Flexible direct current converter valve bypass device and method

Abstract

The invention relates to the technical field of power electronic devices, in particular to a flexible direct current converter valve bypass device and method.The device comprises an energy taking power source, a total energy storage capacitor, a voltage dividing module, a bypass control assembly, a first bypass module and a second bypass module; the energy taking power supply is respectively connected with the total energy storage capacitor, the bypass control assembly and the first bypass module, and is used for receiving the electric energy of the total energy storage capacitor and supplying power to the bypass control assembly and the first bypass module; the voltage dividing module is connected with the total energy storage capacitor, the bypass control assembly and the second bypass module and used for receiving electric energy of the total energy storage capacitor and supplying power to the bypass control assembly and the second bypass module. The bypass control assembly is connected with the first bypass module and the second bypass module and used for responding to the bypass instruction and outputting a driving signal to the first bypass module and the second bypass module, and the technical problem that an existing flexible direct current converter valve bypass scheme is low in reliability is solved.

Description

Technical Field

[0001] This invention relates to the field of power electronic device technology, and in particular to a flexible DC converter valve bypass device and method. Background Technology

[0002] Flexible direct current (DC) transmission technology is a novel DC transmission technology characterized by high reliability, high flexibility, and excellent performance. It has broad development prospects in scenarios such as offshore wind power grid integration, urban power grid transformation, and isolated power supply, and has already achieved widespread application. However, with the continuous commissioning of flexible DC transmission projects, the reliability of the flexible DC converter valve in the system has become a key focus for improvement. Due to the high voltage levels of DC transmission, each arm of the flexible DC converter valve is typically composed of multiple power modules (i.e., sub-modules) connected in series. To ensure the safe operation of the flexible DC converter valve, when an individual sub-module malfunctions, the faulty sub-module needs to be bypassed and disconnected in a timely manner.

[0003] Traditional bypass solutions for submodules utilize a power source and a bypass switch on the bypass drive board. However, when either the power source or the bypass drive board malfunctions, the bypass switch cannot be closed. To address this, existing technologies employ an additional redundant power supply to power the bypass drive board, ensuring continued operation even when the power source fails. However, this redundant power supply increases system size and cost. Furthermore, like the power source, the redundant power supply contains numerous components, posing a risk of component failure. When both the power source and redundant power supply fail, bypassing can only be achieved by breaking down the power switching devices, resulting in low bypass reliability. Therefore, ensuring the bypass reliability of flexible DC converter valves has become a pressing technical problem. Summary of the Invention

[0004] This invention provides a bypass device and method for a flexible DC converter valve, which solves the technical problem of low reliability in existing flexible DC converter valve bypass schemes.

[0005] The present invention provides a bypass device for a flexible DC converter valve, comprising: a power source, a total energy storage capacitor, a voltage divider module, a bypass control component, a first bypass module, and a second bypass module;

[0006] The power source is connected to the total energy storage capacitor, the bypass control component, and the first bypass module, respectively, and is used to receive the electrical energy of the total energy storage capacitor and to supply power to the bypass control component and the first bypass module.

[0007] The voltage divider module is connected to the total energy storage capacitor, the bypass control component, and the second bypass module respectively, and is used to receive the electrical energy of the total energy storage capacitor and supply power to the bypass control component and the second bypass module.

[0008] The bypass control component is connected to the first bypass module and the second bypass module respectively, and is used to respond to the bypass command and output a drive signal to the first bypass module and the second bypass module to close the bypass switch of the first bypass module and the second bypass module.

[0009] Optionally, the first bypass module includes: a bypass main coil energy storage capacitor, a main coil, a first power switching device, and a first drive circuit;

[0010] The bypass main coil energy storage capacitor is connected to the energy harvesting power supply and the main coil, respectively;

[0011] The main coil is connected to the first power switching device, the first power switching device is connected to the first drive circuit, and the first drive circuit is connected to the bypass control component.

[0012] Optionally, the second bypass module includes: a bypass auxiliary coil energy storage capacitor, an auxiliary coil, a second power switching device, and a second drive circuit;

[0013] The bypass auxiliary coil energy storage capacitor is connected to the voltage divider module and the auxiliary coil, respectively;

[0014] The auxiliary coil is connected to the second power switching device, the second power switching device is connected to the second drive circuit, and the second drive circuit is connected to the bypass control component.

[0015] Optionally, the bypass control component includes a first power conversion module, a second power conversion module, and a bypass function circuit;

[0016] The input terminal of the first power conversion module is connected to the power source.

[0017] The output terminal of the first power conversion module is connected to the bypass function circuit;

[0018] The input terminal of the second power conversion module is connected to the voltage divider module;

[0019] The output terminal of the second power conversion module is connected to the bypass function circuit;

[0020] The bypass function circuit is connected to the first bypass module and the second bypass module respectively.

[0021] Optionally, the voltage divider module includes: a first voltage divider resistor, a second voltage divider resistor, and a third voltage divider resistor;

[0022] One end of the first voltage divider resistor is connected to the total energy storage capacitor, and the other end of the first voltage divider resistor is connected to one end of the second voltage divider resistor and the bypass control component, respectively.

[0023] The other end of the second voltage divider resistor is connected to one end of the third voltage divider resistor and the second bypass module, respectively;

[0024] The other end of the third voltage divider resistor is grounded.

[0025] Optionally, it may also include a first diode and a second diode;

[0026] The power source is connected to the anode of the first diode, and the cathode of the first diode is connected to the bypass control component.

[0027] The power source is connected to the anode of the second diode, and the cathode of the second diode is connected to the first bypass module.

[0028] Optionally, it also includes a third diode and a fourth diode;

[0029] The voltage divider module is connected to the anode of the third diode, and the cathode of the third diode is connected to the bypass control component;

[0030] The voltage divider module is connected to the anode of the fourth diode, and the cathode of the fourth diode is connected to the second bypass module.

[0031] Optionally, it also includes a submodule central control board; the power supply and the bypass control component are respectively connected to the submodule central control board.

[0032] Optionally, it also includes: a fifth diode;

[0033] The output terminal of the second power conversion module is connected to the anode of the fifth diode, and the cathode of the fifth diode is connected to the control board of the submodule.

[0034] Another aspect of the present invention provides a bypass method for a flexible DC converter valve, applied to the device described above, comprising:

[0035] The bypass control component responds to the bypass command and outputs a drive signal to the first bypass module and the second bypass module, causing the first bypass module and the second bypass module to close the bypass switch.

[0036] As can be seen from the above technical solutions, the present invention has the following advantages:

[0037] The present invention provides a bypass device for a flexible DC converter valve, comprising: a power source, a total energy storage capacitor, a voltage divider module, a bypass control component, a first bypass module, and a second bypass module;

[0038] The power source is connected to the total energy storage capacitor, the bypass control component, and the first bypass module, respectively, and is used to receive the electrical energy from the total energy storage capacitor and supply power to the bypass control component and the first bypass module; the voltage divider module is connected to the total energy storage capacitor, the bypass control component, and the second bypass module, respectively, and is used to receive the electrical energy from the total energy storage capacitor and supply power to the bypass control component and the second bypass module; the bypass control component is connected to the first bypass module and the second bypass module, respectively, and is used to respond to bypass commands and output drive signals to the first bypass module and the second bypass module.

[0039] In this invention, the power source and the voltage divider module simultaneously supply power to the bypass control component. Therefore, when the power source fails, the bypass control component can still operate normally based on the power supplied by the voltage divider module. This avoids the situation in traditional bypass solutions where the bypass switch cannot be closed when the power source fails. Furthermore, in this invention, the voltage divider module is connected to the total energy storage capacitor in the original power transmission path between the power source and the voltage divider module. This allows the voltage divider module to receive energy from the total energy storage capacitor to power the bypass control component and the second bypass module. Therefore, this invention utilizes the existing power supply to construct a new power transmission path, eliminating the need for redundant power supplies, simplifying the system topology, and avoiding the increased system size and cost associated with existing bypass solutions that use additional redundant power supplies. Simultaneously, this invention supplies power based on the voltage divider module's voltage-dividing function, avoiding the failure of redundant power supplies in existing bypass solutions, and significantly improving bypass reliability. Furthermore, in this invention, the first bypass module receives power from the energy source, and the second bypass module receives power from the voltage divider module. When bypassing is required, the bypass control component responds to the bypass command and simultaneously drives the first and second bypass modules to close the bypass switch. Based on this circuit structure, when the energy source fails and causes the first bypass module to lose power, the drive signal output by the bypass control component can drive the second bypass module to close the bypass switch. When the energy source is normal, the bypass control component can simultaneously drive the first and second bypass modules to close the bypass switch. Therefore, regardless of whether the energy source fails or is normal, the closing efficiency of the bypass switch will not be affected, avoiding the situation in the prior art where the voltage stress of the bypass switch increases due to closing delay, thus improving the reliability of the bypass.

[0040] As can be seen from the above, the flexible DC converter valve bypass device provided by the present invention solves the technical problem of low reliability of existing flexible DC converter valve bypass schemes. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 One of the structural diagrams of a flexible DC converter valve bypass device provided in an embodiment of the present invention;

[0043] Figure 2 This is the second structural diagram of a flexible DC converter valve bypass device provided in an embodiment of the present invention;

[0044] Figure 3 The third structural diagram of a flexible DC converter valve bypass device provided in this embodiment of the invention;

[0045] In the diagram, 1 is the power source; 2 is the total energy storage capacitor; 3 is the voltage divider module; 4 is the bypass control component; 5 is the first bypass module; 6 is the second bypass module; 7 is the sub-module central control board; 8 is the IGBT driver board; 41 is the first power conversion module; 42 is the second power conversion module; 43 is the bypass function circuit; 51 is the bypassed main coil energy storage capacitor; 52 is the main coil; 61 is the bypassed auxiliary coil energy storage capacitor; 62 is the auxiliary coil; 71 is the sub-module power conversion module; 72 is the sub-module function circuit; R1 is the first voltage divider resistor; R2 is the second voltage divider resistor; R3 is the third voltage divider resistor; D2 is the second diode; D4 is the fourth diode. Detailed Implementation

[0046] In existing bypass schemes, another bypass scheme without redundant power supply has been proposed. This scheme achieves bypass in case of power supply failure by using a fault re-triggering circuit that incorporates a first bypass coil and a second bypass coil. However, in the fault re-triggering circuit, the first and second bypass coils are triggered sequentially. Specifically, when the first bypass coil and its triggering circuit fail to operate, the second bypass coil will not trigger immediately. Instead, it will wait for the bus capacitor voltage to continue rising until it reaches the triggering threshold voltage of the second bypass coil. Only then will the second bypass coil operate as a backup triggering circuit to close the bypass switch. This triggering method leads to a delay in the closing time of the bypass switch. As the bus capacitor voltage continues to increase, the voltage stress experienced by the bypass switch during closing increases, increasing the risk and reducing reliability.

[0047] This invention provides a bypass device and method for a flexible DC converter valve, which solves the technical problem of low reliability in existing flexible DC converter valve bypass schemes.

[0048] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0049] Please see Figure 1 The present invention provides a bypass device for a flexible DC converter valve, comprising: a power source 1, a total energy storage capacitor 2, a voltage divider module 3, a bypass control component 4, a first bypass module 5, and a second bypass module 6; the power source 1 is connected to the total energy storage capacitor 2, the bypass control component 4, and the first bypass module 5 respectively, for receiving the electrical energy of the total energy storage capacitor 2 and supplying power to the bypass control component 4 and the first bypass module 5; the voltage divider module 3 is connected to the total energy storage capacitor 2, the bypass control component 4, and the second bypass module 6 respectively, for receiving the electrical energy of the total energy storage capacitor 2 and supplying power to the bypass control component 4 and the second bypass module 6; the bypass control component 4 is connected to the first bypass module 5 and the second bypass module 6 respectively, for responding to bypass commands and outputting drive signals to the first bypass module 5 and the second bypass module 6, causing the first bypass module 5 and the second bypass module 6 to close the bypass switch.

[0050] It should be noted that the total energy storage capacitor 2, also known as the high-voltage energy storage capacitor, is used to supply power to the power source 1 and the voltage divider module 3. The power source 1 obtains power from the total energy storage capacitor 2 and transmits it to the bypass control component 4 and the first bypass module 5, respectively, to power them. The voltage divider module 3 has a voltage dividing function. Based on its own voltage dividing characteristics, it converts the voltage received from the total energy storage capacitor 2 into a voltage suitable for the operation of the bypass control component 4 and the second bypass module 6, thus supplying power to them. When energized, the bypass control component 4 can generate a corresponding drive signal based on the received bypass command, thereby driving the first bypass module 5 and the second bypass module 6 to close the bypass switches. The first bypass module 5 and the second bypass module 6 are internally equipped with components for controlling the closing of the bypass switches. When energized, they can close the bypass switches based on the received drive signal.

[0051] The working principle of this embodiment is as follows:

[0052] Assuming a fault occurs in the flexible DC converter submodule requiring bypass, when the flexible DC converter valve bypass device provided in this embodiment is operating normally without faults, the power supply 1 draws power from the total energy storage capacitor 2 and outputs a voltage to power the bypass control component 4 and the first bypass module 5. The voltage divider module 3 draws power from the total energy storage capacitor 2 and powers the bypass control component 4 and the second bypass module 6. Therefore, the bypass control component 4, the first bypass module 5, and the second bypass module 6 can all obtain power. The bypass control component 4 can receive the bypass command and generate a drive signal in response to the bypass command, and simultaneously output the drive signal to the first bypass module 5 and the second bypass module 6. The first bypass module 5 and the second bypass module 6 both receive the drive signal, and therefore both drive the bypass switch to close. When the power source 1 fails, it cannot supply power to the bypass control component 4 and the first bypass module 5. However, the voltage divider module 3 can still supply power to the bypass control component 4 and the second bypass module 6. Therefore, in the event of a power source 1 failure, the bypass control component 4 can still receive bypass commands and generate drive signals in response to the bypass commands. The drive signals are then simultaneously output to the first bypass module 5 and the second bypass module 6. At this time, the first bypass module 5 cannot drive the bypass switch to close due to power loss, while the second bypass module 6, based on the power provided by the voltage divider module 3, can operate normally. Therefore, the second bypass module 6 responds to the received drive signals and drives the bypass switch to close. Based on this, it can be seen that in this embodiment, regardless of whether the power source 1 fails or not, the bypass switch can be closed promptly and quickly when a bypass faulty submodule is required, without affecting the closing efficiency. This avoids the situation in the prior art where the voltage stress on the bypass switch increases due to closing delay, thus improving the reliability of the bypass.

[0053] Therefore, the flexible DC converter valve bypass device provided in this embodiment supplies power to the bypass control component 4 simultaneously through the power source 1 and the voltage divider module 3. Thus, when the power source 1 fails, the bypass control component 4 can still operate normally based on the power supplied by the voltage divider module 3, avoiding the situation in traditional bypass technology where the bypass switch cannot be closed when the power source 1 fails. Moreover, in this embodiment, based on the connection between the voltage divider module 3 and the total energy storage capacitor 2 in the original power transmission path of the power source 1, the voltage divider module 3 can receive the power from the total energy storage capacitor 2 to supply power to the bypass control component 4 and the second bypass module 6. Therefore, this embodiment utilizes the original power supply to construct a new power transmission path, eliminating the need to introduce redundant power supplies, simplifying the system topology, and avoiding the situation in existing bypass schemes where additional redundant power supplies are used, leading to increased system size and cost. At the same time, this embodiment supplies power based on the voltage divider function of the voltage divider module 3, avoiding the failure of redundant power supplies in existing bypass schemes, and greatly improving bypass reliability. Furthermore, in this embodiment, the first bypass module 5 receives power from the power source 1, and the second bypass module 6 receives power from the voltage divider module 3. When bypassing is required, the bypass control component 4 responds to the bypass command and simultaneously drives the first bypass module 5 and the second bypass module 6 to close the bypass switch. Based on this circuit structure, when the power source 1 fails and causes the first bypass module 5 to lose power, the drive signal output by the bypass control component 4 can drive the second bypass module 6 to close the bypass switch. When the power source 1 is normal, the bypass control component 4 can simultaneously drive the first bypass module 5 and the second bypass module 6 to close the bypass switch. Therefore, regardless of whether the power source 1 is faulty or normal, it will not affect the closing efficiency of the bypass switch, avoiding the situation in the prior art where the voltage stress of the bypass switch increases due to the closing delay, thus improving the reliability of the bypass.

[0054] In one embodiment, the voltage divider module 3 includes: a first voltage divider resistor R1, a second voltage divider resistor R2, and a third voltage divider resistor R3;

[0055] One end of the first voltage divider resistor R1 is connected to the total energy storage capacitor 2, and the other end of the first voltage divider resistor R1 is connected to one end of the second voltage divider resistor R2 and the bypass control component 4, respectively.

[0056] The other end of the second voltage divider resistor R2 is connected to one end of the third voltage divider resistor R3 and the second bypass module 6, respectively.

[0057] The other end of the third voltage divider resistor R3 is grounded.

[0058] It should be noted that the voltage divider module 3 draws power from the total energy storage capacitor 2 and, based on the voltage divider effect, converts the voltage of the total energy storage capacitor 2 into a first target voltage and a second target voltage. The first target voltage is used to power the second power conversion module 42 in the bypass control component 4, and the second target voltage is used to power the bypass auxiliary coil energy storage capacitor 61 in the second bypass module 6.

[0059] Specifically, such as Figure 2 As shown, the first voltage-dividing resistor R1, the second voltage-dividing resistor R2, and the third voltage-dividing resistor R3 are connected in series, and then connected in parallel across the total energy storage capacitor 2. The first target voltage V5 and the second target voltage V7 are obtained based on the voltage division effect of the first voltage-dividing resistor R1, the second voltage-dividing resistor R2, and the third voltage-dividing resistor R3. Specifically, the connection point of the first voltage-dividing resistor R1 and the second voltage-dividing resistor R2 outputs the first target voltage V5 and the second target voltage V7.

[0060] In one embodiment, the bypass control component 4 includes a first power conversion module 41, a second power conversion module 42, and a bypass function circuit 43.

[0061] The input terminal of the first power conversion module 41 is connected to the power source 1;

[0062] The output terminal of the first power conversion module 41 is connected to the bypass function circuit 43;

[0063] The input terminal of the second power conversion module 42 is connected to the voltage divider module 3;

[0064] The output terminal of the second power conversion module 42 is connected to the bypass function circuit 43;

[0065] The bypass function circuit 43 is connected to the first bypass module 5 and the second bypass module 6 respectively.

[0066] It should be noted that, as Figure 2 As shown, under normal operating conditions, the power source 1 draws power from the total energy storage capacitor and outputs a voltage V3. This voltage V3 is divided into two paths: one path inputs to the first power conversion module 41 to supply power to the first power conversion module 41, and the other path inputs to the first bypass module 5 to supply power to the bypassed main coil energy storage capacitor 51 in the first bypass module 5.

[0067] The first power conversion module 41 is connected to the power source 1 and is used to convert the voltage V3 transmitted by the power source 1 into the third target voltage V4, and transmit the third target voltage V4 to the bypass function circuit 43 to power the bypass function circuit 43.

[0068] The second power conversion module 42 is connected to the connection of the first voltage divider resistor R1 and the second voltage divider resistor R2. It is used to convert the first target voltage V5 output from the connection of the first voltage divider resistor R1 and the second voltage divider resistor R2 into the fourth target voltage V6, and transmit the fourth target voltage V6 to the bypass function circuit 43 to power the bypass function circuit 43.

[0069] The bypass function circuit 43 is used to respond to the bypass command and output a drive signal to the main coil 52 in the first bypass module 5 and the auxiliary coil 62 in the second bypass module 6.

[0070] It is understood that the third target voltage V4 and the fourth target voltage V6 can be determined based on the operating voltage of the bypass function circuit 43. The third target voltage V4 and the fourth target voltage V6 can be the same value. Under normal circumstances, the bypass function circuit 43 always receives the third target voltage V4 and the fourth target voltage V6.

[0071] In one example, the bypass function circuit 43 can set the usage priority of the third target voltage V4 and the fourth target voltage V6. For example, it can set the third target voltage V4 to be used first, so that the fourth target voltage V6 is a redundant supply voltage.

[0072] In one embodiment, the first bypass module 5 includes: a bypass main coil energy storage capacitor 51, a main coil 52, a first power switching device, and a first drive circuit;

[0073] The bypass main coil energy storage capacitor 51 is connected to the power source 1 and the main coil 52 respectively;

[0074] The main coil 52 is connected to the first power switching device, the first power switching device is connected to the first drive circuit, and the first drive circuit is connected to the bypass control component 4.

[0075] It should be noted that the main coil 52 is specifically the main coil of the bypass switch. When the main coil 52 is energized, it drives the bypass switch to close. The positive terminal of the bypass main coil energy storage capacitor 51 is connected to the positive envelope of the main coil 52, and the negative envelope of the main coil 52 is connected to one end of the first power switching device. The other end of the first power switching device is connected to the negative terminal of the bypass main coil energy storage capacitor 51, forming a circuit. The control terminal of the first power switching device is connected to the first drive circuit. The first power switching device has an on state and an off state. When the first power switching device is driven to conduct, the circuit is open, the main coil 52 is energized, and thus the bypass switch is driven to close.

[0076] like Figure 2As shown, the voltage V3 output by the power supply 1, the first power conversion module 41, and the bypass main coil energy storage capacitor 51 constitute the main coil power supply system, which is responsible for providing energy to the main coil 52. The first power switching device is controlled by the first drive circuit, thereby switching the energized and de-energized states of the main coil 52 to switch the opening and closing of the bypass switch.

[0077] In one example, the first power switching device can be a thyristor or other controllable power switching device. Taking a thyristor as an example, the anode of the first power switching device is connected to the negative envelope of the main coil 52, the cathode of the first power switching device is connected to the negative terminal of the bypass main coil energy storage capacitor 51, and the gate of the first power switching device is connected to the first drive circuit. Figure 3 As shown, Figure 3 In this circuit, SCR1 is the first power switching device, and the SCR1 driving circuit is the first driving circuit.

[0078] In one embodiment, it further includes a first diode and a second diode D2;

[0079] The power source 1 is connected to the anode of the first diode, and the cathode of the first diode is connected to the bypass control component 4.

[0080] The power source 1 is connected to the anode of the second diode D2, and the cathode of the second diode D2 is connected to the first bypass module 5.

[0081] It should be noted that the power source 1 is connected to the anode of the first diode, and the cathode of the first diode is connected to the input terminal of the first power conversion module 41, so that the power source 1 is connected to the first power conversion module 41 through the first diode. Specifically, the output voltage V3 of the power source 1 is transmitted to the input terminal of the first power conversion module 41 through the first diode. It can be understood that... Figure 2 The first diode is not shown.

[0082] like Figure 3 As shown, the power supply 1 is connected to the anode of the second diode D2, and the cathode of the second diode D2 is connected to the positive terminal of the bypass main coil energy storage capacitor 51. Specifically, the output voltage V3 of the power supply 1 is transmitted to the bypass main coil energy storage capacitor 51 through the second diode D2.

[0083] In this embodiment, both the first diode and the second diode D2 are used to prevent repeated discharge between the output capacitor of the power supply 1 and the internal capacitor of the first power conversion module 41 and the bypass main coil energy storage capacitor 51.

[0084] In one embodiment, the second bypass module 6 includes: a bypass auxiliary coil energy storage capacitor 61, an auxiliary coil 62, a second power switching device, and a second drive circuit;

[0085] The bypass auxiliary coil energy storage capacitor 61 is connected to the voltage divider module 3 and the auxiliary coil 62 respectively;

[0086] The auxiliary coil 62 is connected to the second power switching device, the second power switching device is connected to the second drive circuit, and the second drive circuit is connected to the bypass control component 4.

[0087] It should be noted that the auxiliary coil 62 is specifically the auxiliary coil of the bypass switch. When the auxiliary coil 62 is energized, it drives the bypass switch to close. It can be understood that the bypass switch contains a main coil 52 and an auxiliary coil 62. When either the main coil 52 or the auxiliary coil 62 is energized, it will drive the bypass switch to close.

[0088] The positive terminal of the bypass auxiliary coil energy storage capacitor 61 is connected to the junction of the second voltage divider resistor R2 and the third voltage divider resistor R3 in the voltage divider module 3, and is also connected to the positive envelope of the auxiliary coil 62. The negative envelope of the auxiliary coil 62 is connected to one end of the second power switch device, and the other end of the second power switch device is connected to the negative terminal of the bypass auxiliary coil energy storage capacitor 61, forming a loop. The control terminal of the second power switch device is connected to the second drive circuit. The second power switch device has an on state and an off state. When the second power switch device is driven to conduct, the loop is open, the auxiliary coil 62 is energized, and thus the bypass switch is driven to close.

[0089] like Figure 2 As shown, the auxiliary coil power supply system, consisting of the first target voltage V5 and the second target voltage V7 output by the voltage divider module 3, the second power conversion module 42, and the bypass auxiliary coil energy storage capacitor 61, is responsible for providing energy to the auxiliary coil 62. The second power switching device is controlled by the second drive circuit, thereby switching the energized and de-energized states of the auxiliary coil 62 to switch the opening and closing of the bypass switch.

[0090] In one example, the second power switching device can be a thyristor or other controllable power switching device. Taking a thyristor as an example, the anode of the second power switching device is connected to the negative envelope of the auxiliary coil 62, the cathode of the second power switching device is connected to the negative terminal of the bypass auxiliary coil energy storage capacitor 61, and the gate of the second power switching device is connected to the second drive circuit. Figure 3 As shown, Figure 3 In this circuit, SCR2 is the second power switching device, and the SCR2 driving circuit is the second driving circuit.

[0091] In this embodiment, the first driving circuit and the second driving circuit receive the same driving signal from the bypass function circuit 43, driving the first power switching device and the second power switching device to turn on, thereby driving the bypass switch to close.

[0092] In one embodiment, a third diode and a fourth diode D4 are also included;

[0093] Voltage divider module 3 is connected to the anode of the third diode, and the cathode of the third diode is connected to the bypass control component 4;

[0094] Voltage divider module 3 is connected to the anode of the fourth diode D4, and the cathode of the fourth diode D4 is connected to the second bypass module 6.

[0095] It should be noted that the connection point of the first voltage-dividing resistor R1 and the second voltage-dividing resistor R2 in the voltage divider module 3 is connected to the anode of the third diode, and based on the connection relationship between the cathode of the third diode and the input terminal of the second power conversion module 42 in the bypass control component 4, it is connected to the input terminal of the second power conversion module 42. Specifically, the first target voltage V5 output by the voltage divider module 3 is input to the input terminal of the second power conversion module 42 after passing through the third diode. This is understandable. Figure 2 The third diode is not shown.

[0096] like Figures 2 to 3 As shown, the connection point between the second voltage divider resistor R2 and the third voltage divider resistor R3 in the voltage divider module 3 is connected to the anode of the fourth diode D4, and the cathode of the fourth diode D4 is connected to the positive terminal of the bypass auxiliary coil energy storage capacitor 61 in the second bypass module 6. Specifically, the second target voltage V7 output by the voltage divider module 3 is transmitted to the bypass auxiliary coil energy storage capacitor 61 through the fourth diode D4.

[0097] In this embodiment, the third diode and the fourth diode D4 function similarly to the first diode and the second diode D2, in order to prevent repeated discharge between capacitors.

[0098] In one embodiment, the system further includes a submodule central control board 7; the power supply 1 and the bypass control component 4 are respectively connected to the submodule central control board 7.

[0099] It should be noted that the submodule central control board 7 is used to monitor the operating status of each submodule in the flexible DC converter valve. When a fault is detected in a submodule, a bypass command is output to the bypass function unit corresponding to the faulty submodule to realize the bypass of the faulty submodule.

[0100] In this embodiment, the submodule control board 7 includes a submodule power conversion module 71 and a submodule functional circuit 72. The submodule power conversion module 71 is connected to the power source 1 and the second power conversion module 42 in the bypass control component 4. The submodule functional power supply is connected to the bypass functional circuit 43 in the bypass control component 4 and is used to output bypass commands to the bypass functional circuit 43.

[0101] Specifically, the power source 1 draws power from the total energy storage capacitor 2 and outputs a voltage V2 to the submodule power conversion module 71 to power the submodule central control board 7. The second power conversion module 42 of the bypass control component 4 transmits the converted fourth target voltage V6 to the submodule central control board 7 to power the submodule central control board 7.

[0102] Therefore, when a power supply failure occurs during the startup phase (i.e., the power source 1 fails), the submodule central control board 7 continues to be powered by the fourth target voltage V6 output by the second power conversion module 42, enabling the submodule central control board 7 to operate normally and perform functions such as sending bypass commands and reporting fault information. Furthermore, the submodule central control board 7 can still send bypass commands to the bypass function circuit 43, prompting the bypass function circuit 43 to drive the bypass switch to close, further improving the reliability of closing the switch during power supply failures.

[0103] In one embodiment, it further includes: a fifth diode;

[0104] The output terminal of the second power conversion module 42 is connected to the anode of the fifth diode, and the cathode of the fifth diode is connected to the sub-module control board 7.

[0105] It should be noted that the second power conversion module 42 is connected to the sub-module power conversion module 71 of the sub-module central control board 7 via the fifth diode, so that the fourth target voltage V6 output by the second power conversion module 42 is transmitted to the sub-module power conversion module 71 via the fifth diode, providing redundant power supply to the sub-module central control board 7. This is understandable. Figure 2 The fifth diode is not shown.

[0106] In this embodiment, the fifth diode functions similarly to the third and fourth diodes D4, to prevent repeated discharge between capacitors.

[0107] In one embodiment, the first power conversion module 41, the second power conversion module 42, the bypass function circuit 43, the bypass main coil energy storage capacitor 51, and the bypass auxiliary coil energy storage capacitor 61 can also be integrated on the bypass switch driver board.

[0108] In one embodiment, the bypass function circuit 43 is also used to collect the status information of the bypass switch, detect the key parameters of the bypass switch, and report the status information, key parameters, and fault information of the bypass switch to the submodule control board 7.

[0109] In one embodiment, the bypass function circuit 43 is connected to the bypass main coil energy storage capacitor 51 and the bypass auxiliary coil energy storage capacitor 61 to monitor the status of the bypass main coil energy storage capacitor 51 and the bypass auxiliary coil energy storage capacitor 61.

[0110] In one embodiment, the system further includes an IGBT driver board 8, with the power supply 1 connected to the IGBT driver board 8 to provide power to the IGBT board. The IGBT board is used to drive the various power switching devices in the submodule.

[0111] It should be noted that, as Figure 2 As shown, during normal operation, the power supply 1 draws power from the total energy storage capacitor 2 and outputs a voltage V1 to power the IGBT driver board 8.

[0112] The above is a structural description of a flexible DC-DC converter valve bypass device provided by an embodiment of the present invention. The working principle of the flexible DC-DC converter valve bypass device provided by the present invention will be illustrated below with reference to the above embodiments.

[0113] When the submodule is running normally, the power supply 1 draws power from the total energy storage capacitor 2 and outputs a voltage V1 to power the IGBT driver board 8. At the same time, it outputs a voltage V2 to power the submodule central control board 7 and outputs a voltage V3 to power the bypass driver board.

[0114] After voltage V3 enters the bypass driver board, it splits into two paths. One path powers the first power conversion module 41 through the first diode, and the other path powers the bypass main coil energy storage capacitor 51 through the second diode D2. The first power conversion module 41 outputs the third target voltage V4 to power the bypass function circuit 43 inside the bypass switch driver board. The bypass function circuit 43 can realize the specific functions of the bypass driver board, receive bypass commands from the sub-module central control board 7, feed back the bypass switch status to the sub-module central control board 7, detect key parameters, and report fault information.

[0115] When the submodule is running normally, each voltage divider resistor draws power from the total energy storage capacitor 2 and outputs a first target voltage V5, which supplies power to the second power conversion module 42 in the bypass switch driver board through the third diode, and outputs a second target voltage V7, which supplies power to the bypass auxiliary coil energy storage capacitor 61 in the bypass switch driver board through the fourth diode D4.

[0116] When the submodule is running normally, the bypass main coil energy storage capacitor 51 and the bypass auxiliary coil energy storage capacitor 61 are always in a charging state. The bypass function circuit 43 inside the bypass switch driver board always receives the third target voltage V4 output by the first power conversion module 41 and the fourth target voltage V6 output by the second power conversion module 42, and prioritizes the use of the third target voltage V4.

[0117] When the bypass switch driver board detects an external bypass command or bus capacitor overvoltage, the internal bypass function circuit 43 generates a drive signal and outputs it to the first drive circuit and the second drive circuit simultaneously, causing the first power switch device and the second power switch device to conduct simultaneously. The main coil 52 and the auxiliary coil 62 in the bypass switch are triggered simultaneously, completing the bypass switch closing operation.

[0118] When a power supply failure occurs during startup (i.e., power source 1 fails), voltages V1, V2, V3, and the third target voltage V4 have no output. The bypass function circuit 43 inside the bypass switch driver board continues to be powered by the fourth target voltage V6, enabling functions such as command reception and bus capacitor voltage monitoring. When a bus capacitor overvoltage is detected or an external bypass command is received, the bypass function circuit 43 generates a drive signal and simultaneously outputs it to the first and second drive circuits, turning on the second power switching device and triggering the auxiliary coil 62 in the bypass switch to complete the bypass switch closing operation.

[0119] When a power supply failure occurs during the startup phase (i.e., a failure of power source 1), the submodule central control board 7 continues to be powered by the fourth target voltage V6, which can realize functions such as sending bypass commands and reporting fault information. Furthermore, the submodule central control board 7 can still send bypass commands to the bypass switch driver board, prompting the bypass switch driver board to drive the bypass switch to close, further improving the reliability of closing during power supply failures.

[0120] This invention also provides a bypass method for a flexible DC converter valve, applied to the apparatus of any of the above embodiments, comprising:

[0121] The bypass control component responds to the bypass command and outputs a drive signal to the first bypass module and the second bypass module, causing the first bypass module and the second bypass module to close the bypass switch.

[0122] Based on the above, this invention proposes a bypass device and method for a flexible DC converter valve. It employs an auxiliary coil power supply system powered by a voltage divider resistor, eliminating the need for additional redundant power supplies. Furthermore, by simultaneously triggering the first and second power switching devices, it enables submodule bypass during system startup in case of power supply failure, achieving the same bypass effect as when the power supply system is normal. This improves the speed and reliability of bypass switch closing, solving the problems of existing bypass methods that cannot achieve bypass switch closing during startup power supply failures, or those that, when bypass switch closing is not powered, suffer from sequential triggering of the bypass switch coils, leading to delayed closing time, increased risk, and lower reliability. Compared to existing technologies, this invention uses the same drive signal to trigger the first power switching device of the main coil and the second power switching device of the auxiliary coil. Once the bypass threshold voltage is reached, the bypass drive board immediately drives the bypass switch to close, ensuring both speed and reliability of bypass switch closing.

[0123] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or modules may be electrical, mechanical, or other forms.

[0124] The modules described as separate components may or may not be physically separate. Similarly, the components shown as modules may or may not be physical modules; they may be located in one place or distributed across multiple network modules. Some or all of the modules can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0125] Furthermore, the functional modules in the various embodiments of the present invention can be integrated into one processing module, or each functional module can exist as a separate physical entity, or two or more functional modules can be integrated into one processing module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0126] If the integrated module is implemented as a software functional module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0127] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or modules is not necessarily limited to those steps or modules explicitly listed, but may include other steps or modules not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0128] It should also be noted that in the description of this invention, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0129] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A line-commutated converter valve bypass arrangement, characterized by The bypass control assembly is connected with the first bypass module and the second bypass module, and is used for outputting a driving signal to the first bypass module and the second bypass module to make the first bypass module and the second bypass module close the bypass switch in response to a bypass instruction. The bypass control assembly comprises a first power conversion module, a second power conversion module and a bypass function circuit. The input end of the first power conversion module is connected with the energy-taking power supply. The output end of the first power conversion module is connected with the bypass function circuit. The input end of the second power conversion module is connected with the voltage division module.

2. The apparatus of claim 1, wherein, The output end of the second power conversion module is connected with the bypass function circuit. The bypass function circuit is connected with the first bypass module and the second bypass module. The bypass control assembly comprises a first power conversion module, a second power conversion module and a bypass function circuit.

3. The apparatus of claim 2, wherein, The input end of the first power conversion module is connected with the energy-taking power supply. The output end of the first power conversion module is connected with the bypass function circuit. The input end of the second power conversion module is connected with the voltage division module.

4. The apparatus of claim 3, wherein, The output end of the second power conversion module is connected with the bypass function circuit. The bypass function circuit is connected with the first bypass module and the second bypass module. The bypass control assembly comprises a first power conversion module, a second power conversion module and a bypass function circuit. The input end of the first power conversion module is connected with the energy-taking power supply. The output end of the first power conversion module is connected with the bypass function circuit. The input end of the second power conversion module is connected with the voltage division module.

5. The apparatus of claim 4, wherein, The output end of the second power conversion module is connected with the bypass function circuit. The bypass function circuit is connected with the first bypass module and the second bypass module. The bypass control assembly comprises a first power conversion module, a second power conversion module and a bypass function circuit. The input end of the first power conversion module is connected with the energy-taking power supply.

6. The apparatus of claim 5, wherein, The output end of the first power conversion module is connected with the bypass function circuit. The input end of the second power conversion module is connected with the voltage division module. The output end of the second power conversion module is connected with the bypass function circuit.

7. The apparatus of claim 6, wherein, The bypass function circuit is connected with the first bypass module and the second bypass module. The bypass control assembly comprises a first power conversion module, a second power conversion module and a bypass function circuit. The input end of the first power conversion module is connected with the energy-taking power supply. The output end of the first power conversion module is connected with the bypass function circuit. The input end of the second power conversion module is connected with the voltage division module. The output end of the second power conversion module is connected with the bypass function circuit. The bypass function circuit is connected with the first bypass module and the second bypass module. The bypass control assembly comprises a first power conversion module, a second power conversion module and a bypass function circuit. The input end of the first power conversion module is connected with the energy-taking power supply. The output end of the first power conversion module is connected with the bypass function circuit. The input end of the second power conversion module is connected with the voltage division module. The output end of the second power conversion module is connected with the bypass function circuit. The bypass function circuit is connected with the first bypass module and the second bypass module. The bypass control assembly comprises a first power conversion module, a second power conversion module and a bypass function circuit. The input end of the first power conversion module is connected with the energy-taking power supply. The output end of the first power conversion module is connected with the bypass function circuit. The input end of the second power conversion module is connected with the voltage division module. The output end of the second power conversion module is connected with the bypass function circuit. The bypass function circuit is connected with the first bypass module and the second bypass module. The bypass control assembly comprises a first power conversion module, a second power conversion module and a bypass function circuit. The input end of the first power conversion module is connected with the energy-taking power supply. The output end of the first power conversion module is connected with the bypass function circuit. The input end of the second power conversion module is connected with the voltage division module. The output end of the second power conversion module is connected with the bypass function circuit. The bypass function circuit is connected with the first bypass module and the second bypass module. The bypass control assembly comprises a first power conversion module, a second power conversion module and a bypass function circuit. The input end of the first power conversion module is connected with the energy-taking power supply. The output end of the first power conversion module is connected with the bypass function circuit. The input end of the second power conversion module is connected with the voltage division module. The output end of the second power conversion module is connected with the bypass function circuit. The bypass function circuit is connected with the first bypass module and the second bypass module. The bypass control assembly comprises a first power conversion module, a second power conversion module and a bypass function circuit. The input end of the first power conversion module is connected with the energy-taking power supply. The output end of the first power conversion module is connected with the bypass function circuit. The input end of the second power conversion module is connected with the voltage division module. The output end of the second power conversion module is connected with the bypass function circuit. The bypass function circuit is connected with the first bypass module and the second bypass module. The bypass control assembly comprises a first power conversion module, a second power conversion module and a bypass function circuit. The input end of the first power conversion module is connected with the energy-taking power supply. The output end of the first power conversion module is connected with the bypass function circuit. The input end of the second power conversion module is connected with the voltage division module. The output end of the second power conversion module is connected with the bypass function circuit. The bypass function circuit is connected with the first bypass module and the second bypass module. The bypass control assembly comprises a first power conversion module, a second power conversion module and a bypass function circuit. The input end of the first power conversion module is connected with the energy-taking power supply. The output end of the first power conversion module is connected with the bypass function circuit. The input end of the second power conversion module is connected with the voltage division module. The output end of the second power conversion module is connected with the bypass function circuit. The bypass function circuit is connected with the first bypass module and the second bypass module. The bypass control assembly comprises a first power conversion module, a second power conversion module and a bypass function circuit. The input end of the first power conversion module is connected with the energy-taking power supply. The output end of the first power conversion module is connected with the bypass function circuit. The input end of the second power conversion module is connected with the voltage division module. The output end of the second power conversion module is connected with the bypass function circuit. The bypass function circuit is connected with the first bypass module and the second bypass module. The bypass control assembly comprises a first power conversion module, a second power conversion module and a bypass function circuit. The input end of the first power conversion module is connected with the energy-taking power supply. The output end of the first power conversion module is connected with the bypass function circuit. The input end of the second power conversion module is connected with the voltage division module. The output end of the second power conversion module is connected with the bypass function circuit. The bypass function circuit is connected with the first bypass module and the second bypass module. The bypass control assembly comprises a first power conversion module, a second power conversion module and a bypass function circuit. The input end of the first power conversion module is connected with the energy-taking power supply. The output end of the first power conversion module is connected with the bypass function circuit. The input end of the second power conversion module is connected with the voltage division module. The output end of the second power conversion module is connected with the bypass function circuit. The bypass function circuit is connected with the first bypass module and the second bypass module. The bypass control assembly comprises a first power conversion module, a second power conversion module and a bypass function circuit. The input end of the first power conversion module is connected with the energy-taking power supply. The output end of the first power conversion module is connected with the bypass function circuit. The input end of the second power conversion module is connected with the voltage division module. The output end of the second power conversion module is connected with the bypass function circuit. The bypass function circuit is connected with the first bypass module and the second bypass module. The bypass control assembly comprises a first power conversion module, a second power conversion module and a bypass function circuit. The input end of the first power conversion module is connected with the energy-taking power supply. The output end of the first power conversion module is connected with the bypass function circuit. The input end of the second power conversion module is connected with the voltage division module. The output end of the second power conversion module is connected with the bypass function circuit. The bypass function circuit is connected with the first bypass module and the second bypass module. The bypass control assembly comprises a first power conversion module, a second power conversion module and a bypass function circuit. The input end of the first power conversion module is connected with the energy-taking power supply. The output end of the first power conversion module is connected with the bypass function circuit. The input end of the second power conversion module is connected with the voltage division module. The output end of the second power conversion module is connected with the bypass function circuit. The bypass function circuit is connected with the first bypass module and the second bypass module. The bypass control assembly comprises a first power conversion module, a second power conversion module and a bypass function circuit. The input end of the first power conversion module is connected with the energy-taking power supply. The output end of the first The voltage dividing module is connected with the anode of the third diode, and the cathode of the third diode is connected with the bypass control component; The voltage dividing module is connected with the anode of the fourth diode, and the cathode of the fourth diode is connected with the second bypass module.

8. The apparatus of claim 7, wherein, The sub-module central control board is further included; the take-energy power supply and the bypass control component are respectively connected with the sub-module central control board.

9. The apparatus of claim 8, wherein, Further comprising: A fifth diode; The output end of the second power conversion module is connected with the anode of the fifth diode, and the cathode of the fifth diode is connected with the sub-module central control board.

10. A method of bypassing a LCC valve, characterized by The device is applied to any one of claims 1-9, comprising: The bypass control component outputs a driving signal to the first bypass module and the second bypass module in response to a bypass instruction, so that the first bypass module and the second bypass module close the bypass switch.

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