CN105356780B

CN105356780B - The modulator approach and system of submodule mixed type module Multilevel Inverters

Info

Publication number: CN105356780B
Application number: CN201510706087.9A
Authority: CN
Inventors: 魏承志; 练睿; 文安; 赵曼勇; 饶宏; 李岩; 曾勇刚; 许树楷; 黄维芳; 牟敏; 金鑫; 叶睆
Original assignee: China Southern Power Grid Co Ltd; Research Institute of Southern Power Grid Co Ltd
Current assignee: China Southern Power Grid Co Ltd; Research Institute of Southern Power Grid Co Ltd
Priority date: 2015-10-23
Filing date: 2015-10-23
Publication date: 2018-03-30
Anticipated expiration: 2035-10-23
Also published as: CN105356780A

Abstract

The present invention relates to the modulator approach and system of submodule mixed type module Multilevel Inverters, according to often treating each other output order voltage waveform, it is determined that in per phase bridge arm each submodule modulating wave, wherein, the modulating wave of the submodule includes the modulating wave of half-bridge submodule and the modulating wave of full-bridge submodule, the caused control signal compared with the modulating wave of each submodule of the carrier wave of each submodule according to every phase bridge arm, control respectively per each submodule input or cut-out in phase bridge arm, the output voltage waveforms of the submodule put into every phase bridge arm are superimposed, obtain every phase bridge arm output voltage waveforms.The modulating wave of half-bridge submodule is used to be modulated with the carrier wave of half-bridge submodule, the modulating wave of full-bridge submodule is used to be modulated with the carrier wave of full-bridge submodule, so as to realize the accurate modulation to mixed type submodule carrier wave and modulating wave, be advantageous to improve the quality of submodule mixed type module current transformer output voltage waveforms.

Description

The modulator approach and system of submodule mixed type module Multilevel Inverters

Technical field

The present invention relates to the modulation methods of electric field, more particularly to a seed module mixed type module Multilevel Inverters Method and system.

Background technology

After the topological structure of modularization multilevel converter (MMC) is suggested to, using MMC D.C. high voltage transmission (HVDC) system receives more and more attention, using also more extensive.MMC-HVDC systems use modular structure, existing MMC every phase bridge arm include upper bridge arm and lower bridge arm, be connected in parallel on direct current network positive and negative end per phase bridge arm, the upper bridge per phase Arm includes N number of submodule connected and the bridge arm inductance connected with the submodule, the upper bridge per phase with lower bridge arm The bridge arm inductance of the bridge arm inductance of arm and the lower bridge arm is connected in series.

MMC is widely used in DC transmission system, and DC side failure is difficult to avoid that.The MMC-HVDC to put into operation several at this stage Engineering, the basic submodules of MMC are all used as using half-bridge submodule (Half-bridge sub-module, HBSM), it is actual at present Semi-bridge type MMC used in engineering does not possess short trouble isolating power, but semiconductor devices is few used by it, passes through the most Ji.Bridge-type MMC is formed using full-bridge submodule (Full-bridge sub-module, FBSM), full-bridge submodule is compared to half Bridge submodule, full-bridge submodule can be by IGBT (insulated gate bipolar transistor) shut-off limiting short-circuit currents, still All being doubled for the quantity of IGBT and diode, it is with high costs.With reference to the advantage of half-bridge submodule and full-bridge submodule, propose In submodule mixed type MMC, the MMC of this structure, full-bridge submodule and half-bridge submodule, and full-bridge submodule quantity are contained Reach certain proportion.

One of necessary condition of MMC normal works is rational modulation system, for pure semi-bridge type MMC or pure bridge-types MMC, conventional modulation system have carrier wave to be laminated (Phase position, PD), phase-shifting carrier wave (Phase shifted Carrier, PSC) and nearest level approach (Nearest level modulation, NLM), MMC output is made by modulation Approach sine wave.Multiple PWM (pulse width modulation) ripple is superimposed by carrier wave stacking by different level, but using carrier wave stacking modulation methods Formula.It is that the out of phase PWM ripples of multiple carrier waves stack up, for approaching sine wave using phase-shifting carrier wave modulation system.Using Nearest level modulation mode, by the output of programme-control submodule, sine wave is approached so as to generate staircase waveform.However, it is directed to Submodule mixed type MMC, original modulation system for being directed to pure bridge-type MMC devices and pure semi-bridge type MMC do not apply to simultaneously, because In submodule mixed type MMC topological structures, the existing full-bridge submodule of a bridge arm has half-bridge submodule again, both submodule works Make state and pattern is different from, and original modulation system is entered in the case of having identical mode of operation based on each submodule Row work, so using original modulation system when, submodule mixed type MMC output voltage waveforms quality can be caused not It is high.

The content of the invention

Based on this, it is necessary to for causing submodule mixed type module Multilevel Inverters defeated using existing modulator approach The problem of voltage waveform gone out is second-rate, there is provided how electric the submodule mixed type moduleization that can improve output voltage waveforms quality is The modulator approach and system of flat current transformer.

The modulator approach of one seed module mixed type module Multilevel Inverters, the submodule mixed type module are more The upper bridge arm of every phase bridge arm of level current transformer includes N number of submodule connected with lower bridge arm, and N number of submodule includes M half Bridge submodule and N-M full-bridge submodule, wherein, the N is positive integer, and the M is positive integer, and the N is more than the M；

The modulator approach of the submodule mixed type module Multilevel Inverters comprises the following steps：

According to often treating each other output order voltage waveform, it is determined that in per phase bridge arm each submodule modulating wave, wherein, it is described The modulating wave of submodule includes the modulating wave of half-bridge submodule and the modulating wave of full-bridge submodule；

It is determined that in per phase bridge arm each submodule carrier frequency and carrier phase；

According to the carrier frequency of each submodule and the carrier phase in every phase bridge arm, it is determined that per in phase bridge arm The carrier wave of each submodule；

By the carrier wave of each submodule described in every phase bridge arm compared with the modulating wave of each submodule, generation Input to the control signal of each submodule described in every phase bridge arm；

According to each control signal, control per each submodule input or cut-out in phase bridge arm, obtained per phase bridge arm respectively Described in each submodule output voltage waveforms；

The output voltage waveforms of the submodule put into every phase bridge arm are superimposed, obtain the submodule mixed type module Every phase bridge arm output voltage waveforms of Multilevel Inverters.

The present invention also provides the modulating system of a seed module mixed type module Multilevel Inverters, and the submodule mixes The upper bridge arm of every phase bridge arm of mould assembly modular multi-level converter includes N number of submodule connected, N number of submodule with lower bridge arm Block includes M half-bridge submodule and N-M full-bridge submodule, wherein, the N is positive integer, and the M is positive integer, the N More than the M；

The modulating system of the submodule mixed type module Multilevel Inverters includes：

First determining module, output order voltage waveform is often treated each other for basis, it is determined that each submodule in per phase bridge arm Modulating wave, wherein, the modulating wave of the submodule includes the modulating wave of half-bridge submodule and the modulating wave of full-bridge submodule；

Second determining module, for determining the carrier frequency and carrier phase of each submodule in every phase bridge arm；

3rd determining module, for according to the carrier frequency of each submodule and the carrier wave phase in every phase bridge arm Position, it is determined that each carrier wave of submodule in per phase bridge arm；

Comparison module, for by the carrier wave of each submodule described in every phase bridge arm and each submodule

Modulating wave is compared, the control signal of generation input to each submodule described in every phase bridge arm；

Acquisition module, for according to each control signal, controlling respectively per each submodule input or cut-out in phase bridge arm, Obtain the output voltage waveforms per each submodule described in phase bridge arm；

Processing module, for the output voltage waveforms superposition for the submodule that will be put into every phase bridge arm, obtain the submodule Every phase bridge arm output voltage waveforms of block mixed type module Multilevel Inverters.

The modulator approach and system of above-mentioned submodule mixed type module Multilevel Inverters, according to often treating each other output order Voltage waveform, it is determined that each modulating wave of submodule in per phase bridge arm, wherein, the modulating wave of the submodule includes half-bridge submodule The modulating wave of block and the modulating wave of full-bridge submodule, by the carrier wave of each submodule described in every phase bridge arm and each submodule The modulating wave of block is compared, the control signal of generation input to each submodule described in every phase bridge arm, according to each control Signal processed, control per each submodule input or cut-out in phase bridge arm, obtained per the defeated of each submodule described in phase bridge arm respectively Go out voltage waveform, the output voltage waveforms of the submodule put into every phase bridge arm are superimposed, obtain the submodule mixing mould Every phase bridge arm output voltage waveforms of block Multilevel Inverters.Because the modulating wave of the submodule of determination includes half-bridge submodule Modulating wave and full-bridge submodule modulating wave, the modulating wave of half-bridge submodule is used to be adjusted with the carrier wave of half-bridge submodule System, the modulating wave of full-bridge submodule are used to be modulated with the carrier wave of full-bridge submodule, mixed type submodule are carried so as to realize The accurate modulation of ripple and modulating wave, be advantageous to improve the quality of submodule mixed type module current transformer output voltage waveforms.

Brief description of the drawings

Fig. 1 is the structural representation of submodule mixed type module Multilevel Inverters；

Fig. 2 is the structural representation of half-bridge submodule；

Fig. 3 is the structural representation of full-bridge submodule；

Fig. 4 is a kind of flow chart of the modulator approach of the submodule mixed type module Multilevel Inverters of embodiment；

Fig. 5 is pure half-bridge module Multilevel Inverters and pure full-bridge modules Multilevel Inverters structural representation；

Fig. 6 is the sub-process of the modulator approach of the submodule mixed type module Multilevel Inverters of another embodiment Figure；

Fig. 7 is the sub-process of the modulator approach of the submodule mixed type module Multilevel Inverters of another embodiment Figure；

Fig. 8 is the sub-process of the modulator approach of the submodule mixed type module Multilevel Inverters of another embodiment Figure；

Fig. 9 is that submodule mixed type module Multilevel Inverters phase-shifting carrier wave modulates schematic diagram；

Figure 10 is the modulating wave and carrier wave figure of the half-bridge submodule of upper and lower bridge arm；

Figure 11 is the modulating wave and carrier wave figure of the full-bridge submodule of upper and lower bridge arm；

Figure 12 is the PWM waveform figure of modulating wave and triangular carrier relatively gained；

Figure 13 is submodule output voltage waveform；

Figure 14 is the bridge arm voltage after the superposition of submodule output voltage waveforms；

Figure 15 is a kind of module map of the modulating system of the submodule mixed type module Multilevel Inverters of embodiment；

Figure 16 is the submodule of the modulating system of the submodule mixed type module Multilevel Inverters of another embodiment Block figure；

Figure 17 is the submodule of the modulating system of the submodule mixed type module Multilevel Inverters of another embodiment Block figure.

Embodiment

Referring to Fig. 1, the upper bridge arm and lower bridge arm of every phase bridge arm of submodule mixed type module Multilevel Inverters are equal Including the submodule of N number of series connection, N number of submodule includes M half-bridge submodule and N-M full-bridge submodule, wherein, the N For positive integer, the M is positive integer, and the N is more than the M.

Referring to Fig. 2, half-bridge submodule includes the first IGBT pipes T1, the 2nd IGBT pipes T2, the first sustained diode 1, the Two sustained diodes 2 and the first electric capacity C1, the first IGBT pipes T1 colelctor electrode are connected with the first electric capacity C1 one end, and first The electric capacity C1 other end is connected with the 2nd IGBT pipes T2 emitter stage, the positive pole of the first sustained diode 1 and the first IGBT pipes T1 Emitter stage connection, negative pole be connected with the first IGBT pipes T1 colelctor electrode, and the 2nd IGBT pipes T2 colelctor electrode connects and first IGBT pipes T1 emitter stage connection, the positive pole of the second sustained diode 2 is connected with the 2nd IGBT pipes T2 emitter stage, negative pole and 2nd IGBT pipes T2 colelctor electrode connection, the first IGBT pipes T1 and the 2nd IGBT pipes T2 base stage receive external equipment offer Control signal, control signal is received by base stage, control IGBT pipes are turned on and off.First IGBT pipes T1 and the 2nd IGBT pipes T2 is to turn in turn.

Referring to Fig. 3, full-bridge submodule includes the 3rd IGBT pipes T3, the 4th IGBT pipes T4, the 5th IGBT pipes T5, the 6th IGBT pipes T6, the 3rd sustained diode 3, the 4th sustained diode 4, the 5th sustained diode 5, the 6th sustained diode 6 And second electric capacity C2, the 3rd IGBT pipes T3 colelctor electrode, the 4th IGBT pipes T4 colelctor electrode and the second electric capacity C2 one end It is connected, the 3rd IGBT pipes T3 emitter stage is connected with the 5th IGBT pipes T5 colelctor electrode, the 5th IGBT pipes T5 emitter stage, the 6th IGBT pipes T6 emitter stage and the second electric capacity C2 other end are connected, the 4th IGBT pipes T4 emitter stage and the 6th IGBT pipes T6 Colelctor electrode connection, the positive pole of the 3rd sustained diode 3 is connected with the 3rd IGBT pipes T3 emitter stage, negative pole and the 3rd IGBT Pipe T3 colelctor electrode connection, the positive pole of the 4th sustained diode 4 are connected with the 4th IGBT pipes D4 emitter stage, negative pole and the 4th IGBT pipes T4 colelctor electrode connection, the positive pole of the 5th sustained diode 5 is connected with the 5th IGBT pipes T5 emitter stage, negative pole and 5th IGBT pipes T5 colelctor electrode connection, the positive pole of the 6th sustained diode 6 are connected with the 6th IGBT pipes T6 emitter stage, born Pole is connected with the 6th IGBT pipes T6 colelctor electrode, the 3rd IGBT pipes T3, the 4th IGBT pipes T4, the 5th IGBT pipes T5 and the 6th IGBT pipes T6 base stage receives the control signal of foreign currency equipment offer.3rd IGBT pipes T3 and the 5th IGBT pipes T5 is wheel conductance Logical, the 4th IGBT pipes T4 and the 6th IGBT pipes T6 are also to turn in turn.

By carrier wave and modulation wave modulation, the drive signal for driving each submodule is produced, the more level of drive moduleization become Being turned on and off for the IGBT pipes in device Neutron module is flowed, reasonably controls input and the excision of each phase submodule, and then control The quantity of the submodule effectively to be worked in per phase bridge arm, the voltage waveform that the submodule of input exports is overlapped, so as to The modulator approaches different close to the exchange output of modulating wave to modular multi-level converter can make modular multilevel unsteady flow The ac output voltage of the output of device is different.

Referring to Fig. 4, a kind of modulator approach of the submodule mixed type module Multilevel Inverters of embodiment is provided,

S100：According to output order voltage waveform is often treated each other, it is determined that each modulating wave of submodule in per phase bridge arm.

Wherein, the modulating wave of submodule includes the modulating wave of half-bridge submodule and the modulating wave of full-bridge submodule.Pass through son DC voltage is converted to alternating voltage output by module mixed type module Multilevel Inverters, and command voltage waveform to be output is Refer to the voltage waveform for being expected that by submodule mixed type module Multilevel Inverters output.Due to passing through carrier wave and modulating wave Modulation, the input of control submodule mixed type module Multilevel Inverters Neutron module and excision, to the submodule of input Output voltage be overlapped the output voltage for obtaining the output of submodule mixed type module Multilevel Inverters close to modulating wave Waveform, output order voltage waveform is often treated each other so as to basis, it is determined that each modulating wave of submodule in per phase bridge arm, so may be used The output voltage waveforms of submodule mixed type module Multilevel Inverters are made to be more nearly desired output waveform.

S200：It is determined that in per phase bridge arm each submodule carrier frequency and carrier phase.

Determining the parameter of carrier wave includes carrier frequency and carrier phase, so as to need to carrier frequency and carrier phase progress It is selected.

S300：According to the carrier frequency and carrier phase of each submodule in every phase bridge arm, it is determined that every in per phase bridge arm The carrier wave of individual submodule.

After carrier frequency and carrier phase determine, carrier wave also determines therewith.

S400：By the carrier wave of each submodule in every phase bridge arm compared with the modulating wave of each submodule, generation is defeated Enter into every phase bridge arm the control signal of each submodule.

By the comparison of carrier wave and modulating wave, the control signal for driving each submodule is produced, when the modulating wave of submodule is big When the carrier wave of submodule, high ordinary mail number is produced, when modulating wave is less than carrier wave, produces LOW signal.

S500：According to each control signal, control per each submodule input or cut-out in phase bridge arm, obtained per phase bridge arm respectively In each submodule output voltage waveforms.

By the comparison of carrier wave and modulating wave, the control signal for driving each submodule is produced, according to each control signal, difference Each submodule input or cut-out in the every phase bridge arm of control.When the modulating wave of submodule is more than the carrier wave of submodule, Gao Ping is produced Signal, high ordinary mail number input to the base stage of the first IGBT pipes turn it on, and are inputted after high ordinary mail number reversion to the 2nd IGBT pipes Base stage makes its closing.When modulating wave is less than carrier wave, LOW signal is produced, LOW signal, which is inputted to the first IGBT pipes, makes its pass Close, input to the 2nd IGBT pipes turn it on after LOW signal reversion.According to the situation that is turned on and off of IGBT pipes, submodule is controlled Block is put into or cut-out, i.e., the output voltage of control submodule is identical with electric capacity both end voltage, represents submodule input, controls submodule The output voltage of block is 0, submodule excision is represented, so as to obtain the output voltage waveforms of each submodule in every phase bridge arm.

S600：The output voltage waveforms of the submodule put into every phase bridge arm are superimposed, obtain submodule mixed type module Change every phase bridge arm output voltage waveforms of Multilevel Inverters.

The modulator approach of above-mentioned submodule mixed type module Multilevel Inverters, according to often treating each other output order voltage wave Shape, it is determined that each modulating wave of submodule in per phase bridge arm, wherein, the modulating wave of the submodule includes the tune of half-bridge submodule The modulating wave of ripple and full-bridge submodule processed, by the tune of the carrier wave of each submodule described in every phase bridge arm and each submodule Ripple processed is compared, the control signal of generation input to each submodule described in every phase bridge arm, according to each control signal, Control respectively per each submodule input or cut-out in phase bridge arm, obtain the output voltage ripple per each submodule described in phase bridge arm Shape, the output voltage waveforms of the submodule put into every phase bridge arm are superimposed, how electric obtain the submodule mixed type moduleization Every phase bridge arm output voltage waveforms of flat current transformer.Because the modulating wave of the submodule of determination includes the modulating wave of half-bridge submodule With the modulating wave of full-bridge submodule, the modulating wave of half-bridge submodule is used to be modulated with the carrier wave of half-bridge submodule, full-bridge The modulating wave of module is used to be modulated with the carrier wave of full-bridge submodule, so as to realize to mixed type submodule carrier wave and modulating wave Accurate modulation, be advantageous to improve submodule mixed type module current transformer output voltage waveforms quality.

Specifically, the modulator approach of above-mentioned submodule mixed type module Multilevel Inverters includes complete suitable for bridge arm The submodule mixed type module Multilevel Inverters of bridge submodule and half-bridge submodule two types submodule, pure half-bridge pattern Block Multilevel Inverters and pure bridge-type modular multi-level converter can regard sensu lato submodule mixing mould as Block Multilevel Inverters, it is how electric that above-mentioned modulator approach is equally applicable to the modularization as shown in Figure 5 containing only half-bridge submodule Flat current transformer or the modular multi-level converter containing only full-bridge submodule, i.e., above-mentioned modulator approach are equally applicable to M equal to N's Pure semi-bridge type modular multi-level converter or M are equal to 0 pure bridge-type modular multi-level converter.Fig. 5 (a) represents do not have The pure semi-bridge type modular multi-level converter structure chart of full-bridge submodel, Fig. 5 (b) represent the pure full-bridge of no half-bridge submodel Type modular multi-level converter structure chart.

Referring to Fig. 6, in one of the embodiments, according to output order voltage waveform is often treated each other, it is determined that per phase bridge arm In the modulating wave S100 of each submodule be specially：

S110：Translated, overturn and the processing of at least one of stretching conversion to often treating each other output order voltage waveform, Or the modulating wave that will often treat each other output order voltage waveform and be defined as every phase bridge arm Neutron module, obtain per in phase bridge arm per height The modulating wave of module.

Due to command voltage waveform to be output refer to be expected that by the submodule mixed type module Multilevel Inverters it is defeated The voltage waveform gone out, and submodule mixed type module Multilevel Inverters output voltage waveforms are close to modulating wave, so as to treat Output order voltage waveform carries out conversion process, obtains the modulating wave of submodule, or directly determine command voltage waveform to be output Justice is the modulating wave of submodule, makes submodule mixed type module Multilevel Inverters output voltage ripple close to instruction electricity to be output Corrugating, i.e., close to desired output waveform.

Referring to Fig. 7, in one of the embodiments, often treat each other output order voltage waveform to described and translated, turn over Turn and the processing of at least one of stretching conversion, or often treat each other output order voltage waveform by described and be defined as every phase bridge arm neutron The modulating wave of module, obtain and specifically include step per the modulating wave S110 of each submodule in phase bridge arm：

S1101：Overturn to often treating each other output order voltage waveform, obtain each half-bridge of the upper bridge arm per phase bridge arm The modulating wave of submodule；

S1102：Each half-bridge submodule output order voltage waveform will often be treated each other be defined as the lower bridge arm of every phase bridge arm Modulating wave；

S1103：Overturn and translated to often treating each other output order voltage waveform, obtain the every of upper bridge arm per phase bridge arm First modulating wave of individual full-bridge submodule；

S1104：Translated to often treating each other output order voltage waveform, obtain each full-bridge of the upper bridge arm per phase bridge arm Second modulating wave of submodule；

S1105：Translated to often treating each other output order voltage waveform, obtain each full-bridge of the lower bridge arm per phase bridge arm 3rd modulating wave of submodule；

S1106：Overturn and translated to often treating each other output order voltage waveform, obtain the every of lower bridge arm per phase bridge arm 4th modulating wave of individual full-bridge submodule.

Wherein, the specific formula of the modulating wave of each half-bridge submodule of the upper bridge arm of the every phase bridge arm of acquisition is：

The specific formula for obtaining the modulating wave of each half-bridge submodule of the lower bridge arm per phase bridge arm is：

The specific formula for obtaining the first modulating wave of each full-bridge submodule of the upper bridge arm per phase bridge arm is：

The specific formula for obtaining the second modulating wave of each full-bridge submodule of the upper bridge arm per phase bridge arm is：

The 3rd specific formula of modulating wave for obtaining each full-bridge submodule of the lower bridge arm per phase bridge arm is：

The 4th specific formula of modulating wave for obtaining each full-bridge submodule of the lower bridge arm per phase bridge arm is；

In formula, u_{ref_j}Treating each other output order voltage waveform for jth, j takes A, B or C, represents A phases, B phases or C phases respectively, u_{half_j-}For the modulating wave of the half-bridge submodule of the upper bridge arm of jth phase, u_{half_j+}For the half-bridge submodule of the lower bridge arm of jth phase Modulating wave, u_{full1_j-}For the first modulating wave of the full-bridge submodule of bridge arm in jth phase, u_{full2_j-}For the full-bridge of bridge arm in jth phase Second modulating wave of submodule, u_{full3_j+}For the 3rd modulating wave of the full-bridge submodule of bridge arm under jth phase, u_{full4_j+}For jth phase 4th modulating wave of the full-bridge submodule of lower bridge arm, M represent modulation depth,For phase voltage virtual value, ω is instruction to be output Voltage waveform frequency,For command voltage waveform first phase to be output.

Referring to Fig. 8, in one of the embodiments, by the carrier wave of each submodule in every phase bridge arm and each submodule Modulating wave be compared, generation input into every phase bridge arm the control signal S400 of each submodule specifically include step：

S410：By each of the carrier wave of each half-bridge submodule of the upper bridge arm of every phase bridge arm and the upper bridge arm per phase bridge arm The modulating wave of half-bridge submodule is compared, the control letter of generation input to each half-bridge submodule of the upper bridge arm of every phase bridge arm Number.

The control signal is inputted to each half-bridge submodule of the upper bridge arm of every phase bridge arm, controls the upper bridge per phase bridge arm The input of each half-bridge submodule of arm and excision.

S420：By each of the carrier wave of each half-bridge submodule of the lower bridge arm of every phase bridge arm and the lower bridge arm per phase bridge arm The modulating wave of half-bridge submodule is compared, the control letter of generation input to each half-bridge submodule of the lower bridge arm of every phase bridge arm Number.

The control signal is inputted to each half-bridge submodule of the lower bridge arm of every phase bridge arm, controls the lower bridge per phase bridge arm The input of each half-bridge submodule of arm and excision.

S430：By each of the carrier wave of each full-bridge submodule of the upper bridge arm of every phase bridge arm and the upper bridge arm per phase bridge arm The first modulating wave and the second modulating wave of full-bridge submodule are compared respectively, the upper bridge arm of generation input to every phase bridge arm The first control signal and the second control signal of each full-bridge submodule.

The 3rd IGBT pipes and the 4th IGBT pipes in the full-bridge submodule of the caused upper bridge arm of first control signal control It is turned on and off, the 5th IGBT pipes and the 6th IGBT pipes in the full-bridge submodule of the caused upper bridge arm of second control signal control Be turned on and off, so as to realize the input of the full-bridge submodule of the upper bridge arm of control and excision.

S440：By each of the carrier wave of each full-bridge submodule of the lower bridge arm of every phase bridge arm and the lower bridge arm per phase bridge arm 3rd modulating wave of full-bridge submodule and the 4th modulating wave are compared respectively, the lower bridge arm of generation input to every phase bridge arm The 3rd control signal and the 4th control signal of each full-bridge submodule.

The 3rd IGBT pipes and the 4th IGBT pipes in the full-bridge submodule of the caused lower bridge arm of 3rd control signal control It is turned on and off, the 5th IGBT pipes and the 6th IGBT pipes in the full-bridge submodule of the caused lower bridge arm of 4th control signal control Be turned on and off, so as to realize the input of the full-bridge submodule of the lower bridge arm of control and excision.

In one of the embodiments, the carrier frequency of half-bridge submodule is the carrier frequency of full-bridge submodule in every phase bridge arm Twice of rate, the reference phase of the submodule of the upper bridge arm per phase bridge arm be followed successively by 0,2 π/N, 2 × 2 π/N ..., (N-1) × 2 π/N, the reference phase of the submodule of the lower bridge arm per phase bridge arm be followed successively by 0,2 π/N, 2 × 2 π/N ..., (N-1) × 2 π/N, per phase bridge arm in the carrier phase of full-bridge submodule be followed successively by the reference phase of submodule divided by 2 add π/4, every phase bridge arm The carrier phase of middle half-bridge submodule is maintained reference phase.

In order that half-bridge submodule and full-bridge submodule cooperate, the carrier frequency and full-bridge submodule of half-bridge submodule Equivalent carrier frequency it is identical, the carrier phase of half-bridge submodule is identical with the equivalent carrier phase of full-bridge submodule, due to complete Modulating wave and triangular carrier ratio in PWM waveform and Figure 12 that the carrier wave of bridge submodule and the modulating wave of full-bridge submodule relatively obtain It is consistent compared with the PWM waveform of gained, thus can as the bridge for linking up full-bridge submodule and half-bridge submodule, full-bridge submodule etc. Twice of the carrier frequency that carrier frequency is full submodule is imitated, so as to the load that the carrier frequency of half-bridge submodule is full-bridge submodule Twice of wave frequency rate.In order that submodule mixed type module Multilevel Inverters output voltage waveforms approach sine as far as possible Ripple, carries out phase shift to carrier wave, the equivalent carrier phase of full-bridge submodule for the carrier phase of full-bridge submodule be multiplied by 2 subtract again π/ 2, the reference phase of the submodule of upper bridge arm be followed successively by 0,2 π/N, 2 × 2 π/N ..., (N-1) × 2 π/N, the son of lower bridge arm The reference phase of module be followed successively by 0,2 π/N, 2 × 2 π/N ..., (N-1) × 2 π/N, half-bridge submodule carrier phase dimension Phase on the basis of holding, the equivalent carrier phase of full-bridge submodule also maintains the reference phase of submodule constant successively, according to full-bridge The relation of the equivalent carrier phase of submodule and the carrier phase of full-bridge submodule, it is known that the carrier phase of full-bridge submodule is successively Reference phase divided by 2 for submodule add π/4.

The modulator approach of above-mentioned submodule mixed type module Multilevel Inverters is illustrated with being embodied below.

Illustrated with a phase of three-phase submodule mixed type module Multilevel Inverters in Fig. 1, that is, analyze A phases, B A phase in phase and C phases, can be pushed into the other phases of current transformer with class, the submodule mixed type module for utilizing the present embodiment to provide The schematic diagram that the phase-shifting carrier wave modulator approach of Multilevel Inverters is modulated is as shown in Figure 9.Main devices have wave converter, Triangular carrier generator and comparator, wave converter are connected with comparator, and triangular carrier generator is connected with comparator, ripple Shape transformer produces modulating wave, and triangular carrier generator produces carrier wave, and comparator is used for modulating wave compared with carrier wave.Press According to function, Fig. 9 is broadly divided into following components：Half-bridge submodule modulating wave occurs, and full-bridge submodule modulating wave occurs, and three Angle carrier wave sequence occurs and main circuit part, and output voltage waveforms are mainly realized in main circuit part.Modulating wave and carrier wave are carried out Compare, generate the control signal of IGBT in submodule, wherein, the half-bridge submodule IGBT control signals of lower bridge arm pass through such as Figure 10 The modulating wave of the half-bridge submodule of shown lower bridge arm produces compared with the carrier wave of the half-bridge submodule of lower bridge arm, upper bridge arm The half-bridge submodule IGBT control signals half-bridge submodule that passes through the upper bridge arm in Figure 10 modulating wave and upper bridge arm half-bridge The carrier wave of submodule, which produces, is compared generation, and the full-bridge submodule IGBT control signals of lower bridge arm are by under as shown in figure 11 The carrier wave ratio of the modulating wave of the full-bridge submodule of bridge arm and the full-bridge submodule of lower bridge arm relatively produces, the full-bridge submodule of upper bridge arm The carrier wave of modulating wave and the full-bridge submodule of upper bridge arm that IGBT control signals pass through the full-bridge submodule of the upper bridge arm in Figure 11 It is compared generation.

The modulating wave of the modulating wave of half-bridge submodule and full-bridge submodule, half-bridge submodule and full-bridge submodule is determined first It can be translated, be overturn or the processing of at least one of stretching conversion obtains by treating output waveform command voltage waveform, or Waveform command voltage waveform to be output is defined as to the modulating wave of submodule, so as to obtain the modulating wave of submodule, it is assumed that jth phase Instructional waveform voltage waveform u to be output_{ref_j}For：

Wherein, j takes A, B or C, represents A phases, B phases or C phases, u respectively_{half_j-}For the half-bridge submodule of the upper bridge arm of jth phase Modulating wave, M represent modulation depth,For phase voltage virtual value, ω is command voltage waveform frequency to be output,To be to be output Command voltage waveform first phase.Wave parameter and modulation depth is modulated to be determined according to current transformer control algolithm.

The half-bridge submodule modulating wave u of bridge arm and lower bridge arm in generation_{half_j-}And u_{half_j+}, specific formula is as follows：

The waveform exported per bridge arm under phase is and u_{ref_j}With the sine wave of phase, per phase on bridge arm output waveform be with u_{ref_j}Anti-phase sine wave.I.e. using stretching conversion and turning-over changed, half-bridge submodule modulating wave can be also generated.

Regenerate full-bridge submodule modulating wave.Wherein it is determined that the first modulating wave of the full-bridge submodule of the upper bridge arm of every phase Specific formula be：

It is determined that the specific formula of the second modulating wave of the full-bridge submodule of the upper bridge arm of every phase is：

It is determined that the specific formula of the 3rd modulating wave of the full-bridge submodule of the lower bridge arm of every phase is：

It is determined that the specific formula of the 4th modulating wave of the full-bridge submodule of the lower bridge arm of every phase is；

Equally, using stretching, translation and it is turning-over changed, this four waveforms can also be obtained.It refer to full-bridge submodule in Fig. 3 Block schematic diagram.u_{full3_j+}With u_{full4_j+}Bridge arm full-bridge submodule under corresponding transverter, u_{full3_j+}Full-bridge submodule in corresponding lower bridge arm The 3rd IGBT pipes T3 and the 4th IGBT pipe T4, u in block_{full4_j+}In corresponding lower bridge arm the 5th IGBT pipes T5 of full-bridge submodule and 6th IGBT pipes T6.u_{full1_j-}And u_{full2_j-}Bridge arm full-bridge submodule on corresponding transverter, u_{full1_j-}Full-bridge in bridge arm in correspondence The 3rd IGBT pipes T3 and the 4th IGBT pipe T4, u in submodule_{full2_j-}The 5th IGBT of full-bridge submodule is managed in bridge arm in correspondence T5 and the 6th IGBT pipes T6.

It is then determined that triangular carrier C corresponding to each submodule in per the upper bridge arm in phase bridge arm and lower bridge arm₁、 C₂、……、C_i、……、C_N。C₁Represent the 1st triangular carrier, C corresponding to submodule₂Represent the 2nd triangle corresponding to submodule Carrier wave, C_iRepresent triangular carrier corresponding to i-th of submodule, C_NTriangular carrier corresponding to representing n-th submodule, will determine three Angle carrier wave, two parameters are mainly determined, be the frequency and phase of triangular carrier respectively.If all full-bridge submodule triangular carrier works Working frequency is k_f, the working frequency of all half-bridge submodule triangular carriers is k_h, triangular carrier C₁、C₂、……、C_i、……、C_N's Phase is respectively θ₁,θ₂,…,θ_i,…,θ_N, θ₁Represent the phase of the 1st triangular carrier corresponding to submodule, θ₂Represent the 2nd son The phase of triangular carrier corresponding to module, θ_iRepresent the phase of triangular carrier corresponding to i-th of submodule, θ_NRepresent n-th submodule The phase of triangular carrier corresponding to block, the bridge arm voltage to generate modulation approaches sine wave as far as possible, therefore needs to enter carrier wave Each reference phase corresponding to submodule is respectively 0,2 π/N, 2 × 2 π/N ... ..., (i- in row phase shift, upper bridge arm and lower bridge arm 1) × 2 π/N ... ..., (N-1) × 2 π/N.

But for full-bridge submodule, triangular carrier and modulating wave u_{full1_j-}、u_{full2_j-}、u_{full3_j+}And u_{full4_j+}Carry out Compare the modulating wave u that the PWM waveform modulated is different from triangular carrier and half-bridge submodule_{half_j-}And u_{half_j+}Compare modulation The PWM waveform gone out.For enable the modulating wave of full-bridge submodule and PWM waveform and the carrier wave of half-bridge submodule that carrier modulation goes out and The PWM waveform that modulating wave modulates cooperates, it is necessary to handle the carrier wave of full-bridge submodule.

Modulating wave and triangle in PWM waveform and Figure 12 that full-bridge submodule carrier wave and full-bridge submodule modulating wave relatively obtain Carrier wave ratio is consistent compared with the PWM waveform of gained, thus can be as the bridge for linking up full-bridge submodule and half-bridge submodule.In fact, In Figure 12 waveform be Figure 11 in correspond to waveform by the doubling of abscissa axis gained, by the carrier wave of full-bridge submodule in Figure 12 referred to as etc. Carrier wave is imitated, is designated as C '₁,C′₂,…,C′_i,…,C′_N。

Therefore, to make half-bridge submodule and full-bridge submodule cooperate, triangular carrier and full-bridge of half-bridge submodule The identical frequency of the equivalent carrier wave of module, and reference phase is followed successively by 0,2 π/N, 2 × 2 π/N ... ..., (i-1) × 2 π/N ... ..., (N- 1)×2π/N.Equivalent carrier frequency is 2 times of carrier frequency, so to make full-bridge submodule triangular carrier frequency and half-bridge submodule Triangular carrier frequency is identical, should meet k_h=2k_f, k_hFor the carrier frequency of half-bridge submodule, k_fFor the carrier frequency of full-bridge submodule Rate.

Relation between full-bridge submodule carrier wave and equivalent carrier wave is：

Thus, make half-bridge submodule carrier wave and the equivalent carrier phase of full-bridge submodule is respectively 0,2 π/N, 2 × 2 π/ N ... ..., (i-1) × 2 π/N ... ..., (N-1) × 2 π/N, this sequence phase is designated as θ '_i, θ '_iRepresent i-th of sub- full-bridge The equivalent carrier phase of module, i are more than or equal to 0, and are less than or equal to N, expression full-bridge submodule equivalent phase, to full-bridge submodule, Actual phase θ is obtained according to above formula backstepping_i, i.e., the phase of triangular carrier corresponding to i-th of submodule, using actual phase as complete The phase of bridge submodule triangular carrier.

Half-bridge submodule modulating wave, full-bridge submodule modulating wave, half-bridge submodule triangular wave, full-bridge submodule three is determined After the carrier wave of angle, you can be modulated, the control signal for controlling each submodule, the input of control submodule and excision produced, by son The output voltage waveforms of module are overlapped, and obtain the output voltage waveforms of submodule mixed type module current transformer.

Such as Figure 13, each submodule output voltage waveforms are PWM ripples, and each PWM ripples are by being equivalent to same modulating wave institute Modulation, so these PWM ripple fundamental waves are identical, but by being modulated each PWM for causing to be modulated by the carrier wave of out of phase Had differences between ripple, final bridge arm voltage is the superposition of these PWM ripples having differences, and as shown in figure 14, is obtained after superposition Bridge arm voltage approach sine wave.

The present invention also provides a kind of modulating system of the submodule mixed type module Multilevel Inverters of embodiment, its In, the upper bridge arm of every phase of submodule mixed type module Multilevel Inverters includes N number of submodule connected with lower bridge arm, N number of submodule includes M half-bridge submodule and N-M full-bridge submodule.

Figure 15 is referred to, the modulating system of above-mentioned submodule mixed type module Multilevel Inverters includes：

First determining module 100, output order voltage waveform is often treated each other for basis, it is determined that each submodule in per phase bridge arm The modulating wave of block.

Second determining module 200, for determining the carrier frequency and carrier phase of each submodule in every phase bridge arm.

3rd determining module 300, for according to the carrier frequency of each submodule and the load in every phase bridge arm Wave phase, it is determined that each carrier wave of submodule in per phase bridge arm.

Comparison module 400, for by the tune of the carrier wave of each submodule described in every phase bridge arm and each submodule Ripple processed is compared, the control signal of generation input to each submodule described in every phase bridge arm.

Acquisition module 500, for according to each control signal, controlling per each submodule input in phase bridge arm or cutting respectively It is disconnected, obtain the output voltage waveforms per each submodule described in phase bridge arm.

Processing module 600, for the output voltage waveforms superposition for the submodule that will be put into every phase bridge arm, obtain the son Every phase bridge arm output voltage waveforms of module mixed type module Multilevel Inverters.

The modulating system of above-mentioned submodule mixed type module Multilevel Inverters, according to often treating each other output order voltage wave Shape, it is determined that each modulating wave of submodule in per phase bridge arm, wherein, the modulating wave of the submodule includes the tune of half-bridge submodule The modulating wave of ripple and full-bridge submodule processed, by the tune of the carrier wave of each submodule described in every phase bridge arm and each submodule Ripple processed is compared, the control signal of generation input to each submodule described in every phase bridge arm, according to each control signal, Control respectively per each submodule input or cut-out in phase bridge arm, obtain the output voltage ripple per each submodule described in phase bridge arm Shape, the output voltage waveforms of the submodule put into every phase bridge arm are superimposed, how electric obtain the submodule mixed type moduleization Every phase bridge arm output voltage waveforms of flat current transformer.Because the modulating wave of the submodule of determination includes the modulating wave of half-bridge submodule With the modulating wave of full-bridge submodule, the modulating wave of half-bridge submodule is used to be modulated with the carrier wave of half-bridge submodule, full-bridge The modulating wave of module is used to be modulated with the carrier wave of full-bridge submodule, so as to realize to mixed type submodule carrier wave and modulating wave Accurate modulation, be advantageous to improve submodule mixed type module current transformer output voltage waveforms quality.

Specifically, the modulating system of above-mentioned submodule mixed type module Multilevel Inverters includes complete suitable for bridge arm The submodule mixed type module Multilevel Inverters of bridge submodule and half-bridge submodule two types submodule, pure half-bridge pattern Block Multilevel Inverters and pure bridge-type modular multi-level converter can regard sensu lato submodule mixing mould as Block Multilevel Inverters, it is how electric that above-mentioned modulating system is equally applicable to the modularization as shown in Figure 5 containing only half-bridge submodule Flat current transformer or the modular multi-level converter containing only full-bridge submodule.Fig. 5 (a) represents the pure half-bridge of no full-bridge submodel Type modular multi-level converter structure chart, Fig. 5 (b) represent the pure bridge-type modular multilevel unsteady flow of no half-bridge submodel Device structure chart.

In one of the embodiments, the first determining module 100, specifically for often treating each other output order voltage wave to described Shape translated, is overturn and the processing of at least one of stretching conversion, or often treats each other the definition of output order voltage waveform by described For the modulating wave of every phase bridge arm Neutron module, the modulating wave per each submodule in phase bridge arm is obtained.

Figure 16 is referred to, in one of the embodiments, the first determining module 100 includes：

First determining unit 110, for being overturn to often treating each other output order voltage waveform, obtain per the upper of phase bridge arm The modulating wave of each half-bridge submodule of bridge arm.

Second determining unit 120, for will often treat each other output order voltage waveform and be defined as the lower bridge arm of every phase bridge arm The modulating wave of each half-bridge submodule.

3rd determining unit 130, for being overturn and being translated to often treating each other output order voltage waveform, obtain per phase bridge First modulating wave of each full-bridge submodule of the upper bridge arm of arm.

4th determining unit 140, for being translated to often treating each other output order voltage waveform, obtain per the upper of phase bridge arm Second modulating wave of each full-bridge submodule of bridge arm.

5th determining unit 150, for being translated to often treating each other output order voltage waveform, obtain per under phase bridge arm 3rd modulating wave of each full-bridge submodule of bridge arm.

6th determining unit 160, for being overturn and being translated to often treating each other output order voltage waveform, obtain per phase bridge 4th modulating wave of each full-bridge submodule of the lower bridge arm of arm.

Figure 17 is referred to, in one of the embodiments, comparison module 400 includes：

First comparing unit 410, for by the carrier wave of each half-bridge submodule of the upper bridge arm of every phase bridge arm and per phase bridge The modulating wave of each half-bridge submodule of the upper bridge arm of arm is compared, and each the half of the upper bridge arm of generation input to every phase bridge arm The control signal of bridge submodule.

Second comparing unit 420, for by the carrier wave of each half-bridge submodule of the lower bridge arm of every phase bridge arm and per phase bridge The modulating wave of each half-bridge submodule of the lower bridge arm of arm is compared, and each the half of the lower bridge arm of generation input to every phase bridge arm The control signal of bridge submodule.

3rd comparing unit 430, for by the carrier wave of each full-bridge submodule of the upper bridge arm of every phase bridge arm and per phase bridge The first modulating wave and the second modulating wave of each full-bridge submodule of the upper bridge arm of arm are compared respectively, and generation is inputted to every The first control signal and the second control signal of each full-bridge submodule of the upper bridge arm of phase bridge arm.

4th comparing unit 440, for by the carrier wave of each full-bridge submodule of the lower bridge arm of every phase bridge arm and per phase bridge The 3rd modulating wave and the 4th modulating wave of each full-bridge submodule of the lower bridge arm of arm are compared respectively, and generation is inputted to every The 3rd control signal and the 4th control signal of each full-bridge submodule of the lower bridge arm of phase bridge arm.

In order that half-bridge submodule and full-bridge submodule cooperate, the carrier frequency and full-bridge submodule of half-bridge submodule Equivalent carrier frequency it is identical, the carrier phase of half-bridge submodule is identical with the equivalent carrier phase of full-bridge submodule, due to complete Modulating wave and triangular carrier ratio in PWM waveform and Figure 12 that the carrier wave of bridge submodule and the modulating wave of full-bridge submodule relatively obtain It is consistent compared with the PWM waveform of gained, thus can as the bridge for linking up full-bridge submodule and half-bridge submodule, full-bridge submodule etc. Twice of the carrier frequency that carrier frequency is full submodule is imitated, so as to the load that the carrier frequency of half-bridge submodule is full-bridge submodule Twice of wave frequency rate.In order that submodule mixed type module Multilevel Inverters output voltage waveforms approach sine as far as possible Ripple, carries out phase shift to carrier wave, the equivalent carrier phase of full-bridge submodule for the carrier phase of full-bridge submodule be multiplied by 2 subtract again π/ 2, the reference phase of the submodule of the submodule of upper bridge arm be followed successively by 0,2 π/N, 2 × 2 π/N ..., (N-1) × 2 π/N, under The reference phase of the submodule of bridge arm be followed successively by 0,2 π/N, 2 × 2 π/N ..., (N-1) × 2 π/N, the load of half-bridge submodule Wave phase is maintained reference phase, and the equivalent carrier phase of full-bridge submodule also maintains the reference phase of submodule constant successively, According to the equivalent carrier phase of full-bridge submodule and the relation of the carrier phase of full-bridge submodule, it is known that the carrier wave of full-bridge submodule Phase is followed successively by the reference phase of submodule divided by 2 adds π/4.

Above example only expresses the several embodiments of the present invention, and its description is more specific and detailed, but can not Therefore it is construed as limiting the scope of the patent.It should be pointed out that for the person of ordinary skill of the art, On the premise of not departing from present inventive concept, various modifications and improvements can be made, these belong to protection scope of the present invention. Therefore, the protection domain of patent of the present invention should be determined by the appended claims.

Claims

1. how electric the modulator approach of a seed module mixed type module Multilevel Inverters, the submodule mixed type moduleization be The upper bridge arm of every phase bridge arm of flat current transformer includes N number of submodule connected with lower bridge arm, and N number of submodule includes M half-bridge Submodule and N-M full-bridge submodule, wherein, the N is positive integer, and the M is positive integer, and the N is more than the M, its It is characterised by,

According to often treating each other output order voltage waveform, it is determined that in per phase bridge arm each submodule modulating wave, wherein, the submodule The modulating wave of block includes the modulating wave of half-bridge submodule and the modulating wave of full-bridge submodule；

According to the carrier frequency of each submodule and the carrier phase in every phase bridge arm, it is determined that each in per phase bridge arm The carrier wave of submodule；

According to each control signal, control per each submodule input or cut-out in phase bridge arm, obtained per institute in phase bridge arm respectively State the output voltage waveforms of each submodule；

The output voltage waveforms of the submodule put into every phase bridge arm are superimposed, how electric obtain the submodule mixed type moduleization Every phase bridge arm output voltage waveforms of flat current transformer.

2. the modulator approach of submodule mixed type module Multilevel Inverters according to claim 1, it is characterised in that The basis often treats each other output order voltage waveform, it is determined that the modulating wave of each submodule is specially in per phase bridge arm：

Often treat each other output order voltage waveform to described and translated, overturn and the processing of at least one of stretching conversion, or will The modulating wave often treated each other output order voltage waveform and be defined as every phase bridge arm Neutron module, is obtained described per phase bridge arm In each submodule modulating wave.

3. the modulator approach of submodule mixed type module Multilevel Inverters according to claim 2, it is characterised in that It is described often to treat each other output order voltage waveform to described and translated, overturn and the processing of at least one of stretching conversion, or will The modulating wave often treated each other output order voltage waveform and be defined as every phase bridge arm Neutron module, is obtained described per phase bridge arm In each submodule modulating wave the step of include：

Often treat each other output order voltage waveform to described and overturn, obtain each half-bridge submodule of the upper bridge arm per phase bridge arm Modulating wave；

By it is described often treat each other output order voltage waveform be defined as every phase bridge arm lower bridge arm each half-bridge submodule modulation Ripple；

Often treat each other output order voltage waveform to described and overturn and translated, obtain each full-bridge of the upper bridge arm per phase bridge arm First modulating wave of submodule；

Often treat each other output order voltage waveform to described and translate, obtain each full-bridge submodule of the upper bridge arm per phase bridge arm The second modulating wave；

Often treat each other output order voltage waveform to described and translate, obtain each full-bridge submodule of the lower bridge arm per phase bridge arm The 3rd modulating wave；

Often treat each other output order voltage waveform to described and overturn and translated, obtain each full-bridge of the lower bridge arm per phase bridge arm 4th modulating wave of submodule；

Wherein, the specific formula of the modulating wave of each half-bridge submodule of the acquisition upper bridge arm per phase bridge arm is：

In formula, the u_{ref_j}Treat each other output order voltage waveform for jth, the j takes A, B or C, represents A phases, B phases or C respectively Phase, the u_{half_j-}For the modulating wave of the half-bridge submodule of the upper bridge arm of jth phase, the u_{half_j+}For the half of the lower bridge arm of jth phase The modulating wave of bridge submodule, the u_{full1_j-}For the first modulating wave of the full-bridge submodule of bridge arm in jth phase, the u_{full2_j-} For the second modulating wave of the full-bridge submodule of bridge arm in jth phase, the u_{full3_j+}For of the full-bridge submodule of bridge arm under jth phase Three modulating waves, the u_{full4_j+}For the 4th modulating wave of the full-bridge submodule of bridge arm under jth phase, the M represents modulation depth, institute StateFor phase voltage virtual value, the ω is command voltage waveform frequency to be output, describedFor command voltage waveform to be output First phase.

4. the modulator approach of submodule mixed type module Multilevel Inverters according to claim 3, it is characterised in that It is described by the carrier wave of each submodule described in every phase bridge arm compared with the modulating wave of each submodule, generation input Control signal to each submodule described in every phase bridge arm specifically includes step：

By each half-bridge of the carrier wave of each half-bridge submodule of the upper bridge arm of every phase bridge arm and the upper bridge arm per phase bridge arm The modulating wave of submodule is compared, the control letter of each half-bridge submodule of the upper bridge arm of generation input to every phase bridge arm Number；

By each half-bridge of the carrier wave of each half-bridge submodule of the lower bridge arm of every phase bridge arm and the lower bridge arm per phase bridge arm The modulating wave of submodule is compared, the control letter of each half-bridge submodule of the lower bridge arm of generation input to every phase bridge arm Number；

By each full-bridge of the carrier wave of each full-bridge submodule of the upper bridge arm of every phase bridge arm and the upper bridge arm per phase bridge arm First modulating wave and second modulating wave of submodule are compared respectively, the upper bridge of generation input to every phase bridge arm The first control signal and the second control signal of each full-bridge submodule of arm；

By each full-bridge of the carrier wave of each full-bridge submodule of the lower bridge arm of every phase bridge arm and the lower bridge arm per phase bridge arm The 3rd modulating wave of submodule and the 4th modulating wave are compared respectively, the lower bridge of generation input to every phase bridge arm The 3rd control signal and the 4th control signal of each full-bridge submodule of arm.

5. the modulator approach of submodule mixed type module Multilevel Inverters according to claim 1, it is characterised in that Described the step of determining the carrier frequency and carrier phase of each submodule in every phase bridge arm, includes：

Twice per the carrier frequency of half-bridge submodule described in phase bridge arm for the carrier frequency of the full-bridge submodule, per phase bridge The reference phase of the submodule of the upper bridge arm of arm be followed successively by 0,2 π/N, 2 × 2 π/N ..., (N-1) × 2 π/N, per phase bridge arm Lower bridge arm submodule reference phase be followed successively by 0,2 π/N, 2 × 2 π/N ..., (N-1) × 2 π/N, per phase bridge arm in The carrier phase of the full-bridge submodule is followed successively by the reference phase of the submodule divided by 2 adds π/4, described in phase bridge arm The carrier phase of half-bridge submodule is maintained the reference phase.

6. how electric the modulating system of a seed module mixed type module Multilevel Inverters, the submodule mixed type moduleization be The upper bridge arm of every phase bridge arm of flat current transformer includes N number of submodule connected with lower bridge arm, and N number of submodule includes M half-bridge Submodule and N-M full-bridge submodule, wherein, the N is positive integer, and the M is positive integer, and the N is more than the M, its It is characterised by,

First determining module, output order voltage waveform is often treated each other for basis, it is determined that each tune of submodule in per phase bridge arm Ripple processed, wherein, the modulating wave of the submodule includes the modulating wave of half-bridge submodule and the modulating wave of full-bridge submodule；

3rd determining module, the carrier frequency and the carrier phase for each submodule in the every phase bridge arm of basis, It is determined that in per phase bridge arm each submodule carrier wave；

Comparison module, for the modulating wave of the carrier wave of each submodule described in every phase bridge arm and each submodule to be carried out Compare, the control signal of generation input to each submodule described in every phase bridge arm；

Acquisition module, for according to each control signal, controlling per each submodule input or cut-out in phase bridge arm, obtaining respectively Per the output voltage waveforms of each submodule described in phase bridge arm；

Processing module, for the output voltage waveforms superposition for the submodule that will be put into every phase bridge arm, obtain the submodule and mix Every phase bridge arm output voltage waveforms of mould assembly modular multi-level converter.

7. the modulating system of submodule mixed type module Multilevel Inverters according to claim 6, it is characterised in that

First determining module, specifically for often treating each other output order voltage waveform to described and being translated, overturn and stretched At least one of conversion processing, or by it is described often treat each other output order voltage waveform be defined as it is described per phase bridge arm Neutron module Modulating wave, obtain it is described per phase bridge arm in each submodule modulating wave.

8. the modulating system of submodule mixed type module Multilevel Inverters according to claim 7, it is characterised in that First determining module includes：

First determining unit, for often treating each other output order voltage waveform to described and overturning, obtain the upper bridge per phase bridge arm The modulating wave of each half-bridge submodule of arm；

Second determining unit, for by it is described often treat each other output order voltage waveform be defined as every phase bridge arm lower bridge arm it is each The modulating wave of half-bridge submodule；

3rd determining unit, for often treating each other output order voltage waveform to described and being overturn and translated, obtain per phase bridge arm Upper bridge arm each full-bridge submodule the first modulating wave；

4th determining unit, for often treating each other output order voltage waveform to described and translating, obtain the upper bridge per phase bridge arm Second modulating wave of each full-bridge submodule of arm；

5th determining unit, for often treating each other output order voltage waveform to described and translating, obtain the lower bridge per phase bridge arm 3rd modulating wave of each full-bridge submodule of arm；

6th determining unit, for often treating each other output order voltage waveform to described and being overturn and translated, obtain per phase bridge arm Lower bridge arm each full-bridge submodule the 4th modulating wave；

9. the modulating system of submodule mixed type module Multilevel Inverters according to claim 8, it is characterised in that The comparison module includes：

First comparing unit, for by the carrier wave of each half-bridge submodule of the upper bridge arm of every phase bridge arm and upper bridge per phase bridge arm The modulating wave of each half-bridge submodule of arm is compared, and described each the half of the upper bridge arm of generation input to every phase bridge arm The control signal of bridge submodule；

Second comparing unit, for by the carrier wave of each half-bridge submodule of the lower bridge arm of every phase bridge arm and lower bridge per phase bridge arm The modulating wave of each half-bridge submodule of arm is compared, and described each the half of the lower bridge arm of generation input to every phase bridge arm The control signal of bridge submodule；

3rd comparing unit, for by the carrier wave of each full-bridge submodule of the upper bridge arm of every phase bridge arm and upper bridge per phase bridge arm First modulating wave and second modulating wave of each full-bridge submodule of arm are compared respectively, generation input To the first control signal and the second control signal of each full-bridge submodule of the upper bridge arm of every phase bridge arm；

4th comparing unit, for by the carrier wave of each full-bridge submodule of the lower bridge arm of every phase bridge arm and lower bridge per phase bridge arm The 3rd modulating wave and the 4th modulating wave of each full-bridge submodule of arm are compared respectively, generation input To the 3rd control signal and the 4th control signal of each full-bridge submodule of the lower bridge arm of every phase bridge arm.

10. the modulating system of submodule mixed type module Multilevel Inverters according to claim 6, its feature exist In, twice per the carrier frequency of half-bridge submodule described in phase bridge arm for the carrier frequency of the full-bridge submodule, per phase bridge The reference phase of the submodule of the upper bridge arm of arm be followed successively by 0,2 π/N, 2 × 2 π/N ..., (N-1) × 2 π/N, per phase bridge arm Lower bridge arm submodule reference phase be followed successively by 0,2 π/N, 2 × 2 π/N ..., (N-1) × 2 π/N, per phase bridge arm in The carrier phase of the full-bridge submodule is followed successively by the reference phase of the submodule divided by 2 adds π/4, described in phase bridge arm The carrier phase of half-bridge submodule is maintained the reference phase.