Soft starter with voltage regulator self-inspection function

Abstract

The utility model discloses a soft starter with a voltage regulator self-inspection function, which performs static detection and trigger detection on a thyristor before being put into use, eliminates the existing potential problems of the thyristor before equipment is put into operation, and prevents the whole motor system from being influenced by faults of the soft starter in the operation process. Production interruption or power grid impact can be effectively prevented; and meanwhile, the detection core circuit is reused, and the state detection of a plurality of groups of anti-parallel thyristors can be realized only by arranging one set of detection circuit, so that the hardware cost of the soft starter is greatly reduced. According to the technical scheme, the soft starter with the self-checking function of the voltage regulator multiplexes the drive circuit through the channel selection switch, and realizes the self-checking function of the thyristor with industrial-grade reliability under the condition of limited hardware cost.

Description

Technical Field

[0001] This utility model relates to the field of soft starter technology, specifically to a soft starter with self-testing of voltage regulating device. Background Technology

[0002] A soft starter is an advanced motor control device that integrates motor soft starting, soft stopping, light-load energy saving, and multiple protection functions. Its core function is to gradually adjust the input voltage through anti-parallel thyristors to achieve smooth motor starting, stopping, and operation protection.

[0003] Anti-parallel thyristors are key components of soft starters. Their failure can prevent motors from starting properly, causing production interruptions. Furthermore, a short circuit in the thyristor can lead to uncontrolled starting current, threatening grid stability. From a safety perspective, the most detrimental aspect of power equipment is hidden faults, especially in applications requiring high system reliability, safety, and ease of maintenance. If the anti-parallel thyristor fails during motor startup and operation, it can easily prevent the motor from operating normally, leading to production interruptions or even accidents. Soft starters typically use three sets of anti-parallel thyristors for motor control, and configuring corresponding detection circuits for each set would significantly increase production costs.

[0004] In view of this, there is an urgent need to design a soft starter with self-testing function of voltage regulating device and low cost. Summary of the Invention

[0005] To address the aforementioned issues, this utility model provides a soft starter with self-testing of voltage regulating devices, comprising a processor, a thyristor drive circuit, and an anti-parallel thyristor group. The output terminal of the processor is connected to the input terminal of the thyristor drive circuit, and the output terminal of the thyristor drive circuit is connected to the anti-parallel thyristor group. It also includes a channel selection circuit, a detection trigger circuit, an isolation test power supply, a thyristor detection switch circuit, and a thyristor voltage detection circuit.

[0006] The processor's output terminal is connected to the input terminal of the channel selection circuit and the detection trigger circuit, respectively. The output terminal of the detection trigger circuit is connected to the input terminal of the channel selection circuit. The output terminal of the channel selection circuit is connected to the gate of each thyristor in the anti-parallel thyristor group, respectively. The processor independently controls the gate drive of each thyristor in the anti-parallel thyristor group through the channel selection circuit and the detection trigger circuit.

[0007] The isolation test power supply and the thyristor detection switch circuit are respectively connected to the anti-parallel thyristor group, and the isolation test power supply provides test voltage to the anti-parallel thyristor group;

[0008] The thyristor detection switch circuit is connected to the input terminal of the thyristor voltage detection circuit, and the output terminal of the thyristor voltage detection circuit is connected to the input terminal of the processor. The thyristor detection switch circuit is used to switch the connection between the anti-parallel thyristor group and the thyristor voltage detection circuit.

[0009] This technical solution includes a soft starter with self-testing of voltage regulating devices, comprising thyristor static detection and thyristor trigger detection.

[0010] The working principle of thyristor trigger detection is as follows: Before the soft starter is put into operation, a pre-test is performed. The processor drives the detection trigger circuit to output the gate drive signal of the control thyristor. At the same time, the control channel selection circuit enables the detection trigger circuit to sequentially trigger the gates of the thyristors in the anti-parallel thyristor group. The isolation test power supply applies a constant current to the thyristor. The thyristor voltage detection circuit detects the current voltage value of the thyristor and determines whether the thyristor triggering is normal based on the voltage value.

[0011] The working principle of thyristor static testing is as follows: without applying a trigger signal to the thyristor gate, the isolated test power supply directly applies a constant current power supply to the thyristor, the thyristor voltage detection circuit detects the current voltage value of the thyristor, and determines whether the thyristor is blocking normally based on the voltage value.

[0012] This technical solution features a soft starter with self-testing of voltage regulating devices. Before commissioning, it performs static and trigger tests on the thyristors, eliminating potential problems with the thyristors before the equipment is put into operation. This prevents the soft starter from malfunctioning during operation and affecting the entire motor system, effectively preventing production interruptions or grid impacts. At the same time, it reuses the core detection circuit, requiring only one detection circuit to realize the status detection of multiple anti-parallel thyristor groups, significantly reducing the hardware cost of the soft starter.

[0013] This technical solution, a soft starter with self-testing of voltage regulating devices, achieves industrial-grade reliability thyristor self-testing function through channel selection switch multiplexing drive circuit with almost no increase in hardware cost. It is especially suitable for small and medium power soft starters that require strict cost control. Attached Figure Description

[0014] Figure 1 This is a block diagram of a soft starter circuit with self-testing voltage regulating device according to an embodiment of the present invention.

[0015] Figure 2 This is a schematic diagram of the detection trigger circuit in an embodiment of the present invention.

[0016] Figure 3 This is a schematic diagram of the channel selection circuit in an embodiment of the present invention.

[0017] Figure 4 This is a schematic diagram of the isolation test power supply circuit according to an embodiment of the present invention.

[0018] Figure 5 This is a schematic diagram of the anti-parallel thyristor group circuit according to an embodiment of the present invention.

[0019] Figure 6 This is a schematic diagram of the thyristor detection switch circuit and part of the thyristor voltage detection circuit in an embodiment of this utility model.

[0020] Figure 7 This is a schematic diagram of a thyristor voltage detection circuit in an embodiment of this utility model. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0022] Combined with appendix Figure 1 To be continued Figure 7 The present invention is a soft starter with self-testing of voltage regulating device, including processor 1, thyristor drive circuit 2 and anti-parallel thyristor group 3. The output terminal of processor 1 is connected to the input terminal of thyristor drive circuit 2, and the output terminal of thyristor drive circuit 2 is connected to the anti-parallel thyristor group 3. It also includes channel selection circuit 4, detection trigger circuit 5, isolation test power supply 6, thyristor detection switch circuit 7 and thyristor voltage detection circuit 8.

[0023] The output terminal of the processor 1 is connected to the input terminal of the channel selection circuit 4 and the detection trigger circuit 5 respectively. The output terminal of the detection trigger circuit 5 is connected to the input terminal of the channel selection circuit 4. The output terminal of the channel selection circuit 4 is connected to the gate of each thyristor in the anti-parallel thyristor group 3 respectively. The processor 1 independently controls the gate drive of each thyristor in the anti-parallel thyristor group 3 through the channel selection circuit 4 and the detection trigger circuit 5.

[0024] The isolation test power supply 6 and the thyristor detection switch circuit 7 are respectively connected to the anti-parallel thyristor group 3, and the isolation test power supply 6 provides test voltage to the anti-parallel thyristor group 3;

[0025] The thyristor detection switch circuit 7 is connected to the input terminal of the thyristor voltage detection circuit 8, and the output terminal of the thyristor voltage detection circuit 8 is connected to the input terminal of the processor 1. The thyristor detection switch circuit 7 is used to switch the connection between the anti-parallel thyristor group 3 and the thyristor voltage detection circuit 8.

[0026] In this embodiment, the soft starter with voltage regulating device self-test includes thyristor static detection and thyristor trigger detection.

[0027] The working principle of thyristor trigger detection is as follows: Before the soft starter is put into operation, a pre-test is performed. The processor 1 drives the detection trigger circuit 5 to output the control thyristor gate drive signal, and at the same time controls the channel selection circuit 4 so that the detection trigger circuit 5 sequentially triggers the gates of the anti-parallel thyristor group 3. The isolation test power supply 6 applies a constant current power supply to the thyristor. The thyristor voltage detection circuit 8 detects the current voltage value of the thyristor and determines whether the thyristor triggering is normal based on the voltage value.

[0028] The working principle of static thyristor testing is as follows: without applying a trigger signal to the gate of the thyristor, the isolation test power supply 6 directly applies a constant current power supply to the thyristor, and the thyristor voltage detection circuit 8 detects the current voltage value of the thyristor and determines whether the thyristor is blocking normally based on the voltage value.

[0029] In this embodiment, after the thyristor self-test is completed, the processor 1 controls the thyristor detection switch circuit 7 to disconnect, so as to avoid the high voltage during the soft start process from affecting the thyristor voltage detection circuit 8.

[0030] In this embodiment, as shown in the appendix Figure 2 As shown, the detection trigger circuit 5 includes resistors R1, R2, and R3, a transistor Q1, an optocoupler U1, a capacitor C1, and a gate driver amplifier chip U2. One end of resistor R1 is connected to the output terminal of the processor 1, and the other end of resistor R1 is connected to the base of transistor Q1. The emitter of transistor Q1 is grounded, and the collector of transistor Q1 is connected to the negative terminal of optocoupler U1. The positive terminal of optocoupler U1 is connected to one end of resistor R2, and the other end of resistor R2 is connected to a high level. The collector of optocoupler U1... With the high-level connection, the emitter of the optocoupler U1 is connected to one end of the resistor R3, and the other end of the resistor R3 is connected to the second pin of the gate driver amplifier chip U2. The first, third, and eighth pins of the gate driver amplifier chip U2 are all connected to the high-level connection, the fourth and fifth pins of the gate driver amplifier chip U2 are grounded, the sixth and seventh pins of the gate driver amplifier chip U2 are both connected to one end of the capacitor C1, the other end of the capacitor C1 is grounded, and the seventh pin of the gate driver amplifier chip U2 outputs a trigger drive signal.

[0031] In this embodiment, the optocoupler U1 and the gate drive amplifier chip U2 are used to realize the gate triggering of the thyristors in the parallel thyristor group 3, thereby achieving high voltage isolation.

[0032] In this embodiment, as shown in the appendix Figure 3 As shown, the channel selection circuit 4 includes an analog switch chip U3, resistors R4, R5, R6, R7, R8, and R9. The first, fifteenth, and sixteenth pins of the analog switch chip U3 are connected to the output terminals of the processor 1, the third and fourteenth pins of the analog switch chip U3 are grounded, the thirteenth pin of the analog switch chip U3 is connected to a high level, and the eighth pin of the analog switch chip U3 is connected to the seventh pin of the gate drive amplifier chip U2. One end of resistors R4, R5, R6, R7, R8, and R9 are connected to the channel pins of the analog switch chip U3, and the other ends of resistors R4, R5, R6, R7, R8, and R9 are connected to the gates of each thyristor in the anti-parallel thyristor group 3.

[0033] In this embodiment, the gate driver amplifier chip U2 is model IXDD414, and the analog switch chip U3 is model DG408.

[0034] In this embodiment, the processor 1 triggers the analog switch chip U3 by sending signals to A0, A1, and A2, and selects channels S1-S6 to trigger in turn. In this embodiment, three sets of anti-parallel thyristors are detected, so an 8-channel analog switch chip is sufficient.

[0035] In this embodiment, as shown in the appendix Figure 4As shown, the isolation test power supply 6 includes resistors R10, R11, R12, R13, R14, and R15, capacitors C2 and C3, operational amplifier U4, and MOSFET Q2. One end of resistor R10 is connected to the output terminal of processor 1, and the other end of resistor R10 is connected to one end of resistor R11 and the non-inverting input terminal of operational amplifier U4. The other end of resistor R11 is grounded. Capacitor C2 is connected in parallel across resistor R11. The output of operational amplifier U4... The gate of the MOSFET Q2 is connected to the terminal of the resistor R14, the drain of the MOSFET Q2 is connected to one end of the resistor R14, the other end of the resistor R14 is connected to a high level, the capacitor C3 is connected in parallel across the two ends of the resistor R14, the source of the MOSFET Q2 is connected to one end of the resistor R13 and one end of the resistor R15, the other end of the resistor R15 is grounded, the other end of the resistor R13 is connected to the inverting input of the operational amplifier U4, and the source of the MOSFET Q2 outputs a constant current to each of the anti-parallel thyristor groups 3.

[0036] In this embodiment, as shown in the appendix Figure 5 and attached Figure 6 As shown, the thyristor detection switch circuit 7 includes a relay K1. One end of the first set of normally open contacts of the relay K1 is connected to the first end of the anti-parallel thyristor group 3, and one end of the second set of normally open contacts of the relay K1 is connected to the second end of the anti-parallel thyristor group 3. The coil of the relay K1 is connected to the output terminal of the processor 1. The processor 1 controls the coil of the relay K1 to be energized or de-energized via a drive signal.

[0037] In this embodiment, as shown in the appendix Figure 6 As shown, the thyristor voltage detection circuit 8 includes resistors R16, R17, R18, R19, and R20, and operational amplifier U5. One end of resistor R16 is connected to the other end of the first set of normally open contacts of relay K1, and the other end of resistor R16 is connected to the non-inverting input terminal of operational amplifier U5. One end of resistor R17 is connected to the other end of the second set of normally open contacts of relay K1, and the other end of resistor R17 is connected to the inverting input terminal of operational amplifier U5. One end of resistor R18 is connected to the inverting input terminal of operational amplifier U5, and the other end of resistor R18 is connected to the output terminal of operational amplifier U5 and one end of resistor R20.

[0038] In this embodiment, as shown in the appendix Figure 7As shown, the thyristor voltage detection circuit 8 also includes an isolation amplifier U6. The first and eighth pins of the isolation amplifier U6 are connected to a high level, the fourth and fifth pins of the isolation amplifier U6 are grounded, the second and third pins of the isolation amplifier U6 are connected to the output signal of the operational amplifier U5, and the sixth and seventh pins of the isolation amplifier U6 are connected to the input terminal of the processor 1.

[0039] In this embodiment, the isolation amplifier U6 is model AMC1301.

[0040] In this embodiment, a differential amplifier is used to collect the voltage difference between the anode and cathode of the thyristor in both static and triggered states to determine if there is a problem with the thyristor. Static detection.

[0041] In this embodiment, the processor 1 executes the logic for determining whether the thyristor is healthy:

[0042] Static detection: No detection pulse is sent, and the thyristor detection voltage Vak is obtained; if the thyristor detection voltage Vak is less than V_short_threshold (e.g., 0.5V), the thyristor is determined to be short-circuited.

[0043] Trigger detection: A detection pulse is sent, and the thyristor detection voltage Vak is read after a short delay during or after the pulse duration. If the thyristor detection voltage Vak is greater than V_open_threshold (e.g., 0.8 times the isolation test voltage), the thyristor is determined to be open-circuited / trigger failure. If the thyristor detection voltage Vak is less than V_open_threshold but greater than V_aging_threshold (e.g., 3V), the thyristor is determined to be aged / poor contact. If the thyristor detection voltage Vak is less than V_aging_threshold, the thyristor is determined to be conducting normally.

[0044] In this embodiment, an indicator circuit 9 is also included. The input terminal of the indicator circuit 9 is connected to the output terminal of the processor 1. If a problem is found in the thyristor after self-test, a warning light will be issued.

[0045] This technical solution features a soft starter with self-testing of voltage regulating devices. Before commissioning, it performs static and trigger tests on the thyristors, eliminating potential problems with the thyristors before the equipment is put into operation. This prevents the soft starter from malfunctioning during operation and affecting the entire motor system, effectively preventing production interruptions or grid impacts. At the same time, it reuses the core detection circuit, requiring only one detection circuit to realize the status detection of multiple anti-parallel thyristor groups, significantly reducing the hardware cost of the soft starter.

[0046] This technical solution, a soft starter with self-testing of voltage regulating devices, achieves industrial-grade reliability thyristor self-testing function through channel selection switch multiplexing drive circuit with almost no increase in hardware cost. It is especially suitable for small and medium power soft starters that require strict cost control.

[0047] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0048] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A soft starter with self-testing of voltage regulating device, comprising a processor, a thyristor drive circuit, and an anti-parallel thyristor group, wherein the output terminal of the processor is connected to the input terminal of the thyristor drive circuit, and the output terminal of the thyristor drive circuit is connected to the anti-parallel thyristor group, characterized in that, It also includes a channel selection circuit, a detection trigger circuit, an isolation test power supply, a thyristor detection switch circuit, and a thyristor voltage detection circuit; The processor's output terminal is connected to the input terminal of the channel selection circuit and the detection trigger circuit, respectively. The output terminal of the detection trigger circuit is connected to the input terminal of the channel selection circuit. The output terminal of the channel selection circuit is connected to the gate of each thyristor in the anti-parallel thyristor group, respectively. The processor independently controls the gate drive of each thyristor in the anti-parallel thyristor group through the channel selection circuit and the detection trigger circuit. The isolation test power supply and the thyristor detection switch circuit are respectively connected to the anti-parallel thyristor group, and the isolation test power supply provides test voltage to the anti-parallel thyristor group; The thyristor detection switch circuit is connected to the input terminal of the thyristor voltage detection circuit, and the output terminal of the thyristor voltage detection circuit is connected to the input terminal of the processor. The thyristor detection switch circuit is used to switch the connection between the anti-parallel thyristor group and the thyristor voltage detection circuit.

2. A soft starter with self-testing of voltage regulating device according to claim 1, characterized in that, The detection trigger circuit includes resistors R1, R2, and R3, a transistor Q1, an optocoupler U1, a capacitor C1, and a gate driver amplifier chip U2. One end of resistor R1 is connected to the output terminal of the processor, and the other end of resistor R1 is connected to the base of transistor Q1. The emitter of transistor Q1 is grounded, and the collector of transistor Q1 is connected to the negative terminal of optocoupler U1. The positive terminal of optocoupler U1 is connected to one end of resistor R2, and the other end of resistor R2 is connected to a high level. The collector of optocoupler U1 is connected to... When the signal is high, the emitter of the optocoupler U1 is connected to one end of the resistor R3, and the other end of the resistor R3 is connected to the second pin of the gate driver amplifier chip U2. The first, third, and eighth pins of the gate driver amplifier chip U2 are all connected to a high level. The fourth and fifth pins of the gate driver amplifier chip U2 are grounded. The sixth and seventh pins of the gate driver amplifier chip U2 are both connected to one end of the capacitor C1, and the other end of the capacitor C1 is grounded. The seventh pin of the gate driver amplifier chip U2 outputs a trigger drive signal.

3. A soft starter with self-testing of voltage regulating device according to claim 2, characterized in that, The channel selection circuit includes an analog switch chip U3, resistors R4, R5, R6, R7, R8, and R9. The first, fifteenth, and sixteenth pins of the analog switch chip U3 are connected to the output of the processor, the third and fourteenth pins are grounded, the thirteenth pin is connected to a high level, and the eighth pin is connected to the seventh pin of the gate driver amplifier chip U2. One end of each of the resistors R4, R5, R6, R7, R8, and R9 is connected to a channel pin of the analog switch chip U3. The other ends of each of the resistors R4, R5, R6, R7, R8, and R9 are connected to the gates of the thyristors in the anti-parallel thyristor group.

4. A soft starter with self-testing of voltage regulating device according to claim 3, characterized in that, The gate driver amplifier chip U2 is model IXDD414, and the analog switch chip U3 is model DG408.

5. A soft starter with self-testing of voltage regulating device according to claim 1, characterized in that, The isolation test power supply includes resistors R10, R11, R12, R13, R14, and R15, capacitors C2 and C3, operational amplifier U4, and MOSFET Q2. One end of resistor R10 is connected to the output of the processor, and the other end of resistor R10 is connected to one end of resistor R11 and the non-inverting input of operational amplifier U4. The other end of resistor R11 is grounded. Capacitor C2 is connected in parallel across resistor R11. The output of operational amplifier U4 is connected to... The gate of the MOSFET Q2 is connected to the resistor R14, the drain of the MOSFET Q2 is connected to one end of the resistor R14, the other end of the resistor R14 is connected to a high level, the capacitor C3 is connected in parallel across the resistor R14, the source of the MOSFET Q2 is connected to one end of the resistor R13 and one end of the resistor R15, the other end of the resistor R15 is grounded, the other end of the resistor R13 is connected to the inverting input of the operational amplifier U4, and the source of the MOSFET Q2 outputs a constant current to each of the anti-parallel thyristor groups.

6. A soft starter with self-testing of voltage regulating device according to claim 5, characterized in that, The thyristor detection switch circuit includes a relay K1. One end of the first set of normally open contacts of the relay K1 is connected to the first end of the anti-parallel thyristor group, and one end of the second set of normally open contacts of the relay K1 is connected to the second end of the anti-parallel thyristor group. The coil of the relay K1 is connected to the output terminal of the processor.

7. A soft starter with self-testing of voltage regulating device according to claim 6, characterized in that, The thyristor voltage detection circuit includes resistors R16, R17, R18, R19, and R20, and operational amplifier U5. One end of resistor R16 is connected to the other end of the first set of normally open contacts of relay K1, and the other end of resistor R16 is connected to the non-inverting input terminal of operational amplifier U5. One end of resistor R17 is connected to the other end of the second set of normally open contacts of relay K1, and the other end of resistor R17 is connected to the inverting input terminal of operational amplifier U5. One end of resistor R18 is connected to the inverting input terminal of operational amplifier U5, and the other end of resistor R18 is connected to the output terminal of operational amplifier U5 and one end of resistor R20.

8. A soft starter with self-testing of voltage regulating device according to claim 7, characterized in that, The thyristor voltage detection circuit also includes an isolation amplifier U6. The first and eighth pins of the isolation amplifier U6 are connected to a high level, the fourth and fifth pins of the isolation amplifier U6 are grounded, the second and third pins of the isolation amplifier U6 are connected to the output signal of the operational amplifier U5, and the sixth and seventh pins of the isolation amplifier U6 are connected to the input terminal of the processor.

9. A soft starter with self-testing of voltage regulating device according to claim 8, characterized in that, The isolation amplifier U6 is model AMC1301.

10. A soft starter with self-testing of voltage regulating device according to any one of claims 1 to 9, characterized in that, It also includes an indicator circuit, the input of which is connected to the output of the processor.

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