CN107872167B - Virtual space vector modulation method for voltage type three-level neutral point clamped converter - Google Patents

Virtual space vector modulation method for voltage type three-level neutral point clamped converter Download PDF

Info

Publication number
CN107872167B
CN107872167B CN201711168906.4A CN201711168906A CN107872167B CN 107872167 B CN107872167 B CN 107872167B CN 201711168906 A CN201711168906 A CN 201711168906A CN 107872167 B CN107872167 B CN 107872167B
Authority
CN
China
Prior art keywords
vector
virtual
ref
level
reference voltage
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201711168906.4A
Other languages
Chinese (zh)
Other versions
CN107872167A (en
Inventor
李润秋
王燕
罗迪
施荣
李宁
邢琳
孙川永
焦熠琨
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
State Grid Corp of China SGCC
Xian Technological University
Economic and Technological Research Institute of State Grid Shaanxi Electric Power Co Ltd
Original Assignee
State Grid Corp of China SGCC
Xian Technological University
Economic and Technological Research Institute of State Grid Shaanxi Electric Power Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by State Grid Corp of China SGCC, Xian Technological University, Economic and Technological Research Institute of State Grid Shaanxi Electric Power Co Ltd filed Critical State Grid Corp of China SGCC
Priority to CN201711168906.4A priority Critical patent/CN107872167B/en
Publication of CN107872167A publication Critical patent/CN107872167A/en
Application granted granted Critical
Publication of CN107872167B publication Critical patent/CN107872167B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • H02M7/487—Neutral point clamped inverters
    • 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
    • H02M7/5387—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
    • H02M7/53876—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 based on synthesising a desired voltage vector via the selection of appropriate fundamental voltage vectors, and corresponding dwelling times

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)

Abstract

The invention discloses a virtual space vector modulation method of a voltage type three-level neutral point clamped converter, which comprises the following steps: forming a novel virtual vector space diagram of the three-level NPC converter; determining a reference voltage vector vrefWhether the current is in a first sector of a novel virtual vector space diagram of the three-level NPC current transformer; determining a reference voltage vector vrefThe triangle in which the triangle is located; according to a reference voltage vector vrefCalculating the action time of each virtual vector by the triangle; calculating the action time of each actual vector according to the action time of each virtual vector; calculating a switch state output sequence corresponding to the vector in each triangle according to the action time of each actual vector; the method comprises the steps of controlling the switching state of each switch in each phase of the voltage type three-level neutral point clamped converter according to the switching state output sequence corresponding to the vector in each triangle, and completing virtual space vector modulation of the voltage type three-level neutral point clamped converter.

Description

Virtual space vector modulation method for voltage type three-level neutral point clamped converter
Technical Field
The invention belongs to the field of power electronics, and relates to a virtual space vector modulation method, in particular to a virtual space vector modulation method of a voltage type three-level neutral point clamped converter.
Background
Compared with the traditional two-level converter, the three-level NPC converter has the advantages of high voltage level, large transmission power, small distortion rate of output waveform, low electromagnetic interference and the like, so that the three-level NPC converter is widely applied to various occasions such as electric energy quality analysis, direct-current transmission, superconducting energy storage, new energy generation and the like. However, the three-level NPC converter has the problems of unbalanced dc capacitor voltage and common mode voltage (current), and if the three-level NPC converter is not inhibited, the output characteristics of the three-level NPC converter are deteriorated if the three-level NPC converter is not inhibited, the harmonic on the inversion side is increased, and the system fault is caused if the three-level NPC converter is inhibited, so that the equipment and personal safety problems are caused.
In recent years, many researchers have studied on the problems of the dc capacitor voltage fluctuation and the common mode voltage of the three-level NPC converter, and some research results have been obtained. In the aspect of capacitance voltage fluctuation, some papers adopt a zero sequence component injection method to inject a zero sequence component into a reference voltage of a traditional modulation strategy, so that a certain effect is achieved; some papers reasonably allocate the action time of the redundant vector, so that the action time of the vector beneficial to the voltage balance of the direct current capacitor is as long as possible, and the unbalanced condition of the direct current capacitor voltage of the three-level NPC converter is improved to a certain extent. However, the above two methods cannot realize the dc capacitor voltage balance control of the full modulation degree and the full power factor, and the control effect in the high modulation degree and low power factor area is poor. Therefore, a scholars puts forward a virtual space vector modulation strategy, and the direct current capacitor voltage fluctuation control of the full modulation degree and the full power factor is well realized. In the aspect of common-mode voltage, some researchers propose corresponding common-mode voltage suppression strategies based on a three-level SPWM strategy and a three-level SVPWM strategy, but the direct-current capacitor voltage fluctuation control with full modulation degree and full power factor cannot be realized.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a virtual space vector modulation method of a voltage type three-level neutral point clamped converter, which can realize the voltage fluctuation control of a direct current capacitor with full modulation degree and full power factor.
In order to achieve the above purpose, the virtual space vector modulation method of the voltage type three-level midpoint clamping converter provided by the invention comprises the following steps:
1) obtaining a three-phase modulation wave according to a carrier PWM modulation method;
2) synthesis of a reference voltage vector v from a three-phase modulated waveref；
3) Constructing space vectors of a voltage type three-level neutral point clamped converter to obtain 27 space vectors;
4) constructing a plurality of virtual vectors according to the 27 space vectors obtained in the step 3), and then constructing a novel virtual vector space diagram of the three-level NPC converter according to the virtual vectors, wherein the novel virtual vector space diagram of the three-level NPC converter consists of six sectors, and each sector consists of five triangles constructed by the virtual vectors;
5) establishing a two-phase static coordinate system, and then obtaining a reference voltage vector v obtained in the step 2)refDecomposing the two-phase static coordinate system;
6) determining a reference voltage vector vrefWhether the reference voltage vector v is in the first sector of a novel virtual vector space diagram of the three-level NPC converterrefWhen the current transformer is not in the first sector of the novel virtual vector space diagram of the three-level NPC current transformer, the reference voltage vector v is converted into the reference voltage vector v by adopting a rotation methodrefMoving the current transformer to a first sector of a novel virtual vector space diagram of the three-level NPC current transformer;
7) determining a reference voltage vector vrefThe triangle in which the triangle is located;
8) according to a reference voltage vector vrefCalculating the action time of each virtual vector by the triangle;
9) calculating the action time of each actual vector according to the action time of each virtual vector;
10) calculating a switch state output sequence corresponding to the vector in each triangle according to the action time of each actual vector;
11) and controlling the switching state of each switch in each phase of the voltage type three-level neutral point clamped converter according to the switching state output sequence corresponding to the vector in each triangle to complete virtual space vector modulation of the voltage type three-level neutral point clamped converter.
The three-phase modulation wave in the step 1) is as follows:
Figure BDA0001476828550000031
where M is modulation degree, ω is fundamental angular frequency, t is time, UaIs an A-phase voltage, UbIs a B-phase voltage, UcIs C phase voltage;
reference voltage vector v in step 2)refComprises the following steps:
Figure BDA0001476828550000032
wherein,
Figure BDA0001476828550000033
the space vector V of the voltage type three-level midpoint clamping converter in the step 3) is as follows:
Figure BDA0001476828550000034
wherein, UdcIs the total voltage of the DC side, Sa、SbAnd ScThe switching states of the A phase, the B phase and the C phase of the voltage type three-level neutral point clamped converter are respectively.
The first sector of the novel virtual vector space diagram of the three-level NPC converter constructed in the step 4) is as follows:
Figure BDA0001476828550000041
wherein, VZ0Is a virtual zero vector, VZS1And VZS2As a virtual small vector, VZm1Is a virtual medium vector, VZl1And VZl2Is a virtual large vector.
Reference voltage vector vrefThe result of the decomposition on the two-phase stationary coordinate system is:
Figure BDA0001476828550000042
wherein q is a reference voltage vector vrefAngle, V, with α axes in a two-phase stationary frameαIs a reference voltage vector vrefComponent, V, on the α axis in a two-phase stationary frameβIs a reference voltage vector vrefThe component on the β axis in the two-phase stationary coordinate system.
Reference voltage vector vrefOn the nth sector of the novel virtual vector space diagram of the three-level NPC converter, wherein,
n＝ceil(q/60°) (6)
through Vα、VβAnd q value determination reference voltage vector vrefThe judgment basis of the triangle is as follows:
Figure BDA0001476828550000051
wherein, Va、VbBy UdcIs a per unit value, s1-s5Each representing 5 triangles.
According to a reference voltage vector vrefCalculating the action time of each virtual vector at the position of the triangle, wherein the action time of each virtual vector corresponding to each triangle in the first sector is respectively as follows:
Figure BDA0001476828550000052
Figure BDA0001476828550000053
and 9) calculating the action time of each actual vector according to the action time of each virtual vector, wherein the calculation formula is as follows:
Figure BDA0001476828550000054
the specific operation of step 10) is divided into two cases, wherein the first case is: when reference voltage vector vrefWhen the triangle is in the first sector, the output sequence of the switch state corresponding to the vector in each triangle is as follows:
s1:PON-OON-OPN-OPO-OOO-POO-PNO；
s2:PON-POO-PNO-ONO-OOO-OON-OPN；
s3:ONO-PNO-PNN-PON-POO-PON-OON-OPN；
s4:PNO-PNN-PON-PPN-OPN；
s5:OPO-OPN-OON-POO-PNO-POO-PON-PPN；
when reference voltage vector vrefWhen the triangle is not in the first sector, determining the switch state output sequence corresponding to the vector in each triangle according to the corresponding relation of the vector diagram, wherein the vector in the first case is replaced by the corresponding relation,
OOO: all sectors are the same;
POO ((a) — OON (2 sectors) -OPO (3 sectors) -NOO (4 sectors) -OOP (5 sectors) -ONO (6 sectors);
OON ((a)) -OPO (2 sector) -NOO (3 sector) -OOP (4 sector) -ONO (5 sector) -POO (6 sector);
ONO ((a)) -POO (2 sectors) -OON (3 sectors) -OPO (4 sectors) -NOO (5 sectors) -OOP (6 sectors);
OPO ((a) — NOO (2 sectors) -OOP (3 sectors) -ONO (4 sectors) -POO (5 sectors) -OON (6 sectors);
OPN ((a) — NPO (2 sector) -NOP (3 sector) -ONP (4 sector) -PNO (5 sector) -PON (6 sector);
PON ((a)) -OPN (2 sectors) -NPO (3 sectors) -NOP (4 sectors) -ONP (5 sectors) -PNO (6 sectors);
PNO ((a)) -PON (2 sector) -OPN (3 sector) -NPO (4 sector) -NOP (5 sector) -ONP (6 sector);
PNN (in (a) — PPN (2 sector) -NPN (3 sector) -NPP (4 sector) -NNP (5 sector) -PNP (6 sector);
PPN (in (a) — NPN (2 sector) -NPP (3 sector) -NNP (4 sector) -PNP (5 sector) -PNN (6 sector).
The specific operation of the step 11) is as follows: when the x-phase output state is P, the switch S1xAnd a switch S2xOn, switch S3xAnd a switch S4xWhen the X-phase output state is O, the switch S2xAnd a switch S3xOn, switch S1xAnd a switch S4xWhen the X-phase output state is N, the switch S is turned off3xAnd a switch S4xOn, switch S1xAnd a switch S2xAnd turning off, wherein x is a, b and c.
The invention has the following beneficial effects:
when the virtual space vector modulation method of the voltage type three-level neutral point clamped converter is operated, a plurality of virtual vectors are constructed through 27 space vectors, a novel virtual vector space diagram of the three-level NPC converter is constructed according to the virtual space vectors, and then each sector and a reference voltage vector v in the novel virtual vector space diagram of the three-level NPC converter are combined according to the virtual vector space diagramrefThe switching state output sequence is obtained according to the position relation, and finally the switching state of each switch in each phase on the voltage type three-level neutral point clamped converter is controlled according to the switching state output sequence.
Drawings
FIG. 1 is a main circuit topology diagram of a voltage type three-level neutral point clamped converter;
FIG. 2 is a voltage vector diagram of a conventional voltage-type three-level midpoint clamped current transformer;
FIG. 3 is a novel virtual vector space diagram of a voltage type three-level neutral point clamped converter;
FIG. 4 is a diagram of a division of triangles in a first sector of the present invention;
FIG. 5 is a diagram of simulation results of a voltage-type three-level midpoint clamping converter employing a conventional carrier modulation strategy and switching to the present invention;
FIG. 6a is a graph of the common mode voltage of the SPWM strategy;
FIG. 6b is a graph of the common mode voltage of a conventional VSVPM strategy;
FIG. 6c is a graph of the common mode voltage of the present invention.
Detailed Description
The invention is described in further detail below with reference to the accompanying drawings:
referring to fig. 1, 2, 3 and 4, the voltage type three-level midpoint clamping converter includes a three-phase ac part, a three-level dc side external part, a three-level NPC converter main circuit part, a voltage sensor, a current sensor, an AD conversion chip and a digital processor, where when the voltage type three-level midpoint clamping converter is a three-level inverter structure, the three-phase ac part is a load; when the voltage type three-level neutral point clamping converter is a three-level rectifier, a static var generator and the like, the three-phase alternating current part is an alternating current source and a three-phase alternating current smoothing reactor; when the voltage type three-level neutral point clamped converter is of a three-level inverter structure, the external part on the direct current side is a direct current voltage source; when the voltage type three-level neutral point clamped converter is of a three-level rectifier structure, the external part on the direct current side is a load; when the voltage type three-level neutral point clamping converter is a three-level static var generator, the direct current side has no external part; in addition, a voltage sensor detects the voltage of a three-phase alternating current part and the voltage of each capacitor on the direct current side; the current sensor detects the current of each phase at the AC side, the voltage sensor and the current sensor are connected with the digital processor through the AD conversion chip, and the digital processor controls the switch of each power device in the three-level converter through the driving circuit.
The virtual space vector modulation method of the voltage type three-level neutral point clamped converter comprises the following steps:
1) obtaining a three-phase modulation wave according to a carrier PWM modulation method;
2) synthesis of a reference voltage vector v from a three-phase modulated waveref；
3) Constructing space vectors of a voltage type three-level neutral point clamped converter to obtain 27 space vectors;
4) constructing virtual space vectors according to the 27 space vectors obtained in the step 3) to obtain a virtual zero vector, six virtual small vectors, six virtual medium vectors and six virtual large vectors, and then forming a novel virtual vector space diagram of the three-level NPC converter according to the virtual zero vector, the six virtual small vectors, the six virtual medium vectors and the six virtual large vectors, wherein the novel virtual vector space diagram of the three-level NPC converter consists of six sectors, and each sector consists of five triangles constructed by the virtual vectors;
5) establishing a two-phase static coordinate system, and then obtaining a reference voltage vector v obtained in the step 2)refDecomposing the two-phase static coordinate system;
6) determining a reference voltage vector vrefWhether the reference voltage vector v is in the first sector of a novel virtual vector space diagram of the three-level NPC converterrefWhen the current transformer is not in the first sector of the novel virtual vector space diagram of the three-level NPC current transformer, the reference voltage vector v is converted into the reference voltage vector v by adopting a rotation methodrefMoving the current transformer to a first sector of a novel virtual vector space diagram of the three-level NPC current transformer;
7) determining a reference voltage vector vrefThe triangle in which the triangle is located;
8) according to a reference voltage vector vrefCalculating the action time of each virtual vector by the triangle;
9) calculating the action time of each actual vector according to the action time of each virtual vector;
10) calculating an output sequence of the corresponding switch state of the vector in each triangle according to the action time of each actual vector;
11) and controlling the switching state of each switching tube in each phase of the voltage type three-level neutral point clamped converter according to the output sequence of the switching state corresponding to the vector in each triangle to complete the virtual space vector modulation of the voltage type three-level neutral point clamped converter.
In the step 1), the three-phase modulation wave is as follows:
Figure BDA0001476828550000101
where M is modulation degree, ω is fundamental angular frequency, t is time, UaIs an A-phase voltage, UbIs a B-phase voltage, UcIs C phase voltage;
reference voltage vector v in step 2)refComprises the following steps:
Figure BDA0001476828550000102
wherein,
Figure BDA0001476828550000103
the space vector V of the voltage type three-level midpoint clamping converter in the step 3) is as follows:
Figure BDA0001476828550000104
wherein, UdcIs the total voltage of the DC side, Sa、SbAnd ScThe switching states of the A phase, the B phase and the C phase of the voltage type three-level neutral point clamped converter are respectively.
The first sector of the virtual space vector constructed in step 4) is:
Figure BDA0001476828550000105
wherein, VZ0Is a virtual zero vector, VZS1And VZS2As a virtual small vector, VZm1Is a virtual medium vector, VZl1And VZl2Is a virtual large vector.
Reference voltage vector vrefThe result of the decomposition on the two-phase stationary coordinate system is:
Figure BDA0001476828550000111
wherein q is a reference voltage vector vrefAngle, V, with α axes in a two-phase stationary frameαIs a reference voltage vector vrefComponent, V, on the α axis in a two-phase stationary frameβIs a reference voltage vector vrefThe component on the β axis in the two-phase stationary coordinate system.
Reference voltage vector vrefIn the nth sector of the novel virtual vector space diagram of the three-level NPC converter, wherein,
n＝ceil(q/60°) (6)
wherein the ceil () function represents a rounding up, i.e., the first sector corresponds to qe (0-60), the second sector corresponds to qe (60-120), the third sector corresponds to qe (120-180), the fourth sector corresponds to qe (180-240), the fifth sector corresponds to qe (240-300), and the sixth sector corresponds to qe (300-360).
In addition, when the reference voltage vector vrefAnd when the current transformer is not in the first sector of the novel virtual vector space diagram of the three-level NPC current transformer, changing the included angle between the current transformer and the axis a, and setting the changed angle as q ', q' ═ q- (n-1) multiplied by 60.
Referring to FIG. 4, step 7) by Vα、VβAnd q value determination reference voltage vector vrefThe judgment basis of the triangle is as follows:
Figure BDA0001476828550000121
wherein, Va、VbBy UdcIs a per unit value, s1-s5Each representing 5 triangles.
In step 8) according to the reference voltage vector vrefCalculating the action time of each virtual vector at the position of the triangle, wherein the action time of each virtual vector corresponding to each triangle in the first sector is respectively as follows:
Figure BDA0001476828550000122
Figure BDA0001476828550000123
wherein, when the reference voltage vector is positioned in a No. 1 triangle in the first sector, the action time of each virtual vector is as follows:
Figure BDA0001476828550000124
the decomposition of the above formula on the a-axis and the b-axis respectively includes:
Figure BDA0001476828550000125
then there is
Figure BDA0001476828550000131
Solving the above equation to obtain:
Figure BDA0001476828550000132
and 9) calculating the action time of each actual vector according to the action time of each virtual vector, wherein the calculation formula is as follows:
Figure BDA0001476828550000133
the specific operation of step 10) is divided into two cases, wherein the first case is: when reference voltage vector vrefWhen the triangle is in the first sector, the output sequence of the switch state corresponding to the vector in each triangle is as follows:
s1:PON-OON-OPN-OPO-OOO-POO-PNO；
s2:PON-POO-PNO-ONO-OOO-OON-OPN；
s3:ONO-PNO-PNN-PON-POO-PON-OON-OPN；
s4:PNO-PNN-PON-PPN-OPN；
s5:OPO-OPN-OON-POO-PNO-POO-PON-PPN；
when reference voltage vector vrefWhen the triangle is not in the first sector, determining the output sequence of the switch states corresponding to the vectors in the triangles according to the corresponding relation of the vector diagram, wherein the vectors in the first case are replaced by the following corresponding relation,
OOO: all sectors are the same;
POO ((a) — OON (2 sectors) -OPO (3 sectors) -NOO (4 sectors) -OOP (5 sectors) -ONO (6 sectors);
OON ((a)) -OPO (2 sector) -NOO (3 sector) -OOP (4 sector) -ONO (5 sector) -POO (6 sector);
ONO ((a)) -POO (2 sectors) -OON (3 sectors) -OPO (4 sectors) -NOO (5 sectors) -OOP (6 sectors);
OPO ((a) — NOO (2 sectors) -OOP (3 sectors) -ONO (4 sectors) -POO (5 sectors) -OON (6 sectors);
OPN ((a) — NPO (2 sector) -NOP (3 sector) -ONP (4 sector) -PNO (5 sector) -PON (6 sector);
PON ((a)) -OPN (2 sectors) -NPO (3 sectors) -NOP (4 sectors) -ONP (5 sectors) -PNO (6 sectors);
PNO ((a)) -PON (2 sector) -OPN (3 sector) -NPO (4 sector) -NOP (5 sector) -ONP (6 sector);
PNN (in (a) — PPN (2 sector) -NPN (3 sector) -NPP (4 sector) -NNP (5 sector) -PNP (6 sector);
PPN (in (a) — NPN (2 sector) -NPP (3 sector) -NNP (4 sector) -PNP (5 sector) -PNN (6 sector).
The specific operation of the step 11) is as follows: when the x-phase output state is P, the switch S1xAnd a switch S2xOn, switch S3xAnd a switch S4xWhen the X-phase output state is O, the switch S2xAnd a switch S3xOn, switch S1xAnd a switch S4xWhen the X-phase output state is N, the switch S is turned off3xAnd a switch S4xOn, switch S1xAnd a switch S2xAnd turning off, wherein x is a, b and c.
The system shown in fig. 1 was simulated in Matlab/Simulink software, and the set basic parameters are shown in table 1:
TABLE 1
Figure BDA0001476828550000151
Obtaining simulation results in the graphs of fig. 5, fig. 6a, fig. 6B and fig. 6c by using Matlab/Simulink software according to the key parameters in table 1, wherein the initial time of the graph of fig. 5 adopts the traditional SPWM strategy, the graph is switched to the invention at 0.19s, and the simulation results are sequentially the output line voltages U of the phase a and the phase B from top to bottomabThree-phase output phase current IxCapacitor voltage U on the DC sidec1And Uc2As can be seen from fig. 5, when switching to the present invention, the low frequency fluctuation of the dc capacitor voltage is controlled to a small range around the equilibrium value.
From fig. 6, the maximum value of the common mode voltage of the conventional SPWM strategy and the virtual space vector modulation strategy is 133.3V (U)dc/3) and the common mode voltage of the present invention is 66.7V (U)dcAnd 6), the common-mode voltage is reduced by half compared with the traditional strategy, and a better effect of inhibiting the common-mode voltage is achieved.

Claims (9)

1. A virtual space vector modulation method of a voltage type three-level neutral point clamped converter is characterized by comprising the following steps:
1) obtaining a three-phase modulation wave according to a carrier PWM modulation method;
2) synthesis of a reference voltage vector v from a three-phase modulated waveref；
3) Constructing space vectors of a voltage type three-level neutral point clamped converter to obtain 27 space vectors;
4) constructing a plurality of virtual vectors according to the 27 space vectors obtained in the step 3), and then constructing a novel virtual vector space diagram of the three-level NPC converter according to the virtual vectors, wherein the novel virtual vector space diagram of the three-level NPC converter consists of six sectors, and each sector consists of five triangles constructed by the virtual vectors;
5) establishing a two-phase static coordinate system, and then obtaining a reference voltage vector v obtained in the step 2)refDecomposing the two-phase static coordinate system;
6) determining a reference voltage vector vrefWhether or not at three levelsIn a first sector of a novel virtual vector space diagram of the NPC converter, a reference voltage vector v is usedrefWhen the current transformer is not in the first sector of the novel virtual vector space diagram of the three-level NPC current transformer, the reference voltage vector v is converted into the reference voltage vector v by adopting a rotation methodrefMoving the current transformer to a first sector of a novel virtual vector space diagram of the three-level NPC current transformer;
7) determining a reference voltage vector vrefThe triangle in which the triangle is located;
8) according to a reference voltage vector vrefCalculating the action time of each virtual vector by the triangle;
9) calculating the action time of each actual vector according to the action time of each virtual vector;
10) calculating a switch state output sequence corresponding to the vector in each triangle according to the action time of each actual vector;
11) controlling the switching state of each switch in each phase of the voltage type three-level neutral point clamped converter according to the switching state output sequence corresponding to the vector in each triangle to complete virtual space vector modulation of the voltage type three-level neutral point clamped converter;
the first sector of the novel virtual vector space diagram of the three-level NPC converter constructed in the step 4) is as follows:
Figure FDA0002456136920000021
wherein, VZ0Is a virtual zero vector, VZS1And VZS2As a virtual small vector, VZm1Is a virtual medium vector, VZl1And VZl2As a virtual large vector, VOOO、VOON、VPOO、VONO、VOPO、VOPN、VPON、VPNO、VPPNAnd VPNNThe voltage vector of each sector in a novel virtual vector space diagram of the three-level NPC converter is obtained.
2. The virtual space vector modulation method of the voltage type three-level neutral point clamped converter according to claim 1, wherein the three-phase modulation wave in step 1) is:
Figure FDA0002456136920000022
where M is modulation degree, ω is fundamental angular frequency, t is time, UaIs an A-phase voltage, UbIs a B-phase voltage, UcIs C phase voltage;
reference voltage vector v in step 2)refComprises the following steps:
Figure FDA0002456136920000023
wherein,
Figure FDA0002456136920000024
the space vector V of the voltage type three-level midpoint clamping converter in the step 3) is as follows:
Figure FDA0002456136920000025
wherein, UdcIs the total voltage of the DC side, Sa、SbAnd ScThe switching states of the A phase, the B phase and the C phase of the voltage type three-level neutral point clamped converter are respectively.
3. The virtual space vector modulation method of the voltage type three-level midpoint clamped current transformer of claim 2, characterized in that a reference voltage vector v is modulatedrefThe result of the decomposition on the two-phase stationary coordinate system is:
Figure FDA0002456136920000031
wherein q is a reference voltage vector vrefAngle, V, with α axes in a two-phase stationary frameαIs a reference voltage vector vrefComponent, V, on the α axis in a two-phase stationary frameβIs a reference voltage vector vrefThe component on the β axis in the two-phase stationary coordinate system.
4. The virtual space vector modulation method of the voltage type three-level midpoint clamped current transformer of claim 3, wherein the reference voltage vector v isrefOn the nth sector of the novel virtual vector space diagram of the three-level NPC converter, wherein,
n＝ceil(q/60°) (6)。
5. the virtual space vector modulation method of a voltage-type three-level midpoint clamped current transformer as claimed in claim 4, wherein V is passedα、VβAnd q value determination reference voltage vector vrefThe judgment basis of the triangle is as follows:
Figure FDA0002456136920000032
wherein, Va、VbBy UdcIs a per unit value, s1-s5Each representing 5 triangles.
6. The virtual space vector modulation method of the voltage type three-level midpoint clamped current transformer of claim 5, wherein the virtual space vector modulation method is based on a reference voltage vector vrefCalculating the action time of each virtual vector at the position of the triangle, wherein the action time of each virtual vector corresponding to each triangle in the first sector is respectively as follows:
Figure FDA0002456136920000041
Figure FDA0002456136920000042
7. the virtual space vector modulation method of the voltage type three-level midpoint clamping current transformer according to claim 6, wherein the action time of each actual vector is calculated according to the action time of each virtual vector in step 9), wherein the calculation formula is as follows:
Figure FDA0002456136920000043
8. the virtual space vector modulation method of the voltage type three-level neutral point clamped converter according to claim 1, wherein the specific operation of step 10) is divided into two cases, wherein the first case is: when reference voltage vector vrefWhen the triangle is in the first sector, the output sequence of the switch state corresponding to the vector in each triangle is as follows:
s1:PON-OON-OPN-OPO-OOO-POO-PNO；
s2:PON-POO-PNO-ONO-OOO-OON-OPN；
s3:ONO-PNO-PNN-PON-POO-PON-OON-OPN；
s4:PNO-PNN-PON-PPN-OPN；
s5:OPO-OPN-OON-POO-PNO-POO-PON-PPN；
when reference voltage vector vrefWhen the triangle is not in the first sector, determining the switch state output sequence corresponding to the vector in each triangle according to the corresponding relation of the vector diagram, wherein the vector in the first case is replaced by the corresponding relation,
OOO: all sectors are the same;
POO a-OON-OPO-NOO-OOP-ONO;
OON a-OPO-NOO-OOP-ONO-POO;
ONO medium-POO-OON-OPO-NOO-OOP;
OPO a-NOO-OOP-ONO-POO-OON;
OPN a medium-NPO-NOP-ONP-PNO-PON;
OPN-NPO-NOP-ONP-PNO in PON a;
PNO a-PON-OPN-NPO-NOP-ONP;
PNN a-PPN-NPN-NPP-NNP-PNP;
PPN a is NPN-NPP-NNP-PNP-PNN.
9. The virtual space vector modulation method of the voltage type three-level midpoint clamped current transformer according to claim 1, wherein the specific operations of step 11) are as follows: when the x-phase output state is P, the switch S1xAnd a switch S2xOn, switch S3xAnd a switch S4xWhen the X-phase output state is O, the switch S2xAnd a switch S3xOn, switch S1xAnd a switch S4xWhen the X-phase output state is N, the switch S is turned off3xAnd a switch S4xOn, switch S1xAnd a switch S2xAnd turning off, wherein x is a, b and c.
CN201711168906.4A 2017-11-21 2017-11-21 Virtual space vector modulation method for voltage type three-level neutral point clamped converter Active CN107872167B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201711168906.4A CN107872167B (en) 2017-11-21 2017-11-21 Virtual space vector modulation method for voltage type three-level neutral point clamped converter

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201711168906.4A CN107872167B (en) 2017-11-21 2017-11-21 Virtual space vector modulation method for voltage type three-level neutral point clamped converter

Publications (2)

Publication Number Publication Date
CN107872167A CN107872167A (en) 2018-04-03
CN107872167B true CN107872167B (en) 2020-06-09

Family

ID=61754356

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201711168906.4A Active CN107872167B (en) 2017-11-21 2017-11-21 Virtual space vector modulation method for voltage type three-level neutral point clamped converter

Country Status (1)

Country Link
CN (1) CN107872167B (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108696166A (en) * 2018-06-20 2018-10-23 合肥工业大学 A kind of Virtual Space Vector Pulse Width Modulation method of three-level current transformer
JP7053903B2 (en) * 2019-02-14 2022-04-12 三菱電機株式会社 Power converter
CN110112945B (en) * 2019-04-28 2020-07-10 华中科技大学 Method and system for neutral point voltage control and common mode voltage suppression of three-level inverter
CN111181429B (en) * 2020-01-09 2023-06-13 东北农业大学 Balancing method and system for neutral point voltage of three-level inverter based on three partitions
CN111293915B (en) * 2020-02-29 2023-03-31 天津工业大学 Improved virtual vector modulation method for NPC inverter under neutral point potential imbalance

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105226981A (en) * 2015-10-26 2016-01-06 中国矿业大学 A kind of space vector modulating method with neutral-point-potential balance control
CN106533226A (en) * 2015-09-09 2017-03-22 上海三菱电梯有限公司 Neutral-point voltage balance control method of three-level converter

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6534949B2 (en) * 2001-03-29 2003-03-18 General Electric Company Motor drive converter and method with neutral point drift compensation

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106533226A (en) * 2015-09-09 2017-03-22 上海三菱电梯有限公司 Neutral-point voltage balance control method of three-level converter
CN105226981A (en) * 2015-10-26 2016-01-06 中国矿业大学 A kind of space vector modulating method with neutral-point-potential balance control

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
三电平NPC 变流器虚拟空间矢量调制策略与载波调制策略的内在关系研究;李宁等;《电网技术》;20140131;第38卷(第1期);第166-174页 *

Also Published As

Publication number Publication date
CN107872167A (en) 2018-04-03

Similar Documents

Publication Publication Date Title
CN107872167B (en) Virtual space vector modulation method for voltage type three-level neutral point clamped converter
Dai et al. Application of a three-level NPC inverter as a three-phase four-wire power quality compensator by generalized 3DSVM
CN105305863B (en) A kind of three level NPC inverter neutral-point potential balance control methods
CN108768196A (en) A kind of modulation of novel three level NPC current transformers and neutral point voltage control strategy
CN111293915B (en) Improved virtual vector modulation method for NPC inverter under neutral point potential imbalance
CN108683349B (en) Double-space vector modulation method for three-level direct matrix converter
CN110557039A (en) inverter control device
CN111064377B (en) Synchronous carrier DPWM method for avoiding two-level jump of phase voltage of three-level inverter
CN115133798A (en) Discrete space vector modulation three-level inverter low common mode prediction control method
CN111416540A (en) Multi-level converter midpoint potential rapid balance control system and method
CN113783456A (en) Low common mode vector modulation method and system of three-level SNPC inverter
CN113746108B (en) T-type three-level SAPF open circuit fault sequence model prediction fault tolerance control method
Pinkymol et al. Analysis of 3-level inverter scheme with DC-link voltage balancing using LS-PWM & SVM techniques
Waware et al. A review of multilevel inverter based active power filter
CN111030497B (en) Three-phase four-leg inverter parallel system, control method thereof and electric energy management equipment
CN117277764A (en) Carrier optimized three-level inverter intermittent pulse width modulation method and system
CN109256972B (en) SVPWM modulation method based on five-segment five-level converter
Li et al. A general SVM algorithm for multilevel converters considering zero-sequence component control
CN115459621A (en) Space vector modulation method and system of asymmetric quasi-Z-source three-level inverter
CN114649967A (en) Pre-stage T-type three-level PFC performance optimization modulation method and system of charging system
Solemanifard et al. A commutation method free from inrush current for the carrier-based PWM controlled direct matrix converter
Menshawi et al. Multistage inverters control using surface hysteresis comparators
Xiong et al. Algebraic Modulation Strategy for Direct Matrix Converter With Adaptation to Unbalanced Grids
CN108832828A (en) A kind of modulation strategy of three level NPC current transformer
Lin et al. Multilevel AC/DC/AC converter by using three-level boost rectifier and five-level diode clamped inverter

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant