A protection device for preventing breakdown of a power electronic device at a neutral point

Abstract

The utility model provides a kind of protection device for preventing electric power electronic device breakdown at neutral point, comprising: substrate;Detection module, for real-time acquisition voltage signal, current signal and the operating parameter of electric power electronic device of neutral point;Decision module is connected with the detection module, for receiving the signal and parameter collected, analysis and judgment and generate protection control instruction;Protection execution module is connected with the decision module, for executing corresponding protection action according to the protection control instruction;Energy absorption module is connected with the protection execution module, for absorbing surplus energy generated in system when protection action executes.The utility model can effectively avoid overvoltage, overcurrent and device abnormality to cause breakdown damage to electric power electronic device.

Description

Technical Field

[0001] This utility model relates to the field of breakdown protection technology, and in particular to a protection device for neutral point protection against breakdown of power electronic devices. Background Technology

[0002] With the rapid development of power electronics technology, power electronic devices, represented by IGBTs and MOSFETs, are widely used in neutral-point grounding systems, and their performance directly affects the stability and safety of the entire power system. As a critical node in the power system, the neutral point undertakes important functions such as current distribution, voltage balance, and fault isolation. Power electronic devices at this point often face complex operating challenges: on the one hand, transient overvoltages (such as switching overvoltages and lightning overvoltages) and short-circuit overcurrents may occur during system operation, causing the devices to withstand electrical stresses exceeding their rated values; on the other hand, long-term operation can lead to temperature increases, increased leakage current, and abnormal on-state voltage drops, gradually weakening their withstand voltage capabilities and ultimately causing breakdown faults. According to industry statistics, equipment downtime caused by power electronic device breakdowns accounts for more than 30% of all incidents in neutral-point systems, resulting not only in high maintenance costs but also potentially triggering chain reactions such as grid fluctuations.

[0003] To address these issues, various protection schemes have emerged in existing technologies. Early overcurrent protection relied heavily on fuses or circuit breakers, but their response times are typically in the tens of millisecond range, making it difficult to meet the nanosecond-level breakdown withstand requirements of power electronic devices. Overvoltage protection mainly uses passive components such as zinc oxide varistors, which can only suppress voltages of specific amplitudes and cannot adapt to a wide range of voltage fluctuations. While some integrated protection devices combine detection and execution functions, they suffer from insufficient detection accuracy, large errors in traditional voltage and current sensors under high-frequency signals, and a lack of real-time monitoring of device status parameters, making it difficult to predict faults in advance. Utility Model Content

[0004] To address the aforementioned problems, this utility model provides a neutral point protection device for preventing breakdown of power electronic devices.

[0005] To solve the above problems, the technical solution adopted by this utility model is as follows:

[0006] A neutral point protection device for preventing power electronic device breakdown includes: a base plate; a detection module for real-time acquisition of voltage and current signals at the neutral point, as well as operating parameters of the power electronic devices; a decision module connected to the detection module for receiving the acquired signals and parameters, analyzing and judging them, and generating protection control commands; a protection execution module connected to the decision module for executing corresponding protection actions according to the protection control commands; an energy absorption module connected to the protection execution module for absorbing excess energy generated in the system during protection action execution; and a communication module connected to both the detection module and the decision module for data transmission between modules and communication with an external control system; the detection module, decision module, protection execution module, energy absorption module, and communication module are all mounted on the base plate.

[0007] Preferably, the detection module includes: a voltage sensor for acquiring the voltage signal at the neutral point; a current sensor for acquiring the current signal at the neutral point; and a status monitoring unit for acquiring the temperature, leakage current, and on-state voltage drop parameters of the power electronic device.

[0008] Preferably, the decision module includes: a signal processing unit for filtering, amplifying, and performing analog-to-digital conversion on the acquired signal; and a central control unit connected to the signal processing unit, which has built-in protection criteria for determining whether to activate the protection mechanism and generating control commands based on the processed signal.

[0009] Preferably, the protection criteria include: overvoltage criteria: protection is activated when the detected voltage signal exceeds a set voltage threshold; overcurrent criteria: protection is activated when the detected current signal exceeds a set current threshold; and device abnormality criteria: protection is activated when the operating parameters of the power electronic device exceed the normal range.

[0010] Preferably, the protection execution module includes: a triggering unit that receives control commands from the decision module; and a fast switching unit controlled by the triggering unit, used to perform protection actions that electrically isolate the neutral point from the power electronic devices or connect them to a bypass circuit.

[0011] Preferably, the communication module is configured to: transmit data collected by the detection module to the decision module within the device; upload status information and alarm signals generated by the decision module to the external control system; and receive configuration instructions or remote control instructions from the external control system.

[0012] Preferably, the substrate is a multilayer printed circuit board, and the detection module, decision module, protection execution module, energy absorption module and communication module are integrated on the substrate through surface mount technology to form a compact integrated protection unit.

[0013] The beneficial effects of this utility model are as follows:

[0014] 1. The device shortens the signal transmission path through the compact integrated design of the multi-layer PCB substrate. The high-precision sensor of the detection module and the high-speed processing unit of the decision module can complete the entire process of "detection-judgment-execution-energy absorption" within ≤5ms, which can effectively avoid the breakdown damage of power electronic devices caused by overvoltage, overcurrent and device abnormalities.

[0015] 2. The integrated structure using SMT technology adapts to complex operating environments. The communication module supports bidirectional transmission of multiple protocols, which not only meets the needs of multiple scenarios such as new energy grid connection and rail transit, but also enables remote status monitoring, parameter configuration and control, thereby improving system security and operation and maintenance efficiency. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0017] Figure 2 This is a side view of the present invention.

[0018] Figure 3 This is a top view of the present invention;

[0019] In the diagram: 1. Substrate, 2. Detection module, 3. Decision module, 4. Protection execution module, 5. Energy absorption module, 6. Communication module. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0023] Reference Figure 1-3 A neutral point protection device for preventing power electronic device breakdown includes a substrate 1 and a detection module 2, a decision module 3, a protection execution module 4, an energy absorption module 5 and a communication module 6 integrated thereon. Each module has a clear function and is closely linked to form a complete protection closed loop.

[0024] Substrate 1, serving as the hardware carrier of the device, employs a multilayer printed circuit board (PCB) design, possessing high-density wiring capabilities and excellent electrical performance. The multilayer structure not only provides independent signal transmission channels for each module, reducing electromagnetic interference, but also lowers system noise through a well-designed grounding layer. Detection module 2, decision module 3, protection execution module 4, energy absorption module 5, and communication module 6 are all integrated onto the substrate using surface mount technology (SMT). This integrated design significantly reduces the device size, improves space utilization, and shortens the signal transmission paths between modules, ensuring timely protection response. Furthermore, the substrate surface is covered with a high-temperature resistant insulating coating, adapting to the complex operating environment of power systems.

[0025] Detection module 2 is responsible for capturing key system parameters in real time, providing data support for subsequent decision-making. It consists of three core components: a high-precision Hall voltage sensor that can accurately acquire AC or DC voltage signals at the neutral point over a wide frequency range with a measurement error ≤0.5%; a closed-loop Hall current sensor with fast response characteristics that can monitor current changes at the neutral point in real time with a response time <1μs; and a status monitoring unit that synchronously acquires operating parameters of power electronic devices through a distributed sensor network, including temperature (using infrared temperature measurement or thermocouple sensors, with a temperature range of -40℃ to 150℃), leakage current (resolution up to 1μA), and on-state voltage drop, comprehensively reflecting the health status of the devices.

[0026] Decision module 3 is used for data analysis and protection strategy generation. The signal processing unit first preprocesses the raw signal acquired by detection module 2: high-frequency noise is filtered out by a second-order Butterworth filter, the signal is amplified by an instrumentation amplifier (adjustable gain range 1-1000 times), and then the analog signal is converted into a digital signal by a 16-bit high-speed analog-to-digital converter (sampling rate ≥1MHz). The central control unit is built on a 32-bit high-performance microprocessor (clock frequency ≥100MHz) and has multiple built-in protection criteria: the overvoltage criterion sets multiple voltage thresholds (which can be adjusted by external configuration), and protection is triggered when the detected voltage exceeds the threshold; the overcurrent criterion also adopts a graded threshold design, combined with the current change rate for comprehensive judgment, to avoid false triggering by instantaneous inrush current; the device anomaly criterion establishes a parameter benchmark library, and when the temperature, leakage current, or on-state voltage drop exceeds the normal range by ±10%, it is determined that the device is abnormal. The central control unit performs real-time calculations on the processed signal, and the total delay from signal input to command generation is <10μs.

[0027] The protection execution module 4 ensures rapid response in the event of a fault. The trigger unit employs an optocoupler isolation design, generating a drive signal within 5μs after receiving control commands from the decision module 3. The fast switching unit, as the core execution component, uses a magnetically latched fast vacuum contactor or solid-state relay, possessing millisecond-level switching capability (opening time < 2ms, closing time < 3ms). It can electrically isolate the neutral point from power electronic devices according to instructions, or connect to a pre-designed bypass circuit to prevent continuous impact of fault energy on the devices. The switching unit also has a built-in current feedback circuit, which can monitor its own operating status in real time to ensure reliable operation.

[0028] Energy absorption module 5 plays a crucial role in protection operations, absorbing excess energy generated in the system and preventing secondary damage to devices from overvoltage and overcurrent. It mainly consists of a zinc oxide varistor (MOV), a metal oxide surge arrester (MOA), and a supercapacitor energy storage unit: the MOV rapidly conducts when the voltage exceeds its nominal value, releasing excess energy as heat; the MOA provides protection against transient impacts such as lightning overvoltages; and the supercapacitor unit can temporarily store some energy, releasing it through an energy feedback circuit after the system returns to normal, improving energy utilization. The module also includes internal temperature monitoring and fuse protection, automatically disconnecting when the energy absorption element overheats to prevent module damage.

[0029] Communication module 6 enables bidirectional data transmission. Internally, data collected by detection module 2 is transmitted in real-time to decision module 3 via SPI bus (transmission rate ≥10Mbps). Communication with the external control system supports multiple protocols, including Ethernet (TCP / IP), RS485 (Modbus-RTU), and wireless LoRa (transmission distance ≥1km). It can upload device operating status information (such as real-time voltage, current, and device temperature) and alarm signals (such as overvoltage alarms and device abnormality alarms) generated by decision module 3 to the monitoring center. Simultaneously, it receives configuration commands (such as adjusting voltage thresholds and modifying sampling frequencies) or remote control commands (such as manually triggering protection and resetting devices) from external sources, enabling remote operation and control. The communication module employs a redundant design to ensure the stability and continuity of data transmission.

[0030] Through the coordinated operation of the above modules, the protection device can quickly complete the protection process of "detection-judgment-execution-energy absorption" when power electronic devices face overvoltage, overcurrent or their own abnormalities, with a response time of ≤5ms. This greatly improves the safety and reliability of the neutral point system and is suitable for various scenarios such as new energy grid connection, rail transit, and industrial frequency conversion.

[0031] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A neutral point protection device for preventing breakdown of power electronic devices, characterized in that, include: Substrate (1); Detection module (2), used to collect the voltage signal and current signal of the neutral point and the operating parameters of the power electronic device in real time; The decision module (3) is connected to the detection module (2) and is used to receive the signals and parameters collected by the detection module (2), analyze and judge them and generate protection control commands. The protection execution module (4) is connected to the decision module (3) and is used to execute the corresponding protection actions according to the protection control commands. The energy absorption module (5) is connected to the protection execution module (4) and is used to absorb the excess energy generated in the system when the protection action is executed. The communication module (6) is connected to the detection module (2) and the decision module (3) respectively and is used to realize data transmission between the modules and communication with the external control system. The detection module (2), decision module (3), protection execution module (4), energy absorption module (5) and communication module (6) are all installed on the base plate (1).

2. The protection device according to claim 1, characterized in that, The detection module (2) includes: a voltage sensor for acquiring the voltage signal of the neutral point; a current sensor for acquiring the current signal of the neutral point; and a status monitoring unit for acquiring the temperature, leakage current and on-state voltage drop parameters of the power electronic device.

3. The protection device according to claim 2, characterized in that The decision module (3) includes: a signal processing unit for filtering, amplifying and analog-to-digital conversion of the acquired signal; and a central control unit connected to the signal processing unit, which has built-in protection criteria for determining whether to activate the protection mechanism and generating control commands based on the processed signal.

4. The protection device according to claim 3, characterized in that, The protection criteria include: overvoltage criterion: protection is activated when the detected voltage signal exceeds the set voltage threshold; overcurrent criterion: protection is activated when the detected current signal exceeds the set current threshold; device abnormality criterion: protection is activated when the operating parameters of the power electronic device exceed the normal range.

5. The protection device according to claim 1, characterized in that, The protection execution module (4) includes: a triggering unit, which receives control commands from the decision module (3); and a fast switching unit, which is controlled by the triggering unit and is used to perform protection actions to electrically isolate the neutral point from the power electronic devices or connect them to a bypass circuit.

6. The protection device according to claim 1, characterized in that, The communication module (6) is configured to: transmit the data collected by the detection module (2) to the decision module (3) within the device; upload the status information and alarm signals generated by the decision module (3) to the external control system; and receive configuration instructions or remote control instructions from the external control system.

7. The protection device according to claim 1, characterized in that, The substrate (1) is a multilayer printed circuit board. The detection module (2), decision module (3), protection execution module (4), energy absorption module (5) and communication module (6) are integrated on the substrate through surface mount technology to form a compact integrated protection unit.

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