Protection device and method based on short-circuited resistor and converter valve power module

Abstract

The invention provides a protection device and method based on a short-circuited resistor and a converter valve power module, and belongs to the technical field of flexible direct-current power transmission. The protection device comprises a switch module and a short-circuited resistor, the switch module and the short-circuited resistor are connected in series; the switch module and the short-circuited resistor which are connected in series are connected in parallel with the power module through a direct current port of the converter valve power module, and a loop where the switch module and the short-circuited resistor are located serves as a bypass path of the power module; the switch module is used for controlling on and off of a bypass path through switch action; and the short-circuited resistor is used for carrying out energy consumption on the power module when the bypass path is opened so as to realize protection on the power module. According to the method, the reliable second bypass path can be provided when the bypass switch of the power module refuses to operate, meanwhile, the system cost is reduced, and the stability and economical efficiency of offshore wind power transmission are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of flexible direct current power transmission, and in particular relates to a protection device and method based on a short-circuit resistor and a converter valve power module. Background Art

[0002] With the rapid development of power transmission and distribution technology in my country, offshore UHV wind power transmission technology has become an important direction for the development of new energy. Offshore wind farms transmit electricity to land through flexible DC transmission systems, which have the advantages of long transmission distance, low loss and high reliability. However, the operating environment of offshore wind farms is complex and changeable, which puts higher requirements on the stability and reliability of the transmission system.

[0003] In the existing flexible DC transmission system, the flexible DC converter is its core component, which is responsible for converting AC power into DC power for transmission. In order to ensure the stable operation of the system and avoid wind farm tripping due to faults at the transmission or receiving end, some studies have proposed adding resistors and power electronic switches to the DC side of the power module of the flexible DC converter. This solution can solve the problem of system stability to a certain extent, but when the bypass switch (PS) of the power module refuses to operate, the system lacks a second bypass path to ensure that the power module is reliably removed from the flexible DC transmission system. This may cause the system to be unable to isolate the faulty module in time in the event of a fault, thereby affecting the safe operation of the entire system. At the same time, the cost of power electronic switches is high, and their large-scale use will increase the construction cost of the system, limiting its application in large-scale offshore wind power transmission projects. Summary of the invention

[0004] In view of this, the present invention aims to provide a protection device, method and converter valve power module based on a short-circuit resistor, which can provide a reliable second bypass path when the power module bypass switch fails to operate, while reducing system costs and improving the stability and economy of offshore wind power transmission.

[0005] In order to achieve the above object, the technical solution provided by the present invention is as follows:

[0006] In a first aspect, the present invention provides a protection device based on a short-circuit resistor, comprising:

[0007] Switching modules and short-circuitable resistors;

[0008] The switch module and the short-circuit resistor are connected in series;

[0009] The switch module and the short-circuit resistor connected in series are connected in parallel with the power module through the DC port of the converter valve power module, and the loop where the switch module and the short-circuit resistor are located serves as a bypass path of the power module;

[0010] The switch module is used to control the opening and closing of the bypass path through a switch action;

[0011] The short-circuit resistor is used to consume energy of the power module when the bypass path is opened, so as to protect the power module.

[0012] Furthermore, the switch module is connected to the DC positive terminal of the power module, and the short-circuit resistor is connected to the DC negative terminal of the power module.

[0013] Further, the switch module includes: a control component and an electronic switch execution component;

[0014] The control component is used to control the electronic switch execution component to execute a corresponding switching action, so as to open / close the bypass path when the voltage value of the power module exceeds / is lower than a set threshold.

[0015] Furthermore, the electronic switch actuator maintains a reliable closed state when power is off.

[0016] Furthermore, the material of the short-circuit resistor is a negative temperature coefficient resistor material, and the resistance of the short-circuit resistor decreases as the temperature increases until it decreases to zero.

[0017] Further, the short-circuit resistor is provided with: a coolant channel;

[0018] The coolant channel is used to pass the coolant to adjust the theoretical temperature range of the low resistance value interval of the short-circuit resistor.

[0019] In a second aspect, the present invention provides a protection method based on a short-circuit resistor, which is applied to a protection device based on a short-circuit resistor as in the first aspect, and the method comprises the following steps:

[0020] Real-time monitoring of the voltage value of the power module;

[0021] When the voltage value of the power module exceeds the set threshold, the switch module is made to perform an opening action so that the short-circuit resistor is put into operation and the power module is protected;

[0022] When the voltage value of the power module is lower than the set threshold, the switch module is made to perform a shut-down action so that the short-circuit resistor is removed, and the protection action of the converter valve submodule is completed.

[0023] In a third aspect, the present invention provides a converter valve power module, comprising:

[0024] Power modules and protection devices;

[0025] The protection device is connected in parallel with the power module through the DC port of the power module;

[0026] The protection device adopts the protection device based on a short-circuit resistor as in the first aspect.

[0027] Further, the power module includes: a first switch device, a second switch device, a first diode, a second diode and a capacitor;

[0028] The cathode terminal of the first switching device is connected to the anode terminal of the second switching device;

[0029] The first diode and the second diode are connected in anti-parallel with the first switching device and the second switching device respectively;

[0030] The positive electrode of the capacitor is connected to the positive terminal of the first switch device, and the negative electrode of the capacitor is connected to the negative terminal of the second switch device;

[0031] The common connection point between the capacitor and the two switching devices is the DC port of the power module;

[0032] The loop where the protection device and the first diode are located is a bypass path.

[0033] Furthermore, the power module further comprises: a bypass switch;

[0034] The bypass switch is connected in parallel with the second switch device;

[0035] The circuit where the bypass switch is located is the main bypass path;

[0036] The loop where the protection device and the first diode are located is a backup bypass path.

[0037] In summary, the present invention provides a protection device based on a short-circuit resistor, including a switch module and a short-circuit resistor; the switch module and the short-circuit resistor are connected in series; the switch module and the short-circuit resistor after the series connection are connected in parallel with the power module through the DC port of the converter valve power module, and the circuit where the switch module and the short-circuit resistor are located serves as a bypass path of the power module; the switch module is used to control the opening and closing of the bypass path through the switch action; the short-circuit resistor is used to consume energy of the power module when the bypass path is opened, so as to realize the protection of the power module. The device can provide a reliable second bypass path when the bypass switch of the power module refuses to operate, while reducing the system cost and improving the stability and economy of offshore wind power transmission.

[0038] The present invention also provides a corresponding protection method and a converter valve power module having the protection device. The method and module have the same effect as the above protection device when implemented, and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0040] Figure 1 A block diagram of a protection device based on a short-circuit resistor provided in an embodiment of the present invention;

[0041] Figure 2 A schematic diagram of the structure of a controllable electronic switch provided in an embodiment of the present invention;

[0042] Figure 3 A schematic diagram of the structure of a short-circuit resistor provided by an embodiment of the present invention;

[0043] Figure 4 A graph showing the relationship between resistance and temperature change of a short-circuit resistor provided in an embodiment of the present invention;

[0044] Figure 5 A schematic diagram of a bypass path of a converter valve power module provided in an embodiment of the present invention.

[0045] In the attached figure: 1-electronic switch actuator, 2-control component, 3-input and output terminals, 4-short-circuit resistor, 5-coolant inlet and outlet, 6-DC positive busbar, 7-DC negative busbar. DETAILED DESCRIPTION

[0046] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] In the existing flexible DC transmission system, the flexible DC converter is its core component, which is responsible for converting AC power into DC power for transmission. In order to ensure the stable operation of the system and avoid wind farm tripping due to faults at the transmission or receiving end, some studies have proposed adding resistors and power electronic switches to the DC side of the power module of the flexible DC converter. This solution can solve the problem of system stability to a certain extent, but when the bypass switch (PS) of the power module refuses to operate, the system lacks a second bypass path to ensure that the power module is reliably removed from the flexible DC transmission system. This may cause the system to be unable to isolate the faulty module in time in the event of a fault, thereby affecting the safe operation of the entire system. At the same time, the cost of power electronic switches is high, and their large-scale use will increase the construction cost of the system, limiting its application in large-scale offshore wind power transmission projects.

[0048] Therefore, the present invention provides a protection device, method and converter valve power module based on a short-circuit resistor.

[0049] An embodiment of a protection device based on a short-circuit resistor according to the present invention is introduced below.

[0050] See also Figure 1 An embodiment of the present invention provides a protection device based on a short-circuit resistor, comprising: a switch module and a short-circuit resistor; the switch module and the short-circuit resistor are connected in series; the series-connected switch module and the short-circuit resistor are connected in parallel with the power module through the DC port of the converter valve power module, and the circuit where the switch module and the short-circuit resistor are located serves as a bypass path of the power module; the switch module is used to control the opening and closing of the bypass path through a switch action; the short-circuit resistor is used to consume energy of the power module when the bypass path is opened, so as to protect the power module.

[0051] It should be noted that the main function of the switch module is to control the opening and closing of the bypass path through its own switching action. When a power module fault is detected, the module responds quickly and bypasses the faulty module to avoid affecting the entire system.

[0052] When the bypass path is opened, the short-circuit resistor consumes the energy of the power module. This is done to prevent the faulty module from continuing to interfere with the system and helps protect the power module from excessive voltage or current shocks, thereby extending its service life. By consuming energy through the short-circuit resistor, the risk of damage to the power module is reduced, thereby reducing maintenance frequency and cost.

[0053] The two modules are connected in series and then connected in parallel with the DC port of the converter valve power module as a whole, forming a new bypass path. When the original bypass switch (PS) fails, the new protection device can still provide a way to isolate the faulty module. The newly added bypass path can effectively deal with the failure of the original bypass switch and enhance the fault tolerance of the system.

[0054] This embodiment provides a protection device based on a short-circuit resistor, which can provide a reliable second bypass path when the power module bypass switch refuses to operate, while reducing system costs and improving the stability and economy of offshore wind power transmission.

[0055] In one embodiment, the switch module is connected to the DC positive terminal of the power module, and the short-circuit resistor is connected to the DC negative terminal of the power module.

[0056] It should be noted that when a bypass requirement is detected in a power module, the switch module will be triggered to open, and the current will flow through the bypass path formed by the switch module and the short-circuit resistor. The short-circuit resistor absorbs the energy of the current in this process, thereby preventing excessive energy from accumulating in the faulty module and protecting the power module from further damage.

[0057] In one embodiment, the switch module includes: a control component and an electronic switch execution component;

[0058] The control component is used to control the electronic switch execution component to execute a corresponding switching action, so as to open / close the bypass path when the voltage value of the power module exceeds / is lower than a set threshold.

[0059] It should be noted that the control component is the core part of the switch module, which is mainly responsible for monitoring the status of the power module and issuing instructions to the electronic switch execution component based on the monitoring results. Specifically, the functions of the control component include: (1) real-time monitoring or obtaining the voltage value at both ends of the power module to determine whether it exceeds the preset threshold. (2) When it is detected that the voltage value of the power module exceeds the set safety range (that is, higher or lower than the set threshold), the control component will make a decision and trigger the corresponding switch action. (3) Send a command signal to the electronic switch execution component to instruct it to open or close the operation.

[0060] The electronic switch actuator is the part that actually performs the switch operation. Its main function is to receive the command signal from the control component. According to the received command signal, it performs the opening or closing operation to control the state of the bypass path. The electronic switch actuator can also feedback its current state to the control component to help the control component better adjust and manage the bypass path.

[0061] In this embodiment, when the voltage value of the power module exceeds or falls below the set threshold, the control component detects this change and determines whether the bypass path needs to be activated according to the preset logic. If it is indeed necessary, the control component sends a corresponding signal to the electronic switch execution component. After receiving the signal, the electronic switch execution component performs an opening or closing action, thereby changing the state of the bypass path.

[0062] Based on the switch module designed in the aforementioned embodiment, in a further embodiment, the electronic switch actuator maintains a reliable closed state when the power is off.

[0063] See also Figure 2 , Figure 2 The external structure of a controllable electronic switch is shown, which is a design example of the switch module proposed in this embodiment. The controllable electronic switch S is divided into three parts: a controllable electronic switch execution component 1, a control component 2 and an input and output terminal 3. The controllable electronic switch S is connected to other components through the input and output terminals 3. A control board is arranged inside the control component 2, which can receive the voltage of the power module capacitor C and the state of the controllable electronic switch execution component 1 in real time. The control component 2 can monitor the voltage and temperature changes in real time, and the voltage threshold is preset by the control component 2. The electronic switch S can be a mechanical electronic switch, which can remain reliably closed after power failure. When the power module is bypassed from the converter circuit, the charge stored in the capacitor C will be consumed, and the control component 2 of the controllable electronic switch S will not work normally. However, at this time, the electronic switch S has been stably closed and can achieve long-term reliable bypass with the short-circuit resistor, ensuring that the power module can be isolated from the converter stably for a long time. At the same time, when the power module fault is restored or when the voltage reaches the lower limit of the threshold value for a period of time, the control component 2 can issue a disconnection command to the electronic switch execution component 1 when it is powered and can work, so that the electronic switch S is automatically disconnected, thereby disconnecting the bypass path and the short-circuit resistor stops consuming energy.

[0064] In one embodiment, the material of the short-circuit resistor is a negative temperature coefficient resistor material, and the resistance of the short-circuit resistor decreases as the temperature increases until it decreases to zero.

[0065] In this embodiment, the short-circuit resistor uses a negative temperature coefficient (NTC) resistor material. The characteristic of this material is that the resistance value decreases when the temperature rises until it decreases to near zero. NTC resistor material is a semiconductor material whose resistivity decreases significantly with increasing temperature. This is because as the temperature rises, the number of carriers (free electrons and holes) inside the semiconductor increases, the conductivity is enhanced, and thus the resistance decreases. When the temperature reaches a certain level, the resistance becomes almost zero. The main function of using NTC resistor material in the short-circuit resistor is to adjust the resistance value through temperature changes when the power module fails and needs to be bypassed, thereby consuming excess energy in the faulty module.

[0066] When the short-circuit resistor is working, as the current passes through the short-circuit resistor, the NTC resistor begins to heat up and the temperature gradually rises. As the temperature rises, the resistance value of the NTC resistor begins to decrease, and the current is easier to pass. When the temperature reaches a certain level, the resistance value of the NTC resistor is close to zero, which is equivalent to a short-circuit state. At this time, the short-circuit resistor can quickly consume the excess power in the power module to prevent excessive voltage or current from damaging other equipment.

[0067] The short-circuit resistor of this embodiment is particularly suitable for occasions that require rapid response and protection of power modules from overvoltage or overcurrent. In a flexible DC power transmission system, when a power module fails, the characteristics of the NTC resistor material can quickly bypass the faulty module and consume excess energy to ensure stable operation of the system.

[0068] Based on the short-circuit resistor of the foregoing embodiment, in a further embodiment, the short-circuit resistor is provided with: a coolant channel; the coolant channel is used to pass coolant to adjust the theoretical temperature range of the low resistance interval of the short-circuit resistor.

[0069] In this embodiment, the theoretical temperature range of the low resistance interval of the resistor refers to the temperature interval in which the NTC resistor material exhibits a lower resistance value within a certain temperature range in the short-circuit resistor. The main function of the coolant channel is to adjust the temperature of the short-circuit resistor by passing the coolant. When the short-circuit resistor begins to consume energy, the NTC resistor material will heat up, causing the resistance value to drop. By introducing the coolant, the temperature of the NTC resistor material can be controlled to keep it within a certain range, thereby adjusting its resistance value.

[0070] For example, in order to maintain the NTC resistor material in a suitable low resistance range, coolant can be introduced into the coolant channel to take away excess heat and enable the short-circuit resistor to consume more energy. By dynamically adjusting the flow of coolant, the temperature of the short-circuit resistor can be kept at a stable level, thereby ensuring that the resistance value is within the low resistance range and quickly consuming excess energy in the power module.

[0071] The short-circuit resistor of this embodiment is particularly suitable for occasions requiring high-precision energy management and rapid response by designing a cooling liquid channel. In a flexible DC power transmission system, when a power module fails, the short-circuit resistor can respond quickly, and adjust the resistance value through the cooling liquid to ensure that the faulty module can be isolated in a timely and effective manner, and the excess energy can be quickly consumed to ensure the stable operation of the system.

[0072] See also Figure 3 , Figure 3 FIG. 4 shows the external structure of a short-circuit resistor, which is a design example of a short-circuit resistor of this embodiment. The temperature and resistance change curve of the short-circuit resistor 4 is as shown in FIG. Figure 4 As shown. Its appearance is flat, and a coolant inlet and outlet 5 is reserved on the outside, which is convenient for installation and heat dissipation, and can also accurately design the theoretical temperature range of the low resistance range of the resistor. The short-circuit resistor 4 is provided with connecting terminals on both sides, and can also be crimped to the DC negative busbar of the power module and one end of the electronic switch S respectively.

[0073] The present invention further provides a protection method based on a short-circuit resistor, which is applied to a protection device based on a short-circuit resistor as in the above embodiment, and the method comprises the following steps:

[0074] S1: Real-time monitoring of the voltage value of the power module;

[0075] S2: When the voltage value of the power module exceeds the set threshold, the switch module is turned on to enable the short-circuit resistor to be put into operation and protect the power module;

[0076] S3: When the voltage value of the power module is lower than the set threshold, the switch module is ordered to perform a shutdown action so that the short-circuit resistor is removed, and the protection action of the converter valve submodule is completed.

[0077] In this embodiment, by monitoring the voltage value in real time and activating the bypass path when necessary, the faulty module can be quickly isolated to prevent the fault from spreading, thereby improving the stability of the entire system.

[0078] The present invention also provides a converter valve power module, comprising: a power module and a protection device; the protection device is connected in parallel with the power module through the DC port of the power module; the protection device adopts the protection device based on a short-circuit resistor as in the above-mentioned embodiment.

[0079] It should be noted that the power module is the core component of the converter valve, responsible for converting AC to DC or DC to AC. In a flexible DC transmission system, the power module is usually composed of multiple power units (such as power electronic devices such as IGBT) to achieve the conversion and transmission of electric energy. The protection device is connected in parallel with the power module through the DC port of the power module. When the power module is in normal working state, the protection device does not participate in the transmission path of electric energy. Only when a fault is detected will the protection device be activated to protect the power module from damage.

[0080] In one embodiment, the power module includes: a first switching device, a second switching device, a first diode, a second diode and a capacitor; the cathode port of the first switching device is connected to the anode port of the second switching device; the first diode and the second diode are respectively connected in anti-parallel with the first switching device and the second switching device; the anode of the capacitor is connected to the anode port of the first switching device, and the cathode of the capacitor is connected to the cathode port of the second switching device; the common connection point between the capacitor and the two switching devices is the DC port of the power module; the loop where the protection device and the first diode are located is a bypass path.

[0081] In this embodiment, the loop in which the protection device and the first diode are located constitutes a bypass path. When the protection device is activated, the current will flow through the loop formed by the protection device and the first diode instead of through the main circuit of the power module.

[0082] In one embodiment, the power module further includes: a bypass switch; the bypass switch is connected in parallel with the second switch device; the loop where the bypass switch is located is a main bypass path; the loop where the protection device and the first diode are located is a backup bypass path.

[0083] See also Figure 5 , Figure 5 The bypass path of the power module is shown. In the figure, after the short-circuit resistor R is connected in series with the controllable electronic switch S, it is connected to the power module through the DC positive busbar 6 and the DC negative busbar 7. When the voltage is too high due to a bypass failure such as a bypass refusal in the power module, the short-circuit resistor R can form a bypass current path or a backup bypass path through the diode D1, the short-circuit resistor R and the controllable electronic switch S. The bypass path is shown by the arrow in the figure.

[0084] Based on the controllable electronic switch S and the short-circuit resistor R proposed in the above example, the basic working principle in the power module is: when the bypass switch PS fails to operate or other abnormal faults occur in the power module, and the voltage of the capacitor C reaches the upper limit of the voltage threshold, the control component 2 issues a closing command to the electronic switch execution component 1 to realize the automatic closing action of the controllable electronic switch S, and the short-circuit resistor R and the closed controllable electronic switch S form a bypass current path or a backup bypass path through the diode D1, so that the above bypass path is formed as follows: Figure 5 As shown by the arrow, the short-circuit resistor R is then put into the module loop to consume energy, converting electrical energy into resistor heat energy, and the resistor temperature gradually increases; as the controllable electronic switch S is put into use for a longer and longer time, the capacitor voltage C significantly decreases, and the resistor R consumes more and more energy, so that the temperature rises sharply to T0. After the energy consumed by the short-circuit resistor R reaches the upper limit of the preset value, the temperature rises accordingly, and the resistance decreases accordingly. When the resistor temperature rises to T0, the resistance drops to nearly 0Ω. At this time, it can be regarded as a wire, isolating the entire module from the converter, and the electronic components inside the short-circuit resistor can be short-circuited, thereby forming a long-term stable bypass path, and the bypass path can be maintained for a long time even if the control component 2 is out of power.

[0085] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A protection device based on a short-circuit resistor, characterized in that: include: Switching modules and short-circuitable resistors; The switch module and the short-circuit resistor are connected in series; The switch module and the short-circuit resistor connected in series are connected in parallel with the power module through the DC port of the converter valve power module, and the loop where the switch module and the short-circuit resistor are located serves as a bypass path of the power module; The switch module is used to control the opening and closing of the bypass path through a switch action; The short-circuit resistor is used to consume energy of the power module when the bypass path is opened, so as to protect the power module.

2. The protection device based on a short-circuit resistor according to claim 1, characterized in that: The switch module is connected to the DC positive terminal of the power module, and the short-circuit resistor is connected to the DC negative terminal of the power module.

3. The protection device based on a short-circuit resistor according to claim 1, characterized in that: The switch module includes: a control component and an electronic switch execution component; The control component is used to control the electronic switch execution component to execute the corresponding switching action, so as to open / close the bypass path when the voltage value of the power module exceeds / is lower than a set threshold.

4. The protection device based on a short-circuit resistor according to claim 3, characterized in that: The electronic switch actuator maintains a reliable closed state when power is off.

5. The protection device based on a short-circuit resistor according to claim 1, characterized in that: The material of the short-circuit resistor is a negative temperature coefficient resistor material, and the resistance of the short-circuit resistor decreases as the temperature increases until it decreases to zero.

6. The protection device based on a short-circuit resistor according to claim 5, characterized in that: The short-circuit resistor is provided with: a coolant channel; The coolant channel is used to pass coolant to adjust the theoretical temperature range of the low resistance interval of the short-circuit resistor.

7. A protection method based on a short-circuit resistor, characterized in that: Applied to the protection device based on a short-circuit resistor as claimed in any one of claims 1 to 6, the method comprises the following steps: Real-time monitoring of the voltage value of the power module; When the voltage value of the power module exceeds a set threshold, the switch module is made to perform an opening action so that the short-circuit resistor is put into operation and the power module is protected; When the voltage value of the power module is lower than the set threshold, the switch module is made to perform a shut-down action so that the short-circuit resistor is cut off, and the protection action of the converter valve submodule is completed.

8. A converter valve power module, characterized in that: include: Power modules and protection devices; The protection device is connected in parallel with the power module through the DC port of the power module; The protection device adopts the protection device based on a short-circuit resistor as described in any one of claims 1-6.

9. The converter valve power module according to claim 8, characterized in that: The power module comprises: a first switch device, a second switch device, a first diode, a second diode and a capacitor; The cathode port of the first switching device is connected to the anode port of the second switching device; The first diode and the second diode are connected in anti-parallel with the first switching device and the second switching device respectively; The positive electrode of the capacitor is connected to the positive terminal of the first switch device, and the negative electrode of the capacitor is connected to the negative terminal of the second switch device; The common connection point between the capacitor and the two switch devices is the DC port of the power module; The loop where the protection device and the first diode are located is a bypass path.

10. The converter valve power module according to claim 9, characterized in that: The power module further includes: a bypass switch; The bypass switch is connected in parallel with the second switch device; The loop where the bypass switch is located is the main bypass path; The loop where the protection device and the first diode are located is a backup bypass path.

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