WO2022174623A1 - Series-type inverter system and protection method therefor - Google Patents

Series-type inverter system and protection method therefor Download PDF

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Publication number
WO2022174623A1
WO2022174623A1 PCT/CN2021/128032 CN2021128032W WO2022174623A1 WO 2022174623 A1 WO2022174623 A1 WO 2022174623A1 CN 2021128032 W CN2021128032 W CN 2021128032W WO 2022174623 A1 WO2022174623 A1 WO 2022174623A1
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Prior art keywords
series
inverter
controllable switch
switch circuit
bidirectionally controllable
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PCT/CN2021/128032
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French (fr)
Chinese (zh)
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陈鹏
孙帅
李顺
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阳光电源股份有限公司
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Publication of WO2022174623A1 publication Critical patent/WO2022174623A1/en

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/5387—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
    • H02M7/53871—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
    • H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
    • H02H7/122—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for inverters, i.e. dc/ac converters

Definitions

  • the invention relates to the technical field of power electronics, and more particularly, to a series inverter system and a protection method thereof.
  • a series inverter system includes a main circuit and a protection circuit
  • the protection circuit includes: a control unit and a bidirectionally controllable switch circuit; the bidirectionally controllable switch circuit is connected in series on the midpoint lead-out line after the DC side of the two inverter units are connected in series; the control unit is used for When detecting that the current on the bidirectionally controllable switch circuit exceeds a threshold value, control the bidirectionally controllable switch circuit to disconnect from the conduction path with the same direction as the current fault current, or control the bidirectionally controllable switch The paths that conduct the circuit in both directions are disconnected at the same time.
  • the split transformer or the two independent transformers are used independently by one of the series inverter systems, or the split transformer or the two independent transformers are shared by a plurality of the series inverter systems .
  • the protection circuit includes a bidirectionally controllable switch circuit; the bidirectionally controllable switch circuit is connected in series on the midpoint lead-out line after the DC sides of the two inverter units are connected in series;
  • FIG. 1 is a schematic structural diagram of a series inverter system disclosed in the prior art
  • 6a is a schematic structural diagram of a bidirectional controllable switch circuit disclosed in an embodiment of the present invention.
  • inverter unit 1 the inverter unit leading out the positive line in the above series inverter system
  • inverter unit 2 the inverter unit leading out the negative line
  • the current I1 on the positive line is unbalanced with the current I2 on the negative line, and there is a current flowing on the neutral line, and the magnitude of the current is equal to
  • the bidirectionally controllable switching circuit includes: two IGBTs connected in reverse series, and each IGBT is connected in reverse parallel with a diode.
  • Q3 and Q4 are used to represent the two IGBTs, respectively, and the emitter of Q3 is connected to the emitter of Q4; when Q3 is turned on and Q4 is turned off, the bidirectional controllable switching circuit is from right to left.
  • Q4 is turned on and Q3 is turned off, the bidirectional controllable switch circuit is turned on from right to left and turned off from left to right.
  • the bidirectionally controllable switching circuit includes: a MOSFET and an IGBT, the MOSFET and the IGBT are connected in series in reverse, and the IGBT is connected in parallel with a diode.
  • Q5 and Q6 are used to represent the MOSFET and IGBT, respectively, and the drain of Q5 is connected to the collector of Q6; when Q5 is turned on and Q6 is turned off, the bidirectional controllable switching circuit is from right to left. When Q6 is turned on and Q5 is turned off, the bidirectional controllable switch circuit is turned off from right to left and turned on from left to right.
  • each inverter unit has a unique inverter bridge; or, each inverter unit is composed of multiple inverter bridges, and the multiple inverter bridges The DC side is connected in parallel and the AC side is connected in parallel.
  • the split transformer or the two independent transformers are used independently by one of the series inverter systems, or the split transformer or the two independent transformers are used independently. A plurality of the series inverter systems are shared.
  • the embodiment of the present invention further discloses a protection method for a series inverter system, wherein the series inverter system includes a main circuit and a protection circuit;
  • the main circuit includes: two inverter units; the DC sides of the two inverter units are connected in series and then lead out a positive line and a negative line, which are respectively connected to the positive and negative electrodes of the input source; the two The midpoint of the series-connected DC side of the inverter units and the midpoint of the input source are both grounded through the grounding unit or both are directly grounded; the AC sides of the two inverter units are respectively connected to the two split windings on the low voltage side of the split transformer Or connect to the windings on the low-voltage side of two independent transformers respectively;
  • the protection circuit includes a bidirectionally controllable switch circuit; the bidirectionally controllable switch circuit is connected in series on the midpoint lead-out line after the DC sides of the two inverter units are connected in series;
  • Step S01 detecting the magnitude of the current on the bidirectionally controllable switch circuit
  • Step S02 judging whether the current on the bidirectionally controllable switch circuit exceeds a threshold value, if yes, go to Step S03, if not, go back to Step S01;
  • Step S03 control the bidirectionally controllable switch circuit to disconnect from the conduction path in the same direction of the current fault current, or control the bidirectionally controllable switch circuit to simultaneously disconnect the bidirectional conduction path.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)

Abstract

The present application discloses a series-type inverter system and a protection method therefor. In the present application, a fault current is suppressed when a positive line or negative line is short-circuited to the ground. A protective circuit comprises: a control unit and a bidirectionally controllable switching circuit; the bidirectionally controllable switching circuit is connected in series on a midpoint lead-out line obtained after direct-current sides of two inverter units are connected in series; the control unit is configured to, when it is detected that a current of the bidirectionally controllable switching circuit exceeds a threshold, control the bidirectionally controllable switching circuit to be disconnected from a conduction path that is in the same direction as a current fault current direction, or control bidirectional conduction paths of the bidirectionally controllable switching circuit to be simultaneously disconnected.

Description

一种串联型逆变系统及其保护方法A series inverter system and its protection method
本申请要求于2021年02月20日提交中国专利局、申请号为202110192524.5、申请名称为“一种串联型逆变系统及其保护方法”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。This application claims the priority of the Chinese patent application with the application number 202110192524.5 and the application title "A series inverter system and its protection method" filed with the China Patent Office on February 20, 2021, the entire contents of which are incorporated by reference in this application.
技术领域technical field
本发明涉及电力电子技术领域，更具体地说，涉及一种串联型逆变系统及其保护方法。The invention relates to the technical field of power electronics, and more particularly, to a series inverter system and a protection method thereof.
背景技术Background technique
图1示出了一种串联型逆变系统，包括：两个逆变单元；这两个逆变单元的直流侧相串联后引出一根正线和一根负线，分别接入输入源的正极和负极；这两个逆变单元的直流侧串联后的中点以及所述输入源的中点通过接地单元接地或直接接地，此时两中点对地电压相等、基本为零，相当于两中点之间有一根虚拟连接的中线(当然也可以将该虚拟连接的中线实体化)；这两个逆变单元的交流侧分别接入分裂变压器低压侧的两个分裂绕组(或分别接入两个独立变压器低压侧的绕组)。Figure 1 shows a series inverter system, including: two inverter units; the DC sides of the two inverter units are connected in series and lead out a positive line and a negative line, which are respectively connected to the input source Positive pole and negative pole; the midpoint of the DC side of the two inverter units connected in series and the midpoint of the input source are grounded or directly grounded through the grounding unit. At this time, the voltage between the two midpoints is equal and basically zero, which is equivalent to There is a virtually connected neutral line between the two neutral points (of course, the virtually connected neutral line can also be materialized); the AC sides of the two inverter units are respectively connected to the two split windings on the low voltage side of the split transformer (or respectively connected to the two split windings). into the windings on the low-voltage side of two separate transformers).
但是对于所述串联型逆变系统来说，一旦所述正、负线中的一根对地短路(图2以所述正线对地短路为例)，或者所述正、负线中的一根对地阻抗过低，或者两个逆变单元之间功率严重不均衡，则会使得其中一个逆变单元的直流侧产生大电流，造成回路中的功率半导体器件或其他器件过流损坏。But for the series inverter system, once one of the positive and negative lines is short-circuited to ground (Fig. 2 takes the positive line to ground short-circuit as an example), or one of the positive and negative lines is short-circuited to ground If the impedance of one line to ground is too low, or the power between the two inverter units is seriously unbalanced, a large current will be generated on the DC side of one of the inverter units, causing overcurrent damage to the power semiconductor devices or other devices in the loop.
申请内容Application content
有鉴于此，本发明提供一种串联型逆变系统及其保护方法，以抑制故障电流。In view of this, the present invention provides a series inverter system and a protection method thereof to suppress fault current.
一种串联型逆变系统，包括主电路和保护电路；A series inverter system includes a main circuit and a protection circuit;
所述主电路包括：两个逆变单元；所述两个逆变单元的直流侧相串联后引 出一根正线和一根负线，分别接入输入源的正极和负极；所述两个逆变单元直流侧串联后的中点以及所述输入源的中点通过接地单元接地或直接接地；所述两个逆变单元的交流侧分别接入分裂变压器低压侧的两个分裂绕组或者分别接入两个独立变压器低压侧的绕组；The main circuit includes: two inverter units; the DC sides of the two inverter units are connected in series and then lead out a positive line and a negative line, which are respectively connected to the positive and negative electrodes of the input source; the two The midpoint of the series-connected DC side of the inverter units and the midpoint of the input source are grounded or directly grounded through the grounding unit; the AC sides of the two inverter units are respectively connected to the two split windings on the low-voltage side of the split transformer or are Access the windings on the low-voltage side of two independent transformers;
所述保护电路包括：控制单元和双向可控的开关电路；所述双向可控的开关电路串联在所述两个逆变单元直流侧串联后的中点引出线上；所述控制单元用于在检测到所述双向可控的开关电路上的电流超过阈值时，控制所述双向可控的开关电路与当前故障电流方向同向的导通路径断开，或者控制所述双向可控的开关电路双向导通的路径同时断开。The protection circuit includes: a control unit and a bidirectionally controllable switch circuit; the bidirectionally controllable switch circuit is connected in series on the midpoint lead-out line after the DC side of the two inverter units are connected in series; the control unit is used for When detecting that the current on the bidirectionally controllable switch circuit exceeds a threshold value, control the bidirectionally controllable switch circuit to disconnect from the conduction path with the same direction as the current fault current, or control the bidirectionally controllable switch The paths that conduct the circuit in both directions are disconnected at the same time.
可选的，所述双向可控的开关电路包括至少一个功率半导体器件。Optionally, the bidirectionally controllable switch circuit includes at least one power semiconductor device.
可选的，所述双向可控的开关电路包括：两个反向串联的MOSFET。Optionally, the bidirectionally controllable switch circuit includes: two MOSFETs connected in series in opposite directions.
可选的，所述双向可控的开关电路包括：两个反向串联的IGBT，并且每个IGBT上各反向并联一个二极管。Optionally, the bidirectionally controllable switch circuit includes: two IGBTs connected in reverse series, and each IGBT is connected in reverse parallel with a diode.
可选的，所述双向可控的开关电路包括：一个MOSFET和一个IGBT，所述MOSFET和所述IGBT反向串联，并且所述IGBT上反向并联一个二极管。Optionally, the bidirectionally controllable switch circuit includes: a MOSFET and an IGBT, the MOSFET and the IGBT are connected in reverse series, and a diode is connected in reverse parallel to the IGBT.
可选的，所述双向可控的开关电路包括：两个反向串联的二极管，并且每个二极管上各并联一个电磁式开关电器。Optionally, the bidirectionally controllable switch circuit includes: two diodes connected in series in opposite directions, and each diode is connected in parallel with an electromagnetic switching device.
可选的，所述双向可控的开关电路为逆导型IGBT。Optionally, the bidirectionally controllable switch circuit is a reverse conduction IGBT.
可选的，每个逆变单元均具有唯一的逆变桥；或者，每个逆变单元均由多个逆变桥组成，所述多个逆变桥的直流侧并联、交流侧并联。Optionally, each inverter unit has a unique inverter bridge; or, each inverter unit is composed of multiple inverter bridges, and the DC sides and the AC sides of the multiple inverter bridges are connected in parallel.
可选的，所述分裂变压器或所述两个独立变压器被一个所述串联型逆变系统独立使用，或者所述分裂变压器或所述两个独立变压器被多个所述串联型逆变系统共用。Optionally, the split transformer or the two independent transformers are used independently by one of the series inverter systems, or the split transformer or the two independent transformers are shared by a plurality of the series inverter systems .
可选的，所述输入源的正、负极为光伏组串汇流箱的输出正、负极，或者是储能电池的正、负极，或者是DC/DC变换器的输出正、负极。Optionally, the positive and negative electrodes of the input source are the output positive and negative electrodes of the photovoltaic string combiner box, or the positive and negative electrodes of the energy storage battery, or the output positive and negative electrodes of the DC/DC converter.
一种串联型逆变系统的保护方法，其中：A protection method for a series inverter system, wherein:
所述串联型逆变系统包括主电路和保护电路；The series inverter system includes a main circuit and a protection circuit;
所述主电路包括：两个逆变单元；所述两个逆变单元的直流侧相串联后引出一根正线和一根负线，分别接入输入源的正极和负极；所述两个逆变单元直 流侧串联后的中点以及所述输入源的中点通过接地单元接地或直接接地；所述两个逆变单元的交流侧分别接入分裂变压器低压侧的两个分裂绕组或者分别接入两个独立变压器低压侧的绕组；The main circuit includes: two inverter units; the DC sides of the two inverter units are connected in series and then lead out a positive line and a negative line, which are respectively connected to the positive and negative electrodes of the input source; the two The midpoint of the series-connected DC side of the inverter units and the midpoint of the input source are grounded or directly grounded through the grounding unit; the AC sides of the two inverter units are respectively connected to the two split windings on the low-voltage side of the split transformer or are Access the windings on the low-voltage side of two independent transformers;
所述保护电路包括双向可控的开关电路；所述双向可控的开关电路串联在所述两个逆变单元直流侧串联后的中点引出线上；The protection circuit includes a bidirectionally controllable switch circuit; the bidirectionally controllable switch circuit is connected in series on the midpoint lead-out line after the DC sides of the two inverter units are connected in series;
所述保护方法包括：The protection method includes:
检测所述双向可控的开关电路上的电流大小；detecting the magnitude of the current on the bidirectionally controllable switch circuit;
当所述双向可控的开关电路上的电流超过阈值时，控制所述双向可控的开关电路与当前故障电流方向同向的导通路径断开，或者控制所述双向可控的开关电路双向导通的路径同时断开。When the current on the bidirectionally controllable switch circuit exceeds a threshold value, the bidirectionally controllable switch circuit is controlled to be disconnected from the conduction path in the same direction as the current fault current, or the bidirectionally controllable switch circuit is controlled to be bidirectional Conducted paths are simultaneously disconnected.
从上述的技术方案可以看出，当串联型逆变系统正常工作时，双向可控的开关电路上电流为零或很小。而当出现故障时，例如所述正线或负线对地短路，或者所述正、负线中的一根对地阻抗过低，或者两个逆变单元之间功率严重不均衡时，所述双向可控的开关电路上会有大电流流过，电流变化明显，那么当检测到流过所述双向可控的开关电路的电流超过一定阈值时，便知此时必是发生了故障，立即断开所述双向可控的开关电路的单向导通路径或双向导通路径，即可切断故障电流，迅速实现保护。It can be seen from the above technical solutions that when the series inverter system works normally, the current on the bidirectionally controllable switching circuit is zero or very small. When a fault occurs, for example, the positive line or the negative line is short-circuited to ground, or the impedance of one of the positive and negative lines to ground is too low, or the power between the two inverter units is seriously unbalanced, the There will be a large current flowing through the bidirectionally controllable switching circuit, and the current changes significantly, then when it is detected that the current flowing through the bidirectionally controllable switching circuit exceeds a certain threshold, it is known that a fault must have occurred at this time. The one-way conduction path or the two-way conduction path of the bidirectionally controllable switch circuit is immediately disconnected, so that the fault current can be cut off and protection can be realized quickly.
附图说明Description of drawings
为了更清楚地说明本发明实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative efforts.
图1为现有技术公开的一种串联型逆变系统结构示意图；1 is a schematic structural diagram of a series inverter system disclosed in the prior art;
图2为图1所示串联型逆变系统中正线对地短路的示意图；FIG. 2 is a schematic diagram of a positive line-to-ground short circuit in the series inverter system shown in FIG. 1;
图3为本发明实施例公开的一种串联型逆变系统结构示意图；3 is a schematic structural diagram of a series inverter system disclosed in an embodiment of the present invention;
图4为图3所示串联型逆变系统中正线对地短路的示意图；FIG. 4 is a schematic diagram of a positive line-to-ground short circuit in the series inverter system shown in FIG. 3;
图5为图3所示串联型逆变系统中负线对地短路的示意图；FIG. 5 is a schematic diagram of the negative line-to-ground short circuit in the series inverter system shown in FIG. 3;
图6a为本发明实施例公开的一种双向可控的开关电路结构示意图；6a is a schematic structural diagram of a bidirectional controllable switch circuit disclosed in an embodiment of the present invention;
图6b为本发明实施例公开的又一种双向可控的开关电路结构示意图；6b is a schematic structural diagram of another bidirectional controllable switch circuit disclosed in an embodiment of the present invention;
图6c为本发明实施例公开的又一种双向可控的开关电路结构示意图；FIG. 6c is a schematic structural diagram of another bidirectional controllable switch circuit disclosed in an embodiment of the present invention;
图6d为本发明实施例公开的又一种双向可控的开关电路结构示意图；6d is a schematic structural diagram of another bidirectional controllable switch circuit disclosed in an embodiment of the present invention;
图7为本发明实施例公开的一种串联型逆变系统的保护方法流程图。FIG. 7 is a flowchart of a protection method for a series inverter system disclosed in an embodiment of the present invention.
具体实施方式Detailed ways
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.
参见图3，本发明实施例公开了一种串联型逆变系统，包括主电路和保护电路；Referring to FIG. 3, an embodiment of the present invention discloses a series inverter system, including a main circuit and a protection circuit;
所述主电路包括：两个逆变单元；The main circuit includes: two inverter units;
所述两个逆变单元的直流侧相串联后引出一根正线和一根负线，分别接入输入源的正极和负极；所述输入源的正、负极为光伏组串汇流箱的输出正、负极，或者是储能电池的正、负极，或者是DC/DC变换器的输出正、负极等，并不局限；After the DC sides of the two inverter units are connected in series, a positive line and a negative line are drawn out, which are respectively connected to the positive and negative electrodes of the input source; the positive and negative electrodes of the input source are the output of the photovoltaic string combiner box The positive and negative poles, or the positive and negative poles of the energy storage battery, or the output positive and negative poles of the DC/DC converter, are not limited;
所述两个逆变单元的直流侧串联后的中点以及所述输入源的中点通过接地单元接地或直接接地，此时两中点对地电压基本为零，相当于两中点之间有一根虚拟连接的中线(当然也可以将该虚拟连接的中线实体化，即将两中点真正用一根线缆连接起来)；The midpoint of the DC side of the two inverter units connected in series and the midpoint of the input source are grounded or directly grounded through the grounding unit. At this time, the voltage between the two midpoints to the ground is basically zero, which is equivalent to the difference between the two midpoints. There is a virtually connected midline (of course, the virtually connected midline can also be materialized, that is, the two midpoints are actually connected by a cable);
所述两个逆变单元的交流侧分别接入分裂变压器低压侧的两个分裂绕组，所述分裂变压器的高压侧接入大电网或负载(或所述两个逆变单元的交流侧分别接入两个独立变压器低压侧的绕组，这两个独立变压器的高压侧并联后接入大电网或负载)；The AC sides of the two inverter units are respectively connected to the two split windings on the low voltage side of the split transformer, and the high voltage side of the split transformer is connected to the large power grid or load (or the AC sides of the two inverter units are respectively connected to the two split windings). into the windings of the low-voltage side of two independent transformers, and the high-voltage sides of the two independent transformers are connected in parallel to the large power grid or load);
所述保护电路包括：控制单元(图中未示出)和双向可控的开关电路；The protection circuit includes: a control unit (not shown in the figure) and a bidirectional controllable switch circuit;
所述双向可控的开关电路串联在所述两个逆变单元的直流侧串联后的中 点引出线(即所述两个逆变单元的直流侧的汇流处)；The bidirectional controllable switch circuit is connected in series with the midpoint lead-out line after the DC sides of the two inverter units are connected in series (that is, the confluence of the DC sides of the two inverter units);
所述控制单元用于在检测到所述双向可控的开关电路上的电流超过阈值时，控制所述双向可控的开关电路与当前故障电流方向同向的导通路径断开，或者控制所述双向可控的开关电路双向导通的路径同时断开。The control unit is configured to, when detecting that the current on the bidirectionally controllable switch circuit exceeds a threshold, control the bidirectionally controllable switch circuit to disconnect from the conduction path in the same direction as the current fault current, or control all The bidirectional conduction path of the bidirectionally controllable switch circuit is simultaneously disconnected.
下面，对上述串联型逆变系统的工作原理进行详述。Hereinafter, the working principle of the above-mentioned series inverter system will be described in detail.
为便于描述，将上述串联型逆变系统中引出所述正线的逆变单元称为逆变单元1，将引出所述负线的逆变单元称为逆变单元2；For the convenience of description, the inverter unit leading out the positive line in the above series inverter system is referred to as inverter unit 1, and the inverter unit leading out the negative line is referred to as inverter unit 2;
仍参见图3，当所述串联型逆变系统正常工作时，所述双向可控的开关电路处于双向导通状态，理想状态下所述正线上的电流I1与所述负线上的电流I2大小相等，电流I1、I2的流向如图3中箭头所示，此时所述中线上没有电流流过；不过实际应用时逆变单元1与逆变单元2的功率难免存在一些细微偏差，此时所述正线上的电流I1与所述负线上的电流I2不平衡，所述中线上有电流流过，其电流大小等于|I1-I2|，|I1-I2|比I1、I2要小得多。Still referring to FIG. 3 , when the series inverter system works normally, the bidirectionally controllable switch circuit is in a bidirectional conduction state, and in an ideal state, the current I1 on the positive line and the current on the negative line I2 is equal in size, and the currents I1 and I2 flow as shown by the arrows in Figure 3. At this time, there is no current flowing on the neutral line; however, in practical applications, the power of inverter unit 1 and inverter unit 2 will inevitably have some slight deviations. At this time, the current I1 on the positive line is unbalanced with the current I2 on the negative line, and there is a current flowing on the neutral line, and the magnitude of the current is equal to |I1-I2|, and |I1-I2| much smaller.
由于中线对地电压基本为零，所以：Since the neutral-to-ground voltage is basically zero, so:
一旦所述正线对地短路，会使得逆变单元1的直流母线能量和交流侧能量均灌入短路点，形成如图4所示短路电流I3，此时流过所述双向可控的开关电路的总电流等于I3+I2，I3+I2远远大于|I1-I2|；同样的，一旦所述负线对地短路，会使得逆变单元2的直流母线能量和交流侧能量均灌入短路点，形成如图5所示短路电流I4，此时流过所述双向可控的开关电路的总电流等于I4+I1，I4+I1远远大于|I1-I2|；Once the positive line is short-circuited to the ground, both the DC bus energy and the AC side energy of the inverter unit 1 will be injected into the short-circuit point, forming a short-circuit current I3 as shown in Figure 4, which flows through the bidirectional controllable switch at this time. The total current of the circuit is equal to I3+I2, and I3+I2 is much larger than |I1-I2|; in the same way, once the negative line is short-circuited to the ground, both the DC bus energy and the AC side energy of the inverter unit 2 will be injected into At the short-circuit point, a short-circuit current I4 is formed as shown in Figure 5. At this time, the total current flowing through the bidirectionally controllable switching circuit is equal to I4+I1, and I4+I1 is much larger than |I1-I2|;
一旦所述正线对地阻抗过低，会使得逆变单元1的直流母线能量和交流侧能量均灌入低阻抗点，形成与图4中I3同向的电流，记为I5，此时流过所述双向可控的开关电路的总电流等于I5+I2-I1，I5+I2-I1远远大于|I1-I2|；一旦所述负线对地阻抗过低，会使得逆变单元2的直流母线能量和交流侧能量均灌入低阻抗点，形成与图5中I4同向的电流，记为I6，此时流过所述双向可控的开关电路的总电流等于I6+I1-I2，I6+I1-I2远远大于|I1-I2|。Once the impedance of the positive line to ground is too low, both the DC bus energy and the AC side energy of the inverter unit 1 will be injected into the low impedance point, forming a current in the same direction as I3 in Figure 4, which is recorded as I5. The total current passing through the bidirectional controllable switch circuit is equal to I5+I2-I1, and I5+I2-I1 is much larger than |I1-I2|; once the impedance of the negative line to ground is too low, the inverter unit 2 Both the DC bus energy and the AC side energy are poured into the low impedance point, forming a current in the same direction as I4 in Figure 5, denoted as I6, and the total current flowing through the bidirectionally controllable switching circuit at this time is equal to I6+I1- I2, I6+I1-I2 are much larger than |I1-I2|.
一旦逆变单元1的功率远大于逆变单元2，会使得所述双向可控的开关电路上流过电流|I1-I2|远大于0；同理，一旦逆变单元2的功率远大于逆变单元1， 会使得所述双向可控的开关电路上流过电流|I1-I2|远大于0。Once the power of the inverter unit 1 is much larger than that of the inverter unit 2, the bidirectional controllable switch circuit will cause the current |I1-I2| In unit 1, the current |I1-I2| flowing through the bidirectionally controllable switch circuit is much greater than 0.
所述控制单元在检测到流过所述双向可控的开关电路的电流超过一定阈值时，知晓此时必是发生了故障，立即断开所述双向可控的开关电路与当前故障电流方向同向的导通路径，或者也可以同时断开所述双向可控的开关电路双向导通的路径，从而切断当前故障电路，迅速实现保护。When the control unit detects that the current flowing through the two-way controllable switch circuit exceeds a certain threshold, it knows that a fault must have occurred at this time, and immediately disconnects the two-way controllable switch circuit in the same direction as the current fault current. The bidirectional conduction path of the bidirectional controllable switch circuit can also be disconnected at the same time, so as to cut off the current fault circuit and realize the protection quickly.
综上所述，当串联型逆变系统正常工作时，双向可控的开关电路上电流为零或很小。而当出现故障时，例如所述正线或负线对地短路时，或者所述正、负线中的一根对地阻抗过低，或者两个逆变单元之间功率严重不均衡时，所述双向可控的开关电路上会有大电流流过，电流变化明显，那么当检测到流过所述双向可控的开关电路的电流超过一定阈值时，便知此时必是发生了故障，立即断开所述双向可控的开关电路的单向导通路径或双向导通路径，即可切断故障电流，迅速实现保护。To sum up, when the series inverter system works normally, the current on the bidirectional controllable switching circuit is zero or very small. When a fault occurs, for example, the positive line or the negative line is short-circuited to ground, or the impedance of one of the positive and negative lines to ground is too low, or the power between the two inverter units is seriously unbalanced, There will be a large current flowing through the bidirectionally controllable switch circuit, and the current changes significantly, then when it is detected that the current flowing through the bidirectionally controllable switching circuit exceeds a certain threshold, it will be known that a fault must have occurred at this time. , immediately disconnect the one-way conduction path or the two-way conduction path of the bidirectionally controllable switch circuit, so as to cut off the fault current and realize the protection quickly.
所述双向可控的开关电路具有从左向右、从右向左两条导通路径，并且两条导通路径的通断状态均可控。所述双向可控的开关电路可以为一个独立功率半导体器件，例如逆导型IGBT(Insulated Gate Bipolar Transistor，绝缘栅双极晶体管)；或者，所述双向可控的开关电路也可以包括多个功率半导体器件。可选的，当所述双向可控的开关电路包括多个功率半导体器件时，其有多种可选的拓扑结构，以下仅给出4个示例。The bidirectionally controllable switch circuit has two conduction paths from left to right and from right to left, and the on-off states of the two conduction paths are controllable. The bidirectionally controllable switch circuit may be an independent power semiconductor device, such as a reverse conducting IGBT (Insulated Gate Bipolar Transistor, insulated gate bipolar transistor); or, the bidirectionally controllable switch circuit may also include a plurality of power Semiconductor device. Optionally, when the bidirectionally controllable switch circuit includes multiple power semiconductor devices, there are multiple optional topological structures, and only four examples are given below.
示例1、所述双向可控的开关电路包括：两个反向串联的MOSFET(Metal-Oxide-Semiconductor Field-Effect Transistor，金属氧化物半导体场效应晶体管)。例如图6a所示，图6a中用Q1、Q2分别表示所述两个MOSFET，Q1的漏极接Q2的漏极；当Q1导通、Q2截止时，双向可控的开关电路从右往左的方向导通、从左往右的方向截止；当Q2导通、Q1截止时，双向可控的开关电路从右往左的方向截止、从左往右的方向导通。Example 1. The bidirectionally controllable switch circuit includes: two MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistor, metal-oxide-semiconductor field-effect transistors) connected in series in opposite directions. For example, as shown in Figure 6a, in Figure 6a, Q1 and Q2 are used to represent the two MOSFETs, respectively, and the drain of Q1 is connected to the drain of Q2; when Q1 is turned on and Q2 is turned off, the bidirectional controllable switching circuit is from right to left. When Q2 is turned on and Q1 is turned off, the bidirectional controllable switch circuit is turned off from right to left and turned on from left to right.
示例2、所述双向可控的开关电路包括：两个反向串联的IGBT，并且每个IGBT上各反向并联一个二极管。例如图6b所示，图6b中用Q3、Q4分别表示所述两个IGBT，Q3的发射极接Q4的发射极；当Q3导通、Q4截止时， 双向可控的开关电路从右往左的方向截止、从左往右的方向导通；当Q4导通、Q3截止时，双向可控的开关电路从右往左的方向导通、从左往右的方向截止。Example 2. The bidirectionally controllable switching circuit includes: two IGBTs connected in reverse series, and each IGBT is connected in reverse parallel with a diode. For example, as shown in Figure 6b, in Figure 6b, Q3 and Q4 are used to represent the two IGBTs, respectively, and the emitter of Q3 is connected to the emitter of Q4; when Q3 is turned on and Q4 is turned off, the bidirectional controllable switching circuit is from right to left. When Q4 is turned on and Q3 is turned off, the bidirectional controllable switch circuit is turned on from right to left and turned off from left to right.
示例3、所述双向可控的开关电路包括：一个MOSFET和一个IGBT，所述MOSFET和所述IGBT反向串联，并且所述IGBT上反向并联一个二极管。例如图6c所示，图6c中用Q5、Q6分别表示所述MOSFET、IGBT，Q5的漏极接Q6的集电极；当Q5导通、Q6截止时，双向可控的开关电路从右往左的方向导通、从左往右的方向截止；当Q6导通、Q5截止时，双向可控的开关电路从右往左的方向截止、从左往右的方向导通。Example 3. The bidirectionally controllable switching circuit includes: a MOSFET and an IGBT, the MOSFET and the IGBT are connected in series in reverse, and the IGBT is connected in parallel with a diode. For example, as shown in Figure 6c, in Figure 6c, Q5 and Q6 are used to represent the MOSFET and IGBT, respectively, and the drain of Q5 is connected to the collector of Q6; when Q5 is turned on and Q6 is turned off, the bidirectional controllable switching circuit is from right to left. When Q6 is turned on and Q5 is turned off, the bidirectional controllable switch circuit is turned off from right to left and turned on from left to right.
示例4、所述双向可控的开关电路包括：两个反极性串联的二极管，并且每个二极管上各并联一个电磁式开关电器。例如图6d所示，图6d中D1、D2分别表示所述两个二极管，D1的阳极接D2的阳极，K1、K2分别表示D1、D2上并联的电磁式开关电器；当K1开通、K2关断时，双向可控的开关电路从右往左的方向截止、从左往右的方向导通；当K2开通、K1关断时，双向可控的开关电路从右往左的方向导通、从左往右的方向截止。所述电磁式开关电器例如为继电器或接触器等。Example 4. The bidirectionally controllable switching circuit includes: two diodes connected in series with opposite polarities, and each diode is connected in parallel with an electromagnetic switching device. For example, as shown in Fig. 6d, D1 and D2 in Fig. 6d represent the two diodes respectively, the anode of D1 is connected to the anode of D2, and K1 and K2 respectively represent the electromagnetic switching devices connected in parallel on D1 and D2; when K1 is turned on and K2 is turned off When the switch is turned off, the bidirectional controllable switch circuit is turned off from right to left and turned on from left to right; when K2 is turned on and K1 is turned off, the bidirectional controllable switch circuit is turned on from right to left, Cut off from left to right. The electromagnetic switchgear is, for example, a relay or a contactor.
可选的，在上述公开的任一实施例中，每个逆变单元均具有唯一的逆变桥；或者，每个逆变单元均由多个逆变桥组成，所述多个逆变桥的直流侧并联、交流侧并联。Optionally, in any of the embodiments disclosed above, each inverter unit has a unique inverter bridge; or, each inverter unit is composed of multiple inverter bridges, and the multiple inverter bridges The DC side is connected in parallel and the AC side is connected in parallel.
可选的，在上述公开的任一实施例中，所述分裂变压器或所述两个独立变压器被一个所述串联型逆变系统独立使用，或者所述分裂变压器或所述两个独立变压器被多个所述串联型逆变系统共用。Optionally, in any of the embodiments disclosed above, the split transformer or the two independent transformers are used independently by one of the series inverter systems, or the split transformer or the two independent transformers are used independently. A plurality of the series inverter systems are shared.
与上述实施例相对应的，本发明实施例还公开了一种串联型逆变系统的保护方法，所述串联型逆变系统包括主电路和保护电路；Corresponding to the above embodiment, the embodiment of the present invention further discloses a protection method for a series inverter system, wherein the series inverter system includes a main circuit and a protection circuit;
所述主电路包括：两个逆变单元；所述两个逆变单元的直流侧相串联后引出一根正线和一根负线，分别接入输入源的正极和负极；所述两个逆变单元直流侧串联后的中点以及所述输入源的中点均通过接地单元接地或均直接接地； 所述两个逆变单元的交流侧分别接入分裂变压器低压侧的两个分裂绕组或者分别接入两个独立变压器低压侧的绕组；The main circuit includes: two inverter units; the DC sides of the two inverter units are connected in series and then lead out a positive line and a negative line, which are respectively connected to the positive and negative electrodes of the input source; the two The midpoint of the series-connected DC side of the inverter units and the midpoint of the input source are both grounded through the grounding unit or both are directly grounded; the AC sides of the two inverter units are respectively connected to the two split windings on the low voltage side of the split transformer Or connect to the windings on the low-voltage side of two independent transformers respectively;
所述保护电路包括双向可控的开关电路；所述双向可控的开关电路串联在所述两个逆变单元直流侧串联后的中点引出线上；The protection circuit includes a bidirectionally controllable switch circuit; the bidirectionally controllable switch circuit is connected in series on the midpoint lead-out line after the DC sides of the two inverter units are connected in series;
如图7所示，所述保护方法包括：As shown in Figure 7, the protection method includes:
步骤S01：检测所述双向可控的开关电路上的电流大小；Step S01: detecting the magnitude of the current on the bidirectionally controllable switch circuit;
步骤S02：判断所述双向可控的开关电路上的电流是否超过阈值，若是，进入步骤S03，若否，返回步骤S01；Step S02: judging whether the current on the bidirectionally controllable switch circuit exceeds a threshold value, if yes, go to Step S03, if not, go back to Step S01;
步骤S03：控制所述双向可控的开关电路与当前故障电流方向同向的导通路径断开，或者控制所述双向可控的开关电路双向导通的路径同时断开。Step S03 : control the bidirectionally controllable switch circuit to disconnect from the conduction path in the same direction of the current fault current, or control the bidirectionally controllable switch circuit to simultaneously disconnect the bidirectional conduction path.
本说明书中各个实施例采用递进的方式描述，每个实施例重点说明的都是与其他实施例的不同之处，各个实施例之间相同相似部分互相参见即可。对于实施例公开的保护方法而言，由于其与实施例公开的保护电路相对应，所以描述的比较简单，相关之处参见保护电路部分说明即可。The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the various embodiments can be referred to each other. As for the protection method disclosed in the embodiment, since it corresponds to the protection circuit disclosed in the embodiment, the description is relatively simple, and the relevant part can be referred to the description of the protection circuit.
本发明的说明书和权利要求书及上述附图中的术语“第一”、“第二”等是用于区别类似的不同对象，而不必用于描述特定的顺序或先后次序。而且，术语“包括”、“包含”或者其任何其他变体意在涵盖非排他性的包含，从而使得包括一系列要素的过程、方法、商品或者设备不仅包括那些要素，而且还包括没有明确列出的其他要素，或者是还包括为这种过程、方法、商品或者设备所固有的要素。在没有更多限制的情况下，由语句“包括一个”限定的要素，并不排除在包括要素的过程、方法、商品或者设备中还存在另外的相同要素。The terms "first", "second" and the like in the description and claims of the present invention and the above drawings are used to distinguish similar different objects, and are not necessarily used to describe a specific order or sequence. Furthermore, the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article of manufacture or device comprising a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, commodity or apparatus. Without further limitation, an element qualified by the phrase "comprising a" does not preclude the presence of additional identical elements in the process, method, article of manufacture, or device that includes the element.
对所公开的实施例的上述说明，使本领域专业技术人员能够实现或使用本发明。对这些实施例的多种修改对本领域的专业技术人员来说将是显而易见的，本文中所定义的一般原理可以在不脱离本发明实施例的精神或范围的情况下，在其它实施例中实现。因此，本发明实施例将不会被限制于本文所示的这些实施例，而是要符合与本文所公开的原理和新颖特点相一致的最宽的范围。The above description of the disclosed embodiments enables any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the embodiments of the present invention . Thus, embodiments of the present invention are not to be limited to those shown herein, but are to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (11)

  1. 一种串联型逆变系统，其特征在于，包括主电路和保护电路；A series inverter system is characterized in that it includes a main circuit and a protection circuit;
    所述主电路包括：两个逆变单元；所述两个逆变单元的直流侧相串联后引出一根正线和一根负线，分别接入输入源的正极和负极；所述两个逆变单元直流侧串联后的中点以及所述输入源的中点通过接地单元接地或直接接地；所述两个逆变单元的交流侧分别接入分裂变压器低压侧的两个分裂绕组或者分别接入两个独立变压器低压侧的绕组；The main circuit includes: two inverter units; the DC sides of the two inverter units are connected in series and then lead out a positive line and a negative line, which are respectively connected to the positive and negative electrodes of the input source; the two The midpoint of the series-connected DC side of the inverter units and the midpoint of the input source are grounded or directly grounded through the grounding unit; the AC sides of the two inverter units are respectively connected to the two split windings on the low-voltage side of the split transformer or are Access the windings on the low-voltage side of two independent transformers;
    所述保护电路包括：控制单元和双向可控的开关电路；所述双向可控的开关电路串联在所述两个逆变单元直流侧串联后的中点引出线上；所述控制单元用于在检测到所述双向可控的开关电路上的电流超过阈值时，控制所述双向可控的开关电路与当前故障电流方向同向的导通路径断开，或者控制所述双向可控的开关电路双向导通的路径同时断开。The protection circuit includes: a control unit and a bidirectionally controllable switch circuit; the bidirectionally controllable switch circuit is connected in series on the midpoint lead-out line after the DC side of the two inverter units are connected in series; the control unit is used for When detecting that the current on the bidirectionally controllable switch circuit exceeds a threshold value, control the bidirectionally controllable switch circuit to disconnect from the conduction path with the same direction as the current fault current, or control the bidirectionally controllable switch The paths that conduct the circuit in both directions are disconnected at the same time.
  2. 根据权利要求1所述的串联型逆变系统，其特征在于，所述双向可控的开关电路包括至少一个功率半导体器件。The series inverter system according to claim 1, wherein the bidirectionally controllable switch circuit comprises at least one power semiconductor device.
  3. 根据权利要求2所述的串联型逆变系统，其特征在于，所述双向可控的开关电路包括：两个反向串联的MOSFET。The series inverter system according to claim 2, wherein the bidirectionally controllable switch circuit comprises: two MOSFETs connected in series in opposite directions.
  4. 根据权利要求2所述的串联型逆变系统，其特征在于，所述双向可控的开关电路包括：两个反向串联的IGBT，并且每个IGBT上各反向并联一个二极管。The series inverter system according to claim 2, wherein the bidirectionally controllable switch circuit comprises: two IGBTs connected in reverse series, and each IGBT is connected in reverse parallel with a diode.
  5. 根据权利要求2所述的串联型逆变系统，其特征在于，所述双向可控的开关电路包括：一个MOSFET和一个IGBT，所述MOSFET和所述IGBT反向串联，并且所述IGBT上反向并联一个二极管。The series inverter system according to claim 2, wherein the bidirectionally controllable switch circuit comprises: a MOSFET and an IGBT, the MOSFET and the IGBT are connected in reverse series, and the IGBT is reversed in series. Connect a diode in parallel.
  6. 根据权利要求2所述的串联型逆变系统，其特征在于，所述双向可控的开关电路包括：两个反向串联的二极管，并且每个二极管上各并联一个电磁式开关电器。The series inverter system according to claim 2, wherein the bidirectionally controllable switching circuit comprises: two diodes connected in reverse series, and each diode is connected in parallel with an electromagnetic switching device.
  7. 根据权利要求2所述的串联型逆变系统，其特征在于，所述双向可控的开关电路为逆导型IGBT。The series inverter system according to claim 2, wherein the bidirectionally controllable switch circuit is a reverse conduction IGBT.
  8. 根据权利要求1所述的串联型逆变系统，其特征在于，每个逆变单元均具有唯一的逆变桥；或者，每个逆变单元均由多个逆变桥组成，所述多个逆 变桥的直流侧并联、交流侧并联。The series inverter system according to claim 1, wherein each inverter unit has a unique inverter bridge; or, each inverter unit is composed of a plurality of inverter bridges, the plurality of The DC side of the inverter bridge is connected in parallel, and the AC side is connected in parallel.
  9. 根据权利要求1所述的串联型逆变系统，其特征在于，所述分裂变压器或所述两个独立变压器被一个所述串联型逆变系统独立使用，或者所述分裂变压器或所述两个独立变压器被多个所述串联型逆变系统共用。The series inverter system according to claim 1, wherein the split transformer or the two independent transformers are used independently by one of the series inverter systems, or the split transformer or the two independent transformers are used independently. An independent transformer is shared by a plurality of the series inverter systems.
  10. 根据权利要求1所述的串联型逆变系统，其特征在于，所述输入源的正、负极为光伏组串汇流箱的输出正、负极，或者是储能电池的正、负极，或者是DC/DC变换器的输出正、负极。The series inverter system according to claim 1, wherein the positive and negative electrodes of the input source are the output positive and negative electrodes of the photovoltaic string combiner box, or the positive and negative electrodes of the energy storage battery, or the DC The output positive and negative poles of the /DC converter.
  11. 一种串联型逆变系统的保护方法，其特征在于：A protection method for a series inverter system, characterized in that:
    所述串联型逆变系统包括主电路和保护电路；The series inverter system includes a main circuit and a protection circuit;
    所述主电路包括：两个逆变单元；所述两个逆变单元的直流侧相串联后引出一根正线和一根负线，分别接入输入源的正极和负极；所述两个逆变单元直流侧串联后的中点以及所述输入源的中点通过接地单元接地或直接接地；所述两个逆变单元的交流侧分别接入分裂变压器低压侧的两个分裂绕组或者分别接入两个独立变压器低压侧的绕组；The main circuit includes: two inverter units; the DC sides of the two inverter units are connected in series and then lead out a positive line and a negative line, which are respectively connected to the positive and negative electrodes of the input source; the two The midpoint of the series-connected DC side of the inverter units and the midpoint of the input source are grounded or directly grounded through the grounding unit; the AC sides of the two inverter units are respectively connected to the two split windings on the low-voltage side of the split transformer or are Access the windings on the low-voltage side of two independent transformers;
    所述保护电路包括双向可控的开关电路；所述双向可控的开关电路串联在所述两个逆变单元直流侧串联后的中点引出线上；The protection circuit includes a bidirectionally controllable switch circuit; the bidirectionally controllable switch circuit is connected in series on the midpoint lead-out line after the DC sides of the two inverter units are connected in series;
    所述保护方法包括：The protection method includes:
    检测所述双向可控的开关电路上的电流大小；detecting the magnitude of the current on the bidirectionally controllable switch circuit;
    当所述双向可控的开关电路上的电流超过阈值时，控制所述双向可控的开关电路与当前故障电流方向同向的导通路径断开，或者控制所述双向可控的开关电路双向导通的路径同时断开。When the current on the bidirectionally controllable switch circuit exceeds a threshold value, the bidirectionally controllable switch circuit is controlled to be disconnected from the conduction path in the same direction as the current fault current, or the bidirectionally controllable switch circuit is controlled to be bidirectional Conducted paths are simultaneously disconnected.
PCT/CN2021/128032 2021-02-20 2021-11-02 Series-type inverter system and protection method therefor WO2022174623A1 (en)

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Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112953285B (en) * 2021-02-20 2024-05-14 阳光电源股份有限公司 Series inverter system and protection method thereof
CN113644629A (en) * 2021-07-19 2021-11-12 许继集团有限公司 Short-circuit protection device for rail transit traction power supply bidirectional converter system and control method thereof

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020101747A1 (en) * 2001-01-27 2002-08-01 Andreas Falk Medium frequency energy supply for rail vehicles
CN104218609A (en) * 2014-09-22 2014-12-17 周细文 Topological structure of photovoltaic power station system based on bipolar direct-current transmission
CN105472839A (en) * 2015-10-27 2016-04-06 杭州中恒派威电源有限公司 Two-path bidirectional switch direct frequency conversion three-phase power supply and communication device and control method thereof
CN111682510A (en) * 2020-05-18 2020-09-18 天津大学 First-removal and then-isolation protection method for ground fault of symmetrical unipolar direct-current microgrid
CN112953285A (en) * 2021-02-20 2021-06-11 阳光电源股份有限公司 Series inverter system and protection method thereof

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06327262A (en) * 1993-05-07 1994-11-25 Mitsubishi Electric Corp Protector for inverter
JP3993473B2 (en) * 2002-06-20 2007-10-17 株式会社ルネサステクノロジ Semiconductor integrated circuit device
US8212408B2 (en) * 2008-12-24 2012-07-03 Alencon Acquisition Co., Llc. Collection of electric power from renewable energy sources via high voltage, direct current systems with conversion and supply to an alternating current transmission network
DE102009052461A1 (en) * 2009-11-09 2011-05-26 Sma Solar Technology Ag Inverter circuitry
US20110241433A1 (en) * 2010-03-30 2011-10-06 General Electric Company Dc transmission system for remote solar farms
WO2013060354A1 (en) * 2011-10-24 2013-05-02 Siemens Aktiengesellschaft Converter for high-voltage dc transmission
US8749167B2 (en) * 2012-06-15 2014-06-10 Lightel Technologies, Inc. Linear solid-state lighting with voltage sensing mechanism free of fire and shock hazards
CN103248256A (en) * 2013-05-20 2013-08-14 合肥工业大学 Voltage-multiplying three-level photovoltaic grid-connected inverter with neutral point balance capability
CN109167390B (en) * 2018-09-21 2021-11-26 华为数字能源技术有限公司 Photovoltaic power generation inverter system
CN209562411U (en) * 2019-02-26 2019-10-29 深圳供电局有限公司 A kind of High Frequency Link bidirectional, dc transformer of two-way switch access
WO2021208044A1 (en) * 2020-04-16 2021-10-21 华为技术有限公司 Power supply system
CN111865132B (en) * 2020-08-26 2024-02-09 阳光电源（上海）有限公司 Single-phase inverter, inverter topology circuit and control method thereof

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020101747A1 (en) * 2001-01-27 2002-08-01 Andreas Falk Medium frequency energy supply for rail vehicles
CN104218609A (en) * 2014-09-22 2014-12-17 周细文 Topological structure of photovoltaic power station system based on bipolar direct-current transmission
CN105472839A (en) * 2015-10-27 2016-04-06 杭州中恒派威电源有限公司 Two-path bidirectional switch direct frequency conversion three-phase power supply and communication device and control method thereof
CN111682510A (en) * 2020-05-18 2020-09-18 天津大学 First-removal and then-isolation protection method for ground fault of symmetrical unipolar direct-current microgrid
CN112953285A (en) * 2021-02-20 2021-06-11 阳光电源股份有限公司 Series inverter system and protection method thereof

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