Quick bypass device for power module and power module

Abstract

The invention provides a quick bypass device for a power module and the power module, and belongs to the field of power electronics. The rapid bypass device comprises a discharging gap capable of being triggered, a bypass switch, a two-way redundancy triggering system and a control system. The discharge gap is connected in parallel with the bypass switch, and the on-state physical impedance of the discharge gap is higher than the on-state physical impedance of the bypass switch; the double-path redundancy triggering system comprises two paths of physically isolated triggering loops; the control system is used for injecting a trigger signal into the discharge gap through two trigger loops of the two-way redundancy trigger system, and is also used for issuing a bypass instruction to the bypass switch; the injection time of the trigger signal is earlier than the issuing time of the bypass instruction, and the time difference is within 10 microseconds to 20 microseconds; the discharge gap is used for forming an access when receiving a trigger signal; the bypass switch is used for being closed when receiving a bypass instruction. According to the invention, rapid, reliable, low-cost and reusable bypass protection of the power module can be realized.

Description

Technical Field

[0001] This invention belongs to the field of power electronics technology, specifically relating to a fast bypass device for a power module and a power module. Background Technology

[0002] Power electronics technology is widely used in many fields such as modern power systems and industrial production. Its core lies in achieving efficient conversion and control of electrical energy. As a key piece of equipment, power electronic power conversion devices can convert one form of electrical energy into a form that meets different needs.

[0003] In power electronic power conversion devices, half-bridge or full-bridge power modules play a core supporting role, and they are cascaded to construct the entire device. During actual operation, power modules may fail due to various complex factors.

[0004] In the event of a power module failure, it must be bypassed quickly to ensure safe operation of the equipment. Among existing bypass devices, thyristors can achieve rapid bypass, but they are expensive and can only be used once, after which they are damaged and need to be replaced, resulting in high operating costs and cumbersome operation. While fast bypass switches are low-cost and reusable, their bypass speed is slow and cannot meet the requirement of timely bypass. Summary of the Invention

[0005] In view of this, the present invention provides a fast bypass device and a power module for a power module, which is designed to enable fast bypass of the power module within an acceptable time, while avoiding the use of costly thyristors and slow bypass switches, thereby solving the above-mentioned shortcomings of existing bypass devices.

[0006] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0007] In a first aspect, the present invention provides a fast bypass device for a power module, comprising:

[0008] Triggerable discharge gap, bypass switch, dual-redundant triggering system and control system;

[0009] The discharge gap is connected in parallel with the bypass switch, and the on-state physical impedance of the discharge gap is higher than the on-state physical impedance of the bypass switch.

[0010] The dual-redundant triggering system includes two physically isolated triggering circuits;

[0011] The control system is used to inject trigger signals into the discharge gap through the two trigger circuits of the dual-redundant trigger system, and is also used to issue bypass commands to the bypass switch; the injection time of the trigger signal is earlier than the issuance time of the bypass command, and the time difference is within 10μs~20μs.

[0012] The discharge gap is used to create a path when a trigger signal is received;

[0013] The bypass switch is used to close when a bypass command is received.

[0014] Furthermore, the discharge gap is sealed within a closed cavity, and the bypass switch is independently located outside the closed cavity or placed together with the discharge gap within the closed cavity;

[0015] The interior of the sealed cavity is either a vacuum environment or filled with insulating gas, such as sulfur hexafluoride, nitrogen, or a mixture of nitrogen and carbon dioxide.

[0016] Furthermore, the dual-redundant triggering system includes: a local triggering loop and a cross-triggering loop between adjacent modules;

[0017] Both the local triggering circuit and the cross-triggering circuit of adjacent modules adopt an independent power supply mode;

[0018] The local triggering circuit is integrated inside the protected power module to directly receive the local triggering signal sent by the control system and forward it to the discharge gap;

[0019] The trigger control unit of the adjacent module cross triggering circuit is integrated inside the adjacent power module cascaded with the protected power module. A signal path is set between the trigger control unit and the discharge gap of the protected power module. The adjacent module cross triggering circuit is used to receive the cross trigger signal issued by the control system through the trigger control unit and forward it to the discharge gap.

[0020] Furthermore, the discharge gap includes one or more pairs of high-voltage electrodes and ground electrodes arranged opposite to each other. The high-voltage electrodes are connected to the high-voltage end of the protected power module, and the ground electrodes are connected to the low-voltage end of the protected power module.

[0021] Furthermore, at least two independent trigger cavities are embedded inside the ground electrode;

[0022] Each independent trigger chamber is equipped with an independent trigger electrode, which is electrically connected to each trigger circuit of the dual-redundant trigger system.

[0023] Furthermore, it also includes: an online monitoring and feedback module for the closed state;

[0024] The closed-state online monitoring feedback module includes a local feedback loop and a cross-feedback loop between adjacent modules;

[0025] The local feedback loop is integrated inside the protected power module and is used to directly acquire the conduction status signal of the discharge gap and the mechanical closing signal of the bypass switch;

[0026] The signal acquisition unit of the adjacent module cross feedback loop is integrated inside the adjacent power module cascaded with the protected power module. The adjacent module cross feedback loop is used to indirectly acquire the conduction status signal of the discharge gap and the mechanical closing signal of the bypass switch through the signal acquisition unit.

[0027] The local feedback loop and the adjacent module cross-feedback loop are based on a competition hazard verification mechanism, which feeds back the conduction status signal of the discharge gap and the mechanical closing signal of the bypass switch to the control system.

[0028] Furthermore, the power modules are cascaded power modules within the converter.

[0029] Furthermore, the converter adopts the following topologies: MMC half-bridge topology, MMC full-bridge topology, M3C full-bridge topology, or conventional cascaded full-bridge topology.

[0030] Furthermore, the converter is connected to the power frequency grid, low frequency grid, or motor.

[0031] Secondly, the present invention provides a power module, comprising:

[0032] Power unit, and fast bypass device for power module as in the first aspect;

[0033] The fast bypass device is connected in parallel with the capacitor in the power unit, or in parallel with the two output terminals of the power unit.

[0034] In summary, this invention provides a fast bypass device and a power module for a power module. The fast bypass device includes a triggerable discharge gap, a bypass switch, a dual-redundant triggering system, and a control system. The discharge gap and the bypass switch are connected in parallel, and the on-state physical impedance of the discharge gap is higher than that of the bypass switch. The dual-redundant triggering system includes two physically isolated triggering circuits. The control system is used to inject a trigger signal into the discharge gap through the two triggering circuits of the dual-redundant triggering system, and also to issue a bypass command to the bypass switch. The injection time of the trigger signal is earlier than the issuance time of the bypass command, and the time difference is within 10μs to 20μs. The discharge gap is used to form a path when the trigger signal is received. The bypass switch is used to close when the bypass command is received. This invention connects a triggerable discharge gap in parallel with a bypass switch, configures a dual-redundant triggering system and a 10μs~20μs timing coordinated control, and utilizes the difference in on-state physical impedance between the two to achieve natural transfer of fault current. This avoids the disadvantages of high cost and single-use of thyristors, and solves the problem of insufficient speed of a single fast bypass switch, thus achieving fast, reliable, low-cost and reusable bypass protection for power modules. Attached Figure Description

[0035] 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.

[0036] Figure 1 A block diagram of a fast bypass device for a power module provided in an embodiment of the present invention;

[0037] Figure 2 A schematic diagram showing the arrangement of the discharge gap and bypass switch provided in an embodiment of the present invention;

[0038] Figure 3 A wiring diagram of a fast bypass device for a power module connected in parallel across a power unit capacitor, provided as an embodiment of the present invention;

[0039] Figure 4 This is a wiring diagram of a fast bypass device for a power module connected in parallel to two output terminals of a power unit, provided as an embodiment of the present invention.

[0040] In the attached diagram: 1 - first closed cavity, 2 - second closed cavity. Detailed Implementation

[0041] 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. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0042] The following section first introduces some of the technical terms used in the prior art involved in this invention:

[0043] (1) Power Module: In the field of power electronics, a power module is a functional unit that integrates multiple power electronic devices (such as diodes, thyristors, transistors, etc.) and their related drive circuits and protection circuits into a single package. It can realize the conversion and control of electrical energy, such as converting DC to AC (inverter) or AC to DC (rectifier), as well as regulating voltage and current. It is a core component of various power electronic devices (such as frequency converters, inverters, switching power supplies, etc.). In high-voltage power electronic power conversion devices, multiple power modules are usually cascaded to meet the requirements of high-voltage and high-power electrical energy conversion.

[0044] (2) Thyristor: Also known as a crystal thyristor, it is a high-power semiconductor device with a four-layer PNPN structure and belongs to the category of power electronic devices. It has unidirectional conductivity, and its conduction state can be triggered by a signal at the control electrode (also known as the gate). In a circuit, when the anode of the thyristor is subjected to a positive voltage and an appropriate trigger signal is applied to the control electrode, the thyristor will conduct, and the current will flow from the anode to the cathode. The main characteristics of the thyristor are that it can withstand high voltage and large current, and it is often used in power electronic circuits such as controlled rectification, AC voltage regulation, and contactless electronic switches. However, as mentioned above, although it has a fast conduction speed (turn-on time within 10μs) when used for power module bypass, it is expensive and usually used only once. Once it is triggered to conduct under a large current, it will be damaged and needs to be replaced.

[0045] (3) Fast bypass switch: This is a switching device used in power systems to quickly bypass faulty equipment (such as power modules) from the circuit, allowing the system to continue operating normally. Its design aims to achieve rapid circuit switching to protect other normally operating equipment from the impact of the fault. Generally, fast bypass switches operate faster than traditional switches, but compared to thyristors, their bypass speed is typically around 3ms, which is relatively slow. However, it has the advantages of low cost and reusability.

[0046] (4) Half-bridge power module: This is a common topology for power modules. It consists of two power electronic switching devices (such as transistors) and related diodes, connected in a half-bridge configuration. In the circuit, these two switching devices alternately turn on and off, enabling basic energy conversion, such as converting direct current into a portion of an alternating current signal with a certain frequency (therefore, it is often used as the basic unit for building a complete inverter circuit). Multiple half-bridge power modules can be cascaded to meet the application requirements of higher voltage and power.

[0047] (5) Full-bridge power module: This is also a common power module topology. It consists of four power electronic switching devices (such as transistors) and related diodes, connected in a full-bridge configuration. Full-bridge power modules can achieve more complete power conversion functions than half-bridge power modules. For example, they can convert direct current into alternating positive and negative alternating current signals. They are commonly used in various power electronic devices, such as inverters and DC-DC converters, to achieve efficient power conversion and control. Compared to half-bridge power modules, full-bridge power modules have different characteristics and application scenarios in terms of power and voltage levels.

[0048] (6) MMC Half-Bridge Topology: This refers to the Modular Multilevel Converter (MMC) half-bridge topology. MMC is a novel multilevel voltage source converter topology with advantages such as low output harmonic content, low switching frequency, and easy modular expansion. The MMC half-bridge topology is a basic unit form in the MMC structure. Each MMC half-bridge module consists of two switching devices and one capacitor. Multiple such half-bridge modules are cascaded to form one phase of the converter. It has wide applications in flexible DC transmission, high-voltage DC transmission, and other fields, enabling efficient and flexible power conversion and transmission.

[0049] (7) MMC Full-Bridge Topology: Also based on the modular multilevel converter structure, each module of the MMC full-bridge topology consists of four switching devices and one capacitor. Compared with the MMC half-bridge topology, the full-bridge topology has certain advantages in terms of fault ride-through capability and output waveform quality. In some application scenarios with high requirements for power quality and system reliability, the MMC full-bridge topology can better meet the needs, such as in the fields of new energy grid access and flexible interconnection of urban power grids, where it has important application value.

[0050] (8) M3C Full-Bridge Topology: The Modular Multilevel Matrix Converter (M3C) full-bridge topology is a topology suitable for multi-terminal DC transmission systems. It is an improvement and extension of the traditional full-bridge topology to meet the needs of flexible power transmission and distribution between multiple DC terminals. The M3C full-bridge topology can realize efficient connection and power conversion between DC terminals with different voltage levels and power requirements, and has unique advantages in building complex DC transmission networks, especially in scenarios involving multiple power sources and loads.

[0051] (9) Conventional Cascaded Full-Bridge Topology: This refers to a topology formed by connecting (cascading) multiple full-bridge power modules sequentially in a certain manner. In this topology, the output voltages of each full-bridge module are superimposed, thereby achieving a higher output voltage level to meet the needs of high-voltage, high-power power systems. Conventional cascaded full-bridge topologies are widely used in power electronic devices such as high-voltage static var compensators and high-voltage frequency converters. By rationally controlling the switching actions of each cascaded full-bridge module, precise control of output voltage and current can be achieved, improving the power quality and operational stability of the system.

[0052] Please see Figure 1 The present invention provides a fast bypass device for a power module, the fast bypass device comprising:

[0053] Triggerable discharge gap, bypass switch, dual-redundant triggering system and control system;

[0054] The discharge gap is connected in parallel with the bypass switch, and the on-state physical impedance of the discharge gap is higher than the on-state physical impedance of the bypass switch.

[0055] The dual-redundant triggering system includes two physically isolated triggering circuits;

[0056] The control system is used to inject trigger signals into the discharge gap through the two trigger circuits of the dual-redundant trigger system, and is also used to issue bypass commands to the bypass switch; the injection time of the trigger signal is earlier than the issuance time of the bypass command, and the time difference is within 10μs~20μs.

[0057] The discharge gap is used to create a path when a trigger signal is received;

[0058] The bypass switch is used to close when a bypass command is received.

[0059] It should be noted that the triggerable discharge gap achieves active conduction based on the principle of gas discharge or vacuum discharge. It consists of two oppositely arranged electrodes and an insulating medium filling the space between the electrodes. Under the action of an external trigger signal, the dielectric state can be broken to form a conductive path. The conduction response speed is in the ns~μs range. It does not require a continuous drive signal to maintain the conduction state. After triggering, it can rely on the fault current of the main circuit to maintain the path. Its on-state physical impedance characteristic is designed to be higher than that of the bypass switch. In power electronic systems, it mainly undertakes the function of rapid pre-conduction when a fault occurs. At the same time, it has a strong surge current tolerance capability and can withstand the impact of short-term large fault current without damage.

[0060] Bypass switches are low-impedance current-carrying devices suitable for medium and high voltage power electronic systems. Their function is to provide long-term reliable bypassing of the faulty module in the event of a power module failure. Their on-state physical impedance is typically in the mΩ range, possessing a current-carrying capacity matching the rated current of the MMC submodule, and a closing response speed meeting μs-level operation requirements. Power electronic switching devices such as IGBT modules, SCR thyristors, or integrated gate commutated thyristors (IGCTs) can be selected. They can quickly close to form a low-impedance path after receiving a bypass command, carrying the main circuit current after pre-conduction during the discharge gap. They must withstand the short-time transition current during the current transfer process from the discharge gap, possessing a corresponding current tolerance margin to ensure operational stability.

[0061] The dual-redundant triggering system is a dual-backup drive unit that provides trigger signals for triggerable discharge gaps. It consists of two independent triggering circuits. The two triggering circuits can be physically isolated using optocoupler isolation, magnetic isolation, or capacitive isolation. This prevents electromagnetic interference from one circuit from affecting the other and also prevents high voltage from the main circuit from entering the control circuit and causing safety hazards. Both circuits have functional redundancy; if either circuit is functioning normally, it can output a signal to the discharge gap that meets the trigger threshold requirements. The output signal is typically a high-voltage pulse or a high-current pulse, and the transmission delay of the two signals is consistent, ensuring synchronous breakdown and conduction of the electrodes at both ends of the discharge gap. In MMC systems, this improves the reliability of discharge gap triggering and prevents the discharge gap from failing to conduct due to a single triggering circuit failure.

[0062] As the core decision-making and execution unit of the fast bypass device, the control system integrates fault detection signal interface, trigger timing control, and switch drive command generation functions. It is usually built using FPGA, DSP, or dedicated logic chip, and has μs-level timing control accuracy. It can receive fault detection signals from the power module in real time, including IGBT open / short circuit signals, capacitor overvoltage signals, and temperature over-limit signals. After detecting a fault signal, it initiates the bypass process. First, it outputs a trigger command to the dual-redundant trigger system. The trigger signal is injected into the discharge gap through two physically isolated trigger circuits. Then, after a preset delay, a bypass command is sent to the bypass switch. The difference between the trigger signal injection time and the bypass command issuance time is controlled within the range of 10μs to 20μs. The total delay from receiving the fault detection signal to the command output is controlled at the μs level to match the fault ride-through response requirements of the power electronic system.

[0063] This embodiment provides a fast bypass device for power modules. The working principle of the device is that after the control system detects a fault signal, it first triggers the discharge gap to conduct rapidly through a dual-path physically isolated redundant triggering system, and then sends a closing command to the low-impedance bypass switch after a delay of 10μs~20μs, so that the main circuit current is smoothly transferred from the discharge gap to the bypass switch, thereby achieving reliable isolation of the faulty module. The device adopts a collaborative design of discharge gap pre-conduction and bypass switch delayed closing, combined with a dual-path redundant triggering system to improve triggering reliability. Through differential matching of on-state impedance and precise timing control, it achieves μs-level fast bypass while avoiding hard switching losses of the bypass switch, thus balancing response speed, operational reliability and low on-state loss.

[0064] In one embodiment of the present invention, the discharge gap is sealed in a closed cavity, and the bypass switch is independently disposed outside the closed cavity or placed together with the discharge gap in the closed cavity;

[0065] The interior of the sealed cavity is either a vacuum environment or filled with insulating gas, such as sulfur hexafluoride, nitrogen, or a mixture of nitrogen and carbon dioxide.

[0066] Please see Figure 2 The figure illustrates the arrangement of a discharge gap and bypass switch in a fast bypass device, which includes a trigger signal F, a discharge gap G, and a bypass switch K (the control system and dual-redundant trigger system are omitted here). The discharge gap G is hermetically sealed inside a first enclosed cavity 1 or a second enclosed cavity 2. The bypass switch K can be independently located outside the enclosed cavity (e.g., the second enclosed cavity 2) or placed together with the discharge gap G in the same enclosed cavity (e.g., the first enclosed cavity 1). Simultaneously, the internal environment of these enclosed cavities is configured as a vacuum or filled with an insulating gas (specifically, sulfur hexafluoride, nitrogen, or a mixture of nitrogen and carbon dioxide). This environmental configuration provides suitable insulation conditions to the discharge gap G, thereby ensuring the stability and reliability of its triggering and conduction process.

[0067] When the power module is functioning normally, the discharge gap G is insulated and the bypass switch K is open. When the power module malfunctions, the trigger signal F first triggers the discharge gap G, causing it to discharge under voltage. After triggering the discharge gap G, the triggering device F sends a closing signal to the bypass switch K after a delay of 10μs to 20μs, causing the bypass switch K to close quickly. After closing, the voltage across the discharge gap G drops to zero, extinguishing the arc and allowing all current to flow through the bypass switch K, preventing the arc in the discharge gap G from burning for an extended period.

[0068] In one embodiment of the present invention, the dual-redundant triggering system includes: a local triggering circuit and a cross-triggering circuit of adjacent modules;

[0069] Both the local triggering circuit and the cross-triggering circuit of adjacent modules adopt an independent power supply mode;

[0070] The local triggering circuit is integrated inside the protected power module to directly receive the local triggering signal sent by the control system and forward it to the discharge gap;

[0071] The trigger control unit of the adjacent module cross triggering circuit is integrated inside the adjacent power module cascaded with the protected power module. A signal path is set between the trigger control unit and the discharge gap of the protected power module. The adjacent module cross triggering circuit is used to receive the cross trigger signal issued by the control system through the trigger control unit and forward it to the discharge gap.

[0072] In this embodiment, the two trigger circuits are powered independently to avoid common-cause power supply failures. When the protected power module needs to trigger bypass, the control system simultaneously sends a local trigger signal to the local trigger circuit integrated within the protected module and a cross-trigger signal to the cross-trigger circuit trigger control unit in the cascaded adjacent modules. The local trigger circuit directly forwards the signal to the discharge gap of the protected module, while the trigger control unit in the adjacent module transmits the cross-trigger signal to the discharge gap through a signal path. The two circuits work in parallel, and trigger signal injection can be completed as long as either signal transmission is normal. This embodiment improves trigger reliability through redundant design and distributed deployment: independent power supply avoids the risk of simultaneous failure of both circuits due to a single power supply failure; the local circuit ensures efficient triggering under normal operating conditions; and the cross-trigger circuit deployed in adjacent modules avoids the single-point risk of failure of the local circuit due to a fault in the protected module itself. Ultimately, this ensures that the discharge gap stably receives the trigger signal and prevents the power module failure from spreading to the entire power electronic system.

[0073] In one embodiment of the present invention, the discharge gap includes one or more pairs of high-voltage electrodes and ground electrodes arranged opposite to each other. The high-voltage electrodes are connected to the high-voltage end of the protected power module, and the ground electrodes are connected to the low-voltage end of the protected power module.

[0074] It should be noted that the discharge gap is formed by one or more pairs of oppositely arranged high-voltage electrodes and ground electrodes. The high-voltage electrodes are electrically connected to the high-voltage end of the protected power module, and the ground electrodes are connected to its low-voltage end. When the power module is operating normally, the insulating medium between the electrodes remains open. When the protected power module fails, the voltage difference between the high-voltage end and the low-voltage end of the module is applied between the high-voltage electrode and the ground electrode. With the trigger signal input from the dual-redundant trigger system, the insulating medium between the electrodes is ionized and broken down, forming a conductive path from the high-voltage end to the low-voltage end of the power module.

[0075] The configuration of one or more pairs of electrodes in this embodiment can be adapted to power modules with different voltage levels and fault current capacities (multiple pairs of electrodes can improve the current carrying capacity of the discharge gap); and the corresponding connection between the electrodes and the high and low voltage terminals of the power module can directly clamp the high and low voltage terminals of the protected module, quickly eliminate the voltage difference between the two ends of the module, provide a temporary discharge path for the fault current, and prevent the fault current from continuously impacting the power module.

[0076] In one embodiment of the present invention, at least two independent trigger cavities are embedded inside the ground electrode;

[0077] Each independent trigger chamber is equipped with an independent trigger electrode, which is electrically connected to each trigger circuit of the dual-redundant trigger system.

[0078] It should be noted that at least two isolated independent trigger cavities are embedded inside the ground electrode. Each trigger cavity is equipped with a corresponding independent trigger electrode, and each independent trigger electrode is electrically connected to a different trigger circuit of the dual-redundant trigger system. When the dual-redundant trigger system outputs a trigger signal, the signal of each trigger circuit is transmitted to its matched independent trigger electrode, causing the medium inside the corresponding trigger cavity to be ionized and broken down first, thereby triggering the complete breakdown of the medium between the high-voltage electrode and the ground electrode in the entire discharge gap, thus completing the path construction.

[0079] This embodiment achieves one-to-one redundant matching between the trigger circuit and the trigger electrode through the design of independent trigger chambers and trigger electrodes, avoiding the single-point risk that the entire discharge gap cannot be triggered due to a single trigger chamber / trigger electrode failure. This design forms a trigger redundancy mechanism linked with the dual-path redundant trigger system, ensuring that when any trigger circuit is normal, the dielectric breakdown can be completed through the corresponding independent trigger chamber, further improving the reliability of discharge gap triggering and ensuring the stable realization of the pre-conduction stage of the fast bypass device.

[0080] In a further embodiment of the present invention, it further includes: an online monitoring and feedback module for closed state;

[0081] The closed-state online monitoring feedback module includes a local feedback loop and a cross-feedback loop between adjacent modules;

[0082] The local feedback loop is integrated inside the protected power module and is used to directly acquire the conduction status signal of the discharge gap and the mechanical closing signal of the bypass switch;

[0083] The signal acquisition unit of the adjacent module cross feedback loop is integrated inside the adjacent power module cascaded with the protected power module. The adjacent module cross feedback loop is used to indirectly acquire the conduction status signal of the discharge gap and the mechanical closing signal of the bypass switch through the signal acquisition unit.

[0084] The local feedback loop and the adjacent module cross-feedback loop are based on a competition hazard verification mechanism, which feeds back the conduction status signal of the discharge gap and the mechanical closing signal of the bypass switch to the control system.

[0085] It should be noted that the local feedback loop is integrated inside the protected power module and directly connects to the signal output terminals of the discharge gap and the bypass switch. It collects the conduction status signal of the discharge gap (such as the current conduction signal) and the mechanical closing signal of the bypass switch (such as the limit switch signal and the contact closing signal) in real time. The signal acquisition unit of the adjacent module cross feedback loop is deployed inside the adjacent power module cascaded with the protected module. It indirectly collects the above two types of status signals through the cross-module signal sensing link (such as the coupling sensor and the isolated signal transmission channel). The signals collected by the two feedback loops are synchronously transmitted to the competition hazard verification mechanism. This mechanism uses logic such as signal timing comparison, amplitude consistency verification, and interference signal filtering to eliminate false signals caused by electromagnetic interference, contact jitter, etc. After filtering out the real and valid status information, it feeds it back to the control system to ensure the accuracy and timeliness of the feedback signal.

[0086] The local feedback loop in this embodiment enables direct and rapid acquisition of status signals, meeting the real-time requirements of the control system. The cross-feedback loops of adjacent modules form redundant acquisition channels, avoiding status acquisition failures caused by faults in the protected power modules themselves (such as internal circuit damage or signal link interruption), thus improving monitoring redundancy. The contention hazard verification mechanism solves the signal conflict and false triggering problems that may exist in dual-loop acquisition, ensuring that the status signals fed back to the control system are true and reliable. This allows the control system to accurately determine whether the discharge gap is effectively conducting and whether the bypass switch is reliably closed, and then adjust the control strategy in a timely manner (such as triggering loop retry and fault alarm), preventing bypass failure or secondary system faults caused by misjudgment of status, and ensuring the safe and stable operation of the power electronic system.

[0087] In one embodiment of the present invention, the power module is a cascaded converter internal power module.

[0088] In this embodiment, a fast bypass device is applied to the power modules inside a cascaded converter. Cascaded converters, with multiple power modules connected sequentially, enable high-voltage, high-power energy conversion and control, and are widely used in many key power fields such as high-voltage direct current transmission and flexible AC transmission. However, due to the large number of power modules and complex operating conditions, a single module failure can affect the entire converter and even the system operation. This embodiment applies a fast bypass device to the power modules inside such converters. The aim is to ensure that when a power module fails, the fast bypass device responds quickly, isolates the faulty module, and ensures that other normal modules continue to operate, maintaining the overall function of the converter and guaranteeing stable power supply to the power system. This effectively improves the reliability and stability of cascaded converters under complex operating conditions and is of great significance for ensuring the efficiency of power transmission and distribution.

[0089] In a further embodiment of the present invention, the converter adopts an MMC half-bridge topology, an MMC full-bridge topology, an M3C full-bridge topology, or a conventional cascaded full-bridge topology.

[0090] In a further embodiment of the present invention, the converter is connected to a power frequency grid, a low frequency grid, or a motor.

[0091] It should be noted that the industrial frequency grid is a common power supply network, typically operating at 50Hz or 60Hz. Connecting to the industrial frequency grid requires the converter to have stable and efficient power conversion capabilities to ensure reliable power transmission and distribution. Low-frequency grids exist in some special application scenarios, such as specific industrial equipment or certain power transmission needs. Their lower frequency places unique requirements on the frequency conversion and control performance of the converter. As motors are important loads in the power system, the converter connects to the motor to precisely adjust its operating parameters, achieving efficient drive and control.

[0092] Embodiments of the present invention also provide a power module, comprising:

[0093] A power unit, and a fast bypass device for a power module as described in the foregoing embodiments;

[0094] The fast bypass device is connected in parallel with the capacitor in the power unit, or in parallel with the two output terminals of the power unit.

[0095] Please see Figure 3 , Figure 3 The diagram illustrates the wiring configuration of the fast bypass device connected in parallel across the capacitor C of the power unit. When a power module malfunctions, the trigger signal F first triggers the discharge gap G, causing G to discharge under voltage. After triggering the discharge gap G, the trigger device F sends a closing signal to the bypass switch K after a delay of 10μs to 20μs, causing the bypass switch K to close rapidly. Upon closing, the voltage across the discharge gap drops to zero, extinguishing the arc in gap G. All current then flows through K, preventing the arc in gap G from burning for an extended period.

[0096] Please see Figure 4 , Figure 4 The diagram illustrates the wiring configuration of a fast bypass device connected in parallel to the two output terminals of the power unit. When a power module malfunctions, the trigger signal F first triggers the discharge gap G, causing G to discharge under voltage. After triggering the discharge gap G, the trigger device F sends a closing signal to the bypass switch K after a delay of 10μs to 20μs, causing the bypass switch K to close rapidly. After closing, the voltage across the discharge gap drops to zero, extinguishing the arc in gap G. All current then flows through K, preventing the arc in gap G from burning for an extended period.

[0097] The power module structure design of this invention not only enables rapid bypass in case of power module failure to ensure safe operation of the equipment, but also takes into account cost and ease of operation, effectively overcoming the shortcomings of existing bypass devices.

[0098] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0099] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0100] In the embodiments disclosed in this application, it should be understood that the disclosed devices / terminal equipment and methods can be implemented in other ways. For example, the device / terminal equipment embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling or direct coupling or communication connection may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0101] 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 fast bypass device for a power module, characterized in that, include: Triggerable discharge gap, bypass switch, dual-redundant triggering system and control system; The discharge gap is connected in parallel with the bypass switch, and the on-state physical impedance of the discharge gap is higher than the on-state physical impedance of the bypass switch. The dual-redundant triggering system includes two physically isolated triggering circuits; The control system is used to inject a trigger signal into the discharge gap through the two trigger circuits of the dual-redundant trigger system, and is also used to issue a bypass command to the bypass switch; the injection time of the trigger signal is earlier than the issuance time of the bypass command, and the time difference is within 10μs~20μs. The discharge gap is used to form a path when the trigger signal is received; The bypass switch is used to close when the bypass command is received.

2. The fast bypass device for a power module according to claim 1, characterized in that, The discharge gap is sealed within a closed cavity, and the bypass switch is independently located outside the closed cavity or placed together with the discharge gap within the closed cavity; The interior of the sealed cavity is either a vacuum environment or filled with an insulating gas, which is sulfur hexafluoride, nitrogen, or a mixture of nitrogen and carbon dioxide.

3. The fast bypass device for a power module according to claim 1, characterized in that, The dual-path redundant triggering system includes: a local triggering circuit and a cross-triggering circuit between adjacent modules; The local triggering circuit and the adjacent module cross-triggering circuit both adopt an independent power supply mode; The local triggering circuit is integrated inside the protected power module and is used to directly receive the local triggering signal sent by the control system and forward it to the discharge gap. The trigger control unit of the adjacent module cross triggering circuit is integrated inside the adjacent power module cascaded with the protected power module. A signal path is provided between the trigger control unit and the discharge gap of the protected power module. The adjacent module cross triggering circuit is used to receive the cross triggering signal issued by the control system through the trigger control unit and forward it to the discharge gap.

4. The fast bypass device for a power module according to claim 1, characterized in that, The discharge gap includes one or more pairs of high-voltage electrodes and ground electrodes arranged opposite each other. The high-voltage electrodes are connected to the high-voltage end of the protected power module, and the ground electrodes are connected to the low-voltage end of the protected power module.

5. The fast bypass device for a power module according to claim 4, characterized in that, At least two independent trigger cavities are embedded inside the ground electrode; Each of the independent trigger chambers is equipped with an independent trigger electrode, and the independent trigger electrode is electrically connected to each trigger circuit of the dual-redundant trigger system.

6. The fast bypass device for a power module according to claim 5, characterized in that, It also includes: an online monitoring and feedback module for the closed state; The closed-state online monitoring feedback module includes a local feedback loop and an adjacent module cross-feedback loop; The local feedback loop is integrated inside the protected power module and is used to directly acquire the conduction status signal of the discharge gap and the mechanical closing signal of the bypass switch. The signal acquisition unit of the adjacent module cross-feedback loop is integrated inside the adjacent power module cascaded with the protected power module. The adjacent module cross-feedback loop is used to indirectly acquire the conduction status signal of the discharge gap and the mechanical closing signal of the bypass switch through the signal acquisition unit. The local feedback loop and the adjacent module cross-feedback loop, based on a competition hazard verification mechanism, feed back the conduction status signal of the discharge gap and the mechanical closing signal of the bypass switch to the control system.

7. The fast bypass device for a power module according to any one of claims 1-6, characterized in that, The power module is an internal power module of a cascaded converter.

8. The fast bypass device for a power module according to claim 7, characterized in that, The converter adopts an MMC half-bridge topology, an MMC full-bridge topology, an M3C full-bridge topology, or a conventional cascaded full-bridge topology.

9. The fast bypass device for a power module according to claim 8, characterized in that, The converter is connected to the power frequency grid, the low frequency grid, or the motor.

10. A power module, characterized in that, include: A power unit, and a fast bypass device for a power module as described in any one of claims 1-9; The fast bypass device is connected in parallel with the capacitor in the power unit, or in parallel with the two output terminals of the power unit.

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