A trigger circuit for a thyristor

Abstract

The application discloses a thyristor trigger circuit and relates to the technical field of electronic power. The trigger circuit comprises a push-pull conversion module, an optical coupling isolation module and a power module, the push-pull conversion module comprises at least one pulse transformer; the primary coil of each pulse transformer is connected with the power module and the optical coupling isolation module respectively, and the secondary coil of each pulse transformer is connected with a thyristor. Thus, the output of strong pulse current is realized, the cost of the thyristor trigger circuit is reduced, and the volume of the thyristor trigger circuit is reduced.

Description

Technical Field

[0001] This application relates to the field of electronic power technology, and in particular to a trigger circuit for a thyristor. Background Technology

[0002] Thyristors, as semi-controlled devices, are widely used in power electronics, and their reliable conduction relies on gate triggering. However, triggering a thyristor requires a certain voltage and current, and the circuit that generates the trigger pulse often lacks sufficient driving capability. Therefore, a trigger circuit is needed to increase the driving capability of the pulse.

[0003] While traditional pulse transformer isolation schemes can achieve trigger signal coupling and isolation, they have significant shortcomings in achieving strong triggering: to output a sufficiently large pulse current, the transformer size and cost increase significantly, making it difficult to adapt to applications sensitive to size or cost; if the transformer size is reduced, the required strong pulse current cannot be provided, affecting system reliability. Therefore, current triggering schemes struggle to ensure strong triggering performance while controlling size and cost. Utility Model Content

[0004] The main objective of this application is to provide a thyristor trigger circuit to achieve strong pulse current output, reduce the cost of the thyristor trigger circuit, and reduce the size of the thyristor trigger circuit.

[0005] To achieve the above objectives, this application provides a triggering circuit for a thyristor, including a push-pull converter module, an optocoupler isolation module, and a power supply module, wherein the push-pull converter module includes at least one pulse transformer; The primary winding of each pulse transformer is connected to the power supply module and the optocoupler isolation module, respectively, and the secondary winding of each pulse transformer is connected to a thyristor.

[0006] Optionally, the pulse transformer includes a first primary coil and a second primary coil, the first primary coil and the second primary coil being connected in series; the push-pull converter module includes a switching unit, the switching unit including a first switching transistor and a second switching transistor, one end of the first primary coil being connected to the first end of the first switching transistor, the other end of the first primary coil being connected to the positive terminal of the power module, the second end of the first switching transistor being connected to the negative terminal of the power module, one end of the second primary coil being connected to the positive terminal of the power module, the other end of the second primary coil being connected to the first end of the second switching transistor, the second end of the second switching transistor being connected to the negative terminal of the power module, and the third ends of the first switching transistor and the second switching transistor being connected to the optocoupler isolation module.

[0007] Optionally, the switching unit further includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first capacitor, and a second capacitor; one end of the first resistor is connected to the optocoupler isolation module, and the other end of the first resistor is connected to the third terminal of the first switching transistor to form a first node; the second resistor and the first capacitor are connected in series and then in parallel between the first and second terminals of the first switching transistor; one end of the third resistor is connected to the optocoupler isolation module, and the other end of the third resistor is connected to the third terminal of the second switching transistor to form a second node; the fourth resistor and the second capacitor are connected in series and then in parallel between the first and second terminals of the second switching transistor; one end of the fifth resistor is connected to the first node, and the other end of the fifth resistor is connected to the first terminal of the first switching transistor to form a third node, and the third node is grounded; one end of the sixth resistor is connected to the second node, and the other end of the sixth resistor is connected to the first terminal of the second switching transistor to form a fourth node, and the fourth node is grounded.

[0008] Optionally, the push-pull converter module includes at least one rectifier output unit; one end of each rectifier output unit is connected to the secondary coil of a pulse transformer, and the other end of each rectifier output unit is connected to a thyristor.

[0009] Optionally, the pulse transformer includes a first secondary coil and a second secondary coil, which are connected in series; the rectifier output unit includes a first diode, a second diode, a first resistor subunit, and a second resistor subunit, wherein the resistance of the first resistor subunit is less than the resistance of the second resistor subunit; the anode of the first diode is connected to one end of the first secondary coil, the cathode of the first diode is connected to one end of the first resistor subunit, and the other end of the first resistor subunit is connected to the gate of the corresponding thyristor; the anode of the second diode is connected to one end of the second secondary coil, the cathode of the second diode is connected to one end of the second resistor subunit, and the other end of the second resistor subunit is connected to the gate of the corresponding thyristor; the other ends of the first secondary coil and the other ends of the second secondary coil are connected in series and then connected to the cathode of the corresponding thyristor.

[0010] Optionally, the rectifier output unit further includes a seventh resistor, a third capacitor, and a third diode; one end of the seventh resistor is connected to the gate of the corresponding thyristor, and the other end of the seventh resistor is connected to the cathode of the corresponding thyristor; one end of the third capacitor is connected to the gate of the corresponding thyristor, and the other end of the third capacitor is connected to the cathode of the corresponding thyristor; the cathode of the third diode is connected to the gate of the corresponding thyristor, and the anode of the third diode is connected to the cathode of the corresponding thyristor.

[0011] Optionally, the first resistor subunit includes an eighth resistor, a ninth resistor, and a tenth resistor, and the second resistor subunit includes an eleventh resistor; one end of the eighth resistor, the ninth resistor, and the tenth resistor are connected in parallel and connected to the cathode of the first diode, and the other end is connected to the gate of the corresponding thyristor; one end of the eleventh resistor is connected to the cathode of the second diode, and the other end of the eleventh resistor is connected to the gate of the corresponding thyristor.

[0012] Optionally, the optocoupler isolation module includes an optocoupler chip, an optocoupler input unit, and an optocoupler output unit; one end of the optocoupler input unit is connected to the system controller, and the other end of the optocoupler input unit is connected to the optocoupler chip; one end of the optocoupler output unit is connected to the optocoupler chip, and the other end of the optocoupler output unit is connected to the first switch and the second switch.

[0013] Optionally, the optocoupler input unit includes a twelfth resistor, a fourth capacitor, and a fourth diode; one end of the twelfth resistor is connected to the system controller, and the other end of the twelfth resistor is connected to the Anode pin of the optocoupler chip, forming a fourth node; one end of the fourth capacitor is connected to the fourth node, and the other end of the fourth capacitor is grounded; the cathode of the fourth diode is connected to the Anode pin of the optocoupler chip, and the anode of the fourth diode is connected to the cathode pin of the optocoupler chip and grounded.

[0014] Optionally, the optocoupler output unit includes a fifth capacitor, a sixth capacitor, a seventh capacitor, an eighth capacitor, a fifth diode, a thirteenth resistor, a first polarity capacitor, and a second polarity capacitor; the power supply pin of the optocoupler chip is connected to an external power supply, and the ground pin of the optocoupler chip is grounded; the fifth capacitor is connected in parallel between the power supply pin and the ground pin of the optocoupler chip, and the sixth capacitor is connected in parallel between the power supply pin and the ground pin of the optocoupler chip; the cathode of the fifth diode is connected to one end of the sixth capacitor, forming a fifth node, and the anode of the fifth diode is connected to the output pin of the optocoupler chip, forming a sixth node; the seventh capacitor... One end of the seventh capacitor is connected to the fifth node, and the other end of the seventh capacitor is connected to the sixth node. One end of the first polarized capacitor is connected to the fifth node, and the other end of the first polarized capacitor is connected to the sixth node. One end of the thirteenth resistor is connected to the other end of the sixth capacitor, forming the seventh node. The other end of the thirteenth resistor is connected to the output pin of the optocoupler chip, forming the eighth node. One end of the eighth capacitor is connected to the seventh node, and the other end of the eighth capacitor is connected to the eighth node. One end of the second polarized capacitor is connected to the seventh node, and the other end of the second polarized capacitor is connected to the eighth node.

[0015] The thyristor triggering circuit of this application uses multiple pulse transformers to drive and trigger the thyristor. The push-pull converter module of this embodiment is more efficient than the commonly used forward / flyback topology and requires fewer isolation drive-related components than the full-bridge circuit. Therefore, it can not only output strong pulse current, but also reduce the cost and size of the triggering circuit. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the trigger circuit according to an embodiment of this application; Figure 2 This is a circuit diagram of the push-pull converter module according to an embodiment of this application; Figure 3 This is a circuit diagram of the switching unit according to an embodiment of this application; Figure 4 This is a circuit diagram of the rectifier output unit according to an embodiment of this application; Figure 5 This is a circuit diagram of the optocoupler isolation module according to an embodiment of this application; In the diagram, 110 is the push-pull converter module; 111 is the switching unit; 112 is the rectifier output unit; 120 is the optocoupler isolation module; 121 is the optocoupler input unit; 122 is the optocoupler chip; 123 is the optocoupler output unit; and 130 is the power supply module.

[0017] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] In the field of power electronics, thyristors, also known as silicon controlled rectifiers (SCRs), are important semiconductor power devices that play a crucial role in industrial applications due to their advantages such as large current capacity and strong impact resistance. Currently, with the continuous improvement of domestic thyristor manufacturing technology, their proportion as semi-controlled devices in various power control systems is increasing, and they are widely used in AC voltage regulation, reactive power compensation, motor drives, and high-voltage direct current transmission.

[0020] For a thyristor to function properly, a trigger pulse with a certain voltage and current must be applied to its gate to turn it on. However, the trigger pulse generation circuit usually lacks sufficient driving capability, necessitating a dedicated trigger circuit for pulse amplification and isolation. Especially in the main circuit system, to improve the triggering reliability of multiple series-connected thyristors and resist false triggering interference under high-voltage conditions, a strong pulse triggering method is often used. This strong pulse triggering typically requires 5 to 10 times the normal pulse current.

[0021] Traditional solutions often use pulse transformers to achieve electrical isolation between the control circuit and the main circuit, coupling the trigger signal to the gate. While this method offers reliable triggering and wide applicability, it requires a large pulse transformer to meet the high current demand for strong triggering, resulting in high manufacturing costs. This limits its application in size- or cost-sensitive systems. Conversely, reducing the transformer size to control size and cost makes it difficult to provide sufficient pulse current, leading to decreased system reliability. Therefore, there is an urgent need to develop a novel thyristor trigger circuit that can stably output the high-current pulse required for strong triggering while maintaining a small size and low cost, thereby improving the system's economy and applicability.

[0022] Therefore, this application provides a thyristor triggering circuit. By adopting a push-pull converter topology (i.e., a push-pull converter module), it has higher triggering efficiency compared to other topologies, and the driving capability of the primary-side drive circuit of the pulse transformer is stronger. At the same time, it reduces the components required for isolation signals, thereby reducing the cost and size of the triggering circuit. In addition, this application embodiment achieves the driving of the thyristor by controlling the first pulse to reach a strong pulse current and then outputting a small current, which can effectively reduce the output power of the push-pull converter module.

[0023] Figure 1 This is a schematic diagram of the trigger circuit according to an embodiment of this application. For example... Figure 1 As shown, the trigger circuit may include a push-pull converter module 110, an optocoupler isolation module 120, and a power supply module 130. The push-pull converter module 110 includes at least one pulse transformer Tx. The primary coil of each pulse transformer Tx is connected to the power supply module 130 and the optocoupler isolation module 120, respectively, and the secondary coil of each pulse transformer Tx is connected to a thyristor.

[0024] In this embodiment, the power supply module 130 is the energy source for the entire trigger circuit, providing a stable and reliable DC operating voltage for the push-pull converter module 110 and the optocoupler isolation module 120. Specifically, the power supply module 130 can be any 24V DC power supply currently available on the market; no specific limitation is made to the power supply module 130 here.

[0025] Furthermore, the optocoupler isolation module 120 primarily serves as an electrical isolation and signal driver. Specifically, the optocoupler isolation module 120 can completely isolate the pulse signal from the system controller from the push-pull converter module 110, thereby effectively preventing high-voltage and high-current interference from the main circuit from entering the control terminal and causing the system controller chip to burn out, ensuring the safety and reliability of the system. It can be understood that the system controller is a low-voltage, low-current, and easily interfered-susceptible low-voltage system, while the push-pull converter module 110 is a high-voltage and high-current power system.

[0026] In addition, the optocoupler isolation module 120 can also perform "electric-optical-electric" conversion on the weak pulse signal sent by the system controller and output an isolation pulse signal that can effectively drive the switching transistor in the push-pull converter module 110.

[0027] In this embodiment, the push-pull converter module 110 may include one or more pulse transformers Tx, which are connected in series. The push-pull converter module 110 can chop the 24V DC power supplied by the power supply module 130 into a high-frequency AC square wave, and boost the current through the pulse transformers Tx, ultimately obtaining a large current pulse that can directly trigger the thyristor at the secondary side of the pulse transformers Tx.

[0028] In addition, the pulse transformer Tx in this embodiment can be manufactured using a planar flat PCB transformer manufacturing process. Compared with ordinary transformers, the pulse transformer Tx manufactured using this process is smaller in size, has less loss, and is cheaper, thereby further reducing the size and cost of the entire trigger circuit. When such a trigger circuit is installed in a specific product, it will also make the product smaller and cheaper.

[0029] The structure and function of the push-pull conversion module 110 and the optocoupler isolation module 120 of the trigger circuit are described in detail below.

[0030] Figure 2 This is a circuit diagram of the push-pull converter module according to an embodiment of this application. Figure 2 As shown, in some embodiments, the pulse transformer Tx in the push-pull converter module 110 may include a first primary coil and a second primary coil, with the first primary coil and the second primary coil connected in series.

[0031] The push-pull converter module 110 may include a switching unit 111, which may include a first switching transistor Q1 and a second switching transistor Q2. One end of the first primary coil is connected to the first terminal a1 of the first switching transistor Q1, and the other end of the first primary coil is connected to the positive terminal of the power supply module 130. The second terminal a2 of the first switching transistor Q1 is connected to the negative terminal of the power supply module 130. One end of the second primary coil is connected to the positive terminal of the power supply module 130, and the other end of the second primary coil is connected to the first terminal a1 of the second switching transistor Q2. The second terminal a2 of the second switching transistor Q2 is connected to the negative terminal of the power supply module 130. The third terminal a3 of the first switching transistor Q1 and the second switching transistor Q2 is connected to the optocoupler isolation module 120.

[0032] It should be noted that the first switch Q1 and the second switch Q2 in this embodiment can be NMOS switches, SiC MOS transistors, etc. This embodiment will use an NMOS switch as an example for further explanation. If the first switch Q1 and the second switch Q2 are NMOS switches, then the first terminal a1 of the first switch Q1 and the second switch Q2 can be the source, the second terminal a2 can be the drain, and the third terminal a3 can be the gate. Furthermore, the positive terminal of the power module 130 is the positive output terminal, and the negative terminal of the power module 130 is the negative output terminal.

[0033] In this embodiment, the primary side of each pulse transformer Tx consists of two coils with opposite terminals: a first primary coil and a second primary coil. For example... Figure 2 As shown, the first primary coils of each pulse transformer Tx are connected in series, the second primary coils of each pulse transformer Tx are connected in series, and the pulse transformers Tx are connected in series to divide the voltage. It is necessary to ensure that each pulse transformer Tx can receive a voltage sufficient to trigger the thyristor.

[0034] Furthermore, the first primary winding of each pulse transformer Tx is connected to the first switch Q1 and the power module 130, while the second primary winding of each pulse transformer Tx is connected to the second switch Q2 and the power module 130. The first switch Q1 and the second switch Q2 can receive equal-amplitude, complementary pulse signals emitted by the system controller and transmitted by the optocoupler isolation module 120.

[0035] When the first switch Q1 and the second switch Q2 receive the pulse signal, the first switch Q1 and the second switch Q2 are turned on, thereby turning on the primary circuit of the pulse transformer Tx, so that the power supply module 130 can output DC power to the pulse transformer Tx; finally, the secondary side of the pulse transformer Tx rectifies the DC power and outputs a drive signal sufficient to drive the thyristor.

[0036] Figure 3 This is a circuit diagram of the switching unit according to an embodiment of this application. Figure 3 As shown, in some embodiments, the switching unit 111 may further include a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a first capacitor C1, and a second capacitor C2.

[0037] In this configuration, one end of the first resistor R1 is connected to the optocoupler isolation module 120, and the other end of the first resistor R1 is connected to the third terminal of the first switch Q1 to form a first node N1; the second resistor R2 is connected in series with the first capacitor C1 and then in parallel between the first and second terminals of the first switch Q1; one end of the third resistor R3 is connected to the optocoupler isolation module 120, and the other end of the third resistor R3 is connected to the third terminal of the second switch Q2 to form a second node N2; the fourth resistor R4 is connected in series with the second capacitor C2 and then in parallel between the first and second terminals of the second switch Q2; one end of the fifth resistor R5 is connected to the first node N1, and the other end of the fifth resistor R5 is connected to the first terminal of the first switch Q1 to form a third node N3, which is grounded; one end of the sixth resistor R6 is connected to the second node N2, and the other end of the sixth resistor R6 is connected to the first terminal of the second switch Q2 to form a fourth node N4, which is grounded.

[0038] Specifically, the third terminals (gates) of the first switch Q1 and the second switch Q2 are connected to the optocoupler isolation module 120, respectively. The first switch Q1 and the second switch Q2 receive two pulse signals output by the optocoupler isolation module 120, and these two pulse signals are equal in magnitude and complementary. The second terminal (drain) of the first switch Q1 is connected to the first primary winding of each pulse transformer Tx, and the other end of the first primary winding of each pulse transformer Tx is connected to the power supply module 130. The power supply module 130 outputs 24V DC power to supply power to the entire circuit, and the first terminal (source) of the first switch Q1 is connected to 24V ground to form a circuit.

[0039] Furthermore, the first resistor R1 and the third resistor R3 are connected in series with the third terminals of the first switch Q1 and the second switch Q2, respectively. R1 and R3 limit the current, thus protecting the first and second switches Q1 and Q2. The fifth resistor R5 and the sixth resistor R6 are connected in parallel between the third and first terminals of the first and second switches Q1 and Q2, respectively. R5 and R6 are pull-down resistors used to prevent the first and second switches Q1 and Q2 from erroneously starting when the drive power is off. The first capacitor C1, the second resistor R2, the second capacitor C2, and the fourth resistor R4 all form a resistor-capacitor absorption circuit, used to absorb the voltage spikes of the first and second switches Q1 and Q2 when they are turned on, thereby further protecting the first and second switches Q1 and Q2.

[0040] In some embodiments, the push-pull converter module 110 includes at least one rectifier output unit 112; one end of each rectifier output unit 112 is connected to the secondary coil of a pulse transformer Tx, and the other end of each rectifier output unit 112 is connected to a thyristor. Specifically, the rectifier output unit 112 corresponds one-to-one with the pulse transformer Tx and the thyristor. The rectifier output unit 112 is used to convert the high-frequency AC power output by the pulse transformer Tx into a trigger signal for the thyristor through rectification, differentiated current control, and signal synthesis.

[0041] Figure 4 This is a circuit diagram of the rectifier output unit according to an embodiment of this application. Figure 4 As shown, in some embodiments, the pulse transformer Tx includes a first secondary coil and a second secondary coil, which are connected in series.

[0042] The rectifier output unit 112 includes a first diode D1, a second diode D2, a first resistor subunit, and a second resistor subunit. The resistance of the first resistor subunit is less than that of the second resistor subunit. The anode of the first diode D1 is connected to one end of the first secondary coil, the cathode of the first diode D1 is connected to one end of the first resistor subunit, and the other end of the first resistor subunit is connected to the gate G of the corresponding thyristor. The anode of the second diode D2 is connected to one end of the second secondary coil, the cathode of the second diode D2 is connected to one end of the second resistor subunit, and the other end of the second resistor subunit is connected to the gate G of the corresponding thyristor. The other end of the first secondary coil and the other end of the second secondary coil are connected in series to the cathode K of the corresponding thyristor.

[0043] In addition, the rectifier output unit 112 also includes a seventh resistor R7, a third capacitor C3, and a third diode D3.

[0044] One end of the seventh resistor R7 is connected to the gate G of the corresponding thyristor, and the other end of the seventh resistor R7 is connected to the cathode K of the corresponding thyristor; one end of the third capacitor C3 is connected to the gate G of the corresponding thyristor, and the other end of the third capacitor C3 is connected to the cathode K of the corresponding thyristor; the cathode of the third diode D3 is connected to the gate G of the corresponding thyristor, and the anode of the third diode D3 is connected to the cathode K of the corresponding thyristor.

[0045] Specifically, the opposite terminals of the first and second secondary coils of the pulse transformer Tx are directly connected and serve as the ground K for the thyristor drive signal. The same terminals of the first and second secondary coils are rectified for output. One end of the first secondary coil is connected to one output, and the other end of the second secondary coil is connected to another output. The first diode D1 rectifies the current output from the first secondary coil, and the second diode D2 rectifies the current output from the second secondary coil.

[0046] In this embodiment, the seventh resistor R7 is a voltage regulator resistor between drive signals; the third capacitor C3 is a filter capacitor, which plays a filtering role; and the third diode D3 is a freewheeling diode, which is used to prevent the signal from reversing.

[0047] In this embodiment, the resistance of the first resistor subunit can be less than the resistance of the second resistor subunit. It is understood that for a normal pulse transformer Tx, the output currents on both secondary sides of Tx are equal. If a strong pulse current is to be output, both secondary sides need to output a strong pulse current, resulting in a significant increase in the power consumption of the trigger circuit, as well as an increase in the size and cost of the pulse transformer Tx. However, the thyristor only needs the first pulse current to reach the level of a strong pulse current to trigger it to conduct. Therefore, this embodiment designs the two pulse currents output from the secondary side of the pulse transformer Tx to be divided into a large current and a small current. In practical applications, the system controller first outputs the large pulse current, then the small pulse current, to trigger the thyristor to conduct. This effectively reduces the output power of the trigger circuit and effectively controls the size and cost of the trigger circuit.

[0048] The embodiments of this application achieve the separation of two pulse currents output from the secondary side of the pulse transformer Tx into a large current and a small current by setting the first resistor subunit and the second resistor subunit to different resistance values.

[0049] like Figure 4 As shown, in some embodiments, the first resistor subunit includes an eighth resistor R8, a ninth resistor R9, and a tenth resistor R10, and the second resistor subunit includes an eleventh resistor R11. The eighth resistor R8, the ninth resistor R9, and the tenth resistor R10 are connected in parallel, with one end connected to the cathode of the first diode D1 and the other end connected to the gate G of the corresponding thyristor. One end of the eleventh resistor R11 is connected to the cathode of the second diode D2, and the other end of the eleventh resistor R11 is connected to the gate G of the corresponding thyristor.

[0050] In this embodiment, the first resistor subunit is composed of three resistors connected in parallel, and the second resistor subunit includes only one resistor. Therefore, the resistance value of the first resistor subunit is much smaller than the resistance value of the second resistor subunit. That is, the current limiting resistance value of the first diode D1 is much smaller than the current limiting resistance value of the second diode D2. Therefore, the current in the branch where the first diode D1 is located is greater than the current in the branch where the second diode D2 is located.

[0051] Since a thyristor is triggered only by the first pulse current reaching a strong pulse current level, subsequent pulse currents only need to be kept at a small pulse current sufficient to keep the thyristor conducting continuously. Based on this, this embodiment controls the magnitude of the positive and negative period pulse currents by controlling the amplitude of the positive and negative half-waves.

[0052] Specifically, in this embodiment, the resistance value of the second resistor subunit is selected to be greater than that of the first resistor subunit to control the output of a small pulse current during the negative half-cycle. The overall driving effect is as follows: the pulse transformer Tx first outputs the positive half-cycle, and the branch containing the first diode D1 outputs a large pulse current, reaching the threshold current for thyristor triggering. Because the resistance value of the first resistor subunit in this circuit is small, the current passing through it is large. Similarly, when the output of the pulse transformer Tx reaches the negative half-cycle, the branch containing the second diode D2 outputs a small pulse current to maintain the continuous conduction of the thyristor, keeping the thyristor current value much lower than the small pulse current value. Because the resistance value of the second resistor subunit in this circuit is large, the current passing through it is small. This working cycle repeats until the next complete cycle arrives.

[0053] In this way, the trigger signal output by the pulse transformer Tx is refined, and the pulse current is set to the most suitable operating condition by combining the conduction characteristics of the thyristor. This greatly reduces the driving power, and at the same time, it can effectively reduce heat generation, losses, etc., and improve the operational stability of the system.

[0054] In some implementations, a unique intermittent triggering method can also be used, where the system controller intermittently outputs trigger signals. Unlike the full-cycle wave triggering method in conventional drive schemes, this embodiment optimizes the triggering method based on the conduction and triggering characteristics of the thyristor.

[0055] Specifically, for a thyristor, which acts as a current-controlled element, triggering only requires the first pulse current to reach the threshold current within a cycle, and the current to be maintained above the thyristor's holding current in the latter half of the cycle. Moreover, this holding current is much lower than the trigger current. Therefore, when optimizing power using current-limiting resistors of different values, the CPU's waveform generation strategy is adjusted: the trigger pulse signal generated throughout the entire cycle is reduced to one-tenth of its original amount; that is, the pulse drive signal is generated for only one-tenth of the time in a cycle, and waveform generation is stopped for the remaining nine-tenths of the time. As long as it is ensured that the thyristor receives a sufficient conduction pulse current when the first trigger pulse signal arrives, the system controller stops waveform generation in subsequent cycles, reducing the power consumption of the entire cycle.

[0056] Therefore, by intermittently transmitting waves, the average power of the entire cycle is reduced to one-tenth of that of the full-wave cycle, transforming the average power consumption of the entire cycle into instantaneous power consumption, further reducing unnecessary power loss. Combined with different current-limiting resistors, this achieves the goal of reducing output power.

[0057] Figure 5 This is a circuit diagram of the optocoupler isolation module according to an embodiment of this application.

[0058] like Figure 5As shown, in some embodiments, the optocoupler isolation module 120 may include an optocoupler chip 122, an optocoupler input unit 121, and an optocoupler output unit 123. One end of the optocoupler input unit 121 is connected to the system controller, and the other end is connected to the optocoupler chip 122. One end of the optocoupler output unit 123 is connected to the optocoupler chip 122, and the other end is connected to the first switch Q1 and the second switch Q2.

[0059] In this embodiment, the DSP (Digital Signal Processor) chip on the system controller sends a drive pulse signal to the optocoupler isolation module 120. The optocoupler isolation module 120 converts the drive pulse signal into an isolated drive signal to drive the first switch Q1 and the second switch Q2.

[0060] In some embodiments, the optocoupler input unit 121 may include a twelfth resistor R12, a fourth capacitor C4, and a fourth diode D4. One end of the twelfth resistor R12 is connected to the system controller, and the other end of the twelfth resistor R12 is connected to the Anode pin of the optocoupler chip 122, forming a fifth node N5; one end of the fourth capacitor C4 is connected to the fifth node N5, and the other end of the fourth capacitor C4 is grounded; the cathode of the fourth diode D4 is connected to the Anode pin of the optocoupler chip 122, and the anode of the fourth diode D4 is connected to the cathode pin of the optocoupler chip 122 and grounded.

[0061] The optocoupler output unit 123 may include a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, an eighth capacitor C8, a fifth diode D5, a thirteenth resistor R13, a first polarity capacitor C9, and a second polarity capacitor C10. The power supply pin Vcc of the optocoupler chip 122 is connected to an external power supply, and the ground pin (GND) of the optocoupler chip 122 is grounded. The fifth capacitor C5 is connected in parallel between the power supply pin Vcc and the ground pin of the optocoupler chip 122, and the sixth capacitor C6 is connected in parallel between the power supply pin Vcc and the ground pin of the optocoupler chip 122. The cathode of the fifth diode D5 is connected to one end of the sixth capacitor C6, forming a sixth node N6. The anode of the fifth diode D5 is connected to the output pin (Vo) of the optocoupler chip 122, forming a seventh node N7. One end of the seventh capacitor C7 is connected to the sixth node N6, and the other end of the seventh capacitor C7 is connected to the seventh node N7. One end of the first polarity capacitor C9 is connected to the sixth node N6, and the other end of the first polarity capacitor C9 is connected to the seventh node N7.

[0062] One end of the thirteenth resistor R13 is connected to the other end of the sixth capacitor C6, forming the eighth node N8. The other end of the thirteenth resistor R13 is connected to the output pin of the optocoupler chip 122, forming the ninth node N9. One end of the eighth capacitor C8 is connected to the eighth node N8, and the other end of the eighth capacitor C8 is connected to the ninth node N9. One end of the second polarity capacitor C10 is connected to the eighth node N8, and the other end of the second polarity capacitor C10 is connected to the ninth node N9.

[0063] In this embodiment, the optocoupler chip 122 can be a TLP57 series optocoupler chip 122. For example... Figure 5 As shown, the Anode pin of optocoupler chip 122 can be connected to the system controller to receive the drive pulse signal output by the system controller. The twelfth resistor R12 is a current-limiting resistor used to limit the current magnitude. The cathode pin of optocoupler chip 122 is grounded. A fourth capacitor C4 is connected in parallel between the cathode pin and the Anode pin of optocoupler chip 122. Furthermore, a fourth diode D4 is also connected in parallel between the cathode pin and the Anode pin of optocoupler chip 122. The fourth capacitor C4 is a filter capacitor used for filtering, and the fourth diode D4 is a reverse protection diode used to prevent reverse current flow.

[0064] The Vcc pin of optocoupler chip 122 is connected to an external 15V DC power supply, and its ground pin is connected to 15V ground. A fifth capacitor C5 and a sixth capacitor C6 are connected in parallel between the Vcc and ground pins of the optocoupler chip; these capacitors are used for filtering. A fifth diode D5 is connected in parallel between the Vcc and Vo pins of optocoupler chip 122; this diode is a 12V Zener diode, which clamps the entire 15V DC current into a 12V output and a 3V output. A thirteenth resistor R13 is used for current limiting, and both the seventh capacitor C7 and the eighth capacitor C8 are used for loop filtering. Finally, the Vo pin of optocoupler isolation module 120 can output positive 12V and negative 3V pulses to drive the first switch Q1 and the second switch Q2.

[0065] Therefore, this embodiment, through the push-pull converter module 110 combined with a series pulse transformer Tx topology, not only achieves higher conversion efficiency than common topologies, but also significantly enhances driving capability through the primary-side series transformer design, while reducing the number of components required for the isolation circuit, thereby effectively reducing system cost. Secondly, this design fully utilizes the characteristic that a thyristor only needs the first pulse to reach a strong trigger current to conduct, distinguishing the two current outputs of the push-pull converter module 110 into a leading large pulse current and a subsequent small pulse current. This differentiated output strategy significantly reduces the overall output power of the push-pull converter module 110, allowing for optimization in size and cost. Finally, the pulse transformer Tx adopts a planar flat PCB transformer process, greatly compressing the physical space occupied by the trigger circuit, saving valuable space for the overall structural layout, and further reducing costs.

[0066] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A trigger circuit for a thyristor, characterized in that, It includes a push-pull converter module, an optocoupler isolation module, and a power supply module, wherein the push-pull converter module includes at least one pulse transformer; The primary winding of each pulse transformer is connected to the power supply module and the optocoupler isolation module, respectively, and the secondary winding of each pulse transformer is connected to a thyristor.

2. The thyristor triggering circuit according to claim 1, characterized in that, The pulse transformer includes a first primary coil and a second primary coil, wherein the first primary coil and the second primary coil are connected in series. The push-pull converter module includes a switching unit, which includes a first switching transistor and a second switching transistor. One end of the first primary coil is connected to the first end of the first switching transistor, and the other end of the first primary coil is connected to the positive terminal of the power supply module. The second end of the first switching transistor is connected to the negative terminal of the power supply module. One end of the second primary coil is connected to the positive terminal of the power supply module, and the other end of the second primary coil is connected to the first end of the second switching transistor. The second end of the second switching transistor is connected to the negative terminal of the power supply module. The third ends of the first and second switching transistors are connected to the optocoupler isolation module.

3. The thyristor triggering circuit according to claim 2, characterized in that, The switching unit further includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first capacitor, and a second capacitor; One end of the first resistor is connected to the optocoupler isolation module, and the other end of the first resistor is connected to the third end of the first switch to form a first node; The second resistor is connected in series with the first capacitor and then connected in parallel between the first and second terminals of the first switching transistor. One end of the third resistor is connected to the optocoupler isolation module, and the other end of the third resistor is connected to the third end of the second switch to form a second node; The fourth resistor is connected in series with the second capacitor and then connected in parallel between the first and second terminals of the second switching transistor. One end of the fifth resistor is connected to the first node, and the other end of the fifth resistor is connected to the first end of the first switch to form a third node, which is grounded. One end of the sixth resistor is connected to the second node, and the other end of the sixth resistor is connected to the first end of the second switch to form a fourth node, which is grounded.

4. The trigger circuit for the thyristor according to any one of claims 1 to 3, characterized in that, The push-pull converter module includes at least one rectifier output unit; One end of each of the rectifier output units is connected to the secondary coil of a pulse transformer, and the other end of each of the rectifier output units is connected to a thyristor.

5. The trigger circuit for the thyristor according to claim 4, characterized in that, The pulse transformer includes a first secondary coil and a second secondary coil, which are connected in series. The rectifier output unit includes a first diode, a second diode, a first resistor subunit, and a second resistor subunit, wherein the resistance value of the first resistor subunit is less than the resistance value of the second resistor subunit. The anode of the first diode is connected to one end of the first secondary coil, the cathode of the first diode is connected to one end of the first resistor sub-unit, and the other end of the first resistor sub-unit is connected to the gate of the corresponding thyristor. The anode of the second diode is connected to one end of the second secondary coil, the cathode of the second diode is connected to one end of the second resistor subunit, and the other end of the second resistor subunit is connected to the gate of the corresponding thyristor. The other end of the first secondary coil and the other end of the second secondary coil are connected in series and then connected to the cathode of the corresponding thyristor.

6. The trigger circuit for the thyristor according to claim 5, characterized in that, The rectifier output unit also includes a seventh resistor, a third capacitor, and a third diode; One end of the seventh resistor is connected to the gate of the corresponding thyristor, and the other end of the seventh resistor is connected to the cathode of the corresponding thyristor. One end of the third capacitor is connected to the gate of the corresponding thyristor, and the other end of the third capacitor is connected to the cathode of the corresponding thyristor. The cathode of the third diode is connected to the gate of the corresponding thyristor, and the anode of the third diode is connected to the cathode of the corresponding thyristor.

7. The thyristor triggering circuit according to claim 5, characterized in that, The first resistor subunit includes an eighth resistor, a ninth resistor, and a tenth resistor, and the second resistor subunit includes an eleventh resistor; The eighth resistor, the ninth resistor, and the tenth resistor are connected in parallel. One end of the connection is connected to the cathode of the first diode, and the other end is connected to the gate of the corresponding thyristor. One end of the eleventh resistor is connected to the cathode of the second diode, and the other end of the eleventh resistor is connected to the gate of the corresponding thyristor.

8. The trigger circuit for the thyristor according to claim 2, characterized in that, The optocoupler isolation module includes an optocoupler chip, an optocoupler input unit, and an optocoupler output unit; One end of the optocoupler input unit is connected to the system controller, and the other end of the optocoupler input unit is connected to the optocoupler chip; One end of the optocoupler output unit is connected to the optocoupler chip, and the other end of the optocoupler output unit is connected to the first switch and the second switch.

9. The trigger circuit for the thyristor according to claim 8, characterized in that, The optocoupler input unit includes a twelfth resistor, a fourth capacitor, and a fourth diode; One end of the twelfth resistor is connected to the system controller, and the other end of the twelfth resistor is connected to the Anode pin of the optocoupler chip, forming the fourth node; One end of the fourth capacitor is connected to the fourth node, and the other end of the fourth capacitor is grounded. The cathode of the fourth diode is connected to the Anode pin of the optocoupler chip, and the anode of the fourth diode is connected to the cathode pin of the optocoupler chip and grounded.

10. The trigger circuit for the thyristor according to claim 8, characterized in that, The optocoupler output unit includes a fifth capacitor, a sixth capacitor, a seventh capacitor, an eighth capacitor, a fifth diode, a thirteenth resistor, a first polarity capacitor, and a second polarity capacitor. The power supply pin of the optocoupler chip is connected to an external power supply, and the ground pin of the optocoupler chip is grounded. The fifth capacitor is connected in parallel between the power supply pin and the ground pin of the optocoupler chip, and the sixth capacitor is connected in parallel between the power supply pin and the ground pin of the optocoupler chip. The cathode of the fifth diode is connected to one end of the sixth capacitor to form a fifth node. The anode of the fifth diode is connected to the output pin of the optocoupler chip to form a sixth node. One end of the seventh capacitor is connected to the fifth node, and the other end of the seventh capacitor is connected to the sixth node. One end of the first polarized capacitor is connected to the fifth node, and the other end of the first polarized capacitor is connected to the sixth node. One end of the thirteenth resistor is connected to the other end of the sixth capacitor to form a seventh node. The other end of the thirteenth resistor is connected to the output pin of the optocoupler chip to form an eighth node. One end of the eighth capacitor is connected to the seventh node, and the other end of the eighth capacitor is connected to the eighth node. One end of the second polarity capacitor is connected to the seventh node, and the other end of the second polarity capacitor is connected to the eighth node.

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