CN107134930A - Power electronics distribution transformer and its control method based on MMC - Google Patents
Power electronics distribution transformer and its control method based on MMC Download PDFInfo
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- CN107134930A CN107134930A CN201710525852.6A CN201710525852A CN107134930A CN 107134930 A CN107134930 A CN 107134930A CN 201710525852 A CN201710525852 A CN 201710525852A CN 107134930 A CN107134930 A CN 107134930A
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- mmc
- inverter
- bridge arm
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Classifications
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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
- H02M5/00—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases
- H02M5/40—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc
- H02M5/42—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters
- H02M5/44—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac
- H02M5/453—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal
- H02M5/458—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M5/4585—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only having a rectifier with controlled elements
-
- 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
-
- 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
Abstract
The invention discloses the power electronics distribution transformer based on MMC and its control method, its transformer includes MMC rectifier module, DC DC isolators and the DC AC inverters being sequentially connected, the input of MMC rectifier module is connected with High-voltage AC Network, and the output end of DC AC inverters is connected with low-voltage alternating-current power network；Its method includes step：First, the rectification of High Level AC Voltage；Then, the decompression of the output high-voltage dc voltage of MMC rectifier module；Finally, the inversion of low-voltage dc voltage；The quantity that IGBT of the present invention is used is few, cost is low, reliability is high, extend capacity convenient, three-phase imbalance occurs for High-voltage AC Network or during voltage dip failure, and power electronics distribution transformer long-term safety and can reliably be run, and power supply quality is high, low-voltage alternating-current power network break down the impact to High-voltage AC Network fluctuate small, efficiency high.
Description
Technical field
The invention belongs to electrical equipment technical field, and in particular to a kind of power electronics distribution transformer based on MMC and
Its control method.
Background technology
Due to the energy-saving adjustment for promoting energy resource structure so that the regenerative resource such as wind energy, solar energy is in electric power energy
Role is increasingly weighed in source, and therefore, the requirement for the intellectuality of following power network, flexibility, interactive etc. is also to get over
Come higher.China's power network proposes the target of the development of intelligent grid, and whether the realization of this target will primarily depend upon electricity
The performance and intelligent level of the smart machine used in net.In numerous electrical equipments that current power network is used, distribution transformer
Device is one of mostly important electrical equipment in most widely used, status in power distribution network, and its major function is realized 6kV-
35kV voltages are converted to 380V voltages supply user and used.And the l/3 of China's transformer year production total capacity is distribution transformer
Device.So, the performance indications and intelligent level of distribution transformer will have a strong impact on following China's intelligent grid intellectuality
Level and power supply quality.
Block combiner multi-level converter (Modular Multilevel Convert), abbreviation MMC is a kind of new
Many level topologys, except having the advantages that traditional multi-level rectifier, MMC uses Modular Structure Design, is easy to System Expansion
And redundancy of effort, with fault traversing and recovery capability, system reliability is high.However, the control of the distribution transformer based on MMC
Element is more, and system control is complicated, expensive, and its application is limited to a certain extent.In addition, in power system, three-phase
Imbalance can be divided into uneven two classes of fault uneven and non-faulting.For non-faulting three-phase imbalance, though allow
Long-term existence under operating mode, but as long as transmission line of electricity three-phase imbalance is more than to a certain degree, may result in circuit transmission capacity it is not enough,
The problems such as line loss increase and false protection, harm is produced to power system；Long-term existence can then have a strong impact on power network
Safety, economy, stable operation.
The content of the invention
In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is that being based on there is provided one kind
MMC power electronics distribution transformer and its control method, the quantity that its IGBT is used is few, and cost is low, and reliability is high, and extension is held
Amount is convenient, and when three-phase imbalance or voltage dip failure occur for High-voltage AC Network (4), power electronics distribution transformer can
Safely and reliably run, power supply quality is high, the shock wave that low-voltage alternating-current power network (5) breaks down to High-voltage AC Network (4)
Move small, efficiency high.
In order to solve the above technical problems, the technical solution adopted by the present invention is：Power electronics distribution transformer based on MMC
Device, it is characterised in that：Including the MMC rectifier module being sequentially connected, DC-DC isolators and DC-AC inverter, the MMC is whole
The input of stream device module is connected with High-voltage AC Network, and the output end of the DC-AC inverter is connected with low-voltage alternating-current power network；
The DC-DC isolators include multiple DC-DC and isolate subelement, the voltage input ends of multiple DC-DC isolation subelements according to
Secondary to be connected in series between the DC output end of MMC rectifier module, the output end of multiple DC-DC isolation subelements is in parallel
It is connected between the direct-flow input end of DC-AC inverter；Sub- inverter that DC-DC isolation subelement includes being sequentially connected,
Sub- intermediate-frequency transformer and sub- rectifier, the sub- inverter include by upper bridge arm electric capacity, upper bridge arm IGBT, lower bridge arm electric capacity and under
The single-phase full bridge inverter circuit of bridge arm IGBT compositions, the input parallel connection of the single-phase full bridge inverter circuit is connected to derided capacitors,
The sub- rectifier is that diode does not control bridge rectifier.
The above-mentioned power electronics distribution transformer based on MMC, it is characterised in that：The DC-AC inverter is that three-phase is complete
Bridge inverter, filter inductance is connected between the three-phase full-bridge inverter and the low-voltage alternating-current power network.
The above-mentioned power electronics distribution transformer based on MMC, it is characterised in that：The diode does not control bridge rectifier
Including diode-bridge circuit and the filter capacitor in parallel with the output end of the diode-bridge circuit.
The above-mentioned power electronics distribution transformer based on MMC, it is characterised in that：The MMC rectifier module is three-phase
Include upper bridge arm and lower bridge arm, the upper bridge arm and the lower bridge per phase in six bridge arm circuits, the bridge arm circuit of three-phase six
Arm includes a current-limiting reactor and the M MMC submodules being connected in series, one end of the individual submodules being connected in series of the M
Connect with one end of current-limiting reactor, the other end of the current-limiting reactor connects with the High-voltage AC Network, the series connection
The other end of the MMC submodules of connection connects with the sub- inverter, and the MMC submodules include half-bridge circuit and submodule electricity
Hold, the submodule electric capacity is in parallel with the half-bridge circuit signal output part.
The above-mentioned power electronics distribution transformer based on MMC, it is characterised in that：Half-bridge circuit half-bridge on MMC
Half-bridge IGBT is constituted under IGBT and MMC.
Can in the case where High-voltage AC Network exports three-phase imbalance or voltage dip failure present invention also offers one kind
Operation steady in a long-term, power attenuation is small, efficiency high power electronics distribution transformer control method, it is characterised in that the controlling party
Method comprises the following steps：
Step 1: the rectification of High Level AC Voltage, process is as follows：
The A phase current instantaneous values i of step 101, in real time measurement High-voltage AC NetworkA, A phase voltage instantaneous values uSA, B phase currents
Instantaneous value iB, B phase voltage instantaneous values uSB, C phase current instantaneous values iCWith C phase voltage instantaneous values uSC；
Step 102, according to formulaCalculate High-voltage AC Network
The positive-sequence component i of A phase transient currentsA +, B phase transient currents positive-sequence component iB +With the positive-sequence component i of C phase transient currentsC +；
According to formulaCalculate the A phase currents of High-voltage AC Network
Negative sequence component iA -, B phase currents negative sequence component iB -With the negative sequence component i of C phase currentsC -；
According to formulaCalculate the A of High-voltage AC Network
The positive-sequence component u of phase instantaneous voltageSA +, B phase instantaneous voltages positive-sequence component uSB +With the positive-sequence component u of C phase instantaneous voltagesSC +；Its
In, ω is the angular frequency of High-voltage AC Network voltage；
According to formulaCalculate the A of High-voltage AC Network
The negative sequence component u of phase instantaneous voltageSA -, B phase instantaneous voltages negative sequence component uSB -With the negative sequence component u of C phase instantaneous voltagesSC -；
Step 103, to iA +、iB +And iC +Q axle forward-order currents i can be obtained by carrying out dq conversionq +With d axle forward-order currents id +, to iA -、
iB -And iC -Q axle negative-sequence currents i can be obtained by carrying out dq conversionq -With d axle negative-sequence currents id -；
To uSA +、uSB +And uSC +Q axle positive sequence High-voltage AC Network instantaneous voltages u can be obtained by carrying out dq conversionSq +It is high with d axles positive sequence
Press AC network instantaneous voltage uSd +, to uSA -、uSB -And uSC -Q axle negative phase-sequence High-voltage AC Network instantaneous voltages can be obtained by carrying out dq conversion
uSq -With d axle negative phase-sequence High-voltage AC Network instantaneous voltages uSd -；
Step 104, using the first pi regulator to MMC rectifier module output high-voltage dc voltage be adjusted, obtain d
Axle forward-order current reference valueWherein,uDC *For MMC rectifier mould
Block exports high-voltage dc voltage setting value, uDCHigh-voltage dc voltage real-time measurement values, K are exported for MMC rectifier modulep 1For institute
State the proportionality coefficient of the first pi regulator, Ki 1For the integral coefficient of first pi regulator；
The MMC rectifier module is the bridge arm circuit of three-phase six, per mutually including upper bridge in the bridge arm circuit of three-phase six
Arm and lower bridge arm, the upper bridge arm and the lower bridge arm include a current-limiting reactor and the M MMC submodules being connected in series
Block, the M one end of submodule being connected in series connect with one end of current-limiting reactor, the other end of the current-limiting reactor
Connect with the High-voltage AC Network, the other end of the submodule being connected in series connects with the sub- inverter, the son
Module includes half-bridge circuit and submodule electric capacity, and the submodule electric capacity is in parallel with the half-bridge circuit signal output part；
Step 105, using the second pi regulator to d axle forward-order currents reference value, q axle forward-order currents reference value, d axle negative phase-sequences
Current reference value and q axle negative-sequence current reference values are adjusted, and according to formula
Calculate MMC rectifier module d axle positive sequence input voltages uMd +With MMC rectifier module q axle positive sequence input voltages uMq +, according to formulaCalculate the input of d axle negative phase-sequence MMC rectifiers module
Voltage uMd -With q axle negative phase-sequence MMC rectifier module input voltages uMq -, wherein,Reference value for q axle forward-order currents and Reference value for d axle negative-sequence currents and Reference value for q axle negative-sequence currents andKp 2For
The proportionality coefficient of second pi regulator, Ki 2For the integral coefficient of the second pi regulator, L is the inductance value of the current-limiting reactor；
Step 106, to uMd +And uMq +Carry out dq inverse transformations and obtain MMC rectifier modules A phase positive sequence input voltage uMA +, B phases
Positive sequence input voltage uMB +With C phase positive sequence input voltages uMC +；To uMd -And uMq -Carry out dq inverse transformations and obtain MMC rectifier modules A
Phase negative phase-sequence input voltage uMA -, B phases negative sequence voltage input uMB -With C phase negative phase-sequence input voltages uMC -；According to formulaCalculate MMC rectifier modules A phase input voltage uMA, MMC rectifier module B phases input electricity
Press uMBWith MMC rectifier module C phase input voltages uMC；
Step 107, the quantity for obtaining each bridge arm input MMC submodules of the bridge arm circuit of three-phase six：To the bridge arm circuit of three-phase six
In be determined respectively per the MMC submodule input quantities of phase, and MMC submodules in the bridge arm circuit of three-phase six in any one phase
The determination method all same of input quantity；
When being determined to the MMC submodule input quantities in the bridge arm circuit of three-phase six per phase, process is as follows：
Step I, according to formulaCalculate the input number under every phase on bridge arm in the bridge arm circuit of three-phase six
D1, wherein, ceil () is round up function, uMFor any one phase input voltage, u in MMC rectifier module three-phase voltagemmc
For submodule electric capacity rated voltage；
Step II, according to formula D2=M-D1, calculate the input number D in every phase on bridge arm in the bridge arm circuit of three-phase six2；
The output high-voltage dc voltage real-time measurement values u of step 108, MMC rectifier moduleDCVoltage stabilizing：Pass through MMC submodules
Block capacitance voltage ranking method determines that the submodule that each bridge arm is put into completes the output high-voltage dc voltage to MMC rectifier module
uDCVoltage stabilizing；
Step 109, circulation step 101 to step 108, are surveyed in real time to the output high-voltage dc voltage of MMC rectifier module
Value uDCExported；
Step 2: the decompression of the output high-voltage dc voltage of MMC rectifier module, process is as follows：
Step 201, partial pressure：Isolate output high-voltage dc voltage of the subelement to MMC rectifier module using multiple DC-DC
Partial pressure is carried out, the output high pressure of the derided capacitors in sub- inverter and the bridge arm electric capacity to MMC rectifier module is utilized
DC voltage carries out two-stage partial pressure, obtains partial pressure DC voltage uFC；
Step 202, inversion：50% couple of partial pressure DC voltage u is respectively turned on using two IGBT in sub- inverterFCCarry out
Inversion, obtains square wave alternating voltage；
Step 203, decompression：Sub- intermediate-frequency transformer other side alternating current wave pressure progress, which is depressured, obtains low pressure square wave alternating voltage；
Step 204, rectification and filtering：Sub- rectifier carries out rectification to the low pressure square wave alternating voltage and obtains low-voltage direct
Voltage, and denoising is filtered to low-voltage dc voltage；
Step 3: the inversion of low-voltage dc voltage, process is as follows：
Step 301, using DC-AC inverter to low-voltage dc voltage carry out inversion, while measure DC-AC inverter output
Side A phase instantaneous voltages uva, B phase instantaneous voltages uvbWith C phase instantaneous voltages uvc；
The DC-AC inverter is three-phase full-bridge inverter, the three-phase full-bridge inverter and the low-voltage alternating-current power network
Between be connected with filter inductance；
Step 302, to A phase instantaneous voltages uva, B phase instantaneous voltages uvbWith C phase instantaneous voltages uvcDq conversion is carried out to obtain
DC-AC inverter d axle output voltages uvdWith DC-AC inverter q axle output voltages uvq；
Step 303, using the 3rd pi regulator to DC-AC inverter d axle output voltages uvdIt is defeated with DC-AC inverter q axles
Go out voltage uvqIt is adjusted, obtains DC-AC inverter d axle output voltage adjusted values uvd' and DC-AC inverter q axle output voltages
Adjusted value uvq', wherein,uvd *For DC-AC inverter d axle output voltages
Set reference value, uvq* reference value, K are set for DC-AC inverter q axles output voltagep 3For the proportionality coefficient of the 3rd pi regulator,
Ki 3For the integral coefficient of the 3rd pi regulator；
Step 304, to uvd' and uvq' dq inverse transformations are carried out, obtain three phase sine modulating wave；
Step 305, to the three phase sine modulating wave carry out Frequency conversion control, obtain in three-phase full-bridge inverting circuit
Trigger pulse, IGBT in three-phase full-bridge inverter is controlled according to the trigger pulse, exports symmetrical three phase sine alternating voltage；
Step 306, circulation step 301 to step 305, realize the inversion of low-voltage dc voltage.
The present invention has advantages below compared with prior art：
1st, the power electronics distribution transformer that the present invention is used is by setting DC-DC isolators to reduce the number that IGBT is used
Amount, simplifies the structure of power electronics distribution transformer, reduces the cost of power electronics distribution transformer, improves electric power electricity
The reliability of sub- distribution transformer.
2nd, the equalizing capacitance and bridge arm electric capacity that the power electronics distribution transformer that the present invention is used is set are to MMC rectifier mould
The high-voltage dc voltage of block output carries out step pressure reducing, simple in construction, reasonable in design, and extension capacity is convenient.
3rd, the control method that uses of the present invention by by the reference value of q axle forward-order currents forWith the ginseng of q axle negative-sequence currents
Examine valueIt is disposed as 0 so that power electronics distribution transformer is in the case where rated capacity is constant, it is possible to achieve specific work
Rate factor is controlled, and the active power of power electronics distribution transformer transmission is improved, and reduces power electronics distribution transformer
Loss.
4th, the control method that uses of the present invention carries out the control based on phase component method to MMC rectifier module, by by d axles
The reference value of negative-sequence currentWith the reference value of q axle negative-sequence currentsIt is disposed as 0, it is suppressed that High-voltage AC Network is input to
The negative sequence component of MMC rectifier module input mouthful so that MMC rectifier module can stablize output high-voltage dc voltage, enter
And make it that, when three-phase imbalance or voltage dip failure occur for High-voltage AC Network, power electronics distribution transformer can be grown
Phase is safely and reliably run, and improves power supply quality.
5th, the control method that the present invention is used is by setting DC-DC isolators and having carried out electricity to MMC rectifier module
Flow closed-loop control so that the isolation between High-voltage AC Network and low-voltage alternating-current power network is high, and low-voltage alternating-current power network breaks down
Impact fluctuation to High-voltage AC Network is small.
6th, the control method that the present invention is used improves voltage by carrying out Frequency conversion control to DC-AC inverter
Utilization rate, and then the efficiency high of power electronics distribution transformer.
In summary, the quantity that IGBT of the present invention is used is few, and cost is low, and reliability is high, and extension capacity is convenient, high-voltage alternating
Three-phase imbalance occurs for power network or during voltage dip failure, and power electronics distribution transformer long-term safety and can be transported reliably
OK, power supply quality is high, and small, efficiency high is fluctuated in the impact to High-voltage AC Network of breaking down of low-voltage alternating-current power network.
Below by drawings and examples, technical scheme is described in further detail.
Brief description of the drawings
Fig. 1 is the circuit theory diagrams of power electronics distribution transformer of the present invention.
Fig. 2 is the circuit theory diagrams of DC-DC transformers in power electronics distribution transformer of the present invention.
Fig. 3 is the circuit theory diagrams of half-bridge circuit in power electronics distribution transformer of the present invention.
Fig. 4 is the FB(flow block) of control method of the present invention.
Description of reference numerals:
1-MMC rectifier module；2-DC-DC isolators；3-DC-AC inverter；
1-1-half-bridge circuit；1-2-MMC submodule electric capacity；2-1-sub- inverter；
2-2-sub- intermediate-frequency transformer；2-3-sub- rectifier, 4-High-voltage AC Network；
5-low-voltage alternating-current power network.
Embodiment
As depicted in figs. 1 and 2, including the MMC rectifier module 1, DC-DC isolators 2 and the DC-AC inverter that are sequentially connected
3, the input of the MMC rectifier module 1 is connected with High-voltage AC Network 4, the output end of the DC-AC inverter 3 with it is low
Pressure AC network 5 is connected；The DC-DC isolators 2 include multiple DC-DC and isolate subelement, multiple DC-DC separaants lists
The voltage input end of member is sequentially connected in series between the DC output end of MMC rectifier module 1, multiple DC-DC isolation
The output end of subelement is connected in parallel between the direct-flow input end of DC-AC inverter 3；The DC-DC isolation subelement includes
Sub- inverter 2-1, sub- intermediate-frequency transformer 2-2 and the sub- rectifier 2-3 being sequentially connected, the sub- inverter 2-1 are included by Shang Qiao
The single-phase full bridge inverter circuit that arm electric capacity, upper bridge arm IGBT, lower bridge arm electric capacity and lower bridge arm IGBT are constituted, the single-phase full bridge is inverse
The input parallel connection for becoming circuit is connected to derided capacitors, and the sub- rectifier 2-3 is that diode does not control bridge rectifier.
It should be noted that the setting of the MMC rectifier module 1 is in order to by the ac high-voltage of High-voltage AC Network 4
High direct voltage is converted to, the MMC rectifier module 1 has the advantages that output voltage quality height, efficiency high；The DC-DC every
Setting from device 2 is that, in order to which the high direct voltage is converted into DC low-voltage, DC-DC isolators 2 effectively reduce IGBT's
Usage quantity, reduces the cost of power electronics distribution transformer, and because the IGBT quantity for needing to control is few, and then reduce
The difficulty of the control of DC-DC isolators 2, improves the reliability of DC-DC isolators 2；Multiple DC-DC isolation subelements are used
The frame mode of series connection input Parallel opertation effectively simplifies the control difficulty of DC-DC isolators 2, improves power electronics distribution
Transformer reliability；The setting of DC-AC inverter 3 be in order to by the DC low-voltage inversion be AC low-tension, DC-AC inverter
3 controls are simple, efficiency high；The setting of derided capacitors and the bridge arm electric capacity in order to carry out partial pressure step by step to the high direct voltage,
It is easy to realize, simple in construction；The sub- inverter 2-1, sub- intermediate-frequency transformer 2-2 and sub- rectifier 2-3 are corresponded；It is described
Sub- inverter 2-1 setting is in order to which the high direct voltage inversion for exporting MMC rectifier module 1 is square-wave voltage, sub- inverter
The full-bridge circuit structure that 2-1 is made up of two groups of bridge arm electric capacity and IGBT, with the full-bridge circuit structure phase being made up of four IGBT
Than, the IGBT quantity that sub- inverter 2-1 is used is few, and cost is low, wherein, C1、C2……CNFor the equal derided capacitors of capacitance, C21、
C31、C22、C32……C2N、C3NFor the equal bridge arm electric capacity of capacitance；The sub- rectifier 2-3 is that diode does not control bridge rectifier
Device, simple in construction, cost is low, reduces the difficulty of power electronics distribution transformer control.In the present embodiment, the high-voltage alternating
The output voltage of power network 4 is 10KV, and frequency is 50Hz, and the output voltage of low-voltage alternating-current power network 5 is 380V, and frequency is 50Hz, DC-DC
The quantity for isolating subelement is 10, and sub- intermediate-frequency transformer 2-2 frequency is 5KHz, sub- intermediate-frequency transformer 2-2 primary side winding
No-load voltage ratio with vice-side winding is 1500:1000, sub- intermediate-frequency transformer 2-2 have the advantages that small volume, metal material usage amount are few.
The DC-AC inverter 3 is three-phase full-bridge inverter, the three-phase full-bridge inverter and the low-voltage alternating-current power network
Filter inductance is connected between 5.
As shown in figure 1, in the present embodiment, three-phase full-bridge inverter is by six IGBT groups of S3, S4, S5, S6, S7 and S8
Into being connected with filter inductance L7, L8 and L9, the filtering between the three-phase full-bridge inverter and the low-voltage alternating-current power network 5
The setting of inductance improves the quality of the output voltage of DC-AC inverter 3.
The diode do not control bridge rectifier including diode-bridge circuit and with the diode-bridge circuit simultaneously
The filter capacitor of connection, the two ends of the filter capacitor isolate the low-pressure side of subelement for the DC-DC.
As shown in Fig. 2 in the present embodiment, the bridge-type electricity that sub- rectifier 2-3 is constituted including being connected two-by-two by four diodes
Road, the two ends of the bridge circuit are connected in parallel with the filter capacitor, and the diode is not controlled bridge rectifier and will can handed over
Stream voltage commutation is DC voltage, without individually being controlled, it is easy to accomplish, reliability is high.
The MMC rectifier module 1 is the bridge arm circuit of three-phase six, per mutually including upper bridge in the bridge arm circuit of three-phase six
Arm and lower bridge arm, the upper bridge arm and the lower bridge arm include a current-limiting reactor and the M MMC submodules being connected in series
Block, the M one end of submodule being connected in series connect with one end of current-limiting reactor, the other end of the current-limiting reactor
Connect with the High-voltage AC Network, the other end of the MMC submodules being connected in series connects with the sub- inverter 2-1,
The MMC submodules include half-bridge circuit 1-1 and submodule electric capacity 1-2, the submodule electric capacity 1-2 and the half-bridge circuit 1-
1 signal output part is in parallel.
As shown in figure 1, A phases bridge arm includes in A phases under bridge arm and A phases in bridge arm, A phases bridge arm by MMC submodules SMp1a、
MMC submodules SMp2a... MMC submodules SMpMaIt is connected in series, bridge arm is by MMC submodules SM under A phasesn1a, MMC submodules
SMn2a... MMC submodules SMnMaIt is connected in series；B phases bridge arm include in B phases under bridge arm and B phases in bridge arm, B phases bridge arm by
MMC submodules SMp1b, MMC submodules SMp2b... MMC submodules SMpMbIt is connected in series, bridge arm is by MMC submodules under B phases
SMn1b, MMC submodules SMn2b... MMC submodules SMnMbIt is connected in series；C phases bridge arm includes bridge under bridge arm in C phases and C phases
Bridge arm is by MMC submodules SM in arm, C phasesp1c, MMC submodules SMp2c... MMC submodules SMpMcIt is connected in series, under C phases
Bridge arm is by MMC submodules SMn1c, MMC submodules SMn2c... MMC submodules SMnMcIt is connected in series；The MMC submodules
SMp1a, MMC submodules SMp1bWith MMC submodules SMp1cConnection end and the MMC submodules SMnMa, MMC submodules SMnMbWith
MMC submodules SMnMcConnection end between voltage be MMC rectifier module 1 output high-voltage dc voltage；MMC submodules are adopted
With the mode being connected in series so that expand capacity convenient, fast；Connect in the A phases between bridge arm and the High-voltage AC Network 4
It is connected in current-limiting reactor L1, B phase and current-limiting reactor L2 is connected between bridge arm and the High-voltage AC Network 4, in the C phase
Current-limiting reactor L3 is connected between bridge arm and the High-voltage AC Network 4；Bridge arm and the High-voltage AC Network under the A phases
It is connected between 4 under current-limiting reactor L4, the B phases and is connected with current-limiting reactor between bridge arm and the High-voltage AC Network 4
Current-limiting reactor L6 is connected between bridge arm and the High-voltage AC Network 4 under L5, the C phases；The current-limiting reactor is set
It is impact in order to reduce the DC output end of MMC rectifier module 1 in the case of failure to MMC submodules to put, and improves electric power
The reliability of electrical power distribution transformer；As shown in figure 3, the MMC submodules include half-bridge circuit 1-1 and MMC submodule electric capacity
1-2, the half-bridge circuit 1-1 are in parallel with the MMC submodules electric capacity 1-2.In the present embodiment, each bridge arm of MMC rectifier module 1
The MMC submodules number being connected in series is 12, and the capacitance of multiple MMC submodules electric capacity is 0.018F, multiple described
The rated voltage of MMC submodule electric capacity is 2500V, and the capacitance of multiple derided capacitors is 0.012F, multiple bridges
The capacitance of arm electric capacity is 0.006F, and the inductance value of multiple current-limiting reactors is 0.005mH.
The half-bridge circuit 1-1 is made up of two groups of IGBT and fly-wheel diode, and IGBT described in two groups and fly-wheel diode connect
It is connected into half-H-bridge structure.
As shown in figure 3, half-bridge circuit 1-1 is made up of two groups of IGBT and fly-wheel diode, IGBT described in two groups and afterflow two
Pole pipe connects into half-H-bridge structure.
As shown in figure 4, the control method of power electronics distribution transformer of the present invention, it is characterised in that the controlling party
Method comprises the following steps：
Step 101, in real time measurement High-voltage AC Network 4A phase current instantaneous values iA, A phase voltage instantaneous values uSA, B phase currents
Instantaneous value iB, B phase voltage instantaneous values uSB, C phase current instantaneous values iCWith C phase voltage instantaneous values uSC；
Step 102, according to formulaCalculate High-voltage AC Network 4
A phase transient currents positive-sequence component iA +, B phase transient currents positive-sequence component iB +With the positive-sequence component i of C phase transient currentsC +；
According to formulaCalculate the A phase currents of High-voltage AC Network 4
Negative sequence component iA -, B phase currents negative sequence component iB -With the negative sequence component i of C phase currentsC -；
According to formulaCalculate the A of High-voltage AC Network 4
The positive-sequence component u of phase instantaneous voltageSA +, B phase instantaneous voltages positive-sequence component uSB +With the positive-sequence component u of C phase instantaneous voltagesSC +；Its
In, ω is the angular frequency of the voltage of High-voltage AC Network 4；
According to formulaCalculate the A of High-voltage AC Network 4
The negative sequence component u of phase instantaneous voltageSA -, B phase instantaneous voltages negative sequence component uSB -With the negative sequence component u of C phase instantaneous voltagesSC -；
Step 103, to iA +、iB +And iC +Q axle forward-order currents i can be obtained by carrying out dq conversionq +With d axle forward-order currents id +, to iA -、
iB -And iC -Q axle negative-sequence currents i can be obtained by carrying out dq conversionq -With d axle negative-sequence currents id -；
To uSA +、uSB +And uSC +Q axle positive sequence High-voltage AC Network instantaneous voltages u can be obtained by carrying out dq conversionSq +It is high with d axles positive sequence
Press AC network instantaneous voltage uSd +, to uSA -、uSB -And uSC -Q axle negative phase-sequence High-voltage AC Network instantaneous voltages can be obtained by carrying out dq conversion
uSq -With d axle negative phase-sequence High-voltage AC Network instantaneous voltages uSd -；
It should be noted that, the instantaneous value of the three-phase current exported to High-voltage AC Network 4 carries out symmetrical separation and Extraction electric current
Positive and negative order components method, amplitude and phase without individually calculating three-phase current, method is simple and convenient；The uSA +、uSB +
And uSC +According to formulaCarry out dq conversion and obtain uSq +And uSd +, the uSA -、uSB -And uSC -According to formulaCarry out dq conversion
Obtain uSq -And uSd -；In the present embodiment, the angular frequency of High-voltage AC Network 4 is 314；
Step 104, using the first pi regulator to MMC rectifier module output high-voltage dc voltage be adjusted, obtain d
Axle forward-order current reference valueWherein,uDC *For MMC rectifier mould
Block exports high-voltage dc voltage setting value, uDCHigh-voltage dc voltage real-time measurement values, K are exported for MMC rectifier modulep 1For institute
State the proportionality coefficient of the first pi regulator, Ki 1For the integral coefficient of first pi regulator；
The MMC rectifier module 1 is the bridge arm circuit of three-phase six, per mutually including upper bridge in the bridge arm circuit of three-phase six
Arm and lower bridge arm, the upper bridge arm and the lower bridge arm include a current-limiting reactor and the M MMC submodules being connected in series
Block, the M one end of submodule being connected in series connect with one end of current-limiting reactor, the other end of the current-limiting reactor
Connect with the High-voltage AC Network, the other end of the submodule being connected in series connects with the sub- inverter 2-1, described
Submodule includes half-bridge circuit 1-1 and submodule electric capacity 1-2, the submodule electric capacity 1-2 and the half-bridge circuit 1-1 signals are defeated
Go out end in parallel；
Step 105, using the second pi regulator to d axle forward-order currents reference value, q axle forward-order currents reference value, d axle negative phase-sequences
Current reference value and q axle negative-sequence current reference values are adjusted, and according to formula
Calculate MMC rectifier module d axle positive sequence input voltages uMd +With MMC rectifier module q axle positive sequence input voltages uMq +, according to formulaCalculate the input of d axle negative phase-sequence MMC rectifiers module
Voltage uMd -With q axle negative phase-sequence MMC rectifier module input voltages uMq -, wherein,Reference value for q axle forward-order currents and Reference value for d axle negative-sequence currents and Reference value for q axle negative-sequence currents andKp 2For
The proportionality coefficient of second pi regulator, Ki 2For the integral coefficient of the second pi regulator, L is the inductance value of the current-limiting reactor；
It should be noted that by the reference value of q axle forward-order currentsWith the reference value of q axle negative-sequence currentsIt is disposed as 0
Be in order to MMC rectifier module 1 carry out unity power factor control so that power electronics distribution transformer in rated capacity not
In the case of change, the active power of transformer transmission is improved, and reduces the loss of power electronics distribution transformer；By inciting somebody to action
The reference value of d axle negative-sequence currents isWith the reference value of q axle negative-sequence currentsBeing disposed as 0 realizes to MMC rectifier mould
Block 1 carries out the control based on phase component method, it is suppressed that the High-voltage AC Network 4 is input to the input port of MMC rectifier module 1
Negative sequence component so that MMC rectifier module 1 can stablize output high-voltage dc voltage, and then cause in the high-voltage alternating
When three-phase imbalance or voltage dip failure occur for power network 4, power electronics distribution transformer can safely and reliably be run,
Improve power supply quality；In the present embodiment, L is 0.005mH；
Step 106, to uMd +And uMq +Carry out dq inverse transformations and obtain MMC rectifier modules A phase positive sequence input voltage uMA +, B phases
Positive sequence input voltage uMB +With C phase positive sequence input voltages uMC +；To uMd -And uMq -Carry out dq inverse transformations and obtain MMC rectifier modules A
Phase negative phase-sequence input voltage uMA -, B phases negative sequence voltage input uMB -With C phase negative phase-sequence input voltages uMC -；According to formulaCalculate MMC rectifier modules A phase input voltage uMA, MMC rectifier module B phases input electricity
Press uMBWith MMC rectifier module C phase input voltages uMC；
It should be noted that according to formulaTo uMd +And uMq +Carry out dq contravariant
Get u in returnMA +、uMB +And uMC +, according to formulaTo uMd -With
uMq -Carry out dq inverse transformations and obtain uMA -、uMB -And uMC -, further according to formulaTry to achieve uMA、uMBWith
uMC, wherein, uMAFor MMC submodules SMpMaWith the voltage at current-limiting reactor L1 connection end points, uMBFor MMC submodules SMpMbWith
Voltage at current-limiting reactor L2 connection end points, uMCFor MMC submodules SMpMcWith the voltage at current-limiting reactor L3 connection end points；
Step 107, the quantity for obtaining each bridge arm input MMC submodules of the bridge arm circuit of three-phase six：To the bridge arm circuit of three-phase six
In be determined respectively per the MMC submodule input quantities of phase, and MMC submodules in the bridge arm circuit of three-phase six in any one phase
The determination method all same of input quantity；
When being determined to the MMC submodule input quantities in the bridge arm circuit of three-phase six per phase, process is as follows：
Step I, according to formulaCalculate the input number under every phase on bridge arm in the bridge arm circuit of three-phase six
D1, wherein, ceil () is round up function, uMTo be any one mutually defeated in the input port three-phase voltage of MMC rectifier module 1
Inbound port voltage, ummcFor submodule electric capacity rated voltage；
Step II, according to formula D2=M-D1, calculate the input number D in every phase on bridge arm in the bridge arm circuit of three-phase six2；
The output high-voltage dc voltage real-time measurement values u of step 108, MMC rectifier module 1DCVoltage stabilizing：Pass through submodule
Capacitance voltage ranking method determines that the submodule that each bridge arm is put into completes the output high-voltage dc voltage to MMC rectifier module 1
uDCVoltage stabilizing；
It should be noted that in the present embodiment, bridge arm is according to formula under A phasesCalculating obtains lower bridge arm
The MMC submodule numbers for needing input are D1AIt is individual, according to D2A=M-D1A, it is 12- to calculate the input number obtained in A phases on bridge arm
D1AIt is individual, the rated value u of MMC submodule electric capacitymmcFor 2500V；The side that the MMC submodule input quantities of B phases and C phases are determined
Method is identical with A phases, will not be repeated here；
Step 109, circulation step 101 to step 108, are surveyed in real time to the output high-voltage dc voltage of MMC rectifier module 1
Value uDCExported；
It should be noted that in the present embodiment, the use MMC submodule capacitor voltages ranking method process of A phase bridge arms
It is as follows：First, bridge arm current i in A phases in measurement MMC rectifier module 1 in real timeapWith lower bridge arm current ian, and measure in real time
Each MMC submodules in the size and lower bridge arm of each MMC submodules electric capacity both end voltage in the upper bridge arm of A phases in MMC rectifier module 1
The size of block electric capacity both end voltage；Then, if ian>0, then bridge arm chooses MMC submodule electric capacity both end voltage minimum under A phases
D1AIndividual MMC submodules come into operation, if ian<0, then bridge arm chooses the maximum D of MMC submodule electric capacity both end voltage under A phases1A
Individual MMC submodules come into operation；Finally, if iap>0, then bridge arm chooses MMC submodule electric capacity both end voltage minimum in A phases
12-D1AIndividual MMC submodules come into operation, if iap<0, then bridge arm chooses MMC submodule electric capacity both end voltage maximum in A phases
12-D1AIndividual MMC submodules come into operation；By that analogy, the B phases bridge arm and C phases bridge arm use MMC submodule capacitor voltages
Ranking method determines that the MMC submodules used will be put into, will not be repeated here；The MMC submodule capacitor voltages ranking method
Setting is in order to ensure that capacitance voltage is equal in the cycle, so as to realize the equilibrium of MMC submodule capacitor voltages so that MMC rectifications
The high-voltage dc voltage that device module 1 is exported is stable and reliable, and this method and step is simple, it is easy to accomplish；
Step 2: the decompression of the output high-voltage dc voltage of MMC rectifier module, process is as follows：
Step 201, partial pressure：Isolate output high voltage direct current of the subelement to MMC rectifier module 1 using multiple DC-DC
Pressure carries out partial pressure, using the derided capacitors in sub- inverter 2-1 and the bridge arm electric capacity to the defeated of MMC rectifier module 1
Go out high-voltage dc voltage and carry out two-stage partial pressure, obtain partial pressure DC voltage uFC；
Step 202, inversion：50% couple of partial pressure DC voltage u is respectively turned on using two IGBT in sub- inverter 2-1FC
Inversion is carried out, square wave alternating voltage is obtained；
Step 203, decompression：Sub- intermediate-frequency transformer 2-2 other side alternating current wave pressure progress, which is depressured, obtains low pressure square wave alternating-current electricity
Pressure；
Step 204, rectification and filtering：Sub- rectifier 2-3 carries out rectification to the low pressure square wave alternating voltage and obtains low pressure
DC voltage, and denoising is filtered to low-voltage dc voltage；
In the present embodiment, the quantity of derided capacitors is 10, and the voltage at 10 derided capacitors two ends is 2520V,
The quantity of the bridge arm electric capacity is 20, the partial pressure DC voltage u at 20 bridge arm electric capacity two endsFCFor 1260V, uFCBy
Two IGBT are respectively turned on the square wave alternating voltage that 50% inversion is ± 1260V, sub- intermediate-frequency transformer 2-2 no-load voltage ratio 1500:
1000, ± 1260V square wave alternating voltage are depressured the low pressure square wave alternating voltage for obtaining ± 840V through sub- intermediate-frequency transformer 2-2；
The low pressure square wave alternating voltage of ± 840V obtains 840V low-voltage dc voltage after sub- rectifier 2-3 rectifications；
Step 3: the inversion of low-voltage dc voltage, process is as follows：
Step 301, using DC-AC inverter 3 to low-voltage dc voltage carry out inversion, while measure DC-AC inverter 3 it is defeated
Go out side A phase instantaneous voltages uva, B phase instantaneous voltages uvbWith C phase instantaneous voltages uvc；
The DC-AC inverter 3 is three-phase full-bridge inverter, the three-phase full-bridge inverter and the low-voltage alternating-current power network
Between be connected with filter inductance；
Step 302, to A phase instantaneous voltages uva, B phase instantaneous voltages uvbWith C phase instantaneous voltages uvcDq conversion is carried out to obtain
DC-AC inverter d axle output voltages uvdWith DC-AC inverter q axle output voltages uvq；
Step 303, using the 3rd pi regulator to DC-AC inverter d axle output voltages uvdIt is defeated with DC-AC inverter q axles
Go out voltage uvqIt is adjusted, obtains DC-AC inverter d axle output voltage adjusted values uvd' and DC-AC inverter q axle output voltages
Adjusted value uvq', wherein,uvd *For DC-AC inverter d axle output voltages
Set reference value, uvq* reference value, K are set for DC-AC inverter q axles output voltagep 3For the proportionality coefficient of the 3rd pi regulator,
Ki 3For the integral coefficient of the 3rd pi regulator；
Step 304, to uvd' and uvq' dq inverse transformations are carried out, obtain three phase sine modulating wave；
Step 305, to the three phase sine modulating wave carry out Frequency conversion control, obtain in three-phase full-bridge inverting circuit
Trigger pulse, IGBT in three-phase full-bridge inverter is controlled according to the trigger pulse, exports symmetrical three phase sine alternating voltage；
Step 306, circulation step 301 to step 305, realize the inversion of low-voltage dc voltage.
In the present embodiment, according to formula
Set uvd *And uvq *, wherein, ω takes 314, and the aberration rate of three phase sine alternating voltage is 2.1%, meets national standard.
It is described above, only it is presently preferred embodiments of the present invention, not the present invention is imposed any restrictions, it is every according to the present invention
Any simple modification, change and equivalent structure change that technical spirit is made to above example, still fall within skill of the present invention
In the protection domain of art scheme.
Claims (6)
1. the power electronics distribution transformer based on MMC, it is characterised in that：Including be sequentially connected MMC rectifier module (1),
DC-DC isolators (2) and DC-AC inverter (3), input and the High-voltage AC Network (4) of the MMC rectifier module (1)
Connection, the output end of the DC-AC inverter (3) is connected with low-voltage alternating-current power network (5)；The DC-DC isolators (2) include many
Individual DC-DC isolates subelement, and the voltage input end of multiple DC-DC isolation subelements is sequentially connected in series in MMC rectifier
Between the DC output end of module (1), the output end of multiple DC-DC isolation subelements is connected in DC-AC inverter in parallel
(3) between direct-flow input end；Sub- inverter (2-1) that DC-DC isolation subelement includes being sequentially connected, sub- intermediate frequency transformation
Device (2-2) and sub- rectifier (2-3), the sub- inverter (2-1) are included by upper bridge arm electric capacity, upper bridge arm IGBT, lower bridge arm electricity
The single-phase full bridge inverter circuit of appearance and lower bridge arm IGBT compositions, the input parallel connection of the single-phase full bridge inverter circuit is connected to partial pressure
Electric capacity, the sub- rectifier (2-3) is that diode does not control bridge rectifier.
2. according to the power electronics distribution transformer based on MMC described in claim 1, it is characterised in that：The DC-AC inversions
Device (3) is three-phase full-bridge inverter, and filtered electrical is connected between the three-phase full-bridge inverter and the low-voltage alternating-current power network (5)
Sense.
3. according to the power electronics distribution transformer based on MMC described in claim 1, it is characterised in that：The diode is not
Controlling bridge rectifier includes diode-bridge circuit and the filter capacitor in parallel with the output end of the diode-bridge circuit.
4. according to the power electronics distribution transformer based on MMC described in claim 1, it is characterised in that：The MMC rectifier
Module (1) is the bridge arm circuit of three-phase six, per mutually including upper bridge arm and lower bridge arm, the upper bridge in the bridge arm circuit of three-phase six
Arm and the lower bridge arm include a current-limiting reactor and M MMC submodules being connected in series, and the M are connected in series
One end of submodule connects with one end of current-limiting reactor, the other end of the current-limiting reactor and the High-voltage AC Network phase
Connect, the other end of the MMC submodules being connected in series connects with the sub- inverter (2-1), the MMC submodules include half
Bridge circuit (1-1) and submodule electric capacity (1-2), the submodule electric capacity (1-2) and the half-bridge circuit (1-1) signal output part
It is in parallel.
5. according to the power electronics distribution transformer based on MMC described in claim 4, it is characterised in that：The half-bridge circuit
(1-1) half-bridge IGBT under half-bridge IGBT and MMC on MMC is constituted.
6. a kind of control method using the power electronics distribution transformer as claimed in claim 1 based on MMC, its feature exists
In the control method comprises the following steps：
Step 1: the rectification of High Level AC Voltage, process is as follows：
The A phase current instantaneous values i of step 101, in real time measurement High-voltage AC Network (4)A, A phase voltage instantaneous values uSA, B phase currents
Instantaneous value iB, B phase voltage instantaneous values uSB, C phase current instantaneous values iCWith C phase voltage instantaneous values uSC；
Step 102, according to formulaCalculate the A of High-voltage AC Network (4)
The positive-sequence component i of phase transient currentA +, B phase transient currents positive-sequence component iB +With the positive-sequence component i of C phase transient currentsC +；
According to formulaThe A phase currents for calculating High-voltage AC Network (4) are born
Order components iA -, B phase currents negative sequence component iB -With the negative sequence component i of C phase currentsC -；
According to formulaCalculate the A phases of High-voltage AC Network (4)
The positive-sequence component u of instantaneous voltageSA +, B phase instantaneous voltages positive-sequence component uSB +With the positive-sequence component u of C phase instantaneous voltagesSC +；Its
In, ω is the angular frequency of High-voltage AC Network (4) voltage；
According to formulaCalculate the A phases of High-voltage AC Network (4)
The negative sequence component u of instantaneous voltageSA -, B phase instantaneous voltages negative sequence component uSB -With the negative sequence component u of C phase instantaneous voltagesSC -；
Step 103, to iA +、iB +And iC +Q axle forward-order currents i can be obtained by carrying out dq conversionq +With d axle forward-order currents id +, to iA -、iB -With
iC -Q axle negative-sequence currents i can be obtained by carrying out dq conversionq -With d axle negative-sequence currents id -；
To uSA +、uSB +And uSC +Q axle positive sequence High-voltage AC Network instantaneous voltages u can be obtained by carrying out dq conversionSq +Handed over d axle positive sequences high pressure
Flow power network instantaneous voltage uSd +, to uSA -、uSB -And uSC -Q axle negative phase-sequence High-voltage AC Network instantaneous voltages u can be obtained by carrying out dq conversionSq -
With d axle negative phase-sequence High-voltage AC Network instantaneous voltages uSd -；
Step 104, using the first pi regulator MMC rectifier module output high-voltage dc voltage is adjusted, is obtaining d axles just
Sequence current reference value i* d +, wherein,uDC *Exported for MMC rectifier module
High-voltage dc voltage setting value, uDCHigh-voltage dc voltage real-time measurement values, K are exported for MMC rectifier modulep 1For described first
The proportionality coefficient of pi regulator, Ki 1For the integral coefficient of first pi regulator；
The MMC rectifier module (1) is the bridge arm circuit of three-phase six, per mutually including upper bridge arm in the bridge arm circuit of three-phase six
With lower bridge arm, the upper bridge arm and the lower bridge arm include a current-limiting reactor and the M MMC submodules being connected in series,
One end of submodule that the M is connected in series connect with one end of current-limiting reactor, the other end of the current-limiting reactor with
The High-voltage AC Network connects, and the other end of the submodule being connected in series connects with the sub- inverter (2-1), described
Submodule includes half-bridge circuit (1-1) and submodule electric capacity (1-2), the submodule electric capacity (1-2) and the half-bridge circuit (1-
1) signal output part is in parallel；
Step 105, using the second pi regulator to d axle forward-order currents reference value, q axle forward-order currents reference value, d axle negative-sequence currents
Reference value and q axle negative-sequence current reference values are adjusted, and according to formulaCalculate
MMC rectifier module d axle positive sequence input voltages uMd +With MMC rectifier module q axle positive sequence input voltages uMq +, according to formulaCalculate the input of d axle negative phase-sequence MMC rectifiers module
Voltage uMd -With q axle negative phase-sequence MMC rectifier module input voltages uMq -, wherein, iq +*For the reference value and i of q axle forward-order currentsq +*=
0, id -*For the reference value and i of d axle negative-sequence currentsd -*=0, iq -*For the reference value and i of q axle negative-sequence currentsq -*=0, Kp 2For second
The proportionality coefficient of pi regulator, Ki 2For the integral coefficient of the second pi regulator, L is the inductance value of the current-limiting reactor；
Step 106, to uMd +And uMq +Carry out dq inverse transformations and obtain MMC rectifier modules A phase positive sequence input voltage uMA +, B phase positive sequences
Input voltage uMB +With C phase positive sequence input voltages uMC +；To uMd -And uMq -Progress dq inverse transformations obtain MMC rectifier modules A and mutually born
Sequence input voltage uMA -, B phases negative sequence voltage input uMB -With C phase negative phase-sequence input voltages uMC -；According to formulaCalculate MMC rectifier modules A phase input voltage uMA, MMC rectifier module B phases input electricity
Press uMBWith MMC rectifier module C phase input voltages uMC；
Step 107, the quantity for obtaining each bridge arm input MMC submodules of the bridge arm circuit of three-phase six：To every in the bridge arm circuit of three-phase six
The MMC submodule input quantities of phase are determined respectively, and the MMC submodules input in the bridge arm circuit of three-phase six in any one phase
Number determination method all same；
When being determined to the MMC submodule input quantities in the bridge arm circuit of three-phase six per phase, process is as follows：
Step I, according to formulaCalculate the input number D under every phase on bridge arm in the bridge arm circuit of three-phase six1,
Wherein, ceil () is round up function, uMFor any one phase input voltage, u in MMC rectifier module three-phase voltagemmcFor
Submodule electric capacity rated voltage；
Step II, according to formula D2=M-D1, calculate the input number D in every phase on bridge arm in the bridge arm circuit of three-phase six2；
The output high-voltage dc voltage real-time measurement values u of step 108, MMC rectifier module (1)DCVoltage stabilizing：Pass through MMC submodules
Block capacitance voltage ranking method determines that the submodule that each bridge arm is put into completes the output HVDC to MMC rectifier module (1)
Voltage uDCVoltage stabilizing；
Step 109, circulation step 101 to step 108, are measured the output high-voltage dc voltage of MMC rectifier module (1) in real time
Value uDCExported；
Step 2: the decompression of the output high-voltage dc voltage of MMC rectifier module, process is as follows：
Step 201, partial pressure：Isolate output high-voltage dc voltage of the subelement to MMC rectifier module (1) using multiple DC-DC
Partial pressure is carried out, using the derided capacitors in sub- inverter (2-1) and the bridge arm electric capacity to MMC rectifier module (1)
Export high-voltage dc voltage and carry out two-stage partial pressure, obtain partial pressure DC voltage uFC；
Step 202, inversion：50% couple of partial pressure DC voltage u is respectively turned on using two IGBT in sub- inverter (2-1)FCEnter
Row inversion, obtains square wave alternating voltage；
Step 203, decompression：Sub- intermediate-frequency transformer (2-2) other side alternating current wave pressure progress, which is depressured, obtains low pressure square wave alternating voltage；
Step 204, rectification and filtering：Sub- rectifier (2-3) carries out rectification to the low pressure square wave alternating voltage and obtains low-pressure direct
Voltage is flowed, and denoising is filtered to low-voltage dc voltage；
Step 3: the inversion of low-voltage dc voltage, process is as follows：
Step 301, using DC-AC inverter (3) to low-voltage dc voltage carry out inversion, while measure DC-AC inverter (3) it is defeated
Go out side A phase instantaneous voltages uva, B phase instantaneous voltages uvbWith C phase instantaneous voltages uvc；
The DC-AC inverter (3) is three-phase full-bridge inverter, the three-phase full-bridge inverter and the low-voltage alternating-current power network it
Between be connected with filter inductance；
Step 302, to A phase instantaneous voltages uva, B phase instantaneous voltages uvbWith C phase instantaneous voltages uvcCarry out dq conversion and obtain DC-AC
Inverter d axle output voltages uvdWith DC-AC inverter q axle output voltages uvq；
Step 303, using the 3rd pi regulator to DC-AC inverter d axle output voltages uvdElectricity is exported with DC-AC inverter q axles
Press uvqIt is adjusted, obtains DC-AC inverter d axle output voltage adjusted values uvd' and the adjustment of DC-AC inverter q axles output voltage
Value uvq', wherein,uvd *Set for DC-AC inverter d axles output voltage
Reference value, uvq *Reference value, K are set for DC-AC inverter q axles output voltagep 3For the proportionality coefficient of the 3rd pi regulator, Ki 3For
The integral coefficient of 3rd pi regulator；
Step 304, to uvd' and uvq' dq inverse transformations are carried out, obtain three phase sine modulating wave；
Step 305, to the three phase sine modulating wave carry out Frequency conversion control, obtain the triggering in three-phase full-bridge inverting circuit
Pulse, IGBT in three-phase full-bridge inverter is controlled according to the trigger pulse, exports symmetrical three phase sine alternating voltage；
Step 306, circulation step 301 to step 305, realize the inversion of low-voltage dc voltage.
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| CN111030483A (en) * | 2019-12-30 | 2020-04-17 | 上海科梁信息工程股份有限公司 | Power electronic transformer and control method |
| CN111404409A (en) * | 2019-01-03 | 2020-07-10 | 南京南瑞继保工程技术有限公司 | Multi-port power electronic transformer topology based on MMC and control method thereof |
| WO2021016742A1 (en) * | 2019-07-26 | 2021-02-04 | Abb Schweiz Ag | Voltage converter |
| CN112467997A (en) * | 2019-09-06 | 2021-03-09 | 中国科学院电工研究所 | Flexible substation topology circuit and control method thereof |
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| WO2012037966A1 (en) * | 2010-09-21 | 2012-03-29 | Abb Technology Ag | An apparatus for controlling the electric power transmission in a hvdc power transmission system |
| CN104638940A (en) * | 2015-03-02 | 2015-05-20 | 东南大学 | Modular multi-level power electronic transformer based on cascading |
| CN106033931A (en) * | 2015-03-18 | 2016-10-19 | 山特电子（深圳）有限公司 | Bidirectional dc-dc converter and control method thereof |
| CN105553304A (en) * | 2016-01-15 | 2016-05-04 | 湖南大学 | Novel modular multi-level solid-state transformer and internal model control method thereof |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107645178A (en) * | 2017-09-08 | 2018-01-30 | 许继电气股份有限公司 | A kind of virtual synchronous machine control system and method based on electric power electric transformer |
| CN107645178B (en) * | 2017-09-08 | 2020-09-08 | 许继电气股份有限公司 | Virtual synchronous machine control system and method based on power electronic transformer |
| CN109029407A (en) * | 2018-06-25 | 2018-12-18 | 内江海德科技有限公司 | A kind of airborne vertical gyroscope of miniaturization |
| CN111404409A (en) * | 2019-01-03 | 2020-07-10 | 南京南瑞继保工程技术有限公司 | Multi-port power electronic transformer topology based on MMC and control method thereof |
| WO2021016742A1 (en) * | 2019-07-26 | 2021-02-04 | Abb Schweiz Ag | Voltage converter |
| CN112467997A (en) * | 2019-09-06 | 2021-03-09 | 中国科学院电工研究所 | Flexible substation topology circuit and control method thereof |
| CN111030483A (en) * | 2019-12-30 | 2020-04-17 | 上海科梁信息工程股份有限公司 | Power electronic transformer and control method |
| CN114094833A (en) * | 2021-10-29 | 2022-02-25 | 深圳供电局有限公司 | Switched capacitor access type direct current transformer and control method thereof |
| CN114094833B (en) * | 2021-10-29 | 2023-12-29 | 深圳供电局有限公司 | Switch capacitor access type direct current transformer and control method thereof |
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