WO2016029824A1 - 一种直流电压变换装置及其桥臂控制方法 - Google Patents

一种直流电压变换装置及其桥臂控制方法 Download PDF

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Publication number
WO2016029824A1
WO2016029824A1 PCT/CN2015/087796 CN2015087796W WO2016029824A1 WO 2016029824 A1 WO2016029824 A1 WO 2016029824A1 CN 2015087796 W CN2015087796 W CN 2015087796W WO 2016029824 A1 WO2016029824 A1 WO 2016029824A1
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Prior art keywords
cascade structure
module
sub
voltage
cascade
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PCT/CN2015/087796
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English (en)
French (fr)
Inventor
杨杰
贺之渊
汤广福
庞辉
***
Original Assignee
国家电网公司
国网智能电网研究院
中电普瑞电力工程有限公司
国网浙江省电力公司
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Priority claimed from CN201410421629.3A external-priority patent/CN105375757B/zh
Priority claimed from CN201510153175.0A external-priority patent/CN106160463B/zh
Application filed by 国家电网公司, 国网智能电网研究院, 中电普瑞电力工程有限公司, 国网浙江省电力公司 filed Critical 国家电网公司
Publication of WO2016029824A1 publication Critical patent/WO2016029824A1/zh

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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS 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
    • H02M3/00Conversion of dc power input into dc power output
    • H02M3/02Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10Conversion 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
    • H02M3/145Conversion 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
    • H02M3/155Conversion 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
    • H02M3/156Conversion 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
    • H02M3/158Conversion 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
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS 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
    • H02M7/00Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483Converters with outputs that each can have more than two voltages levels
    • H02M7/4835Converters with outputs that each can have more than two voltages levels comprising two or more cells, each including a switchable capacitor, the capacitors having a nominal charge voltage which corresponds to a given fraction of the input voltage, and the capacitors being selectively connected in series to determine the instantaneous output voltage
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS 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
    • H02M7/00Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483Converters with outputs that each can have more than two voltages levels
    • H02M7/4837Flying capacitor converters
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS 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
    • H02M1/00Details of apparatus for conversion
    • H02M1/0095Hybrid converter topologies, e.g. NPC mixed with flying capacitor, thyristor converter mixed with MMC or charge pump mixed with buck
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS 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
    • H02M3/00Conversion of dc power input into dc power output
    • H02M3/02Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10Conversion 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
    • H02M3/145Conversion 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
    • H02M3/155Conversion 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
    • H02M3/156Conversion 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
    • H02M3/158Conversion 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
    • H02M3/1584Conversion 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 with a plurality of power processing stages connected in parallel

Definitions

  • the invention relates to a voltage conversion device in the field of flexible direct current transmission, in particular to a direct current voltage conversion device and a bridge arm control method thereof.
  • DC grid technology has no transmission distance limitation, no reactive power compensation equipment, strong flexibility and controllability, and can provide power supply for large cities and offshore wind power access. Good solutions have broad application prospects.
  • DC grid technology faces a voltage level conversion problem similar to that of an AC grid, and the research on DC voltage converters is still in a preliminary stage worldwide.
  • the main features of the DC voltage converter are as follows:
  • a wide range of voltage ratios can be achieved.
  • the diversity of DC voltage levels requires voltage converters to achieve a wide range of voltage ratios to meet the requirements of different applications;
  • a good DC transformer should meet the DC fault condition on one side and not affect the operation on the other side, that is, it has fault isolation capability;
  • a good DC transformer should have a low investment and a low loss level, and the corresponding components should not be too large to cause excessive land occupation.
  • the “Modular Multilevel DC/DC converter for HVDC applications” patent of WO 2014/056540 A1 discloses a novel DC-DC transformer topology of high voltage direct current transmission, in which a two-terminal module in a "face-to-face” topology is shared, effectively reducing The number, sub-modules, and footprint of the sub-modules that the system inputs are used, but the transformer isolation potential must be used.
  • the "Bidirectional Unisolated DC-DC converter based on cascaded cells" patent of WO 2013/026477 A1 discloses a bidirectional isolated DC-DC transformer based on a cascading battery, wherein the disclosed modular multi-level structure directly converted to DC, The transformer is eliminated, which effectively reduces the investment and land occupation.
  • the output on the low-voltage side still needs a large reactor or a conjugate reactor, and at the same time, for the fault isolation, an additional full-bridge sub-module is required.
  • the traditional low-voltage topology is difficult to apply to the high-voltage field.
  • the DC-DC transformer based on modular multi-level technology has received wide attention from its good expansion performance.
  • "face-to-face" type DC transformer based on modular multi-level technology connecting two AC/DC modular multi-level converters through AC transformer to carry out voltage conversion, which not only occupies a large area, but also has high cost and high loss. It is difficult to carry out extensive promotion.
  • an object of the present invention is to provide a DC voltage conversion device and a bridge arm control method thereof.
  • the technical solution provided by the present invention adopts a method in which a device serial structure and a sub-module are cascaded, Transformer In the case of voltage conversion, it also enables soft switching of series devices and reduces investment and footprint.
  • a brief summary is given below. This generalization is not a general comment, nor is it intended to identify key/critical constituent elements or to describe the scope of protection of these embodiments. Its sole purpose is to present some concepts in a simplified form as a prelude to the following detailed description.
  • the invention provides a DC voltage conversion device, which is a single-phase, two-phase or two-phase structure, each phase consisting of a basic functional module, the improvement being that the basic functional module comprises a series device cascade Structure and submodule cascade structure.
  • the basic functional module includes two sets of device cascade structures S1 and S4 and a sub-module cascade structure connected in a star shape; one end of the sub-module cascade structure and one end of the device cascade structure S1 and the device respectively One end of the cascade structure S4 is connected; the other end of the device cascade structure S1 is connected to a low voltage terminal, the other end of the device cascade structure S4 is connected to a ground point; the other end of the sub-module cascade structure is connected to High voltage terminal.
  • the basic functional module includes two sets of device cascade structures S1 and S4 and a sub-module cascade structure connected in a star shape; one end of the sub-module cascade structure and one end of the device cascade structure S1 and the device respectively One end of the cascade structure S4 is connected; the other end of the device cascade structure S1 is connected to a high voltage terminal, and the other end of the device cascade structure S4 is connected to a low voltage terminal; the other end of the submodule cascade structure is connected to Grounding point.
  • the basic functional module includes four sets of device cascade structures S1, S4', S1' and S4 and a sub-module cascade structure; the device cascade structures S1 and S4' are connected between the high voltage terminal and the low voltage terminal The other two device cascade structures S1' and S4 are connected between the low voltage terminal and the ground point; one end of the submodule cascade structure is connected to the connection point between the device cascade structures S1 and S4', and the other end is connected to A connection point between the device cascade structure S1' and S4.
  • the device cascade structure is composed of a plurality of power electronic devices connected in series, the power electronic devices including fully-controlled devices (such as IGBT, GTO, etc.) and their anti-parallel diodes, semi-controlled devices (such as thyristors, etc.) Or a diode.
  • fully-controlled devices such as IGBT, GTO, etc.
  • semi-controlled devices such as thyristors, etc.
  • diode a diode.
  • the sub-module cascade structure is composed of a plurality of half-bridge sub-module cascade structures and a reactor in series, a full-bridge sub-module cascade structure and a reactor are connected in series or a full-bridge sub-module cascade structure and a half bridge
  • the module cascade structure is composed of a full bridge type device which is connected in series with a capacitor in parallel; the full bridge submodule is composed of an H bridge and a capacitor in parallel; each bridge arm of the H bridge is composed of Controlled devices (such as IGBT, GTO, etc.); each fully controlled device is anti-parallel diode.
  • the device includes at least two basic functional modules, a two-phase structure or a two-phase or more structure, that is, a transform unit, whose operating frequency is a fundamental frequency or a high frequency is formed.
  • the device cascade structure when the device cascade structure is turned on or off, the number of inputs of the sub-module cascade structure is adjusted, and the soft switching function of the device cascade structure is realized.
  • the invention also provides a bridge arm control method for a DC voltage conversion device, wherein the basic function module in the DC voltage conversion device realizes voltage conversion by bridge arm control; the improvement is that the method is based on the connection of the basic function module
  • Different ways include the following implementations:
  • the basic functional module comprises two sets of device cascade structures S1 and S4 and a sub-module cascade structure connected in a star shape; one end of the sub-module cascade structure is respectively connected with one end of the device cascade structure S1 and a device level One end of the connected structure S4 is connected; the other end of the device cascade structure S1 is connected to the low voltage terminal, and the other end of the device cascade structure S4 is connected to the ground Point; the other end of the sub-module cascade structure is connected to the high voltage terminal; when the device cascade structure S1 is turned on, the device cascade structure S4 is turned off, and the low voltage terminal positive current enters the submodule through the device cascade structure S1 Cascade structure, the voltage outputted by the cascaded structure of the sub-module is a voltage of a high voltage terminal minus a voltage of a low voltage terminal for compensating for a voltage difference between a high voltage terminal and a low voltage terminal; when the device cascade structure S4 is turned on, the device
  • the current difference between the low voltage end and the high voltage end is injected into the sub-module cascade structure through the device cascade structure S4, and the voltage outputted by the sub-module cascade structure is the high voltage end voltage, which is used for compensating the voltage difference between the high voltage end and the ground;
  • the basic function module includes two sets of device cascade structures S1 and S4 and a sub-module cascade structure connected in a star shape; one end of the sub-module cascade structure and one end of the device cascade structure S1 and the device cascade structure respectively One end of S4 is connected; the other end of the device cascade structure S1 is connected to a high voltage terminal, the other end of the device cascade structure S4 is connected to a low voltage terminal; the other end of the submodule cascade structure is connected to a ground point;
  • the device cascade structure S1 is turned on, the device cascade structure S4 is turned off, and the high voltage terminal positive current enters the submodule cascade structure through the device cascade structure S1, and the output voltage of the submodule cascade structure is The high voltage terminal voltage is used to compensate the voltage difference between the high voltage terminal and the ground; when the device cascade structure S4 is turned on, the device cascade structure S1 is turned off, and the low voltage terminal current is injected into the submodule cascade through the device
  • the basic functional module comprises four sets of device cascade structures S1, S4', S1' and S4 and a sub-module cascade structure connected in a star shape; the device cascade structures S1 and S4' are connected to the high voltage terminal and Between the low voltage terminals, the other two device cascade structures S1' and S4 are connected between the low voltage terminal and the ground point; one end of the submodule cascade structure is connected to the connection point between the device cascade structures S1 and S4'. The other end is connected to a connection point between the device cascade structures S1' and S4; when the device cascade structures S1 and S1' are turned on, the device cascade structures S4 and S4' are turned off, and the high voltage terminal positive current passes.
  • the device cascade structures S1 and S1' enter the sub-module cascade structure, and the output voltage of the sub-module cascade structure shown is a high voltage terminal voltage minus a low voltage terminal voltage for compensating for a voltage difference between the high voltage terminal and the low voltage terminal;
  • the junction structures S4 and S4' are turned on, the device cascade structures S1 and S1' are turned off, and the current difference between the low voltage terminal and the high voltage terminal is injected into the sub-module cascade structure through the device cascade structures S4 and S4'.
  • the output voltage of the sub-module cascade structure is the low voltage end Pressure for compensating for the low-side voltage difference.
  • the present invention also provides a DC voltage conversion device, which is improved in that the device includes a basic transformation unit composed of a unipolar structure or a bipolar structure that realizes DC power conversion.
  • the basic transformation unit is composed of two or more phase basic functional modules in parallel; and the DC power conversion is realized by the bridge arm control method.
  • the basic functional module includes two device cascade structures and a sub-module cascade structure connected in a star structure;
  • the remaining end of one of the device cascade structures is connected to the high voltage terminal positive terminal, and the remaining end of the other device cascade structure is connected to the ground point; the remaining end of the submodule cascade structure is connected to the low voltage terminal positive terminal.
  • the basic function module constitutes a multi-DC terminal basic function module having a plurality of DC voltage conversion capabilities by an additional sub-module cascade structure.
  • the device cascade structure is formed by a single control device and one of an anti-parallel diode, a half bridge submodule, and a full bridge submodule structure, or a plurality of them are connected in series. Or formed by the series inductance of the above structure; in the absence of power reverse demand, the full control type of the upper or lower arm in the basic functional module formed by the fully controlled device and its anti-parallel diode is omitted.
  • the device becomes a diode cascade or a series arrangement of diodes and inductors.
  • sub-module cascade structure is composed of a plurality of full bridge submodules or half bridge submodules, or multiple full bridges
  • the submodule or half bridge submodule is composed of a series connected inductor.
  • the full bridge sub-module is composed of an H-bridge shunt capacitor bank, and each bridge arm of the H-bridge is composed of a full-control device module and a diode connected in anti-parallel with the same, and the half-bridge sub-module is connected in parallel by a single-phase bridge arm.
  • a capacitor bank consisting of the upper and lower bridge arms, each of the bridge arm submodules being composed of a full control device module and a diode connected in anti-parallel thereto;
  • the full control device module is composed of a single full control device, or a full control device connected in series or in parallel, the capacitor group being composed of a single capacitor, or a plurality of capacitors connected in series or in parallel.
  • the invention also provides a bridge arm control method for a DC voltage conversion device, which is improved in that when the basic transformation unit is a single-phase basic function module, the bridge arm control method comprises the following steps:
  • the on-time of the upper arm and the lower arm of the basic function module are designed according to the balance setting manner, and the switching frequency setting range of the upper arm and the lower arm of the basic function module is not limited.
  • the balance setting mode adjusts the ratio of the opening time of the upper arm and the lower arm of the corresponding basic function module according to the voltage or energy fluctuation of the sub-module cascade structure.
  • the output of the sub-module cascade structure is adjusted to be soft-switched.
  • the technical solution provided by the present invention can realize a wide range of voltage conversion ratios.
  • the diversity of DC voltage levels requires voltage converters to achieve a wide range of voltage ratios to meet the requirements of different applications;
  • a good DC transformer should meet the DC fault condition on one side, and the operation on the other side is not affected, that is, it has fault isolation capability;
  • a good DC transformer should have a low investment and a low loss level, and the corresponding components should not be too large to cause excessive land occupation.
  • the DC voltage conversion device provided by the invention only uses IGBT series structure and a certain number of sub-modules to realize voltage conversion in series, with less investment and small loss, and at the same time, low-frequency operation has less improvement on loss; good DC transformer should be invested less With low loss levels;
  • the DC voltage conversion device provided by the invention has high voltage and current quality on the DC side, and no other filter is needed;
  • the DC voltage conversion device provided by the invention can effectively realize fault isolation; a good DC transformer should meet the DC fault condition on one side, and the operation on the other side is not affected, that is, it has fault isolation capability;
  • the DC voltage conversion device provided by the present invention has a wide range of variation ratio and a wide range of voltage conversion ratios.
  • the diversity of DC voltage levels requires voltage converters to achieve a wide range of voltage ratios to meet the requirements of different applications.
  • the DC voltage conversion device provided by the present invention has power flow capability. Due to the flexibility requirement of DC power regulation, correspondingly, the DC voltage converter needs to have bidirectional power adjustment capability.
  • FIG. 1 is a structural diagram of a half bridge or full bridge submodule provided by the present invention, wherein (a) is a half bridge submodule structure; (b) is a full bridge submodule structure;
  • FIG. 2 is a structural diagram of a basic function module provided by the present invention, wherein (a) is a basic functional module structure diagram 1; (b) is a basic function module structure diagram 2; (c) is a basic function module structure diagram 3;
  • FIG. 3 is a structural diagram of a three-phase transform unit provided by the present invention, wherein (a) is a three-phase transform unit structure diagram 1; (b) is a three-phase transform unit structure diagram 2; (c) is a three-phase transform unit structure diagram 3 .
  • FIG. 5 is a diagram showing the working mechanism of the basic function module provided by the present invention (multiple DC terminals);
  • FIG. 7 is a topological structural diagram of a multiphase transform unit provided by the present invention.
  • FIG. 9 is a structural diagram of a three-phase basic conversion unit of a three-DC terminal provided by the present invention.
  • the invention provides a DC voltage conversion device, which is a single-phase or multi-phase structure, each phase is composed of basic functional modules, including a device cascade structure and a sub-module cascade structure in series;
  • the basic functional module includes two sets of device cascade structures S1 and S4 and a sub-module cascade structure connected in a star shape; one end of the sub-module cascade structure is respectively cascaded with the device.
  • One end of the device and one end of the structure S1 S4 cascade structure is connected; the other end of the cascade structure of the device S1 is connected to low-voltage terminal (V L), the other end of the cascade structure device S4 is connected to ground; the The other end of the sub-module cascade structure is connected to the high voltage terminal (V H ).
  • the basic functional module includes two sets of device cascade structures S1 and S4 and a sub-module cascade structure connected in a star shape; one end of the sub-module cascade structure is respectively cascaded with the device One end of the structure S1 is connected to one end of the device cascade structure S4; the other end of the device cascade structure S1 is connected to a high voltage terminal (V H ), and the other end of the device cascade structure S4 is connected to a low voltage terminal (V L The other end of the sub-module cascade structure is connected to a ground point.
  • V H high voltage terminal
  • V L low voltage terminal
  • the basic functional module includes four sets of device cascade structures S1, S4', S1', and S4 and a sub-module cascade structure connected in a star shape; the device cascade structure S1 and S4' is connected between the high voltage terminal (V H ) and the low voltage terminal (V L ), and the other two device cascade structures S1' and S4 are connected between the low voltage terminal (V L ) and the ground point; One end of the junction structure is connected to the connection point between the device cascade structures S1 and S4', and the other end is connected to the connection point between the device cascade structures S1' and S4.
  • the device cascade structure is composed of a plurality of power electronic devices connected in series, the power electronic devices including fully controlled devices (such as IGBT, GTO, etc.) and their anti-parallel diodes, semi-controlled devices (such as thyristors, etc.) or diodes.
  • fully controlled devices such as IGBT, GTO, etc.
  • semi-controlled devices such as thyristors, etc.
  • the sub-module cascade structure is composed of a plurality of half-bridge sub-module cascade structures and reactors in series or a full-bridge sub-module cascade structure and a reactor connected in series, and the half-bridge sub-module is composed of a fully-controlled device series branch and a capacitor Parallel composition; the full bridge sub-module is composed of an H-bridge and a capacitor in parallel; each bridge arm of the H-bridge is composed of a fully-controlled device; each fully-controlled device (such as IGBT, GTO, etc.) is anti-parallel diode
  • the structure diagram of the half bridge or full bridge submodule is shown in Figures 1(a) and (b).
  • the basic function module can be extended to a two-phase structure, or the number of phases can be increased to three-phase or even more phases, and the three-phase transformation unit structure diagram is as shown in Figs. 3(a), (b) and (c), thereby forming a transformation unit.
  • the transform unit can in turn form a parallel or bipolar structure.
  • the operating frequency of the transform unit is not limited to the fundamental frequency, and may also be a high frequency operation.
  • Another advantageous feature of the DC converter topology of the present invention is that the soft switching of the device cascade structure can be effectively realized by adjusting the number of sub-module cascade inputs when the device cascade structure is turned on or off.
  • the invention also provides a bridge arm control method for a DC voltage conversion device, wherein the basic function module in the DC voltage conversion device realizes voltage conversion by bridge arm control;
  • the device cascade structure S1 when the device cascade structure S1 is turned on, the device cascade structure S4 is turned off, and the low-voltage terminal positive current enters the sub-module level through the device cascade structure S1.
  • the connection structure, the output voltage of the sub-module cascade structure is a high voltage terminal voltage minus a low voltage terminal voltage, used to compensate a voltage difference between the high voltage terminal and the low voltage terminal; when the device cascade structure S4 is turned on, the device cascade structure S1 is turned off.
  • the current difference between the low voltage end and the high voltage end is injected into the sub-module cascade structure through the device cascade structure S4, and the voltage outputted by the sub-module cascade structure is a negative high voltage terminal voltage, which is used to compensate the high voltage terminal to ground voltage difference.
  • the device cascade structure S1 when the device cascade structure S1 is turned on, the device cascade structure S4 is turned off, and the high voltage terminal positive current passes through the device cascade structure S1.
  • a module cascade structure wherein the voltage outputted by the cascaded structure of the submodule is a high voltage terminal voltage for compensating for a voltage difference between the high voltage terminal and the ground; when the device cascade structure S4 is turned on, the device cascade structure S1 is closed.
  • the low-voltage terminal current is injected into the sub-module cascade structure through the device cascade structure S4, and the voltage outputted by the sub-module cascade structure is a low-voltage terminal voltage for compensating for the low-voltage side-to-ground voltage difference.
  • the device cascade structures S1 and S1' are turned on, the device cascade structures S4 and S4' are turned off, and the high voltage terminal positive current passes through the device.
  • the cascaded structures S1 and S1' enter the sub-module cascade structure, and the output voltage of the sub-module cascade structure shown is the high-voltage terminal voltage minus the low-voltage terminal voltage, which is used to compensate the high-voltage end and the low voltage.
  • the sub-module cascade structure is injected, and the voltage outputted by the sub-module cascade structure is a low-voltage terminal voltage for compensating for a low-voltage terminal-to-ground voltage difference.
  • the DC voltage conversion device provided by the invention only adopts the device series structure and a certain number of sub-modules to realize voltage conversion in series, with less investment and small loss, and at the same time, the high-frequency operation has less improvement on the loss; the DC-side voltage and current quality at both ends is high. No additional filters are required; power flows in both directions with a wide range of ratios.
  • the invention provides a DC voltage conversion device, which has the following structure: the device comprises a basic transformation unit, and the basic transformation unit comprises a monopole structure or a bipolar structure to realize conversion of DC power.
  • the bipolar structure diagram is shown in Figure 8.
  • the basic transformation unit is composed of two-phase or multi-phase basic functional modules in parallel; the DC power conversion is realized by the bridge arm control method.
  • Fig. 4 is a basic functional block of the device, which is composed of two device cascade structures and one sub-module cascade structure, and the three are connected in a star structure. The other end of one device cascade structure is connected to the high voltage terminal positive terminal, and the other end of the other device cascade structure is connected to the ground point; the remaining end of the submodule cascade structure is connected to the low voltage terminal positive terminal.
  • the basic function module can form a multi-DC terminal basic function module with multiple DC voltage conversion capabilities through an additional sub-module cascade structure, as shown in FIG.
  • the device cascade structure is generally composed of a plurality of fully controlled devices (such as IGBT, GTO, etc.) and its anti-parallel diodes. There may be a series of reactances on the bridge arms. Another alternative is through multiple Figure 1(a).
  • the half bridge or the full bridge submodule shown in Figure 1(b) is connected in series to replace the full control device in series. It is also a feasible solution to mix the full control device with the half bridge and full bridge submodule.
  • the sub-module cascade structure is a series structure of a plurality of half bridge submodules shown in FIG. 1(a) or a full bridge submodule shown in FIG. 1(b), and a reactance may be connected in series on the bridge arm.
  • the full-control device of the upper or lower arm of the device cascade can be omitted, only diode cascade.
  • the sub-module cascade structure is formed by cascading a plurality of half bridge submodules or full bridge submodules, and may include a series inductor.
  • the sub-module is shown in Figure 1(b).
  • the full-control device symbol only represents the function. It can be composed of multiple control devices connected in series or in parallel.
  • the capacitance symbol is only representative of the function. It can also be composed of multiple capacitors connected in series or in parallel. .
  • the invention also provides a bridge arm control method for a DC voltage conversion device.
  • the basic transformation unit is composed of a single-phase basic function module, the working mechanism is as follows:
  • S1a, S2b and S2a, S1b generally operate as complementary pairs.
  • the high-voltage positive current Id1 enters the corresponding sub-module cascade structure through S1a, and the sub-module cascade structure outputs Ud1-Ud2 for compensating for the voltage difference between the high-voltage side and low-voltage side output terminals.
  • the current difference Id2-Id1 between the low voltage end and the high voltage end is injected into the sub-module cascade structure through S2b, and the sub-module cascade structure output -Ud2 is used to compensate the voltage difference between the low-voltage side output terminal and the ground.
  • the high-voltage positive current Id1 enters the corresponding sub-module cascade structure through S2a.
  • the sub-module cascade structure outputs Ud1-Ud2 to compensate the voltage difference between the high-voltage side and low-voltage side output terminals.
  • the current difference Id2-Id1 between the low voltage end and the high voltage end is injected into the sub-module cascade structure through S1b, and the sub-module cascade structure output -Ud2 is used to compensate the voltage difference between the low-voltage side output terminal and the ground.
  • the energy can be kept constant. If the energy of the cascaded structure of the two sub-modules is deviated due to errors, etc., the ratio of the input time of the two complementary pairs can be adjusted. To make adjustments.
  • the basic function module can be extended to the single-phase structure of Fig. 6, or the phase number can be increased to three-phase or even more phases (Fig. 7), thereby forming a basic transformation unit, and the three-phase basic three-phase basic transformation unit structure diagram is as shown in Fig. 9. It can be seen that the basic transformation unit can in turn form a bipolar structure by the form of FIG. At the same time, the operating frequency of the transform unit is not limited to the fundamental frequency, but may also be low frequency and high frequency operation.
  • Another advantageous feature of the topology result of the present invention is that the soft switching of the device cascade structure can be effectively realized by adjusting the number of sub-module cascade structures when the device cascade structure is turned on or off.

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Abstract

一种直流电压变换装置及其桥臂控制方法。该装置为单相、两相或两相以上结构,每相由基本功能模块组成,基本功能模块包括串联的器件级联结构(S1,S4)和子模块级联结构。通过器件串联结构和子模块级联结构相结合,可以在无变压器的情况下实现电压变换,还可实现串联器件的软开关,并减小投资和占地。

Description

一种直流电压变换装置及其桥臂控制方法 技术领域
本发明涉及一种柔性直流输电领域的电压变换装置,具体讲涉及一种直流电压变换装置及其桥臂控制方法。
背景技术
柔性直流技术的迅猛发展使直流电网成为可能,直流电网技术无输电距离限制,不需无功补偿设备,有较强的灵活性和可控性,能为大型城市供电、海上风电接入等提供良好的解决手段,有着广阔的应用前景。
实际应用中,直流电网技术面临与交流电网类似的电压等级变换问题,而对于直流电压变换器的研究,世界范围内尚处于初步阶段。根据直流电网的特性,直流电压变换器的主要特点需求如下:
1、可实现宽范围的电压变比。直流电压等级的多样性,要求电压变换器能够实现宽范围的电压变比,能够满足不同场合的要求;
2、双向功率流动能力。由于直流电网功率调控的灵活性需求,相应的,直流电压变换器需要具备双向功率调节能力;
3、故障隔离能力。良好的直流变压器应满足在一侧发生直流故障情况下,不影响另一侧的运行,即具备故障隔离能力;
4、较低的投资、损耗和占地水平。良好的直流变压器应投资少,具备低损耗水平,同时相应的组件不宜过多导致占地过大。
针对DC-DC变换器已经有了很多的研究成果,在适用于高压领域并采用扩展性良好的模块化多电平技术方向上,“面对面”型模块化多电平变压器是最基础的拓扑形式,该拓扑占地大,而且造价高、损耗大,难以大规模推广应用。
WO2014/056540 A1的“Modular Multilevel DC/DC converter for HVDC applications”号专利披露了一种新型高压直流输电的DC-DC变压器拓扑结构,其中通过共用“面对面”拓扑中的双端子模块,有效减小了***投入的子模块数量、损耗和占地,但必须采用变压器隔离电位。
WO2013/026477 A1的“Bidirectional Unisolated DC-DC converter based on cascaded cells”号专利公开了一种基于级联电池的双向隔离DC-DC变压器,其中披露的直接变换至DC的模块化多电平结构,省去了变压器,有效减小了投资和占地,但在低压侧输出仍需要较大的电抗器或者共轭电抗器,同时针对故障隔离,需要投入额外的全桥子模块。
综上所述,传统的低压拓扑很难应用到高压领域,另一方面,基于模块化多电平技术的DC-DC变压器,以其良好的扩展性能得到大家的广泛关注,然而,最初提出的“面对面”型基于模块化多电平技术的直流变压器,通过交流变压器将两个AC/DC模块化多电平换流器进行连接进行电压变换,不但占地大,而且造价高、损耗大,难以进行大范围推广。
发明内容
为解决上述现有技术中的不足,本发明的目的是提供一种直流电压变换装置及其桥臂控制方法,本发明提供的技术方案通过采用器件串联结构和子模块级联结合的方法,在无变压器的 情况下实现电压变换,同时还可实现串联器件的软开关,并减小投资和占地。为了对披露的实施例的一些方面有一个基本的理解,下面给出了简单的概括。该概括部分不是泛泛评述,也不是要确定关键/重要组成元素或描绘这些实施例的保护范围。其唯一目的是用简单的形式呈现一些概念,以此作为后面的详细说明的序言。
本发明的目的是采用下述技术方案实现的:
本发明提供一种直流电压变换装置,所述装置为单相、两相或两相以上结构,每相由基本功能模块组成,其改进之处在于,所述基本功能模块包括串联的器件级联结构和子模块级联结构。
进一步地,所述基本功能模块包括呈星形连接的两组器件级联结构S1和S4以及子模块级联结构;所述子模块级联结构的一端分别与器件级联结构S1的一端和器件级联结构S4的一端连接;所述器件级联结构S1的另一端连接至低压端子,所述器件级联结构S4的另一端连接至接地点;所述子模块级联结构的另一端连接至高压端子。
进一步地,所述基本功能模块包括呈星形连接的两组器件级联结构S1和S4以及子模块级联结构;所述子模块级联结构的一端分别与器件级联结构S1的一端和器件级联结构S4的一端连接;所述器件级联结构S1的另一端连接至高压端子,所述器件级联结构S4的另一端连接至低压端子;所述子模块级联结构的另一端连接至接地点。
进一步地,所述基本功能模块包括四组器件级联结构S1、S4’、S1’和S4以及子模块级联结构;所述器件级联结构S1和S4’连接于高压端子与低压端子之间,另两组器件级联结构S1’和S4连接于低压端子与接地点之间;所述子模块级联结构一端连接至器件级联结构S1与S4’之间的连接点,另外一端连接至器件级联结构S1’与S4之间连接点。
进一步地,所述器件级联结构由多个电力电子器件串联组成,所述电力电子器件包括全控型器件(如IGBT,GTO等)及其反并联二极管、半控型器件(如晶闸管等)或者二极管。
进一步地,所述子模块级联结构由多个半桥子模块级联结构与电抗器串联组成、全桥子模块级联结构与电抗器串联组成或全桥子模块级联结构与半桥子模块级联结构混合组成,所述半桥子模块由全控型器件串联后与电容器并联组成;所述全桥子模块由H桥与电容器并联组成;所述H桥的每个桥臂由全控型器件(如IGBT,GTO等)组成;每个全控型器件均反并联二极管。
进一步地,所述装置包括至少两个基本功能模块时,形成两相结构或两相以上结构,即变换单元,所述变换单元的工作频率为基频或高频。
进一步地,在所述器件级联结构开通或关断时,调整子模块级联结构的投入数量,实现器件级联结构的软开关功能。
本发明还提供一种直流电压变换装置的桥臂控制方法,所述直流电压变换装置中的基本功能模块通过桥臂控制实现电压变换;其改进之处在于,所述方法依据基本功能模块的连接方式不同包括下述实现方式:
1)所述基本功能模块包括呈星形连接的两组器件级联结构S1和S4以及子模块级联结构;所述子模块级联结构的一端分别与器件级联结构S1的一端和器件级联结构S4的一端连接;所述器件级联结构S1的另一端连接至低压端子,所述器件级联结构S4的另一端连接至接地 点;所述子模块级联结构的另一端连接至高压端子;当所述器件级联结构S1导通时,器件级联结构S4关断,低压端子正极电流通过器件级联结构S1进入子模块级联结构,所述子模块级联结构输出的电压为高压端电压减低压端电压,用于补偿高压端和低压端的电压差;当器件级联结构S4导通时,器件级联结构S1关断,低压端和高压端的电流差通过器件级联结构S4注入子模块级联结构,子模块级联结构输出的电压为高压端电压,用于补偿高压端对地电压差;
2)基本功能模块包括呈星形连接的两组器件级联结构S1和S4以及子模块级联结构;所述子模块级联结构的一端分别与器件级联结构S1的一端和器件级联结构S4的一端连接;所述器件级联结构S1的另一端连接至高压端子,所述器件级联结构S4的另一端连接至低压端子;所述子模块级联结构的另一端连接至接地点;当所述器件级联结构S1导通时,所述器件级联结构S4关断,高压端正极电流通过器件级联结构S1进入子模块级联结构,所述子模块级联结构输出的电压为高压端电压,用于补偿高压端对地电压差;当所述器件级联结构S4导通时,所述器件级联结构S1关断,低压端电流通过器件级联结构S4注入子模块级联结构,所述子模块级联结构输出的电压为低压端电压,用于补偿低压侧对地电压差;
3)所述基本功能模块包括呈星形连接的四组器件级联结构S1、S4’、S1’和S4以及子模块级联结构;所述器件级联结构S1和S4’连接于高压端子与低压端子之间,另两组器件级联结构S1’和S4连接于低压端子与接地点之间;所述子模块级联结构一端连接至器件级联结构S1与S4’之间的连接点,另外一端连接至器件级联结构S1’与S4之间连接点;当所述器件级联结构S1和S1’导通时,所述器件级联结构S4和S4’关断,高压端正极电流通过器件级联结构S1和S1’进入子模块级联结构,所示子模块级联结构输出的电压为高压端电压减低压端电压,用于补偿高压端和低压端的电压差;当所述器件级联结构S4和S4’导通时,所述器件级联结构S1和S1’关断,低压端和高压端的电流差通过所述器件级联结构S4和S4’注入子模块级联结构,所述子模块级联结构输出的电压为低压端电压,用于补偿低压端对地电压差。
本发明还提供一种直流电压变换装置,其改进之处在于,所述装置包括基本变换单元,由所述基本变换单元组成实现直流电能变换的单极结构或者双极结构。
进一步地,所述基本变换单元由两相或者多相的基本功能模块并联构成;通过桥臂控制方法,实现直流电能的变换。
进一步地,所述基本功能模块包括连接成星形结构的两个器件级联结构和一个子模块级联结构;
其中一个器件级联结构的剩余一端连接至高压端正极端子,另一个器件级联结构的剩余一端连接至接地点;子模块级联结构的剩余一端连接至低压端正极端子。
进一步地,所述基本功能模块通过附加子模块级联结构构成具有多种直流电压变换能力的多直流端子基本功能模块。
进一步地,所述器件级联结构由全控型器件及其反并联的二极管、半桥子模块、全桥子模块结构中的一种单独串联而成,或由其中的几种混合串联而成,或由以上组成的结构串联电感形成;在没有功率反向需求的情况下,省去由全控型器件及其反并联二极管形成的基本功能模块中上桥臂或下桥臂的全控型器件,变为二极管级联或者二极管与电感的串联结构。
进一步地,所述子模块级联结构由多个全桥子模块或半桥子模块级联组成,或由多个全桥 子模块或半桥子模块级联结构串联电感组成。
进一步地,所述全桥子模块由H桥并联电容器组组成,H桥的每个桥臂均由全控器件模块以及与其反并联的二极管组成,所述半桥子模块由单相桥臂并联电容器组组成,所述单相桥臂包括上下两个桥臂,每个桥臂子模块均由全控器件模块以及与其反并联的二极管组成;
所述全控器件模块由单个全控器件,或由全控器件串联或者并联组成,所述电容器组由单个电容器,或由多个电容串联或者并联组成。
本发明还提供一种直流电压变换装置的桥臂控制方法,其改进之处在于,当基本变换单元为单相基本功能模块时,所述桥臂控制方法包括下述步骤:
(1)当基本功能模块的上桥臂导通时,其下桥臂关断,高压端正极电流Id1通过上桥臂进入对应的子模块级联结构,子模块级联结构输出Ud1-Ud2,用于补偿高压侧和低压侧输出端子两端的电压差;
(2)当基本功能模块的下桥臂导通时,其上桥臂关断,基本功能模块的低压端和高压端电流差Id2-Id1通过下桥臂注入子模块级联结构,子模块级联结构输出-Ud2,用于补偿低压侧输出端子对地电压差;
(3)当基本功能模块的上桥臂和下桥臂导通时间相同时,由于子模块级联结构两次充放电功率相等,维持电容器组能量不变,完成直流电能的变换。
进一步地,所述基本功能模块的上桥臂和下桥臂导通时间根据平衡设定方式进行设计,基本功能模块的上桥臂和下桥臂的开关频率设定范围无限制。
进一步地,所述平衡设定方式根据子模块级联结构电压或者能量波动情况,调整相应的基本功能模块的上桥臂和下桥臂开通时间比例。
进一步地,当所述基本功能模块的上桥臂和下桥臂进行开通和关断时,通过调整子模块级联结构的输出使其软开关。
与最接近的现有技术相比,本发明提供的技术方案具有的优异效果是:
1、本发明提供的技术方案可实现宽范围的电压变比。直流电压等级的多样性,要求电压变换器能够实现宽范围的电压变比,能够满足不同场合的要求;
2、具备双向功率流动能力。由于直流电网功率调控的灵活性需求,直流电压变换器需要具备双向功率调节能力;
3、具有好的故障隔离能力。良好的直流变压器应满足在一侧直流故障情况下,另一侧的运行不受到任何影响,即具备故障隔离能力;
4、低的投资、损耗和占地水平。良好的直流变压器应投资少,具备低损耗水平,同时相应的组件不宜过多导致占地过大。
5、本发明提供的直流电压变换装置仅采用IGBT串联结构和一定数量的子模块串联实现电压变换,投资少,损耗小,同时,高频运行对损耗的提升少;良好的直流变压器应投资少,具备低损耗水平;
6、本发明提供的直流电压变换装置两端直流侧电压电流质量高,不需要其他滤波器;
7、本发明提供的直流电压变换装置能够有效实现故障隔离;良好的直流变压器应满足在一侧直流故障情况下,另一侧的运行不受到任何影响,即具备故障隔离能力;
8、本发明提供的直流电压变换装置具有变比范围宽,宽范围的可实现电压变比。直流电压等级的多样性,要求电压变换器能够实现宽范围的电压变比,能够满足不同场合的要求。
9、本发明提供的直流电压变换装置具有功率流动能力,由于直流电网功率调控的灵活性需求,相应的,直流电压变换器需要具备双向功率调节能力。
为了上述以及相关的目的,一个或多个实施例包括后面将详细说明并在权利要求中特别指出的特征。下面的说明以及附图详细说明某些示例性方面,并且其指示的仅仅是各个实施例的原则可以利用的各种方式中的一些方式。其它的益处和新颖性特征将随着下面的详细说明结合附图考虑而变得明显,所公开的实施例是要包括所有这些方面以及它们的等同。
附图说明
附图用来提供对本发明的进一步理解,并且构成说明书的一部分,与本发明的实施例一起用于解释本发明,并不构成对本发明的限制。在附图中:
图1是本发明提供的半桥或全桥子模块结构图,其中(a)为半桥子模块结构;(b)为全桥子模块结构;
图2是本发明提供的基本功能模块结构图,其中(a)为基本功能模块结构图一;(b)为基本功能模块结构图二;(c)为基本功能模块结构图三;
图3是本发明提供的三相变换单元结构图,其中(a)为三相变换单元结构图一;(b)为三相变换单元结构图二;(c)为三相变换单元结构图三。
图4是本发明提供的基本功能模块工作机理图(单直流端子);
图5是本发明提供的基本功能模块工作机理图(多直流端子);
图6是本发明提供的单相变换单元及工作机理图;
图7是本发明提供的多相变换单元拓扑结构图;
图8是本发明提供的直流电压变换装置双极结构图;
图9是本发明提供的三直流端子三相基本变换单元结构图。
具体实施方式
下面结合附图对本发明的具体实施方式作进一步的详细说明。
以下描述和附图充分地示出本发明的具体实施方案,以使本领域的技术人员能够实践它们。其他实施方案可以包括结构的、逻辑的、电气的、过程的以及其他的改变。实施例仅代表可能的变化。除非明确要求,否则单独的组件和功能是可选的,并且操作的顺序可以变化。一些实施方案的部分和特征可以被包括在或替换其他实施方案的部分和特征。本发明的实施方案的范围包括权利要求书的整个范围,以及权利要求书的所有可获得的等同物。在本文中,本发明的这些实施方案可以被单独地或总地用术语“发明”来表示,这仅仅是为了方便,并且如果事实上公开了超过一个的发明,不是要自动地限制该应用的范围为任何单个发明或发明构思。
本发明提供一种直流电压变换装置,所述装置为单相或者多相结构,每相由基本功能模块组成,所述基本功能模块包括串联的器件级联结构和子模块级联结构;主要有三种实现形式:
如图2(a)所示,所述基本功能模块包括呈星形连接的两组器件级联结构S1和S4以及子模块级联结构;所述子模块级联结构的一端分别与器件级联结构S1的一端和器件级联结构 S4的一端连接;所述器件级联结构S1的另一端连接至低压端子(VL),所述器件级联结构S4的另一端连接至接地点;所述子模块级联结构的另一端连接至高压端子(VH)。
如图2(b)所示,所述基本功能模块包括呈星形连接的两组器件级联结构S1和S4以及子模块级联结构;所述子模块级联结构的一端分别与器件级联结构S1的一端和器件级联结构S4的一端连接;所述器件级联结构S1的另一端连接至高压端子(VH),所述器件级联结构S4的另一端连接至低压端子(VL);所述子模块级联结构的另一端连接至接地点。
如图2(c)所示,所述基本功能模块包括呈星形连接的四组器件级联结构S1、S4’、S1’和S4以及子模块级联结构;所述器件级联结构S1和S4’连接于高压端子(VH)与低压端子(VL)之间,另两组器件级联结构S1’和S4连接于低压端子(VL)与接地点之间;所述子模块级联结构一端连接至器件级联结构S1与S4’之间的连接点,另外一端连接至器件级联结构S1’与S4之间连接点。
器件级联结构由多个电力电子器件串联组成,所述电力电子器件包括全控型器件(如IGBT,GTO等)及其反并联二极管、半控型器件(如晶闸管等)或者二极管。
子模块级联结构由多个半桥子模块级联结构与电抗器串联组成或全桥子模块级联结构与电抗器串联组成,所述半桥子模块由全控型器件串联支路与电容器并联组成;所述全桥子模块由H桥与电容器并联组成;所述H桥的每个桥臂由全控型器件组成;每个全控型器件(如IGBT,GTO等)均反并联二极管,半桥或全桥子模块结构图如图1(a)和(b)所示。
基本功能模块可以拓展至两相结构,或者增加相数至三相甚至更多相,三相变换单元结构图如图3(a)、(b)和(c)所示,从而形成变换单元,变换单元又可以形成并联或者双极结构。同时,变换单元的工作频率不限于基频,还可以是高频运行。
本发明的直流变换装置拓扑的另外一种有利特点是,通过在器件级联结构开通或者关断时刻,调整子模块级联结构投入的数量,可以有效实现器件级联结构的软开关。
本发明还提供一种直流电压变换装置的桥臂控制方法,所述直流电压变换装置中的基本功能模块通过桥臂控制实现电压变换;包括:
1、对于图2(a)给出的基本功能模块结构,当所述器件级联结构S1导通时,器件级联结构S4关断,低压端子正极电流通过器件级联结构S1进入子模块级联结构,所述子模块级联结构输出的电压为高压端电压减低压端电压,用于补偿高压端和低压端的电压差;当器件级联结构S4导通时,器件级联结构S1关断,低压端和高压端的电流差通过器件级联结构S4注入子模块级联结构,子模块级联结构输出的电压为负的高压端电压,用于补偿高压端对地电压差。
2、对于图2(b)给出的基本功能模块结构,当所述器件级联结构S1导通时,所述器件级联结构S4关断,高压端正极电流通过器件级联结构S1进入子模块级联结构,所述子模块级联结构输出的电压为高压端电压,用于补偿高压端对地电压差;当所述器件级联结构S4导通时,所述器件级联结构S1关断,低压端电流通过器件级联结构S4注入子模块级联结构,所述子模块级联结构输出的电压为低压端电压,用于补偿低压侧对地电压差。
3、对于图2(c)给出的基本功能模块结构,当所述器件级联结构S1和S1’导通时,所述器件级联结构S4和S4’关断,高压端正极电流通过器件级联结构S1和S1’进入子模块级联结构,所示子模块级联结构输出的电压为高压端电压减低压端电压,用于补偿高压端和低压 端的电压差;当所述器件级联结构S4和S4’导通时,所述器件级联结构S1和S1’关断,低压端和高压端的电流差通过所述器件级联结构S4和S4’注入子模块级联结构,所述子模块级联结构输出的电压为低压端电压,用于补偿低压端对地电压差。
本发明提供的直流电压变换装置仅采用器件串联结构和一定数量的子模块串联实现电压变换,投资少,损耗小,同时,高频运行对损耗的提升少;两端直流侧电压电流质量高,不需要其他滤波器;功率双向流动,同时变比范围宽。
本发明提供一种直流电压变换装置,其结构如下:该装置包括基本变换单元,由所述基本变换单元组成单极结构或者双极结构,实现直流电能的变换。双极结构图如图8所示。
基本变换单元由两相或者多相的基本功能模块并联构成;通过桥臂控制方法,实现直流电能的变换。图4是该装置的基本功能模块,该模块由两个器件级联结构和一个子模块级联结构组成,三者连接成星形结构。一个器件级联结构的其余一端连接至高压端正极端子,另一个器件级联结构的其余一端连接至接地点;子模块级联结构其余一端连接至低压端正极端子。基本功能模块可以通过附加子模块级联结构构成具有多种直流电压变换能力的多直流端子基本功能模块,如图5所示。
器件级联结构一般由多个全控型器件(如IGBT,GTO等)以及与其反并联二极管组成,桥臂上可能串联有电抗,另外一种替代方案是通过多个图1(a)所示半桥或者图1(b)所示的全桥子模块串联来取代全控器件串联,全控器件与半桥、全桥子模块进行混联也是一种可行的方案。子模块级联结构为多个图1(a)所示的半桥子模块或者图1(b)所示的全桥子模块的串联结构,桥臂上可能串联有电抗。
在没有功率反向需求的情况下,器件级联结构的上桥臂或者下桥臂的全控型器件可以省去,仅为二极管级联。
子模块级联结构由多个半桥子模块或者全桥子模块级联而成,可能包含一个串联电感。子模块如图1(b)所示,全控器件符号仅代表功能,其可以由多个全控器件串联或者并联组成,电容符号也仅代表功能,其也可以由多个电容串联或者并联组成。
本发明还提供一种直流电压变换装置的桥臂控制方法,当基本变换单元由单相基本功能模块组成时,工作机理如下:
(1)上桥臂S1a导通时,下桥臂关断,高压端正极电流Id1通过上桥臂进入对应的子模块级联结构,此时子模块级联结构输出Ud1-Ud2,用于补偿高压侧和低压侧输出端子两端的电压差;
(2)当下桥臂S2a导通时,上桥臂关断,低压端和高压端的电流差Id2-Id1通过下桥臂注入子模块级联结构,此时子模块级联结构输出-Ud2,用于补偿低压侧输出端子对地电压差。
(3)当S1a和S2a开通时间差不多时,由于子模块级联结构两次充放电功率接近,可以维持电容能量不变,从而完成电能变换。
对于图6所示的单相结构,S1a、S2b和S2a、S1b一般作为互补对进行工作。
1、S1a和S2b导通时,高压端正极电流Id1通过S1a进入对应的子模块级联结构,该子模块级联结构输出Ud1-Ud2,用于补偿高压侧和低压侧输出端子两端的电压差;低压端和高压端的电流差Id2-Id1通过S2b注入子模块级联结构,此时子模块级联结构输出-Ud2,用于补偿低压侧输出端子对地电压差。
2、S2a和S1b导通时,高压端正极电流Id1通过S2a进入对应的子模块级联结构,该子模块级联结构输出Ud1-Ud2,用于补偿高压侧和低压侧输出端子两端的电压差;低压端和高压端的电流差Id2-Id1通过S1b注入子模块级联结构,此时子模块级联结构输出-Ud2,用于补偿低压侧输出端子对地电压差。
由于两个子模块级联结构对应的充电和放电功率基本相同,因此可以保持能量不变,如果两个子模块级联结构能量由于误差等影响有偏差时,可以通过调节两个互补对的投入时间比例来进行调节。
基本功能模块可以拓展至图6的单相结构,或者增加相数至三相甚至更多相(附图7),从而形成基本变换单元,三直流端子三相基本变换单元结构图如图9所示,基本变换单元又可以通过附图8的形式组成双极结构。同时,变换单元的工作频率不限于基频,还可以是低频和高频运行。
本发明拓扑结果的另外一种有利特点是,通过在器件级联结构开通或者关断时刻,调整子模块级联结构投入的数量,可以有效实现器件级联结构的软开关。
在上述的详细描述中,各种特征一起组合在单个的实施方案中,以简化本公开。不应该将这种公开方法解释为反映了这样的意图,即,所要求保护的主题的实施方案需要清楚地在每个权利要求中所陈述的特征更多的特征。相反,如所附的权利要求书所反映的那样,本发明处于比所公开的单个实施方案的全部特征少的状态。因此,所附的权利要求书特此清楚地被并入详细描述中,其中每项权利要求独自作为本发明单独的优选实施方案。
本领域技术人员还应当理解,结合本文的实施例描述的各种说明性的逻辑框、模块、电路和算法步骤均可以实现成电子硬件、计算机软件或其组合。为了清楚地说明硬件和软件之间的可交换性,上面对各种说明性的部件、框、模块、电路和步骤均围绕其功能进行了一般地描述。至于这种功能是实现成硬件还是实现成软件,取决于特定的应用和对整个***所施加的设计约束条件。熟练的技术人员可以针对每个特定应用,以变通的方式实现所描述的功能,但是,这种实现决策不应解释为背离本公开的保护范围。
上文的描述包括一个或多个实施例的举例。当然,为了描述上述实施例而描述部件或方法的所有可能的结合是不可能的,但是本领域普通技术人员应该认识到,各个实施例可以做进一步的组合和排列。因此,本文中描述的实施例旨在涵盖落入所附权利要求书的保护范围内的所有这样的改变、修改和变型。此外,就说明书或权利要求书中使用的术语“包含”,该词的涵盖方式类似于术语“包括”,就如同“包括,”在权利要求中用作衔接词所解释的那样。此外,使用在权利要求书的说明书中的任何一个术语“或者”是要表示“非排它性的或者”。
最后应当说明的是:以上实施例仅用以说明本发明的技术方案而非对其限制,尽管参照上述实施例对本发明进行了详细的说明,所属领域的普通技术人员依然可以对本发明的具体实施方式进行修改或者等同替换,这些未脱离本发明精神和范围的任何修改或者等同替换,均在申请待批的本发明的权利要求保护范围之内。

Claims (20)

  1. 一种直流电压变换装置,所述装置为单相、两相或两相以上结构,每相由基本功能模块组成,其特征在于,所述基本功能模块包括串联的器件级联结构和子模块级联结构。
  2. 如权利要求1所述的直流电压变换装置,其特征在于,所述基本功能模块包括呈星形连接的两组器件级联结构S1和S4以及子模块级联结构;所述子模块级联结构的一端分别与器件级联结构S1的一端和器件级联结构S4的一端连接;所述器件级联结构S1的另一端连接至低压端子,所述器件级联结构S4的另一端连接至接地点;所述子模块级联结构的另一端连接至高压端子。
  3. 如权利要求1所述的直流电压变换装置,其特征在于,所述基本功能模块包括呈星形连接的两组器件级联结构S1和S4以及子模块级联结构;所述子模块级联结构的一端分别与器件级联结构S1的一端和器件级联结构S4的一端连接;所述器件级联结构S1的另一端连接至高压端子,所述器件级联结构S4的另一端连接至低压端子;所述子模块级联结构的另一端连接至接地点。
  4. 如权利要求1所述的直流电压变换装置,其特征在于,所述基本功能模块包括四组器件级联结构S1、S4’、S1’和S4以及子模块级联结构;所述器件级联结构S1和S4’连接于高压端子与低压端子之间,另两组器件级联结构S1’和S4连接于低压端子与接地点之间;所述子模块级联结构一端连接至器件级联结构S1与S4’之间的连接点,另外一端连接至器件级联结构S1’与S4之间连接点。
  5. 如权利要求1所述的直流电压变换装置,其特征在于,所述器件级联结构由电力电子器件串联组成,所述电力电子器件包括全控型器件及其反并联二极管、半控型器件或者二极管。
  6. 如权利要求1所述的直流电压变换装置,其特征在于,所述子模块级联结构由半桥子模块级联结构与电抗器串联组成、全桥子模块级联结构与电抗器串联组成或全桥子模块级联结构与半桥子模块级联结构混合组成,所述半桥子模块由全控型器件串联后与电容器并联组成;所述全桥子模块由H桥与电容器并联组成;所述H桥的每个桥臂由全控型器件组成;每个全控型器件均反并联二极管。
  7. 如权利要求1所述的直流电压变换装置,其特征在于,所述装置包括至少两个基本功能模块时,形成两相结构或两相以上结构,即变换单元,所述变换单元的工作频率为基频或高频。
  8. 如权利要求1所述的直流电压变换装置,其特征在于,在所述器件级联结构开通或关断时,调整子模块级联结构的投入数量,实现器件级联结构的软开关功能。
  9. 一种如权利要求1-8中任一项所述的直流电压变换装置的桥臂控制方法,所述直流电压变换装置中的基本功能模块通过桥臂控制实现电压变换;其特征在于,所述方法依据基本功能模块的连接方式不同包括下述实现方式:
    1)所述基本功能模块包括呈星形连接的两组器件级联结构S1和S4以及子模块级联结构;所述子模块级联结构的一端分别与器件级联结构S1的一端和器件级联结构S4的一端连接;所述器件级联结构S1的另一端连接至低压端子,所述器件级联结构S4的另一端连接至接地点;所述子模块级联结构的另一端连接至高压端子;当所述器件级联结构S1导通时,器件级联结构S4关断,低压端子正极电流通过器件级联结构S1进入子模块级联结构,所述子模块级联结构输出的电压为高压端电压减低压端电压,用于补偿高压端和低压端的电压差;当器件级联结构S4导通时,器件级联结构S1关断,低压端和高压端的电流差通过器件级联结构S4注入子模块级联结构,子模块级联结构输出的电压为高压端电压,用于补偿高压端对地电压差;
    2)基本功能模块包括呈星形连接的两组器件级联结构S1和S4以及子模块级联结构;所述子模块级联结构的一端分别与器件级联结构S1的一端和器件级联结构S4的一端连接;所述器件级联结构S1的另一端连接至高压端子,所述器件级联结构S4的另一端连接至低压端子;所述子模块级联 结构的另一端连接至接地点;当所述器件级联结构S1导通时,所述器件级联结构S4关断,高压端正极电流通过器件级联结构S1进入子模块级联结构,所述子模块级联结构输出的电压为高压端电压,用于补偿高压端对地电压差;当所述器件级联结构S4导通时,所述器件级联结构S1关断,低压端电流通过器件级联结构S4注入子模块级联结构,所述子模块级联结构输出的电压为低压端电压,用于补偿低压侧对地电压差;
    3)所述基本功能模块包括呈星形连接的四组器件级联结构S1、S4’、S1’和S4以及子模块级联结构;所述器件级联结构S1和S4’连接于高压端子与低压端子之间,另两组器件级联结构S1’和S4连接于低压端子与接地点之间;所述子模块级联结构一端连接至器件级联结构S1与S4’之间的连接点,另外一端连接至器件级联结构S1’与S4之间连接点;当所述器件级联结构S1和S1’导通时,所述器件级联结构S4和S4’关断,高压端正极电流通过器件级联结构S1和S1’进入子模块级联结构,所示子模块级联结构输出的电压为高压端电压减低压端电压,用于补偿高压端和低压端的电压差;当所述器件级联结构S4和S4’导通时,所述器件级联结构S1和S1’关断,低压端和高压端的电流差通过所述器件级联结构S4和S4’注入子模块级联结构,所述子模块级联结构输出的电压为低压端电压,用于补偿低压端对地电压差。
  10. 一种直流电压变换装置,其特征在于,所述装置包括基本变换单元,由所述基本变换单元组成实现直流电能变换的单极结构或者双极结构。
  11. 如权利要求10所述的直流电压变换装置,其特征在于,所述基本变换单元由两相或者多相基本功能模块并联构成;通过桥臂控制方法,实现直流电能的变换。
  12. 如权利要求11所述的直流电压变换装置,其特征在于,所述基本功能模块包括连接成星形结构的两个器件级联结构和一个子模块级联结构;
    其中一个器件级联结构的剩余一端连接至高压端正极端子,另一个器件级联结构的剩余一端连接至接地点;子模块级联结构的剩余一端连接至低压端正极端子。
  13. 如权利要求12所述的直流电压变换装置,其特征在于,所述基本功能模块通过附加子模块级联结构构成具有多种直流电压变换能力的多直流端子基本功能模块。
  14. 如权利要求12所述的直流电压变换装置,其特征在于,所述器件级联结构由全控型器件及其反并联的二极管、半桥子模块、全桥子模块结构中的一种单独串联而成,或由其中的几种混合串联而成,或由以上组成的结构串联电感形成;在没有功率反向需求的情况下,省去由全控型器件及其反并联二极管形成的基本功能模块中上桥臂或下桥臂的全控型器件,变为二极管级联或者二极管与电感的串联结构。
  15. 如权利要求12所述的直流电压变换装置,其特征在于,所述子模块级联结构由多个全桥子模块或半桥子模块级联组成,或由多个全桥子模块或半桥子模块级联结构串联电感组成。
  16. 如权利要求15所述的直流电压变换装置,其特征在于,所述全桥子模块由H桥并联电容器组组成,H桥的每个桥臂均由全控器件模块以及与其反并联的二极管组成,所述半桥子模块由单相桥臂并联电容器组组成,所述单相桥臂包括上下两个桥臂,每个桥臂子模块均由全控器件模块以及与其反并联的二极管组成;
    所述全控器件模块由单个全控器件,或由全控器件串联或者并联组成,所述电容器组由单个电容器,或由多个电容串联或者并联组成。
  17. 一种如权利要求10-16中任一项所述的直流电压变换装置的桥臂控制方法,其特征在于,当基本变换单元为单相基本功能模块时,所述桥臂控制方法包括下述步骤:
    (1)当基本功能模块的上桥臂导通时,其下桥臂关断,高压端正极电流Id1通过上桥臂进入对应的子模块级联结构,子模块级联结构输出Ud1-Ud2,用于补偿高压侧和低压侧输出端子两端的电压 差;
    (2)当基本功能模块的下桥臂导通时,其上桥臂关断,基本功能模块的低压端和高压端电流差Id2-Id1通过下桥臂注入子模块级联结构,子模块级联结构输出-Ud2,用于补偿低压侧输出端子对地电压差;
    (3)当基本功能模块的上桥臂和下桥臂导通时间相同时,由于子模块级联结构两次充放电功率相等,维持电容器组能量不变,完成直流电能的变换。
  18. 如权利要求17所述的桥臂控制方法,其特征在于,所述基本功能模块的上桥臂和下桥臂导通时间根据平衡设定方式进行设计,基本功能模块的上桥臂和下桥臂的开关频率设定范围无限制。
  19. 如权利要求18所述的桥臂控制方法,其特征在于,所述平衡设定方式根据子模块级联结构电压或者能量波动情况,调整相应的基本功能模块的上桥臂和下桥臂开通时间比例。
  20. 如权利要求19所述的桥臂控制方法,其特征在于,当所述基本功能模块的上桥臂和下桥臂进行开通和关断时,通过调整子模块级联结构的输出使其软开关。
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