Current zero-crossing self-turn-off method for direct-current transmission converter valve

Abstract

The invention provides a current zero-crossing self-turn-off method for a direct-current transmission converter valve, which is suitable for the technical field of power electronics and can enable a switch chip to work at a turn-off angle as small as possible, so that the probability of commutation failure caused by a slight fault is effectively reduced, and the reliability is improved. The method is suitable for the reverse blocking type switching device, and the reverse blocking type switching device comprises a switching chip and a driving circuit. The method comprises the following steps: a driving circuit detects that a switch chip has a zero-crossing signal; the driving circuit sends a zero-crossing turn-off signal to the switch chip, and the zero-crossing turn-off signal is used for controlling the switch chip to be turned off.

Description

Technical Field

[0001] The invention belongs to the technical field of power electronics, and in particular relates to a method for self-shutdown of a DC power transmission converter valve when current passes through zero. Background Art

[0002] At present, the line-commutated converter (LCC) usually adopts the following Figure 1 The thyristor (Silicon Controlled Rectifier, SCR) shown in the figure is used to achieve this. Figure 2 As shown, when a fault occurs in the power system, the voltage or current may cross zero in advance. Since the reverse recovery time of the thyristor is too long, the thyristor may not have time to complete reverse recovery, and thus reopen in the current direction before zero crossing, resulting in commutation failure.

[0003] To this end, a hybrid multilevel converter (Hybrid Commutated Converter, HCC) is introduced, such as Figure 3 As shown in the figure, the basic principle is to use a high-power reverse blocking (RB) integrated gate commutated thyristor (RB-IGCT) to replace the thyristor in the LCC converter. Since the reverse blocking IGCT contains a drive circuit, the reverse recovery time is very short, and the reverse recovery of the bridge arm current can be quickly completed when the voltage or current passes through zero, so as to solve the problem of commutation failure under minor faults.

[0004] However, since the HCC converter based on the reverse-resistance IGCT has more functions, the control logic based on the LCC converter valve is too simple and cannot match all the requirements of the HCC converter valve, resulting in poor consistency in controlling the zero-crossing of each reverse-resistance IGCT in the HCC converter. There is still a risk of commutation failure caused by the failure of some reverse-resistance IGCTs to shut down at zero crossing, and the reliability is still poor. Summary of the invention

[0005] The present invention proposes a method for self-shutdown of a DC power transmission converter valve when current passes through zero, which can enable a switch chip to operate at a shutdown angle as small as possible, so as to effectively reduce the probability of commutation failure caused by minor faults, thereby improving reliability.

[0006] In view of the above problems, the present invention adopts the following technical solutions:

[0007] In a first aspect, a method for self-shutdown of a DC power transmission converter valve when current passes through zero is provided. The method is applicable to a reverse resistance type switch device, which includes a switch chip and a drive circuit. The method includes:

[0008] The driving circuit detects that the switch chip has a zero-crossing signal;

[0009] The driving circuit sends a zero-crossing shutdown signal to the switch chip, and the zero-crossing shutdown signal is used to control the switch chip to shut down.

[0010] Among them, the reverse resistance type switching device is used to construct a rectifier circuit, and the rectifier circuit includes a plurality of reverse resistance type switching devices.

[0011] Optionally, the zero-crossing signal may include one or more of the following: a voltage of a switch chip, or a current of a switch chip.

[0012] Exemplarily, the switch chip may include a reverse-resistance integrated gate-commutated thyristor IGCT or other reverse-resistance fully-controlled switch devices.

[0013] In a second aspect, a reverse resistance type switching device is provided. The reverse resistance type switching device includes a switch chip and a drive circuit. The drive circuit is used to perform the following steps:

[0014] A zero-crossing signal is detected in the switch chip;

[0015] A zero-crossing shutdown signal is sent to the switch chip, and the zero-crossing shutdown signal is used to control the switch chip to shut down.

[0016] Among them, the reverse resistance type switching device is used to construct a rectifier circuit, and the rectifier circuit includes a plurality of reverse resistance type switching devices.

[0017] Optionally, the zero-crossing signal may include one or more of the following: a voltage of a switch chip, or a current of a switch chip.

[0018] Exemplarily, the switch chip may include a reverse-resistance integrated gate-commutated thyristor IGCT or other reverse-resistance fully-controlled switch devices.

[0019] Based on the zero-crossing self-shutdown method for the DC transmission converter valve provided by the present invention, the drive circuit and the switch chip of the reverse resistance switch device are integrated together. In this way, when the drive circuit receives a zero-crossing signal from the switch chip, it can send a zero-crossing shutdown signal to the switch chip, so that the switch chip can operate at the smallest possible shutdown angle, thereby effectively reducing the probability of commutation failure caused by minor faults and improving reliability.

[0020] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a structural schematic diagram of a rectifier circuit based on LCC;

[0023] Figure 2 A schematic diagram of a zero-crossing shutdown failure scenario in an LCC-based rectifier circuit;

[0024] Figure 3 It is a structural schematic diagram of a rectifier circuit based on HCC;

[0025] Figure 4 A schematic diagram of a scenario in which zero-crossing shutdown is successful in a rectifier circuit based on HCC;

[0026] Figure 5 A schematic diagram of the structure of a reverse resistance switch device provided in an embodiment of the present invention;

[0027] Figure 6 A schematic flow chart of a method for self-shutdown of a DC transmission converter valve when current passes through zero is provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] The embodiment of the present invention provides a reverse resistance type switching device. Figure 5 As shown, the reverse resistance switch device includes a switch chip and a drive circuit.

[0030] Among them, the switch chip may include a reverse-resistance IGCT or other reverse-resistance fully-controlled switch devices, and the drive circuit can be used to detect whether there is a zero-crossing signal in the switch chip, and when there is a zero-crossing signal in the switch chip, immediately send a zero-crossing shutdown signal to the switch chip, and the zero-crossing shutdown signal is used to control the switch chip to shut down.

[0031] Among them, the reverse resistance switching device is used to construct a rectifier circuit, such as a single-phase rectifier circuit (such as a single-phase bridge rectifier circuit), Figure 3The three-phase AC rectifier circuit shown, or a rectifier circuit with other structures, may include a plurality of reverse resistance switching devices.

[0032] by Figure 3 Taking the rectifier circuit shown in the figure as an example, the reverse resistance switch device may include a parallel structure consisting of a switch chip (IGCT) and a drive circuit, such as IGCT2+DRV2, IGCT5+DRV5, etc.

[0033] It should be noted that the number of reverse resistance switching devices included in different types of rectifier circuits may also be different. For example, the rectifier circuit may be Figure 3 The three-phase AC rectifier circuit shown in the figure includes six reverse resistance switching devices. It can also be a single-phase bridge rectifier circuit, in which case the rectifier circuit includes four reverse resistance switching devices.

[0034] Optionally, the zero-crossing signal may include one or more of the following: the voltage of the switch chip, or the current of the switch chip. Figure 4 For example, when the driving circuit detects that the voltage or current of the switch chip becomes zero, or changes direction, it can be regarded as a zero-crossing signal of the switch chip.

[0035] Exemplarily, the switch chip may include a reverse-resistance integrated gate-commutated thyristor IGCT or other reverse-resistance fully-controlled switch devices, which is not limited in the embodiments of the present invention.

[0036] like Figure 6 As shown, the embodiment of the present invention also provides a method for self-shutdown of a DC power transmission converter valve when the current passes through zero. The method can be applied to Figure 5 The reverse resistance switching device shown.

[0037] like Figure 6 As shown, the method comprises the following steps:

[0038] S601, the driving circuit detects that a zero-crossing signal exists in the switch chip.

[0039] Optionally, the zero-crossing signal may include one or more of the following: a voltage of a switch chip, or a current of a switch chip.

[0040] S602, the driving circuit sends a zero-crossing shutdown signal to the switch chip.

[0041] Among them, the zero-crossing shutdown signal is used to control the switch chip to shut down.

[0042] Based on the zero-crossing self-shutdown method for the DC transmission converter valve provided in the embodiment of the present invention, the drive circuit and the switch chip of the reverse resistance type switch device are integrated together. In this way, when the drive circuit receives a zero-crossing signal from the switch chip, it can send a zero-crossing shutdown signal to the switch chip, so that the switch chip can operate at the smallest possible shutdown angle, thereby effectively reducing the probability of commutation failure caused by minor faults and improving reliability.

[0043] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for automatically shutting down a DC power transmission converter valve when current passes through zero, characterized in that: Applicable to a reverse resistance type switching device, the reverse resistance type switching device comprises a switch chip and a drive circuit, the method comprises: The driving circuit detects that the switch chip has a zero-crossing signal; The driving circuit sends a zero-crossing shutdown signal to the switch chip, and the zero-crossing shutdown signal is used to control the switch chip to shut down.

2. The method for self-shutdown of a DC power transmission converter valve when current passes through zero according to claim 1, characterized in that: The reverse resistance type switching device is used to construct a rectifier circuit, and the rectifier circuit includes a plurality of the reverse resistance type switching devices.

3. The method for self-shutdown of a DC power transmission converter valve when current passes through zero according to claim 1, characterized in that: The zero-crossing signal includes one or more of the following: the voltage of the switch chip, or the current of the switch chip.

4. The method for self-shutdown of a DC power transmission converter valve when current passes through zero according to any one of claims 1 to 3, characterized in that: The switch chip includes a reverse resistance type integrated gate commutated thyristor IGCT.

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