Valve unit and changeover valve system with fault protection function

Abstract

The present invention discloses a valve unit and a converter valve unit with a fault protection function, wherein the valve unit with a fault protection function includes: a bridge circuit, including at least two power components; a drive control module, connected to the control end of the power component; at least one clamping unit, the clamping unit is connected between the power component and the drive control module; at least one adjustment unit, connected to the clamping unit, and the adjustment unit can adjust the threshold of the clamping unit. When a fault occurs, the adjustment unit lowers the threshold of the clamping unit, so that the power component connected to the clamping unit is damaged and broken down to present a short-circuit state, and the valve unit is short-circuited by sacrificing the damaged power component, thereby avoiding further expansion of the fault impact. Under normal working conditions, the adjustment unit can increase the threshold of the clamping unit, which is beneficial to reducing the heat generated by the clamping unit, extending the practical life and reliability, and at the same time, it is also beneficial to improve the DC voltage utilization rate of the valve unit.

Description

Technical Field

[0001] The present invention relates to the field of flexible direct current power transmission, and in particular to a valve unit and a converter valve system with a fault protection function. Background Art

[0002] In the field of flexible direct current transmission, the converter valve is composed of multiple valve units cascaded in series. When a valve unit fails, the faulty valve unit is required to be in a short-circuit state to prevent the capacitor voltage in the faulty valve unit from being too high or the capacitor short-circuiting and discharging, causing danger, so that the remaining valve units can work normally.

[0003] When the converter valve is first started, if the valve unit power supply fails to work, the valve unit is a black module for the upper valve control system. The valve unit cannot trigger the bypass and is in a short-circuit state, which is bound to cause a greater fault. Or, when the valve unit fails, the bypass switch cannot operate due to mechanical failure or drive module failure, causing the valve unit to be in a short-circuit state, which is bound to cause a greater fault. Therefore, it is required that other methods can be used to make the valve unit short-circuit in the case of a black module or when the bypass switch cannot operate.

[0004] In the prior art, some converter valves are provided with a clamping circuit in the valve unit, and the clamping circuit is connected to the power device in the valve unit. In the event of a fault, the clamping circuit is broken down, causing the power device to conduct, and then the power device is damaged and broken down due to excessive current, causing the valve unit to be in a short-circuit state. However, the protection threshold of the clamping circuit is low, resulting in low efficiency of the transient voltage suppression diode in the clamping circuit under high voltage, and then the heating of the transient voltage suppression diode seriously affects the service life and reliability. At the same time, the low protection threshold of the clamping circuit will cause the maximum DC voltage of the valve unit to be too high when the valve unit is working normally, affecting the voltage utilization rate of the entire valve unit. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a valve unit with a fault protection function, which can adjust the threshold of the clamping unit.

[0006] The present invention also proposes a converter valve system, which can adjust the threshold value of the clamping unit in the event of a fault, so that the corresponding power component is damaged and broken down to present a short-circuit state.

[0007] According to an embodiment of the first aspect of the present invention, a valve unit with a fault protection function includes: a bridge circuit, including at least two power components; a drive control module, connected to the control end of the power component; at least one clamping unit, the clamping unit is connected between the power component and the drive control module; at least one adjustment unit, connected to the clamping unit, and the adjustment unit can adjust the threshold value of the clamping unit.

[0008] The valve unit with fault protection function according to the embodiment of the present invention has at least the following beneficial effects: when a fault occurs, the regulating unit lowers the threshold value of the clamping unit, making the clamping unit more easily broken down, thereby causing the power component connected to the clamping unit to be damaged and broken down to present a short-circuit state. In the case of a fault, the valve unit can be short-circuited by sacrificing the damaged power component, thereby avoiding further expansion of the fault impact and improving reliability. Under normal working conditions, the regulating unit can increase the threshold value of the clamping unit, which is beneficial to improving the efficiency of the clamping unit, reducing the heat generated by the clamping unit, and extending the practical life and reliability. At the same time, increasing the threshold value of the clamping unit is also beneficial to improving the DC voltage utilization rate of the valve unit. In this way, by adjusting the threshold value of the clamping unit, the use requirements can be met both in the case of a fault and in the case of normal working.

[0009] According to some embodiments of the present invention, the clamping unit includes a switch tube Q1 and a plurality of transient voltage suppression diodes, wherein the plurality of transient voltage suppression diodes are connected in series to form a series link, wherein the cathode of the series link is connected to the power component, and the anode of the series link is connected to the control end of the drive control module and / or the power component, and the regulating unit is connected to the control end of the switch tube Q1, and the switch tube Q1 is connected to the series link, and when the switch tube Q1 is turned on, at least one of the transient voltage suppression diodes can be short-circuited.

[0010] According to some embodiments of the present invention, the clamping unit further includes a diode D13, an anode of the diode D13 is connected to the power component, and a cathode of the diode D13 is connected to a cathode of the series link.

[0011] According to some embodiments of the present invention, the regulating unit includes a switch tube Q2 and a resistor R1, one end of the resistor R1 is connected to the power component, the other end of the resistor R1 is respectively connected to the control end of the switch tube Q1 and one end of the switch tube Q2, and the other end of the switch tube Q2 and the control end of the switch tube Q2 are both connected to the drive control module.

[0012] According to some embodiments of the present invention, the clamping unit also includes a resistor R11, a capacitor C11 and a resistor R13, one end of the resistor R11 is respectively connected to one end of the capacitor C11 and the anode of the series link, the other end of the resistor R11 is respectively connected to the other end of the capacitor C11, the control end of the switch tube Q1 and one end of the resistor R13, and the other end of the resistor R13 is connected to the control end of the power component.

[0013] According to some embodiments of the present invention, the clamping unit further includes a trigger circuit, and the control end of the switch tube Q1 is respectively connected to the control end of the power component and the drive control module through the trigger circuit.

[0014] According to some embodiments of the present invention, the trigger circuit includes a resistor R12, a Zener diode ZD11 and a diode D12, one end of the resistor R13 is respectively connected to the drive control module and the control end of the power component, the other end of the resistor R13 is respectively connected to one end of the resistor R12 and the cathode of the Zener diode ZD11, the anode of the Zener diode ZD11 is connected to the anode of the diode D12, and the other end of the resistor R12 is respectively connected to the cathode of the diode D12 and the control end of the switch tube Q1.

[0015] According to some embodiments of the present invention, there are two power components, and the two power components are connected to form a half-bridge circuit. There are two clamping units and the clamping units are connected to the power components one-to-one. There is one adjustment unit, and the clamping unit corresponding to the lower tube in the half-bridge circuit is connected to the adjustment unit.

[0016] According to some embodiments of the present invention, the number of the power components is four, the four power components are connected to form a full-bridge circuit, the number of the clamping units is four and they are connected to the power components in a one-to-one correspondence, and the number of the regulating units is two;

[0017] The two clamping units correspondingly connected to the two lower tubes in the full-bridge circuit are respectively connected to the regulating unit in a one-to-one correspondence;

[0018] Alternatively, the two clamping units correspondingly connected to the two upper tubes in the full-bridge circuit are respectively connected to the regulating unit in a one-to-one correspondence.

[0019] According to the second aspect of the present invention, the converter valve system includes: at least two of the above-mentioned valve units with fault protection function, the bridge circuits are cascaded, and also include a valve control module and a main control module connected to the drive control module in a one-to-one correspondence, and the valve control module is communicatively connected to the main control module.

[0020] The converter valve system according to the embodiment of the present invention has at least the following beneficial effects: when a black fault occurs in a valve unit, in the faulty valve unit, the regulating unit reduces the threshold value of the clamping unit, so that the clamping unit is more easily broken down, and then the power component connected to the clamping unit is damaged and broken down to present a short-circuit state. By sacrificing the damaged power component to make the faulty valve unit short-circuit, other valve units that are working normally are not affected, and the fault is avoided from further expansion, thereby improving reliability. Under normal working conditions, the regulating unit can increase the threshold value of the clamping unit, which is beneficial to improving the efficiency of the clamping unit, reducing the heat generated by the clamping unit, and extending the practical life and reliability. At the same time, increasing the threshold value of the clamping unit is also beneficial to improving the DC voltage utilization rate of the valve unit. In this way, by adjusting the threshold value of the clamping unit, the use requirements can be met both in the case of a fault and in the case of normal operation.

[0021] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0023] Figure 1 A circuit diagram of one embodiment of a valve unit with a fault protection function of the present invention;

[0024] Figure 2 A circuit diagram of one embodiment of a half-bridge circuit of the present invention;

[0025] Figure 3 A circuit diagram of one embodiment of a full-bridge circuit of the present invention;

[0026] Figure 4 A circuit diagram of another embodiment of the full-bridge circuit of the present invention;

[0027] Figure 5 for Figure 3 Schematic diagram of the forward current flow in the circuit diagram;

[0028] Figure 6 for Figure 3 Schematic diagram of reverse current flow in the circuit diagram;

[0029] Figure 7 It is a structural block diagram of one embodiment of the converter valve system of the present invention. DETAILED DESCRIPTION

[0030] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0031] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0032] In the description of the present invention, if there is a description of first and second, it is only for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the sequence of the indicated technical features.

[0033] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0034] like Figures 1 to 4 As shown, a valve unit with a fault protection function according to an embodiment of the present invention includes: a bridge circuit, including at least two power components 100; a drive control module 200, connected to the control end of the power component 100; at least one clamping unit 300, the clamping unit 300 is connected between the power component 100 and the drive control module 200; at least one adjustment unit 400, connected to the clamping unit 300, and the adjustment unit 400 can adjust the threshold value of the clamping unit 300.

[0035] When a fault occurs, the regulating unit 400 lowers the threshold of the clamping unit 300, making the clamping unit 300 more likely to be broken down, thereby causing the power component 100 connected to the clamping unit 300 to be damaged, broken down, and present a short-circuit state. In the event of a black module or the bypass switch 600 failing to operate, the valve unit can be short-circuited by sacrificing the damaged power component 100, thereby avoiding further expansion of the fault impact and improving reliability. Under normal working conditions, the regulating unit 400 can increase the threshold of the clamping unit 300, which is beneficial to improving the efficiency of the clamping unit 300, reducing the heat generated by the clamping unit 300, and extending the practical life and reliability. At the same time, increasing the threshold of the clamping unit 300 is also beneficial to improving the DC voltage utilization rate of the valve unit. In this way, by adjusting the threshold of the clamping unit 300, the use requirements can be met both in the event of a fault and in the event of normal operation.

[0036] The power assembly 100 includes a power tube and a diode connected in reverse parallel to the power tube. Figures 1 to 4 In some embodiments of the present invention, the power tube is an IGBT, the collector of the IGBT is connected to the cathode of the diode, the emitter of the IGBT is connected to the anode of the diode, and the gate of the IGBT is the control terminal.

[0037] The drive control module 200 may be implemented by devices including a single chip microcomputer, FPGA, DSP, CPLD or an embedded chip.

[0038] Reference Figures 1 to 4 In some embodiments of the present invention, the clamping unit 300 includes a switch tube Q1 and a plurality of transient voltage suppression diodes, the plurality of transient voltage suppression diodes are connected in series to form a series link 310, the cathode of the series link 310 is connected to the power component 100, the anode of the series link 310 is connected to the control end of the drive control module 200 and / or the power component 100, the adjustment unit 400 is connected to the control end of the switch tube Q1, the switch tube Q1 is connected to the series link 310, and the conduction of the switch tube Q1 can short-circuit at least one transient voltage suppression diode.

[0039] When the voltage across the transient voltage suppressor diode (TVS) is greater than the breakdown voltage, the current flowing through the transient voltage suppressor diode will increase sharply, while the voltage across the transient voltage suppressor diode remains substantially stable, thereby achieving a clamping effect. A series link 310 is formed by connecting a plurality of transient voltage suppressor diodes in series, and the breakdown voltage of the series link 310 is equal to the sum of the breakdown voltages of each transient voltage suppressor diode, so that the number of transient voltage suppressor diodes can be set according to demand to set the size of the breakdown voltage, and the structure is simple and easy to implement.

[0040] In the event of a fault, the regulating unit 400 controls the switch tube Q1 to turn on, causing at least one transient voltage suppression diode to short-circuit, thereby reducing the breakdown voltage of the series link 310, making the series link 310 more likely to be broken down. After the series link 310 is broken down, a large current flows through the series link 310 to the control end of the drive control module 200 and / or the power component 100, causing the power component 100 to turn on. Under the high current working state, the power component 100 is damaged and broken down, and is in a short-circuit state.

[0041] Under normal working conditions, the regulating unit 400 controls the switch tube Q1 to be cut off, so that the breakdown voltage of the series link 310 increases, which can prevent false triggering under normal working conditions and ensure that the maximum DC voltage of the valve unit can meet the usage requirements when it works normally, which is beneficial to improving voltage utilization.

[0042] Reference Figure 1 In some embodiments of the present invention, the clamping unit 300 further includes a diode D13 , an anode of the diode D13 is connected to the power component 100 , and a cathode of the diode D13 is connected to a cathode of the series link 310 .

[0043] By providing the diode D13 and utilizing the unidirectional conduction characteristic of the diode D13 , the current can only flow to the series link 310 , which helps to make the current flow more stable and improve reliability.

[0044] In the series link 310 , multiple transient voltage suppression diodes are connected in series in the same direction. The cathode of the series link 310 refers to an end connected to the cathode of the transient voltage suppression diode, and the anode of the series link 310 refers to an end connected to the anode of the transient voltage suppression diode.

[0045] Reference Figure 1 In some embodiments of the present invention, the regulating unit includes a switch tube Q2 and a resistor R1, one end of the resistor R1 is connected to the power component 100, the other end of the resistor R1 is connected to the control end of the switch tube Q1 and one end of the switch tube Q2, the other end of the switch tube Q2 and the control end of the switch tube Q2 are both connected to the drive control module 200.

[0046] When a fault such as the bypass switch 600 cannot operate occurs, the drive control module 200 can work normally. The drive control module 200 can control the switch tube Q1 to be turned on through the resistor R21 and the switch tube Q2, so that the breakdown voltage of the clamp unit 300 is reduced, thereby causing the power component 100, that is, the power tube to be damaged and broken down to a short-circuit state. In this way, in the case of a bypass switch 600 failure, the drive control module 200 can actively damage and break down the power tube according to the working state of the valve unit or the superior instruction, which is conducive to improving reliability.

[0047] Reference Figure 1 In some embodiments of the present invention, the clamping unit 300 further includes a resistor R11, a capacitor C11 and a resistor R13, one end of the resistor R11 is respectively connected to one end of the capacitor C11 and the anode of the series link 310, the other end of the resistor R11 is respectively connected to the other end of the capacitor C11, the control end of the switch tube Q1 and one end of the resistor R13, and the other end of the resistor R13 is connected to the control end of the switch tube Q1.

[0048] When a black module appears, that is, when the energy source in the valve unit cannot work, the drive control module 200 cannot work normally to drive the power component 100 to turn on. At this time, when the power component 100 is subjected to a voltage exceeding the breakdown voltage of the series link 310, a large current flows through the series link 310 to the resistor R11 and the capacitor C11, driving the switch tube Q1 to turn on, further increasing the current. At the same time, the current forms a voltage through the resistor R13 to drive the power component 100, that is, the power tube to turn on. The power tube is turned on for a long time under a large current working environment, and then damaged and broken down, and is in a short-circuit state. With this structure, when a black module appears, when the drive control module 200 cannot work normally, the power component 100 can also be damaged and broken down to a short-circuit state, which is conducive to improving reliability.

[0049] Reference Figure 1 In some embodiments of the present invention, the clamping unit 300 further includes a trigger circuit 320 , and the control end of the switch tube Q1 is connected to the control end of the power component 100 and the drive control module 200 through the trigger circuit 320 .

[0050] Since the power component 100, i.e., the power tube, generates spike fluctuations when it is turned off, it may affect other devices in the circuit. In this regard, by providing a trigger circuit 320, the drive control module 200 controls the power component 100, i.e., when the power tube is turned on, the trigger circuit 320 turns on the switch tube Q1, thereby reducing the breakdown voltage of the clamp unit 300. When the drive control module 200 controls the power tube to be turned off and generates spike fluctuations, the breakdown voltage of the clamp unit 300 is still in a reduced state, and the spike fluctuation breaks through the clamp unit 300 and is absorbed by the clamp unit 300, thereby reducing the impact of the spike fluctuation on other devices, which is beneficial to improving reliability. After the power tube is turned off, the switch tube Q1 is also turned off, so that the breakdown voltage of the clamp unit 300 increases, which is beneficial to improving voltage utilization.

[0051] Reference Figure 1In some embodiments of the present invention, the trigger circuit 320 includes a resistor R12, a voltage regulator ZD11 and a diode D12, one end of the resistor R13 is respectively connected to the drive control module 200 and the control end of the power component 100, the other end of the resistor R13 is respectively connected to one end of the resistor R12 and the cathode of the voltage regulator ZD11, the anode of the voltage regulator ZD11 is connected to the anode of the diode D12, and the other end of the resistor R12 is respectively connected to the cathode of the diode D12 and the control end of the switch tube Q1.

[0052] When the driving control module 200 drives the power tube to turn on, the driving control module 200 drives the switch tube Q1 to turn on through the resistor R13, the voltage regulator tube ZD11 and the diode D12, that is, when the power tube is turned on, the breakdown voltage of the clamping unit 300 is reduced. Therefore, when the driving control module 200 controls the power tube to turn off and generates a spike fluctuation, due to factors such as the capacitor C11 and the switch tube Q1 model, the cut-off time point of the switch tube Q1 is later than the cut-off time point of the power tube. When the spike fluctuation is generated, the breakdown voltage of the clamping unit 300 is still in a reduced state. The spike fluctuation can break down the clamping unit 300 and then be absorbed by the clamping unit 300, thereby reducing the impact of the spike fluctuation on other devices, which is conducive to improving reliability.

[0053] refer to Figure 1 In some embodiments of the present invention, a diode D11 and a diode D21 are further included. The anode of the diode D11 is respectively connected to the other end of the resistor R11, the other end of the capacitor C11, the other end of the resistor R12 and the cathode of the diode D12, and the cathode of the diode D11 is connected to the control end of the switch tube Q1; the anode of the diode D21 is respectively connected to the other end of the resistor R1 and one end of the switch tube Q2, and the cathode of the diode D21 is connected to the control end of the switch tube Q1.

[0054] By providing the diode D11 and the diode D21 , the flow direction of the current can be limited according to the unidirectional conduction characteristics of the diode, so that the current flowing through the resistor R1 does not interfere with the current flowing through the resistor R11 or the current flowing through the resistor R13 , which is beneficial to improving reliability.

[0055] refer to Figure 1 In some embodiments of the present invention, a voltage regulator tube ZD21 is further included, wherein an anode of the voltage regulator tube ZD21 is respectively connected to one end of the resistor R11, one end of the capacitor C11 and an anode of the series link 310, and a cathode of the voltage regulator tube ZD21 is respectively connected to the resistor R1, one end of the switch tube Q2 and a control end of the switch tube Q1.

[0056] By providing the voltage regulator tube ZD21, it is possible to prevent the control terminal voltage of the switch tube Q1 from being too high, so as to protect the switch tube Q1 and improve reliability.

[0057] Reference Figure 1 and Figure 2 In some embodiments of the present invention, there are two power components 100, and the two power components 100 are connected to form a half-bridge circuit. There are two clamping units 300, and the clamping units 300 are connected to the power components 100 one by one. There is one adjustment unit 400, and the clamping unit 300 corresponding to the lower tube in the half-bridge circuit is connected to the adjustment unit 400.

[0058] Two power components 100, i.e., two power tubes are connected in series to form a half-bridge circuit. The half-bridge circuit is connected in parallel with a DC capacitor 700, and both power tubes are connected to a clamping unit 300. At the same time, the power tube serving as the lower tube of the half-bridge circuit and the clamping unit 300 connected thereto are also connected to an adjustment unit 400. In this structural case, when a fault occurs, no matter what the direction of the input current is, in the process of the DC capacitor 700 voltage rising due to the fault, the power tube serving as the lower tube of the half-bridge circuit must first bear the voltage of the DC capacitor 700. At this time, the regulating unit 400 reduces the breakdown voltage of the clamping unit 300 corresponding to the lower tube, and the breakdown voltage of the clamping unit 300 corresponding to the upper tube is greater than the breakdown voltage of the clamping unit 300 corresponding to the lower tube, so that the power tube as the lower tube is damaged and broken down to a short-circuit state, that is, a path for the system current is formed, and the voltage of the DC capacitor 700 no longer rises, and the power tube as the upper tube is still in a normal cut-off state, and the current of the DC capacitor 700 will not be released to form a large current, which will affect other devices and cause the scope of the fault to expand. At this time, the faulty valve unit is equivalent to being cut off, and the faulty valve unit no longer affects the operation of the overall system, and there will be no dangerous situation of short-circuit discharge of the DC capacitor 700. At the cost of damaging and breaking down a power tube, the normal and safe operation of the system is maintained, which is conducive to improving reliability.

[0059] Reference Figure 1 , Figure 3 and Figure 4 In some embodiments of the present invention, the number of power components 100 is four, the four power components 100 are connected to form a full-bridge circuit, the number of clamping units 300 is four and connected to the power components 100 in a one-to-one correspondence, and the number of adjustment units 400 is two;

[0060] The two clamping units 300 correspondingly connected to the two lower tubes in the full-bridge circuit are respectively connected to the regulating units 400 in a one-to-one correspondence;

[0061] Alternatively, the two clamping units 300 correspondingly connected to the two upper tubes in the full-bridge circuit are respectively connected to the regulating units 400 in a one-to-one correspondence.

[0062] Four power components 100, namely four power tubes, are connected to form a full-bridge circuit, and each power tube is connected to a clamping unit 300. Figure 3 As an embodiment, the power component 100 includes an IGBT and a diode, IGBT2 and IGBT4 are two lower tubes of the full-bridge circuit, and the two clamping units 300 correspondingly connected thereto are also respectively connected to the regulating units 400 one by one.

[0063] When a fault occurs and the bypass switch 600 fails, the external input current is positive, Figure 3 and Figure 5 , the current flows through the diode D1, the DC capacitor 700, and the diode D4 in sequence. At this time, since the diodes D1 and D4 are turned on, the voltages across IGBT1 and IGBT4 approach zero, and the voltage of the DC capacitor 700 is borne by IGBT2 and IGBT3. As the DC capacitor 700 is charged, the voltage increases. When the voltage is greater than the breakdown voltage of the clamping unit 300 corresponding to IGBT2, IGBT2 is turned on, and the adjustment unit 400 reduces the breakdown voltage of the clamping unit 300, so that the current flowing through IGBT2 is further increased, and the IGBT2 is heated up and damaged and broken down. Due to the existence of the adjustment unit 400, the IGBT2 will be quickly damaged and broken down, while the IGBT3 will not be broken down. At this time, the IGBT1 is still in the off state, so the DC capacitor 700 will not be short-circuited and discharged.

[0064] After IGBT2 is damaged and broken down, when the external input current is reverse, refer to Figure 3 and Figure 6 , the current flows through the diode D3, the DC capacitor 700 and the diode D2 in sequence. Since the diodes D3 and D2 are turned on, the voltage of the DC capacitor 700 is borne by IGBT1 and IGBT4. As the DC capacitor 700 is charged, the voltage increases. When the voltage is greater than the breakdown voltage of the clamping unit 300 corresponding to the IGBT4, the IGBT4 is turned on, and the adjustment unit 400 reduces the breakdown voltage of the clamping unit 300, so that the current flowing through the IGBT4 is further increased, and the IGBT4 is heated up and damaged and broken down. Due to the existence of the adjustment unit 400, the IGBT4 will be quickly damaged and broken down, while the IGBT1 will not be broken down.

[0065] After the above process, IGBT2 and IGBT4 are both damaged and broken down, forming forward and reverse current flow channels, which can make the faulty valve unit short-circuited without affecting the operation of the overall system. The voltage of DC capacitor 700 in the faulty valve unit will not rise again, and the DC capacitor 700 will not have the dangerous situation of short-circuit discharge. In this way, at the cost of sacrificing two IGBT tubes, the system is guaranteed to operate safely in extreme fault conditions such as a black module or the bypass switch 600 failing to work, thereby improving reliability.

[0066] refer to Figure 4 As another embodiment, the power component 100 includes an IGBT tube and a diode, and IGBT1 and IGBT3 are used as two upper tubes of the full bridge circuit, and the two clamping units 300 connected thereto are also connected to the regulating unit 400 one by one. Similar to the embodiment in which the clamping units 300 connected to the regulating unit 400 are connected to the above-mentioned IGBT2 and IGBT4, similarly, by the damage and breakdown of IGBT1 and IGBT3, the forward and reverse flow channels of the current are formed, and at the expense of IGBT1 and IGBT3, the faulty valve unit is in a short-circuit state, and the operation of the overall system is maintained.

[0067] Reference Figure 1 and Figure 7 The converter valve system according to the second aspect of the present invention includes: at least two of the above-mentioned valve units with fault protection function, cascaded bridge circuits, a valve control module 800 and a main control module 500 connected to the drive control module 200 in a one-to-one correspondence, and the valve control module 800 is communicatively connected to the main control module 500.

[0068] When a valve unit fails, in the failed valve unit, the regulating unit 400 reduces the threshold value of the clamping unit 300, making the clamping unit 300 more easily broken down, thereby causing the power component 100 connected to the clamping unit 300 to be damaged, broken down and in a short-circuit state. By sacrificing the damaged power component 100 to make the failed valve unit in a short-circuit state, other valve units that are working normally are not affected, thereby avoiding further expansion of the failure and improving reliability. Under normal working conditions, the regulating unit 400 can increase the threshold value of the clamping unit 300, which is beneficial to improving the efficiency of the clamping unit 300, reducing the heat generated by the clamping unit 300, and extending the practical life and reliability. At the same time, increasing the threshold value of the clamping unit 300 is also beneficial to improving the DC voltage utilization rate of the valve unit. In this way, by adjusting the threshold value of the clamping unit 300, the use requirements can be met in both the case of failure and normal working conditions.

[0069] The main control module 500 is connected to the drive control module 200, and the main control module 500 and the valve control module 800 can be connected via optical fiber communication. The valve control module 800 exchanges data with each main control module 500 to coordinate the normal operation of multiple valve units, so that the overall converter valve can operate stably and reliably.

[0070] The main control module 500 and the valve control module 800 may be implemented by devices including a single chip microcomputer, FPGA, DSP, CPLD or an embedded chip.

[0071] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0072] Of course, the invention is not limited to the above-mentioned embodiments, and those skilled in the art may make equivalent modifications or substitutions without violating the spirit of the invention, and these equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. Valve unit with fault protection function, It is characterized in that include: A bridge circuit comprising at least two power components (100); a drive control module (200) connected to a control end of the power component (100); at least one clamping unit (300), the clamping unit (300) connected between the power component (100) and the drive control module (200); At least one regulating unit (400) is connected to the clamping unit (300), and the regulating unit (400) is capable of regulating the threshold value of the clamping unit (300); the clamping unit (300) comprises a switch tube Q1 and a plurality of transient voltage suppression diodes, the plurality of transient voltage suppression diodes are connected in series to form a series link (310), the cathode of the series link (310) is connected to the power component (100), the anode of the series link (310) is connected to the control end of the drive control module (200) and / or the power component (100), the regulating unit (400) is connected to the control end of the switch tube Q1, the switch tube Q1 is connected to the series link (310), and the switch tube Q1 is turned on to short-circuit at least one of the transient voltage suppression diodes; The regulating unit (400) comprises a switch tube Q2 and a resistor R1, one end of the resistor R1 is connected to the power component (100), the other end of the resistor R1 is respectively connected to the control end of the switch tube Q1 and one end of the switch tube Q2, and the other end of the switch tube Q2 and the control end of the switch tube Q2 are both connected to the drive control module (200).

2. The valve unit with fail-safe function according to claim 1, Features: The clamping unit (300) further comprises a diode D13, wherein an anode of the diode D13 is connected to the power component (100), and a cathode of the diode D13 is connected to a cathode of the series link (310).

3. The valve unit with fail-safe function according to claim 2, Features: The clamping unit (300) further comprises a resistor R11, a capacitor C11 and a resistor R13, one end of the resistor R11 is respectively connected to one end of the capacitor C11 and the anode of the series link (310), the other end of the resistor R11 is respectively connected to the other end of the capacitor C11, the control end of the switch tube Q1 and one end of the resistor R13, and the other end of the resistor R13 is connected to the control end of the power component (100).

4. The valve unit with fail-safe function according to claim 3, Features: The clamping unit (300) further comprises a trigger circuit (320), and the control end of the switch tube Q1 is respectively connected to the control end of the power component (100) and the drive control module (200) through the trigger circuit (320).

5. The valve unit with fail-safe function according to claim 4, Features: The trigger circuit (320) comprises a resistor R12, a voltage regulator tube ZD11 and a diode D12, one end of the resistor R13 is respectively connected to the control end of the drive control module (200) and the power component (100), the other end of the resistor R13 is respectively connected to one end of the resistor R12 and the cathode of the voltage regulator tube ZD11, the anode of the voltage regulator tube ZD11 is connected to the anode of the diode D12, and the other end of the resistor R12 is respectively connected to the cathode of the diode D12 and the control end of the switch tube Q1.

6. The valve unit with fail-safe function according to claim 1, Features: The number of the power components (100) is two, and the two power components (100) are connected to form a half-bridge circuit. The number of the clamping units (300) is two, and the clamping units (300) are connected to the power components (100) in a one-to-one correspondence. The number of the regulating unit (400) is one, and the clamping unit (300) corresponding to the lower tube in the half-bridge circuit is connected to the regulating unit (400).

7. The valve unit with fail-safe function according to claim 1, Features: The number of the power components (100) is four, and the four power components (100) are connected to form a full-bridge circuit; the number of the clamping units (300) is four and they are connected to the power components (100) in a one-to-one correspondence; and the number of the regulating units (400) is two; The two clamping units (300) correspondingly connected to the two lower tubes in the full-bridge circuit are respectively connected to the regulating unit (400) in a one-to-one correspondence; Alternatively, the two clamping units (300) correspondingly connected to the two upper tubes in the full-bridge circuit are respectively connected to the regulating unit (400) in a one-to-one correspondence.

8. Converter valve system, It is characterized in that include: At least two valve units with fault protection function according to any one of claims 1 to 7, wherein the bridge circuits are cascaded, and further include a valve control module (800) and a main control module (500) connected one-to-one with the drive control module (200), and the valve control module (800) is communicatively connected with the main control module (500).

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