WO2022068531A1 - 一种级联式多端口变换器及三相中压输入系统 - Google Patents

一种级联式多端口变换器及三相中压输入系统 Download PDF

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Publication number
WO2022068531A1
WO2022068531A1 PCT/CN2021/116650 CN2021116650W WO2022068531A1 WO 2022068531 A1 WO2022068531 A1 WO 2022068531A1 CN 2021116650 W CN2021116650 W CN 2021116650W WO 2022068531 A1 WO2022068531 A1 WO 2022068531A1
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converter
input
low
voltage
units
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PCT/CN2021/116650
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English (en)
French (fr)
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庄加才
徐君
董钺
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阳光电源股份有限公司
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Priority to JP2022562780A priority Critical patent/JP2023521458A/ja
Priority to US18/029,401 priority patent/US20230387780A1/en
Priority to EP21874192.4A priority patent/EP4224692A1/en
Publication of WO2022068531A1 publication Critical patent/WO2022068531A1/zh

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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
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/21—Conversion of ac power input into dc 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
    • H02M7/217—Conversion of ac power input into dc 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
    • H02M7/2173—Conversion of ac power input into dc 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 in a biphase or polyphase circuit arrangement
    • 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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0067—Converter structures employing plural converter units, other than for parallel operation of the units on a single load
    • H02M1/0074—Plural converter units whose inputs are connected in series
    • 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
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/01—Resonant DC/DC converters
    • 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
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/285—Single converters with a plurality of output stages connected in parallel
    • 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
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33507—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters
    • H02M3/33523—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters with galvanic isolation between input and output of both the power stage and the feedback loop
    • 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
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33561—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having more than one ouput with independent control
    • 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
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
    • H02M3/33573—Full-bridge at primary side of an isolation transformer
    • 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
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
    • H02M3/33576—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements having at least one active switching element at the secondary side of an isolation transformer
    • H02M3/33584—Bidirectional converters
    • 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
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/21—Conversion of ac power input into dc 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
    • H02M7/217—Conversion of ac power input into dc 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
    • 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
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/21—Conversion of ac power input into dc 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
    • H02M7/217—Conversion of ac power input into dc 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
    • H02M7/219—Conversion of ac power input into dc 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 in a bridge configuration
    • 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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0067—Converter structures employing plural converter units, other than for parallel operation of the units on a single load
    • H02M1/007—Plural converter units in cascade
    • 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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0067—Converter structures employing plural converter units, other than for parallel operation of the units on a single load
    • H02M1/008—Plural converter units for generating at two or more independent and non-parallel outputs, e.g. systems with plural point of load switching regulators
    • 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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • H02M1/325—Means for protecting converters other than automatic disconnection with means for allowing continuous operation despite a fault, i.e. fault tolerant converters
    • 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
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac 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
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac 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
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac 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 with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac 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 with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load

Definitions

  • the present application relates to the technical field of power electronics, and more specifically, to a cascaded multi-port converter and a three-phase medium voltage input system.
  • Traditional DC charging piles generally first reduce the medium voltage to the mains voltage through a power frequency step-down transformer, such as 380V in China, and then convert the mains voltage into a DC voltage that can be used by electric vehicles through the power module, such as 200-1000Vdc, which is Electric vehicle charging; as shown in Figure 1, the primary winding of the power frequency voltage transformer is connected to the primary side high-voltage power supply, and the secondary winding of the power frequency transformer is respectively connected to the AC side of each DC charging pile module.
  • the DC side (Vout1, Vout2...Voutn shown in Figure 1) is connected to the charging port of the power module. Due to the requirements of safety regulations, in the case where multiple vehicles are allowed to charge at the same time, the input and output of the power module need to be isolated.
  • each DC charging pile module needs to be provided with the power frequency transformer, but also the DC charging pile.
  • the module also needs to be provided with an isolated DC/DC converter (isolated D/D as shown in Figure 1) at the rear stage of the AC/DC converter (A/D as shown in Figure 1); thus causing the scheme to exist at night. Defects such as self-loss and large size.
  • each module (module 1, module 2, ... module m shown in Figure 2) includes: a first AC /DC converters (A/D-P1, A/D-P1...A/D-Pm as shown in Figure 2), DC/AC converters (D/A-P1, D as shown in Figure 2 /A-P1...D/A-Pm), transformer and second AC/DC converter (A/D-S12, A/D-S22...A/D-Sm2 as shown in Fig.
  • each The output end of the module is connected in parallel to form a DC bus, and then connected to the charging port of the power module through each isolated DC/DC converter (isolated DC/DC1, isolated DC/DC2...isolated DC/DCn as shown in Figure 2); Since there needs to be isolation between the charging ports to ensure charging safety, in order to meet the input voltage requirements, a large number of modules are required to be cascaded, so that the output voltage of each cascaded module (ie the first AC/DC converter) In this scheme, the number of cascaded modules is large, which increases the volume, weight and cost of the converter.
  • embodiments of the present application provide a cascaded multi-port converter and a three-phase medium voltage input system, which are used to reduce the number of cascaded modules, thereby reducing the volume, weight and cost of the cascaded multi-port converter .
  • a first aspect of the present invention discloses a cascaded multi-port converter, comprising: a plurality of module units and a plurality of low-voltage rectifier units, the module units comprising: at least one multi-winding transformer and a plurality of high-voltage conversion units;
  • the input ends of each of the modular units are cascaded, and the two ends after the cascade are used as the two ports of the input ends of the cascaded multi-port converter;
  • the input ends of each of the high-voltage conversion units are cascaded, and the two ends after the cascade are used as the two input ports of the modular unit;
  • the magnetic core in the multi-winding transformer is wound with a plurality of primary windings and at least one secondary winding;
  • the output ends of each of the high-voltage conversion units are respectively connected with the corresponding primary windings;
  • the secondary windings are connected with the corresponding input ends of the corresponding low-voltage rectifier units .
  • the number of the low-voltage rectifier units is equal to the total number of all the secondary windings, and each of the secondary windings is connected to the input end of each of the low-voltage rectifier units in a one-to-one correspondence.
  • the number of the low-voltage rectifier units is less than the total number of all the secondary windings, and a plurality of independent secondary windings share the same low-voltage rectifier unit.
  • the multiple independent secondary windings include: secondary windings of different multi-winding transformers; and/or secondary windings on different magnetic columns in the same multi-winding transformer.
  • a plurality of independent secondary windings are connected in series to the input end of the common low-voltage rectifier unit, or connected in parallel to the input end of the common low-voltage rectifier unit.
  • the output ends of the corresponding low-voltage rectifier units are connected by a common bus, so that at least one of the multi-winding transformers has at least one secondary winding, which is respectively connected with at least one of the other multi-windings.
  • the corresponding secondary windings in the transformer There is an indirect connection relationship between the corresponding secondary windings in the transformer.
  • each of the multi-winding transformers there is at least one of the secondary windings, which are respectively connected with the corresponding secondary windings in the other multi-winding transformers through the corresponding low-voltage rectifier unit and the common bus.
  • the secondary windings are respectively connected with the corresponding secondary windings in the other multi-winding transformers through the corresponding low-voltage rectifier unit and the common bus.
  • each of the secondary windings connected to a common bus is also connected to an external power source through a common bus.
  • the secondary windings in each of the modular units are used for indirect common bus connection with other corresponding secondary windings.
  • it also includes: at least one additional redundant module unit;
  • Each secondary winding in the redundant module unit is independently output through the corresponding low-voltage rectifier unit.
  • it also includes: multiple multi-port multiplexing units;
  • Each input end of the multi-port multiplexing unit is respectively connected to the corresponding output end of different low-voltage rectifier units.
  • the multi-port multiplexing unit includes: a multi-input coupling branch, or a multi-input coupling branch and a converter at a subsequent stage.
  • the multi-input coupling branch is at least one of the following: a multi-input series structure, a multi-input parallel structure, and a multi-input series-parallel switching structure.
  • the multi-port multiplexing unit includes a multi-input coupling branch and a converter at a subsequent stage
  • the multi-input coupling branch includes the multi-input series-parallel switching structure:
  • the switches in the multi-input series-parallel switching structure are all bidirectional switches.
  • the bidirectional switch connected to the positive electrode or the negative electrode of the input terminal in the multi-input series-parallel switching structure is replaced by a diode.
  • the high-voltage conversion unit includes: a DC/AC converter and a first AC/DC converter;
  • the AC side of the first AC/DC converter is used as the input end of the high-voltage conversion unit;
  • the DC side of the first AC/DC converter is connected to the DC side of the DC/AC converter
  • the AC side of the DC/AC converter is used as the output end of the high voltage conversion unit.
  • the first AC/DC converter is a full-bridge structure or a half-bridge structure.
  • the low-voltage rectifier unit includes: a second AC/DC converter
  • the AC side of the second AC/DC converter is used as the input end of the low-voltage rectifier unit;
  • the DC side of the second AC/DC converter is used as the output end of the low-voltage rectifier unit.
  • the structure formed by the DC/AC converter through corresponding windings and the second AC/DC converter is any one of a dual active bridge structure, an LLC structure, and a CLLC structure.
  • the second aspect of the present invention discloses a three-phase medium voltage input system, comprising: three phase units, the phase units include: an inductor and the cascaded multi-port converter described in the first aspect of the present invention; wherein:
  • the head end of the input end of each of the phase units is connected to the medium voltage grid
  • the first end of the input end of the cascaded multi-port converter is connected to one end of the inductance; the other end of the inductance serves as the first end of the input end of the phase unit;
  • the input terminal of the multi-port converter is used as the input terminal of the phase unit.
  • a third aspect of the present invention discloses a three-phase medium voltage input system, comprising: an MMC converter and N DC conversion units, wherein the DC conversion units include: an inductor and the cascaded type of any one of the first aspect of the present invention Multi-port converter; N is a positive integer;
  • the head end of the input end of each of the DC conversion units is connected to the positive pole of the DC side of the MMC converter;
  • the tail end of the input end of each of the DC conversion units is connected to the negative electrode of the DC side of the MMC converter;
  • the AC side of the MMC converter is connected to the medium voltage grid
  • the first end of the input end of the cascaded multi-port converter is connected to one end of the inductor; the other end of the inductor serves as the first end of the input end of the DC conversion unit; the stage The tail end of the input end of the connected multi-port converter is used as the tail end of the input end of the DC conversion unit;
  • the first AC/DC converter of the cascaded multi-port converter in the DC conversion unit is replaced by two straight leads.
  • the input ends of each module unit are cascaded, and the two ends after the cascade are used as the two ports of the input end of the cascaded multi-port converter;
  • the input ends of each high-voltage conversion unit are cascaded, and the two ends after the cascade are used as the input ends of the module unit;
  • the output ends of each high-voltage conversion unit are respectively connected with the corresponding primary windings in each multi-winding transformer.
  • each secondary winding in each multi-winding transformer is used as the output end of the module unit, and is connected with the input end of the corresponding low-voltage rectifier unit; and the magnetic core in the multi-winding transformer is wound with a plurality of primary windings and Therefore, the windings of multiple high-voltage conversion units share the magnetic core, which can reduce the number of multi-winding transformers in the cascaded multi-port converter, and correspondingly reduce the number of low-voltage rectifier units; thus reducing the number of cascaded multi-port converters.
  • the size, weight and cost of the converter can reduce the number of multi-winding transformers in the cascaded multi-port converter, and correspondingly reduce the number of low-voltage rectifier units; thus reducing the number of cascaded multi-port converters.
  • FIG. 1 is a schematic diagram of a power supply module provided by an embodiment of the prior art
  • FIG. 2 is a schematic diagram of another power supply module provided by an embodiment of the prior art
  • FIG. 3 is a schematic diagram of a cascaded multi-port converter provided by an embodiment of the present invention.
  • FIG. 4 is a schematic diagram of another cascaded multi-port converter provided by an embodiment of the present invention.
  • FIG. 5 is a schematic diagram of another cascaded multi-port converter provided by an embodiment of the present invention.
  • FIG. 6 is a schematic diagram of another cascaded multi-port converter provided by an embodiment of the present invention.
  • FIG. 7a and 7b are schematic diagrams of two independent secondary windings being connected to the low-voltage rectifier unit;
  • FIGS. 8a to 8d are schematic diagrams of another cascaded multi-port converter provided by an embodiment of the present invention.
  • FIGS. 9a to 9c are schematic diagrams of a first AC/DC converter in another cascaded multi-port converter provided by an embodiment of the present invention.
  • 10a to 10c are schematic structural diagrams of a second AC/DC converter and a DC/AC converter in a cascaded multi-port converter provided by an embodiment of the present invention
  • FIG. 11a to 11f are schematic diagrams of a multi-port multiplexing unit in a cascaded multi-port converter according to an embodiment of the present invention.
  • 12a to 12c are schematic diagrams of another multi-port multiplexing unit in a cascaded multi-port converter provided by an embodiment of the present invention.
  • FIG. 13 is a schematic diagram of a three-phase medium voltage input system provided by an embodiment of the present invention.
  • FIG. 14 is a schematic diagram of another three-phase medium voltage input system provided by an embodiment of the present invention.
  • FIG. 15 is a schematic diagram of another cascaded multi-port converter provided by an embodiment of the present invention.
  • the terms “comprising”, “comprising” or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or device comprising a list of elements includes not only those elements, but also no Other elements expressly listed, or which are also inherent to such a process, method, article or apparatus.
  • an element qualified by the phrase “comprising a" does not preclude the presence of additional identical elements in a process, method, article or apparatus that includes the element.
  • Embodiments of the present invention provide a cascaded multi-port converter, which is used to solve the problems of the large number of cascaded modules in the prior art, which increases the volume, weight and cost of the converter.
  • the cascaded multi-port converter includes: a plurality of module units (module 1-module m shown in Figure 3) and a plurality of low-voltage rectifier units (A/M shown in Figure 3) D-S11 to A/D-S1n, A/D-S21 to A/D-S2n, and A/D-Sm1 to A/D-Smn), the modular unit includes: at least one multi-winding transformer and a plurality of high voltage Conversion unit (take the first high-voltage conversion unit in module 1 as an example, including A/D-P11 and D/A-P11 as shown in Figure 3).
  • each module unit is cascaded, and the two ends after the cascade are used as the two input ports of the cascaded multi-port converter. Specifically, as shown in Figure 3, the first end of the input end of the module 1 is used as the cascade connection.
  • the head end of the input end of the multi-port converter is connected to one end of the primary side high-voltage power supply
  • the tail end of the input end of module 1 is connected to the head end of the input end of module 2
  • the tail end of the input end of module 2 is connected to the head end of the input end of module 2
  • the head end of the input end of 3 is connected; and so on, the tail end of the input end of the module m-1 is connected with the head end of the input end of the module m, and the tail end of the input end of the module m is used as the input end of the cascaded multi-port converter.
  • the tail end of the input end is connected to the other end of the primary side high-voltage power supply.
  • the number m of the module units is not specifically limited here, and may be determined according to the actual situation, which is all within the protection scope of the present application.
  • the input ends of each high-voltage conversion unit are cascaded, and the two ends after the cascade are used as the input ends of the module unit;
  • the magnetic core in the multi-winding transformer is wound with a plurality of primary windings and at least one Secondary winding;
  • the output end of each high-voltage conversion unit is respectively connected with the corresponding primary winding in the corresponding multi-winding transformer;
  • the secondary winding is connected with the corresponding input end of the corresponding low-voltage rectifying unit.
  • the primary side of a multi-winding transformer can be connected to multiple high-voltage conversion units; the secondary side of a multi-winding transformer can also be connected to a low-voltage rectifier unit, or the secondary side of a multi-winding transformer can be connected to multiple A low-voltage rectifier unit is connected (as shown in FIG. 3 ); further, the voltage across the high-voltage conversion unit in the cascaded multi-port converter is controlled to be less than the corresponding threshold.
  • the module 1 in FIG. 3 includes: i high-voltage conversion units, and A/D-P1b and D/A-P1b form the b-th high-voltage conversion unit, wherein 0 ⁇ b ⁇ i.
  • the head end of the input end of the first high voltage conversion unit is used as the head end of the input end of the module 1, and the tail end of the input end of the first high voltage conversion unit is connected with the head end of the input end of the second high voltage conversion unit;
  • the tail end of the input end of the two high-voltage transformation units is connected to the head end of the input end of the third high-voltage transformation unit; and so on, the tail end of the input end of the i-1th high-voltage transformation unit is connected to the input end of the i-th high-voltage transformation unit.
  • the end and the head are connected;
  • the total number of high-voltage conversion units is i+j+...+k; in the prior art, the total number of high-voltage side cascaded units is s, and each high-voltage side cascaded unit Therefore, the total number of low-voltage side A/D units in the current technology is much larger than the total number of low-voltage rectifier units in this embodiment, and more transformers are needed; therefore, this embodiment A plurality of primary windings and a plurality of secondary windings are wound on the magnetic core of the multi-winding transformer, and the corresponding primary windings of the plurality of high-voltage conversion units share the magnetic core, and each group of low-voltage rectifier units is made by magnetic circuit coupling.
  • Both are coupled with high-voltage conversion units, and the energy of multiple high-voltage conversion units is interacted with the energy of multiple low-voltage rectifier units, which can reduce the number of multi-winding transformers in cascaded multi-port converters, and correspondingly reduce the number of low-voltage rectifier units. ; thereby reducing the volume, weight and cost of cascaded multi-port converters.
  • the number of low-voltage rectifier units and the total number of all secondary windings may be equal or not equal; here, the number of low-voltage rectifier units is equal to the total number of all secondary windings, respectively, And, the two cases where the number of low-voltage rectifier units is less than the total number of all secondary windings are explained:
  • the number of low-voltage rectifier units is equal to the total number of all secondary windings, and each secondary winding is connected to the input end of each low-voltage rectifier unit in a one-to-one correspondence.
  • each low-voltage rectifier unit is only connected to one secondary winding, that is, the secondary winding and the low-voltage rectifier unit are in a one-to-one relationship.
  • each The DC-AC side of the low-voltage rectifier unit serves as its own input end, and the DC side serves as its own output end (Vout11-Vout1n, Vout21-Vout2n, and Voutm1-Voutmn as shown in FIG. 3 ).
  • the number of low-voltage rectifier units is less than the total number of all secondary windings, and multiple independent secondary windings share the same low-voltage rectifier unit.
  • any two secondary windings are independent, it can be judged whether the two secondary windings will influence each other, if they influence each other, they are not independent, otherwise they are independent.
  • the secondary windings on the same magnetic column influence each other; that is, the secondary windings in different transformers do not affect each other and are independent, and the secondary windings on different magnetic columns in the same transformer do not affect each other. ,independent.
  • each module unit includes a multi-winding transformer, and the multi-winding transformer only includes one magnetic column; the secondary windings of different multi-winding transformers are independent of each other, such as Any secondary winding in module 1 is independent from the secondary windings in module 2 and module 3; the secondary windings in the same module unit are not independent; The secondary windings are not independent; that is, multiple independent secondary windings include: secondary windings of different multi-winding transformers; therefore, each independent secondary winding can share a low-voltage rectifier unit.
  • the secondary winding TX-S11 in module 1 and the secondary winding TX-S21 in module 2 share the low-voltage rectifier unit 11; the secondary winding TX-S12 in module 1 and the secondary winding TX-S21 in module 2
  • the side winding TX-S22 shares the low-voltage rectifier unit 12, and so on, the secondary winding TX-S1n in the module 1 and the secondary winding TX-S2n in the module 2 share the low-voltage rectifying unit 1n; and so on, the module
  • the secondary winding TX-Sx1 in module x and the secondary winding TX-Sm1 in module m share the low-voltage rectifier unit (0.5m)1; the secondary winding TX-Sx2 in module x and the secondary winding in module m
  • the winding TX-Sm2 shares the low-voltage rectifier unit (0.5m)2, and so on, the secondary winding TX-Sxn in module x and the secondary winding TX-S
  • Figure 4 shows two independent secondary windings sharing the same low-voltage rectifier unit as an example. Therefore, the number of low-voltage rectifier units is 0.5m, and the number of low-voltage rectifier units and the same low-voltage rectifier unit are shared.
  • the number of independent secondary windings of the unit is related. At this time, the number of independent secondary windings sharing the same low-voltage rectifier unit can be 2a, a is a positive integer, such as 2a is 2, 4, 6, 8, etc., the specific value of a is not specifically limited here , depending on the actual situation, all within the scope of protection of this application.
  • the number of independent secondary windings that share the same low-voltage rectifier unit may also be other values, which are not repeated here, but are all within the protection scope of the present application.
  • the secondary windings of different multi-winding transformers in the cascaded multi-port converter are mutually Independent; if the system where the cascaded multi-port converters are located includes at least two cascaded multi-port converters, and each cascaded multi-port converter is connected to the system in the same way, then the different cascaded multi-port converters are different.
  • the secondary windings of the multi-port converter are independent of each other, and the specific structures thereof will not be repeated here.
  • each module unit includes a multi-winding transformer, and the multi-winding transformer includes at least two magnetic columns; the secondary sides on different magnetic columns in the same multi-winding transformer
  • the windings are independent windings; for example, the secondary windings TX-SR11 to TX-SR1n on a magnetic column in module 1 interact with each other and are not independent; any one of the secondary windings TX-SR11 to TX-SR1n, and the module
  • the secondary windings TX-SL11 to TX-SL1n on another magnetic column in group 1, the secondary windings in modules 2 and 3 are independent, and the secondary windings on other magnetic columns are the same, and they will not be the same here.
  • the secondary winding TX-SR11 in module 1 and the secondary winding TX-SL11 in module 1 share the low-voltage rectifier unit 11; the secondary winding TX-SR12 in module 1 and the secondary winding in module 1
  • the side winding TX-SL12 shares the low voltage rectifier unit 12, and so on, the secondary side winding TX-SR1n in the module 1 and the secondary side winding TX-SL1n in the module 1 share the low voltage rectifier unit 1n.
  • the secondary winding TX-SR21 in module 2 and the secondary winding TX-SL21 in module 2 share the low-voltage rectifier unit 21; the secondary winding TX-SR22 in module 2 and the secondary winding TX in module 2 -SL22 shares the low-voltage rectifier unit 22, and so on, the secondary winding TX-SR2n in module 2 and the secondary winding TX-SL2n in module 2 share the low-voltage rectifier unit 2n; and so on, in module x
  • the secondary winding TX-SRx1 and the secondary winding TX-SLx1 in module x share the low-voltage rectifier unit x1; the secondary winding TX-SRx2 in module x and the secondary winding TX-SLx2 in module x share the low-voltage rectifier unit Unit x2, and so on, the secondary winding TX-SRxn in module x and the secondary winding TX-SLxn in module x share the low-voltage rectifier unit xn.
  • the secondary winding TX-SRm1 in module m and the secondary winding TX-SLm1 in module m share the low-voltage rectifier unit m1; the secondary winding TX-SRm2 in module m and the secondary winding TX in module m -SLm2 shares the low-voltage rectifier unit m2, and so on, the secondary winding TX-SRmn in the module m and the secondary winding TX-SLmn in the module m share the low-voltage rectifying unit mn.
  • Figure 5 shows two independent secondary windings sharing the same low-voltage rectifier unit as an example; at this time, the number of independent secondary windings sharing the same low-voltage rectifier unit can be 2a, and a is A positive integer, such as 2a is 2, 4, 6, 8, etc., the specific value of a is not specifically limited here, it can be determined according to the actual situation, and it is all within the protection scope of this application; of course, the same low voltage is shared.
  • the number of independent secondary windings of the rectifier unit may also be other values, which will not be repeated here, but are all within the protection scope of the present application.
  • each module unit has its own multi-winding transformer, and each multi-winding transformer includes at least two magnetic columns, then the level The connected multi-port converter includes at least two multi-winding transformers each containing at least two magnetic columns; the secondary windings on different magnetic columns in the same multi-winding transformer are independent windings; the secondary windings of different multi-winding transformers are Independent windings; for example, the secondary windings TX-SR11 to TX-SR1n in module 1 interact with each other and are not independent; any one of the secondary windings TX-SR11 to TX-SR1n is connected to the secondary winding in module 1.
  • the windings TX-SL11 to TX-SL1n, and the secondary windings in modules 2 and 3 are independent, and the same is true for other magnetic columns, and will not be repeated here.
  • the secondary windings TX-SR11 and TX-SL11 in module 1 and the secondary windings TX-SR21 and TX-SL21 in module 2 share the low-voltage rectifier unit 11; the secondary winding TX in module 1 -SR12, TX-SL12, and the secondary windings TX-SR22 and TX-SL22 in module 2 share the low-voltage rectifier unit 12; and so on, the secondary windings TX-SR1n, TX-SL1n in module 1, and The secondary windings TX-SR2n and TX-SL2n in module 2 share the low-voltage rectifier unit 1n; and so on, the secondary windings TX-SRx1 and TX-SLx1 in module x and the secondary winding in module m TX-SRm1 and TX-SLm1 share the low-voltage rectifier unit (0.5m) 1; the secondary windings TX-SRx2 and TX-SLx2 in module x and the secondary windings TX-
  • Fig. 6 shows an example in which four independent secondary windings share the same low-voltage rectifier unit; at this time, the number of independent secondary windings sharing the same low-voltage rectifier unit can be 4a, a It is a positive integer, such as 4a is 4, 8, etc., the specific value of a is not specifically limited here, it can be determined according to the actual situation, and it is all within the protection scope of this application; The number of independent secondary windings may also be other values, which will not be repeated here, but are all within the protection scope of the present application.
  • each multi-winding transformer the secondary winding of each multi-winding transformer is connected to the corresponding low-voltage rectifier unit to ensure the coupling consistency of the high-voltage conversion unit.
  • a plurality of independent secondary windings can be connected in series to the input end of a common low-voltage rectifier unit (as shown in Figure 7a, Figure 7a uses two independent secondary windings to share a low-voltage rectifier unit, and is based on Figure 4). For example, to demonstrate).
  • a common low-voltage rectifier unit as shown in Figure 7a, Figure 7a uses two independent secondary windings to share a low-voltage rectifier unit, and is based on Figure 4).
  • one end of the TX-S11 of the secondary winding is connected to the head end of the input end of the low-voltage rectifier unit A/D-S11, and the other end of the TX-S11 of the secondary winding is connected to the TX of the secondary winding.
  • One end of -S21 is connected; the other end of the TX-S21 of the secondary winding is connected to the tail end of the input end of the low-voltage rectifier unit A/D-S11.
  • multiple independent secondary windings can also be connected in parallel to the input end of a common low-voltage rectifier unit (as shown in Figure 7b, two independent secondary windings share a low-voltage rectifier unit in Figure 7b, and in Figure 4 On the basis of the example, to demonstrate).
  • a common low-voltage rectifier unit as shown in Figure 7b, two independent secondary windings share a low-voltage rectifier unit in Figure 7b, and in Figure 4 On the basis of the example, to demonstrate).
  • one end of the TX-S11 of the secondary winding is connected to one end of the TX-S21 of the secondary winding, and the connection point is connected to the first end of the input end of the low-voltage rectifier unit A/D-S11.
  • the other end of the TX-S11 of the winding is connected to the other end of the TX-S21 of the secondary winding, and the connection point is connected to the tail end of the input end of the low-voltage rectifier unit A/D-S11.
  • multiple independent secondary windings share the same low-voltage rectifier unit, thereby reducing the total number of low-voltage rectifier units, thereby improving the complexity and cost of the cascaded multi-port converter, and making the cascaded multi-port converter higher power density, lower cost and higher efficiency.
  • the high-voltage conversion unit includes: a DC/AC converter (such as each D/A in FIG. 3-FIG. 6) and a first AC/DC converter (as shown in FIG. 3-FIG. 6 ) of each A/D).
  • a DC/AC converter such as each D/A in FIG. 3-FIG. 6
  • a first AC/DC converter as shown in FIG. 3-FIG. 6
  • the AC side of the first AC/DC converter is used as the input end of the high-voltage conversion unit; the DC side of the first AC/DC converter is connected with the DC side of the DC/AC converter; the AC side of the DC/AC converter is used as the high-voltage converter output of the unit.
  • the first AC/DC converter is a full-bridge structure, as shown in FIG. 9a; or, the first AC/DC converter is a half-bridge structure, as shown in FIG. 9b; no details are given here.
  • the limitations can be determined according to the actual situation, and all fall within the protection scope of the present application.
  • the second AC/DC converter can be removed, and each DC/AC converter can be directly connected in series, and the second AC/DC converter can be cascaded in this case. It can be degenerated into two connecting lines as shown in Figure 9c.
  • the above-mentioned low-voltage rectifier unit includes: a second AC/DC converter; the AC side of the second AC/DC converter is used as the input end of the low-voltage rectifier unit; the DC side of the second AC/DC converter is used as the output end of the low-voltage rectifier unit .
  • the structure formed by the DC/AC converter through the corresponding windings and the second AC/DC converter may be a dual active bridge structure as shown in FIG. 10a , or an LLC structure as shown in FIG. 10b . It can also be the CLLC structure as shown in Figure 10c; of course, it can also be other structures, which will not be repeated here; the structure formed by the DC/AC converter through the corresponding winding and the second AC/DC converter is This is not specifically limited, it may be determined according to the actual situation, and all are within the protection scope of the present application.
  • the cascaded multi-port converter further includes: a plurality of multi-port multiplexing units (multi-port multiplexing unit 1 shown in FIG. 3-FIG. Multiplexing unit 2...multi-port multiplexing unit n).
  • Each input end of the multi-port multiplexing unit is respectively connected with the corresponding output end of different low-voltage rectifying units.
  • the first input terminal of the multi-port multiplexing unit 1 is connected to the output terminal Vout11 of the low-voltage rectifier unit A/D-S11; the second input terminal of the multi-port multiplexing unit 1 It is connected to the output end Vout21 of the low voltage rectifier unit A/D-S21, and so on, the mth input end of the multi-port multiplexing unit 1 is connected to the output end Voutm1 of the low voltage rectifier unit A/D-Sm1.
  • the multi-port multiplexing unit 2 to the multi-port multiplexing unit n, which will not be repeated here, but are all within the protection scope of the present application.
  • each multi-winding transformer is connected to a common bus of at least one group of secondary windings through the corresponding multi-port multiplexing unit.
  • each secondary winding in each multi-winding transformer may be connected to the corresponding secondary windings in other multi-winding transformers through the corresponding low-voltage rectifier unit and the common bus to realize indirect common bus connection.
  • Figures 3 to 6 are shown by taking the example that all secondary windings of each multi-winding transformer have indirect common bus connection.
  • the structure of each multi-winding transformer only part of the secondary windings has common bus connection is the same as that shown in Figure 3 to Figure 6. The structures are similar and will not be repeated here, but are all within the protection scope of the present application.
  • the multi-port multiplexing unit includes: a multi-input coupling branch, or a multi-input coupling branch and a converter at a subsequent stage.
  • the multi-input coupling branch is at least one of the following: a multi-input series structure, a multi-input parallel structure, and a multi-input series-parallel switching structure.
  • FIG. 11a uses 2 inputs as an example. The same is true for other numbers of inputs.
  • the multi-input parallel structure is shown in FIG. 11b .
  • FIG. 11b takes 2 inputs as an example. The same is true for other numbers of inputs, which are not repeated here, and are all within the scope of the present application.
  • the multi-input series-parallel switching structure is shown in Figure 11c, a switch is arranged between the input end and the output end, and a switch is also arranged between the two input ends.
  • the positive pole of the input terminal SHn is connected to the positive pole of the output terminal SOUTn
  • the negative pole of the input terminal SHn is connected to the negative pole of the output terminal SOUTn through the first switch
  • the negative pole of the input terminal SHn is also connected to the positive pole of the input terminal SLn through the second switch.
  • the positive pole of the input terminal SLn is also connected to the positive pole of the output terminal SOUTn through the third switch; the negative pole of the input terminal SLn is connected to the negative pole of the output terminal SOUTn.
  • FIG. 11c shows two inputs as an example. Specifically, the same is true for other numbers of inputs, which will not be repeated here, and are all within the protection scope of the present application.
  • the multi-port multiplexing unit includes a multi-input coupling branch and its subsequent converter
  • the multi-input coupling branch includes a multi-input series-parallel switching structure: if the converter is a bidirectional converter, the multi-input
  • the switches in the series-parallel switching structure are all bidirectional switches, that is, switches that can flow current in both directions; if the converter is a unidirectional converter, the switches in the multi-input series-parallel switching structure can be bidirectional switches, or diodes can be used. Instead of some bidirectional switches, for example, instead of a switch connected to the positive pole of each input terminal, or instead of a switch connected to the negative pole of each input terminal.
  • the converter of the latter stage includes: an inductor and a capacitor; both ends of the capacitor are connected to the positive and negative electrodes of the output terminals of the multi-port multiplexing unit.
  • the positive pole of the input terminal SHn is connected to the negative pole of the input terminal SHn through the first switch and the second switch in turn; one end of the inductor is connected to the connection point between the first switch and the second switch; the other end of the inductor are respectively connected with one end of the capacitor and the positive pole of the output terminal SOUTn; the negative pole of the input terminal SHn is also connected with the connection point between the third switch and the fourth switch; the positive pole of the input terminal SLn is connected to the input through the third switch and the fourth switch in turn The negative pole of the terminal SLn is connected; the negative pole of the input terminal SLn is also connected to the other end of the capacitor and the negative pole of the output terminal SOUTn.
  • the converter of the rear stage of the multi-input coupling branch as a transformer, can realize the gain adjustment itself, so the multi-port multiplexing unit adopts the structure shown in 10d to further reduce the gain range requirement of the front-stage converter, and at the same time, it can achieve Voltage is continuously regulated.
  • the multi-port multiplexing unit When the multi-port multiplexing unit is one-way conversion, its structure can also be the structure shown in FIG. 11e, and the first switch and the fourth switch are replaced by diodes. The specific connection relationship will not be repeated here. , are all within the protection scope of the present application; it can also be the structure shown in Figure 11f, the second switch and the third switch are replaced by diodes, and their specific connection relationships are not repeated here, they are all in this application. within the scope of protection. Replacing two switches with two diodes reduces cost.
  • FIGS. 11 a to 11 f can be used for combination and combination, so as to obtain more flexible and various solutions.
  • Figure 12a to Figure 12c there are several structures with 6 inputs and 1 output; the structure shown in Figure 12a is: first use the structure shown in Figure 11b to connect the three modules in parallel, and then use the paralleled units as follows: The structure shown in Figure 11d is cascaded; the structure shown in Figure 12b is: first use the structure shown in Figure 11b to connect the three modules in parallel, and then use the structure shown in Figure 11c to connect the paralleled units in series.
  • the structure is: first use the structure shown in Figure 11b to connect each two module units in parallel, and then use the structure shown in Figure 11d to adopt a three-stage cascade output scheme; other combinations are in This will not be repeated one by one, and they are all within the protection scope of the present application.
  • the number of inputs is also not specifically limited, and it can be determined according to the actual situation, which are all within the protection scope of this application.
  • each group of low-voltage rectifier units is directly coupled by the corresponding high-voltage conversion unit, but the energy balance of each high-voltage conversion unit cannot be guaranteed; therefore, in practical applications, in each module unit Under the condition that at least one low-voltage rectifier unit and the low-voltage rectifier units corresponding to other module units maintain a common bus connection at the output end, there is at least one of the secondary windings in each multi-winding transformer, and through the corresponding low-voltage rectifier unit and the common busbar, which are indirectly connected with the corresponding secondary windings in other multi-winding transformers; thus, the energy balance of each high-voltage conversion unit and low-voltage rectifier unit can be realized by utilizing the characteristics of the common busbar.
  • Figure 8a is a schematic diagram of part of the common bus and another part of the independent output.
  • Vout11, Vout21...Voutm1 is connected to a common bus
  • Vout12, Vout22... Connection,..., Vout1i, Vout2i...Voutmi are connected to the common busbar; the remaining secondary windings are independently output through the corresponding low-voltage rectifier units, such as Vout1(i+1), Vout2(i+1)...Voutm(i+ 1) Independent output, Vout1(i+2), Vout2(i+2)...Voutm(i+2) independent output,..., Vout1n, Vout2n...Voutm n independent output.
  • all the busbars are shared (not shown in the figure), which will not be repeated here, but are all within the protection scope of the present application.
  • each module unit has 4 secondary windings and each secondary winding is allocated with an independent low-voltage rectifier unit.
  • Each module unit corresponds to the output ends of the 4 low-voltage rectifier units.
  • the case of another part of independent output only 3 output terminals are respectively connected to the corresponding input terminals of the three multi-port multiplexing units, and the remaining output terminals of each module unit are respectively connected to the output terminals of the corresponding multi-port multiplexing unit.
  • At least one group of secondary windings are connected to a common busbar, and at least one group of secondary windings is independently output; all busbars are common: 4 output terminals are respectively connected with the corresponding input terminals of the four multi-port multiplexing units, and other low-voltage
  • the output end of the rectifier unit is also the corresponding input end of the four multi-port multiplexing units, that is, the output end of the 4 low-voltage rectifier units of each module unit and the output ends of the 4 low-voltage rectifier units of other module units.
  • the output terminals correspond to the common bus connection respectively.
  • FIG. 8b For the convenience of description, a special case shown in FIG. 8b is used to illustrate how to achieve energy balance.
  • One secondary winding in module 2 is connected to the AC side of the low-voltage rectifier unit A/D-S21; the other secondary winding in module 2 is connected to the AC side of the low-voltage rectifier unit A/D-S22; the low-voltage rectifier unit
  • the DC side of the A/D-S21 is used as its own output terminal Vout21; the DC side of the low-voltage rectifier unit A/D-S22 is used as its own output terminal Vout22.
  • One secondary winding in module 3 is connected to the AC side of the low-voltage rectifier unit A/D-S31; the other secondary winding in module 3 is connected to the AC side of the low-voltage rectifier unit A/D-S32; the low-voltage rectifier unit
  • the DC side of the A/D-S31 is used as its own output terminal Vout31; the DC side of the low-voltage rectifier unit A/D-S32 is used as its own output terminal Vout32.
  • the output terminal Vout11 of the low-voltage rectifier unit A/D-S11, the output terminal Vout21 of the low-voltage rectifier unit A/D-S21, and the output terminal Vout31 of the low-voltage rectifier unit A/D-S31 are connected to a common bus, that is, in different multi-winding transformers
  • the corresponding secondary windings are connected to the indirect common bus through the corresponding low-voltage rectifier unit;
  • the output terminal Vout32 of /D-S32 is output independently.
  • the arrow line in FIG. 8b represents the energy flow when only the output terminal Vout12 of the low-voltage rectifier unit A/D-S12 has output energy demand.
  • the high-voltage conversion units of modules 2 and 3 respectively provide 1/3 of the total output energy to the common bus through their low-voltage rectifier units, and then transmit 2/3 of the energy to the low-voltage rectifier unit A/
  • the output terminal Vout12 of D-S12, the high voltage conversion unit of module 1 directly provides another 1/3 energy to the output terminal Vout12 of the low voltage rectifier unit A/D-S12, so as to ensure the energy balance of the high voltage conversion unit.
  • each secondary winding connected to a common bus can also be connected to an external power source through a common bus.
  • the output terminal Vout11 of the low-voltage rectifier unit A/D-S11, the output terminal Vout21 of the low-voltage rectifier unit A/D-S21, and the output terminal Vout31 of the low-voltage rectifier unit A/D-S31 pass through the common bus. Connect to the DC power supply.
  • Figure 8c provides a low-voltage bus, ie a common bus.
  • the high-voltage conversion units provide the same energy respectively, and the common bus on the low-voltage side provides additional energy balance.
  • Figure 8d a more extreme situation is provided.
  • the high-voltage conversion unit does not provide energy, and the energy of the independent output is completely provided by the additional energy input on the low-voltage side.
  • Figures 8a-8c are all the connection relationships of some common busbars.
  • the connection relationships and working principles of all the common busbars are similar to the descriptions corresponding to Figures 8a-8c, and they will not be repeated here. , all within the scope of protection of this application.
  • the low-voltage rectifier unit is bidirectional.
  • the AC side is recorded as the input end, and the DC side is recorded as the output end.
  • the energy coordination of multiple groups of low-voltage rectifier units is realized by using the common bus, so as to ensure the energy balance of the high-voltage conversion units, while reducing the complexity of the system and the number of low-voltage rectifier units;
  • the common low-voltage bus provided for the system can be Other energy sources are connected and provided conveniently, which is convenient to realize such as optical storage and charging coupling, and improve the reusability of the system; in the case of ensuring that at least one group of low-voltage rectifier units share the same bus, the connection between other groups of low-voltage rectifier units and some of the low-voltage rectifier units Independent, so that the energy balance of each high-voltage conversion unit and low-voltage rectifier unit can be realized by using the characteristics of the common bus.
  • the module m+ 1 It depends on its specific application environment, and it is all within the protection scope of this application.
  • each multi-winding transformer provides secondary windings for the corresponding multiple low-voltage side outputs; and for each low-voltage rectified voltage connected to a common bus, its The corresponding total output of the low-voltage side is summarized from the output of the corresponding high-voltage conversion units through the multi-port multiplexing unit; from the high-voltage side, each high-voltage conversion unit is connected to the primary winding of the corresponding multi-winding transformer; thus ensuring multiple The energy of the low-voltage side output (Vout1-Vouti shown in Figure 3- Figure 6) comes from the corresponding multiple high-voltage conversion units, and the multiple secondary windings themselves can be easily insulated to meet the insulation requirements; At the same time, multiple low-voltage sides can implement independent control of the total output voltage through a low-voltage rectifier unit, or a low-voltage rectifier unit and a multi-port multiplexing unit.
  • An embodiment of the present invention provides a three-phase medium-voltage input system, as shown in FIG. 13 , including: three phase units, and the phase units include: an inductor and the cascaded multi-port converter provided in any of the above embodiments; wherein:
  • each phase unit is directly connected with the medium voltage grid; the tail end of the input end of each phase unit is connected.
  • Each phase unit is connected in the same way, so that the low-voltage side output energy of each phase unit is directly coupled with all units in the three-phase cascade system.
  • the head end of the input end of the cascaded multi-port converter is connected to one end of the inductor; the other end of the inductance is used as the head end of the input end of the phase unit; the tail end of the input end of the cascaded multi-port converter is used as the phase unit the input end of the .
  • the low-voltage rectifier unit when a cascaded multi-port low-voltage rectifier unit in each phase unit is connected to multiple independent secondary windings, the low-voltage rectifier unit can be connected to independent secondary windings in different phase units, or it can be The independent secondary windings in the same phase unit are connected.
  • the first low-voltage rectifier unit is connected to one secondary winding of the first phase unit and one secondary winding of the second phase unit respectively, and these two The secondary windings are independent; they will not be repeated here, as long as each secondary winding connected to the same low-voltage rectifier unit is independent, it is not limited whether these secondary windings originate from the same phase unit, nor do they come from In the same multi-winding transformer, the specific connection relationship of each low-voltage rectifier unit can be determined according to the actual situation, and it is all within the protection scope of the present application.
  • cascaded multiport converters may share the same group of multiport multiplexing units; each cascaded multiport converter may also have its own set of multiport multiplexing units.
  • the structures of the cascaded multi-port converters may be the same or different; the structure shown in FIG. 13 is only an example. the above embodiment.
  • cascaded multi-port converter For the specific structure and working principle of the cascaded multi-port converter, refer to the above-mentioned embodiments for details, which are not repeated here, but are all within the protection scope of the present application. It should be noted that the cascaded multi-port converter can also be applied to other systems, which will not be repeated here, but are all within the protection scope of the present application.
  • multiple independent secondary windings share the same low-voltage rectifier unit, thereby reducing the total number of low-voltage rectifier units, thereby improving the complexity and cost of the three-phase medium-voltage input system, and making the three-phase medium-voltage input system more efficient High power density, lower cost, higher efficiency.
  • An embodiment of the present invention provides a three-phase medium voltage input system, as shown in FIG. 14 , including: an MMC converter and N DC conversion units, where the DC conversion unit includes: an inductor and the cascaded type provided by any of the above embodiments. Multiport converter; N is a positive integer.
  • the head end of the input end of each DC conversion unit is connected to the positive electrode of the DC side of the MMC converter; the tail end of the input end of each DC conversion unit is connected to the negative electrode of the DC side of the MMC converter.
  • the AC side of the MMC converter is connected to the medium voltage grid.
  • the first end of the input end of the cascaded multi-port converter is connected to one end of the inductor; the other end of the inductor is used as the input end of the DC conversion unit; the input end of the cascaded multi-port converter is used as the end.
  • the tail end of the input end of the DC conversion unit is used as the end.
  • each DC conversion unit is connected to the medium-voltage grid through the MMC converter; that is, the high-voltage side first uses the MMC converter to construct the high-voltage DC bus, and then cascades the high-voltage DC bus to connect with at least two
  • the ports are mutually isolated low-voltage DC power sources for energy exchange, and multiple ports realize direct energy coupling.
  • the first AC/DC converter of the cascaded multi-port converter in the DC conversion unit is replaced by two through leads.
  • the low-voltage rectifier unit can be connected to independent secondary windings in different DC conversion units, and also It can be connected to independent secondary windings in the same DC conversion unit.
  • the first low-voltage rectifier unit is connected to one of the secondary windings of the first DC conversion unit and one of the secondary windings of the second DC conversion unit.
  • the two secondary windings are independent; I will not repeat them one by one here, as long as each secondary winding connected to the same low-voltage rectifier unit is independent, it is not limited whether these secondary windings originate from the same DC conversion unit. It does not limit whether it is from the same multi-winding transformer.
  • the specific connection relationship of each low-voltage rectifier unit can be determined according to the actual situation, which is all within the protection scope of this application.
  • cascaded multiport converters may share the same group of multiport multiplexing units; each cascaded multiport converter may also have its own set of multiport multiplexing units.
  • the structures of the cascaded multi-port converters may be the same or different; the structure shown in FIG. 14 is only an example. the above embodiment.
  • cascaded multi-port converter For the specific structure and working principle of the cascaded multi-port converter, refer to the above-mentioned embodiments for details, which are not repeated here, but are all within the protection scope of the present application. It should be noted that the cascaded multi-port converter can also be applied to other systems, which will not be repeated here, but are all within the protection scope of the present application.
  • multiple independent secondary windings share the same low-voltage rectifier unit, thereby reducing the total number of low-voltage rectifier units, thereby improving the complexity and cost of the N-phase medium-voltage input system, and making the three-phase medium-voltage input system more efficient High power density, lower cost, higher efficiency.

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Abstract

本申请提供一种级联式多端口变换器及三相中压输入系统，各个模组单元的输入端级联，级联后的两端作为级联式多端口变换器的输入端两端口；模组单元中：各个高压变换单元的输入端级联，级联后的两端作为模组单元的输入端两端口；各个高压变换单元的输出端分别与各个多绕组变压器中相应的原边绕组相连；各个多绕组变压器中各个副边绕组分别作为模组单元的输出端、与相应的低压整流单元的输入端相连；并且多绕组变压器中的磁芯上绕制有多个原边绕组和多个副边绕组，因此，多个高压变换单元的绕组共用磁芯，可以减少级联式多端口变换器中多绕组变压器的数量，相应减少低压整流单元的数量；从而减少级联式多端口变换器的体积、重量及成本。

Description

一种级联式多端口变换器及三相中压输入系统
本申请要求于2020年09月30日提交中国专利局、申请号为202011059741.9、发明名称为“一种级联式多端口变换器及三相中压输入系统”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。
技术领域
本申请涉及电力电子技术领域，更具体的说，尤其涉及一种级联式多端口变换器及三相中压输入系统。
背景技术
传统直流充电桩一般先通过工频降压变压器将中压降至市电电压，如中国为380V，再经电源模块将市电电压变换为可供电动车使用的直流电压，如200－1000Vdc，为电动车充电；如图1所示，工频电压器原边绕组与一次侧高压电源相连，工频变压器的副边绕组分别与各个直流充电桩模块的交流侧相连，每个直流充电桩模块的直流侧(如图1所示的Vout1、Vout2……Voutn)连接电源模块的充电口。由于安规的需求，在允许多辆汽车同时充电地场合，电源模块的输入、输出之间需要隔离，因此，不仅各个直流充电桩模块前级需要设置有该工频变压器，而且该直流充电桩模块中还需要在AC/DC变换器(如图1所示的A/D)后级设置有隔离DC/DC变换器(如图1所示的隔离D/D)；从而导致该方案存在夜间自损耗、体积大等缺陷。
因此，有方案提出使用级联式电力电子变压器方案，如图2所示，每个模组(如图2所示的模组1、模组2……模组m)中包括：第一AC/DC变换器(如图2所示的A/D-P1、A/D-P1……A/D-Pm)、DC/AC变换器(如图2所示的D/A-P1、D/A-P1……D/A-Pm)、变压器和第二AC/DC变换器(如图2所示的A/D-S12、A/D-S22……A/D-Sm2)；各个模组的输出端并联成直流母线，再通过各个隔离DC/DC变换器(如图2所示的隔离DC/DC1、隔离DC/DC2……隔离DC/DCn)与电源模块的充电口相连；由于各充电口之间需要存在隔离以保证充电安全，为满足输入电压要求，需要较多数量模组进行级联，从而使得每一级联模块(即第一AC/DC变换器)的输出电压为相应安全电压；而本方案中，级联模块的数量较多，增加了变换器的体积、重量及成本。
发明内容
有鉴于此，本申请实施例提供一种级联式多端口变换器及三相中压输入系统，用于减少级联模块的数量，进而减少级联式多端口变换器的体积、重量及成本。
本发明第一方面公开了一种级联式多端口变换器，包括：多个模组单元和多个低压整流单元，所述模组单元包括：至少一个多绕组变压器和多个高压变换单元；
各个所述模组单元的输入端级联，级联后的两端作为所述级联式多端口变换器的输入端两端口；
所述模组单元中：各个所述高压变换单元的输入端级联，级联后的两端作为所述模组单元的输入端两端口；所述多绕组变压器中的磁芯上绕制有多个原边绕组和至少一个副边绕组；各个所述高压变换单元的输出端分别与相应的所述原边绕组相连；所述副边绕组与相应的所述低压整流单元的对应输入端相连。
可选的，所述低压整流单元的个数等于全部所述副边绕组的总个数，各个所述副边绕组与各个所述低压整流单元的输入端一一对应连接。
可选的，所述低压整流单元的个数小于全部所述副边绕组的总个数，多个独立的所述副边绕组共用同一个所述低压整流单元。
可选的，多个独立的所述副边绕组，包括：不同所述多绕组变压器的副边绕组；和/或，同一所述多绕组变压器中不同磁柱上的副边绕组。
可选的，多个独立的所述副边绕组，串联连接于共用的所述低压整流单元的输入端，或者，并联连接于共用的所述低压整流单元的输入端。
可选的，相应的所述低压整流单元的输出端之间共母线连接，以使至少一个所述多绕组变压器中，均存在至少一个所述副边绕组，分别与其他至少一个所述多绕组变压器中相应所述副边绕组存在间接连接关系。
可选的，各个所述多绕组变压器中，均存在至少一个所述副边绕组，通过相应的所述低压整流单元及公共母线，分别与其他各个所述多绕组变压器中相应所述副边绕组存在间接连接关系。
可选的，共母线相连的各个所述副边绕组，还通过公共母线与外部电源相连。
可选的，共母线相连的低压整流单元所连接的各个多绕组变压器中，各个所述模组单元，其内部的副边绕组均用于与其他对应副边绕组实现间接共母线连接。
可选的，还包括：至少一个额外的冗余模组单元；
所述冗余模组单元内的各个副边绕组均通过相应的低压整流单元独立输出。
可选的，还包括：多个多端口复用单元；
所述多端口复用单元的各个输入端分别与不同低压整流单元的相应输出端相连。
可选的，所述多端口复用单元包括：多输入耦合支路，或者，多输入耦合支路及其后级的变换器。
可选的，所述多输入耦合支路为以下至少一种：多输入串联结构、多输入并联结构及多输入串并联切换结构。
可选的，所述多端口复用单元包括多输入耦合支路及其后级的变换器，且所述多输入耦合支路包括所述多输入串并联切换结构时：
所述多输入串并联切换结构中的开关均为双向开关。
可选的，若所述变换器为单向变换器，则所述多输入串并联切换结构中连接输入端正极或负极的双向开关由二极管替代。
可选的，所述高压变换单元，包括：DC/AC变换器和第一AC/DC变换器；
所述第一AC/DC变换器的交流侧作为所述高压变换单元的输入端；
所述第一AC/DC变换器的直流侧与所述DC/AC变换器的直流侧相连；
所述DC/AC变换器的交流侧作为所述高压变换单元的输出端。
可选的，所述第一AC/DC变换器为全桥式结构或半桥式结构。
可选的，所述低压整流单元，包括：第二AC/DC变换器；
所述第二AC/DC变换器的交流侧作为所述低压整流单元的输入端；
所述第二AC/DC变换器的直流侧作为所述低压整流单元的输出端。
可选的，所述DC/AC变换器通过相应绕组与所述第二AC/DC变换器所构成的结构是：双有源桥结构、LLC结构及CLLC结构中的任意一种。
本发明第二方面公开了一种三相中压输入系统，包括：三个相单元，所述 相单元包括：电感和本发明第一方面一所述的级联式多端口变换器；其中：
各个所述相单元的输入端首端与中压电网相连；
各个所述相单元的输入端尾端相连；
所述相单元中，所述级联式多端口变换器的输入端首端与所述电感的一端相连；所述电感的另一端作为所述相单元的输入端首端；所述级联式多端口变换器的输入端尾端作为所述相单元的输入端尾端。
本发明第三方面公开了一种三相中压输入系统，包括：MMC变换器和N个直流变换单元，所述直流变换单元包括：电感和本发明第一方面任一所述的级联式多端口变换器；N为正整数；
各个所述直流变换单元的输入端首端与所述MMC变换器的直流侧正极相连；
各个所述直流变换单元的输入端尾端与所述MMC变换器的直流侧负极相连；
所述MMC变换器的交流侧与中压电网相连；
所述直流变换单元中，所述级联式多端口变换器的输入端首端与所述电感的一端相连；所述电感的另一端作为所述直流变换单元的输入端首端；所述级联式多端口变换器的输入端尾端作为所述直流变换单元的输入端尾端；
所述直流变换单元中所述级联式多端口变换器的第一AC/DC变换器由两根直通引线代替。
从上述技术方案可知，本发明提供的一种级联式多端口变换器，各个模组单元的输入端级联，级联后的两端作为级联式多端口变换器的输入端两端口；模组单元中：各个高压变换单元的输入端级联，级联后的两端作为模组单元的输入端两端口；各个高压变换单元的输出端分别与各个多绕组变压器中相应的原边绕组相连；各个多绕组变压器中各个副边绕组分别作为模组单元的输出端、与相应的低压整流单元的输入端相连；并且多绕组变压器中的磁芯上绕制有多个原边绕组和多个副边绕组，因此，多个高压变换单元的绕组共用磁芯，可以减少级联式多端口变换器中多绕组变压器的数量，也相应减少低压整流单元的数量；从而减少级联式多端口变换器的体积、重量及成本。
附图说明
为了更清楚地说明本申请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申请的一些实施例，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示出的结构获得其他的附图。
图1是现有技术实施例提供的一种电源模块的示意图；
图2是现有技术实施例提供的另一种电源模块的示意图；
图3是本发明实施例提供的一种级联式多端口变换器的示意图；
图4是本发明实施例提供的另一种级联式多端口变换器的示意图；
图5是本发明实施例提供的另一种级联式多端口变换器的示意图；
图6是本发明实施例提供的另一种级联式多端口变换器的示意图；
图7a和图7b为两个独立的副边绕组与低压整流单元连接的示意图；
图8a至图8d是本发明实施例提供的另一种级联式多端口变换器的示意图；
图9a至图9c是本发明实施例提供的另一种级联式多端口变换器中第一AC/DC变换器的示意图；
图10a至图10c是本发明实施例提供的一种级联式多端口变换器中第二AC/DC变换器、DC/AC变换器的结构示意图；
图11a至图11f是本发明实施例提供的一种级联式多端口变换器中一种多端口复用单元的示意图；
图12a至图12c是本发明实施例提供的一种级联式多端口变换器中另一种多端口复用单元的示意图；
图13是本发明实施例提供的一种三相中压输入系统的示意图；
图14是本发明实施例提供的另一种三相中压输入系统的示意图；
图15是本发明实施例提供的另一种级联式多端口变换器的示意图。
具体实施方式
为使本发明实施例的目的、技术方案和优点更加清楚，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。
在本申请中，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、物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、物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，并不排除在包括所述要素的过程、方法、物品或者设备中还存在另外的相同要素。
本发明实施例提供一种级联式多端口变换器，用于解决现有技术中级联模块的数量较多，增加了变换器的体积、重量及成本的问题。
参见图3，该级联式多端口变换器，包括：多个模组单元(如图3所示的模组1-模组m)和多个低压整流单元(如图3所示的A/D-S11至A/D-S1n，A/D-S21至A/D-S2n，以及A/D-Sm1至A/D-Smn)，模组单元包括：至少一个多绕组变压器和多个高压变换单元(以模组1中的第1个高压变换单元为例，包括如图3所示的A/D-P11与D/A-P11)。
各个模组单元的输入端级联，级联后的两端作为级联式多端口变换器的输入端两端口，具体的，如图3所示，模组1的输入端首端作为级联式多端口变换器的输入端首端、与一次侧高压电源的一端相连，模组1的输入端尾端与模组2的输入端首端相连，模组2的输入端尾端与模组3的输入端首端相连；以此类推，模组m-1的输入端尾端与模组m的输入端首端相连，模组m的输入端尾端作为级联式多端口变换器的输入端尾端、与一次侧高压电源的另一端相连。
需要说明的是，模组单元的数量m在此不做具体限定，视实际情况而定即可，均在本申请的保护范围内。
模组单元中：各个高压变换单元的输入端级联，级联后的两端作为模组单元的输入端两端口；多绕组变压器中的磁芯上绕制有多个原边绕组和至少一个副边绕组；各个高压变换单元的输出端分别与相应的多绕组变压器中相应原边绕组相连；副边绕组与相应的低压整流单元的对应输入端相连。
也就是说，一个多绕组变压器的原边侧可以与多个高压变换单元相连；一个多绕组变压器的副边侧也可以与一个低压整流单元相连，或者，一个多绕组变压器的副边侧与多个低压整流单元相连(如图3所示)；进而控制级联式多端口变换器中高压变换单元两端的电压小于相应阈值。
以图3所示的模组1为例进行说明，其中，图3中模组1包括：i个高压变换单元，A/D-P1b与D/A-P1b构成第b个高压变换单元，其中0<b≤i。
具体的，第1个高压变换单元的输入端首端作为模组1的输入端首端，第1个高压变换单元的输入端尾端与第2个高压变换单元的输入端首端相连；第2个高压变换单元的输入端尾端与第3个高压变换单元的输入端首端相连；以此类推，第i-1个高压变换单元的输入端尾端与第i个高压变换单元的输入端首端相连；第i个高压变换单元的输入端尾端作为模组1的输入端尾端。
本实施例中，如图3所示，高压变换单元的总个数为i+j+…+k；现有技术中高压侧各级联单元的总个数为s，各个高压侧各级联单元分压，因此，现在技术中低压侧A/D单元的总个数远远比本实施例中的低压整流单元的总个数要多很多，且还需要较多的变压器；因此，本实施例通过多绕组变压器中的磁芯上绕制有多个原边绕组和多个副边绕组，多个高压变换单元的对应的原边绕组共用磁芯，利用磁路耦合使得每一组低压整流单元均与高压变换单元耦合，并将多个高压变换单元的能量与多个低压整流单元能量实现交互，可以减少级联式多端口变换器中多绕组变压器的数量，也相应减少低压整流单元的数量；从而减少级联式多端口变换器的体积、重量及成本。
在上述实施例中，低压整流单元的个数与全部副边绕组的总个数可以相等，也可以不相等；在此，分别对低压整流单元的个数等于全部副边绕组的总个数，以及，低压整流单元的个数小于全部副边绕组的总个数这两种情况进行说明：
(1)低压整流单元的个数等于全部副边绕组的总个数，各个副边绕组与各个低压整流单元的输入端一一对应连接。
也就是说，各个低压整流单元的输入端均仅与一个副边绕组的相连，即副边绕组和低压整流单元为一对一的关系。
具体的，如图3所示，以模组1为例进行说明，低压整流单元A/D-S11的输入端与模组1中第1个副边绕组相连；低压整流单元A/D-S12的输入端与模组1中第2个副边绕组相连，以此类推，低压整流单元A/D-S1n的输入端与模组1中第n个副边绕组相连；需要说明的是，各个低压整流单元的直交流侧作为自身的输入端，直流侧作为自身的输出端(如图3所示的Vout11-Vout1n，Vout21-Vout2n，以及Voutm1-Voutmn)。
值得说明的是，如果同一磁柱上绕制过多的原边绕组，会使得多个原边绕组之间压差过大，进而增加绝缘设计难度；而如果绕制过少的原边绕组，则又会使得低压整流单元的数量过多；针对于此提出多个独立的副边绕组通过串并方式共用一个低压整流单元，从而在改善多个原边绕组间压差过大的同时，解决低压整流单元的数量过多的问题，详情参阅下述说明。
(2)低压整流单元的个数小于全部副边绕组的总个数，多个独立的副边绕组共用同一个低压整流单元。
需要说明的是，任两个副边绕组之间是否独立，可以判断这两个副边绕组之间会不会相互影响，如果相互影响，则不独立，否则独立。一般情况下，处于同一磁柱上的副边绕组之间相互影响；即不同变压器中的副边绕组之间不会相互影响、独立，同一变压器中的不同磁柱上的副边绕组不相互影响、独立。
1、在实际应用中，如图4所示，各个模组单元中均包括一个多绕组变压器，且该多绕组变压器仅包括一个磁柱；不同多绕组变压器的副边绕组之间相互独立，如模组1中的任一副边绕组与模组2和模组3中的副边绕组，均为独立；同一个模组单元内的副边绕组之间不独立；如模组1内的各个副边绕组之间不独立；即多个独立的副边绕组包括：不同多绕组变压器的副边绕组；因此，各个相互独立的副边绕组可以共用一个低压整流单元。
具体的，模组1中的副边绕组TX-S11和模组2中的副边绕组TX-S21共用低压整流单元11；模组1中的副边绕组TX-S12和模组2中的副边绕组TX-S22共用低压整流单元12，以此类推，模组1中的副边绕组TX-S1n和模组2中的副边绕组TX-S2n共用低压整流单元1n；以此类推，模组x中的副边绕组TX-Sx1和模组m中的副边绕组TX-Sm1共用低压整流单元(0.5m)1；模组x中的副边绕组TX-Sx2和模组m中的副边绕组TX-Sm2共用低压整流单 元(0.5m)2，以此类推，模组x中的副边绕组TX-Sxn和模组2中的副边绕组TX-Smn共用低压整流单元(0.5m)n。
需要说明的是，图4以2个独立的副边绕组共用同一个低压整流单元为例进行展示，因此，低压整流单元的个数为0.5m，低压整流单元的个数与共用同一个低压整流单元的独立的副边绕组的个数相关。此时，共用同一个低压整流单元的独立的副边绕组的个数可以为2a，a为正整数，如2a为2、4、6、8等，a的具体取值在此不做具体限定，视实际情况而定即可，均在本申请的保护范围内。当然，共用同一个低压整流单元的独立的副边绕组的个数也可以是其他数值，在此不再一一赘述，均在本申请的保护范围内。
在实际应用中，若级联式多端口变换器所在的系统中，仅包括一个级联式多端口变换器，则该级联式多端口变换器中不同多绕组变压器的副边绕组之间相互独立；若级联式多端口变换器所在的系统中包括至少两个级联式多端口变换器，且各个级联式多端口变换器采用相同的方式连接于该系统中，则不同级联式多端口变换器的副边绕组之间相互独立，其具体结构在此不再一一赘述，视实际情况而定即可，均在本申请的保护范围内。
值得说明的是，同一多绕组变压器的各绕组间均存在较好的耦合；而在高压绝缘需求的场合，同一多绕组变压器中不同磁柱的绕组耦合性会有较大幅度的下降，为了规避因此而带来的功率不平衡问题，将同一多绕组变压器的不同磁柱上的副边绕组当作独立的副边绕组。也即下面的第2种情况：
2、在实际应用中，如图5所示，各个模组单元中均包括一个多绕组变压器，且该多绕组变压器包括至少两个磁柱；同一多绕组变压器中不同磁柱上的副边绕组为独立绕组；如模组1中一个磁柱上的副边绕组TX-SR11至TX-SR1n之间相互影响、不独立；副边绕组TX-SR11至TX-SR1n中的任意一个，与模组1中另一个磁柱上的副边绕组TX-SL11至TX-SL1n，模组2和3中的副边绕组均为独立，其他磁柱上的副边绕组同理，在此不再一一赘述。
具体的，模组1中的副边绕组TX-SR11和模组1中的副边绕组TX-SL11共用低压整流单元11；模组1中的副边绕组TX-SR12和模组1中的副边绕组TX-SL12共用低压整流单元12，以此类推，模组1中的副边绕组TX-SR1n和模组1中的副边绕组TX-SL1n共用低压整流单元1n。模组2中的副边绕组 TX-SR21和模组2中的副边绕组TX-SL21共用低压整流单元21；模组2中的副边绕组TX-SR22和模组2中的副边绕组TX-SL22共用低压整流单元22，以此类推，模组2中的副边绕组TX-SR2n和模组2中的副边绕组TX-SL2n共用低压整流单元2n；以此类推，模组x中的副边绕组TX-SRx1和模组x中的副边绕组TX-SLx1共用低压整流单元x1；模组x中的副边绕组TX-SRx2和模组x中的副边绕组TX-SLx2共用低压整流单元x2，以此类推，模组x中的副边绕组TX-SRxn和模组x中的副边绕组TX-SLxn共用低压整流单元xn。模组m中的副边绕组TX-SRm1和模组m中的副边绕组TX-SLm1共用低压整流单元m1；模组m中的副边绕组TX-SRm2和模组m中的副边绕组TX-SLm2共用低压整流单元m2，以此类推，模组m中的副边绕组TX-SRmn和模组m中的副边绕组TX-SLmn共用低压整流单元mn。
需要说明的是，图5以2个独立的副边绕组共用同一个低压整流单元为例进行展示；此时，共用同一个低压整流单元的独立的副边绕组的个数可以为2a，a为正整数，如2a为2、4、6、8等，a的具体取值在此不做具体限定，视实际情况而定即可，均在本申请的保护范围内；当然，共用同一个低压整流单元的独立的副边绕组的个数也可以是其他数值，在此不再一一赘述，均在本申请的保护范围内。
3、在实际应用中，结合图4和图5，如图6所示，每个模组单元中均有各自的多绕组变压器，且每个多绕组变压器均包括至少两个磁柱，则级联式多端口变换器中包括至少两个分别含有至少两个磁柱的多绕组变压器；同一多绕组变压器中不同磁柱上的副边绕组为独立绕组；不同多绕组变压器的副边绕组为独立绕组；如模组1中的副边绕组TX-SR11至TX-SR1n之间相互影响、不独立；副边绕组TX-SR11至TX-SR1n中的任意一个，与模组1中的副边绕组TX-SL11至TX-SL1n，模组2和3中的副边绕组均为独立，其他磁柱上同理，在此不再一一赘述。
具体的，模组1中的副边绕组TX-SR11、TX-SL11，以及模组2中的副边绕组TX-SR21、TX-SL21共用低压整流单元11；模组1中的副边绕组TX-SR12、TX-SL12，以及模组2中的副边绕组TX-SR22、TX-SL22共用低压整流单元12；以此类推，模组1中的副边绕组TX-SR1n、TX-SL1n，以及模组2中的副 边绕组TX-SR2n、TX-SL2n共用低压整流单元1n；以此类推，模组x中的副边绕组TX-SRx1、TX-SLx1，以及模组m中的副边绕组TX-SRm1、TX-SLm1共用低压整流单元(0.5m)1；模组x中的副边绕组TX-SRx2、TX-SLx2，以及模组m中的副边绕组TX-SRm2、TX-SLm2共用低压整流单元(0.5m)2；以此类推，模组x中的副边绕组TX-SRxn、TX-SLxn，以及模组m中的副边绕组TX-SRmn、TX-SLmn共用低压整流单元(0.5m)n。
需要说明的是，图6以4个独立的副边绕组共用同一个低压整流单元的为例进行展示；此时，共用同一个低压整流单元的独立的副边绕组的个数可以为4a，a为正整数，如4a为4、8等，a的具体取值在此不做具体限定，视实际情况而定即可，均在本申请的保护范围内；当然，共用同一个低压整流单元的独立的副边绕组的个数也可以是其他数值，在此不再一一赘述，均在本申请的保护范围内。
在各个多绕组压器中，每一个多绕组变压器的副边绕组均接入相应的低压整流单元中，以保高压变换单元的耦合一致性。
在上述1、2、3三种情况中，多个独立的副边绕组共用一个低压整流单元时：
多个独立的副边绕组可以是串联连接于共用的低压整流单元的输入端(如图7a所示，图7a以2个独立的副边绕组共用一个低压整流单元，且在图4的基础之上为例，进行展示)。具体的，如图7a所示，副边绕组的TX-S11的一端与低压整流单元A/D-S11的输入端首端相连，副边绕组的TX-S11的另一端与副边绕组的TX-S21的一端相连；副边绕组的TX-S21的另一端与低压整流单元A/D-S11的输入端尾端相连。
或者，多个独立的副边绕组也可以是并联连接于共用的低压整流单元的输入端(如图7b所示，图7b以2个独立的副边绕组共用一个低压整流单元，且在图4的基础之上为例，进行展示)。具体的，如图7b所示，副边绕组的TX-S11的一端与副边绕组的TX-S21的一端相连，连接点与低压整流单元A/D-S11的输入端首端相连，副边绕组的TX-S11的另一端与副边绕组的TX-S21的另一端相连，连接点与低压整流单元A/D-S11的输入端尾端相连。
在本实施例中，多个独立的副边绕组共用同一个低压整流单元，进而减少 低压整流单元的总数量，从而改善级联式多端口变换器复杂度及成本，使得级联式多端口变换器更高功率密度、更低成本、更高效率。
在上述任一实施例中，该高压变换单元，包括：DC/AC变换器(如图3-图6中的各个D/A)和第一AC/DC变换器(如图3-图6中的各个A/D)。
第一AC/DC变换器的交流侧作为高压变换单元的输入端；第一AC/DC变换器的直流侧与DC/AC变换器的直流侧相连；DC/AC变换器的交流侧作为高压变换单元的输出端。
在实际应用中，第一AC/DC变换器为全桥式结构，如图9a所示；或者，第一AC/DC变换器为半桥式结构，如图9b所示；在此不做具体限定，视实际情况而定即可，均在本申请的保护范围内。具体的，在级联式多端口变换器的高压侧为直流输入时，可以去掉该第二AC/DC变换器，直接将各个DC/AC变换器串联，此时级联第二AC/DC变换可以退化为如图9c所示的两根连线。
上述低压整流单元，包括：第二AC/DC变换器；第二AC/DC变换器的交流侧作为低压整流单元的输入端；第二AC/DC变换器的直流侧作为低压整流单元的输出端。
需要说明的是，DC/AC变换器通过相应绕组与第二AC/DC变换器所构成的结构可以是如图10a所示的双有源桥结构；也可以是如图10b所示的LLC结构；还可以是如图10c所示的CLLC结构；当然也可以是其他结构，在此不再一一赘述；DC/AC变换器通过相应绕组与第二AC/DC变换器所构成的结构，在此不做具体限定，视实际情况而定即可，均在本申请的保护范围内。
可选的，在上述任一实施例中，该级联式多端口变换器，还包括：多个多端口复用单元(如图3-图6所示的多端口复用单元1、多端口复用单元2……多端口复用单元n)。
多端口复用单元的各个输入端分别与不同低压整流单元的相应输出端相连。具体的，以图3为例进行说明，多端口复用单元1的第1个输入端与低压整流单元A/D-S11的输出端Vout11相连；多端口复用单元1的第2个输入端与低压整流单元A/D-S21的输出端Vout21相连，以此类推，多端口复用单元 1的第m个输入端与低压整流单元A/D-Sm1的输出端Voutm1相连。多端口复用单元2至多端口复用单元n同理，在此不再一一赘述，均在本申请的保护范围内。
需要说明的是，各个多绕组变压器的副边绕组通过相应的多端口复用单元实现至少一组副边绕组共母线连接。实际应用中，可以是各个多绕组变压器中，各个副边绕组，分别与其他各个多绕组变压器中相应副边绕组，通过相应的低压整流单元及公共母线实现间接共母线相连。图3-图6均以各个多绕组变压器的全部副边绕组均存在间接共母线连接为例进行展示，各个多绕组变压器仅部分副边绕组存在共母线连接的结构与图3-图6所示结构相似，在此不再一一赘述，均在本申请的保护范围内。
在实际应用中，该多端口复用单元包括：多输入耦合支路，或者，多输入耦合支路及其后级的变换器。
该多输入耦合支路为以下至少一种：多输入串联结构、多输入并联结构及多输入串并联切换结构。
需要说明的是，多输入串联结构如图11a所示，图11a以2输入为例进行展示，其他数量的输入同理，在此不再一一赘述，均在本申请的保护范围内。多输入并联结构如图11b所示，图11b以2输入为例进行展示，其他数量的输入同理，在此不再一一赘述，均在本申请的保护范围内。多输入串并联切换结构如图11c所示，输入端与输出端之间设置有开关，两个输入端之间也设置有开关。具体的，输入端SHn的正极与输出端SOUTn的正极相连，输入端SHn的负极通过第一开关与输出端SOUTn的负极相连，输入端SHn的负极还通过第二开关与输入端SLn的正极相连；输入端SLn的正极还通过第三开关与输出端SOUTn的正极相连；输入端SLn的负极与输出端SOUTn的负极相连。图11c以2输入为例进行展示，具体的，其他数量的输入同理，在此不再一一赘述，均在本申请的保护范围内。在输入耦合支路采用如图11c所示的结构时，能够实现接入单元的串并联切换，进而降低前级变流器增益范围要求。
在实际应用中，多端口复用单元包括多输入耦合支路及其后级的变换器，且多输入耦合支路包括多输入串并联切换结构时：若变换器为双向变换器，则多输入串并联切换结构中的开关均为双向开关，即可以双向流通电流的开关； 若变换器为单向变换器，则多输入串并联切换结构中的开关可以均为双向开关，也可以是以二极管来代替部分双向开关，比如代替连接各个输入端正极的开关，或者代替连接各个输入端负极的开关。
该后级的变换器包括：电感和电容；电容的两端与多端口复用单元的输出端正负极相连。
具体的，如图11d输入端SHn的正极依次通过第一开关和第二开关与输入端SHn的负极相连；电感的一端与第一开关和第二开关之间的连接点相连；电感的另一端分别与电容的一端和输出端SOUTn的正极相连；输入端SHn的负极还与第三开关和第四开关之间的连接点相连；输入端SLn的正极依次通过第三开关和第四开关与输入端SLn的负极相连；输入端SLn的负极还与电容的另一端和输出端SOUTn的负极相连。因为多输入耦合支路后级的变换器，作为一个变压器，本身即可实现增益调节，因此多端口复用单元的采用10d所示的结构可进一步降低前级变换器增益范围要求，同时可实现电压连续调节。
在多端口复用单元的为单向变换时，其结构还可以为如图11e所示的结构，将第一开关和第四开关替换为二极管，其具体连接关系，在此不再一一赘述，均在本申请的保护范围内；也可以为如图11f所示的结构，将第二开关和第三开关替换为二极管，其具体连接关系，在此不再一一赘述，均在本申请的保护范围内。将两个开关使用两个二极管替代，进而降低成本。
需要说明的是，针对多输入单输出的情况，可采用图11a至图11f所示的几种方案进行搭配组合，获得较为灵活且种类繁多方案。如图12a至图12c所示为几种6输入1输出的结构；如图12a所示的结构为：先使用如图11b所示结构将三个模组并联后，再将并联后单元使用如图11d所示的结构级联；如图12b所示的结构为：先使用如图11b所示的结构将三个模组并联后，再将并联后单元使用如图11c所示的结构实现串联切换；如图12c所示为结构为：先使用如图11b所示结构将每两个模组单元并联后，再使用如图11d所示的结构采用三级级联输出方案；其他组合方式在此不再一一赘述，均在本申请的保护范围内。输入的数量也不做具体限定，视实际情况而定即可，均在本申请的保护范围内。
值得说明的是，上述相应实施例中均能确保每一组低压整流单元由相应高压变换单元直接耦合，但无法保证每一个高压变换单元能量均衡；因此，在实际应用中，在各模组单元均存在至少一个低压整流单元与其他模组单元对应的低压整流单元保持输出端共母线连接的情况下，使各个多绕组变压器中，均存在至少一个所述副边绕组，通过相应的低压整流单元及公共母线，分别与其他各个多绕组变压器中相应副边绕组存在间接连接关系；从而可以利用共母线的特性实现每一高压变换单元以及低压整流单元的能量均衡。
如图8a-图8d所示，图8a为部分共母线和另一部分独立输出的示意图，具体的，如图8a所示，Vout11、Vout21……Voutm1共母线连接，Vout12、Vout22……Voutm2共母线连接，……，Vout1i、Vout2i……Voutmi共母线连接；剩余的副边绕组均通过相应的低压整流单元独立输出，如Vout1(i+1)、Vout2(i+1)……Voutm(i+1)独立输出，Vout1(i+2)、Vout2(i+2)……Voutm(i+2)独立输出，……，Vout1n、Vout2 n……Voutm n独立输出。当然，也可以是全部共母线的情况(未进行图示)，在此不再一一赘述，均在本申请的保护范围内。
以每个模组单元具有4个副边绕组、每个副边绕组分配有独立的低压整流单元为例进行说明，每个模组单元对应4个低压整流单元的输出端，其中，部分共母线，另一部分独立输出的情况：只有3路输出端分别与三个多端口复用单元的相应输入端相连，各个模组单元剩余的另一个输出端分别与相应多端口复用单元的输出端连接；从而实现至少一组副边绕组共母线连接，以及至少一组副边绕组独立输出；全部共母线的情况：4路输出端分别与四个多端口复用单元的相应输入端相连，其他低压整流单元的输出端也与这四个多端口复用单元的相应输入端，也即，每个模组单元的4个低压整流单元的输出端与其他的模组单元的4个低压整流单元的输出端分别对应共母线连接。
为了便于说明，以图8b所示的特例情况，来说明如何实现能量的均衡。
具体的，如图8b(图8b中以副边绕组个数为2，模组单元个数为3为例进行展示)所示，模组1中的一个副边绕组与低压整流单元A/D-S11的交流侧相连；模组1中的另一个副边绕组与低压整流单元A/D-S12的交流侧相连；低压整流单元A/D-S11的直流侧作为自身的输出端Vout11；低压整流单元 A/D-S12的直流侧作为自身的输出端Vout12。模组2中的一个副边绕组与低压整流单元A/D-S21的交流侧相连；模组2中的另一个副边绕组与低压整流单元A/D-S22的交流侧相连；低压整流单元A/D-S21的直流侧作为自身的输出端Vout21；低压整流单元A/D-S22的直流侧作为自身的输出端Vout22。模组3中的一个副边绕组与低压整流单元A/D-S31的交流侧相连；模组3中的另一个副边绕组与低压整流单元A/D-S32的交流侧相连；低压整流单元A/D-S31的直流侧作为自身的输出端Vout31；低压整流单元A/D-S32的直流侧作为自身的输出端Vout32。
低压整流单元A/D-S11的输出端Vout11、低压整流单元A/D-S21的输出端Vout21以及低压整流单元A/D-S31的输出端Vout31共母线相连，也即不同各个多绕组变压器中的相应各个副边绕组，均通过相应的低压整流单元实现间接共母线相连；低压整流单元A/D-S12的输出端Vout12、低压整流单元A/D-S22的输出端Vout22以及低压整流单元A/D-S32的输出端Vout32独立输出。
具体的，图8b中箭头线表示在仅低压整流单元A/D-S12的输出端Vout12有输出能量需求时的能量流向。模组2、3的高压变换单元分别通过其共母线的低压整流单元向共母线提供总输出1/3能量，再通过模组1的输出端Vout11将2/3能量传递至低压整流单元A/D-S12的输出端Vout12，模组1的高压变换单元直接向低压整流单元A/D-S12的输出端Vout12提供另外的1/3能量，以此来保证高压变换单元的能量均衡。
在实际应用中，共母线相连的各个副边绕组，还可以通过公共母线与外部电源相连。如图8c和图8d所示，低压整流单元A/D-S11的输出端Vout11、低压整流单元A/D-S21的输出端Vout21以及低压整流单元A/D-S31的输出端Vout31通过公共母线与直流电源DC相连。
如图8c则提供了一种低压母线，即公共母线，有额外能量输入时的情况，高压变换单元分别提供相同的能量，而低压侧的公共母线提供额外能量平衡。如图8d则提供了一种更为极限的情况，高压变换单元不提供能量，独立输出的能量完全由低压侧的额外能量输入提供。
需要说明的是，图8a-图8c均为部分共母线的连接关系，对于全部共母线的连接关系及其工作原理，与图8a-图8c所对应的描述相似，在此不再一一赘 述，均在本申请的保护范围内。
需要说明的是，低压整流单元是双向的，上述内容中将其交流侧记为输入端，将其直流侧记为输出端。
在本实施例中，利用公共母线来实现多组低压整流单元的能量协调，从而在保证高压变换单元能量均衡的同时降低系统复杂度、减少低压整流单元数量；为系统提供的公共低压母线可以为其他能源接入、提供方便，便于实现诸如光储充耦合，提高系统的复用性；在保证至少一组低压整流单元共母线的情况下，其他组低压整流单元与其中部分低压整流单元之间独立，从而可以利用共母线的特性实现每一高压变换单元以及低压整流单元的能量均衡。
当然，实际应用中并不排除存在至少一个额外的冗余模组单元与其他模组单元间不存在低压整流单元的输出端共母线连接关系的可能性，如图15所示的模组m+1，视其具体应用环境而定即可，均在本申请的保护范围内。
本实施例提供的该级联式多端口变换器，从低压侧看，各个多绕组变压器分别为各自对应的多个低压侧输出提供副边绕组；而对于共母线相连的各个低压整流电压，其对应的低压侧总输出通过多端口复用单元由相应各个高压变换单元输出汇总而来；从高压侧看，各个高压变换单元均与相应的多绕组变压器的原边绕组连接；从而保证了多个低压侧输出端(如图3-图6所示的Vout1-Vouti)的能量均来自于对应多个高压变换单元，而多个副边绕组之间本身可以较为容易实现绝缘，以满足绝缘需求；同时多个低压侧可通过低压整流单元，或者，低压整流单元和多端口复用单元实现对总输出电压的独立控制。
本发明实施例提供一种三相中压输入系统，如图13所示，包括：三个相单元，相单元包括：电感和上述任一实施例提供的级联式多端口变换器；其中：
各个相单元的输入端首端直接与中压电网相连；各个相单元的输入端尾端相连。每个相单元采用相同方式连接，使得每一个相单元的低压侧输出能量均与三相级联系统中所有单元实现直接耦合。相单元中，级联式多端口变换器的输入端首端与电感的一端相连；电感的另一端作为相单元的输入端首端；级联式多端口变换器的输入端尾端作为相单元的输入端尾端。
在实际应用中，在各个相单元中级联式多端口的低压整流单元与多个独立 的副边绕组相连时，该低压整流单元可以与不同相单元中独立的副边绕组相连，也可以是同一相单元中独立的副边绕组相连，例如，第1个低压整流单元分别与第1个相单元的中一个副边绕组和第2个相单元的中一个副边绕组相连，且这两个副边绕组独立；在此不再一一赘述，只要确保与同一个低压整流单元相连的各个副边绕组独立即可，不限定这些副边绕组是否来源于同一个相单元，也不限定是否来源于同一多绕组变压器，各个低压整流单元的具体连接关系，视实际情况而定即可，均在本申请的保护范围内。
需要说明的是，全部级联式多端口变换器可以共用同一组多端口复用单元；各个级联式多端口变换器也可以有各自的一组多端口复用单元。
在实际应用中，各个级联式多端口变换器的结构可以相同，也可以不同；图13所示的结构仅为一种示例，级联式多端口变换器分别采用其他结构的示意图，可以参考上述实施例。
该级联式多端口变换器的具体结构及工作原理，详情参见上述实施例，在此不再一一赘述，均在本申请的保护范围内。需要说明的是，该级联式多端口变换器也可以应用于其他系统，在此不再一一赘述，均在本申请的保护范围内。
在本实施例中，多个独立的副边绕组共用同一个低压整流单元，进而减少低压整流单元的总数量，从而改善三相中压输入系统复杂度及成本，使得三相中压输入系统更高功率密度、更低成本、更高效率。
本发明实施例提供一种三相中压输入系统，如图14所示，包括：MMC变换器和N个直流变换单元，该直流变换单元包括：电感和上述任一实施例提供的级联式多端口变换器；N为正整数。
各个直流变换单元的输入端首端与MMC变换器的直流侧正极相连；各个直流变换单元的输入端尾端与MMC变换器的直流侧负极相连。MMC变换器的交流侧与中压电网相连。
直流变换单元中，级联式多端口变换器的输入端首端与电感的一端相连；电感的另一端作为直流变换单元的输入端首端；级联式多端口变换器的输入端尾端作为直流变换单元的输入端尾端。
需要说明的是，各个直流变换单元的输入端通过MMC变换器与中压电网相连；即高压侧先采用MMC变换器构建高压直流母线，再从高压直流母线经级联的方式与至少两个端口为相互隔离的低压直流电源进行能量交互，多个端口均实现直接能量耦合。
直流变换单元中级联式多端口变换器的第一AC/DC变换器由两根直通引线代替。
在实际应用中，在各个直流变换单元中级联式多端口的低压整流单元与多个独立的副边绕组相连时，该低压整流单元可以与不同直流变换单元中独立的副边绕组相连，也可以是同一直流变换单元中独立的副边绕组相连，例如，第1个低压整流单元分别与第1个直流变换单元的中一个副边绕组和第2个直流变换单元的中一个副边绕组相连，且这两个副边绕组独立；在此不再一一赘述，只要确保与同一个低压整流单元相连的各个副边绕组独立即可，不限定这些副边绕组是否来源于同一个直流变换单元，也不限定是否来源于同一多绕组变压器，各个低压整流单元的具体连接关系，视实际情况而定即可，均在本申请的保护范围内。
需要说明的是，全部级联式多端口变换器可以共用同一组多端口复用单元；各个级联式多端口变换器也可以有各自的一组多端口复用单元。
在实际应用中，各个级联式多端口变换器的结构可以相同，也可以不同；图14所示的结构仅为一种示例，级联式多端口变换器分别采用其他结构的示意图，可以参考上述实施例。
该级联式多端口变换器的具体结构及工作原理，详情参见上述实施例，在此不再一一赘述，均在本申请的保护范围内。需要说明的是，该级联式多端口变换器也可以应用于其他系统，在此不再一一赘述，均在本申请的保护范围内。
在本实施例中，多个独立的副边绕组共用同一个低压整流单元，进而减少低压整流单元的总数量，从而改善N相中压输入系统复杂度及成本，使得三相中压输入系统更高功率密度、更低成本、更高效率。
本说明书中的各个实施例中记载的特征可以相互替换或者组合，各个实施例之间相同相似的部分互相参见即可，每个实施例重点说明的都是与其他实施 例的不同之处。尤其，对于系统或系统实施例而言，由于其基本相似于方法实施例，所以描述得比较简单，相关之处参见方法实施例的部分说明即可。以上所描述的系统及系统实施例仅仅是示意性的，其中所述作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部模块来实现本实施例方案的目的。本领域普通技术人员在不付出创造性劳动的情况下，即可以理解并实施。
专业人员还可以进一步意识到，结合本文中所公开的实施例描述的各示例的单元及算法步骤，能够以电子硬件、计算机软件或者二者的结合来实现，为了清楚地说明硬件和软件的可互换性，在上述说明中已经按照功能一般性地描述了各示例的组成及步骤。这些功能究竟以硬件还是软件方式来执行，取决于技术方案的特定应用和设计约束条件。专业技术人员可以对每个特定的应用来使用不同方法来实现所描述的功能，但是这种实现不应认为超出本发明的范围。
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的精神或范围的情况下，在其它实施例中实现。因此，本发明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。

Claims (21)

  1. 一种级联式多端口变换器，其特征在于，包括：多个模组单元和多个低压整流单元，所述模组单元包括：至少一个多绕组变压器和多个高压变换单元；
    各个所述模组单元的输入端级联，级联后的两端作为所述级联式多端口变换器的输入端两端口；
    所述模组单元中：各个所述高压变换单元的输入端级联，级联后的两端作为所述模组单元的输入端两端口；所述多绕组变压器中的磁芯上绕制有多个原边绕组和至少一个副边绕组；各个所述高压变换单元的输出端分别与相应的所述原边绕组相连；所述副边绕组与相应的所述低压整流单元的对应输入端相连。
  2. 根据权利要求1所述的级联式多端口变换器，其特征在于，所述低压整流单元的个数等于全部所述副边绕组的总个数，各个所述副边绕组与各个所述低压整流单元的输入端一一对应连接。
  3. 根据权利要求1所述的级联式多端口变换器，其特征在于，所述低压整流单元的个数小于全部所述副边绕组的总个数，多个独立的所述副边绕组共用同一个所述低压整流单元。
  4. 根据权利要求3所述的级联式多端口变换器，其特征在于，多个独立的所述副边绕组，包括：不同所述多绕组变压器的副边绕组；和/或，同一所述多绕组变压器中不同磁柱上的副边绕组。
  5. 根据权利要求3所述的级联式多端口变换器，其特征在于，多个独立的所述副边绕组，串联连接于共用的所述低压整流单元的输入端，或者，并联连接于共用的所述低压整流单元的输入端。
  6. 根据权利要求1-5任一所述的级联式多端口变换器，其特征在于，相应的所述低压整流单元的输出端之间共母线连接，以使至少一个所述多绕组变压器中，均存在至少一个所述副边绕组，分别与其他至少一个所述多绕组变压器中相应所述副边绕组存在间接连接关系。
  7. 根据权利要求6所述的级联式多端口变换器，其特征在于，各个所述 多绕组变压器中，均存在至少一个所述副边绕组，通过相应的所述低压整流单元及公共母线，分别与其他各个所述多绕组变压器中相应所述副边绕组存在间接连接关系。
  8. 根据权利要求6所述的级联式多端口变换器，其特征在于，共母线相连的各个所述副边绕组，还通过公共母线与外部电源相连。
  9. 根据权利要求6所述的级联式多端口变换器，其特征在于，共母线相连的低压整流单元所连接的各个多绕组变压器中，各个所述模组单元，其内部的副边绕组均用于与其他对应副边绕组实现间接共母线连接。
  10. 根据权利要求6所述的级联式多端口变换器，其特征在于，还包括：至少一个额外的冗余模组单元；
    所述冗余模组单元内的各个副边绕组均通过相应的低压整流单元独立输出。
  11. 根据权利要求1-5任一所述的级联式多端口变换器，其特征在于，还包括：多个多端口复用单元；
    所述多端口复用单元的各个输入端分别与不同低压整流单元的相应输出端相连。
  12. 根据权利要求11所述的级联式多端口变换器，其特征在于，所述多端口复用单元包括：多输入耦合支路，或者，多输入耦合支路及其后级的变换器。
  13. 根据权利要求12所述的级联式多端口变换器，其特征在于，所述多输入耦合支路为以下至少一种：多输入串联结构、多输入并联结构及多输入串并联切换结构。
  14. 根据权利要求13所述的级联式多端口变换器，其特征在于，所述多端口复用单元包括多输入耦合支路及其后级的变换器，且所述多输入耦合支路包括所述多输入串并联切换结构时：
    所述多输入串并联切换结构中的开关均为双向开关。
  15. 根据权利要求14所述的级联式多端口变换器，其特征在于，若所述变换器为单向变换器，则所述多输入串并联切换结构中连接输入端正极或负极的双向开关由二极管替代。
  16. 根据权利要求1-5任一所述的级联式多端口变换器，其特征在于，所述高压变换单元，包括：DC/AC变换器和第一AC/DC变换器；
    所述第一AC/DC变换器的交流侧作为所述高压变换单元的输入端；
    所述第一AC/DC变换器的直流侧与所述DC/AC变换器的直流侧相连；
    所述DC/AC变换器的交流侧作为所述高压变换单元的输出端。
  17. 根据权利要求16所述的级联式多端口变换器，其特征在于，所述第一AC/DC变换器为全桥式结构或半桥式结构。
  18. 根据权利要求16所述的级联式多端口变换器，其特征在于，所述低压整流单元，包括：第二AC/DC变换器；
    所述第二AC/DC变换器的交流侧作为所述低压整流单元的输入端；
    所述第二AC/DC变换器的直流侧作为所述低压整流单元的输出端。
  19. 根据权利要求18所述的级联式多端口变换器，其特征在于，所述DC/AC变换器通过相应绕组与所述第二AC/DC变换器所构成的结构是：双有源桥结构、LLC结构及CLLC结构中的任意一种。
  20. 一种三相中压输入系统，其特征在于，包括：三个相单元，所述相单元包括：电感和如权利要求1-19任一所述的级联式多端口变换器；其中：
    各个所述相单元的输入端首端与中压电网相连；
    各个所述相单元的输入端尾端相连；
    所述相单元中，所述级联式多端口变换器的输入端首端与所述电感的一端相连；所述电感的另一端作为所述相单元的输入端首端；所述级联式多端口变换器的输入端尾端作为所述相单元的输入端尾端。
  21. 一种三相中压输入系统，其特征在于，包括：MMC变换器和N个直流变换单元，所述直流变换单元包括：电感和如权利要求1-19任一所述的级联式多端口变换器；N为正整数；
    各个所述直流变换单元的输入端首端与所述MMC变换器的直流侧正极相连；
    各个所述直流变换单元的输入端尾端与所述MMC变换器的直流侧负极相连；
    所述MMC变换器的交流侧与中压电网相连；
    所述直流变换单元中，所述级联式多端口变换器的输入端首端与所述电感的一端相连；所述电感的另一端作为所述直流变换单元的输入端首端；所述级联式多端口变换器的输入端尾端作为所述直流变换单元的输入端尾端；
    所述直流变换单元中所述级联式多端口变换器的第一AC/DC变换器由两根直通引线代替。
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