Active turn-off method, system and equipment for hybrid commutation converter

Abstract

The embodiment of the invention relates to the technical field of converters, and discloses an active turn-off method, system and device for a hybrid commutation converter, and the method comprises the steps: obtaining the change rate of the current of a current bridge arm with time and commutation angle information in real time when commutation begins; when the change rate of the current of the current bridge arm along with time is abnormal, actively turning off a converter valve of the current bridge arm, and enabling the current to be subjected to phase commutation to the next bridge arm; and when the commutation angle reaches a set value, actively turning off the converter valve of the current bridge arm, so that the current is subjected to commutation to the next bridge arm. According to the embodiment of the invention, the commutation failure can be effectively resisted by detecting the current change rate; the natural commutation point effectively resists commutation failures under all working conditions and is a supplement of a current change rate criterion, the natural commutation point is turned off, so that the voltage and the current basically cross zero at the same time, and the reactive power demand is relatively low; the two turn-off methods are used in a mixed mode, and full-range commutation failure resistance can be achieved under small stress.

Description

Technical Field

[0001] The embodiments of the present disclosure relate to the technical field of converters, and in particular to an active shutdown method, system and device for a hybrid commutation converter. Background Art

[0002] In order to solve the problem of commutation failure in the prior art, a new converter topology based on reverse-resistance IGCT (Integrated Gate Commutated Thyristors) HCC (Hybrid Commutated Converter) is proposed. The basic principle of this topology is to replace the thyristors in the traditional LCC (Line Commutated Converter) converter valve with high-power reverse-resistance IGCT devices, and use the high withstand voltage and high current capacity of the reverse-resistance IGCT to complete the work of the original thyristor under normal operation, use the reverse-resistance IGCT's almost negligible reverse recovery period to achieve resistance to commutation failure under minor faults, and use the reverse-resistance IGCT's high current shutoff capability to achieve forced commutation under severe faults. Since the new HCC converter valve based on reverse-resistance IGCT has more functions, the original LCC control logic can no longer match the requirements of the HCC converter valve, so it is necessary to propose a new control logic for the HCC converter valve. Summary of the invention

[0003] The embodiments of the present disclosure provide a method, system and device for actively shutting down a hybrid commutation converter to solve or alleviate one or more of the above technical problems in the prior art.

[0004] According to one aspect of the present disclosure, there is provided an active shutdown method for a hybrid commutation converter, comprising:

[0005] When commutation starts, the current change rate of the current bridge arm over time and the commutation angle information are obtained in real time;

[0006] When the current change rate of the current arm over time is abnormal, actively shutting down the current commutation valve of the current arm to commutate the current to the next arm;

[0007] When the commutation angle reaches a set value, the commutation valve of the current bridge arm is actively turned off to commutate the current to the next bridge arm.

[0008] In a possible implementation, the abnormal change rate of the current of the bridge arm over time includes:

[0009] The current change rate of the current in the current bridge arm over time is a positive value.

[0010] In a possible implementation, when the commutation angle reaches a set value, actively shutting down the commutation valve of the current bridge arm to commutate the current to the next bridge arm includes:

[0011] When the commutation angle reaches the trigger angle, the commutation valve of the current bridge arm is actively turned off to commutate the current to the next bridge arm.

[0012] According to one aspect of the present disclosure, there is provided an active shutdown system for a hybrid commutation converter, comprising an acquisition unit and a valve-based electronic device, wherein the valve-based electronic device comprises a first commutation unit and a second commutation unit;

[0013] The acquisition unit is used to acquire the current change rate of the current bridge arm over time and the commutation angle information in real time when the commutation starts;

[0014] The first phase switching unit is used to actively shut down the current switching valve of the current bridge arm when the current change rate of the current bridge arm over time is abnormal, so as to switch the current to the next bridge arm;

[0015] The second commutation unit is used to actively turn off the commutation valve of the current bridge arm when the commutation angle reaches a set value, so that the current is commutated to the next bridge arm.

[0016] In a possible implementation, the abnormal change rate of the current of the bridge arm over time includes:

[0017] The current change rate of the current in the current bridge arm over time is a positive value.

[0018] In a possible implementation, the second phase switching unit includes:

[0019] The active shut-off module is used to actively shut down the commutation valve of the current bridge arm when the commutation angle reaches the trigger angle, so that the current is commutated to the next bridge arm.

[0020] According to one aspect of the present disclosure, there is provided an active shutdown device for a hybrid commutation converter, comprising:

[0021] Processor and memory;

[0022] The memory is used to store a computer program, and the processor calls the computer program stored in the memory to execute any one of the above-mentioned methods for actively shutting down the hybrid commutation converter.

[0023] According to one aspect of the present disclosure, a computer-readable storage medium is provided, in which a computer program is stored. When the computer program is executed by a processor, the processor is enabled to execute any one of the above-mentioned methods for actively shutting down a hybrid commutation converter.

[0024] The exemplary embodiments of the present disclosure have the following beneficial effects: the exemplary embodiments of the present disclosure can effectively resist commutation failure by detecting the current change rate. At the same time, since the shutdown operation occurs when the current change rate is about zero, the bridge arm can be shut down when the current is minimum, reducing the shutdown stress of the device. The natural commutation point effectively resists commutation failure under all working conditions, which is a supplement to the current change rate criterion. The natural commutation point shutdown makes the voltage and current basically pass zero at the same time, and the reactive power demand is small; the mixed use of the two shutdown methods can achieve full range of commutation failure resistance under less stress.

[0025] The details of one or more embodiments of the present application are presented in the following drawings and descriptions. Other features and advantages of the present application will become apparent from the accompanying drawings. It should be understood that the above general description and the detailed descriptions below are only exemplary and explanatory and cannot limit the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification are used to explain the principles of the present disclosure. Obviously, the accompanying drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0027] Figure 1 is a flow chart of an active shutdown method of a hybrid commutation converter according to the exemplary embodiment;

[0028] Figure 2 is a shutdown schematic diagram based on di / dt (current change rate over time) detection in an active shutdown method of a hybrid commutation converter of this exemplary embodiment;

[0029] Figure 3 is a schematic diagram of natural commutation point shutdown in an active shutdown method of a hybrid commutation converter of this exemplary embodiment;

[0030] Figure 4 is a block diagram of an active shutdown system of a hybrid commutated converter according to the exemplary embodiment;

[0031] Figure 5 is a schematic structural diagram of an active shutdown device of a hybrid commutation converter according to this exemplary embodiment. DETAILED DESCRIPTION

[0032] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as being limited to the examples set forth herein; on the contrary, these embodiments are provided so that the present disclosure will be more comprehensive and complete, and the concepts of the example embodiments are fully conveyed to those skilled in the art. The described features, structures, or characteristics may be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced while omitting one or more of the specific details, or other methods, components, devices, steps, etc. may be adopted. In other cases, known technical solutions are not shown or described in detail to avoid obscuring various aspects of the present disclosure.

[0033] In addition, the accompanying drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and thus their repeated description will be omitted. Some of the block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software form, or implemented in one or more hardware units or integrated circuits, or implemented in different networks and / or processor devices and / or microcontroller devices.

[0034] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the steps. For example, some steps may be decomposed, while some steps may be combined or partially combined, so the actual execution order may change according to the actual situation.

[0035] The terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example.

[0036] In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or sub-modules is not necessarily limited to those steps or sub-modules explicitly listed, but may include other steps or sub-modules not explicitly listed or inherent to these processes, methods, products, or apparatuses.

[0037] Figure 1 is a flow chart of an active shutdown method of a hybrid commutation converter according to the exemplary embodiment of the present invention. Figure 1As shown, an exemplary embodiment of the present disclosure provides an active shutdown method of a hybrid commutation converter, comprising:

[0038] When S1 commutation starts, the current change rate of the current bridge arm over time and the commutation angle information are obtained in real time;

[0039] When the current change rate of the current arm over time is abnormal, S2 actively turns off the commutation valve of the current arm to commutate the current to the next arm;

[0040] When the commutation angle reaches the set value, S3 actively turns off the commutation valve of the current bridge arm to commutate the current to the next bridge arm.

[0041] The HCC hybrid active shutdown strategy in this embodiment is a hybrid shutdown strategy of natural commutation point shutdown and current change rate detection shutdown. Among them, the natural commutation point refers to the time point when the voltage passes through zero under normal circumstances. In order to achieve the goal of natural commutation point shutdown, the system needs to have angle information during the commutation process and send down VBE (Valve Base Electronics). When the next bridge arm is triggered to open, that is, the commutation begins, VBE starts timing using the angle information obtained from the system, and actively shuts down when the timing reaches the trigger angle β. At this time, there is no need to consider whether there is still current on the bridge arm, because the presence of current means active shutdown, and sending a shutdown signal without current will not cause problems. Using the angle delay method, the converter valve can be shut down at the natural commutation point. For most commutation failures, the approximate fault waveform is Figure 2 and Figure 3 As shown, the fault current waveform will most likely show a process of first decreasing and then increasing during the commutation failure process. Therefore, there will be a process in which di / dt changes from negative to 0 and then to positive. For more serious faults, the current may not have a negative rate of change and will continue to rise directly. In response to this phenomenon, this embodiment installs a current sensor on the bridge arm, uploads the bridge arm current data into VBE through the current sensor, and calculates the current change rate through VBE. When the current change rate becomes positive within the commutation window period, issuing an active shutdown command can force the current to be commutated to the next bridge arm, thereby avoiding commutation failure.

[0042] Figure 2 Schematic diagram of a shutdown method based on di / dt (current change rate over time) in an active shutdown method of a hybrid commutation converter of this exemplary embodiment ( Figure 2 in, u L Indicates the line voltage, i T4 is the current of one of the multiple converter valves 4, u LNrepresents the line voltage rating, α0 represents the trigger angle rating, μ0 represents the commutation angle rating, characterizing the commutation time, γ0 represents the turn-off angle rating, used for device recovery, π represents the difference between the angle value when the normal voltage passes through zero and the angle value when the voltage drops to 0 due to an AC fault, t1 represents the time when the line voltage reaches the peak value, t2 represents the commutation start time, t3 represents the time when the voltage drops to 0 due to an AC fault, and ωt represents the angle); Figure 2 As shown, at the beginning of commutation (time t2), this embodiment obtains the current change rate over time (di / dt) of the current arm in real time, and performs timing, and then feeds back the current change rate over time, commutation angle information and timing information to VBE, and when the current change rate over time of the current arm is abnormal, the current switching valve of the current arm is actively turned off to commutate the current to the next arm; illustratively, a current sensor is installed on the bridge arm, and the bridge arm current is detected in real time by the current sensor and uploaded to VBE, and the current change rate over time is calculated by VBE. During the commutation window, when it is detected that the current change rate over time of the current arm changes from negative to 0 and then to positive, or when it is detected that the current change rate over time of the current arm is directly positive, an active shutdown instruction is issued by VBE to actively shut down the current switching valve of the bridge arm, so that the current is commutated to the next arm;

[0043] Figure 3 This is a schematic diagram of natural commutation point shutdown in an active shutdown method of a hybrid commutation converter of this exemplary embodiment ( Figure 3 in, u L Indicates the line voltage, i T4 is the current of one of the multiple converter valves 4, u LN represents the line voltage rating, α0 represents the trigger angle rating, μ0 represents the commutation angle rating, characterizing the commutation time, γ0 represents the turn-off angle rating, used for device recovery, π represents the difference between the angle value when the normal voltage passes through zero and the angle value when the voltage drops to 0 due to an AC fault, t1 represents the time when the line voltage reaches the peak value, t2 represents the commutation start time, t3 represents the time when the voltage drops to 0 due to an AC fault, t4 represents the normal voltage zero crossing time, ωt represents the angle, and β represents the trigger angle); Figure 3As shown, at the beginning of commutation (time t2), this embodiment acquires the commutation angle information in real time and performs timing. When the commutation angle reaches the set value, the converter valve of the current bridge arm is actively turned off to commutate the current to the next bridge arm. Exemplarily, the real-time commutation angle information and the corresponding time information are uploaded to VBE. When the commutation angle reaches the trigger angle β, the shutdown command is issued through VBE to actively shut down the converter valve of the current bridge arm to commutate the current to the next bridge arm. It is worth noting that when the timing reaches the trigger angle β, active shutdown is performed. At this time, there is no need to consider whether there is still current on the bridge arm, because active shutdown is performed if there is current, and sending a shutdown signal without current will not cause any problems. This embodiment uses the angle delay method to realize the shutdown of the converter valve at the natural commutation point.

[0044] In summary, this embodiment can effectively resist commutation failure by detecting the current change rate. At the same time, since the shutdown operation occurs when the current change rate is about 0, the bridge arm can be shut down when the current is minimum, reducing the shutdown stress of the device. The natural commutation point effectively resists commutation failure under all working conditions, which is a supplement to the current change rate criterion. The natural commutation point shutdown makes the voltage and current basically pass zero at the same time, and the reactive power demand is small. The mixed use of the two shutdown methods can achieve full range of commutation failure resistance under less stress.

[0045] Exemplarily, the abnormal change rate of the current of the current bridge arm over time includes:

[0046] The current change rate of the current in the current bridge arm over time is a positive value.

[0047] Exemplarily, when the commutation angle reaches a set value, actively shutting off the commutation valve of the current bridge arm to commutate the current to the next bridge arm includes:

[0048] When the commutation angle reaches the trigger angle, the commutation valve of the current bridge arm is actively closed to commutate the current to the next bridge arm.

[0049] Figure 4 is a block diagram of an active shutdown system of a hybrid commutation converter of the present exemplary embodiment. Figure 4 As shown, an exemplary embodiment of the present disclosure provides an active shutdown system for a hybrid commutation converter, comprising an acquisition unit 10 and a valve base electronic device 20, wherein the valve base electronic device 20 comprises a first commutation unit 30 and a second commutation unit 40;

[0050] The acquisition unit 10 is used to obtain the current change rate of the current bridge arm over time and the commutation angle information in real time when the commutation starts;

[0051] The first phase switching unit 30 is used to actively shut down the current switching valve of the current bridge arm when the current change rate of the current bridge arm over time is abnormal, so as to switch the current to the next bridge arm;

[0052] The second commutation unit 40 is used to actively turn off the commutation valve of the current bridge arm when the commutation angle reaches a set value, so as to commutate the current to the next bridge arm.

[0053] Exemplarily, the abnormal change rate of the current of the current bridge arm over time includes:

[0054] The current change rate of the current in the current bridge arm over time is a positive value.

[0055] Exemplarily, the second switching unit includes:

[0056] The active shutdown module is used to actively shut down the commutation valve of the current bridge arm when the commutation angle reaches the trigger angle, so that the current commutates to the next bridge arm.

[0057] Figure 5 is a schematic diagram of the structure of an active shutdown device of a hybrid commutation converter according to this exemplary embodiment. Figure 5 As shown, corresponding to the active shutdown method of the hybrid commutation converter provided above, the present invention also provides an active shutdown device for a hybrid commutation converter. Since the embodiment of the device is similar to the above method embodiment, the description is relatively simple. For relevant parts, please refer to the description of the above method embodiment. The device described below is only schematic. The device may include: a processor (processor) 1, a memory (memory) 2 and a communication bus (i.e., the above device bus) and a search engine, wherein the processor 1 and the memory 2 communicate with each other through the communication bus and communicate with the outside through the communication interface. The processor 1 can call the logic instructions in the memory 2 to execute the active shutdown method of the hybrid commutation converter.

[0058] In addition, the logic instructions in the above-mentioned memory 2 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art or the part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: a storage chip, a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a disk or an optical disk, and other media that can store program codes.

[0059] On the other hand, an embodiment of the present invention further provides a processor-readable storage medium, on which a computer program 3 is stored. When the computer program 3 is executed by the processor 1, the active shutdown method of the hybrid commutation converter provided in the above embodiments is implemented.

[0060] The processor-readable storage medium can be any available medium or data storage device that can be accessed by the processor 1, including but not limited to magnetic storage (such as floppy disks, hard disks, magnetic tapes, magneto-optical disks (MO), etc.), optical storage (such as CD, DVD, BD, HVD, etc.), and semiconductor storage (such as ROM, EPROM, EEPROM, non-volatile memory (NANDFLASH), solid-state drive (SSD)), etc.

[0061] The above are only preferred implementations of the present disclosure, and the protection scope of the present disclosure is not limited to the above embodiments. All technical solutions under the concept of the present disclosure belong to the protection scope of the present disclosure. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present disclosure should be regarded as the protection scope of the present disclosure.

Claims

1. An active shutdown method for a hybrid commutation converter, characterized in that: include: When commutation starts, the current change rate of the current bridge arm over time and the commutation angle information are obtained in real time; When the current change rate of the current arm over time is abnormal, actively shutting down the current commutation valve of the current arm to commutate the current to the next arm; When the commutation angle reaches a set value, the commutation valve of the current bridge arm is actively turned off to commutate the current to the next bridge arm.

2. The active shutdown method of the hybrid commutation converter according to claim 1, characterized in that: The abnormal change rate of the current of the bridge arm over time includes: The current change rate of the current in the current bridge arm over time is a positive value.

3. The active shutdown method of a hybrid commutation converter according to claim 1 or 2, characterized in that: When the commutation angle reaches a set value, actively shutting off the commutation valve of the current bridge arm to commutate the current to the next bridge arm includes: When the commutation angle reaches the trigger angle, the commutation valve of the current bridge arm is actively turned off to commutate the current to the next bridge arm.

4. An active shutdown system for a hybrid commutation converter, characterized in that: It includes an acquisition unit and a valve base electronic device, wherein the valve base electronic device includes a first phase switching unit and a second phase switching unit; The acquisition unit is used to acquire the current change rate of the current bridge arm over time and the commutation angle information in real time when the commutation starts; The first phase switching unit is used to actively shut down the current switching valve of the current bridge arm when the current change rate of the current bridge arm over time is abnormal, so as to switch the current to the next bridge arm; The second commutation unit is used to actively turn off the commutation valve of the current bridge arm when the commutation angle reaches a set value, so that the current is commutated to the next bridge arm.

5. The active shutdown system of the hybrid commutation converter according to claim 4, characterized in that: The abnormal change rate of the current of the bridge arm over time includes: The current change rate of the current in the current bridge arm over time is a positive value.

6. The active shutdown system of the hybrid commutation converter according to claim 4 or 5, characterized in that: The second phase switching unit comprises: The active shut-off module is used to actively shut down the commutation valve of the current bridge arm when the commutation angle reaches the trigger angle, so that the current is commutated to the next bridge arm.

7. An active shutdown device for a hybrid commutation converter, characterized in that: include: Processor and memory; The memory is used to store a computer program, and the processor calls the computer program stored in the memory to execute the active shutdown method of the hybrid commutation converter according to any one of claims 1 to 3.

8. 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 processor is enabled to execute the active shutdown method of the hybrid commutation converter according to any one of claims 1 to 3.

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