CN107634659A - A kind of control method of expansion mixed type MMC operation areas - Google Patents
A kind of control method of expansion mixed type MMC operation areas Download PDFInfo
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Abstract
The invention discloses a kind of control method of expansion mixed type MMC operation areas, including the capacitance voltage of half-bridge submodule and the capacitance voltage of full-bridge submodule in detection in real time and more each mutually each bridge arm, if the difference between the two is more than voltage threshold Δ vc, by controlling full-bridge submodule and half-bridge submodule to turn on quantity, meet bridge arm output voltage in j phasesMeet bridge arm output voltage under j phasesThe charge and discharge area of increase half-bridge submodule is realized by changing upper and lower bridge arm current amplitude and phase, and then expands mixed type MMC operation areas；2 frequencys multiplication and 3 multiplied frequency harmonics are suppressed respectively to improve the performance of the two in AC and DC side simultaneously.It is the operation area that need not sacrifice transverter compared to traditional technical scheme, the characteristics of this programme, it is not necessary to increase the ratio of full-bridge submodule in mixed type MMC, while transverter also retains good fault ride-through capacity and AC pressure-raising service ability.
Description
Technical field
The invention belongs to multilevel power electronic converter technical field, expands mixed type MMC more particularly, to one kind
The control method of operation area.
Background technology
Two relatively conventional level and three-level converter, modularization multi-level converter easily realize higher voltage grade
And the application of more power grade, and it is topological as the first choice of high voltage direct current transmission device.Direct-current short circuit troubleshooting
Ability is the problem of high-voltage dc transmission electrical domain has to face.In numerous transverters for possessing direct-current short circuit troubleshooting capability
Among topology, half-bridge and full-bridge submodule number meet 1 in bridge arm:1 mixed type module multilevel converter possesses relatively low
Operating cost and higher operational efficiency.At present, the topology is by domestic high voltage direct current transmission converter valve goods producer
Favor.For the utilization rate of further increase power device, mixed type MMC can also be by increasing full-bridge submodule in bridge arm
Number is allowed to run on high alternating voltage operation occasion.In addition, mixed type MMC should possess certain low dc voltage service ability
To avoid the flashover of DC voltage under extreme weather.
When mixed type MMC runs on high modulation than under occasion, the full-bridge submodule in bridge arm needs to export negative level,
In one fundamental frequency cycles, the half-bridge submodule with bridge arm can continue charging (electric discharge), and the meeting continuous discharge of full-bridge submodule (is filled
Electricity), capacitance voltage persistently rises and capacitance voltage in full-bridge submodule continuous decrease or half-bridge submodule in half-bridge submodule
Lasting rise and full-bridge submodule continuous decrease, cause mixed type MMC can not normal operation, and then cause mixed type MMC to run
The small technical problem in region.
The content of the invention
For disadvantages described above, the invention provides a kind of control method of expansion mixed type MMC operation areas, it is intended to solves
Because half-bridge submodule persistently charges (electric discharge) in mixed type MMC and full-bridge submodule continuous discharge (charging) causes mixed type
MMC can not normal operation, and then cause the small technical problem in mixed type MMC operation areas.
To achieve the above object, the invention provides a kind of control method of expansion mixed type MMC operation areas, mixed type
MMC each bridge arm includes multiple full-bridge submodules and multiple half-bridge submodules, comprises the following steps：
(1) capacitance voltage of the capacitance voltage of half-bridge submodule and full-bridge submodule in each mutually each bridge arm is detected in real time；
(2) judge the capacitance voltage of the capacitance voltage of half-bridge submodule and full-bridge submodule in each mutually each bridge arm difference whether
More than voltage threshold, if so, then entering step (3)；Otherwise step (1) is continued executing with；
(3) by the way that jth phase sine-wave current is instructed, the jth phase circulation that detects in real time of mixed type MMC ACs and
Mixed type MMC DC sides electric current controls to obtain the first auxiliary voltage v of jth phase by ratio resonancej1；
By the jth phase circulation for detecting the instruction of the frequency multiplication circulation of jth phase two, mixed type MMC ACs in real time and mix
The second auxiliary voltage of jth phase v that mould assembly MMC DC sides electric current controls to obtain by ratio resonancej2；
Control to obtain jth phase by resonance with mixed type MMC DC sides electric current by the way that jth phase frequency tripling circulation is instructed
3rd auxiliary voltage vj3；
By the way that the instruction of the multiplied frequency harmonic of jth phase two is controlled to obtain jth with mixed type MMC ac-side currents by ratio resonance
4th auxiliary voltage v of phasej4；
By the way that bridge arm capacitance voltage under bridge arm capacitance voltage in jth phase and jth phase is controlled to obtain jth phase by ratio
5th auxiliary voltage vj5；
By controlling j phases bridge arm full-bridge submodule and half-bridge submodule to turn on quantity, meet bridge arm output voltage in j phasesMeet bridge arm output voltage under j phases
And j is allowed to travel through its value；By increasing the first auxiliary voltage to the 5th auxiliary voltage on upper and lower bridge arm, change each mutually upper and lower
Bridge arm current amplitude and phase, the charge and discharge area of increase half-bridge submodule is realized, and then expand mixed type MMC operation areas；
Wherein, vdcFor mixed type MMC DC side port voltages, ejFor electricity in the jth phase of mixed type MMC ACs output
Gesture, j=a, b, c, a, b, c represent A, B, C three-phases respectively；vj1For the first auxiliary voltage of jth phase；vj2Second for jth phase is attached
Making alive；vj3For the 3rd auxiliary voltage of jth phase；vj4For the 4th auxiliary voltage of jth phase；vj5For the 5th additional electrical of jth phase
Pressure.
Preferably, the phase of each phase jth phase sine-wave current instruction exchanges with respectively mixing type MMC in the step (3)
The phase of side output jth phase built-in potential differs 90 degree, and the frequency of each phase jth phase sine-wave current instruction is 50Hz；
If mixed type MMC runs on rectifier, the amplitude of each phase jth phase sine-wave current instruction meets that addition first is attached
Bridge arm current maximum after making alive and the second auxiliary voltage is more than 0.15 times of ac-side current amplitude, if mixed type MMC
Inverter is run on, then the amplitude of each phase jth phase sine-wave current instruction meets to add the first auxiliary voltage and the second additional electrical
Bridge arm current minimum value after pressure is less than minus 0.15 times of ac-side current amplitude.
Preferably, the first auxiliary voltage of jth phase is obtained in the step (3) according to following steps：
The jth phase circulation that mixed type MMC ACs are detected in real time and 1/3 mixed type MMC DC side current values
Difference as the high-order component in circulation；
The difference of the instruction of jth phase sine-wave current and the high-order component in circulation is carried out into ratio resonance to control to obtain jth
First auxiliary voltage of phase.
Preferably, the second auxiliary voltage of jth phase is obtained in the step (3) according to following steps：
The jth phase circulation that mixed type MMC ACs are detected in real time and 1/3 mixed type MMC DC side current values
Difference as the high-order component in circulation；
The difference of the instruction of the frequency multiplication circulation of jth phase two and the high-order component in circulation is carried out into ratio resonance to control to obtain jth
Second auxiliary voltage of phase, wherein, the frequency multiplication circulation command value of jth phase two is zero, and the jth phase circulation of mixed type MMC ACs leads to
Bridge arm current will be detected and lower bridge arm current is averaged acquisition by crossing.
Preferably, the 3rd auxiliary voltage of jth phase is obtained in the step (3) according to following steps：
The difference of the instruction of jth phase frequency tripling circulation and mixed type MMC DC side electric currents is subjected to resonance control and obtains jth phase
The 3rd auxiliary voltage, wherein, jth phase frequency tripling circulation command value is zero, and the jth phase circulation of mixed type MMC ACs passes through
It will detect bridge arm current and lower bridge arm current is averaged acquisition.
Preferably, the 4th auxiliary voltage of jth phase is obtained in the step (3) according to following steps：
The instruction of the multiplied frequency harmonic of jth phase two and the difference of mixed type MMC ac-side currents are controlled to obtain by ratio resonance
Jth phase the 4th auxiliary voltage, wherein, the multiplied frequency harmonic command value of jth phase two is zero.
Preferably, according to the number Δ N of bridge arm voltage determination sub-module switching in the step (3), and according to following suitable
Sequence switching submodule：
When bridge arm output voltage is just and bridge arm current is timing, it is minimum that selection puts into voltage sequence in all submodules
The N number of submodule of Δ or selection cut off the voltage sequence N number of submodule of highest Δ in all submodules；
When bridge arm output voltage is that selection puts into voltage sequence highest in all submodules just and when bridge arm current is negative
The N number of submodule of Δ or selection cut off the N number of submodule of Δ that voltage sequence is minimum in all submodules；
When bridge arm output voltage is that negative and bridge arm current is timing, selection puts into voltage in all full-bridge submodules and sorted most
The N number of submodule of high Δ or selection cut off the N number of submodule of Δ that voltage sequence is minimum in all full-bridge submodules；
When it is negative that bridge arm output voltage, which is negative and bridge arm current, selection puts into voltage in all full-bridge submodules and sorted most
The N number of submodule of low Δ or selection cut off the voltage sequence N number of submodule of highest Δ in all full-bridge submodules.
Further, in mixed type MMC full-bridge submodule and half-bridge submodule number proportioning can be arbitrarily on the occasion of.
By the contemplated above technical scheme of the present invention, compared with prior art, there is following technique effect：
1st, by adding the first auxiliary voltage to the 5th auxiliary voltage on upper and lower bridge arm, upper and lower bridge arm current width is changed
Value and phase, and then the charge and discharge area of increase half-bridge submodule is realized, realize half-bridge submodule discharge and recharge area and full-bridge
Module discharge and recharge area approaches, so avoid in half-bridge submodule capacitance voltage persistently rise and full-bridge submodule continuous decrease or
Capacitance voltage persistently rises and full-bridge submodule continuous decrease in person's half-bridge submodule, ensures that the operating point of alternating current-direct current side is constant
In the case of, and then the reliably working of transverter is realized, and then realize and expand mixed type MMC operation areas.
2nd, with using increasing in bridge arm compared with the scheme of the proportioning of full-bridge submodule, the program can be cost-effective, improves
Operational efficiency under normal operation.
3rd, it is symmetrically topological need not to change the upper and lower bridge arm of transverter for the contemplated scheme of the present invention, and then possesses good
DC Line Fault ride-through capability and exchange pressure-raising operation ability.
4th, the program is realized in AC by adding the 3rd auxiliary voltage and the 4th auxiliary voltage on upper and lower bridge arm
And DC side is suppressed to 2 frequencys multiplication and 3 multiplied frequency harmonics to improve the performance of the two respectively.
Brief description of the drawings
Fig. 1 is the topology of mixed type MMC in a kind of control method of expansion mixed type MMC operation areas provided by the invention
Structure；
Fig. 2 is a kind of flow chart of the control method of expansion mixed type MMC operation areas provided by the invention；
Fig. 3 is a kind of performance of the control method first embodiment of expansion mixed type MMC operation areas provided by the invention
The performance map of figure and the first comparative example, wherein, the performance map of the comparative examples of Fig. 3 (A) first, Fig. 3 (A) (a) is first
A cross streams output current wave in comparative example, Fig. 3 (A) (b) be the first comparative example in A phase circulation waveforms, Fig. 3 (A)
(c) it is the submodule capacitor voltage waveform in bridge arm under A phases in the first comparative example；Fig. 3 (B) (a) is A in first embodiment
Cross streams output current wave, Fig. 3 (B) (b) are A phase circulation waveforms in first embodiment, and Fig. 3 (B) (c) is in first embodiment
Submodule capacitor voltage waveform under A phases in bridge arm；
Fig. 4 is a kind of performance of the control method second embodiment of expansion mixed type MMC operation areas provided by the invention
The performance map of figure and the second comparative example, wherein, the performance map of the comparative examples of Fig. 4 (A) second, Fig. 4 (A) (a) is second
A cross streams output current wave in comparative example, Fig. 4 (A) (b) be the second comparative example in A phase circulation waveforms, Fig. 4 (A)
(c) it is the submodule capacitor voltage waveform in bridge arm under A phases in the second comparative example；Fig. 4 (B) (a) is A in second embodiment
Cross streams output current wave, Fig. 4 (B) (b) are A phase circulation waveforms in second embodiment, and Fig. 4 (B) (c) is in second embodiment
Submodule capacitor voltage waveform under A phases in bridge arm.
Embodiment
In order to make the purpose , technical scheme and advantage of the present invention be clearer, it is right below in conjunction with drawings and Examples
The present invention is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, and
It is not used in the restriction present invention.
Fig. 1 ties for the topology of mixed type MMC in the control method of expansion mixed type MMC operation areas provided by the invention
Structure, the upper bridge arm of connection alternating current j phases include multiple full-bridge submodules and multiple half-bridge submodules, connected under alternating current j phases
Bridge arm includes multiple full-bridge submodules and multiple half-bridge submodules, wherein, j=a, b, c, and a, b, c represent alternating current A respectively,
B, C phase, half-bridge submodule can export positive level and zero level, and full-bridge submodule can export positive level, negative level and zero electricity
It is flat.
Fig. 2 is the flow chart of the control method of expansion mixed type MMC operation areas provided by the invention；This method includes：
(1) capacitance voltage of the capacitance voltage of half-bridge submodule and full-bridge submodule in each mutually each bridge arm is detected in real time；
(2) judge the capacitance voltage of the capacitance voltage of half-bridge submodule and full-bridge submodule in each mutually each bridge arm difference whether
More than voltage threshold, if mutually the difference of the capacitance voltage of the capacitance voltage of half-bridge submodule and full-bridge submodule is more than in certain bridge arm for certain
Voltage threshold, then into step (3), otherwise perform step (1)；Voltage threshold determines that voltage threshold is general according to operation demand
For 0.1Vc, VcFor submodule rated voltage.
(3) by the way that jth phase sine-wave current is instructed, the jth phase circulation and mixed type MMC of mixed type MMC ACs
The first auxiliary voltage of jth phase v that DC side electric current controls to obtain by ratio resonancej1；Specifically, exchanged according to mixed type MMC
Difference between the jth phase circulation of side and the 1/3 of mixed type MMC DC side electric currents obtains the high-order component in circulation, and its is humorous
Ripple number is more than or equal to 1, and ratio resonance control is carried out after the instruction of jth phase sine-wave current is made the difference with the high-order component in circulation
Obtain the first auxiliary voltage v of jth phasej1。
Wherein, the resonant frequency that ratio resonance controls is 50Hz, and the jth phase circulation of mixed type MMC ACs will be by that will examine
Measure bridge arm current and lower bridge arm current is averaged acquisition, phase and the mixed type MMC of the instruction of jth phase sine-wave current are handed over
The phase for flowing side output jth phase built-in potential differs 90 degree, and the frequency of jth phase sine-wave current instruction is fundamental frequency；So that three-phase
Between sine-wave current instructing phase differ 120 degree successively, and meet positive order relation；
If mixed type MMC runs on rectifier, the amplitude of jth phase sine-wave current instruction should meet to add the first additional electrical
Pressure should be greater than 0.15 times of ac-side current amplitude with bridge arm current maxima after the second auxiliary voltage, if mixed type MMC is run
In inverter, then the amplitude that jth phase sine-wave current instructs should meet to add the first auxiliary voltage and the second auxiliary voltage back axle
Arm current minimum should be less than minus 0.15 times of ac-side current amplitude.
By the way that the frequency multiplication circulation of jth phase two is instructed, the jth phase circulation of mixed type MMC ACs and mixed type MMC direct currents
Side electric current controls to obtain the second auxiliary voltage v of jth phase by ratio resonancej2；Specifically, according to mixed type MMC ACs
Difference between jth phase circulation and the 1/3 of mixed type MMC DC side electric currents obtains the high-order component in circulation, its harmonic wave
Number is more than or equal to 1, and carrying out ratio resonance after the instruction of the multiplied frequency harmonic of jth phase two is made the difference with the high-order component in circulation controls to obtain
Second auxiliary voltage v of jth phasej2；Wherein, the frequency multiplication circulation of jth phase two instruction is zero, and the resonant frequency that ratio resonance controls is
100Hz, two harmonics of ac output current are suppressed with realizing.
Control to obtain jth phase by resonance with mixed type MMC DC sides electric current by the way that jth phase frequency tripling circulation is instructed
3rd auxiliary voltage vj3；Specifically, the difference of the instruction of jth phase frequency tripling circulation and mixed type MMC DC side electric currents is carried out humorous
Control of shaking obtains the 3rd auxiliary voltage v of jth phasej3；Wherein, jth phase frequency tripling circulation instruction is zero, the resonance frequency of resonance control
Rate is 150Hz, and the three times frequency component in DC current is aided in suppressing to realize.
By the way that the instruction of the multiplied frequency harmonic of jth phase two is controlled to obtain jth with mixed type MMC ac-side currents by ratio resonance
4th auxiliary voltage v of phasej4；Specifically, the instruction of the multiplied frequency harmonic of jth phase two and the difference of mixed type MMC ac-side currents are passed through
The ratio resonance of mistake controls the 4th auxiliary voltage v of obtained jth phasej4, wherein, the instruction of the multiplied frequency harmonic of jth phase two is zero, and ratio is humorous
The resonant frequency controlled of shaking is 100Hz, and two harmonics of ac output current are suppressed with realizing.
By the way that bridge arm capacitance voltage under bridge arm capacitance voltage in jth phase and jth phase is controlled to obtain jth phase by ratio
5th auxiliary voltage vj5。
By controlling full-bridge submodule and half-bridge submodule in j phase bridge arms to turn on quantity, meet bridge arm output voltage in j phasesMeet bridge arm output voltage under j phases
And j is allowed to travel through a, b, c.
Wherein, vdcFor mixed type MMC DC side port voltages, ejFor electricity in the jth phase of mixed type MMC ACs output
Gesture.
By adding the first auxiliary voltage to the 5th auxiliary voltage in upper and lower bridge arm, change j phase upper and lower bridge arm electric current width
Value and phase, realize that j phase half-bridge submodule discharge and recharge areas approach with full-bridge submodule discharge and recharge area, and then avoid half-bridge
In module capacitance voltage persistently rise and in full-bridge submodule continuous decrease or half-bridge submodule capacitance voltage persistently rise and
Full-bridge submodule continuous decrease, in the case of ensureing that the operating point of alternating current-direct current side is constant, and then the reliably working of transverter is realized,
And then realize and expand mixed type MMC operation areas.
In control method provided by the invention, the upper and lower bridge arm of each phase is using following switching submodules order
Rule.According to the number Δ N of bridge arm voltage determination sub-module switching, switching submodule, realization in the following order makes j phases
Upper bridge arm output voltage meetsMeet bridge arm output voltage under j phases
When bridge arm output voltage is just and bridge arm current is timing, it is minimum that selection puts into voltage sequence in all submodules
The N number of submodule of Δ or selection cut off the voltage sequence N number of submodule of highest Δ in all submodules, and submodule includes full-bridge
Module and half-bridge submodule；
When bridge arm output voltage is that selection puts into voltage sequence highest in all submodules just and when bridge arm current is negative
The N number of submodule of Δ or selection cut off the N number of submodule of Δ that voltage sequence is minimum in all submodules；
When bridge arm output voltage is that negative and bridge arm current is timing, selection puts into voltage in all full-bridge submodules and sorted most
The N number of submodule of high Δ or selection cut off the N number of submodule of Δ that voltage sequence is minimum in all full-bridge submodules；
When it is negative that bridge arm output voltage, which is negative and bridge arm current, selection puts into voltage in all full-bridge submodules and sorted most
The N number of submodule of low Δ or selection cut off the voltage sequence N number of submodule of highest Δ in all full-bridge submodules.
Physics of the control method of expansion mixed type MMC operation areas provided by the invention based on three-phase hybrid MMC is real
Platform is tested, the number of bridge arm full-bridge submodule and half-bridge submodule ratio is 2 in every phase:1, full-bridge submodule number is 2, electric capacity volume
Voltage ratio is determined for 1:1, it is 100V, the number of full-bridge submodule and half-bridge submodule ratio is 2 in bridge arm under every phase:1, full-bridge
Number of modules is 2, and electric capacity rated voltage ratio is 1:1, it is 100V；The specified electric V of DC side during normal operationdc=200V.
First embodiment and the first comparative example：
When MMC transverter band perseverance ohmic loads, the AC index of modulation by 1.8 liftings to 1.9, i.e., transimission power by
When 3.6kW rises to 4.0kW, using existing control method, the full-bridge submodule turned on by changing upper bridge arm and lower bridge arm
Number and half-bridge submodule number so that meet bridge arm output voltage in j phasesMake bridge arm under j phases defeated
Go out voltage to be equal toAs the first comparative example.First pair is shown successively from top to bottom in Fig. 3 (A)
The submodule capacitor voltage waveform of bridge arm under A phase currents in ratio, A phase circulations and A phases.As Fig. 3 A (c) can be had found in modulation system
After number rises, full-bridge submodule capacitor voltage declines always, and half-bridge submodule capacitor voltage rises always, when half-bridge submodule
When capacitance voltage rises to 120V or so, system closedown.
Using control method provided by the invention, the capacitance voltage and full-bridge submodule of half-bridge submodule in each mutually each bridge arm
When the difference of the capacitance voltage of block is more than voltage threshold 1.5V, by controlling full-bridge submodule and half-bridge submodule to turn on quantity, make j
Bridge arm output voltage meets in phaseMeet bridge arm output voltage under j phasesWherein, the amplitude of jth phase sine-wave current instruction is 6A.Fig. 3 B are arrived from above
Under show A phase currents in first embodiment successively, the submodule capacitor voltage waveform of bridge arm under A phase circulations and A phases.Such as Fig. 3 B
(c) it can find that submodule capacitor voltage keeps stable, be not present in a fundamental frequency cycles lasting rising or continuous decrease,
Mixed type MMC can be with long-play.
Second embodiment and the second comparative example：
When DC side rated voltage is dropped into by 200V under 160V and net side power factor be 1, transverter is to electrical grid transmission
Active power 2.4kW.Using existing control method, by change full-bridge submodule number that upper bridge arm and lower bridge arm turn on and
Half-bridge submodule number so that meet bridge arm output voltage in j phasesMake bridge arm output voltage under j phases
It is equal toAs the second comparative example.Fig. 4 A show DC voltage waveform, A successively from top to bottom
The submodule capacitor voltage waveform of bridge arm under phase circulation and A phases.As Fig. 4 A (c) can be had found after DC voltage falls, full-bridge
Module capacitance voltage declines always, and half-bridge submodule capacitor voltage rises always, when half-bridge submodule capacitor voltage rises to
During 120V or so, system closedown.
Using control method provided by the invention, the capacitance voltage and full-bridge submodule of half-bridge submodule in each mutually each bridge arm
When the difference of the capacitance voltage of block is more than voltage threshold 1.5V, by controlling full-bridge submodule and half-bridge submodule to turn on quantity, make j
Bridge arm output voltage meets in phaseMeet bridge arm output voltage under j phasesWherein, the amplitude of jth phase sine-wave current instruction is 4.2A.Fig. 4 B are by upper
Show DC voltage waveform successively under, the submodule capacitor voltage waveform of bridge arm under A phase circulations and A phases.Such as Fig. 4 B (c)
It can find that submodule capacitor voltage keeps stable, be not present in a fundamental frequency cycles lasting rising or continuous decrease, mix
Mould assembly MMC can be with long-play.
As it will be easily appreciated by one skilled in the art that the foregoing is merely illustrative of the preferred embodiments of the present invention, not to
The limitation present invention, all any modification, equivalent and improvement made within the spirit and principles of the invention etc., all should be included
Within protection scope of the present invention.
Claims (8)
1. a kind of control method of expansion mixed type MMC operation areas, each bridge arm of the mixed type MMC is comprising multiple complete
Bridge submodule and multiple half-bridge submodules, it is characterised in that comprise the following steps：
(1) capacitance voltage of the capacitance voltage of half-bridge submodule and full-bridge submodule in each mutually each bridge arm is detected in real time；
(2) judge whether the difference of the capacitance voltage of the capacitance voltage of half-bridge submodule and full-bridge submodule in each mutually each bridge arm is more than
Voltage threshold, if so, then entering step (3)；Otherwise step (1) is performed；
(3) by the way that jth phase sine-wave current is instructed, mixed type MMC jth phase circulation and mixed type MMC DC side electric currents
Control to obtain the first auxiliary voltage v of jth phase by ratio resonancej1；
By the way that the instruction of the frequency multiplication circulation of jth phase two, the jth phase circulation of mixed type MMC ACs and mixed type MMC DC sides is electric
Stream controls to obtain the second auxiliary voltage v of jth phase by ratio resonancej2；
Control to obtain the 3rd of jth phase by resonance with mixed type MMC DC sides electric current by the way that jth phase frequency tripling circulation is instructed
Auxiliary voltage vj3；
Control to obtain jth phase by ratio resonance with mixed type MMC ac-side currents by the way that the multiplied frequency harmonic of jth phase two is instructed
4th auxiliary voltage vj4；
By the way that bridge arm capacitance voltage under bridge arm capacitance voltage in jth phase and jth phase is controlled to obtain the 5th of jth phase by ratio
Auxiliary voltage vj5；
By controlling j phases bridge arm full-bridge submodule and half-bridge submodule to turn on quantity, meet bridge arm output voltage in j phasesMeet bridge arm output voltage under j phases
And j is allowed to travel through its value；By increasing the first auxiliary voltage to the 5th auxiliary voltage on upper and lower bridge arm, change each mutually upper and lower
Bridge arm current amplitude and phase, the charge and discharge area of increase half-bridge submodule is realized, and then expand mixed type MMC operation areas；
Wherein, vdcFor mixed type MMC DC side port voltages, ejFor the jth phase built-in potential of mixed type MMC ACs output, j=
A, b, c, a, b, c represent A, B, C three-phases respectively；vj1For the first auxiliary voltage of jth phase；vj2For the second additional electrical of jth phase
Pressure；vj3For the 3rd auxiliary voltage of jth phase；vj4For the 4th auxiliary voltage of jth phase；vj5For the 5th auxiliary voltage of jth phase.
2. control method according to claim 1, it is characterised in that jth phase sine-wave current described in the step (3)
The phase of instruction differs 90 degree with the phase of mixed type MMC ACs output jth phase built-in potential, and the jth is mutually sinusoidal
The frequency of ripple current-order is 50Hz；
If mixed type MMC runs on rectifier, the amplitude of the jth phase sine-wave current instruction meets to add the first additional electrical
Bridge arm current maximum after pressure and the second auxiliary voltage is more than 0.15 times of ac-side current amplitude, if mixed type MMC is run
In inverter, then the amplitude that the jth phase sine-wave current instructs meets after adding the first auxiliary voltage and the second auxiliary voltage
Bridge arm current minimum value be less than minus 0.15 times of ac-side current amplitude.
3. control method according to claim 1 or 2, it is characterised in that obtained in the step (3) according to following steps
First auxiliary voltage of the jth phase：
Using the difference of the jth phase circulation of mixed type MMC ACs and 1/3 mixed type MMC DC side current values as circulation
In high-order component；
The difference of jth phase sine-wave current instruction and the high-order component in the circulation is carried out into ratio resonance to control to obtain
First auxiliary voltage of the jth phase.
4. according to the control method described in any one of claims 1 to 3, it is characterised in that according to following step in the step (3)
Suddenly the second auxiliary voltage of the jth phase is obtained：
Using the difference of the jth phase circulation of mixed type MMC ACs and 1/3 mixed type MMC DC side current values as circulation
In high-order component；
By the difference of the instruction of the frequency multiplication circulation of jth phase two and the high-order component in the circulation carry out ratio resonance control to obtain it is described
Second auxiliary voltage of jth phase, wherein, the frequency multiplication circulation command value of jth phase two is zero, the jth phase circulation of mixed type MMC ACs
By that will detect upper bridge arm current and lower bridge arm current is averaged acquisition.
5. control method according to any one of claim 1 to 4, it is characterised in that according to as follows in the step (3)
Step obtains the 3rd auxiliary voltage of the jth phase：
The difference of jth phase frequency tripling circulation instruction and the mixed type MMC DC side electric currents is carried out into resonance control to obtain
3rd auxiliary voltage of jth phase, wherein, jth phase frequency tripling circulation command value is zero, the jth phase circulation of mixed type MMC ACs
By that will detect upper bridge arm current and lower bridge arm current is averaged acquisition.
6. control method according to any one of claim 1 to 5, it is characterised in that according to as follows in the step (3)
Step obtains the 4th auxiliary voltage of the jth phase：
Described in the instruction of the multiplied frequency harmonic of jth phase two and the differences of mixed type MMC ac-side currents are controlled to obtain by ratio resonance
4th auxiliary voltage of jth phase, wherein, the multiplied frequency harmonic command value of jth phase two is zero.
7. control method according to any one of claim 1 to 6, it is characterised in that according to bridge arm in the step (3)
The number Δ N of voltage determination sub-module switching, and switching submodule in the following order：
When bridge arm output voltage is just and bridge arm current is timing, selection puts into voltage in all submodules and sorted minimum Δ N
Individual submodule or selection cut off the voltage sequence N number of submodule of highest Δ in all submodules；
When bridge arm output voltage is that selection puts into voltage sequence highest Δ N in all submodules just and when bridge arm current is negative
Individual submodule or selection cut off the N number of submodule of Δ that voltage sequence is minimum in all submodules；
When bridge arm output voltage is that negative and bridge arm current is timing, selection puts into voltage sequence highest in all full-bridge submodules
The N number of submodule of Δ or selection cut off the N number of submodule of Δ that voltage sequence is minimum in all full-bridge submodules；
When it is negative that bridge arm output voltage, which is negative and bridge arm current, it is minimum that selection puts into voltage sequence in all full-bridge submodules
The N number of submodule of Δ or selection cut off the voltage sequence N number of submodule of highest Δ in all full-bridge submodules.
8. control method according to any one of claim 1 to 7, it is characterised in that full-bridge submodule in mixed type MMC
With half-bridge submodule number proportioning can be arbitrarily on the occasion of.
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| CN108880310A (en) * | 2018-08-03 | 2018-11-23 | 上海海事大学 | A kind of phase-shifting carrier wave modulator approach of middle pressure mixing module multi-level converter |
| CN110798090A (en) * | 2019-11-26 | 2020-02-14 | 浙江大学 | Combined modular multilevel converter topology and modulation method thereof |
| CN111693898A (en) * | 2020-05-18 | 2020-09-22 | 西安交通大学 | Accelerated positioning method for IGBT open-circuit fault in modular multilevel converter |
| CN112134470A (en) * | 2020-08-07 | 2020-12-25 | 国网浙江省电力有限公司电力科学研究院 | Submodule proportion constraint determining method for realizing reliable charging of mixed MMC (Modular multilevel converter) |
| CN113949259A (en) * | 2021-12-21 | 2022-01-18 | 浙江日风电气股份有限公司 | NPC three-level shutdown control method, device and system |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108880310A (en) * | 2018-08-03 | 2018-11-23 | 上海海事大学 | A kind of phase-shifting carrier wave modulator approach of middle pressure mixing module multi-level converter |
| CN110798090A (en) * | 2019-11-26 | 2020-02-14 | 浙江大学 | Combined modular multilevel converter topology and modulation method thereof |
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| CN112134470B (en) * | 2020-08-07 | 2021-08-27 | 国网浙江省电力有限公司电力科学研究院 | Submodule proportion constraint determining method for realizing reliable charging of mixed MMC (Modular multilevel converter) |
| CN114069686A (en) * | 2021-11-29 | 2022-02-18 | 特变电工西安柔性输配电有限公司 | Combined loss reduction method for power module of flexible direct current transmission system |
| CN113949259A (en) * | 2021-12-21 | 2022-01-18 | 浙江日风电气股份有限公司 | NPC three-level shutdown control method, device and system |
| CN113949259B (en) * | 2021-12-21 | 2022-03-01 | 浙江日风电气股份有限公司 | NPC three-level shutdown control method, device and system |
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