Multi-level fault protection method and monitoring system for hybrid multi-level converter, electronic equipment and medium

Abstract

The invention belongs to the field of power electronics, and discloses a multi-level fault protection method and monitoring system for a hybrid multi-level converter, electronic equipment and a medium. For the possible overvoltage, overcurrent and overheating faults of the hybrid multi-level converter, voltage / current / temperature signals are collected in real time and compared with a protection limit designed by hardware, a software alarm limit and a protection limit to trigger hardware / software protection, and the software / hardware protection is combined to guarantee safe operation of the converter. In order to monitor the operation state of the converter, an integrated data acquisition and processing architecture based on a voltage / current / temperature sensor is designed to collect core data and transmit the core data to a main controller for processing. The multi-level fault protection method for the hybrid multi-level converter has the advantages of being high in reliability, high in protection response speed and high in anti-jamming capability, and can be widely applied to the field of medium-high voltage power conversion, especially to various kinds of medium-high voltage converter equipment.

Description

Technical Field

[0001] The present invention belongs to the technical field of power electronics, and in particular relates to a hybrid multi-level converter multi-level fault protection method, a monitoring system, an electronic device and a medium. Background Art

[0002] Compared with other medium and high voltage multilevel topologies, such as modular multilevel converter (MMC) and neutral point clamped multilevel converter (NPC), hybrid multilevel converter (HCC) uses fewer switching devices, has better control performance and higher efficiency. Combined with silicon carbide (SiC) devices with better performance, it is expected to build a medium and high voltage converter with high power density and high efficiency.

[0003] For medium and high voltage multilevel converters that run for a long time, the real-time monitoring of faults and rapid protection under strong electromagnetic thermal coupling impact are the primary conditions for ensuring the reliable operation of SiC-based equipment. When various faults occur in SiC-based multilevel converters, due to the characteristics of SiC devices, the fault propagation speed is faster than that of Si devices. However, previous protection methods are mostly targeted at single faults, and there are problems such as difficulty in algorithm implementation and increased hardware costs. Therefore, it is necessary to optimize the protection strategy of multilevel converters to ensure the safe operation of medium and high voltage converters. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a hybrid multi-level converter multi-level fault protection method, monitoring system, electronic equipment and medium. The present invention aims to solve the problem of safe operation of the hybrid multi-level converter under strong electromagnetic thermal coupling impact.

[0005] The present invention provides a hybrid multi-level converter multi-level fault protection method, comprising:

[0006] Construct a fault monitoring system to monitor the operating status of the hybrid multilevel converter, namely capacitor voltage, output current, and half-bridge module temperature;

[0007] Design a hardware protection circuit integrated on the half-bridge module driver to protect the device in the event of a fault and send the generated hardware fault signal to the main controller;

[0008] Set the software protection algorithm. The software sets the alarm limit and alarm breaking time as well as the protection limit and protection breaking time. The various parameters monitored by the fault monitoring system are obtained in real time. When it is greater than the alarm / protection limit, the timing link is entered. If the duration is ≤ the breaking time, it is regarded as a disturbance of the sensor during the transmission process and no protection is given; if the duration is greater than the breaking time, the alarm / protection state is entered;

[0009] The software protection algorithm is combined with the hardware protection circuit. When the main controller receives a hardware fault signal, all switch signals are output to a low level and the emergency stop switch is controlled to shut down the power supply.

[0010] The hybrid multi-level converter comprises 12 half-bridge modules, 3 DC support capacitors and 3 flying capacitors, each capacitor having a discharge resistor;

[0011] The hardware protection circuit is integrated on the half-bridge module driving device, and the hardware protection circuit includes a desaturation short-circuit protection circuit, an overvoltage protection circuit and an overtemperature protection circuit. The hardware protection circuit is used to protect the device when a fault occurs and send the generated hardware fault signal to the main controller;

[0012] The software protection algorithm comprises:

[0013] Set the alarm limit and alarm limit breaking time, obtain the capacitor voltage, output current and half-bridge module temperature monitored by the fault monitoring system in real time, and enter the timing link when the capacitor voltage, output current and half-bridge module temperature are greater than the alarm limit, that is, record the duration of the capacitor voltage, output current and half-bridge module temperature greater than the alarm limit. If the duration is ≤ the alarm limit breaking time, it is regarded as a disturbance of the sensor during the transmission process and no protection is given; if the duration is greater than the alarm limit breaking time, the alarm state is entered;

[0014] Set the protection limit and the protection breaking limit time. After entering the alarm state, the capacitor voltage, output current and half-bridge module temperature of the hybrid multi-level converter are also obtained in real time through the fault monitoring system. When the capacitor voltage, output current and half-bridge module temperature are greater than the protection limit, the timing link is entered, that is, the duration of the capacitor voltage, output current and half-bridge module temperature greater than the protection limit is recorded. If the duration is greater than the protection breaking limit time, the software protection state is entered. At this time, all switch signals are output to a low level and the emergency stop switch is controlled to shut down the power supply;

[0015] The hybrid multi-level converter multi-level fault protection method is characterized in that: in the hardware protection circuit, its protection value can be changed by replacing the resistor on the circuit board;

[0016] The hybrid multi-level converter multi-level fault protection method, the alarm limit and protection limit of the capacitor voltage, output current, and half-bridge module temperature in the software protection algorithm can be modified in real time, and the alarm limit breaking time and protection limit breaking time are both T s , T s The value can also be modified by the program within 1μs to 1000μs;

[0017] A hybrid multi-level converter fault monitoring system, the fault monitoring system is used to monitor the operating state of the hybrid multi-level converter, namely, capacitor voltage, output current and half-bridge module temperature;

[0018] The fault monitoring system comprises a main controller, a voltage sensor, a current sensor and a temperature sensor, each of which can monitor the operating status of the hybrid multi-level converter, i.e., the capacitor voltage, the output current and the temperature of the half-bridge module, by direct measurement or indirect calculation; each sensor is equipped with a microcontroller and a signal processing circuit, and the monitoring quantity is converted into a small voltage signal by the signal processing circuit, and the small voltage signal is collected and converted into a logic level by the microcontroller, and the optical fiber is used to transmit data with the main controller;

[0019] In the hybrid multi-level converter fault monitoring system, the main controller includes a digital signal processor DSP and a programmable logic array FPGA;

[0020] An electronic device, comprising:

[0021] Memory for storing computer programs;

[0022] A processor, configured to implement the steps of the hybrid multi-level converter multi-level fault protection method when executing the computer program;

[0023] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of a hybrid multi-level converter multi-level fault protection method as claimed in claim 1 are implemented.

[0024] Beneficial effects:

[0025] 1. A hybrid multi-level converter multi-level fault protection method provided by the present invention adopts a controller combining DSP and FPGA, which has the advantages of fast operation speed and flexible input and output port configuration; data transmission uniformly adopts optical fiber transmission, which has the advantages of high reliability and strong anti-interference.

[0026] 2. The hybrid multi-level converter multi-level fault protection method provided by the present invention can change both the hardware protection value and the software protection value quickly, and has the advantages of flexibility and easy adjustment.

[0027] 3. The hybrid multi-level converter multi-level fault protection method provided by the present invention combines hardware protection circuits with software protection algorithms to monitor and protect the converter from possible overvoltage, overcurrent, and overtemperature faults, and has the characteristics of high reliability, fast protection response speed, and strong anti-interference.

[0028] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a topology diagram of a hybrid multilevel converter;

[0030] Figure 2 It is the structural diagram of the hybrid multi-level converter fault monitoring system;

[0031] Figure 3 This is the logic block diagram for software fault protection;

[0032] Figure 4 It is a multi-level protection flow chart combining software and hardware;

[0033] Figure 5 This is the A-phase driving waveform under extreme working conditions. DETAILED DESCRIPTION

[0034] In order to make the technical solutions, advantages and purposes of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of this application.

[0035] like Figure 1-5 As shown, a hybrid multi-level converter multi-level fault protection method, such as Figure 1 As shown, it is a hybrid multi-level converter topology diagram, including:

[0036] A fault monitoring system is built to monitor the operating status of the hybrid multilevel converter, namely the capacitor voltage, output current and half-bridge module temperature. Figure 2 It is the structural diagram of the hybrid multi-level converter fault monitoring system;

[0037] Design a hardware protection circuit integrated on the half-bridge module driver to protect the device in the event of a fault and send the generated hardware fault signal to the main controller;

[0038] Setting the software protection algorithm, the software fault protection logic of the present invention is as follows Figure 3As shown, the software sets the alarm limit and alarm breaking time as well as the protection limit and protection breaking time, and obtains various parameters monitored by the fault monitoring system in real time. When it is greater than the alarm / protection limit, it enters the timing link. If the duration is ≤ the breaking time, it is regarded as a disturbance of the sensor during the transmission process and no protection is given; if the duration is greater than the breaking time, it enters the alarm / protection state;

[0039] The software protection algorithm is combined with the hardware protection circuit. When the main controller receives the hardware fault signal, all switch signals are output to low level and the emergency stop switch is controlled to cut off the power supply. The multi-level protection process of software / hardware combination is as follows: Figure 4 As shown in the figure, when the converter faces extreme working conditions, such as output short circuit or device direct conduction, severe module overheating, capacitor rapid overvoltage and other faults, the hardware protection circuit can only protect the safety of a single half-bridge module, and cannot take into account the safety of the entire converter; therefore, after receiving the hardware fault signal, the software level will promptly shut down the drive signals of other devices and cut off the power supply to prevent the fault from spreading. Figure 5 As shown in the figure, it is the phase A driving waveform of the system when the system encounters extreme working conditions. Under this working condition, the system DC bus voltage is 1kV, and the hardware protection value of the desaturation short-circuit protection circuit is changed to 60A by changing the resistor on the circuit board. By increasing the modulation ratio, the output current of the converter is increased, thereby triggering the hardware protection to send a hardware fault signal. Figure 5 The response relationship between the device driving signal and the hardware fault signal under extreme working conditions is demonstrated. From the experimental results, it can be seen that when the hardware fault signal appears, the software receives the signal and quickly shuts off the driving signals of other devices. Therefore, the multi-level protection function proposed in the present invention can effectively protect the safety of the converter under extreme working conditions and ensure the stable and reliable operation of the converter.

[0040] Each capacitor of the hybrid multilevel converter is equipped with a discharge resistor. When a short circuit fault occurs between output phases, the system will enter the overcurrent protection state as preset. The hardware overcurrent protection is triggered first, and then the drive signal of each device is turned off, and the power supply side is disconnected from the output end. After that, each capacitor will discharge through the discharge resistor connected in parallel with it to protect the entire system and facilitate personnel to approach and clear the fault.

[0041] The hybrid multilevel converter includes 12 half-bridge modules, 3 DC support capacitors and 3 flying capacitors, each of which has a discharge resistor;

[0042] The hardware protection circuit is integrated on the half-bridge module driving device, and the hardware protection circuit includes a desaturation short-circuit protection circuit, an overvoltage protection circuit and an overtemperature protection circuit. The hardware protection circuit is used to protect the device when a fault occurs and send the generated hardware fault signal to the main controller;

[0043] The software protection algorithm comprises:

[0044] Set the alarm limit and alarm limit breaking time, obtain the capacitor voltage, output current and half-bridge module temperature monitored by the fault monitoring system in real time, and enter the timing link when the capacitor voltage, output current and half-bridge module temperature are greater than the alarm limit, that is, record the duration of the capacitor voltage, output current and half-bridge module temperature greater than the alarm limit. If the duration is ≤ the alarm limit breaking time, it is regarded as a disturbance of the sensor during the transmission process and no protection is given; if the duration is greater than the alarm limit breaking time, the alarm state is entered;

[0045] Set the protection limit and the protection breaking limit time. After entering the alarm state, the capacitor voltage, output current and half-bridge module temperature of the hybrid multi-level converter are also obtained in real time through the fault monitoring system. When the capacitor voltage, output current and half-bridge module temperature are greater than the protection limit, the timing link is entered, that is, the duration of the capacitor voltage, output current and half-bridge module temperature greater than the protection limit is recorded. If the duration is greater than the protection breaking limit time, the software protection state is entered. At this time, all switch signals are output to a low level and the emergency stop switch is controlled to shut down the power supply;

[0046] In the hybrid multi-level converter multi-level fault protection method, the protection value of the hardware protection circuit can be changed by replacing the resistor on the circuit board;

[0047] The hybrid multi-level converter multi-level fault protection method, the alarm limit and protection limit of the capacitor voltage, output current, and half-bridge module temperature in the software protection algorithm can be modified in real time, and the alarm limit breaking time and protection limit breaking time are both T s , T s The value can also be modified by the program within 1μs to 1000μs;

[0048] A hybrid multi-level converter fault monitoring system, the fault monitoring system is used to monitor the operating state of the hybrid multi-level converter, namely, capacitor voltage, output current and half-bridge module temperature;

[0049] The fault monitoring system comprises a main controller, a voltage sensor, a current sensor and a temperature sensor, each of which can monitor the operating status of the hybrid multi-level converter, i.e., the capacitor voltage, the output current and the temperature of the half-bridge module, by direct measurement or indirect calculation; each sensor is equipped with a microcontroller and a signal processing circuit, and the monitoring quantity is converted into a small voltage signal by the signal processing circuit, and the small voltage signal is collected and converted into a logic level by the microcontroller, and the optical fiber is used to transmit data with the main controller;

[0050] In the hybrid multi-level converter fault monitoring system, the main controller includes a digital signal processor DSP and a programmable logic array FPGA;

[0051] An electronic device, comprising:

[0052] Memory for storing computer programs;

[0053] A processor, configured to implement the steps of the hybrid multi-level converter multi-level fault protection method when executing the computer program;

[0054] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of a hybrid multi-level converter multi-level fault protection method are implemented.

[0055] In summary, the hybrid multi-level converter multi-level fault protection method proposed in the present invention combines the hardware protection circuit with the software protection algorithm to monitor and protect the overvoltage, overcurrent and overtemperature faults that may occur in the converter. It has the advantages of high reliability, fast protection response speed and strong anti-interference, and has the value of promotion and application in the field of power electronics.

[0056] It is hereby declared that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention is described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions, which should be included in the scope of the claims of the present invention.

Claims

1. A hybrid multi-level converter multi-level fault protection method, characterized in that: include: Construct a fault monitoring system to monitor the operating status of the hybrid multilevel converter, namely capacitor voltage, output current, and half-bridge module temperature; Design a hardware protection circuit integrated on the half-bridge module driver to protect the device in the event of a fault and send the generated hardware fault signal to the main controller; Set the software protection algorithm. The software sets the alarm limit and alarm breaking time as well as the protection limit and protection breaking time. The various parameters monitored by the fault monitoring system are obtained in real time. When it is greater than the alarm / protection limit, the timing link is entered. If the duration is ≤ the breaking time, it is regarded as a disturbance of the sensor during the transmission process and no protection is given; if the duration is greater than the breaking time, the alarm or protection state is entered; The software protection algorithm is combined with the hardware protection circuit. When the main controller receives a hardware fault signal, all switch signals are output to a low level and the emergency stop switch is controlled to cut off the power supply.

2. A hybrid multi-level converter multi-level fault protection method according to claim 1, characterized in that: The hybrid multi-level converter includes 12 half-bridge modules, 3 DC support capacitors and 3 flying capacitors, and each capacitor has a discharge resistor.

3. The hybrid multi-level converter multi-level fault protection method according to claim 1, characterized in that: The hardware protection circuit is integrated on the half-bridge module driving device, and the hardware protection circuit includes a desaturation short-circuit protection circuit, an overvoltage protection circuit and an overtemperature protection circuit. The hardware protection circuit is used to protect the device when a fault occurs and send the generated hardware fault signal to the main controller.

4. The hybrid multi-level converter multi-level fault protection method according to claim 1, characterized in that: The software protection algorithm comprises: Set the alarm limit and alarm limit breaking time, obtain the capacitor voltage, output current and half-bridge module temperature monitored by the fault monitoring system in real time, and enter the timing link when the capacitor voltage, output current and half-bridge module temperature are greater than the alarm limit, that is, record the duration of the capacitor voltage, output current and half-bridge module temperature greater than the alarm limit. If the duration is ≤ the alarm limit breaking time, it is regarded as a disturbance of the sensor during the transmission process and no protection is given; if the duration is greater than the alarm limit breaking time, the alarm state is entered; The protection limit and the protection breaking time are set. After entering the alarm state, the capacitor voltage, output current and half-bridge module temperature of the hybrid multi-level converter are also obtained in real time through the fault monitoring system. When the capacitor voltage, output current and half-bridge module temperature are greater than the protection limit, the timing link is entered, that is, the duration of the capacitor voltage, output current and half-bridge module temperature greater than the protection limit is recorded. If the duration is greater than the protection breaking time, the software protection state is entered. At this time, all switch signals are output as low level and the emergency stop switch is controlled to cut off the power supply.

5. The hybrid multi-level converter multi-level fault protection method according to claim 1, characterized in that: In the hardware protection circuit, the protection value can be changed by replacing the resistor on the circuit board.

6. The hybrid multi-level converter multi-level fault protection method according to claim 1, characterized in that: The alarm limits and protection limits of capacitor voltage, output current, and half-bridge module temperature in the software protection algorithm can be modified in real time, and the alarm limit breaking time and protection limit breaking time are both T s , T s The value can also be modified by program within 1μs to 1000μs.

7. A hybrid multilevel converter fault monitoring system, characterized in that: The fault monitoring system is used to monitor the operating status of the hybrid multi-level converter, namely the capacitor voltage, output current and half-bridge module temperature; The fault monitoring system includes a main controller, a voltage sensor, a current sensor and a temperature sensor. Each sensor can monitor the operating status of the hybrid multi-level converter, namely the capacitor voltage, the output current and the half-bridge module temperature, by direct measurement or indirect calculation; each sensor is equipped with a microcontroller and a signal processing circuit, and the monitoring quantity is converted into a small voltage signal by the signal processing circuit. The small voltage signal is collected by the microcontroller and converted into a logic level, and optical fiber is used to transmit data with the main controller.

8. A hybrid multilevel converter fault monitoring system according to claim 7, characterized in that: The main controller includes a digital signal processor DSP and a programmable logic array FPGA.

9. An electronic device, characterized in that: include: Memory for storing computer programs; A processor is used to implement the steps of a hybrid multi-level converter multi-level fault protection method as claimed in any one of claims 1 to 6 when executing the computer program.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the hybrid multi-level converter multi-level fault protection method as claimed in any one of claims 1 to 6 are implemented.

Images