A thyristor drive circuit for driving an automatic transfer switch

Abstract

The utility model discloses a kind of thyristor drive circuits for driving automatic transfer switch, the automatic transfer switch is used to selectively connect normal power supply or standby power supply to load, the thyristor drive circuit includes normal power supply side thyristor drive circuit and standby power supply side thyristor drive circuit, and the normal power supply side thyristor drive circuit and standby power supply side thyristor drive circuit independently include: automatic / manual selection unit, voltage level detection circuit unit, gate on-circuit unit, holding circuit unit, timing switch circuit unit, gate off-circuit unit, the timing switch circuit unit is connected in parallel with the gate off-circuit unit in thyristor gate.The utility model not only can effectively solve the problem of thyristor misdirect on, can guarantee that automatic transfer switch can reliably, safely operate under any working condition, and circuit structure is simple, can significantly reduce the manufacturing cost and maintenance cost of drive circuit.

Description

Technical Field

[0001] This utility model relates to a thyristor driving circuit, specifically a thyristor driving circuit for driving an automatic transfer switch. Background Technology

[0002] Typically, large buildings, factories, and hospitals use mains power as their primary power source. When mains power fails or other abnormalities occur, backup power is supplied by generators installed within the building. These large buildings, factories, and hospitals are equipped with automatic power switching systems. These systems include a distribution panel that connects the normal power supply (NP) to the load power (LP), supplying power from the normal power supply to the load. The automatic transfer switch (ATS) is the core device for automatic power switching. When the normal power supply fails, the ATS switches its main contacts, connecting the emergency power supply (EP) to the load, thus providing backup power to the load and ensuring the continuous operation of critical equipment. Once the normal power supply is restored, it automatically switches back to the normal power supply.

[0003] Figure 1 This is the circuit diagram of a traditional automatic power switching device. Figure 1 As shown, the conventional automatic power transfer device 10 connects the primary power supply (NP) 1 or the backup power supply (EP) 2 via an automatic transfer switch 4 to supply power to the load (LP) 3. The switching action of the automatic transfer switch 4 is driven by a solenoid coil (SC) 5, which is driven and controlled by the thyristor conduction controlled by the control unit 6 and the drive circuit 7.

[0004] Figure 2 This is a schematic diagram of an existing thyristor drive circuit used to drive automatic transfer switches. Figure 2 As shown, by controlling the conduction of the gates of thyristors S1 to S4 through the control unit 6 and the drive circuit 7, automatic switching between the main power supply and the backup power supply can be achieved.

[0005] However, existing thyristor drive circuits have the following technical problems:

[0006] Although the selected thyristors meet the standard withstand voltage performance, if the rate of voltage rise (dV / dt) across the thyristor switching element is large, or the turn-on voltage is lower than the applied voltage, or severe noise is generated at the thyristor gate terminals, abnormal conduction of the thyristor may occur. This can lead to malfunction of the automatic transfer switch 4, severely affecting the reliability of the power supply. Furthermore, traditional circuits often use mechanical relays to detect abnormalities in the mains power supply, and these circuits themselves are prone to failure. Additionally, the inherent failures of these thyristors can also reduce the reliability of the power supply to the automatic transfer switch 4 and the load 3 side. Utility Model Content

[0007] To address the aforementioned problems, the purpose of this invention is to provide a thyristor drive circuit for driving automatic transfer switches that can effectively prevent thyristors from being falsely turned on due to instantaneous voltage changes (dV / dt) or noise interference, thereby ensuring the stable and reliable operation of the automatic transfer switch and reducing manufacturing costs.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A thyristor driving circuit for driving an automatic transfer switch, the automatic transfer switch being used to selectively connect a primary power supply or a backup power supply to a load, the thyristor driving circuit including a primary power supply side thyristor driving circuit and a backup power supply side thyristor driving circuit, each of the primary power supply side thyristor driving circuit and the backup power supply side thyristor driving circuit independently comprising:

[0010] Automatic / manual selection unit for selecting the circuit operating mode;

[0011] A voltage level detection circuit unit is used to detect whether the power supply voltage is higher than a preset threshold.

[0012] A gate-on circuit unit is used to generate a thyristor gate drive signal when the conduction condition is met;

[0013] A holding circuit unit is used to filter and hold the generated thyristor gate drive signal;

[0014] A timed switch circuit unit is used to connect the signal output by the holding circuit unit to the gate of the thyristor and keep it on for a specified time;

[0015] A gate disconnect circuit unit is used to disconnect the thyristor gate drive signal after a predetermined time;

[0016] Furthermore, the timing switch circuit unit and the gate disconnect circuit unit are connected in parallel to the thyristor gate.

[0017] In one embodiment, the commonly used power supply side thyristor driving circuit further includes a commonly used power supply detection circuit unit for detecting the commonly used power supply, wherein the commonly used power supply detection circuit unit is electrically connected to the voltage level detection circuit unit and the gate connection circuit unit in the commonly used power supply side thyristor driving circuit, respectively.

[0018] In one embodiment, the commonly used power supply detection circuit unit is composed of an optocoupler connected in series with its external resistor.

[0019] In one embodiment, the backup power supply side thyristor drive circuit further includes a common power supply linkage circuit unit for detecting and linking the common power supply, wherein the common power supply linkage circuit unit is electrically connected to the voltage level detection circuit unit and the gate connection circuit unit in the backup power supply side thyristor drive circuit, respectively.

[0020] In one embodiment, the commonly used power supply linkage circuit unit is composed of an optocoupler.

[0021] In one embodiment, the voltage level detection circuit unit is composed of an electrolytic capacitor, a Zener diode, a first filter capacitor, and a first NPN transistor, wherein: the positive terminal of the electrolytic capacitor and the negative terminal of the Zener diode are connected in parallel to the voltage input terminal; the positive terminal of the Zener diode is connected to the base of the first NPN transistor; one end of the first filter capacitor is connected to the node between the positive terminal of the Zener diode and the base of the first NPN transistor; the negative terminal of the electrolytic capacitor, the other end of the first filter capacitor, and the emitter of the first NPN transistor are all grounded.

[0022] In one embodiment, the gate-on circuit unit is composed of a first resistor, a second resistor, and a PNP transistor, wherein: the emitter of the PNP transistor is connected to the voltage input terminal, the first resistor is connected between the emitter and base of the PNP transistor, and the second resistor is connected between the voltage output terminal of the voltage level detection circuit unit and the base of the PNP transistor.

[0023] In one embodiment, the holding circuit unit is composed of a third resistor, one end of which is connected to the node between the gate-on circuit unit and the thyristor gate, and the other end of which is connected to the voltage level detection circuit unit.

[0024] In one embodiment, the timing switch circuit unit is composed of a fourth resistor, a fifth resistor, a sixth resistor, a second filter capacitor, and a second NPN transistor. One end of the fourth resistor and one end of the fifth resistor are connected in parallel to the voltage output terminal of the holding circuit unit. The other end of the fourth resistor is connected to the gate of the thyristor. One end of the sixth resistor and one end of the second filter capacitor are connected in parallel to the other end of the fifth resistor. The other end of the sixth resistor is connected to the base of the second NPN transistor. The other end of the second filter capacitor and the emitter of the second NPN transistor are grounded together. The collector of the second NPN transistor is connected to the node between the fourth resistor and the voltage input terminal of the gate disconnect circuit unit.

[0025] In one embodiment, the gate disconnect circuit unit consists of a miniature switch and a diode connected in series, one end of which is connected to the gate of the thyristor, and the other end is grounded.

[0026] In a further implementation scheme, the anode of the diode is connected to the gate of the thyristor, the cathode of the diode is connected to one end of the microswitch, and the other end of the microswitch is grounded.

[0027] In a further implementation scheme, one end of the microswitch is connected to the gate of the thyristor, and the other end of the microswitch is connected to the anode of the diode, while the cathode of the diode is grounded.

[0028] Compared with the prior art, the beneficial technical effects of this utility model are as follows:

[0029] 1) Because the thyristor drive circuit described in this utility model is provided with a holding circuit unit and a timing switch circuit unit with self-holding characteristics, it can stably maintain the gate signal of the thyristor within a predetermined time, which can effectively resist external noise interference and reduce the maintenance cost of the drive circuit.

[0030] 2) Because the thyristor drive circuit described in this utility model is provided with a gate disconnect circuit unit, the gate signal can be reliably disconnected after the thyristor completes the conduction action. Therefore, it can effectively solve the problem of thyristor mis-conduction caused by external noise or external voltage change (dV / dt), and can greatly improve the operational reliability of the drive circuit and automatic transfer switch.

[0031] 3) Since the thyristor driving circuit described in this utility model uses an optocoupler to detect the power supply status, the circuit design is simplified and the manufacturing cost of the driving circuit can be significantly reduced. Attached Figure Description

[0032] Figure 1 This is a circuit diagram of a traditional automatic power switching device;

[0033] Figure 2This is a schematic diagram of an existing thyristor drive circuit used to drive automatic transfer switches;

[0034] Figure 3 This is a structural block diagram showing the thyristor driving circuit described in an embodiment of the present invention;

[0035] Figure 4 This is a circuit structure diagram showing the thyristor driving circuit described in an embodiment of the present invention;

[0036] Figure 5 This is a schematic diagram illustrating the working principle of the micro switch described in this embodiment of the present invention.

[0037] The labels in the diagram are as follows:

[0038] 1. Primary power supply (NP); 2. Backup power supply (EP); 3. Load (LP); 4. Automatic transfer switch; 5. Solenoid coil (SC); 6. Control unit; 7. Drive circuit; 10. Conventional power supply automatic switching device;

[0039] 100. Common power supply side thyristor drive circuit; 100-1. Common power supply side automatic / manual selection unit; 100-2. Common power supply side gate turn-on circuit unit; 100-3. Common power supply detection circuit unit; 100-4. Common power supply side voltage level detection circuit unit; 100-5. Common power supply side holding circuit unit; 100-6. Common power supply side timer switch circuit unit; 100-7. Common power supply side gate turn-off circuit unit; 100-8. Common power supply side thyristor; 200. Backup power supply side thyristor drive circuit; 200-1, Backup power supply side automatic / manual selection unit; 200-2, Backup power supply side gate turn-on circuit unit; 200-3, Normal power supply linkage circuit unit; 200-4, Backup power supply side voltage level detection circuit unit; 200-5, Backup power supply side holding circuit unit; 200-6, Backup power supply side timer switch circuit unit; 200-7, Backup power supply side gate turn-off circuit unit; 200-8, Backup power supply side thyristor; 300, Micro switch. Detailed Implementation

[0040] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. However, in order to clarify the main points of the present invention, descriptions of known functions or structures will be omitted.

[0041] Example

[0042] Depend on Figure 3As shown in the figure: This embodiment provides a thyristor driving circuit for driving an automatic transfer switch, including a mains power supply side thyristor driving circuit 100 and a backup power supply side thyristor driving circuit 200. Both the mains power supply side thyristor driving circuit 100 and the backup power supply side thyristor driving circuit 200 independently include:

[0043] Automatic / manual selection unit 100-1 / 200-1 is used to select the circuit operating mode, which can be either automatic or manual mode;

[0044] Voltage level detection circuit unit 100-4 / 200-4 is used to detect whether the voltage of the main power supply / backup power supply is higher than a preset threshold.

[0045] Gate turn-on circuit unit 100-2 / 200-2 is used to generate thyristor gate drive signal when the turn-on condition is met;

[0046] The holding circuit unit 100-5 / 200-5 is used to filter and hold the generated thyristor gate drive signal;

[0047] The timer switch circuit unit 100-6 / 200-6 is used to connect the signal output by the holding circuit unit to the gate of the thyristor and keep it on for a specified time.

[0048] Gate disconnect circuit unit 100-7 / 200-7 is used to disconnect the thyristor gate drive signal after a predetermined time;

[0049] Furthermore, the timing switch circuit unit 100-6 / 200-6 and the gate disconnect circuit unit 100-7 / 200-7 are connected in parallel to the gate of the thyristor 100-8 / 200-8.

[0050] In addition, by Figure 3It can also be seen that the commonly used power supply side thyristor drive circuit 100 further includes a commonly used power supply detection circuit unit 100-3 for detecting the presence of the commonly used power supply voltage. The commonly used power supply detection circuit unit 100-3 is electrically connected to the voltage level detection circuit unit 100-4 and the gate connection circuit unit 100-2 in the commonly used power supply side thyristor drive circuit 100. The backup power supply side thyristor drive circuit 200 further includes a commonly used power supply linkage circuit unit 200-3 for detecting and linking the commonly used power supply. The commonly used power supply linkage circuit unit 200-3 is electrically connected to the voltage level detection circuit unit 200-4 and the gate connection circuit unit 200-2 in the backup power supply side thyristor drive circuit 200. The common power supply linkage circuit unit 200-3 is a core feature unit in the thyristor drive circuit described in this utility model. This unit will be linked according to the signal detected by the common power supply detection circuit unit 100-3. If the common power supply detection circuit unit 100-3 detects that the common power supply is normal, the linkage unit will not generate a control signal, thereby preventing the backup power supply from supplying power to the load. Only when the common power supply detection circuit unit 100-3 detects that the common power supply is abnormal will the unit generate a signal to start the backup power supply side thyristor drive circuit 200.

[0051] Please see again. Figure 4 As shown:

[0052] The voltage level detection circuit unit 100-4 / 200-4 is composed of an electrolytic capacitor C5 / C11, a Zener diode ZD1 / ZD2, a first filter capacitor C4 / C10, and a first NPN transistor Q8 / Q10. Specifically: the positive terminal of the electrolytic capacitor C5 / C11 is connected in parallel with the negative terminal of the Zener diode ZD1 / ZD2 at the voltage input terminal; the positive terminal of the Zener diode ZD1 / ZD2 is connected to the base of the first NPN transistor Q8 / Q10; one end of the first filter capacitor C4 / C10 is connected to the node between the positive terminal of the Zener diode ZD1 / ZD2 and the base of the first NPN transistor Q8 / Q10; the negative terminal of the electrolytic capacitor C5 / C11, the other end of the first filter capacitor C4 / C10, and the emitter of the first NPN transistor Q8 / Q10 are all grounded.

[0053] The gate-on circuit unit 100-2 / 200-2 is composed of a first resistor R6 / R24, a second resistor R5 / R25, and a PNP transistor Q7 / Q9. Specifically: the emitter of the PNP transistor Q7 / Q9 is connected to the voltage input terminal; the first resistor R6 / R24 is connected between the emitter and base of the PNP transistor Q7 / Q9; and the second resistor R5 / R25 is connected between the voltage output terminal of the voltage level detection circuit unit (in this embodiment, the collector of the first NPN transistor Q8 / Q10) and the base of the PNP transistor Q7 / Q9.

[0054] The holding circuit units 100-5 / 200-5 are both composed of a third resistor R4 / R26. One end of the third resistor R4 / R26 is connected to the node between the gate turn-on circuit unit 100-2 / 200-2 and the gate of the thyristor 100-8 / 200-8, and the other end of the third resistor R4 / R26 is connected to the voltage level detection circuit unit 100-4 / 200-4. Specifically, in this embodiment, one end of the third resistor R4 / R26 is connected to the base of the first NPN transistor Q8 / Q10, and the other end of the third resistor R4 / R26 is connected to the collector of the PNP transistor Q7 / Q9.

[0055] The timing switch circuit unit 100-6 / 200-6 is composed of a fourth resistor R1 / R21, a fifth resistor R3 / R23, a sixth resistor R2 / R22, a second filter capacitor C3 / C9, and a second NPN transistor Q3 / Q6. One end of the fourth resistor R1 / R21 and one end of the fifth resistor R3 / R23 are connected in parallel to the voltage output terminal node of the holding circuit unit 100-5 / 200-5 (in this embodiment, this is the node between the third resistor R4 / R26 and the gate of the thyristor 100-8 / 200-8). The other end of the fourth resistor R1 / R21 is connected to the gate of the thyristor 100-8 / 200-8. The gates of 0-8 / 200-8 are connected together. One end of the sixth resistor R2 / R22 and one end of the second filter capacitor C3 / C9 are connected in parallel to the other end of the fifth resistor R3 / R23. The other end of the sixth resistor R2 / R22 is connected to the base of the second NPN transistor Q3 / Q6. The other end of the second filter capacitor C3 / C9 and the emitter of the second NPN transistor Q3 / Q6 are grounded together. The collector of the second NPN transistor Q3 / Q6 is connected to the node between the fourth resistor R1 / R21 and the voltage input terminal of the gate disconnect circuit unit 100-7 / 200-7.

[0056] The gate disconnect circuit unit 100-7 / 200-7 is composed of a miniature switch CN4 / CN8 and a diode D4 / D11 connected in series. One end of CN4 / CN8 (shown as the anode of diode D4 / D11 in the figure) is connected to the gate of thyristor 100-8 / 200-8, and the other end of CN4 / CN8 (shown as the anode of the other end of miniature switch CN4 / CN8 in the figure) is grounded. However, it can also be replaced by connecting one end of miniature switch CN4 / CN8 to the gate of thyristor 100-8 / 200-8, connecting the other end of miniature switch CN4 / CN8 to the anode of diode D4 / D11, and grounding the cathode of diode D4 / D11. Those skilled in the art will fully understand that this transformation can exhibit the same characteristics.

[0057] In addition, by Figure 4 As shown, the common power supply detection circuit unit 100-3 is composed of an optocoupler PC1 / A connected in series with its external resistors (R10 and R11 shown in the figure); the common power supply linkage circuit unit 200-3 is composed of an optocoupler PC1 / B. This invention, by using optocouplers PC1 / A and PC1 / B to detect the input-side power supply status, not only improves system safety but also simplifies circuit design and significantly reduces the manufacturing cost of the drive circuit.

[0058] Figure 5 This diagram illustrates the working principle of the microswitch 300 in the gate disconnect circuit unit 100-7 / 200-7 described in this embodiment. Figure 5 The external shape and drive mechanism of the automatic transfer switch are omitted. The micro switch 300 is mounted on the mechanical structure of the automatic transfer switch 4. Its pressing part is linked to the drive shaft of the automatic transfer switch (ATS). Driven by a thyristor, the drive shaft of the automatic transfer switch (ATS) moves between the main power supply side and the backup power supply side. Through this movement of the drive shaft, the pressing part of the micro switch 300 functions as a switch. Its specific working process is as follows:

[0059] Please combine Figure 4 and Figure 5As shown, when the ATS is in a non-switching state or in the process of switching, the drive shaft does not press down the microswitch 300, and the microswitch 300 is in a normally open state, so the gate disconnect circuit unit 100-7 / 200-7 does not function. When the thyristor 100-8 / 200-8 is triggered and turned on, the drive shaft starts to move. When it moves to the predetermined switching position, the protrusion on the drive shaft presses down the microswitch 300, causing its contacts to close. At this time, the gate of the thyristor 100-8 / 200-8 is directly connected to ground GND through diodes D4 / D11 and the closed microswitch 300. In this way, any noise voltage that may couple to the gate of the thyristor 100-8 / 200-8 will be bypassed by this low-impedance path, and cannot form an effective trigger voltage. At the same time, the internal displacement current generated by the dV / dt effect will also be shunted by this path, thereby completely avoiding false triggering of the thyristor 100-8 / 200-8.

[0060] In some embodiments, the micro switch 300 may also be replaced with other types of mechanical switches, such as limit switches, Hall switches, etc., as long as they can reflect the mechanical position state of the ATS.

[0061] The specific working process of the thyristor driving circuit for driving automatic transfer switches described in this utility model is as follows:

[0062] Power status detection: The common power detection circuit unit 100-3 continuously monitors the common power supply through an optocoupler. If the common power supply is normal, the relevant signal will be transmitted to the subsequent circuit. If the common power supply is abnormal (such as a power outage), the common power supply linkage circuit unit 200-3 will be triggered.

[0063] Signal generation and holding: When the voltage level detection circuit unit 100-4 / 200-4 confirms that the voltage is normal, the gate turn-on circuit unit 100-2 / 200-2 will generate a drive signal. This signal is filtered and stabilized by the holding circuit unit 100-5 / 200-5 to enhance the anti-interference capability.

[0064] Timed gate drive: The stable signal output by the holding circuit unit 100-5 / 200-5 will activate the timed switch circuit unit 100-6 / 200-6. This unit will conduct within a set time to drive the gate of the corresponding thyristor 100-8 / 200-8, making it reliably conduct. After the thyristor 100-8 / 200-8 conducts, it will drive the solenoid coil 5 in the automatic transfer switch 4 to switch it to the normal power supply / standby power supply position.

[0065] Gate reliably disconnects: such as Figure 5As shown, when the drive shaft of the automatic transfer switch 4 moves into position, it will trigger the micro switch (or trigger switch, limit switch) 300. This micro switch 300 is part of the gate disconnect circuit unit 100-7 / 200-7. The action of the micro switch 300 will turn on the gate disconnect circuit unit 100-7 / 200-7, pull the gate potential of the thyristor 100-8 / 200-8 to ground (GND), thereby forcibly cutting off the gate signal and ensuring that the thyristor 100-8 / 200-8 is in a reliable off state after completing the switching task, thereby avoiding re-conduction caused by dV / dt or noise.

[0066] The structure and working principle of the thyristor drive circuit 100 on the normal power supply side and the thyristor drive circuit 200 on the backup power supply side described in this utility model are basically similar. The only difference is that the normal power supply linkage circuit unit 200-3 on the backup power supply side is linked according to the signal detected by the normal power supply detection circuit unit 100-3 on the normal power supply side. If the normal power supply detection circuit unit 100-3 detects that the normal power supply is normal, the normal power supply linkage circuit unit 200-3 will not generate a control signal, thereby preventing the backup power supply from supplying power to the load. Only when the normal power supply detection circuit unit 100-3 detects that the normal power supply is abnormal will the normal power supply linkage circuit unit 200-3 trigger the operation of the thyristor drive circuit 200 on the backup power supply side.

[0067] As can be seen from the above, the thyristor drive circuit of this utility model first determines the power supply status, then generates a stable drive signal with timing function, and finally forcibly cuts off the gate signal after the switching action is completed. This ensures that the automatic transfer switch can operate reliably and safely under any operating conditions. It can not only effectively solve the problem of thyristor mis-conduction caused by external noise or external voltage change (dV / dt), but also has a simple circuit structure, which can significantly reduce the manufacturing and maintenance costs of the drive circuit and has obvious practical value.

[0068] Finally, it should be understood that the above embodiments are merely illustrative, and the scope of protection of this utility model is not limited thereto. Those skilled in the art will understand that various modifications and variations are possible without altering the technical concept or basic characteristics of this utility model. For example, components described as a single type can be implemented separately, and similarly, components described as separate can be implemented in combination. Therefore, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A thyristor driving circuit for driving an automatic transfer switch, the automatic transfer switch being used to selectively connect a primary power supply or a backup power supply to a load, the thyristor driving circuit comprising a primary power supply side thyristor driving circuit and a backup power supply side thyristor driving circuit, characterized in that, The commonly used power supply side thyristor drive circuit and the backup power supply side thyristor drive circuit each include independently: Automatic / manual selection unit for selecting the circuit operating mode; A voltage level detection circuit unit is used to detect whether the power supply voltage is higher than a preset threshold. A gate-on circuit unit is used to generate a thyristor gate drive signal when the conduction condition is met; A holding circuit unit is used to filter and hold the generated thyristor gate drive signal; A timed switch circuit unit is used to connect the signal output by the holding circuit unit to the gate of the thyristor and keep it on for a specified time; A gate disconnect circuit unit is used to disconnect the thyristor gate drive signal after a predetermined time; Furthermore, the timing switch circuit unit and the gate disconnect circuit unit are connected in parallel to the thyristor gate.

2. The thyristor driving circuit for driving an automatic transfer switch according to claim 1, characterized in that: The commonly used power supply side thyristor drive circuit also includes a commonly used power supply detection circuit unit for detecting the commonly used power supply. The commonly used power supply detection circuit unit is electrically connected to the voltage level detection circuit unit and the gate connection circuit unit in the commonly used power supply side thyristor drive circuit, respectively.

3. The thyristor driving circuit for driving an automatic transfer switch according to claim 1, characterized in that: The backup power supply side thyristor drive circuit also includes a common power supply linkage circuit unit for detecting and linking the common power supply. The common power supply linkage circuit unit is electrically connected to the voltage level detection circuit unit and the gate connection circuit unit in the backup power supply side thyristor drive circuit.

4. The thyristor driving circuit for driving an automatic transfer switch according to claim 1, characterized in that: The voltage level detection circuit unit is composed of an electrolytic capacitor, a Zener diode, a first filter capacitor, and a first NPN transistor, wherein: the positive terminal of the electrolytic capacitor and the negative terminal of the Zener diode are connected in parallel to the voltage input terminal; the positive terminal of the Zener diode is connected to the base of the first NPN transistor; one end of the first filter capacitor is connected to the node between the positive terminal of the Zener diode and the base of the first NPN transistor; the negative terminal of the electrolytic capacitor, the other end of the first filter capacitor, and the emitter of the first NPN transistor are all grounded.

5. The thyristor driving circuit for driving an automatic transfer switch according to claim 1, characterized in that: The gate-on circuit unit is composed of a first resistor, a second resistor, and a PNP transistor, wherein: the emitter of the PNP transistor is connected to the voltage input terminal, the first resistor is connected between the emitter and base of the PNP transistor, and the second resistor is connected between the voltage output terminal of the voltage level detection circuit unit and the base of the PNP transistor.

6. The thyristor driving circuit for driving an automatic transfer switch according to claim 1, characterized in that: The holding circuit unit is composed of a third resistor. One end of the third resistor is connected to the node between the gate turn-on circuit unit and the thyristor gate, and the other end of the third resistor is connected to the voltage level detection circuit unit.

7. The thyristor driving circuit for driving an automatic transfer switch according to claim 1, characterized in that: The timing switch circuit unit is composed of a fourth resistor, a fifth resistor, a sixth resistor, a second filter capacitor, and a second NPN transistor. One end of the fourth resistor and one end of the fifth resistor are connected in parallel to the voltage output terminal of the holding circuit unit. The other end of the fourth resistor is connected to the gate of the thyristor. One end of the sixth resistor and one end of the second filter capacitor are connected in parallel to the other end of the fifth resistor. The other end of the sixth resistor is connected to the base of the second NPN transistor. The other end of the second filter capacitor and the emitter of the second NPN transistor are grounded together. The collector of the second NPN transistor is connected to the node between the fourth resistor and the voltage input terminal of the gate disconnect circuit unit.

8. The thyristor driving circuit for driving an automatic transfer switch according to claim 1, characterized in that: The gate disconnect circuit unit consists of a miniature switch and a diode connected in series, with one end connected to the gate of the thyristor and the other end grounded.

9. The thyristor driving circuit for driving an automatic transfer switch according to claim 8, characterized in that: The anode of the diode is connected to the gate of the thyristor, the cathode of the diode is connected to one end of the micro switch, and the other end of the micro switch is grounded.

10. The thyristor driving circuit for driving an automatic transfer switch according to claim 8, characterized in that: One end of the microswitch is connected to the gate of the thyristor, and the other end of the microswitch is connected to the anode of the diode, while the cathode of the diode is grounded.

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