CN105356780A - Modulation method and system for modularized multi-level current converter with mixed sub modules - Google Patents

Modulation method and system for modularized multi-level current converter with mixed sub modules Download PDF

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CN105356780A
CN105356780A CN201510706087.9A CN201510706087A CN105356780A CN 105356780 A CN105356780 A CN 105356780A CN 201510706087 A CN201510706087 A CN 201510706087A CN 105356780 A CN105356780 A CN 105356780A
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brachium pontis
submodule
phase
modulating wave
full
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CN105356780B (en
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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
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China Southern Power Grid Co Ltd
Research Institute of Southern Power Grid Co Ltd
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China Southern Power Grid Co Ltd
Research Institute of Southern Power Grid Co Ltd
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Abstract

The invention relates to a modulation method and system for a modularized multi-level current converter with mixed sub modules. The modulation method comprises the steps of determining modulation wave of each sub module in each phase bridge arm according to each phase to-be-output instruction voltage waveform, wherein the modulation wave of each sub module comprises the modulation wave of a half-bridge sub module and the modulation wave of a full-bridge sub module; performing comparison between the carrier wave of each sub module and the modulation wave of each sub module in each phase bridge arm to generate control signals for controlling the input or cut-off of each sub module in each phase bridge arm separately; and performing output voltage waveform superimposition on the sub module input in each phase bridge arm to obtain the output voltage waveform of each phase bridge arm. The modulation wave of the half-bridge sub module is used for modulation with the carrier waver of the half-bridge sub module; the modulation wave of the full-bridge sub module is used for modulation with the carrier waver of the full-bridge sub module, so as to realize the accurate modulation on the carrier wave and the modulation wave of the mixed sub modules, therefore, the improvement of the output voltage waveform quality of the modularized current transformer with the mixed sub modules is facilitated.

Description

The modulator approach of submodule mixed type module Multilevel Inverters and system
Technical field
The present invention relates to electric field, particularly the modulator approach of a seed module mixed type module Multilevel Inverters and system.
Background technology
After the topological structure of modularization multilevel converter (MMC) is suggested to, adopts high voltage direct current transmission (HVDC) system of MMC to receive increasing concern, apply also more extensive.MMC-HVDC system adopts modular structure, every phase brachium pontis of existing MMC comprises brachium pontis and lower brachium pontis, every phase brachium pontis is connected in parallel on direct current network positive and negative end, upper brachium pontis and the lower brachium pontis of every phase include N number of submodule of connecting and the brachium pontis inductance of connecting with described submodule, and the brachium pontis inductance of the described upper brachium pontis of every phase and the brachium pontis inductance of described lower brachium pontis are connected in series.
MMC is widely used in DC transmission system, and DC side fault is difficult to avoid.Present stage several MMC-HVDC engineering put into operation, all adopt half-bridge submodule (Half-bridgesub-module, HBSM) as the basic submodule of MMC, the semi-bridge type MMC used in current Practical Project does not possess short trouble isolating power, but the semiconductor device that it adopts is few, the most economical.Adopt full-bridge submodule (Full-bridgesub-module, FBSM) bridge-type MMC is formed, full-bridge submodule compares half-bridge submodule, full-bridge submodule can pass through the shutoff limiting short-circuit current of IGBT (insulated gate bipolar transistor), but the quantity of IGBT and diode all turned over one times, with high costs.In conjunction with the advantage of half-bridge submodule and full-bridge submodule, propose submodule mixed type MMC, in the MMC of this structure, contain full-bridge submodule and half-bridge submodule, and full-bridge submodule quantity reaches certain proportion.
One of necessary condition that MMC normally works is rational modulation system, for pure semi-bridge type MMC or pure bridge-type MMC, conventional modulation system has the stacked (Phaseposition of carrier wave, PD), phase-shifting carrier wave (Phaseshiftedcarrier, PSC) and nearest level approach (Nearestlevelmodulation, NLM), by modulation make the output of MMC approach sine wave.Carrier wave is stacked to be superposed multiple PWM (pulse width modulation) ripple by different level, but adopts the stacked modulation system of carrier wave.Adopt phase-shifting carrier wave modulation system, be that out of phase for multiple carrier wave PWM ripple is stacked up, be used for approaching sine wave.Adopt nearest level modulation mode, by the output of program control submodule, thus generation staircase waveform approaches sine wave.But, for submodule mixed type MMC, original modulation system for pure bridge-type MMC device and pure semi-bridge type MMC is also inapplicable, because in submodule mixed type MMC topological structure, an existing full-bridge submodule of brachium pontis has again half-bridge submodule, this two seed module operating state is not identical with pattern, and original modulation system has when identical mode of operation based on each submodule to carry out work, during the original modulation system of such employing, the output voltage waveforms of submodule mixed type MMC can be caused of low quality.
Summary of the invention
Based on this, be necessary, for the second-rate problem of the voltage waveform adopting existing modulator approach to cause submodule mixed type module Multilevel Inverters to export, to provide modulator approach and the system of the submodule mixed type module Multilevel Inverters that can improve output voltage waveforms quality.
The modulator approach of one seed module mixed type module Multilevel Inverters, the upper brachium pontis of every phase brachium pontis of described submodule mixed type module Multilevel Inverters includes N number of submodule of connecting with lower brachium pontis, N number of submodule comprises M half-bridge submodule and N-M full-bridge submodule, wherein, described N is positive integer, described M is positive integer, and described N is greater than described M;
The modulator approach of described submodule mixed type module Multilevel Inverters comprises the steps:
According to often treating each other output order voltage waveform, determine the modulating wave of each submodule in every phase brachium pontis, wherein, the modulating wave of described submodule comprises the modulating wave of half-bridge submodule and the modulating wave of full-bridge submodule;
Determine carrier frequency and the carrier phase of each submodule in every phase brachium pontis;
According to described carrier frequency and the described carrier phase of each submodule in every phase brachium pontis, determine the carrier wave of each submodule in every phase brachium pontis;
The carrier wave of each submodule described in every phase brachium pontis and the modulating wave of described each submodule are compared, generates the control signal inputing to each submodule described in every phase brachium pontis;
According to each described control signal, control each submodule in every phase brachium pontis respectively and drop into or cut off, obtain the output voltage waveforms of each submodule described in every phase brachium pontis;
The output voltage waveforms of the submodule dropped in every phase brachium pontis is superposed, obtains every phase brachium pontis output voltage waveforms of described submodule mixed type module Multilevel Inverters.
The present invention also provides the modulating system of a seed module mixed type module Multilevel Inverters, the upper brachium pontis of every phase brachium pontis of described submodule mixed type module Multilevel Inverters includes N number of submodule of connecting with lower brachium pontis, N number of submodule comprises M half-bridge submodule and N-M full-bridge submodule, wherein, described N is positive integer, described M is positive integer, and described N is greater than described M;
The modulating system of described submodule mixed type module Multilevel Inverters comprises:
First determination module, often treat each other output order voltage waveform for basis, determine the modulating wave of each submodule in every phase brachium pontis, wherein, the modulating wave of described submodule comprises the modulating wave of half-bridge submodule and the modulating wave of full-bridge submodule;
Second determination module, for determining carrier frequency and the carrier phase of each submodule in every phase brachium pontis;
3rd determination module, for according to the described carrier frequency of each submodule in every phase brachium pontis and described carrier phase, determines the carrier wave of each submodule in every phase brachium pontis;
Comparison module, for by the carrier wave of each submodule described in every phase brachium pontis and described each submodule
Modulating wave compares, and generates the control signal inputing to each submodule described in every phase brachium pontis;
Acquisition module, for according to each described control signal, controls each submodule in every phase brachium pontis respectively and drops into or cut off, obtain the output voltage waveforms of each submodule described in every phase brachium pontis;
Processing module, the output voltage waveforms for the submodule will dropped in every phase brachium pontis superposes, and obtains every phase brachium pontis output voltage waveforms of described submodule mixed type module Multilevel Inverters.
The modulator approach of above-mentioned submodule mixed type module Multilevel Inverters and system, according to often treating each other output order voltage waveform, determine the modulating wave of each submodule in every phase brachium pontis, wherein, the modulating wave of described submodule comprises the modulating wave of half-bridge submodule and the modulating wave of full-bridge submodule, the carrier wave of each submodule described in every phase brachium pontis and the modulating wave of described each submodule are compared, generate the control signal inputing to each submodule described in every phase brachium pontis, according to each described control signal, control each submodule in every phase brachium pontis respectively to drop into or cut off, obtain the output voltage waveforms of each submodule described in every phase brachium pontis, the output voltage waveforms of the submodule dropped in every phase brachium pontis is superposed, obtain every phase brachium pontis output voltage waveforms of described submodule mixed type module Multilevel Inverters.Modulating wave due to the submodule determined comprises the modulating wave of half-bridge submodule and the modulating wave of full-bridge submodule, the modulating wave of half-bridge submodule is used for modulating with the carrier wave of half-bridge submodule, the modulating wave of full-bridge submodule is used for modulating with the carrier wave of full-bridge submodule, thus the accurate modulation realized mixed type submodule carrier wave and modulating wave, be conducive to the quality improving submodule mixed type module current transformer output voltage waveforms.
Accompanying drawing explanation
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 modulator approach of submodule mixed type module Multilevel Inverters of execution mode;
Fig. 5 is pure half-bridge module Multilevel Inverters and pure full-bridge modules Multilevel Inverters structural representation;
Fig. 6 is the sub-process figure of the modulator approach of the submodule mixed type module Multilevel Inverters of another kind of execution mode;
Fig. 7 is the sub-process figure of the modulator approach of the submodule mixed type module Multilevel Inverters of another kind of execution mode;
Fig. 8 is the sub-process figure of the modulator approach of the submodule mixed type module Multilevel Inverters of another kind of execution mode;
Fig. 9 is submodule mixed type module Multilevel Inverters phase-shifting carrier wave modulation schematic diagram;
Figure 10 is modulating wave and the carrier wave figure of the half-bridge submodule of upper and lower brachium pontis;
Figure 11 is modulating wave and the carrier wave figure of the full-bridge submodule of upper and lower brachium pontis;
Figure 12 is the PWM oscillogram that modulating wave and triangular carrier compare 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 modulating system of submodule mixed type module Multilevel Inverters of execution mode;
Figure 16 is the submodule figure of the modulating system of the submodule mixed type module Multilevel Inverters of another kind of execution mode;
Figure 17 is the submodule figure of the modulating system of the submodule mixed type module Multilevel Inverters of another kind of execution mode.
Embodiment
Refer to Fig. 1, the upper brachium pontis of every phase brachium pontis of submodule mixed type module Multilevel Inverters includes N number of submodule of connecting with lower brachium pontis, N number of submodule comprises M half-bridge submodule and N-M full-bridge submodule, wherein, described N is positive integer, described M is positive integer, and described N is greater than described M.
Refer to Fig. 2, half-bridge submodule comprises an IGBT pipe T1, 2nd IGBT pipe T2, first sustained diode 1, second sustained diode 2 and the first electric capacity C1, the collector electrode of the one IGBT pipe T1 is connected with one end of the first electric capacity C1, the other end of the first electric capacity C1 is connected with the emitter of the 2nd IGBT pipe T2, the positive pole of the first sustained diode 1 is connected with the emitter of an IGBT pipe T1, negative pole is connected with the collector electrode of an IGBT pipe T1, the collector electrode of the 2nd IGBT pipe T2 connects and is connected with the emitter of an IGBT pipe T1, the positive pole of the second sustained diode 2 is connected with the emitter of the 2nd IGBT pipe T2, negative pole is connected with the collector electrode of the 2nd IGBT pipe T2, the base stage of the one IGBT pipe T1 and the 2nd IGBT pipe T2 all receives the control signal that external equipment provides, by base stage reception control signal, the conducting of control IGBT pipe and closedown.One IGBT pipe T1 and the 2nd IGBT pipe T2 is conducting in turn.
Refer to Fig. 3, full-bridge submodule comprises the 3rd IGBT pipe T3, 4th IGBT pipe T4, 5th IGBT pipe T5, 6th IGBT pipe T6, 3rd sustained diode 3, 4th sustained diode 4, 5th sustained diode 5, 6th sustained diode 6 and the second electric capacity C2, the collector electrode of the 3rd IGBT pipe T3, the collector electrode of the 4th IGBT pipe T4 and one end of the second electric capacity C2 are connected, the emitter of the 3rd IGBT pipe T3 is connected with the collector electrode of the 5th IGBT pipe T5, the emitter of the 5th IGBT pipe T5, the emitter of the 6th IGBT pipe T6 and the other end of the second electric capacity C2 are connected, the emitter of the 4th IGBT pipe T4 is connected with the collector electrode of the 6th IGBT pipe T6, the positive pole of the 3rd sustained diode 3 is connected with the emitter of the 3rd IGBT pipe T3, negative pole is connected with the collector electrode of the 3rd IGBT pipe T3, the positive pole of the 4th sustained diode 4 is connected with the emitter of the 4th IGBT pipe D4, negative pole is connected with the collector electrode of the 4th IGBT pipe T4, the positive pole of the 5th sustained diode 5 is connected with the emitter of the 5th IGBT pipe T5, negative pole is connected with the collector electrode of the 5th IGBT pipe T5, the positive pole of the 6th sustained diode 6 is connected with the emitter of the 6th IGBT pipe T6, negative pole is connected with the collector electrode of the 6th IGBT pipe T6, 3rd IGBT pipe T3, 4th IGBT pipe T4, the base stage of the 5th IGBT pipe T5 and the 6th IGBT pipe T6 all receives the control signal that foreign currency equipment provides.3rd IGBT pipe T3 and the 5th IGBT pipe T5 is conducting in turn, and the 4th IGBT pipe T4 and the 6th IGBT pipe T6 is also conducting in turn.
By carrier wave and modulation wave modulation, produce the drive singal driving each submodule, the conducting of the IGBT pipe in driver module Multilevel Inverters Neutron module and closedown, reasonably control input and the excision of each phase submodule, and then control the quantity of the submodule effectively worked in every phase brachium pontis, the voltage waveform that the submodule of input exports is superposed, thus the interchange close to modulating wave obtaining modular multi-level converter exports the ac output voltage difference that different modulator approaches can make the output of modular multi-level converter.
Refer to Fig. 4, a kind of modulator approach of submodule mixed type module Multilevel Inverters of execution mode be provided,
S100: according to often treating each other output order voltage waveform, determines the modulating wave of each submodule in every phase brachium pontis.
Wherein, the modulating wave of submodule comprises the modulating wave of half-bridge submodule and the modulating wave of full-bridge submodule.By submodule mixed type module Multilevel Inverters, direct voltage is converted to alternating voltage to export, command voltage waveform to be output refers to the voltage waveform expecting to be exported by this submodule mixed type module Multilevel Inverters.Due to by carrier wave and modulation wave modulation, control input and the excision of submodule mixed type module Multilevel Inverters Neutron module, carry out superposing to the output voltage of the submodule dropped into and obtain the output voltage waveforms of submodule mixed type module Multilevel Inverters output close to modulating wave, thus can according to often treating each other output order voltage waveform, determine the modulating wave of each submodule in every phase brachium pontis, the output voltage waveforms of submodule mixed type module Multilevel Inverters can be made so more close to desired output waveform.
S200: carrier frequency and the carrier phase of determining each submodule in every phase brachium pontis.
Determine that the parameter of carrier wave comprises carrier frequency and carrier phase, thus need to select carrier frequency and carrier phase.
S300: according to carrier frequency and the carrier phase of each submodule in every phase brachium pontis, determine the carrier wave of each submodule in every phase brachium pontis.
After carrier frequency and carrier phase are determined, carrier wave is also determined thereupon.
S400: the carrier wave of each submodule in every phase brachium pontis and the modulating wave of each submodule are compared, generates the control signal inputing to each submodule in every phase brachium pontis.
By the comparison of carrier wave and modulating wave, produce the control signal driving each submodule, when the modulating wave of submodule is greater than the carrier wave of submodule, produce high ordinary mail number, when modulating wave is less than carrier wave, produce low ordinary mail number.
S500: according to each control signal, controls each submodule in every phase brachium pontis respectively and drops into or cut off, obtain the output voltage waveforms of each submodule in every phase brachium pontis.
By the comparison of carrier wave and modulating wave, produce the control signal driving each submodule, according to each control signal, control each submodule in every phase brachium pontis respectively and drop into or cut off.When the modulating wave of submodule is greater than the carrier wave of submodule, produce high ordinary mail number, the base stage that high ordinary mail number inputs to an IGBT pipe makes its conducting, and the base stage inputing to the 2nd IGBT pipe after number reversion of high ordinary mail makes it close.When modulating wave is less than carrier wave, produce low ordinary mail number, low ordinary mail number inputs to an IGBT pipe makes it close, and inputs to the 2nd IGBT pipe and make its conducting after number reversion of low ordinary mail.According to conducting and the situation of closedown of IGBT pipe, control submodule to drop into or cut off, namely the output voltage controlling submodule is identical with electric capacity both end voltage, represent that submodule drops into, the output voltage controlling submodule is 0, represent submodule excision, thus the output voltage waveforms of each submodule in every phase brachium pontis can be obtained.
S600: the output voltage waveforms of the submodule dropped in every phase brachium pontis is superposed, obtains every phase brachium pontis output voltage waveforms of submodule mixed type module Multilevel Inverters.
The modulator approach of above-mentioned submodule mixed type module Multilevel Inverters, according to often treating each other output order voltage waveform, determine the modulating wave of each submodule in every phase brachium pontis, wherein, the modulating wave of described submodule comprises the modulating wave of half-bridge submodule and the modulating wave of full-bridge submodule, the carrier wave of each submodule described in every phase brachium pontis and the modulating wave of described each submodule are compared, generate the control signal inputing to each submodule described in every phase brachium pontis, according to each described control signal, control each submodule in every phase brachium pontis respectively to drop into or cut off, obtain the output voltage waveforms of each submodule described in every phase brachium pontis, the output voltage waveforms of the submodule dropped in every phase brachium pontis is superposed, obtain every phase brachium pontis output voltage waveforms of described submodule mixed type module Multilevel Inverters.Modulating wave due to the submodule determined comprises the modulating wave of half-bridge submodule and the modulating wave of full-bridge submodule, the modulating wave of half-bridge submodule is used for modulating with the carrier wave of half-bridge submodule, the modulating wave of full-bridge submodule is used for modulating with the carrier wave of full-bridge submodule, thus the accurate modulation realized mixed type submodule carrier wave and modulating wave, be conducive to the quality improving submodule mixed type module current transformer output voltage waveforms.
Particularly, the modulator approach of above-mentioned submodule mixed type module Multilevel Inverters is applicable to the submodule mixed type module Multilevel Inverters comprising full-bridge submodule and half-bridge submodule two type submodule in brachium pontis, pure semi-bridge type modular multi-level converter and pure bridge-type modular multi-level converter can regard sensu lato submodule mixed type module Multilevel Inverters as, above-mentioned modulator approach be equally applicable to as shown in Figure 5 only containing the modular multi-level converter of half-bridge submodule or only containing the modular multi-level converter of full-bridge submodule, namely above-mentioned modulator approach is equally applicable to M and equals the pure bridge-type modular multi-level converter that the pure semi-bridge type modular multi-level converter of N or M equal 0.Fig. 5 (a) represents the pure semi-bridge type modular multi-level converter structure chart not having full-bridge submodel, and Fig. 5 (b) represents the pure bridge-type modular multi-level converter structure chart not having half-bridge submodel.
Referring to Fig. 6, wherein in an embodiment, according to often treating each other output order voltage waveform, determining that the modulating wave S100 of each submodule in every phase brachium pontis is specially:
S110: at least one process of often treating each other output order voltage waveform and carrying out in translation, upset and stretching conversion, or will often treat each other output order voltage waveform and be defined as the modulating wave of every phase brachium pontis Neutron module, obtain the modulating wave of each submodule in every phase brachium pontis.
Because command voltage waveform to be output refers to the voltage waveform expecting to be exported by this submodule mixed type module Multilevel Inverters, and submodule mixed type module Multilevel Inverters output voltage waveforms is close to modulating wave, thus treat output order voltage waveform and carry out conversion process, obtain the modulating wave of submodule, or be directly the modulating wave of submodule by command voltage waveform definition to be output, make submodule mixed type module Multilevel Inverters output voltage ripple close to command voltage waveform to be output, namely close to desired output waveform.
Refer to Fig. 7, wherein in an embodiment, to the described at least one process of often treating each other output order voltage waveform and carrying out in translation, upset and stretching conversion, or often treat each other described the modulating wave that output order voltage waveform is defined as every phase brachium pontis Neutron module, the modulating wave S110 obtaining each submodule in every phase brachium pontis specifically comprises step:
S1101: overturn often treating each other output order voltage waveform, obtains the modulating wave of each half-bridge submodule of the upper brachium pontis of every phase brachium pontis;
S1102: will often treat each other output order voltage waveform and be defined as the modulating wave of each half-bridge submodule of the lower brachium pontis of every phase brachium pontis;
S1103: overturn and translation often treating each other output order voltage waveform, obtains the first modulating wave of each full-bridge submodule of the upper brachium pontis of every phase brachium pontis;
S1104: carry out translation to often treating each other output order voltage waveform, obtains the second modulating wave of each full-bridge submodule of the upper brachium pontis of every phase brachium pontis;
S1105: carry out translation to often treating each other output order voltage waveform, obtains the 3rd modulating wave of each full-bridge submodule of the lower brachium pontis of every phase brachium pontis;
S1106: overturn and translation often treating each other output order voltage waveform, obtains the 4th modulating wave of each full-bridge submodule of the lower brachium pontis of every phase brachium pontis.
Wherein, the concrete formula obtaining the modulating wave of each half-bridge submodule of the upper brachium pontis of every phase brachium pontis is:
The concrete formula obtaining the modulating wave of each half-bridge submodule of the lower brachium pontis of every phase brachium pontis is:
The concrete formula obtaining the first modulating wave of each full-bridge submodule of the upper brachium pontis of every phase brachium pontis is:
The concrete formula obtaining the second modulating wave of each full-bridge submodule of the upper brachium pontis of every phase brachium pontis is:
The concrete formula of the 3rd modulating wave obtaining each full-bridge submodule of the lower brachium pontis of every phase brachium pontis is:
The concrete formula of the 4th modulating wave obtaining each full-bridge submodule of the lower brachium pontis of every phase brachium pontis is;
In formula, u ref_jfor jth treats each other output order voltage waveform, j gets A, B or C, represents A phase, B phase or C phase respectively, u half_j-for the modulating wave of the half-bridge submodule of the upper brachium pontis of jth phase, u half_j+for the modulating wave of the half-bridge submodule of the lower brachium pontis of jth phase, u full1_j-the first modulating wave of the full-bridge submodule of brachium pontis is gone up mutually, u for jth full2_j-the second modulating wave of the full-bridge submodule of brachium pontis is gone up mutually, u for jth full3_j+for jth descends the 3rd modulating wave of the full-bridge submodule of brachium pontis mutually, u full4_j+for jth descends the 4th modulating wave of the full-bridge submodule of brachium pontis mutually, M represents modulation depth, for phase voltage effective value, ω is command voltage waveform frequency to be output, for command voltage waveform first phase to be output.
Refer to Fig. 8, wherein in an embodiment, the carrier wave of each submodule in every phase brachium pontis and the modulating wave of each submodule compared, generate the control signal S400 inputing to each submodule in every phase brachium pontis and specifically comprise step:
S410: compared by the modulating wave of the carrier wave of each half-bridge submodule of the upper brachium pontis of every phase brachium pontis with each half-bridge submodule of the upper brachium pontis of every phase brachium pontis, generates the control signal inputing to each half-bridge submodule of the upper brachium pontis of every phase brachium pontis.
This control signal is inputed to each half-bridge submodule of the upper brachium pontis of every phase brachium pontis, control input and the excision of each half-bridge submodule of the upper brachium pontis of every phase brachium pontis.
S420: compared by the modulating wave of the carrier wave of each half-bridge submodule of the lower brachium pontis of every phase brachium pontis with each half-bridge submodule of the lower brachium pontis of every phase brachium pontis, generates the control signal inputing to each half-bridge submodule of the lower brachium pontis of every phase brachium pontis.
This control signal is inputed to each half-bridge submodule of the lower brachium pontis of every phase brachium pontis, control input and the excision of each half-bridge submodule of the lower brachium pontis of every phase brachium pontis.
S430: the first modulating wave of the carrier wave of each full-bridge submodule of the upper brachium pontis of every phase brachium pontis and each full-bridge submodule of the upper brachium pontis of every phase brachium pontis and the second modulating wave are compared respectively, generates the first control signal and the second control signal that input to each full-bridge submodule of the upper brachium pontis of every phase brachium pontis.
The first control signal produced controls conducting and the closedown of the 3rd IGBT pipe in the full-bridge submodule of upper brachium pontis and the 4th IGBT pipe, the second control signal produced controls conducting and the closedown of the 5th IGBT pipe in the full-bridge submodule of upper brachium pontis and the 6th IGBT pipe, thus realizes input and the excision of the full-bridge submodule controlling above brachium pontis.
S440: the 3rd modulating wave of the carrier wave of each full-bridge submodule of the lower brachium pontis of every phase brachium pontis and each full-bridge submodule of the lower brachium pontis of every phase brachium pontis and the 4th modulating wave are compared respectively, generates the 3rd control signal and the 4th control signal that input to each full-bridge submodule of the lower brachium pontis of every phase brachium pontis.
The 3rd control signal produced controls conducting and the closedown of the 3rd IGBT pipe in the full-bridge submodule of lower brachium pontis and the 4th IGBT pipe, the 4th control signal produced controls conducting and the closedown of the 5th IGBT pipe in the full-bridge submodule of lower brachium pontis and the 6th IGBT pipe, thus the input of the full-bridge submodule of brachium pontis and excision under realizing controlling.
Wherein in an embodiment, in every phase brachium pontis, the carrier frequency of half-bridge submodule is the twice of the carrier frequency of full-bridge submodule, the reference phase of the submodule of the upper brachium pontis of every phase brachium pontis is all 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 brachium pontis of every phase brachium pontis is all followed successively by 0, 2 π/N, 2 × 2 π/N, (N-1) × 2 π/N, the reference phase that in every phase brachium pontis, the carrier phase of full-bridge submodule is followed successively by submodule adds π/4 divided by 2, in every phase brachium pontis, the carrier phase of half-bridge submodule is maintained reference phase.
In order to make half-bridge submodule and the collaborative work of full-bridge submodule, the carrier frequency of half-bridge submodule is identical with the equivalent carrier frequency of full-bridge submodule, the carrier phase of half-bridge submodule is identical with the equivalent carrier phase of full-bridge submodule, it is consistent with the PWM waveform that modulating wave in Figure 12 and triangular carrier compare gained that carrier wave and the modulating wave of full-bridge submodule due to full-bridge submodule compare the PWM waveform obtained, can be used as the bridge of linking up full-bridge submodule and half-bridge submodule thus, the equivalent carrier frequency of full-bridge submodule is the twice of the carrier frequency of full submodule, thus the carrier frequency of half-bridge submodule is the twice of the carrier frequency of full-bridge submodule.Sine wave is approached as far as possible in order to make submodule mixed type module Multilevel Inverters output voltage waveforms, phase shift is carried out to carrier wave, the equivalent carrier phase of full-bridge submodule is that the carrier phase of full-bridge submodule is multiplied by 2 and deducts pi/2 again, the reference phase of the submodule of upper brachium pontis is all followed successively by 0, 2 π/N, 2 × 2 π/N, (N-1) × 2 π/N, the reference phase of the submodule of lower brachium pontis is all followed successively by 0, 2 π/N, 2 × 2 π/N, (N-1) × 2 π/N, the carrier phase of half-bridge submodule is maintained reference phase, the reference phase that the equivalent carrier phase of full-bridge submodule also maintains submodule is successively constant, according to the relation of the equivalent carrier phase of full-bridge submodule and the carrier phase of full-bridge submodule, the reference phase that the carrier phase of known full-bridge submodule is followed successively by submodule adds π/4 divided by 2.
Below specifically to implement to be illustrated the modulator approach of above-mentioned submodule mixed type module Multilevel Inverters.
Be described mutually with one of three-phase submodule mixed type module Multilevel Inverters in Fig. 1, namely the phase in A phase, B phase and C phase is analyzed, class can be pushed into other phase of current transformer, the phase-shifting carrier wave modulator approach of the submodule mixed type module Multilevel Inverters utilizing the present embodiment to provide carries out the schematic diagram modulated as shown in Figure 9.Main devices has wave converter, triangular carrier generator and comparator, wave converter is connected with comparator, and triangular carrier generator is connected with comparator, and wave converter produces modulating wave, triangular carrier generator produces carrier wave, and comparator is used for comparing modulating wave and carrier wave.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 triangular carrier sequence occurs and main circuit part, and main circuit part mainly realizes output voltage waveforms.Modulating wave and carrier wave are compared, generate the control signal of IGBT in submodule, wherein, the half-bridge submodule IGBT control signal of lower brachium pontis compares generation by the carrier wave of the modulating wave of the half-bridge submodule of lower brachium pontis as shown in Figure 10 and the half-bridge submodule of lower brachium pontis, the half-bridge submodule IGBT control signal of upper brachium pontis is produced by the carrier wave of the modulating wave of the half-bridge submodule of the upper brachium pontis in Figure 10 and the half-bridge submodule of upper brachium pontis and compares generation, the full-bridge submodule IGBT control signal of lower brachium pontis is comparatively produced by the modulating wave of full-bridge submodule of lower brachium pontis as shown in figure 11 and the carrier wave ratio of the full-bridge submodule of lower brachium pontis, the full-bridge submodule IGBT control signal of upper brachium pontis compares generation by the carrier wave of the modulating wave of the full-bridge submodule of the upper brachium pontis in Figure 11 and the full-bridge submodule of upper brachium pontis.
First the modulating wave of half-bridge submodule and full-bridge submodule is determined, the modulating wave of half-bridge submodule and full-bridge submodule obtains by least one process treated output waveform command voltage waveform and carry out in translation, upset or stretching conversion, or be the modulating wave of submodule by waveform command voltage waveform definition to be output, thus obtain the modulating wave of submodule, suppose the instructional waveform voltage waveform u that jth is mutually to be output ref_jfor:
Wherein, j gets A, B or C, represents A phase, B phase or C phase respectively, u half_j-for the modulating wave of the half-bridge submodule of the upper brachium pontis of jth phase, M represents modulation depth, for phase voltage effective value, ω is command voltage waveform frequency to be output, for command voltage waveform first phase to be output.Modulating wave parameter and modulation depth are determined according to current transformer control algolithm.
The half-bridge submodule modulating wave u of brachium pontis and lower brachium pontis in generation half_j-and u half_j+, concrete formula is as follows:
Namely the waveform often descending brachium pontis to export mutually is and u ref_jthe sine wave of homophase, the waveform often going up brachium pontis output is mutually and u ref_janti-phase sine wave.Namely utilize stretching conversion and turning-over changed, also can generate half-bridge submodule modulating wave.
Regeneration full-bridge submodule modulating wave.Wherein, determine that the concrete formula of the first modulating wave of the full-bridge submodule of the upper brachium pontis of every phase is:
Determine that the concrete formula of the second modulating wave of the full-bridge submodule of the upper brachium pontis of every phase is:
Determine that the concrete formula of the 3rd modulating wave of the full-bridge submodule of the lower brachium pontis of every phase is:
Determine that the concrete formula of the 4th modulating wave of the full-bridge submodule of the lower brachium pontis of every phase is;
Equally, utilize stretch, translation and turning-over changed, also can obtain this four waveforms.Please refer to full-bridge submodule schematic diagram in Fig. 3.U full3_j+with u full4_j+brachium pontis full-bridge submodule under corresponding converter, u full3_j+the 3rd IGBT pipe T3 in corresponding lower brachium pontis in full-bridge submodule and the 4th IGBT pipe T4, u full4_j+correspondence descends the 5th IGBT pipe T5 and the 6th IGBT pipe T6 of full-bridge submodule in brachium pontis.U full1_j-and u full2_j-brachium pontis full-bridge submodule on corresponding converter, u full1_j-the 3rd IGBT pipe T3 in correspondence in brachium pontis in full-bridge submodule and the 4th IGBT pipe T4, u full2_j-5th IGBT pipe T5 of full-bridge submodule and the 6th IGBT pipe T6 in brachium pontis in correspondence.
Then the triangular carrier C that in upper brachium pontis in every phase brachium pontis and lower brachium pontis, each submodule is corresponding is determined 1, C 2..., C i..., C n.C 1represent the 1st triangular carrier that submodule is corresponding, C 2represent the 2nd triangular carrier that submodule is corresponding, C irepresent the triangular carrier that i-th submodule is corresponding, C nrepresenting the triangular carrier that N number of submodule is corresponding, determine triangular carrier, mainly determine two parameters, is frequency and the phase place of triangular carrier respectively.If all full-bridge submodule triangular carrier operating frequencies are k f, the operating frequency of all half-bridge submodule triangular carriers is k h, triangular carrier C 1, C 2..., C i..., C nphase place be respectively θ 1, θ 2..., θ i..., θ n, θ 1represent the phase place of the 1st triangular carrier that submodule is corresponding, θ 2represent the phase place of the 2nd triangular carrier that submodule is corresponding, θ irepresent the phase place of the triangular carrier that i-th submodule is corresponding, θ nrepresent the phase place of the triangular carrier that N number of submodule is corresponding, the bridge arm voltage generated for making modulation approaches sine wave as far as possible, therefore need to carry out phase shift to carrier wave, the reference phase that in upper brachium pontis and lower brachium pontis, each submodule is corresponding is respectively 0,2 π/N, 2 × 2 π/N ..., (i-1) × 2 π/N,, (N-1) × 2 π/N.
But concerning full-bridge submodule, triangular carrier and modulating wave u full1_j-, u full2_j-, u full3_j+and u full4_j+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 the PWM waveform modulated.The PWM waveform gone out for the modulating wave and carrier modulation that make full-bridge submodule can and the PWM waveform collaborative work that modulates of the carrier wave of half-bridge submodule and modulating wave, need to process the carrier wave of full-bridge submodule.
It is consistent with the PWM waveform that modulating wave in Figure 12 and triangular carrier compare gained that full-bridge submodule carrier wave and full-bridge submodule modulating wave compare the PWM waveform obtained, and can be used as the bridge of linking up full-bridge submodule and half-bridge submodule thus.In fact, in Figure 12, waveform is that in Figure 11, the carrier wave of full-bridge submodule in Figure 12, by abscissa axis doubling gained, is called equivalent carrier wave, is designated as C by corresponding waveform 1', C 2' ..., C i' ..., C ' n.
Therefore, for making half-bridge submodule and the collaborative work of full-bridge submodule, the triangular carrier of half-bridge submodule and full-bridge submodule equivalence carrier wave same frequency, and reference phase is followed successively by 0,2 π/N, 2 × 2 π/N ... (i-1) × 2 π/N ..., (N-1) × 2 π/N.Equivalence carrier frequency is carrier frequency 2 times, so full-bridge submodule triangular carrier frequency will be made identical with half-bridge submodule triangular carrier frequency, should meet k h=2k f, k hfor the carrier frequency of half-bridge submodule, k ffor the carrier frequency of full-bridge submodule.
Pass between full-bridge submodule carrier wave and equivalent carrier wave is:
θ i ′ = - π 2 + 2 θ i .
Thus, half-bridge submodule carrier wave and full-bridge submodule equivalence carrier phase is made to be respectively 0,2 π/N, 2 × 2 π/N ..., (i-1) × 2 π/N ..., (N-1) × 2 π/N, is designated as θ by this sequence phase i', θ i' representing i-th sub-full-bridge submodule equivalence carrier phase, i is more than or equal to 0, and is less than or equal to N, represents full-bridge submodule equivalent phase, to full-bridge submodule, obtains actual phase θ according to above formula backstepping i, i.e. the phase place of the triangular carrier that i-th submodule is corresponding, using the phase place of actual phase as full-bridge submodule triangular carrier.
After determining half-bridge submodule modulating wave, full-bridge submodule modulating wave, half-bridge submodule triangular wave, full-bridge submodule triangular carrier, can modulate, produce the control signal controlling each submodule, control input and the excision of submodule, the output voltage waveforms of submodule is superposed, obtains the output voltage waveforms of submodule mixed type module current transformer.
As Figure 13, each submodule output voltage waveforms is PWM ripple, each PWM ripple modulated owing to being equivalent to same modulating wave, so these PWM ripple first-harmonics are identical, but due to modulate by the carrier wave of out of phase cause there are differences between each PWM ripple of modulating, final bridge arm voltage is the superposition of the PWM ripple that these there are differences, and as shown in figure 14, the bridge arm voltage obtained after superposition approaches sine wave.
The present invention also provides a kind of modulating system of submodule mixed type module Multilevel Inverters of execution mode, wherein, the upper brachium pontis of every phase of submodule mixed type module Multilevel Inverters includes N number of submodule of connecting with lower brachium pontis, and N number of submodule comprises M half-bridge submodule and N-M full-bridge submodule.
Refer to Figure 15, the modulating system of above-mentioned submodule mixed type module Multilevel Inverters comprises:
First determination module 100, for according to often treating each other output order voltage waveform, determines the modulating wave of each submodule in every phase brachium pontis.
Wherein, the modulating wave of submodule comprises the modulating wave of half-bridge submodule and the modulating wave of full-bridge submodule.By submodule mixed type module Multilevel Inverters, direct voltage is converted to alternating voltage to export, command voltage waveform to be output refers to the voltage waveform expecting to be exported by this submodule mixed type module Multilevel Inverters.Due to by carrier wave and modulation wave modulation, control input and the excision of submodule mixed type module Multilevel Inverters Neutron module, carry out superposing to the output voltage of the submodule dropped into and obtain the output voltage waveforms of submodule mixed type module Multilevel Inverters output close to modulating wave, thus can according to often treating each other output order voltage waveform, determine the modulating wave of each submodule in every phase brachium pontis, the output voltage waveforms of submodule mixed type module Multilevel Inverters can be made so more close to desired output waveform.
Second determination module 200, for determining carrier frequency and the carrier phase of each submodule in every phase brachium pontis.
Determine that the parameter of carrier wave comprises carrier frequency and carrier phase, thus need to select carrier frequency and carrier phase.
3rd determination module 300, for according to the described carrier frequency of each submodule in every phase brachium pontis and described carrier phase, determines the carrier wave of each submodule in every phase brachium pontis.
After carrier frequency and carrier phase are determined, carrier wave is also determined thereupon.
Comparison module 400, for the carrier wave of each submodule described in every phase brachium pontis and the modulating wave of described each submodule being compared, generates the control signal inputing to each submodule described in every phase brachium pontis.
By the comparison of carrier wave and modulating wave, produce the control signal driving each submodule, when the modulating wave of submodule is greater than the carrier wave of submodule, produce high ordinary mail number, when modulating wave is less than carrier wave, produce low ordinary mail number.
Acquisition module 500, for according to each described control signal, controls each submodule in every phase brachium pontis respectively and drops into or cut off, obtain the output voltage waveforms of each submodule described in every phase brachium pontis.
By the comparison of carrier wave and modulating wave, produce the control signal driving each submodule, according to each control signal, control each submodule in every phase brachium pontis respectively and drop into or cut off.When the modulating wave of submodule is greater than the carrier wave of submodule, produce high ordinary mail number, the base stage that high ordinary mail number inputs to an IGBT pipe makes its conducting, and the base stage inputing to the 2nd IGBT pipe after number reversion of high ordinary mail makes it close.When modulating wave is less than carrier wave, produce low ordinary mail number, low ordinary mail number inputs to an IGBT pipe makes it close, and inputs to the 2nd IGBT pipe and make its conducting after number reversion of low ordinary mail.According to conducting and the situation of closedown of IGBT pipe, control submodule to drop into or cut off, namely the output voltage controlling submodule is identical with electric capacity both end voltage, represent that submodule drops into, the output voltage controlling submodule is 0, represent submodule excision, thus the output voltage waveforms of each submodule in every phase brachium pontis can be obtained.
Processing module 600, the output voltage waveforms for the submodule will dropped in every phase brachium pontis superposes, and obtains every phase brachium pontis output voltage waveforms of described submodule 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 waveform, determine the modulating wave of each submodule in every phase brachium pontis, wherein, the modulating wave of described submodule comprises the modulating wave of half-bridge submodule and the modulating wave of full-bridge submodule, the carrier wave of each submodule described in every phase brachium pontis and the modulating wave of described each submodule are compared, generate the control signal inputing to each submodule described in every phase brachium pontis, according to each described control signal, control each submodule in every phase brachium pontis respectively to drop into or cut off, obtain the output voltage waveforms of each submodule described in every phase brachium pontis, the output voltage waveforms of the submodule dropped in every phase brachium pontis is superposed, obtain every phase brachium pontis output voltage waveforms of described submodule mixed type module Multilevel Inverters.Modulating wave due to the submodule determined comprises the modulating wave of half-bridge submodule and the modulating wave of full-bridge submodule, the modulating wave of half-bridge submodule is used for modulating with the carrier wave of half-bridge submodule, the modulating wave of full-bridge submodule is used for modulating with the carrier wave of full-bridge submodule, thus the accurate modulation realized mixed type submodule carrier wave and modulating wave, be conducive to the quality improving submodule mixed type module current transformer output voltage waveforms.
Particularly, the modulating system of above-mentioned submodule mixed type module Multilevel Inverters is applicable to the submodule mixed type module Multilevel Inverters comprising full-bridge submodule and half-bridge submodule two type submodule in brachium pontis, pure semi-bridge type modular multi-level converter and pure bridge-type modular multi-level converter can regard sensu lato submodule mixed type module Multilevel Inverters as, above-mentioned modulating system be equally applicable to as shown in Figure 5 only containing the modular multi-level converter of half-bridge submodule or only containing the modular multi-level converter of full-bridge submodule.Fig. 5 (a) represents the pure semi-bridge type modular multi-level converter structure chart not having full-bridge submodel, and Fig. 5 (b) represents the pure bridge-type modular multi-level converter structure chart not having half-bridge submodel.
Wherein in an embodiment, first determination module 100, specifically for the described at least one process of often treating each other output order voltage waveform and carrying out in translation, upset and stretching conversion, or often treat each other described the modulating wave that output order voltage waveform is defined as every phase brachium pontis Neutron module, obtain the modulating wave of each submodule in every phase brachium pontis.
Because command voltage waveform to be output refers to the voltage waveform expecting to be exported by this submodule mixed type module Multilevel Inverters, and submodule mixed type module Multilevel Inverters output voltage waveforms is close to modulating wave, thus treat output order voltage waveform and carry out conversion process, obtain the modulating wave of submodule, or be directly the modulating wave of submodule by command voltage waveform definition to be output, make submodule mixed type module Multilevel Inverters output voltage ripple close to command voltage waveform to be output, namely close to desired output waveform.
Refer to Figure 16, wherein in an embodiment, the first determination module 100 comprises:
First determining unit 110, for overturning often treating each other output order voltage waveform, obtains the modulating wave of each half-bridge submodule of the upper brachium pontis of every phase brachium pontis.
Second determining unit 120, for will often treat each other output order voltage waveform and be defined as the modulating wave of each half-bridge submodule of the lower brachium pontis of every phase brachium pontis.
3rd determining unit 130, for overturning and translation often treating each other output order voltage waveform, obtains the first modulating wave of each full-bridge submodule of the upper brachium pontis of every phase brachium pontis.
4th determining unit 140, for carrying out translation to often treating each other output order voltage waveform, obtains the second modulating wave of each full-bridge submodule of the upper brachium pontis of every phase brachium pontis.
5th determining unit 150, for carrying out translation to often treating each other output order voltage waveform, obtains the 3rd modulating wave of each full-bridge submodule of the lower brachium pontis of every phase brachium pontis.
6th determining unit 160, for overturning and translation often treating each other output order voltage waveform, obtains the 4th modulating wave of each full-bridge submodule of the lower brachium pontis of every phase brachium pontis.
Wherein, the concrete formula obtaining the modulating wave of each half-bridge submodule of the upper brachium pontis of every phase brachium pontis is:
The concrete formula obtaining the modulating wave of each half-bridge submodule of the lower brachium pontis of every phase brachium pontis is:
The concrete formula obtaining the first modulating wave of each full-bridge submodule of the upper brachium pontis of every phase brachium pontis is:
The concrete formula obtaining the second modulating wave of each full-bridge submodule of the upper brachium pontis of every phase brachium pontis is:
The concrete formula of the 3rd modulating wave obtaining each full-bridge submodule of the lower brachium pontis of every phase brachium pontis is:
The concrete formula of the 4th modulating wave obtaining each full-bridge submodule of the lower brachium pontis of every phase brachium pontis is;
In formula, u ref_jfor jth treats each other output order voltage waveform, j gets A, B or C, represents A phase, B phase or C phase respectively, u half_j-for the modulating wave of the half-bridge submodule of the upper brachium pontis of jth phase, u half_j+for the modulating wave of the half-bridge submodule of the lower brachium pontis of jth phase, u full1_j-the first modulating wave of the full-bridge submodule of brachium pontis is gone up mutually, u for jth full2_j-the second modulating wave of the full-bridge submodule of brachium pontis is gone up mutually, u for jth full3_j+for jth descends the 3rd modulating wave of the full-bridge submodule of brachium pontis mutually, u full4_j+for jth descends the 4th modulating wave of the full-bridge submodule of brachium pontis mutually, M represents modulation depth, for phase voltage effective value, ω is command voltage waveform frequency to be output, for command voltage waveform first phase to be output.
Refer to Figure 17, wherein in an embodiment, comparison module 400 comprises:
First comparing unit 410, compare for the modulating wave of the carrier wave of each half-bridge submodule of the upper brachium pontis by every phase brachium pontis with each half-bridge submodule of the upper brachium pontis of every phase brachium pontis, generate the control signal inputing to each half-bridge submodule of the upper brachium pontis of every phase brachium pontis.
This control signal is inputed to each half-bridge submodule of the upper brachium pontis of every phase brachium pontis, control input and the excision of each half-bridge submodule of the upper brachium pontis of every phase brachium pontis.
Second comparing unit 420, compare for the modulating wave of the carrier wave of each half-bridge submodule of the lower brachium pontis by every phase brachium pontis with each half-bridge submodule of the lower brachium pontis of every phase brachium pontis, generate the control signal inputing to each half-bridge submodule of the lower brachium pontis of every phase brachium pontis.
This control signal is inputed to each half-bridge submodule of the lower brachium pontis of every phase brachium pontis, control input and the excision of each half-bridge submodule of the lower brachium pontis of every phase brachium pontis.
3rd comparing unit 430, compare respectively for the first modulating wave of the carrier wave of each full-bridge submodule of the upper brachium pontis by every phase brachium pontis and each full-bridge submodule of the upper brachium pontis of every phase brachium pontis and the second modulating wave, generate the first control signal and the second control signal that input to each full-bridge submodule of the upper brachium pontis of every phase brachium pontis.
The first control signal produced controls conducting and the closedown of the 3rd IGBT pipe in the full-bridge submodule of upper brachium pontis and the 4th IGBT pipe, the second control signal produced controls conducting and the closedown of the 5th IGBT pipe in the full-bridge submodule of upper brachium pontis and the 6th IGBT pipe, thus realizes input and the excision of the full-bridge submodule controlling above brachium pontis.
4th comparing unit 440, compare respectively for the 3rd modulating wave of the carrier wave of each full-bridge submodule of the lower brachium pontis by every phase brachium pontis and each full-bridge submodule of the lower brachium pontis of every phase brachium pontis and the 4th modulating wave, generate the 3rd control signal and the 4th control signal that input to each full-bridge submodule of the lower brachium pontis of every phase brachium pontis.
The 3rd control signal produced controls conducting and the closedown of the 3rd IGBT pipe in the full-bridge submodule of lower brachium pontis and the 4th IGBT pipe, the 4th control signal produced controls conducting and the closedown of the 5th IGBT pipe in the full-bridge submodule of lower brachium pontis and the 6th IGBT pipe, thus the input of the full-bridge submodule of brachium pontis and excision under realizing controlling.
Wherein in an embodiment, in every phase brachium pontis, the carrier frequency of half-bridge submodule is the twice of the carrier frequency of full-bridge submodule, the reference phase of the submodule of the upper brachium pontis of every phase brachium pontis is all 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 brachium pontis of every phase brachium pontis is all followed successively by 0, 2 π/N, 2 × 2 π/N, (N-1) × 2 π/N, the reference phase that in every phase brachium pontis, the carrier phase of full-bridge submodule is followed successively by submodule adds π/4 divided by 2, in every phase brachium pontis, the carrier phase of half-bridge submodule is maintained reference phase.
In order to make half-bridge submodule and the collaborative work of full-bridge submodule, the carrier frequency of half-bridge submodule is identical with the equivalent carrier frequency of full-bridge submodule, the carrier phase of half-bridge submodule is identical with the equivalent carrier phase of full-bridge submodule, it is consistent with the PWM waveform that modulating wave in Figure 12 and triangular carrier compare gained that carrier wave and the modulating wave of full-bridge submodule due to full-bridge submodule compare the PWM waveform obtained, can be used as the bridge of linking up full-bridge submodule and half-bridge submodule thus, the equivalent carrier frequency of full-bridge submodule is the twice of the carrier frequency of full submodule, thus the carrier frequency of half-bridge submodule is the twice of the carrier frequency of full-bridge submodule.Sine wave is approached as far as possible in order to make submodule mixed type module Multilevel Inverters output voltage waveforms, phase shift is carried out to carrier wave, the equivalent carrier phase of full-bridge submodule is that the carrier phase of full-bridge submodule is multiplied by 2 and deducts pi/2 again, the reference phase of the submodule of the submodule of upper brachium pontis is all followed successively by 0, 2 π/N, 2 × 2 π/N, (N-1) × 2 π/N, the reference phase of the submodule of lower brachium pontis is all followed successively by 0, 2 π/N, 2 × 2 π/N, (N-1) × 2 π/N, the carrier phase of half-bridge submodule is maintained reference phase, the reference phase that the equivalent carrier phase of full-bridge submodule also maintains submodule is successively constant, according to the relation of the equivalent carrier phase of full-bridge submodule and the carrier phase of full-bridge submodule, the reference phase that the carrier phase of known full-bridge submodule is followed successively by submodule adds π/4 divided by 2.
Above embodiment only have expressed several execution mode of the present invention, and it describes comparatively concrete and detailed, but can not therefore be construed as limiting the scope of the patent.It should be pointed out that for the person of ordinary skill of the art, without departing from the inventive concept of the premise, can also make some distortion and improvement, these all belong to protection scope of the present invention.Therefore, the protection range of patent of the present invention should be as the criterion with claims.

Claims (10)

1. the modulator approach of a seed module mixed type module Multilevel Inverters, the upper brachium pontis of every phase brachium pontis of described submodule mixed type module Multilevel Inverters includes N number of submodule of connecting with lower brachium pontis, N number of submodule comprises M half-bridge submodule and N-M full-bridge submodule, wherein, described N is positive integer, and described M is positive integer, and described N is greater than described M, it is characterized in that
The modulator approach of described submodule mixed type module Multilevel Inverters comprises the steps:
According to often treating each other output order voltage waveform, determine the modulating wave of each submodule in every phase brachium pontis, wherein, the modulating wave of described submodule comprises the modulating wave of half-bridge submodule and the modulating wave of full-bridge submodule;
Determine carrier frequency and the carrier phase of each submodule in every phase brachium pontis;
According to described carrier frequency and the described carrier phase of each submodule in every phase brachium pontis, determine the carrier wave of each submodule in every phase brachium pontis;
The carrier wave of each submodule described in every phase brachium pontis and the modulating wave of described each submodule are compared, generates the control signal inputing to each submodule described in every phase brachium pontis;
According to each described control signal, control each submodule in every phase brachium pontis respectively and drop into or cut off, obtain the output voltage waveforms of each submodule described in every phase brachium pontis;
The output voltage waveforms of the submodule dropped in every phase brachium pontis is superposed, obtains every phase brachium pontis output voltage waveforms of described submodule mixed type module Multilevel Inverters.
2. the modulator approach of submodule mixed type module Multilevel Inverters according to claim 1, it is characterized in that, described basis often treats each other output order voltage waveform, determines that the modulating wave of each submodule in every phase brachium pontis is specially:
To the described at least one process of often treating each other output order voltage waveform and carrying out in translation, upset and stretching conversion, or often treat each other described the modulating wave that output order voltage waveform is defined as described every phase brachium pontis Neutron module, obtain the modulating wave of each submodule in described every phase brachium pontis.
3. the modulator approach of submodule mixed type module Multilevel Inverters according to claim 2, it is characterized in that, described to the described at least one process of often treating each other output order voltage waveform and carrying out in translation, upset and stretching conversion, or often treat each other described the modulating wave that output order voltage waveform is defined as described every phase brachium pontis Neutron module, the step obtaining the modulating wave of each submodule in described every phase brachium pontis comprises:
Often treat each other output order voltage waveform overturn described, obtain the modulating wave of each half-bridge submodule of the upper brachium pontis of every phase brachium pontis;
The modulating wave that output order voltage waveform is defined as each half-bridge submodule of the lower brachium pontis of every phase brachium pontis is often treated each other by described;
Often treat each other output order voltage waveform overturn and translation described, obtain the first modulating wave of each full-bridge submodule of the upper brachium pontis of every phase brachium pontis;
Often treat each other output order voltage waveform carry out translation to described, obtain the second modulating wave of each full-bridge submodule of the upper brachium pontis of every phase brachium pontis;
Often treat each other output order voltage waveform carry out translation to described, obtain the 3rd modulating wave of each full-bridge submodule of the lower brachium pontis of every phase brachium pontis;
Often treat each other output order voltage waveform overturn and translation described, obtain the 4th modulating wave of each full-bridge submodule of the lower brachium pontis of every phase brachium pontis;
Wherein, the concrete formula obtaining the modulating wave of each half-bridge submodule of the upper brachium pontis of described every phase brachium pontis is:
The concrete formula obtaining the modulating wave of each half-bridge submodule of the lower brachium pontis of described every phase brachium pontis is:
The concrete formula obtaining the first modulating wave of each full-bridge submodule of the upper brachium pontis of described every phase brachium pontis is:
The concrete formula obtaining the second modulating wave of each full-bridge submodule of the upper brachium pontis of described every phase brachium pontis is:
The concrete formula of the 3rd modulating wave obtaining each full-bridge submodule of the lower brachium pontis of described every phase brachium pontis is:
The concrete formula of the 4th modulating wave obtaining each full-bridge submodule of the lower brachium pontis of described every phase brachium pontis is;
In formula, described u ref_jfor jth treats each other output order voltage waveform, described j gets A, B or C, represents A phase, B phase or C phase respectively, described u half_j-for the modulating wave of the half-bridge submodule of the upper brachium pontis of jth phase, described u half_j+for the modulating wave of the half-bridge submodule of the lower brachium pontis of jth phase, described u full1_j-the first modulating wave of the full-bridge submodule of brachium pontis is gone up mutually, described u for jth full2_j-the second modulating wave of the full-bridge submodule of brachium pontis is gone up mutually, described u for jth full3_j+for jth descends the 3rd modulating wave of the full-bridge submodule of brachium pontis mutually, described u full4_j+for jth descends the 4th modulating wave of the full-bridge submodule of brachium pontis mutually, described M represents modulation depth, described in for phase voltage effective value, described ω is command voltage waveform frequency to be output, described in for command voltage waveform first phase to be output.
4. the modulator approach of submodule mixed type module Multilevel Inverters according to claim 3, it is characterized in that, described the carrier wave of each submodule described in every phase brachium pontis and the modulating wave of described each submodule to be compared, generate the control signal inputing to each submodule described in every phase brachium pontis and specifically comprise step:
The modulating wave of the carrier wave of each half-bridge submodule of the upper brachium pontis of every phase brachium pontis with described each half-bridge submodule of the upper brachium pontis of every phase brachium pontis is compared, generates the control signal inputing to described each half-bridge submodule of the upper brachium pontis of every phase brachium pontis;
The modulating wave of the carrier wave of each half-bridge submodule of the lower brachium pontis of every phase brachium pontis with described each half-bridge submodule of the lower brachium pontis of every phase brachium pontis is compared, generates the control signal inputing to described each half-bridge submodule of the lower brachium pontis of every phase brachium pontis;
Described first modulating wave of the carrier wave of each full-bridge submodule of the upper brachium pontis of every phase brachium pontis and described each full-bridge submodule of the upper brachium pontis of every phase brachium pontis and described second modulating wave are compared respectively, generates the first control signal and the second control signal that input to described each full-bridge submodule of the upper brachium pontis of every phase brachium pontis;
Described 3rd modulating wave of the carrier wave of each full-bridge submodule of the lower brachium pontis of every phase brachium pontis and described each full-bridge submodule of the lower brachium pontis of every phase brachium pontis and described 4th modulating wave are compared respectively, generates the 3rd control signal and the 4th control signal that input to described each full-bridge submodule of the lower brachium pontis of every phase brachium pontis.
5. the modulator approach of submodule mixed type module Multilevel Inverters according to claim 1, is characterized in that, describedly determines that in every phase brachium pontis, the carrier frequency of each submodule and the step of carrier phase comprise:
The carrier frequency of half-bridge submodule described in every phase brachium pontis is the twice of the carrier frequency of described full-bridge submodule, the reference phase of the submodule of the upper brachium pontis of every phase brachium pontis is all 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 brachium pontis of every phase brachium pontis is all followed successively by 0, 2 π/N, 2 × 2 π/N, (N-1) × 2 π/N, the reference phase that the carrier phase of full-bridge submodule described in every phase brachium pontis is followed successively by described submodule adds π/4 divided by 2, described in every phase brachium pontis, the carrier phase of half-bridge submodule is maintained described reference phase.
6. the modulating system of a seed module mixed type module Multilevel Inverters, the upper brachium pontis of every phase brachium pontis of described submodule mixed type module Multilevel Inverters includes N number of submodule of connecting with lower brachium pontis, N number of submodule comprises M half-bridge submodule and N-M full-bridge submodule, wherein, described N is positive integer, and described M is positive integer, and described N is greater than described M, it is characterized in that
The modulating system of described submodule mixed type module Multilevel Inverters comprises:
First determination module, often treat each other output order voltage waveform for basis, determine the modulating wave of each submodule in every phase brachium pontis, wherein, the modulating wave of described submodule comprises the modulating wave of half-bridge submodule and the modulating wave of full-bridge submodule;
Second determination module, for determining carrier frequency and the carrier phase of each submodule in every phase brachium pontis;
3rd determination module, for according to the described carrier frequency of each submodule in every phase brachium pontis and described carrier phase, determines the carrier wave of each submodule in every phase brachium pontis;
Comparison module, for the carrier wave of each submodule described in every phase brachium pontis and the modulating wave of described each submodule being compared, generates the control signal inputing to each submodule described in every phase brachium pontis;
Acquisition module, for according to each described control signal, controls each submodule in every phase brachium pontis respectively and drops into or cut off, obtain the output voltage waveforms of each submodule described in every phase brachium pontis;
Processing module, the output voltage waveforms for the submodule will dropped in every phase brachium pontis superposes, and obtains every phase brachium pontis output voltage waveforms of described submodule mixed type module Multilevel Inverters.
7. the modulating system of submodule mixed type module Multilevel Inverters according to claim 6, is characterized in that,
Described first determination module, specifically for the described at least one process of often treating each other output order voltage waveform and carrying out in translation, upset and stretching conversion, or often treat each other described the modulating wave that output order voltage waveform is defined as described every phase brachium pontis Neutron module, obtain the modulating wave of each submodule in described every phase brachium pontis.
8. the modulating system of submodule mixed type module Multilevel Inverters according to claim 7, is characterized in that, described first determination module comprises:
First determining unit, for often treating each other output order voltage waveform overturn described, obtains the modulating wave of each half-bridge submodule of the upper brachium pontis of every phase brachium pontis;
Second determining unit, for often treating each other described the modulating wave that output order voltage waveform is defined as each half-bridge submodule of the lower brachium pontis of every phase brachium pontis;
3rd determining unit, for often treating each other output order voltage waveform overturn and translation described, obtains the first modulating wave of each full-bridge submodule of the upper brachium pontis of every phase brachium pontis;
4th determining unit, for often treating each other output order voltage waveform carry out translation to described, obtains the second modulating wave of each full-bridge submodule of the upper brachium pontis of every phase brachium pontis;
5th determining unit, for often treating each other output order voltage waveform carry out translation to described, obtains the 3rd modulating wave of each full-bridge submodule of the lower brachium pontis of every phase brachium pontis;
6th determining unit, for often treating each other output order voltage waveform overturn and translation described, obtains the 4th modulating wave of each full-bridge submodule of the lower brachium pontis of every phase brachium pontis;
Wherein, the concrete formula obtaining the modulating wave of each half-bridge submodule of the upper brachium pontis of described every phase brachium pontis is:
The concrete formula obtaining the modulating wave of each half-bridge submodule of the lower brachium pontis of described every phase brachium pontis is:
The concrete formula obtaining the first modulating wave of each full-bridge submodule of the upper brachium pontis of described every phase brachium pontis is:
The concrete formula obtaining the second modulating wave of each full-bridge submodule of the upper brachium pontis of described every phase brachium pontis is:
The concrete formula of the 3rd modulating wave obtaining each full-bridge submodule of the lower brachium pontis of described every phase brachium pontis is:
The concrete formula of the 4th modulating wave obtaining each full-bridge submodule of the lower brachium pontis of described every phase brachium pontis is;
In formula, described u ref_jfor jth treats each other output order voltage waveform, described j gets A, B or C, represents A phase, B phase or C phase respectively, described u half_j-for the modulating wave of the half-bridge submodule of the upper brachium pontis of jth phase, described u half_j+for the modulating wave of the half-bridge submodule of the lower brachium pontis of jth phase, described u full1_j-the first modulating wave of the full-bridge submodule of brachium pontis is gone up mutually, described u for jth full2_j-the second modulating wave of the full-bridge submodule of brachium pontis is gone up mutually, described u for jth full3_j+for jth descends the 3rd modulating wave of the full-bridge submodule of brachium pontis mutually, described u full4_j+for jth descends the 4th modulating wave of the full-bridge submodule of brachium pontis mutually, described M represents modulation depth, described in for phase voltage effective value, described ω is command voltage waveform frequency to be output, described in for command voltage waveform first phase to be output.
9. the modulating system of submodule mixed type module Multilevel Inverters according to claim 8, it is characterized in that, described comparison module comprises:
First comparing unit, compare for the modulating wave of the carrier wave of each half-bridge submodule of the upper brachium pontis by every phase brachium pontis with described each half-bridge submodule of the upper brachium pontis of every phase brachium pontis, generate the control signal inputing to described each half-bridge submodule of the upper brachium pontis of every phase brachium pontis;
Second comparing unit, compare for the modulating wave of the carrier wave of each half-bridge submodule of the lower brachium pontis by every phase brachium pontis with described each half-bridge submodule of the lower brachium pontis of every phase brachium pontis, generate the control signal inputing to described each half-bridge submodule of the lower brachium pontis of every phase brachium pontis;
3rd comparing unit, compare respectively for described first modulating wave of the carrier wave of each full-bridge submodule of the upper brachium pontis by every phase brachium pontis and described each full-bridge submodule of the upper brachium pontis of every phase brachium pontis and described second modulating wave, generate the first control signal and the second control signal that input to described each full-bridge submodule of the upper brachium pontis of every phase brachium pontis;
4th comparing unit, compare respectively for described 3rd modulating wave of the carrier wave of each full-bridge submodule of the lower brachium pontis by every phase brachium pontis and described each full-bridge submodule of the lower brachium pontis of every phase brachium pontis and described 4th modulating wave, generate the 3rd control signal and the 4th control signal that input to described each full-bridge submodule of the lower brachium pontis of every phase brachium pontis.
10. the modulating system of submodule mixed type module Multilevel Inverters according to claim 6, it is characterized in that, the carrier frequency of half-bridge submodule described in every phase brachium pontis is the twice of the carrier frequency of described full-bridge submodule, the reference phase of the submodule of the upper brachium pontis of every phase brachium pontis is all 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 brachium pontis of every phase brachium pontis is all followed successively by 0, 2 π/N, 2 × 2 π/N, (N-1) × 2 π/N, the reference phase that the carrier phase of full-bridge submodule described in every phase brachium pontis is followed successively by described submodule adds π/4 divided by 2, described in every phase brachium pontis, the carrier phase of half-bridge submodule is maintained described reference phase.
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