3 obtain the required forward trigger voltage, the unidirectional thyristor U3 is turned on, the input end of the optocoupler U2 obtains the working current, the output end of the optocoupler U2 is in a low-resistance state, and the output end of the optocoupler U2 and the resistor R5 form a path, the bidirectional thyristor U1 will be triggered to turn on, thereby realizing the closing action of the switch controller when the AC voltage is close to 0V.

[0017] When the manual switch S is disconnected, the unidirectional thyristor U3 is cut off, there is no current at the input end of the optocoupler U2, the output end of the optocoupler U2 is in a high-resistance state, and the bidirectional thyristor U1 will not be triggered. The bidirectional thyristor U1 will automatically turn off when the AC voltage passes through zero, thereby realizing the disconnection action of the switch controller when the AC voltage is close to 0V.

Claims

1. A single-phase AC zero-crossing switch controller, characterized by: The circuit of the controller includes bidirectional thyristor U1, optocoupler U2, unidirectional thyristor U3, manual switch S, resistors R1~R5, diodes D1~D3, transistors Q1~Q2, external terminals J1~J4, bidirectional thyristor U1 uses Q8025N5, optocoupler U2 uses MOC3053, unidirectional thyristor U3 uses MCR100-8, among which T1 of bidirectional thyristor U1 is connected to external terminal J4, and T2 is connected to resistor One end of R5 is connected to the external terminal J2, and the control electrode is connected to the 4th pin of the optocoupler U2; the 6th pin of the optocoupler U2 is connected to the other end of the resistor R5, the 2nd pin is grounded, and the 1st pin is connected to the cathode of the thyristor U3; the anode of the thyristor U3 is connected to one end of the resistor R4, and the control electrode of the thyristor U3 is connected to one end of the resistor R3 and the collector of the transistor Q2; the base of the transistor Q2 is connected to the cathode of the diode D2, the emitter is connected to the anode of the diode D3, and the cathode of the diode D3 Connect one end of resistor R1 to external terminal J2, the anode of diode D2 to one end of resistor R2, and the other end of resistor R2 to ground; the collector of transistor Q1 is connected to the other end of resistor R3, the emitter and one end of manual switch S are connected to +5V, the base is connected to the anode of diode D1, the cathode of diode D1 is connected to the other end of resistor R1, and the other end of manual switch S is connected to the other end of resistor R4; external terminals J1 and J3 are connected to the neutral line, and external terminal J2 is connected to the phase line; the connection between external terminals J3 and J4 is used for external load electrical appliances, and bidirectional thyristor U1 is responsible for controlling the on-off connection between the load electrical appliances and the phase line. When manual switch S is closed, bidirectional thyristor U1 is triggered to turn on only when the AC voltage is close to 0V, and the load electrical appliances are therefore powered and operate normally; when manual switch S is opened, bidirectional thyristor U1 is turned off only when the AC voltage is close to 0V, and the load electrical appliances will lose power and stop operating.

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