CN113809947A - Optimized carrier NSPWM (non-synchronous pulse width modulation) method and device for two-level converter - Google Patents

Optimized carrier NSPWM (non-synchronous pulse width modulation) method and device for two-level converter Download PDF

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CN113809947A
CN113809947A CN202111161249.7A CN202111161249A CN113809947A CN 113809947 A CN113809947 A CN 113809947A CN 202111161249 A CN202111161249 A CN 202111161249A CN 113809947 A CN113809947 A CN 113809947A
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carrier
phase
preset
nspwm
space angle
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CN113809947B (en
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高瞻
周志达
耿程飞
沈文
王二峰
吴轩钦
董瑞勇
潘胜和
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Shenzhen Invt Electric Co Ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483—Converters with outputs that each can have more than two voltages levels
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/12—Arrangements for reducing harmonics from ac input or output
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/501—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode sinusoidal output voltages being obtained by the combination of several pulse-voltages having different amplitude and width
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/5387—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
    • H02M7/53871—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current
    • H02M7/53875—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current with analogue control of three-phase output
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/539—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters with automatic control of output wave form or frequency
    • H02M7/5395—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters with automatic control of output wave form or frequency by pulse-width modulation

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  • Power Engineering (AREA)
  • Inverter Devices (AREA)

Abstract

The application discloses a carrier NSPWM (non-synchronous pulse width modulation) optimization method for a two-level converter. Aiming at the two-level current transformer, the three-phase sine wave power converter superposes the specific voltage U in the space angle region of 330-30 degrees, 90-150 degrees and 210-270 degrees1Superposing a specific voltage U on the three-phase sine wave in the rest area2Obtaining a three-phase modulation wave of the optimized carrier NSPWM; by using an initial value K in the space angle region of 330 DEG to 30 DEG, 90 DEG to 150 DEG, 210 DEG to 270 DEG1Using the initial value of K in the rest area2Obtaining a modulation carrier of the optimized carrier NSPWM;and obtaining a switching signal of the optimized carrier NSPWM based on the comparison between the three-phase modulation wave and the modulation carrier, thereby realizing the optimized carrier NSPWM. Compared with the traditional NSPWM, the method provided by the invention can inhibit common-mode voltage, reduce switching frequency, prevent overvoltage and eliminate even harmonic, and has the advantages of simple calculation and convenience in implementation.

Description

Optimized carrier NSPWM (non-synchronous pulse width modulation) method and device for two-level converter
Technical Field
The invention relates to the technical field of PWM control, in particular to a method and a device for optimizing carrier NSPWM of a two-level converter.
Background
Fig. 1 shows a main circuit topology of a two-level converter. As a key device for electric energy conversion, the two-level converter is widely applied to the fields of new energy power generation, motor driving, electric power reactive compensation and the like.
Defining two level states of the two-level converter from high to low output as 1 and 0, and the dc side voltage as 2E, the space vector of the two-level converter can be summarized in fig. 2. The three-phase switch states, vector types and amplitudes corresponding to the space vectors are listed in table 1.
TABLE 1 switching states and amplitudes corresponding to space vectors of a two-level inverter
Figure BDA0003290005800000011
The common-mode voltage is a reference voltage of the output neutral point of the converter to the ground. The document "diode-clamped three-level inverter common-mode voltage suppression" (wu kory [ J ] report of electrotechnical science, 2015,30(24): 110-. In addition, the common mode voltage can generate high frequency leakage current, generate electromagnetic interference and influence the normal operation of surrounding electrical equipment. In order to reduce the adverse effect of the common-mode voltage under the condition of not adding additional hardware equipment, the research on the pulse width modulation method for inhibiting the common-mode voltage has important practical significance.
Table 2 lists the common mode voltage amplitude corresponding to each space vector of the two-level converter. As can be seen from table 2, non-zero vectors 100, 110, 010, 011, 001, 101 have lower common-mode voltage amplitudes than zero vectors 111 and 000. Therefore, the common mode voltage can be reduced by the pulse width modulation method using only the non-zero vector composite reference voltage.
TABLE 2 common mode voltage amplitude values corresponding to each space vector
Figure BDA0003290005800000021
Document a Near state PWM method with reduced switching frequency and reduced common mode voltage for the same-phase voltage sources inverters (e.un. [ C ]. IEEE International Electric Machines & Drives Conference,2007: 235-. The documents "Performance analysis of reduced common-mode voltage PWM methods and compliance with standard PWM methods for three-phase voltage-source inverters" (Ahmet M. Hava. [ J ]. IEEE Transactions on Energy Conversion,2009,24(1): 241:. su-b.252.) compare the Performance of NSPWM, space vector PWM, effective zero vector PWM, and farthest vector PWM, and indicate that NSPWM can reduce the three-phase switching frequency while suppressing the common-mode voltage, and can achieve better harmonic control effect in the region where the modulation ratio is greater than 0.61. On the basis, the document "an improved modulation strategy with common-mode voltage suppression capability" (zhanxing [ J ]. power electronic technology, 2015,49(8): 89-92.) proposes an improved NSPWM method capable of reducing the switching loss of a device under the condition of non-unit power factor at the converter side, so that the performance of the NSPWM is further improved.
While having the advantages of suppressing common mode voltage and reducing switching frequency, NSPWM also has the following drawbacks:
1) under the action of NSPWM, even harmonics with higher amplitude exist in the output phase voltage of the two-level converter. When the two-level converter is connected with a power grid, the content of each harmonic current on the grid side must be strictly limited in the power grid standard, and the limitation of the harmonic indexes of the public power grid to even harmonics is more strict. Therefore, in order to improve the harmonic performance of NSPWM, even harmonics under the action of NSPWM need to be eliminated;
2) under the action of NSPWM, the output line voltage of the two-level converter has two-level jump, namely, the problem that the line voltage jumps directly between 2E and-2E exists. When the two-level converter is connected with the motor, the voltage jump of the two levels of the line can cause overvoltage at the end of the motor, which is not beneficial to the safe operation of the motor. Therefore, to improve the reliability of NSPWM, it is necessary to prevent overvoltage.
Disclosure of Invention
In order to solve the problems of overvoltage and even harmonic wave existing in the traditional NSPWM, the invention provides a method for optimizing carrier NSPWM by a two-level converter. Compared with the traditional NSPWM, the method can inhibit the amplitude and the change frequency of the common-mode voltage, reduce the switching loss, prevent overvoltage and eliminate even harmonics, so that the method has better harmonic performance and higher reliability. In addition, the method of the invention directly obtains the switching signals of each switching device according to the comparison result of the modulation wave and the modulation carrier wave, and the calculation of the space vector action time is not needed, so the method also has the advantages of simple calculation and convenient realization.
According to the method for optimizing the carrier NSPWM by the two-level converter, a first specific voltage is superposed on a three-phase sine wave in a first preset space angle area, a second preset space angle area and a third preset space angle area, and a second specific voltage is superposed on the three-phase sine wave in a fourth preset space angle area, a fifth preset space angle area and a sixth preset space angle area, so that a three-phase modulation wave of the optimized carrier NSPWM is obtained; obtaining a modulation carrier of an optimized carrier NSPWM by using a rising carrier with an initial value of a first preset value in the first preset space angle region, the second preset space angle region and the third preset space angle region and using a falling carrier with an initial value of a second preset value in the fourth preset space angle region, the fifth preset space angle region and the sixth preset space angle region; based on the comparison between the three-phase modulation wave and the modulation carrier, obtaining the three-phase modulation wave of the optimized carrier NSPWM by superimposing a first specific voltage on the three-phase sine wave in a first preset spatial angle region, a second preset angular region and a third preset spatial angle region, and superimposing a second specific voltage on the three-phase sine wave in a fourth preset spatial angle region, a fifth preset spatial angle region and a sixth preset spatial angle region, specifically including:
in the first preset space angle area, making Uam＝Uas+U1，Ubm＝-Ubs-U1，Ucm＝Ucs+U1；
In the fourth preset space angle area, making Uam＝-Uas-U2，Ubm＝Ubs+U2，Ucm＝Ucs+U2；
In the second preset space angle area, making Uam＝Uas+U1，Ubm＝Ubs+U1，Ucm＝-Ucs-U1；
In the fifth preset space angle area, making Uam＝Uas+U2，Ubm＝-Ubs-U2，Ucm＝Ucs+U2；
In the third preset space angle area, making Uam＝-Uas-U1，Ubm＝Ubs+U1，Ucm＝Ucs+U1；
In the sixth preset space angle area, making Uam＝Uas+U2，Ubm＝Ubs+U2，Ucm＝-Ucs-U2；
Wherein the three-phase sine wave is a three-phase sine wave with the maximum peak value in the linear modulation ratio region being the difference between a second preset value and a first preset value, and U1Represents said first specific voltage, U2Represents said second specific voltage, Uas、Ubs、UcsAn A-phase sine wave, a B-phase sine wave and a C-phase sine wave, U, respectively representing the three-phase sine wavesam、Ubm、UcmAnd the A-phase modulation wave, the B-phase modulation wave and the C-phase modulation wave respectively represent the three-phase modulation wave.
Preferably, the first specific voltage is defined as follows:
U1＝K2-max(Uas,Ubs,Ucs)
in the above formula, K2Represents said second preset value, max (U)as,Ubs,Ucs) Represents Uas、Ubs、UcsMaximum value of (1);
the second specific voltage is defined as follows:
U2＝K1-min(Uas,Ubs,Ucs)
in the above formula, K1Represents said first preset value, min (U)as，Ubs，Ucs) Represents Uas、Ubs、UcsMinimum value of (1).
Preferably, the obtaining of the modulated carrier of the optimized carrier NSPWM by using the rising carrier with the initial value being the first preset value in the first preset spatial angle region, the second preset angular region, and the third preset spatial angle region and using the falling carrier with the initial value being the second preset value in the fourth preset spatial angle region, the fifth preset spatial angle region, and the sixth preset spatial angle region specifically includes:
setting U in the first preset space angle region, the second preset space angle region and the third preset space angle regioncarrier＝UPcarrier；
Setting U in the fourth preset space angle area, the fifth preset space angle area and the sixth preset space angle areacarrier＝DNcarrier；
Wherein, UcarrierModulation representing optimized carrier NSPWMSystem of carrier waves, UPcarrierRepresenting rising carriers, DN, with an initial value of a first predetermined valuecarrierRepresenting the descending carrier with the initial value of the second preset value.
Preferably, when 0. ltoreq. trun＜tsampleWhen the temperature of the water is higher than the set temperature,
the definition of the rising carrier with the initial value as the first preset value is as follows:
Figure BDA0003290005800000041
the definition of the descending carrier with the initial value as the second preset value is as follows:
Figure BDA0003290005800000042
when t issample≤trun＜2tsampleWhen the temperature of the water is higher than the set temperature,
the definition of the rising carrier with the initial value as the first preset value is as follows:
Figure BDA0003290005800000043
the definition of the descending carrier with the initial value as the second preset value is as follows:
Figure BDA0003290005800000044
wherein, K1Represents said first preset value, K2Represents said second preset value, tsampleRepresenting the sampling period, trunIs of value 0 to 2tsampleTime running variables that vary cyclically between.
Preferably, the switching signal of the optimized carrier NSPWM is obtained by comparing the three-phase modulation wave with the modulation carrier, so that the method for implementing the optimized carrier NSPWM includes:
in the first preset spatial angle region and the fifth preset spatial angle regionPresetting a spatial angle region as Uam≥UcarrierWhen the phase A switching signal is OX, and when U isam＜UcarrierWhen the phase A switching signal is XO; when U is turnedbm≥UcarrierWhen the phase B switching signal is XO, the phase B switching signal is Ubm＜UcarrierWhen the phase B switching signal is OX; when U is turnedcm≥UcarrierWhen the phase C switching signal is OX, and when U iscm＜UcarrierWhen the phase C switching signal is XO;
in the fourth preset space angle region and the third preset space angle region, when U is in the stateam≥UcarrierWhen the phase A switching signal is XO, the phase A switching signal is Uam＜UcarrierWhen the phase A switching signal is OX; when U is turnedbm≥UcarrierWhen it is, the B-phase switch signal is OX, and when it is Ubm＜UcarrierWhen the phase B switching signal is XO; when U is turnedcm≥UcarrierWhen the phase C switching signal is OX, and when U iscm＜UcarrierWhen the phase C switching signal is XO;
in the second preset space angle region and the sixth preset space angle region, when U is in the stateam≥UcarrierWhen the phase A switching signal is OX, and when U isam＜UcarrierWhen the phase A switching signal is XO; when U is turnedbm≥UcarrierWhen it is, the B-phase switch signal is OX, and when it is Ubm＜UcarrierWhen the phase B switching signal is XO; when U is turnedcm≥UcarrierWhen the phase C switching signal is XO, the phase U switching signal is set to XOcm＜UcarrierWhen the phase C switching signal is OX;
wherein, Uam、Ubm、UcmA-phase modulated wave, B-phase modulated wave and C-phase modulated wave, U, representing the three-phase modulated wavecarrierThe modulator represents a modulated carrier of an optimized carrier NSPWM, XO represents that an upper bridge arm switching device of a corresponding phase is turned off and a lower bridge arm switching device of the corresponding phase is turned on, and OX represents that the upper bridge arm switching device of the corresponding phase is turned on and the lower bridge arm switching device of the corresponding phase is turned off.
Preferably, the first preset value is-1, and the second preset value is 1.
The invention also provides a device for optimizing carrier NSPWM by using the two-level converter, which comprises the following components:
a three-phase modulation wave acquisition module for superposing a first specific voltage U on the three-phase sine wave in a first preset spatial angle region, a second preset angular region and a third preset spatial angle region1Superposing second specific voltage on the three-phase sine wave in a fourth preset space angle area, a fifth preset space angle area and a sixth preset space angle area to obtain a three-phase modulation wave of the optimized carrier NSPWM;
a modulated carrier obtaining module, configured to use a rising carrier with an initial value being a first preset value in the first preset spatial angle region, the second preset spatial angle region, and the third preset spatial angle region, and use a falling carrier with an initial value being a second preset value in the fourth preset spatial angle region, the fifth preset spatial angle region, and the sixth preset spatial angle region, so as to obtain a modulated carrier of an optimized carrier NSPWM;
and the switching signal acquisition module is used for comparing the three-phase modulation wave with the modulation carrier to obtain a switching signal of the optimized carrier NSPWM, so that the optimized carrier NSPWM is realized.
The device for optimizing the carrier NSPWM by the two-level converter has the same beneficial effects as the method for optimizing the carrier NSPWM by the two-level converter.
Drawings
Fig. 1 is a main circuit topology of a two-level converter related to the background art;
fig. 2 is a space vector diagram of a two-level current transformer related to the background art;
fig. 3 is a flowchart of a method for optimizing carrier NSPWM of a two-level converter according to an embodiment of the present invention;
FIG. 4 shows phase voltages, line voltages and common mode voltages of a two-level converter under SVPWM;
fig. 5a, 5b, and 5c are simulation results of conventional NSPWM, wherein: fig. 5a is a phase voltage, a line voltage and a common mode voltage of a two-level converter under the action of the traditional NSPWM, fig. 5b is an amplitude analysis result of each harmonic of the phase voltage of the traditional NSPWM, and fig. 5c is an output line voltage of the two-level converter under the action of the traditional NSPWM;
fig. 6a, 6b, 6c, and 6d are simulation results of carrier NSPWM optimized by the method of the present invention, wherein: fig. 6a shows phase voltage, line voltage and common mode voltage of a two-level converter under the action of an optimized carrier NSPWM, fig. 6b shows the amplitude analysis result of each subharmonic of the phase voltage of the optimized carrier NSPWM, fig. 6c shows output line voltage of the two-level converter under the action of the optimized carrier NSPWM, and fig. 6d shows the simulation result of the optimized carrier NSPWM comparing a three-phase modulation wave with a modulation carrier to obtain a switching signal of a three-phase device;
fig. 7a and 7b are simulation results of carrier NSPWM optimized by the method of the present invention under different fundamental frequencies, different carrier frequencies, and different modulation ratios in the embodiment, where: fig. 7a shows phase voltages, line voltages, common mode voltages and modulation waves of the optimized carrier NSPWM at different fundamental frequencies, different carrier frequencies and different modulation ratios, and fig. 7b shows amplitude analysis results of harmonics of phase voltages of the optimized carrier NSPWM at different fundamental frequencies, different carrier frequencies and different modulation ratios.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In order to solve the problems of overvoltage and even harmonic wave existing in the traditional NSPWM, the invention provides a method for optimizing carrier NSPWM by a two-level converter, which superposes a specific voltage U on a three-phase sine wave in a space angle region of 330-30 degrees, 90-150 degrees and 210-270 degrees1Superposing a specific voltage U on the three-phase sine wave in the rest area2Obtaining a three-phase modulation wave of the optimized carrier NSPWM; by using initial values in the spatial angle region of 330 DEG to 30 DEG, 90 DEG to 150 DEG, 210 DEG to 270 DEGIs K1Using the initial value of K in the rest area2The invention obtains the modulation carrier of the optimized carrier NSPWM; based on the comparison between the three-phase modulation wave and the modulation carrier, the invention obtains the switching signal of the optimized carrier NSPWM, thereby realizing the optimized carrier NSPWM. Compared with the traditional NSPWM, the method can inhibit the amplitude and the change frequency of the common-mode voltage, reduce the switching loss, prevent overvoltage and eliminate even harmonics, so that the method has better harmonic performance and higher reliability. In addition, the method of the invention directly obtains the switching signals of each switching device according to the comparison result of the modulation wave and the modulation carrier wave, and the calculation of the space vector action time is not needed, so the method also has the advantages of simple calculation and convenient realization. A carrier NSPWM (non-synchronous pulse width modulation) optimization method of a two-level converter comprises the following specific implementation processes:
step 1, obtaining a three-phase modulation wave of an optimized carrier NSPWM:
in this embodiment, the first preset spatial angle region is set to be a 330 ° to 30 ° spatial angle region, the second preset spatial angle region is set to be a 90 ° to 150 ° spatial angle region, the third preset spatial angle region is set to be a 210 ° to 270 ° spatial angle region, the fourth preset spatial angle region is set to be a 30 ° to 90 ° spatial angle region, the fifth preset spatial angle region is set to be a 150 ° to 210 ° spatial angle region, and the sixth preset spatial angle region is set to be a 270 ° to 330 ° spatial angle region.
Further, in the step, a specific voltage U is superimposed on the three-phase sine wave in a space angle region of 330 ° to 30 °, 90 ° to 150 °, 210 ° to 270 °1Superposing a specific voltage U on the three-phase sine wave in the rest area2The method for obtaining the three-phase modulation wave of the optimized carrier NSPWM comprises the following steps:
1) when in the space angle region of 330 degrees to 30 degrees, let Uam＝Uas+U1，Ubm＝-Ubs-U1，Ucm＝Ucs+U1；
2) When in the space angle region of 30 degrees to 90 degrees, let Uam＝-Uas-U2，Ubm＝Ubs+U2，Ucm＝Ucs+U2；
3) When in the space angle region of 90-150 degrees, let Uam＝Uas+U1，Ubm＝Ubs+U1，Ucm＝-Ucs-U1；
4) When in the space angle region of 150 degrees to 210 degrees, let Uam＝Uas+U2，Ubm＝-Ubs-U2，Ucm＝Ucs+U2；
5) When in the space angle region of 210 degrees to 270 degrees, let Uam＝-Uas-U1，Ubm＝Ubs+U1，Ucm＝Ucs+U1；
6) When in the space angle region of 270 degrees to 330 degrees, let Uam＝Uas+U2，Ubm＝Ubs+U2，Ucm＝-Ucs-U2。
In the above three-phase modulation wave method for obtaining optimized carrier NSPWM, Uas、Ubs、UcsRepresents the maximum peak-to-peak value (K) in the linear modulation ratio region2-K1) Three-phase sine wave of (U)am、Ubm、UcmThree-phase modulated wave representing an optimized carrier NSPWM, in which a specific voltage U is applied1The calculation method of (2) is as follows:
U1＝K2-max(Uas,Ubs,Ucs) (1)
in formula (1), max (U)as,Ubs,Ucs) Represents the maximum of a three-phase sine wave;
specific voltage U2The calculation method of (2):
U2＝K1-min(Uas,Ubs,Ucs) (2)
in formula (2), min (U)as,Ubs,Ucs) Representing the minimum of a three-phase sine wave.
Step 2, obtaining a modulation carrier of the optimized carrier NSPWM:
the invention uses the initial value K in the space angle region of 330 degrees to 30 degrees, 90 degrees to 150 degrees, 210 degrees to 270 degrees1Using the initial value of K in the rest area2The method for obtaining the modulation carrier of the optimized carrier NSPWM is as follows:
1) in the space angle region of 330 degrees to 30 degrees, 90 degrees to 150 degrees and 210 degrees to 270 degrees, U is arrangedcarrier＝UPcarrier；
2) In the space angle region of 30-90 degrees, 150-210 degrees and 270-330 degrees, U is arrangedcarrier＝DNcarrier。
In the carrier modulation method for obtaining the optimized carrier NSPWM, UcarrierModulated carrier, UP, representing optimized carrier NSPWMcarrierRepresenting an initial value of K1Up carrier of (DN)carrierRepresenting an initial value of K2Is detected. Wherein the initial value is K1The setting method of the rising carrier wave of (3) is as follows:
Figure BDA0003290005800000071
in the formula (3), tsampleRepresenting the sampling period, trunIs of value 0 to 2tsampleTime running variables that vary cyclically between;
initial value is K2The setting method of the reduced carrier is as follows (4):
Figure BDA0003290005800000081
in the formula (4), tsampleRepresenting the sampling period, trunIs of value 0 to 2tsampleTime running variables that vary cyclically between.
Step 3, obtaining a switching signal of the optimized carrier NSPWM:
based on the comparison between the three-phase modulation wave and the modulation carrier, the invention obtains the switching signal of the optimized carrier NSPWM, thereby realizing the method for optimizing the carrier NSPWM as follows:
1) in the space angle region of 330 deg. to 30 deg. and 150 deg. to 210 deg., when U isam≥UcarrierWhen the phase A switching signal is OX, and when U isam＜UcarrierWhen the phase A switching signal is XO; when U is turnedbm≥UcarrierWhen the phase B switching signal is XO, the phase B switching signal is Ubm＜UcarrierWhen the phase B switching signal is OX; when U is turnedcm≥UcarrierWhen the phase C switching signal is OX, and when U iscm＜UcarrierWhen the phase C switching signal is XO;
2) in the spatial angle regions of 30 DEG to 90 DEG and 210 DEG to 270 DEG when U is turnedam≥UcarrierWhen the phase A switching signal is XO, the phase A switching signal is Uam＜UcarrierWhen the phase A switching signal is OX; when U is turnedbm≥UcarrierWhen it is, the B-phase switch signal is OX, and when it is Ubm＜UcarrierWhen the phase B switching signal is XO; when U is turnedcm≥UcarrierWhen the phase C switching signal is OX, and when U iscm＜UcarrierWhen the phase C switching signal is XO;
3) in the spatial angle regions of 90 DEG to 150 DEG and 270 DEG to 330 DEG when U is turnedam≥UcarrierWhen the phase A switching signal is OX, and when U isam＜UcarrierWhen the phase A switching signal is XO; when U is turnedbm≥UcarrierWhen it is, the B-phase switch signal is OX, and when it is Ubm＜UcarrierWhen the phase B switching signal is XO; when U is turnedcm≥UcarrierWhen the phase C switching signal is XO, the phase U switching signal is set to XOcm＜UcarrierAt this time, the C-phase switching signal is set to OX.
In the switching signal method for obtaining the optimized carrier NSPWM, XO represents that the corresponding phase upper bridge arm switching device is turned off and the corresponding phase lower bridge arm switching device is turned on, and OX represents that the corresponding phase upper bridge arm switching device is turned on and the corresponding phase lower bridge arm switching device is turned off.
In the above process, K1And K2Can take any value as long as K is satisfied1Less than K2That is, for example K1A value of 0, K2A value of 2, or K1The value is-1, K2Value 1, etc., hereinafter denoted by K1The value is-1, K2The case where the value is 1 is one embodiment of the invention, and the effect of the invention will be described.
A method for optimizing carrier NSPWM for a two-level converter is shown in fig. 3, and the specific implementation flow is as follows:
by superimposing a specific voltage U on a three-phase sine wave in a spatial angular region of 330 DEG to 30 DEG, 90 DEG to 150 DEG, 210 DEG to 270 DEG1Superposing a specific voltage U on the three-phase sine wave in the rest area2Obtaining a three-phase modulation wave of the optimized carrier NSPWM; the method comprises the steps that a rising carrier with an initial value of-1 is used in a space angle region of 330 degrees to 30 degrees, 90 degrees to 150 degrees and 210 degrees to 270 degrees, and a falling carrier with an initial value of 1 is used in the rest regions, so that a modulation carrier of an optimized carrier NSPWM is obtained; based on the comparison between the three-phase modulation wave and the modulation carrier, the invention obtains the switching signal of the optimized carrier NSPWM, thereby realizing the optimized carrier NSPWM.
1. Obtaining three-phase modulation wave of optimized carrier NSPWM
Superimposing a specific voltage U on the three-phase sine wave in a spatial angle region of 330 DEG to 30 DEG, 90 DEG to 150 DEG, and 210 DEG to 270 DEG1Superposing a specific voltage U on the three-phase sine wave in the rest area2The method for obtaining the three-phase modulation wave of the optimized carrier NSPWM comprises the following steps:
1) when in the space angle region of 330 degrees to 30 degrees, let Uam＝Uas+U1，Ubm＝-Ubs-U1，Ucm＝Ucs+U1；
2) When in the space angle region of 30 degrees to 90 degrees, let Uam＝-Uas-U2，Ubm＝Ubs+U2，Ucm＝Ucs+U2；
3) When in the space angle region of 90-150 degrees, let Uam＝Uas+U1，Ubm＝Ubs+U1，Ucm＝-Ucs-U1；
4) When in the space angle region of 150 degrees to 210 degrees, let Uam＝Uas+U2，Ubm＝-Ubs-U2，Ucm＝Ucs+U2；
5) When in the space angle region of 210 degrees to 270 degrees, let Uam＝-Uas-U1，Ubm＝Ubs+U1，Ucm＝Ucs+U1；
6) When in the space angle region of 270 degrees to 330 degrees, let Uam＝Uas+U2，Ubm＝Ubs+U2，Ucm＝-Ucs-U2。
In the above three-phase modulation wave method for obtaining optimized carrier NSPWM, Uam、Ubm、UcmThree-phase modulated wave, U, representing an optimized carrier NSPWMas、Ubs、UcsRepresenting a three-phase sine wave, in which a specific voltage U1The calculation method of (3) is as follows:
U1＝1-max(Uas,Ubs,Ucs) (5)
in formula (5), max (U)as,Ubs,Ucs) Represents the maximum of a three-phase sine wave;
specific voltage U2The calculation method of (2) is as follows:
U2＝-1-min(Uas,Ubs,Ucs) (6)
in formula (6), min (U)as,Ubs,Ucs) Representing the minimum of a three-phase sine wave.
2. Obtaining modulated carrier of optimized carrier NSPWM
The method for obtaining the modulation carrier of the optimized carrier NSPWM by using the rising carrier with the initial value of-1 in the space angle regions of 330 degrees to 30 degrees, 90 degrees to 150 degrees and 210 degrees to 270 degrees and using the falling carrier with the initial value of 1 in the other regions comprises the following steps:
1) in the space angle region of 330 degrees to 30 degrees, 90 degrees to 150 degrees and 210 degrees to 270 degrees, U is arrangedcarrier＝UPcarrier；
2) At 30 deg. to 90 deg., 150 deg. to 210 deg., 270 deg. °To a space angle region of 330 degrees, set Ucarrier＝DNcarrier。
In the carrier modulation method for obtaining the optimized carrier NSPWM, UcarrierModulated carrier, UP, representing optimized carrier NSPWMcarrierRepresenting a rising carrier with an initial value of-1, DNcarrierRepresenting a falling carrier with an initial value of 1. Wherein, the setting method of the rising carrier with the initial value of-1 is as the formula (7):
Figure BDA0003290005800000091
in the formula (7), tsampleRepresenting the sampling period, trunIs of value 0 to 2tsampleTime running variables that vary cyclically between; the setting method of the descending carrier with the initial value of 1 is as the following formula (8):
Figure BDA0003290005800000101
3. obtaining switching signals of optimized carrier NSPWM
Based on the comparison between the three-phase modulation wave and the modulation carrier, the invention obtains the switching signal of the optimized carrier NSPWM, thereby realizing the method for optimizing the carrier NSPWM as follows:
1) in the space angle region of 330 deg. to 30 deg. and 150 deg. to 210 deg., when U isam≥UcarrierWhen the phase A switching signal is OX, and when U isam＜UcarrierWhen the phase A switching signal is XO; when U is turnedbm≥UcarrierWhen the phase B switching signal is XO, the phase B switching signal is Ubm＜UcarrierWhen the phase B switching signal is OX; when U is turnedcm≥UcarrierWhen the phase C switching signal is OX, and when U iscm＜UcarrierWhen the phase C switching signal is XO;
2) in the spatial angle regions of 30 DEG to 90 DEG and 210 DEG to 270 DEG when U is turnedam≥UcarrierWhen the phase A switching signal is XO, the phase A switching signal is Uam＜UcarrierWhen the phase A switching signal is OX; when U is turnedbm≥UcarrierWhen it is, the B-phase switch signal is OX, and when it is Ubm＜UcarrierWhen the phase B switching signal is XO; when U is turnedcm≥UcarrierWhen the phase C switching signal is OX, and when U iscm＜UcarrierWhen the phase C switching signal is XO;
3) in the spatial angle regions of 90 DEG to 150 DEG and 270 DEG to 330 DEG when U is turnedam≥UcarrierWhen the phase A switching signal is OX, and when U isam＜UcarrierWhen the phase A switching signal is XO; when U is turnedbm≥UcarrierWhen it is, the B-phase switch signal is OX, and when it is Ubm＜UcarrierWhen the phase B switching signal is XO; when U is turnedcm≥UcarrierWhen the phase C switching signal is XO, the phase U switching signal is set to XOcm＜UcarrierAt this time, the C-phase switching signal is set to OX.
In the switching signal method for obtaining the optimized carrier NSPWM, XO represents that the corresponding phase upper bridge arm switching device is turned off and the corresponding phase lower bridge arm switching device is turned on, and OX represents that the corresponding phase upper bridge arm switching device is turned on and the corresponding phase lower bridge arm switching device is turned off.
The following describes the effects of the present invention with reference to the drawings.
According to the embodiment of the invention, a two-level inverter model is built by means of PSIM software, and the effectiveness of the two-level converter optimized carrier NSPWM method for preventing overvoltage and eliminating even harmonics is verified by utilizing simulation. The simulation conditions of the embodiment are as follows: the voltage on the direct current side is 2000V, the output fundamental frequency is 50Hz, the carrier frequency is 1000Hz, the modulation ratio is 0.8, and the simulation step size is 2 us.
Fig. 4 shows phase voltage, line voltage and common mode voltage of the two-level converter under SVPWM. As can be seen from fig. 4, under the SVPWM, the magnitude of the common mode voltage of the two-level inverter is half of the value of the dc-side voltage, that is, as can be seen from fig. 4, the magnitude of the common mode voltage of the present embodiment is only 1000V, and the variation frequency of the common mode voltage is three times of the sampling frequency. High-amplitude and high-frequency common-mode voltage can affect the service life of a motor and equipment communication, and in order to improve the safety and reliability of a system, the common-mode voltage needs to be inhibited.
Fig. 5a, 5b, and 5c are simulation results of the conventional NSPWM in the embodiment, in which: fig. 5a shows phase voltage, line voltage and common mode voltage of the two-level converter under the action of the conventional NSPWM, fig. 5b shows the amplitude analysis result of each harmonic of the phase voltage of the conventional NSPWM, and fig. 5c shows the output line voltage of the two-level converter under the action of the conventional NSPWM. From this, it can be seen that:
1) comparing fig. 4 and 5a, under the action of the conventional NSPWM, the magnitude of the common mode voltage of the two-level inverter is reduced to one sixth of the value of the dc-side voltage, and the variation frequency of the common mode voltage is reduced to twice the sampling frequency, compared to SVPWM. Therefore, the traditional NSPWM can effectively restrain the amplitude and the change frequency of the common-mode voltage;
2) comparing fig. 4 and 5a, the conventional NSPWM reduces the switching frequency by one third by placing the phase voltage clamp in a certain level state, compared to SVPWM. Therefore, the conventional NSPWM can effectively reduce the switching loss;
3) analyzing fig. 5b, under the action of the conventional NSPWM, the output phase voltages of the two-level converter simultaneously include odd harmonics and even harmonics with higher amplitude. When the two-level converter is connected with a power grid, the content of each harmonic current on the grid side must be strictly limited in the power grid standard, and the limitation of the harmonic indexes of the public power grid to even harmonics is more strict. Therefore, in order to improve the harmonic performance of the traditional NSPWM, even harmonics under the action of the traditional NSPWM need to be eliminated;
4) analyzing fig. 5C, under the effect of the conventional NSPWM, the line voltage between the phases a and B of the two-level converter has two level jumps when entering the spatial angle region of 30 ° to 90 ° or 270 ° to 330 °, the line voltage between the phases B and C has two level jumps when entering the spatial angle region of 30 ° to 90 ° or 330 ° to 30 °, and the line voltage between the phases C and a has two level jumps when entering the spatial angle region of 270 ° to 330 ° or 330 ° to 30 °. When the two-level converter is connected with the motor, the voltage jump of the two levels of the line can cause overvoltage at the end of the motor, which is not beneficial to the safe operation of the motor. Therefore, in order to improve the reliability of the conventional NSPWM, it is necessary to prevent the overvoltage.
Fig. 6a, 6b, 6c, and 6d are simulation results of carrier NSPWM optimized by the method of the present invention in the embodiment, wherein: fig. 6a shows phase voltage, line voltage and common mode voltage of the two-level converter under the action of the optimized carrier NSPWM, fig. 6b shows the amplitude analysis result of each subharmonic of the phase voltage of the optimized carrier NSPWM, fig. 6c shows output line voltage of the two-level converter under the action of the optimized carrier NSPWM, and fig. 6d shows the simulation result of the optimized carrier NSPWM comparing the three-phase modulation wave and the modulation carrier to obtain the switching signal of the three-phase device. The analysis shows that:
1) comparing fig. 4 and fig. 6a, compared with SVPWM, under the action of the optimized carrier NSPWM of the present invention, the magnitude of the common mode voltage of the two-level inverter is reduced to one sixth of the value of the dc-side voltage, and the variation frequency of the common mode voltage is reduced to twice of the sampling frequency. Therefore, the optimized carrier NSPWM can effectively restrain the amplitude and the change frequency of the common-mode voltage;
2) comparing fig. 4 and 6a, compared to SVPWM, the optimized carrier NSPWM of the present invention reduces the switching frequency by one third by placing the phase voltage clamp in a specific level state. Therefore, the optimized carrier NSPWM can effectively reduce the switching loss;
3) comparing fig. 5b and fig. 6b, compared with the conventional NSPWM, under the action of the optimized carrier NSPWM of the present invention, the harmonic component of the output phase voltage of the two-level converter only contains an odd harmonic component. Therefore, even harmonics can be effectively eliminated by optimizing carrier NSPWM, so that the harmonic performance is better;
4) comparing fig. 5c and fig. 6c, compared with the conventional NSPWM, the optimized carrier NSPWM of the present invention can ensure that there is no two-level jump in the output line voltage of the two-level converter by using the rising carrier with the initial value of-1 in the space angle regions of 330 ° to 30 °, 90 ° to 150 °, 210 ° to 270 °, and using the falling carrier with the initial value of 1 in the remaining regions. Therefore, the optimized carrier NSPWM can effectively prevent overvoltage, so that higher reliability is achieved;
5) analyzing fig. 6d, the optimized carrier NSPWM of the present invention obtains the switching signal of the three-phase device based on the comparison between the three-phase modulation wave and the modulated carrier, and the time of the space vector does not need to be calculated, so that the present invention has the advantages of simple operation and easy implementation. (indicating which is the three-phase modulated wave and which is the three-phase carrier wave)
For example in the spatial angle region of 270 DEG to 330 DEGThe comparison method comprises the following steps: when U is turnedam≥UcarrierWhen the phase A switching signal is OX, and when U isam＜UcarrierWhen the phase A switching signal is XO; when U is turnedbm≥UcarrierWhen it is, the B-phase switch signal is OX, and when it is Ubm＜UcarrierWhen the phase B switching signal is XO; when U is turnedcm≥UcarrierWhen the phase C switching signal is XO, the phase U switching signal is set to XOcm＜UcarrierAt this time, the C-phase switching signal is set to OX.
And in fig. 6d, in the region of the space angle of 270 ° to 330 ° (to be specifically illustrated)
Changing the fundamental frequency from 50Hz to 100Hz, the carrier frequency from 1000Hz to 4000Hz, and the modulation ratio from 0.8 to 0.95, fig. 7a and 7b are simulation results of the optimized carrier NSPWM of the method of the present invention in the embodiment under different fundamental frequencies, different carrier frequencies, and different modulation ratios, wherein: fig. 7a shows phase voltages, line voltages, common mode voltages and modulation waves of the optimized carrier NSPWM at different fundamental frequencies, different carrier frequencies and different modulation ratios, and fig. 7b shows amplitude analysis results of harmonics of phase voltages of the optimized carrier NSPWM at different fundamental frequencies, different carrier frequencies and different modulation ratios. As can be seen from fig. 7a and 7b, when the fundamental frequency, the carrier frequency and the modulation ratio are changed, the carrier NSPWM optimized according to the present invention can still effectively suppress the common mode voltage, reduce the switching frequency, prevent the overvoltage, and eliminate the even harmonics.
As shown in fig. 4 to 7b, the results of the embodiment verify the effectiveness of the two-level converter optimized carrier NSPWM method for preventing overvoltage and eliminating even harmonics according to the present invention. Compared with the traditional NSPWM, the method can inhibit the amplitude and the change frequency of the common-mode voltage, reduce the switching loss, prevent overvoltage and eliminate even harmonics, so that the method has better harmonic performance and higher reliability. In addition, the method of the invention directly obtains the switching signals of each switching device according to the comparison result of the modulation wave and the modulation carrier wave, and the calculation of the space vector action time is not needed, so the method also has the advantages of simple calculation and convenient realization.
Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The two-level converter carrier NSPWM optimizing method provided by the present invention is described in detail above, and a specific example is applied in the present disclosure to explain the principle and the implementation of the present invention, and the description of the above embodiment is only used to help understanding the method and the core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.

Claims (8)

1. A method for optimizing carrier NSPWM by a two-level converter is characterized by comprising the following steps:
superposing first specific voltage on the three-phase sine wave in a first preset space angle area, a second preset space angle area and a third preset space angle area, and superposing second specific voltage on the three-phase sine wave in a fourth preset space angle area, a fifth preset space angle area and a sixth preset space angle area to obtain a three-phase modulation wave of the optimized carrier NSPWM;
obtaining a modulation carrier of an optimized carrier NSPWM by using a rising carrier with an initial value of a first preset value in the first preset space angle region, the second preset space angle region and the third preset space angle region and using a falling carrier with an initial value of a second preset value in the fourth preset space angle region, the fifth preset space angle region and the sixth preset space angle region;
and obtaining a switching signal of the optimized carrier NSPWM based on the comparison between the three-phase modulation wave and the modulation carrier, thereby realizing the optimized carrier NSPWM.
2. The method for optimizing a carrier NSPWM by a two-level converter according to claim 1, wherein the obtaining of the three-phase modulation wave of the optimized carrier NSPWM by superimposing a first specific voltage on the three-phase sine wave in a first predetermined spatial angle region, a second predetermined spatial angle region, and a third predetermined spatial angle region, and superimposing a second specific voltage on the three-phase sine wave in a fourth predetermined spatial angle region, a fifth predetermined spatial angle region, and a sixth predetermined spatial angle region specifically comprises:
in the first preset space angle area, making Uam＝Uas+U1，Ubm＝-Ubs-U1，Ucm＝Ucs+U1；
In the fourth preset space angle area, making Uam＝-Uas-U2，Ubm＝Ubs+U2，Ucm＝Ucs+U2；
In the second preset space angle area, making Uam＝Uas+U1，Ubm＝Ubs+U1，Ucm＝-Ucs-U1；
In the fifth preset space angle area, making Uam＝Uas+U2，Ubm＝-Ubs-U2，Ucm＝Ucs+U2；
In the third preset space angle area, making Uam＝-Uas-U1，Ubm＝Ubs+U1，Ucm＝Ucs+U1；
In the sixth preset space angle area, making Uam＝Uas+U2，Ubm＝Ubs+U2，Ucm＝-Ucs-U2；
Wherein the three-phase sine wave is a three-phase sine wave with the maximum peak value in the linear modulation ratio region being the difference between a second preset value and a first preset value, and U1Represents said first specific voltage, U2Represents said second specific voltage, Uas、Ubs、UcsAn A-phase sine wave, a B-phase sine wave and a C-phase sine wave, U, respectively representing the three-phase sine wavesam、Ubm、UcmAnd the A-phase modulation wave, the B-phase modulation wave and the C-phase modulation wave respectively represent the three-phase modulation wave.
3. The two-level converter optimized-carrier NSPWM method of claim 2,
the first specific voltage is defined as follows:
U1＝K2-max(Uas,Ubs,Ucs)
in the above formula, K2Represents said second preset value, max (U)as,Ubs,Ucs) Represents Uas、Ubs、UcsMaximum value of (1);
the second specific voltage is defined as follows:
U2＝K1-min(Uas,Ubs,Ucs)
in the above formula, K1Represents said first preset value, min (U)as，Ubs，Ucs) Represents Uas、Ubs、UcsMinimum value of (1).
4. The method according to claim 1, wherein the obtaining of the modulation carrier of the optimized carrier NSPWM by using a rising carrier with a first preset value in the first preset space angle region, the second preset space angle region, and the third preset space angle region and using a falling carrier with a second preset value in the fourth preset space angle region, the fifth preset space angle region, and the sixth preset space angle region specifically comprises:
setting U in the first preset space angle region, the second preset space angle region and the third preset space angle regioncarrier＝UPcarrier；
Setting U in the fourth preset space angle area, the fifth preset space angle area and the sixth preset space angle areacarrier＝DNcarrier；
Wherein, UcarrierModulated carrier, UP, representing optimized carrier NSPWMcarrierRepresenting rising carriers, DN, with an initial value of a first predetermined valuecarrierRepresenting the descending carrier with the initial value of the second preset value.
5. The two-level converter optimized-carrier NSPWM method of claim 4,
when t is more than or equal to 0run＜tsampleWhen the temperature of the water is higher than the set temperature,
the definition of the rising carrier with the initial value as the first preset value is as follows:
Figure FDA0003290005790000021
the definition of the descending carrier with the initial value as the second preset value is as follows:
Figure FDA0003290005790000022
when t issample≤trun＜2tsampleWhen the temperature of the water is higher than the set temperature,
the definition of the rising carrier with the initial value as the first preset value is as follows:
Figure FDA0003290005790000023
the definition of the descending carrier with the initial value as the second preset value is as follows:
Figure FDA0003290005790000024
wherein, K1Represents said first preset value, K2Represents said second preset value, tsampleRepresenting the sampling period, trunIs of value 0 to 2tsampleTime running variables that vary cyclically between.
6. The NSPWM method of the two-level converter optimizing carrier according to claim 1, wherein the switching signal of the optimized carrier NSPWM is obtained based on the comparison between the three-phase modulation wave and the modulation carrier, so as to realize the optimized carrier NSPWM method as follows:
in the first preset space angle region and the fifth preset space angle region, when U is in the stateam≥UcarrierWhen the phase A switching signal is OX, and when U isam＜UcarrierWhen the phase A switching signal is XO; when U is turnedbm≥UcarrierWhen the phase B switching signal is XO, the phase B switching signal is Ubm＜UcarrierWhen the phase B switching signal is OX; when U is turnedcm≥UcarrierWhen the phase C switching signal is OX, and when U iscm＜UcarrierWhen the phase C switching signal is XO;
in the fourth preset space angle region and the third preset space angle region, when U is in the stateam≥UcarrierWhen the phase A switching signal is XO, the phase A switching signal is Uam＜UcarrierWhen the phase A switching signal is OX; when U is turnedbm≥UcarrierWhen it is, the B-phase switch signal is OX, and when it is Ubm＜UcarrierWhen the phase B switching signal is XO; when U is turnedcm≥UcarrierWhen the phase C switching signal is OX, and when U iscm＜UcarrierWhen the phase C switching signal is XO;
in the second preset spaceCorner area and the sixth preset space corner area, when Uam≥UcarrierWhen the phase A switching signal is OX, and when U isam＜UcarrierWhen the phase A switching signal is XO; when U is turnedbm≥UcarrierWhen it is, the B-phase switch signal is OX, and when it is Ubm＜UcarrierWhen the phase B switching signal is XO; when U is turnedcm≥UcarrierWhen the phase C switching signal is XO, the phase U switching signal is set to XOcm＜UcarrierWhen the phase C switching signal is OX;
wherein, Uam、Ubm、UcmA-phase modulated wave, B-phase modulated wave and C-phase modulated wave, U, representing the three-phase modulated wavecarrierThe modulator represents a modulated carrier of an optimized carrier NSPWM, XO represents that an upper bridge arm switching device of a corresponding phase is turned off and a lower bridge arm switching device of the corresponding phase is turned on, and OX represents that the upper bridge arm switching device of the corresponding phase is turned on and the lower bridge arm switching device of the corresponding phase is turned off.
7. The NSPWM method according to claim 1, wherein the first predetermined value is-1 and the second predetermined value is 1.
8. An apparatus for optimizing carrier NSPWM of a two-level converter, comprising:
a three-phase modulation wave acquisition module for superposing a first specific voltage U on the three-phase sine wave in a first preset spatial angle region, a second preset angular region and a third preset spatial angle region1Superposing second specific voltage on the three-phase sine wave in a fourth preset space angle area, a fifth preset space angle area and a sixth preset space angle area to obtain a three-phase modulation wave of the optimized carrier NSPWM;
a modulated carrier obtaining module, configured to use a rising carrier with an initial value being a first preset value in the first preset spatial angle region, the second preset spatial angle region, and the third preset spatial angle region, and use a falling carrier with an initial value being a second preset value in the fourth preset spatial angle region, the fifth preset spatial angle region, and the sixth preset spatial angle region, so as to obtain a modulated carrier of an optimized carrier NSPWM;
and the switching signal acquisition module is used for comparing the three-phase modulation wave with the modulation carrier to obtain a switching signal of the optimized carrier NSPWM, so that the optimized carrier NSPWM is realized.
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120075892A1 (en) * 2010-09-29 2012-03-29 Rockwell Automation Technologies, Inc. Discontinuous pulse width drive modulation method and apparatus
JP2015023641A (en) * 2013-07-18 2015-02-02 株式会社日立製作所 Power conversion system and elevator
CN107786114A (en) * 2016-08-24 2018-03-09 申茂军 A kind of new PWM inverter topological structure
CN111064377A (en) * 2019-11-28 2020-04-24 中国科学院电工研究所 Synchronous carrier DPWM method for avoiding two-level jump of phase voltage of three-level inverter
CN112910283A (en) * 2021-03-09 2021-06-04 山东建筑大学 Method and system for simultaneously restraining common-mode voltage and circulating current of modular parallel rectifier

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120075892A1 (en) * 2010-09-29 2012-03-29 Rockwell Automation Technologies, Inc. Discontinuous pulse width drive modulation method and apparatus
JP2015023641A (en) * 2013-07-18 2015-02-02 株式会社日立製作所 Power conversion system and elevator
CN107786114A (en) * 2016-08-24 2018-03-09 申茂军 A kind of new PWM inverter topological structure
CN111064377A (en) * 2019-11-28 2020-04-24 中国科学院电工研究所 Synchronous carrier DPWM method for avoiding two-level jump of phase voltage of three-level inverter
CN112910283A (en) * 2021-03-09 2021-06-04 山东建筑大学 Method and system for simultaneously restraining common-mode voltage and circulating current of modular parallel rectifier

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
EMRE UN；AHMET M.HAVA: "A Near-State PWM Method With Reduced Switching Losses andReduced Common-Mode Voltage for Three-Phase Voltage Source Inverters", 2007 IEEE INTERNATIONAL ELECTRIC MACHINES & DRIVES CONFERENCE, no. 2007 *
姚文熙;王斯然;刘森森;吕征宇;: "三电平空间矢量调制中的共模分量", 电工技术学报, no. 04 *
章勇高;邝光健;龙立中;: "三相逆变器的无零矢量共模电压抑制技术研究", 电力***保护与控制, no. 02 *

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