CN111900884A - Power electronic transformation equipment of direct current distribution network and control method thereof - Google Patents
Power electronic transformation equipment of direct current distribution network and control method thereof Download PDFInfo
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- CN111900884A CN111900884A CN202010669994.1A CN202010669994A CN111900884A CN 111900884 A CN111900884 A CN 111900884A CN 202010669994 A CN202010669994 A CN 202010669994A CN 111900884 A CN111900884 A CN 111900884A
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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
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J5/00—Circuit arrangements for transfer of electric power between ac networks and dc networks
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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
- H02M1/00—Details of apparatus for conversion
- H02M1/12—Arrangements for reducing harmonics from ac input or output
- H02M1/126—Arrangements for reducing harmonics from ac input or output using passive filters
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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
- 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
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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
- 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
- H02M3/305—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 thyratron or thyristor type requiring extinguishing means
- H02M3/315—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 thyratron or thyristor type requiring extinguishing means using semiconductor devices only
- H02M3/3155—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 thyratron or thyristor type requiring extinguishing means using semiconductor devices only with automatic control of the output voltage or current
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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
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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
- H02M7/219—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
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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
- 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
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Direct Current Feeding And Distribution (AREA)
Abstract
The invention discloses a power electronic transformation device of a direct current distribution network and a control method thereof, belonging to the technical field of power electronic transformation, and comprising an input stage, an isolation stage and an output stage which are sequentially connected in series, wherein the input stage consists of a clamping pair on a high-voltage alternating current side, the isolation stage consists of N parallel isolation type DC-DC converters, and the output stage consists of low-voltage side DC-DC modules which are connected in series; the isolated DC-DC converter receives the voltage of a high-voltage direct-current side and converts the voltage to the voltage of a low-voltage direct-current side used by the DC-DC module, the adopted topology can be the same as that of the half-bridge module, normal steady-state operation can be carried out, a basis is provided for subsequent direct-current fault tests, and the quality of output voltage is improved; the demand of an AC/DC power distribution network is met; on one hand, high-quality direct current can be output, and on the other hand, the application environment of an alternating current-direct current hybrid power distribution network can be better adapted; when the novel PET topological structure breaks down on the direct current side, the direct current fault self-clearing is realized.
Description
Technical Field
The invention relates to the technical field of power electronic transformation, in particular to power electronic transformation equipment of a direct-current distribution network and a control method thereof.
Background
With the development of high-power electronic technology, the power electronic transformer PET is receiving more and more attention as a novel voltage conversion and energy transfer electric appliance, and has a wide application prospect. The energy in the power system is converted and controlled by power electronic devices and power electronic conversion technology to replace the traditional power transformer in the power distribution system.
At present, a core topology of a power electronic transformer mostly adopts a double-active full-bridge bidirectional DC-DC converter, and an adopted control method generally comprises the following steps: single phase shift control, double phase shift control, triple phase shift control, PWM plus phase shift control, and asymmetric duty cycle phase shift control. The control method reduces the backflow power to different degrees, but cannot completely eliminate the backflow power, the soft switching range is narrow, the efficiency of the power electronic transformer is low, the control algorithm is complex and difficult to realize, the stability and reliability cannot be completely guaranteed, and the large-scale popularization and application are difficult.
A power electronic transformer for a direct current distribution network is an electric energy conversion device which is based on a power electronic conversion technology, has a high-frequency link and a soft switching technology and can realize direct current transformation, current transformation and electric isolation. The power electronic transformer for the direct-current distribution network has the following characteristics:
1) the intermediate alternating current link adopts a high-frequency transformer to replace a traditional power frequency transformer, so that the volume and the weight of the transformer are reduced;
2) the primary and secondary side voltages and currents are accurate and controllable, and compared with the traditional distribution transformer, the power quality is improved to a great extent;
3) the core topology of the power electronic transformer is a modular structure design, so that the modules are convenient to disassemble and maintain, and different application scenes can be easily and freely combined to adapt to different voltage grade requirements and system capacity requirements;
4) the intelligent power grid can be used for interconnection of different medium and low voltage direct current buses, and the advantages of low pollution, high efficiency, intellectualization and the like provide certain guarantee for construction of the intelligent power grid.
Disclosure of Invention
The invention aims to provide a power electronic transformation device of a direct current distribution network and a control method thereof, which can output high-quality direct current on one hand and can better adapt to the application environment of an alternating current-direct current hybrid distribution network on the other hand; when the novel PET topological structure breaks down on the direct current side, the direct current fault self-clearing is realized so as to solve the problem provided in the background technology.
In order to achieve the purpose, the invention provides the following technical scheme: a power electronic transformation device of a direct current distribution network comprises an input stage, an isolation stage and an output stage which are sequentially connected in series, wherein the input stage is composed of clamping pairs on a high-voltage alternating current side, the isolation stage is composed of N isolation type DC-DC converters which are connected in parallel, and the output stage is composed of low-voltage side DC-DC modules which are connected in series;
the isolated DC-DC converter receives the voltage of the high-voltage direct-current side and converts the voltage to the voltage of the low-voltage direct-current side used by the DC-DC module.
Furthermore, the clamping double sub-module consists of two half-bridge sub-modules and a bipolar transistor Vt0 through two clamping diodes Vdc and one bipolar transistor Vt1, a bipolar transistor Vt2 and a capacitor C1, the source electrode of the bipolar transistor Vt1 is connected in series with the drain electrode of the bipolar transistor Vt2 and is also connected in parallel with a high-voltage A-end interface, the drain electrode of the bipolar transistor Vt1 and the source electrode of the bipolar transistor Vt2 are connected in parallel with the capacitor C1 and the clamping diode Vdc, two ends of the plurality of half-bridge sub-modules are connected to two ends of the drain electrode and the source electrode of the bipolar transistor Vt0, and in an operating state, the middle bipolar transistor Vt0 is always connected to ensure that the two half-bridge sub-modules are connected, and the output.
Further, an inductor L is connected in series between the clamping double-sub and the three-phase line, and the inductor L generates induction current to counteract the current on the three-phase line.
Further, the isolated DC-DC converter comprises a capacitor C1, a first H bridge rectifier, a second H bridge rectifier, a capacitor C2 and a capacitor C3, the first H bridge rectifier and the second H bridge rectifier are coupled through a transformer T, the capacitor C1 is connected to the first H bridge rectifier in parallel, the capacitor C2 and the capacitor C3 are connected to the other end of the second H bridge rectifier in series, the two H bridge rectifiers of the isolated DC-DC converter are matched with the transformer T to reduce the high-voltage direct-current voltage to the low-voltage direct-current voltage, and the isolated DC-DC converter of the middle isolation stage also achieves the electrical isolation function of high-voltage measurement and low-voltage side.
Further, the DC-DC module is connected with the low-voltage side of the isolation type DC-DC converter in parallel.
The invention provides another technology, which comprises a control method of power electronic transformation equipment of a direct current distribution network, and the control method comprises the following steps:
s1: a clamping pair on the high-voltage alternating current side converts high-voltage three-phase alternating current voltage HVAC into high-voltage direct current HVDC, and collects voltage and inductive current on the input stage network side;
s2: the isolation type DC-DC converter of the middle isolation level converts the obtained high-voltage direct current voltage HVDC into LVDC;
s3: collecting the filter inductance current and the output voltage of an isolation stage;
s4: the low-voltage is stabilized and rectified by two H bridges and is matched with a transformer T to reduce the high-voltage direct-current voltage to low-voltage direct-current voltage, and the isolation type DC-DC converter of the middle isolation stage also realizes the electrical isolation function of high-voltage measurement and low-voltage side and inputs the direct-current acquisition quantity to an output stage;
s5: the output voltage is compared with the set comparative voltage through a feedback circuit, and an error voltage signal is generated at the same time, the error voltage signal is input into the PWM module through an internal circuit of the DC-DC module, then the PWM adjusts the duty ratio according to the error voltage, and the constant-voltage and constant-frequency alternating voltage on the load side is obtained through adjustment.
Further, for the low-voltage stage requiring only single-phase alternating current or only direct current in S5, the DC-DC module is replaced by a converter or a direct-current load with corresponding functions.
Compared with the prior art, the invention has the beneficial effects that: the invention provides a power electronic transformation device of a direct current distribution network and a control method thereof, the power electronic transformation device of the direct current distribution network and the control method thereof, an inductor L is connected in series between a clamping bipole and a three-phase line, the inductor L generates induction current to offset the current on the three-phase line, the flexible direct current transmission adopts a thyristor which can be independently controlled to be switched on/off, but not the traditional direct current transmission, so that the flexible direct current transmission can work in a passive commutation state, independently control active power and reactive power, does not need additional reactive power compensation, the direct current voltage in the whole process, the direct current bus voltage can well track the voltage and current waveform of a power grid after the instruction voltage is switched into the reactive power, the current can quickly track the instruction signal, a topology submodule can normally carry out voltage equalization control, the topology can be the same as a half-bridge module, and can normally run in a, the method provides a basis for subsequent direct current fault tests and improves the quality of output voltage; the demand of an AC/DC power distribution network is met; on one hand, high-quality direct current can be output, and on the other hand, the application environment of an alternating current-direct current hybrid power distribution network can be better adapted; when the novel PET topological structure breaks down on the direct current side, the direct current fault self-clearing is realized.
Drawings
FIG. 1 illustrates the principle of the present invention;
FIG. 2 is a topological diagram of a transformation apparatus of the present invention;
fig. 3 is a schematic diagram of the clamping bipin of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1-2, a power electronic transformation device of a direct current distribution network includes an input stage, an isolation stage and an output stage, which are sequentially connected in series, wherein the input stage is composed of a clamping pair on a high voltage side and an alternating current side, the isolation stage is composed of N isolation type DC-DC converters connected in parallel, and the output stage is composed of low voltage side DC-DC modules connected in series.
The isolated DC-DC converter receives the voltage of the high-voltage direct-current side and converts the voltage to the voltage of the low-voltage direct-current side used by the DC-DC module.
The isolated DC-DC converter comprises a capacitor C1, a first H bridge rectifier, a second H bridge rectifier, a capacitor C2 and a capacitor C3, wherein the first H bridge rectifier and the second H bridge rectifier are coupled through a transformer T, the capacitor C1 is connected to the first H bridge rectifier in parallel, the capacitor C2 and the capacitor C3 are connected to the other end of the second H bridge rectifier in series, the two H bridge rectifiers of the isolated DC-DC converter are matched with the transformer T to step down high-voltage direct-current voltage to low-voltage direct-current voltage, and the isolated DC-DC converter of the middle isolation stage also realizes the electrical isolation function of high-voltage measurement and low-voltage side.
The DC-DC module is connected with the low-voltage side of the isolation type DC-DC converter in parallel.
Referring to fig. 3, the clamp pair is composed of two half-bridge sub-modules, which are connected in series via two clamp diodes Vdc and a bipolar transistor Vt0, each half-bridge sub-module is composed of a bipolar transistor Vt1, a bipolar transistor Vt2 and a capacitor C1, a source of the bipolar transistor Vt1 is connected in series with a drain of the bipolar transistor Vt2, and is also connected in parallel with an a-terminal interface of high voltage, a drain of the bipolar transistor Vt1 and a source of the bipolar transistor Vt2 are connected in parallel with the capacitor C1 and the clamp diode Vdc, and two ends of the plurality of half-bridge sub-modules are connected to two ends of the drain and the source of the bipolar transistor Vt0, in an operating state, the middle bipolar transistor Vt0 is always connected, it is ensured that the two half-bridge sub-modules are connected, and the output voltage is twice, i.e. the capacitor is always in the bridge arm, which actually, ensuring no oscillation.
The inductance L is connected in series between the clamping double-sub module and the three-phase line, the inductance L generates induced current to offset current on the three-phase line, the flexible direct current transmission adopts a thyristor which can be independently controlled to be switched on/off, but not in the traditional direct current transmission, so that the flexible direct current transmission can work in a passive current conversion state, active power and reactive power are independently controlled, extra reactive compensation is not needed, direct current voltage in the whole process can well track the voltage of a power grid and the current waveform after the command voltage is put into the reactive power, the current can quickly track the command signal, the topological submodule can normally perform voltage balance control, the adopted topology can be the same as that of the half-bridge module, normal steady-state operation can be performed, and a basis is provided for subsequent direct current fault testing.
The invention provides another technology, which comprises a control method of power electronic transformation equipment of a direct current distribution network, and the control method comprises the following steps:
the method comprises the following steps: a clamping pair on the high-voltage alternating current side converts high-voltage three-phase alternating current voltage HVAC into high-voltage direct current HVDC, and collects voltage and inductive current on the input stage network side;
step two: the isolation type DC-DC converter of the middle isolation level converts the obtained high-voltage direct current voltage HVDC into LVDC;
step three: collecting the filter inductance current and the output voltage of an isolation stage;
step four: the low-voltage is stabilized and rectified by two H bridges and is matched with a transformer T to reduce the high-voltage direct-current voltage to low-voltage direct-current voltage, and the isolation type DC-DC converter of the middle isolation stage also realizes the electrical isolation function of high-voltage measurement and low-voltage side and inputs the direct-current acquisition quantity to an output stage;
step five: the output voltage is compared with the set comparative voltage through a feedback circuit, an error voltage signal is generated at the same time, the error voltage signal is input into a PWM module through an internal circuit of the DC-DC module, then the PWM module adjusts the duty ratio according to the error voltage, the constant-voltage and constant-frequency alternating voltage on the load side is obtained through adjustment, and the DC-DC module is replaced by a converter or a direct current load with a corresponding function when the low-voltage level only needs single-phase alternating current or only needs direct current.
The input stage C-MMC adopts a direct current control mode, and the controller is of a double-ring control structure; the modulation strategy adopts nearest level approximation modulation
Common methods for controlling an isolated-stage DC-DC converter are: the method comprises the steps of duty ratio control and conversion of direct-current voltage obtained by an input stage into high-frequency square waves with the duty ratio of 50% through open-loop control, wherein an output stage DC/AC module adopts a three-phase four-wire inverter structure, a control strategy adopts double closed-loop control, a voltage outer ring adopts proportional resonance, and a current inner ring adopts PI control; the input high-voltage alternating current is modulated into high-voltage direct current through primary change, the high-level direct current is coupled and reduced to low-voltage direct current voltage through a winding of a high-level transformer, a DC/DC module adopts a Buck-Boost circuit, the control mode mainly comprises voltage mode control and current mode control, the current mode control is adopted, the high-voltage alternating current is converted into high-voltage direct current, and the high-voltage direct current is rectified into low-voltage alternating current.
The number of high-frequency transformers is reduced, the power density of PET is improved, and the system cost is reduced; the quality of output voltage is improved; the demand of an AC/DC power distribution network is met; the novel PET topological structure can lead out a common direct current bus, so that on one hand, high-quality direct current can be output, and on the other hand, the novel PET topological structure can better adapt to the application environment of an alternating current-direct current hybrid power distribution network; when the novel PET topological structure has a fault on the direct current side, the direct current fault is self-cleared through locking the input stage.
In summary, the following steps: the invention relates to a power electronic transformation device of a direct current distribution network and a control method thereof, wherein an inductor L is connected in series between a clamping bipole and a three-phase line, the inductor L generates induction current to offset the current on the three-phase line, flexible direct current transmission adopts a thyristor which can be controlled to be switched on/off independently instead of the traditional direct current transmission, the flexible direct current transmission can work in a passive current conversion state, active power and reactive power are independently controlled, extra reactive compensation is not needed, direct current voltage in the whole process can well track the voltage and current waveform of a power grid after instruction voltage is put into reactive power, the current can track instruction signals quickly, the topology submodule can normally perform voltage balance control, the adopted topology can be the same as a half-bridge module, normal steady-state operation can be performed, a basis is provided for subsequent direct current fault testing, and the quality of output voltage is improved; the demand of an AC/DC power distribution network is met; on one hand, high-quality direct current can be output, and on the other hand, the application environment of an alternating current-direct current hybrid power distribution network can be better adapted; when the novel PET topological structure breaks down on the direct current side, the direct current fault self-clearing is realized.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be able to cover the technical solutions and the inventive concepts of the present invention within the technical scope of the present invention.
Claims (7)
1. The power electronic transformation equipment of the direct current distribution network is characterized by comprising an input stage, an isolation stage and an output stage which are sequentially connected in series, wherein the input stage is composed of clamping pairs on a high-voltage alternating current side, the isolation stage is composed of N isolation type DC-DC converters which are connected in parallel, and the output stage is composed of low-voltage side DC-DC modules which are connected in series;
the isolated DC-DC converter receives the voltage of the high-voltage direct-current side and converts the voltage to the voltage of the low-voltage direct-current side used by the DC-DC module.
2. A power electronic transformer device for a dc distribution network as claimed in claim 1, wherein the clamping pair comprises two half-bridge sub-modules, each of which comprises two clamping diodes Vdc and a bipolar transistor Vt0, the half-bridge sub-modules comprise bipolar transistors Vt1, Vt2 and C1, the source of the bipolar transistor Vt1 is connected in series with the drain of the bipolar transistor Vt2 and is also connected in parallel with the high voltage a port, the drain of the bipolar transistor Vt1 and the source of the bipolar transistor Vt2 are connected in parallel with the capacitors C1 and the clamping diodes Vdc, and the plurality of half-bridge sub-modules are connected in parallel with the drain and the source of the bipolar transistor Vt0, and in operation, the middle bipolar transistor Vt0 is connected at all times to ensure that the two half-bridge sub-modules are connected and the output voltage is doubled.
3. A power electronic transformer device for a dc distribution network according to claim 2, characterized in that an inductor L is connected in series between the clamping pair and the three phase line, the inductor L generating an induced current to cancel the current on the three phase line.
4. The power electronic transformation device of the direct current distribution network, as claimed in claim 1, wherein the isolated DC-DC converter includes a capacitor C1, a first H-bridge rectifier, a second H-bridge rectifier, a capacitor C2 and a capacitor C3, the first H-bridge rectifier and the second H-bridge rectifier are coupled through a transformer T, the capacitor C1 is connected in parallel to the first H-bridge rectifier, the capacitor C2 and the capacitor C3 are connected in series to the other end of the second H-bridge rectifier, the two H-bridge rectifiers of the isolated DC-DC converter are used to cooperate with the transformer T to step down the high voltage DC voltage to the low voltage DC voltage, and the isolated DC-DC converter of the middle isolation stage also implements the electrical isolation function between the high voltage side and the low voltage side.
5. The power electronic transformation device of a direct current distribution network of claim 1, wherein the DC-DC module is connected in parallel with the low voltage side of the isolated DC-DC converter.
6. The method for controlling the power electronic transformer equipment of the direct current distribution network according to claim 1, characterized by comprising the following steps:
s1: a clamping pair on the high-voltage alternating current side converts high-voltage three-phase alternating current voltage HVAC into high-voltage direct current HVDC, and collects voltage and inductive current on the input stage network side;
s2: the isolation type DC-DC converter of the middle isolation level converts the obtained high-voltage direct current voltage HVDC into LVDC;
s3: collecting the filter inductance current and the output voltage of an isolation stage;
s4: the low-voltage is stabilized and rectified by two H bridges and is matched with a transformer T to reduce the high-voltage direct-current voltage to low-voltage direct-current voltage, and the isolation type DC-DC converter of the middle isolation stage also realizes the electrical isolation function of high-voltage measurement and low-voltage side and inputs the direct-current acquisition quantity to an output stage;
s5: the output voltage is compared with the set comparative voltage through a feedback circuit, and an error voltage signal is generated at the same time, the error voltage signal is input into the PWM module through an internal circuit of the DC-DC module, then the PWM adjusts the duty ratio according to the error voltage, and the constant-voltage and constant-frequency alternating voltage on the load side is obtained through adjustment.
7. The method for controlling the power electronic transformer equipment of the direct current distribution network, according to claim 6, wherein for the low-voltage stage requiring only single-phase alternating current or only direct current in S5, the DC-DC module is replaced by a converter or a direct current load with corresponding functions.
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112350609A (en) * | 2020-12-07 | 2021-02-09 | 哈尔滨理工大学 | Delta rectifier design related to energy router topological structure |
| CN112615551A (en) * | 2020-12-09 | 2021-04-06 | 国网湖北省电力有限公司电力科学研究院 | MMC type medium voltage power supply quality comprehensive improving system |
| CN113162447A (en) * | 2021-04-26 | 2021-07-23 | 清华大学 | Power electronic transformer based on step-down AC-DC and medium frequency isolated DC-DC |
| CN113904557A (en) * | 2021-09-18 | 2022-01-07 | 苏州万可顶钇电源有限公司 | Automatic compensation device with high reliability and mutual hot backup of double buses and control method |
| EP4216392A1 (en) * | 2022-01-24 | 2023-07-26 | Abb Schweiz Ag | Power conversion system |
| EP4216391A1 (en) * | 2022-01-24 | 2023-07-26 | Abb Schweiz Ag | Power conversion system |
-
2020
- 2020-07-13 CN CN202010669994.1A patent/CN111900884A/en not_active Withdrawn
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112350609A (en) * | 2020-12-07 | 2021-02-09 | 哈尔滨理工大学 | Delta rectifier design related to energy router topological structure |
| CN112615551A (en) * | 2020-12-09 | 2021-04-06 | 国网湖北省电力有限公司电力科学研究院 | MMC type medium voltage power supply quality comprehensive improving system |
| CN113162447A (en) * | 2021-04-26 | 2021-07-23 | 清华大学 | Power electronic transformer based on step-down AC-DC and medium frequency isolated DC-DC |
| CN113904557A (en) * | 2021-09-18 | 2022-01-07 | 苏州万可顶钇电源有限公司 | Automatic compensation device with high reliability and mutual hot backup of double buses and control method |
| CN113904557B (en) * | 2021-09-18 | 2022-09-23 | 苏州万可顶钇电源有限公司 | Automatic compensation device with high reliability and mutual hot backup of double buses and control method |
| EP4216392A1 (en) * | 2022-01-24 | 2023-07-26 | Abb Schweiz Ag | Power conversion system |
| EP4216391A1 (en) * | 2022-01-24 | 2023-07-26 | Abb Schweiz Ag | Power conversion system |
| WO2023138965A1 (en) * | 2022-01-24 | 2023-07-27 | Abb Schweiz Ag | Power conversion system |
| WO2023138915A1 (en) * | 2022-01-24 | 2023-07-27 | Abb Schweiz Ag | Power conversion system |
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