A short-circuit protection device for inverter bridge in medium frequency power supply equipment

Abstract

The present invention proposes an inverter bridge short-circuit protection device in a medium-frequency power supply device, comprising: a monitoring module, an execution module and a prompting module; the input end of the monitoring module is connected to the output end of the three-phase rectifier bridge arm system, and the monitoring module is used to detect whether the input voltage of the medium-frequency inverter bridge is damaged and short-circuited; the execution module comprises: a first controllable switch unit, a second controllable switch unit and an inverter thyristor triggering module, the control end of the first controllable switch unit is connected to the output end of the monitoring module, and the second controllable switch unit has a first control switch and a first execution switch; the prompting module is connected in parallel with the first control switch, and the prompting module is used to prompt that the first control switch has been connected to the first power supply voltage. The inverter bridge short-circuit protection device in the medium-frequency power supply device solves the problem that the thyristor in the medium-frequency inverter bridge in the prior art has no secondary protection.

Description

Technical Field

[0001] The invention relates to power supply equipment, in particular to an inverter bridge short-circuit protection device in a medium-frequency power supply equipment. Background Art

[0002] The medium frequency power supply equipment includes: medium frequency inverter bridge and three-phase rectifier bridge arm system.

[0003] The medium frequency inverter bridge includes: an inverter thyristor module KA, an inverter thyristor module KB, a resistor RJ1, a resistor RJ2, a capacitor C1, a capacitor C2, an inductor LA, an inductor LB and an inductor L. One end of the inductor LA is CD+ of the medium frequency inverter bridge, the input end of the inverter thyristor module KA is connected to the other end of the inductor LA, the output end of the inverter thyristor module KA is connected to the input end of the inverter thyristor module KB, the connection point between the output end of the inverter thyristor module KA and the input end of the inverter thyristor module KB is the inverter output end X, the output end of the inverter thyristor module KB is connected to one end of the inductor LB, and the other end of the inductor LB is the medium frequency inverter bridge CD-. One end of the resistor RJ1 is connected to the positive electrode CD+ of the power supply, the other end of the resistor RJ1 is connected to one end of the resistor RJ2 and connected to the inverter output end X, and the other end of the resistor RJ2 is connected to the medium frequency inverter bridge CD-. The positive electrode of capacitor C1 is connected to the intermediate frequency inverter bridge CD+, the negative electrode of capacitor C1 is connected to the positive electrode of capacitor C2, the junction of capacitor C1 and capacitor C2 is connected to the inverter output terminal X through the inductor L, and the negative electrode of capacitor C2 is connected to the intermediate frequency inverter bridge CD-.

[0004] Although the above can realize the function of the medium frequency inverter bridge, the medium frequency inverter bridge still has the following problems: the protection of the thyristor of the traditional medium frequency inverter bridge mostly adopts the RC absorption circuit to protect the thyristor. When the thyristor of the inverter bridge is damaged, there is no secondary protection. It will start again before the fault is eliminated, burning more thyristors or circuit breakers. Summary of the invention

[0005] The present invention aims to provide an inverter bridge short-circuit protection device in a medium frequency power supply device, so as to solve the problem that the thyristor in the medium frequency inverter bridge in the prior art has no secondary protection.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] The invention proposes an inverter bridge short-circuit protection device in a medium frequency power supply device, comprising: a monitoring module, an execution module and a prompting module; the input end of the monitoring module is connected to CD+, CD- and a common end of the medium frequency inverter bridge, and the monitoring module is used to detect whether the input voltage of the medium frequency inverter bridge is damaged and short-circuited; the execution module comprises: a first controllable switch unit, a second controllable switch unit, a medium frequency control main board and an inverter thyristor triggering module, the control end of the first controllable switch unit is connected to the output end of the monitoring module, the second controllable switch unit has a first control switch and a first execution switch, the first control switch is used to control the first execution switch to be closed when the loop where the first control switch is located is connected, and to control the first execution switch to be closed when the loop where the first control switch is located is disconnected, one end of the first control switch is connected to a first power supply voltage, the other end of the first control switch of the second controllable switch unit is grounded through the first controllable switch unit, the second power supply voltage is connected to the input end of the medium frequency control main board through the first execution switch in the second controllable switch unit, and the output end of the medium frequency control main board is connected to the inverter thyristor triggering module; the prompting module is connected in parallel with the first control switch, and the prompting module is used to prompt that the first control switch has been connected to the first power supply voltage.

[0008] Preferably, the first controllable switch unit is a switching transistor.

[0009] Preferably, the second controllable switch is a relay.

[0010] Preferably, the prompt module includes: a prompt light.

[0011] Preferably, a first connecting part is provided on the warning light, a second connecting part is provided on the relay, the monitoring module and the first controllable switch unit are installed on a circuit board, and a connecting component for electrically connecting the first connecting part and the second connecting part is installed on the circuit board.

[0012] Preferably, the connecting component includes: an electrical connecting column, a first spring sheet, a second spring sheet and a detachment limiting mechanism, the electrical connecting column is installed on the circuit board, the first spring sheet and the second spring sheet are formed on the electrical connecting column, the first spring sheet is used to electrically connect to the first connecting part, the second spring sheet is used to electrically connect to the second connecting part, and the detachment limiting mechanism is used to limit the first spring sheet from detaching from the first connecting part, and limit the second spring sheet from detaching from the second connecting part.

[0013] Preferably, the electrical connection post is fixed to the mounting post, and the release limiting mechanism acts on the mounting post.

[0014] Preferably, an obstruction member is provided between the first connecting portion and the first elastic sheet, and the obstruction member is used to allow the obstruction mechanism to cooperate with the mounting column only after the first connecting portion and the first elastic sheet clamp the obstruction member.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The inverter thyristor of the new series medium-frequency inverter bridge is controlled when it is damaged and short-circuited. When the inverter thyristor is damaged and short-circuited, the inverter pulse and input voltage of the medium-frequency inverter bridge are disconnected, and the equipment cannot be started again before the fault is restored, thereby protecting the medium-frequency inverter bridge, avoiding more damage to the thyristor and extending the service life; at the same time, when the monitoring module controls the inverter thyristor trigger module to disconnect, it also controls the disconnection; subsequently, the medium-frequency control mainboard and the inverter thyristor trigger module are designed to control the thyristor in the inverter bridge and avoid the situation where the circuit breaker cannot be used for control. Since the circuit breaker can only realize the on and off of the power supply, it cannot realize the buffering pulse of sudden power failure, and the use of the thyristor trigger module can effectively buffer the pulse, thereby improving the protection effect; finally, the rectifier thyristor trigger module is added to control the thyristor in the three-phase rectifier circuit, thereby realizing joint protection, making the service life reliability of the entire system higher.

[0017] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is the circuit block diagram of the inverter bridge short-circuit protection device in the medium frequency power supply equipment;

[0019] Figure 2 is a cross-sectional view of a circuit board;

[0020] Figure 3 This is the circuit diagram of the monitoring module;

[0021] Figure 4 This is the circuit diagram of the medium frequency inverter bridge.

[0022] Figure numerals: warning light 1, first connecting part 2, blocking member 20, stop rod 21, second connecting part 3, circuit board 4, connecting assembly 5, electrical connecting column 51, first spring piece 52, second spring piece 53, stop mechanism 54, mounting column 55, screw 56. DETAILED DESCRIPTION

[0023] In order to make the technical means, creative features, objectives and functions of the present invention clearer and easier to understand, the present invention is further described below in conjunction with the accompanying drawings and specific embodiments:

[0024] like Figures 1 to 4As shown, the present invention proposes an inverter bridge short-circuit protection device in a medium frequency power supply device, including: a monitoring module, an execution module and a prompt module; the input end of the monitoring module is connected to the CD+, CD- and common ends of the medium frequency inverter bridge, and the monitoring module is used to detect whether the input voltage of the medium frequency inverter bridge is damaged and short-circuited; the execution module includes: a first controllable switch unit, a second controllable switch unit, a medium frequency control main board and an inverter thyristor trigger module, the control end of the first controllable switch unit is connected to the output end of the monitoring module, the second controllable switch unit has a first control switch and a first execution switch, and the first control switch is used When the loop where the first control switch is located is connected, the first execution switch is controlled to be closed, and when the loop where the first control switch is located is disconnected, the first execution switch is controlled to be closed, one end of the first control switch is connected to the first power supply voltage, the other end of the first control switch of the second controllable switch unit is grounded through the first controllable switch unit, the second power supply voltage is connected to the input end of the intermediate frequency control mainboard through the first execution switch in the second controllable switch unit, and the output end of the intermediate frequency control mainboard is connected to the inverter thyristor trigger module; the prompt module is connected in parallel with the first control switch, and the prompt module is used to prompt that the first control switch has been connected to the first power supply voltage.

[0025] The inverter thyristor trigger module includes: two thyristor trigger transformers, the input ends of the two thyristor trigger transformers are connected to the medium frequency control mainboard, and each thyristor trigger transformer is connected to the control end of a thyristor in the medium frequency inverter bridge, so as to control the thyristor to disconnect and protect the thyristor when overvoltage occurs. The two thyristors in the medium frequency inverter bridge are each provided with a thyristor trigger transformer.

[0026] The execution module also includes: a rectifier thyristor trigger module, through which the intermediate frequency control main board is connected to each thyristor in the three-phase rectifier bridge arm system. The rectifier thyristor trigger module includes: 6 thyristor trigger transformers, the input ends of the 6 thyristor trigger transformers are all connected to the intermediate frequency control main board, and each thyristor trigger transformer is connected to the control end of a thyristor in the three-phase rectifier bridge arm system, so as to control all thyristors in the three-phase rectifier bridge arm system and the intermediate frequency inverter bridge to be disconnected when overvoltage occurs, thereby protecting all thyristors, and thyristor trigger transformers are correspondingly set for the 6 thyristors in the intermediate frequency inverter bridge.

[0027] The first controllable switch unit is a switch transistor.

[0028] The second controllable switch is a relay, and has multiple groups of switches inside.

[0029] The prompt module includes: a prompt light 1.

[0030] In order to realize the parallel connection of the warning light 1 and the relay, the warning light 1 is provided with a first connection part 2, the relay is provided with a second connection part 3, the monitoring module and the first controllable switch unit are mounted on a circuit board 4, and a connection component 5 for electrically connecting the first connection part 2 and the second connection part 3 is mounted on the circuit board 4. There are two first connection parts 2, two second connection parts 3 and two connection components 5, so as to realize the electrical connection at both ends.

[0031] In order to design a connection component 5 with a simple structure, the connection component 5 includes: an electrical connection column 51, a first spring clip 52, a second spring clip 53 and a limiting mechanism 54. The electrical connection column 51 is installed on the circuit board 4. The first spring clip 52 and the second spring clip 53 are formed on the electrical connection column 51. The first spring clip 52 is used to electrically connect to the first connection part 2, and the second spring clip 53 is used to electrically connect to the second connection part 3. The limiting mechanism 54 is used to limit the first spring clip 52 from being separated from the first connection part 2, and to limit the second spring clip 53 from being separated from the second connection part 3.

[0032] In order to provide an installation basis for the limiting mechanism 54 , the electrical connection column 51 is fixed to the installation column 55 , and the limiting mechanism 54 acts on the installation column 55 .

[0033] In order to avoid forgetting to install the warning light 1 before installing the relay, a blocking member 20 is provided between the first connecting portion 2 and the first elastic sheet 52 . The blocking member 20 is used to allow the blocking mechanism to cooperate with the mounting column 55 only after the first connecting portion 2 and the first elastic sheet 52 clamp the blocking member 20 .

[0034] The first connection part 2 is an L-shaped structure, and one end of the first connection part 2 is used to be inserted into the mounting hole opened by the mounting column 55. The first spring piece 52 is located in the mounting hole, and the first connection part 2 is snap-fitted with the inner wall of the mounting hole. In order to prevent the first connection part 2 from detaching, ensure the stability of the connection, and avoid the possibility of the first connection part 2 detaching from the mounting column 55, a limited disengagement rod 21 is protruded on the first connection part 2, and the outer wall of the mounting column 55 is recessed to form a receiving groove, and the limited disengagement rod 21 is placed in the receiving groove.

[0035] One end of the second connection portion 3 is a circular ring structure, and the second connection portion 3 is sleeved outside the mounting column 55 .

[0036] The limiting mechanism 54 includes a nut. A screw 56 is formed on the top of the mounting column 55. The screw 56 is threadedly connected to the nut. The nut is used to press the second connecting part 3 onto the first connecting part 2 so that the second connecting part 3 is in close contact with the second elastic sheet 53.

[0037] The first elastic sheet 52 , the second elastic sheet 53 , the first connecting portion 2 , the second connecting portion 3 and the blocking member 20 are all made of elastic rubber.

[0038] The bottom of the nut is provided with an annular groove for one end of the blocking member 20 to extend into. When the first connecting portion 2 and the first elastic sheet 52 are not clamped with the blocking member 20, the nut cannot be aligned with both the screw rod 56 and the annular groove. When the first connecting portion 2 and the first elastic sheet 52 are clamped with the blocking member 20, the nut can be aligned with both the screw rod 56 and the annular groove.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. An inverter bridge short-circuit protection device in a medium frequency power supply device, characterized in that: include: Monitoring module, execution module and prompt module; The input end of the monitoring module is connected to CD+, CD- and the common end of the intermediate frequency inverter bridge. The monitoring module is used to detect whether the input voltage of the intermediate frequency inverter bridge is damaged or short-circuited; The execution module includes: a first controllable switch unit, a second controllable switch unit, an intermediate frequency control mainboard and an inverter thyristor trigger module, wherein the control end of the first controllable switch unit is connected to the output end of the monitoring module, the second controllable switch unit has a first control switch and a first execution switch, the first control switch is used to control the first execution switch to be closed when the loop where the first control switch is located is connected, and to control the first execution switch to be closed when the loop where the first control switch is located is disconnected, one end of the first control switch is connected to the first power supply voltage, the other end of the first control switch of the second controllable switch unit is grounded through the first controllable switch unit, the second power supply voltage is connected to the input end of the intermediate frequency control mainboard through the first execution switch in the second controllable switch unit, and the output end of the intermediate frequency control mainboard is connected to the inverter thyristor trigger module; The prompt module is connected in parallel with the first control switch, and is used to prompt that the first control switch has been connected to the first power supply voltage; The prompt module includes: a prompt light; The warning light is provided with a first connection part, the relay is provided with a second connection part, the monitoring module and the first controllable switch unit are mounted on a circuit board, and a connection component for electrically connecting the first connection part and the second connection part is mounted on the circuit board; The connection assembly includes: an electrical connection column, a first spring sheet, a second spring sheet, and a detachment limiting mechanism, wherein the electrical connection column is mounted on a circuit board, and the first spring sheet and the second spring sheet are formed on the electrical connection column, wherein the first spring sheet is used to be electrically connected to the first connection portion, and the second spring sheet is used to be electrically connected to the second connection portion, and the detachment limiting mechanism is used to limit the detachment of the first spring sheet from the first connection portion, and limit the detachment of the second spring sheet from the second connection portion; The electrical connection column is fixed to the mounting column, and the release limiting mechanism is in contact with the mounting column; An obstruction member is provided between the first connection portion and the first elastic sheet, and the obstruction member is used to allow the obstruction mechanism to cooperate with the mounting column only after the first connection portion and the first elastic sheet clamp the obstruction member; The first connecting part is an L-shaped structure, one end of the first connecting part is used to be inserted into the mounting hole provided in the mounting column, the first elastic sheet is located in the mounting hole, and the first connecting part is snap-fitted with the inner wall of the mounting hole; One end of the second connecting part is a circular ring structure, and the second connecting part is sleeved outside the mounting column; The limiting mechanism includes: a nut, a screw is formed on the top of the mounting column, the screw is threadedly connected with the nut, and the nut is used to press the second connection part onto the first connection part, so that the second connection part is in close contact with the second elastic sheet; The first spring sheet, the second spring sheet, the first connecting portion, the second connecting portion and the blocking member are all made of elastic rubber; An annular groove is provided at the bottom of the nut for one end of the blocking member to extend into. When the first connecting portion and the first spring sheet are not clamped with the blocking member, the nut cannot be aligned with both the screw rod and the annular groove; when the first connecting portion and the first spring sheet are clamped with the blocking member, the nut can be aligned with both the screw rod and the annular groove.

2. The inverter bridge short-circuit protection device in a medium frequency power supply device according to claim 1, characterized in that: The first controllable switch unit is a switch transistor.

3. The inverter bridge short-circuit protection device in a medium frequency power supply device according to claim 1, characterized in that: The second controllable switch is a relay.

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