CN116979589A - Starting method and related device for CHB (common bus) branch of flexible interconnection device - Google Patents
Starting method and related device for CHB (common bus) branch of flexible interconnection device Download PDFInfo
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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
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/36—Arrangements for transfer of electric power between ac networks via a high-tension dc link
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
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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
- H02M1/32—Means for protecting converters other than automatic disconnection
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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
- H02M1/36—Means for starting or stopping 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
- H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
- H02M3/33573—Full-bridge at primary side of an isolation transformer
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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
- H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
- H02M3/33576—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements having at least one active switching element at the secondary side of an isolation transformer
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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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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2113/00—Details relating to the application field
- G06F2113/04—Power grid distribution networks
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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
- H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
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Abstract
The application discloses a method for starting a CHB branch of a flexible interconnection device and a related device, wherein the method is applied to the flexible interconnection device formed by a PET branch, a CHB1 branch and a CHB2 branch; firstly, establishing an equivalent model for starting a CHB branch; and then designing a CHB branch starting method based on the equivalent model. The CHB branch starting method provided by the application can start the flexible interconnection device from one alternating current branch of the CHB1 and the CHB2 without configuring a starting strategy for all three alternating current branches; the problem of the orderly start-up of the flexible interconnection device of the novel series-parallel topology medium-voltage distribution network is solved, all components of the flexible interconnection device can be started from the CHB branch, the occurrence of impact current is avoided while reliable start-up is realized, and the safety of the starting process of the flexible interconnection device is ensured.
Description
Technical Field
The application relates to the technical field of medium-voltage distribution networks, in particular to a method for starting a CHB branch of a flexible interconnection device and a related device.
Background
In recent years, with the rapid development of power electronic technology, the flexible direct current technology is better applied to the power transmission field, long-distance large-capacity transmission of clean energy is realized, and development and application demonstration of the flexible direct current technology in the power distribution field are inspired. The flexible interconnection device (also called intelligent soft switch or flexible multi-state switch) of the power distribution network based on the voltage source converter (VSC, voltage source converter) has flexible power flow regulation and control capability, can dynamically regulate the terminal voltage of the feeder line, and is an effective means for solving the problems of power distribution network voltage out-of-limit, high loss and line overload.
The existing flexible interconnection device of the medium-voltage distribution network mainly adopts a back-to-back MMC (modular multilevel converter) topology, and adopts an alternating-current side starting circuit to charge submodule capacitors of MMC converters at all ends respectively, but aiming at the novel flexible interconnection device of the medium-voltage distribution network in a series-parallel topology as shown in fig. 2, the existing starting mode is not applicable, so that a starting method of a CHB branch of the flexible interconnection device needs to be designed.
Disclosure of Invention
The application provides a method and a related device for starting a CHB (common bus) branch of a flexible interconnection device, which are used for solving the problem of orderly starting the flexible interconnection device of a novel series-parallel topology medium-voltage distribution network.
In view of this, the first aspect of the present application provides a method for starting CHB branch of a flexible interconnection device, applied to the flexible interconnection device, where the flexible interconnection device includes: a PET branch, a CHB1 branch and a CHB2 branch; the method comprises the following steps:
establishing an equivalent model of the CHB1 branch starting;
based on the equivalent model, after the CHB1 branch and the CHB2 branch are subjected to series uncontrolled rectification charging to a preset threshold, unlocking a switching tube of the CHB2 branch and continuously charging a direct-current capacitor of the CHB1 branch to the preset threshold;
carrying out parallel uncontrolled rectification charging on the CHB2 branch and the PET branch until all the capacitances of the CHB2 branch and the PET branch reach a preset threshold, simultaneously carrying out open loop control charging on the PET until the capacitance voltage of the PET branch reaches the preset threshold, and presynchronizing a power grid;
starting an intermediate frequency zero sequence voltage control strategy of the CHB1, charging a direct current capacitor to a preset threshold value, starting a fundamental wave control strategy of the CHB1 branch, completing presynchronization of the CHB1 branch, starting an intermediate frequency zero sequence voltage control strategy of the CHB2 branch, charging the direct current capacitor to the preset threshold value, starting the fundamental wave control strategy of the CHB2 branch, and completing presynchronization of the CHB2 branch;
unlocking a primary side H bridge module of the direct current transformer, charging a secondary side H bridge submodule capacitor to a preset threshold value, closing a secondary side load switch of the direct current transformer, and starting each control strategy of the direct current transformer, thereby completing the whole machine starting of the flexible interconnection device.
Optionally, the establishing an equivalent model of CHB1 branch starting specifically includes:
and disconnecting the power grid branch corresponding to the PET and the CHB2, taking the CHB1 branch as a starting branch of the flexible interconnection device, and establishing an equivalent model for starting the CHB1 branch.
Optionally, based on the equivalent model, after the CHB1 branch and the CHB2 branch are charged to a preset threshold by serial uncontrolled rectification, the switching tube of the CHB2 branch is unlocked and the direct current capacitor of the CHB1 branch is continuously charged to the preset threshold, which specifically includes:
s21, controlling an alternating current contactor in the equivalent model to enable a CHB1 branch and a CHB2 branch to be in a series connection relationship, and charging direct current capacitors of the CHB1 branch and the CHB2 branch until the direct current capacitor voltage reaches 90% of an uncontrolled rectification voltage stable value, and executing a step S22;
s22, unlocking a switching tube of the CHB2 branch circuit, and continuously charging a direct-current capacitor of the CHB1 branch circuit until the voltage of the direct-current capacitor reaches 90% of the stable value of the uncontrolled rectification voltage.
Optionally, the parallel uncontrolled rectifying charging is performed on the CHB2 branch and the PET branch until all the capacitances of the CHB2 branch and the PET branch reach a preset threshold, and meanwhile, the charging is performed on the PET open loop control until the capacitance voltage of the PET branch reaches the preset threshold, so as to presynchronize the power grid, which specifically includes:
s31, locking and unlocking a switching tube of a CHB2 branch circuit, enabling the switching tube of a CHB1 branch circuit to be connected in parallel with the CHB2 branch circuit and the PET branch circuit for uncontrolled rectification and charging, and executing a step S32 when all capacitance voltages of the CHB2 branch circuit and the PET branch circuit reach 90% of an uncontrolled rectification voltage stable value;
s32, unlocking the PET side CHB switch tube, setting a modulation signal modulation ratio, simultaneously pre-synchronizing the power grid, and continuously charging until the capacitance voltage of the PET branch reaches 95% of the rated value.
A second aspect of the present application provides a system for activating a CHB branch of a flexible interconnect, the system comprising:
the establishing unit is used for establishing an equivalent model for starting the CHB1 branch;
the first control unit is used for unlocking a switching tube of the CHB2 branch circuit and continuously charging a direct-current capacitor of the CHB1 branch circuit to a preset threshold value after the CHB1 branch circuit and the CHB2 branch circuit are subjected to series uncontrolled rectification charging to the preset threshold value based on the equivalent model;
the second control unit is used for conducting parallel uncontrolled rectification charging on the CHB2 branch and the PET branch until all the capacitances of the CHB2 branch and the PET branch reach a preset threshold, and conducting open-loop control charging on the PET until the capacitance voltage of the PET branch reaches the preset threshold, and presynchronizing the power grid;
the third control unit is used for starting an intermediate frequency zero sequence voltage control strategy of the CHB1, charging a direct current capacitor to a preset threshold value, starting a fundamental wave control strategy of the CHB1 branch, completing the presynchronization of the CHB1 branch, starting an intermediate frequency zero sequence voltage control strategy of the CHB2 branch, charging the direct current capacitor to the preset threshold value, starting the fundamental wave control strategy of the CHB2 branch, and completing the presynchronization of the CHB2 branch;
and the fourth control unit is used for unlocking the primary side H bridge module of the direct-current transformer, charging the secondary side H bridge submodule capacitor to a preset threshold value, closing a secondary side load switch of the direct-current transformer, and starting each control strategy of the direct-current transformer, thereby completing the whole machine starting of the flexible interconnection device.
Optionally, the establishing unit is specifically configured to:
and disconnecting the power grid branch corresponding to the PET and the CHB2, taking the CHB1 branch as a starting branch of the flexible interconnection device, and establishing an equivalent model for starting the CHB1 branch.
Optionally, the first control unit is specifically configured to:
controlling an alternating current contactor in the equivalent model to enable a CHB1 branch and a CHB2 branch to be in a series connection relationship, and charging direct current capacitors of the CHB1 branch and the CHB2 branch until the voltage of the direct current capacitors reaches 90% of the stable value of uncontrolled rectification voltage;
unlocking the switching tube of the CHB2 branch circuit, and continuously charging the direct-current capacitor of the CHB1 branch circuit until the voltage of the direct-current capacitor reaches 90% of the stable value of the uncontrolled rectification voltage.
Optionally, the second control unit is specifically configured to:
locking and unlocking a switching tube of the CHB2 branch circuit, enabling the switching tube of the CHB1 branch circuit to be connected in parallel with the CHB2 branch circuit and the PET branch circuit for uncontrolled rectifying and charging, and enabling all capacitor voltages of the CHB2 branch circuit and the PET branch circuit to reach 90% of an uncontrolled rectifying voltage stable value;
unlocking the PET side CHB switch tube, setting the modulation signal modulation ratio, pre-synchronizing the power grid, and continuously charging until the capacitance voltage of the PET branch reaches 95% of the rated value.
A third aspect of the application provides an activation device for a CHB branch of a flexible interconnect means, the device comprising a processor and a memory:
the memory is used for storing program codes and transmitting the program codes to the processor;
the processor is configured to execute the steps of the method for starting the CHB branch of the flexible interconnection device according to the first aspect according to the instructions in the program code.
A fourth aspect of the present application provides a computer readable storage medium for storing program code for executing the method for starting up the CHB branch of the flexible interconnect means according to the first aspect described above.
From the above technical scheme, the application has the following advantages:
the application provides a method for starting a CHB branch of a flexible interconnection device, which is applied to the flexible interconnection device, and the flexible interconnection device comprises: a PET branch, a CHB1 branch and a CHB2 branch; the method comprises the following steps: establishing an equivalent model of the CHB1 branch starting; based on an equivalent model, after the CHB1 branch and the CHB2 branch are subjected to series uncontrolled rectification charging to a preset threshold, unlocking a switching tube of the CHB2 branch and continuously charging a direct-current capacitor of the CHB1 branch to the preset threshold; carrying out parallel uncontrolled rectification charging on the CHB2 branch and the PET branch until all the capacitances of the CHB2 branch and the PET branch reach a preset threshold, simultaneously carrying out open loop control charging on the PET until the capacitance voltage of the PET branch reaches the preset threshold, and presynchronizing a power grid; starting an intermediate frequency zero sequence voltage control strategy of the CHB1, charging a direct current capacitor to a preset threshold value, starting a fundamental wave control strategy of the CHB1 branch, completing presynchronization of the CHB1 branch, starting an intermediate frequency zero sequence voltage control strategy of the CHB2 branch, charging the direct current capacitor to the preset threshold value, starting the fundamental wave control strategy of the CHB2 branch, and completing presynchronization of the CHB2 branch; unlocking a primary side H bridge module of the direct current transformer, charging a secondary side H bridge submodule capacitor to a preset threshold value, closing a secondary side load switch of the direct current transformer, and starting each control strategy of the direct current transformer, thereby completing the whole machine starting of the flexible interconnection device.
Compared with the prior art, the method solves the problem of orderly starting of the flexible interconnection device of the novel series-parallel topology medium-voltage distribution network, can start all components of the flexible interconnection device from the CHB branch, avoids the occurrence of impact current while realizing reliable starting, and ensures the safety of the starting process of the flexible interconnection device.
Drawings
Fig. 1 is a schematic flow chart of a method for starting a CHB branch of a flexible interconnection device according to an embodiment of the present application;
fig. 2 is a schematic diagram of a novel series-parallel connection type flexible interconnection device for a medium-voltage distribution network according to an embodiment of the present application;
FIG. 3 is a schematic diagram of a CHB bypass initiation equivalent model provided in an embodiment of the present application;
fig. 4 is a schematic structural diagram of a starting system of a CHB branch of a flexible interconnection device according to an embodiment of the present application.
Detailed Description
In order to make the present application better understood by those skilled in the art, the following description will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the accompanying drawings, and it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
Referring to fig. 1, a method for starting a CHB branch of a flexible interconnection device according to an embodiment of the present application is applied to a flexible interconnection device, where the flexible interconnection device includes: as shown in fig. 2, the power electronic components are respectively a PET branch, a CHB1 branch and a CHB2 branch, and the corresponding ac branches are respectively a PET branch, a CHB1 branch and a CHB2 branch. The CHB branch starting method provided by the application can start the flexible interconnection device from one alternating current branch of the CHB1 and the CHB2 without configuring a starting strategy for all three alternating current branches.
The method comprises the following steps:
step 101, establishing an equivalent model for starting the CHB1 branch;
the step 101 specifically includes the following steps S1:
s1, disconnecting a power grid branch corresponding to PET and CHB2, taking the CHB1 branch as a starting branch of a flexible interconnection device, and establishing an equivalent model for starting the CHB1 branch, as shown in FIG. 3; wherein AC1 and AC3 do not act as the primary starting power source during start-up.
102, based on an equivalent model, carrying out series uncontrolled rectification charging on a CHB1 branch and a CHB2 branch to a preset threshold, unlocking a switching tube of the CHB2 branch, and continuously charging a direct current capacitor of the CHB1 branch to the preset threshold;
in one embodiment, step 102 specifically includes steps 1021 and 1022:
step 1021, controlling an alternating current contactor in the equivalent model to enable the CHB1 branch and the CHB2 branch to be in a series connection relationship, and charging direct current capacitors of the CHB1 branch and the CHB2 branch until the direct current capacitor voltage reaches 90% of an uncontrolled rectification voltage stable value, and executing step 1022;
the step 1021 is specifically described as step S2:
and S2, locking all IGBTs, and only closing the alternating current contactors KM2, KM_CHB1 and KM_CHB2. At this time, CHB1 and CBH2 are in series connection, through resonanceThe direct current capacitors of the CHB1 and the CHB2 are charged, and at the moment, the effective values of the charging currents of the CHB1 and the CHB2 are as follows:
（1）
wherein the method comprises the steps ofFor the grid phase voltage effective value, +.>Is resonance inductance>Is resonance capacitance +.>Is the power frequency angular frequency.
When all the sub-module capacitor voltages of CHB1 and CHB2 are charged to 90% of their uncontrolled rectified voltage stable values, step S3 is entered. At this time, the capacitance voltage of the CHB1 and CHB2 submodules is as follows:
（2）
wherein the method comprises the steps ofThe number of CHB sub-modules is cascaded for CHB1, CHB2 branches.
Step 1022, unlocking the switching tube of the CHB2 branch, and continuously charging the direct-current capacitor of the CHB1 branch until the voltage of the direct-current capacitor reaches 90% of the stable value of the uncontrolled rectification voltage.
Step 1022 specifically illustrates the following step S3:
and S3, unlocking the CHB2 switching tube, and opening an open loop of an alternating current port to output 0V alternating current voltage. The CHB1 dc capacitor is further charged until the CHB1 dc capacitor is flushed to 90% of the steady value of the uncontrolled rectified voltage, and step S4 is entered. At this time, the capacitor voltage of the CHB1 submodule is:
（3）
step 103, carrying out parallel uncontrolled rectification charging on the CHB2 branch and the PET branch until all the capacitances of the CHB2 branch and the PET branch reach a preset threshold, simultaneously carrying out open loop control charging on the PET until the capacitance voltage of the PET branch reaches the preset threshold, and presynchronizing a power grid;
in one embodiment, step 103 specifically includes step 1031 and step 1032:
step 1031, locking and unlocking the switching tube of the CHB2 branch circuit to enable the switching tube of the CHB1 branch circuit to be connected in parallel with the CHB2 branch circuit and the PET branch circuit for uncontrolled rectification charging, and executing step 1032 when all capacitor voltages of the CHB2 branch circuit and the PET branch circuit reach 90% of the steady value of uncontrolled rectification voltage;
the step 1031 is specifically described as step S4:
and S4, locking the CHB2 switching tube, unlocking the CHB1 switching tube, and closing the KM_PET. The CHB1 alternating current port is opened to output 0V alternating current voltage, PET is charged through the starting resistor, and CHB2 is further charged. When the capacitor voltages of all the submodules of the PET sides CHB and CHB2 are charged to 90% of the stable value of the uncontrolled rectification voltage, the step S5 is carried out. At this time, the capacitance voltage of the PET and CHB2 submodules is as follows:
（4）
（5）
wherein the method comprises the steps ofThe number of CHB sub-modules is cascaded for the PET limb.
Step 1032, unlock the PET side CHB switch tube, set the modulation signal modulation ratio, pre-synchronize the power network, and continue charging until the capacitance voltage of the PET branch reaches 95% of the rated value.
The step 1032 specifically includes the following steps S5:
s5, unlocking the PET side CHB switch tube, and opening the loop to set the modulation signal modulation ratioAnd is in phase with the AC2 power grid, and charging is continued. Achieve the rated value of the capacitor voltage of the PET submodule>To ensure reliable charging, the modulation ratio requires:
（6）
modulation ratioThe selection of (2) is not too large or too small, the too large causes slow charging, the too small causes the risk of overcharging the module capacitor, and the +.>。
After the charging is completed, the KM2 is disconnected, the PET and the AC1 power grid are presynchronized, the KM1 is closed, the KM_R is closed, the starting resistor is cut off, all control strategies of the PET side CHB are unlocked to reach a steady state, and then the step S6 is carried out.
Step 104, starting an intermediate frequency zero sequence voltage control strategy of the CHB1, charging a direct current capacitor to a preset threshold value, starting a fundamental wave control strategy of the CHB1 branch, completing presynchronization of the CHB1 branch, starting an intermediate frequency zero sequence voltage control strategy of the CHB2 branch, charging the direct current capacitor to the preset threshold value, starting the fundamental wave control strategy of the CHB2 branch, and completing presynchronization of the CHB2 branch;
the step 104 is specifically described as step S6 to step S9:
step S6, generating intermediate frequency zero sequence voltage by PET alternating current portThe intermediate frequency is +.>Is used for the resonance frequency of the (c),satisfy frequency->。
Unlocking the IGBT of the CHB1, starting an intermediate-frequency zero-sequence voltage control strategy of the CHB1, charging the direct-current capacitor to 95% of the rated value, and entering step S7.
And S7, presynchronizing the CHB1 and an AC2 power grid, closing KM2, starting a CHB1 fundamental wave control strategy, gradually increasing a power command value to a rated value, completing the CHB1 starting, and entering a step S8.
And S8, unlocking the IGBT of the CHB2, starting an intermediate-frequency zero-sequence voltage control strategy of the CHB2, charging the direct-current capacitor to 95% of a rated value, and entering step S9.
Step S9, presynchronizing the CHB2 and the AC3 power grid, closing the KM3, starting a CHB2 fundamental wave control strategy, gradually increasing a power command value to a rated value, completing the starting of the CHB2, and entering step S10.
Step 105, unlocking a primary side H bridge module of the direct current transformer, charging a secondary side H bridge submodule capacitor to a preset threshold value, closing a secondary side load switch of the direct current transformer, and starting each control strategy of the direct current transformer, thereby completing the whole machine starting of the flexible interconnection device.
The step 105 specifically includes the following steps S10:
and S10, unlocking a primary side H bridge module of the direct current transformer, slowly increasing the square wave duty ratio of the output voltage of the primary side H bridge to charge the capacitance of a secondary side H bridge submodule to 95% of a rated value, closing a secondary side load switch of the direct current transformer, and starting all control strategies of the direct current transformer, so that the whole machine of the flexible interconnection device is started.
The above is a method for starting the CHB branch of the flexible interconnection device provided in the embodiment of the present application, and the following is a system for starting the CHB branch of the flexible interconnection device provided in the embodiment of the present application.
Referring to fig. 4, a system for starting CHB branch of a flexible interconnection device according to an embodiment of the present application includes:
a building unit 201, configured to build an equivalent model of CHB1 branch startup;
the first control unit 202 is configured to perform series uncontrolled rectification charging on the CHB1 branch and the CHB2 branch to a preset threshold based on an equivalent model, unlock a switching tube of the CHB2 branch, and continuously charge a dc capacitor of the CHB1 branch to the preset threshold;
the second control unit 203 is configured to perform parallel uncontrolled rectification charging on the CHB2 branch and the PET branch until all the capacitances of the CHB2 branch and the PET branch reach a preset threshold, and perform open loop control charging on the PET until the capacitance voltage of the PET branch reaches the preset threshold, so as to presynchronize the power grid;
the third control unit 204 is configured to start the intermediate frequency zero sequence voltage control strategy of the CHB1, charge the dc capacitor to a preset threshold value, start the fundamental wave control strategy of the CHB1 branch, complete the presynchronization of the CHB1 branch, start the intermediate frequency zero sequence voltage control strategy of the CHB2 branch, charge the dc capacitor to the preset threshold value, and start the fundamental wave control strategy of the CHB2 branch, complete the presynchronization of the CHB2 branch;
and the fourth control unit 205 is configured to unlock the primary side H-bridge module of the dc transformer, charge the secondary side H-bridge submodule capacitor to a preset threshold, close a secondary side load switch of the dc transformer, and start each control strategy of the dc transformer, thereby completing the whole machine start of the flexible interconnection device.
Further, in an embodiment of the present application, there is further provided a device for starting a CHB branch of a flexible interconnection apparatus, where the device includes a processor and a memory:
the memory is used for storing program codes and transmitting the program codes to the processor;
the processor is configured to execute the steps of the method for starting the CHB branch of the flexible interconnection device according to the embodiments of the method described above according to the instructions in the program code.
Further, in an embodiment of the present application, a computer readable storage medium is further provided, where the computer readable storage medium is configured to store program code, where the program code is configured to execute the method for starting the CHB branch of the flexible interconnection device according to the foregoing method embodiment.
It will be clear to those skilled in the art that, for convenience and brevity of description, the specific working procedures of the above-described system and unit may refer to the corresponding procedures in the foregoing method embodiments, which are not repeated here.
The terms "first," "second," "third," "fourth," and the like in the description of the application and in the above-described figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the application described herein may be implemented, for example, in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
It should be understood that in the present application, "at least one (item)" means one or more, and "a plurality" means two or more. "and/or" for describing the association relationship of the association object, the representation may have three relationships, for example, "a and/or B" may represent: only a, only B and both a and B are present, wherein a, B may be singular or plural. The character "/" generally indicates that the context-dependent object is an "or" relationship. "at least one of" or the like means any combination of these items, including any combination of single item(s) or plural items(s). For example, at least one (one) of a, b or c may represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", wherein a, b, c may be single or plural.
In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices, and methods may be implemented in other manners. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of the units is merely a logical function division, and there may be additional divisions when actually implemented, e.g., multiple units or components may be combined or integrated into another system, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other form.
The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
In addition, each functional unit in the embodiments of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.
The integrated units, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application may be embodied essentially or in part or all of the technical solution or in part in the form of a software product stored in a storage medium, including instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: u disk, mobile hard disk, read-Only Memory (ROM), random access Memory (Random Access Memory, RAM), magnetic disk or optical disk, etc.
The above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application.
Claims (10)
1. The method for starting the CHB branch of the flexible interconnection device is characterized by being applied to the flexible interconnection device, and the flexible interconnection device comprises the following steps: a PET branch, a CHB1 branch and a CHB2 branch;
the method comprises the following steps:
establishing an equivalent model of the CHB1 branch starting;
based on the equivalent model, after the CHB1 branch and the CHB2 branch are subjected to series uncontrolled rectification charging to a preset threshold, unlocking a switching tube of the CHB2 branch and continuously charging a direct-current capacitor of the CHB1 branch to the preset threshold;
carrying out parallel uncontrolled rectification charging on the CHB2 branch and the PET branch until all the capacitances of the CHB2 branch and the PET branch reach a preset threshold, simultaneously carrying out open loop control charging on the PET until the capacitance voltage of the PET branch reaches the preset threshold, and presynchronizing a power grid;
starting an intermediate frequency zero sequence voltage control strategy of the CHB1, charging a direct current capacitor to a preset threshold value, starting a fundamental wave control strategy of the CHB1 branch, completing presynchronization of the CHB1 branch, starting an intermediate frequency zero sequence voltage control strategy of the CHB2 branch, charging the direct current capacitor to the preset threshold value, starting the fundamental wave control strategy of the CHB2 branch, and completing presynchronization of the CHB2 branch;
unlocking a primary side H bridge module of the direct current transformer, charging a secondary side H bridge submodule capacitor to a preset threshold value, closing a secondary side load switch of the direct current transformer, and starting each control strategy of the direct current transformer, thereby completing the whole machine starting of the flexible interconnection device.
2. The method for starting the CHB branch of the flexible interconnection device according to claim 1, wherein the establishing an equivalent model of the CHB1 branch starting specifically includes:
and disconnecting the power grid branch corresponding to the PET and the CHB2, taking the CHB1 branch as a starting branch of the flexible interconnection device, and establishing an equivalent model for starting the CHB1 branch.
3. The method for starting the CHB branch of the flexible interconnection device according to claim 1, wherein after the series uncontrolled rectification charging is performed on the CHB1 branch and the CHB2 branch to a preset threshold based on the equivalent model, unlocking a switching tube of the CHB2 branch and continuously charging a dc capacitor of the CHB1 branch to the preset threshold, specifically comprising:
s21, controlling an alternating current contactor in the equivalent model to enable a CHB1 branch and a CHB2 branch to be in a series connection relationship, and charging direct current capacitors of the CHB1 branch and the CHB2 branch until the direct current capacitor voltage reaches 90% of an uncontrolled rectification voltage stable value, and executing a step S22;
s22, unlocking a switching tube of the CHB2 branch circuit, and continuously charging a direct-current capacitor of the CHB1 branch circuit until the voltage of the direct-current capacitor reaches 90% of the stable value of the uncontrolled rectification voltage.
4. The method for starting the CHB branch of the flexible interconnection device according to claim 1, wherein the parallel uncontrolled rectifying and charging is performed on the CHB2 branch and the PET branch until all the capacitances of the CHB2 branch and the PET branch reach a preset threshold, and the open loop controlling and charging is performed on the PET until the capacitance voltage of the PET branch reaches the preset threshold, so as to presynchronize the power grid, specifically including:
s31, locking and unlocking a switching tube of a CHB2 branch circuit, enabling the switching tube of a CHB1 branch circuit to be connected in parallel with the CHB2 branch circuit and the PET branch circuit for uncontrolled rectification and charging, and executing a step S32 when all capacitance voltages of the CHB2 branch circuit and the PET branch circuit reach 90% of an uncontrolled rectification voltage stable value;
s32, unlocking the PET side CHB switch tube, setting a modulation signal modulation ratio, simultaneously pre-synchronizing the power grid, and continuously charging until the capacitance voltage of the PET branch reaches 95% of the rated value.
5. A system for activating a CHB branch of a flexible interconnect device, comprising:
the establishing unit is used for establishing an equivalent model for starting the CHB1 branch;
the first control unit is used for unlocking a switching tube of the CHB2 branch circuit and continuously charging a direct-current capacitor of the CHB1 branch circuit to a preset threshold value after the CHB1 branch circuit and the CHB2 branch circuit are subjected to series uncontrolled rectification charging to the preset threshold value based on the equivalent model;
the second control unit is used for conducting parallel uncontrolled rectification charging on the CHB2 branch and the PET branch until all the capacitances of the CHB2 branch and the PET branch reach a preset threshold, and conducting open-loop control charging on the PET until the capacitance voltage of the PET branch reaches the preset threshold, and presynchronizing the power grid;
the third control unit is used for starting an intermediate frequency zero sequence voltage control strategy of the CHB1, charging a direct current capacitor to a preset threshold value, starting a fundamental wave control strategy of the CHB1 branch, completing the presynchronization of the CHB1 branch, starting an intermediate frequency zero sequence voltage control strategy of the CHB2 branch, charging the direct current capacitor to the preset threshold value, starting the fundamental wave control strategy of the CHB2 branch, and completing the presynchronization of the CHB2 branch;
and the fourth control unit is used for unlocking the primary side H bridge module of the direct-current transformer, charging the secondary side H bridge submodule capacitor to a preset threshold value, closing a secondary side load switch of the direct-current transformer, and starting each control strategy of the direct-current transformer, thereby completing the whole machine starting of the flexible interconnection device.
6. The system for starting up a CHB branch of a flexible interconnect device according to claim 5, wherein said establishing unit is adapted to:
and disconnecting the power grid branch corresponding to the PET and the CHB2, taking the CHB1 branch as a starting branch of the flexible interconnection device, and establishing an equivalent model for starting the CHB1 branch.
7. The system for starting up a CHB branch of a flexible interconnect means according to claim 5, wherein said first control unit is in particular adapted to:
controlling an alternating current contactor in the equivalent model to enable a CHB1 branch and a CHB2 branch to be in a series connection relationship, and charging direct current capacitors of the CHB1 branch and the CHB2 branch until the voltage of the direct current capacitors reaches 90% of the stable value of uncontrolled rectification voltage;
unlocking the switching tube of the CHB2 branch circuit, and continuously charging the direct-current capacitor of the CHB1 branch circuit until the voltage of the direct-current capacitor reaches 90% of the stable value of the uncontrolled rectification voltage.
8. The system for starting up a CHB branch of a flexible interconnect means according to claim 5, wherein said second control unit is in particular adapted to:
locking and unlocking a switching tube of the CHB2 branch circuit, enabling the switching tube of the CHB1 branch circuit to be connected in parallel with the CHB2 branch circuit and the PET branch circuit for uncontrolled rectifying and charging, and enabling all capacitor voltages of the CHB2 branch circuit and the PET branch circuit to reach 90% of an uncontrolled rectifying voltage stable value;
unlocking the PET side CHB switch tube, setting the modulation signal modulation ratio, pre-synchronizing the power grid, and continuously charging until the capacitance voltage of the PET branch reaches 95% of the rated value.
9. An activation device for a CHB branch of a flexible interconnect, said device comprising a processor and a memory:
the memory is used for storing program codes and transmitting the program codes to the processor;
the processor is configured to execute the method of starting up the CHB branch of the flexible interconnect means according to any of claims 1-4 according to instructions in the program code.
10. A computer readable storage medium for storing program code for performing the method of starting up the CHB branch of a flexible interconnect means according to any of claims 1-4.
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