CN114301321A - Hysteresis loop SVPWM reconfigurable fault-tolerant control method for single-phase voltage source multi-level inverter - Google Patents

Hysteresis loop SVPWM reconfigurable fault-tolerant control method for single-phase voltage source multi-level inverter Download PDF

Info

Publication number
CN114301321A
CN114301321A CN202111657214.2A CN202111657214A CN114301321A CN 114301321 A CN114301321 A CN 114301321A CN 202111657214 A CN202111657214 A CN 202111657214A CN 114301321 A CN114301321 A CN 114301321A
Authority
CN
China
Prior art keywords
fault
inverter
voltage vector
vector
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.)
Granted
Application number
CN202111657214.2A
Other languages
Chinese (zh)
Other versions
CN114301321B (en
Inventor
李国华
邬泽华
赵子奇
李嘉祥
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.)
Liaoning Technical University
Original Assignee
Liaoning Technical University
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 Liaoning Technical University filed Critical Liaoning Technical University
Priority to CN202111657214.2A priority Critical patent/CN114301321B/en
Publication of CN114301321A publication Critical patent/CN114301321A/en
Application granted granted Critical
Publication of CN114301321B publication Critical patent/CN114301321B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Abstract

The invention provides a hysteresis loop SVPWM reconfigurable fault-tolerant control method of a single-phase voltage source multilevel inverter, and relates to the technical field of power transmission and distribution. Firstly, constructing a single-phase multi-level voltage source inverter, and controlling the tracking error of the inverter within a hysteresis range; when the voltage vector selected by the current tracking control algorithm in the non-fault state before the fault occurs is a non-fault vector, the voltage vector is the final output vector of the inverter; when the selected voltage vector is a fault vector, performing voltage vector substitution; according to the current tracking error, preferentially selecting a redundant voltage vector overlapped at a position for equivalent substitution; if no redundant voltage vector with coincident position exists, other non-fault vectors with the closest position and action effect are selected to control the actual output current of the inverter to rise and fall, so that the reference current is tracked, and the fault-tolerant control is realized. The method can ensure the inverter to continuously and stably work under the condition of single-tube and most double-tube open-circuit faults of the inverter.

Description

Hysteresis loop SVPWM reconfigurable fault-tolerant control method for single-phase voltage source multi-level inverter
Technical Field
The invention relates to the technical field of power transmission and distribution, in particular to a hysteresis loop SVPWM reconfigurable fault-tolerant control method of a single-phase voltage source multi-level inverter.
Background
The current tracking type multi-level inverter is widely applied to occasions such as photovoltaic grid connection, active filtering and reactive compensation of a medium-high voltage power system and the like; with the development of technologies such as solar cells and the like and the reduction of cost, the multi-level inverter structure adopting a plurality of independent direct-current power supplies has the characteristic of high economical efficiency; the increase of the number of the levels is beneficial to improving the output voltage level of the inverter and accords with the popular design concept of silicon copper feeding and copper discharging at present.
However, since the number of power switches in a multilevel inverter is relatively large, the probability of failure is also much greater. Once a fault occurs, if fault-tolerant control is not adopted, a large impact is caused to the power grid and the load.
Fault-tolerant control methods of a multilevel inverter can be classified into hardware method and software method 2. The hardware approach generally requires adding spare cells or other auxiliary modules in the multilevel inverter topology, on the basis of which fault-tolerant control is implemented. The document "configurable multilevel inverter with fault-tolerant ability" adds an additional module on the load side of the cascade inverter, and the structure can be flexibly reconfigured according to different fault modes to realize fault tolerance.
The software method does not need to change the topological structure of the multi-level inverter, but realizes fault-tolerant control through a control algorithm; hardware cost can be saved, and the system structure is simplified. Mainly comprises the following 3 types:
one is to shield the faulty unit and operate at reduced capacity. The method is suitable for cascading inverters. In order to ensure symmetry of the three-phase output voltages, in addition to the short-circuited faulty cells, the non-faulty cells corresponding to the faulty cells in the other two phases are usually also shielded. Therefore, part of non-fault units cannot be fully utilized, and the waste of hardware resources exists. The document "A new fault-tolerant base on a modified selected harmonic technical for a three-phase multilevel converter with a single fault cell" takes a seven-level cascade inverter as an example to prove that the type of the converter is the same as the one of the seven-level cascade inverterIn the fault-tolerant method, the amplitude of the voltage of the output line of the inverter is changed from 5.19V before the faultdcDown to 3.46V after failuredcIn which V isdcIs the DC side voltage of the cascade unit.
The neutral point offset method is essentially to inject a basic zero sequence voltage, and the method can obtain the maximum symmetrical line voltage under the condition of only bypassing a fault unit; the neutral shift method is liable to cause a rise in low-order voltage harmonics. The document "Control Method for shielded H-Bridge Inverter With fault Cells Based on Differential PWM" proposes a Differential modulation mode, which can reduce the voltage harmonic caused by neutral shift while realizing fault-tolerant operation. However, when the load power factor is low, the injected zero sequence voltage may cause the actual power to flow back, causing the dc side voltage to rise and even exceed the set range.
And thirdly, adjusting the voltage value of the direct current side of the inverter. The document "Fault-Tolerant Design and Control Strategy for Cascaded H-Bridge Multilevel Converter-Based STATCOM" makes the maximum value of the output voltage of the phase same as that before the Fault by increasing the DC side voltage of the Cascaded unit in the Fault phase; the document "A new fault-tolerant string for a clamped H-bridge based STATCOM" raises the DC side voltage of the fault phase of the inverter to 2N/(2N-1) times, and an improved SHEPWM method is adopted, so that fault-tolerant operation is realized, and low-order voltage harmonics can be selectively eliminated. However, the fault-tolerant method is only suitable for occasions with controllable direct-current voltage; but also results in increased voltage stress of the power electronics. Therefore, documents of 'Fault-tolerant operation of a base-energy-storage system base on a multi-level cassette PWM converter with a stage configuration' and 'A Fault-tolerant strand base on fundamental phase-shift compensation for a neutral-phase multi-level converters with a quadrature-Z-source networks with a discrete input current' propose a Fault-tolerant control method combining neutral point shift and DC-side voltage adjustment, which can reduce the voltage stress borne by the power electronic device in a Fault state. In the method, the spatial position of the voltage vector is changed due to the rise of the voltage on the direct current side of the inverter, so that the selection algorithm of the voltage vector becomes more complex.
Disclosure of Invention
The invention aims to solve the technical problem of the prior art, and provides a hysteresis loop SVPWM reconfigurable fault-tolerant control method of a single-phase voltage source multilevel inverter, which is used for realizing fault-tolerant control of the single-phase voltage source multilevel inverter.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows: the single-phase voltage source multi-level inverter hysteresis SVPWM reconfigurable fault-tolerant control method comprises the following steps:
step 1, constructing a single-phase multi-level voltage source inverter;
the single-phase multi-level voltage source inverter consists of 2 independent direct current power supplies and 9 groups of power switching devices T1-T9Composition is carried out; wherein, 3 groups of switching devices T5、T8And T9Adopting a single-phase bridge type uncontrollable rectifying module, and arranging an IGBT on the direct current side of a rectifying bridge; the inverter switching states and voltage space vectors are shown in Table 1, where uABOutputting phase voltage for the inverter, and E is direct current power supply voltage; the inverter has 17 switching states and voltage space vectors, and outputs 7 levels of 3E, 2E, E, 0, -E, -2E and-3E;
TABLE 1 inverter switching State and Voltage vector
Figure BDA0003446276610000021
Figure BDA0003446276610000031
Step 2, controlling the tracking error of the inverter within a hysteresis range;
firstly, determining the current tracking error delta i-i of the inverter by using hysteresis loop comparison*-i, wherein i*Is the reference current, i is the actual current; then, the tracking error is reduced to be within a hysteresis range by reasonably selecting the voltage vector of the inverter; third order hysteresis widthH, 2h and 3h respectively; the voltage vector selection method under the non-fault state is shown in table 2; in a fault state, equivalent substitution is required to be carried out on a voltage vector selected by a current tracking control algorithm in a non-fault state, namely fault-tolerant control is carried out;
respectively selecting voltage space vector V under non-fault state1、V4、V5、V6、V13、V14And V15To generate 3E, 2E, E, 0, -E, -2E, -3E 7 levels; that is, only 1 inverter switching state is reserved for each level; at this time, the switching device T6And T7Only participate in the work during fault-tolerant control;
TABLE 2 hysteresis control method in non-failure state
Tracking error Voltage vector uAB
△i＞3h V15～V 17 3E
2h＜△i≤3h V 14 2E
h＜△i≤2h V13 E
-h≤△i≤h V6～V12 0
-2h≤△i＜-h V5 -E
-3h≤△i＜-2h V4 -2E
△i＜-3h V1～V3 -3E
When one or more IGBTs in the inverter have an open-circuit fault, some voltage vectors are affected by the fault and become fault vectors, as shown in table 3, wherein √ indicates that the fault has no effect on the voltage vector; "x" indicates an influence, that is, the voltage vector becomes a fault vector;
TABLE 3 Effect of single tube open-circuit Fault on inverter
Vector T1 T2 T3 T4 T5 T6 T7 T8 T9 uAB
V1 √ × × √ √ √ √ √ √ -3E
V2 √ √ × √ √ × √ √ × -3E
V3 √ × √ √ √ √ × × √ -3E
V4 √ × √ √ × √ √ × √ -2E
V5 √ √ × √ × √ √ √ × -E
V6 × × √ √ √ √ √ √ √ 0
V7 √ √ × × √ √ √ √ √ 0
V8 × √ √ √ √ × √ √ × 0
V9 √ √ × √ √ √ × √ × 0
V10 √ × √ √ √ × √ × √ 0
V11 √ √ √ × √ √ × × √ 0
V12 √ √ √ √ √ √ √ × × 0
V13 √ √ √ × × √ √ × √ E
V14 × √ √ √ × √ √ √ × 2E
V15 × √ √ × √ √ √ √ √ 3E
V16 × √ √ √ √ √ × √ × 3E
V17 √ √ √ × √ × √ × √ 3E
Step 3, when the voltage vector selected by the current tracking control algorithm in the non-fault state before the fault occurs is a non-fault vector, the voltage vector is the final output vector of the inverter; when the selected voltage vector is a fault vector, voltage vector substitution is required;
(1) replacing a voltage vector of the inverter under the condition of single-tube open circuit fault;
in the voltage vectors selected by the current tracking control algorithm in the non-fault state, the voltage vectors which are not affected by the fault are continuously used without replacement; if the voltage vector affected by the fault has the voltage vector with the same level value as the voltage vector, the voltage vector with the same level value is used for equivalent substitution, and the output levels of the inverters before and after substitution are the same; if no voltage vector with the same level value can be selected, selecting the vector with the same level direction and the size smaller than the set threshold value for substitution; namely, when h is less than or equal to 2h and 2h is less than or equal to 3h, the vector V is selected13(ii) a Or when 2h is less than or equal to 3h and delta i is more than 3h, selecting the vector V17；
(2) Replacing a voltage vector of the inverter under the condition of double-tube open circuit fault;
when the inverter has double-tube open-circuit fault, at least 1 positive level, zero level and negative level can be output, and fault-tolerant control is performed through voltage vector substitution; when the inverter has a double-tube open-circuit fault, if the output end lacks a positive level or a negative level, the fault-tolerant control cannot be realized through inverter topology structure reconstruction and voltage vector replacement, and then step 4 is executed;
step 4, hysteresis SVPWM reconfigurable fault-tolerant control is carried out; reasonably selecting an effective voltage vector according to the current tracking error, and preferentially selecting a redundant voltage vector with coincident positions for equivalent substitution; if no redundant voltage vector with coincident position exists, other non-fault vectors with the closest position and action effect are selected to control the actual output current of the inverter to rise and fall, so that the reference current is tracked, and the fault-tolerant control is realized.
When the voltage vector selected by the current tracking control algorithm in the non-fault state before the fault occurs is a non-fault vector, the voltage vector is the final output vector of the inverter; when the selected voltage vector is a fault vector, voltage vector substitution is required; the voltage vector substitution method under the single-tube open circuit and double-tube open circuit faults of the inverter is shown in tables 4-5;
TABLE 4 inverter Voltage vector substitution table under single tube open circuit fault
Figure BDA0003446276610000051
TABLE 5 inverter Voltage vector substitution representation under two-transistor open-circuit Fault
Figure BDA0003446276610000052
Figure BDA0003446276610000061
Wherein, the single tube open circuit fault comprises 9 types, and the double tube open circuit fault comprises 36 types; "√" indicates that the fault has no effect on the voltage vector and does not need to be replaced; in table 5, the case of "none" is "when the inverter has a double-tube open-circuit fault, if the output terminal lacks a positive level or lacks a negative level, the fault-tolerant control cannot be realized through inverter topology reconstruction and voltage vector replacement.
Adopt the produced beneficial effect of above-mentioned technical scheme to lie in: the hysteresis SVPWM reconfigurable fault-tolerant control method of the single-phase voltage source multilevel inverter provided by the invention combines the advantages of hardware and software fault-tolerant control methods, and realizes fault-tolerant control by using a method of topological structure reconfiguration and redundant voltage vector equivalent substitution when single-tube and double-tube power failure occurs. The method preferentially selects the redundant voltage vector with coincident positions to carry out equivalent substitution, and if no coincident vector exists, other vectors with the positions and the action effects closest to each other are selected, so that fault-tolerant control is realized. The method can ensure the inverter to continuously and stably work under the condition of single-tube and most double-tube open-circuit faults of the inverter, and can accurately track the reference current value. The fault-tolerant method does not need the switching operation of the main and standby switching device units of the inverter, can save additional switching devices required in the switching process, and has the advantages of simple operation and high stability.
Drawings
Fig. 1 is a structural topology diagram of a main circuit of a single-phase multilevel voltage source inverter according to an embodiment of the present invention;
FIG. 2 shows the normal and T of each switch provided by the embodiment of the present invention1The influence on the voltage vector in open circuit fault is shown in the figure, wherein (a) is that each switch is normal, and (b) is T1Open circuit failure;
fig. 3 is a block diagram of a hysteresis current tracking control method of an inverter according to an embodiment of the present invention;
FIG. 4 shows a diagram of T according to an embodiment of the present invention2And T3The effect of open circuit fault on voltage vector is shown in the figure, wherein (a) is T2Open circuit failure, (b) is T3Open circuit failure;
FIG. 5 shows a diagram of T according to an embodiment of the present invention4And T5The effect of open circuit fault on voltage vector is shown in the figure, wherein (a) is T4Open circuit failure, (b) is T5Open circuit failure;
FIG. 6 shows a graph T according to an embodiment of the present invention6And T7The effect of open circuit fault on voltage vector is shown in the figure, wherein (a) is T6Open circuit failure, (b) is T7Open circuit failure;
FIG. 7 shows a graph T according to an embodiment of the present invention8And T9The effect of open circuit fault on voltage vector is shown in the figure, wherein (a) is T8Open circuit failure, (b) is T9Open circuit failure;
FIG. 8 shows a graph of T according to an embodiment of the present invention1And T2、T1And T7The influence on the voltage vector in the case of a fault is shown in the figure, wherein (a) is T1And T2Open circuit simultaneous failure, (b) is T1And T7Open circuit simultaneous failure;
FIG. 9 shows a diagram of T according to an embodiment of the present invention4And T5、T4And T8The influence on the voltage vector in the case of a fault is shown in the figure, wherein (a) is T4And T5Open circuit simultaneous failure, (b) is T4And T8Open circuit simultaneous failure;
FIG. 10 is a waveform diagram of voltage and current when the switch tube is normal according to the embodiment of the present invention;
FIG. 11 is a diagram of the current THD during normal operation according to an embodiment of the present invention;
FIG. 12 shows a graph of T according to an embodiment of the present invention1Voltage and current waveform diagrams during fault;
FIG. 13 shows a graph of T according to an embodiment of the present invention1A current at fault THD plot;
FIG. 14 shows a graph of T according to an embodiment of the present invention1Voltage and current oscillograms after fault tolerance;
FIG. 15 shows a graph of T according to an embodiment of the present invention1A fault-tolerant current THD graph;
FIG. 16 shows a graph of T according to an embodiment of the present invention5Voltage and current oscillograms after fault tolerance;
FIG. 17 is a drawing of a graph T according to an embodiment of the present invention5A fault-tolerant current THD graph;
FIG. 18 shows a graph of T according to an embodiment of the present invention1And T2Meanwhile, a voltage and current oscillogram after fault tolerance of the fault is obtained;
FIG. 19 shows a graph of T according to an embodiment of the present invention1And T2Meanwhile, a voltage and current oscillogram after fault tolerance of the fault is obtained;
FIG. 20 shows a graph of T according to an embodiment of the present invention1And T2Meanwhile, a fault-tolerant current THD graph is obtained;
FIG. 21 shows a graph of T according to an embodiment of the present invention4And T5Meanwhile, a voltage and current oscillogram after fault tolerance of the fault is obtained;
FIG. 22 shows a graph of T according to an embodiment of the present invention4And T5And meanwhile, a fault-tolerant current THD diagram is obtained.
Detailed Description
The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.
In this embodiment, the single-phase voltage source multilevel inverter hysteresis loop SVPWM reconfigurable fault-tolerant control method includes the following steps:
step 1, constructing a single-phase multi-level voltage source inverter;
in this embodiment, as shown in fig. 1, the single-phase multilevel voltage source inverter includes 2 independent dc power sources and 9 groups of power switching devices T1-T9And (4) forming. Wherein, 3 groups of switching devices T5、T8And T9A common single-phase bridge type uncontrollable rectification module is adopted, and an IGBT is arranged on the direct current side of a rectification bridge; the inverter switching states and voltage space vectors are shown in Table 1, where uABOutputting phase voltage for the inverter, and E is direct current power supply voltage; the space position of the voltage vector is shown in figure 2(a), the inverter has 17 switch states and voltage space vectors, and outputs 7 levels of 3E, 2E, E, 0, -E, -2E and 3E; under the fault state, the redundant voltage vector can be generated through the reconstruction of the topological structure, and a foundation is laid for a fault-tolerant control algorithm.
TABLE 1 inverter switching State and Voltage vector
Figure BDA0003446276610000071
Figure BDA0003446276610000081
Step 2, controlling the tracking error of the inverter within a hysteresis range;
in the present embodiment, as shown in fig. 3, the inverter hysteresis current tracking control first determines the inverter current tracking error Δ i ═ i using hysteresis comparison*-i, wherein i*Is the reference current, i is the actual current; then, the tracking error is reduced to be within a hysteresis range by reasonably selecting the voltage vector of the inverter; the widths of the third-order hysteresis loops are h, 2h and 3h respectively; the voltage vector selection method under the non-fault state is shown in table 2; in a fault state, equivalent substitution is required to be carried out on a voltage vector selected by a current tracking control algorithm in a non-fault state, namely fault-tolerant control is carried out;
to simplify the algorithm, the voltage space vectors V are selected in the non-fault state1、V4、V5、V6、V13、V14And V15To generate 3E, 2E, E, 0, -E, -2E, -3E 7 levels; that is, only 1 inverter switching state is reserved for each level; at this time, the switching device T6And T7Only participate in the work during fault-tolerant control;
TABLE 2 hysteresis control method in non-failure state
Figure BDA0003446276610000082
Figure BDA0003446276610000091
When one or more IGBTs in the inverter have open-circuit faults, some voltage vectors are influenced by the faults and become fault vectors; as shown in table 3, where "√" indicates that a fault has no effect on the voltage vector; "x" indicates an influence, that is, the voltage vector becomes a fault vector;
as can be seen from Table 3, when T is1～T9When 1 of the inverters has an open-circuit fault, the inverters can output at least 1 positive level, zero level and negative level; that is, theoretically, the load current can still be controlled to rise and fall, and only the number of the selectable voltage vectors and the number of the output levels are reduced;
fig. 2(b) and fig. 4-7 show the spatial distribution diagram of the inverter voltage vector under the single tube open fault. FIGS. 8 and 9 are at T1And T2、T1And T7、T4And T5、T4And T8Failure is exemplified by a dual tube open circuit failure analysis. Wherein, the dotted line represents a fault vector, and voltage vector replacement is required; the solid line represents a non-fault vector and no voltage vector replacement is required.
TABLE 3 Effect of single tube open-circuit Fault on inverter
Vector T1 T2 T3 T4 T5 T6 T7 T8 T9 uAB
V1 √ × × √ √ √ √ √ √ -3E
V2 √ √ × √ √ × √ √ × -3E
V3 √ × √ √ √ √ × × √ -3E
V4 √ × √ √ × √ √ × √ -2E
V5 √ √ × √ × √ √ √ × -E
V6 × × √ √ √ √ √ √ √ 0
V7 √ √ × × √ √ √ √ √ 0
V8 × √ √ √ √ × √ √ × 0
V9 √ √ × √ √ √ × √ × 0
V10 √ × √ √ √ × √ × √ 0
V11 √ √ √ × √ √ × × √ 0
V12 √ √ √ √ √ √ √ × × 0
V13 √ √ √ × × √ √ × √ E
V14 × √ √ √ × √ √ √ × 2E
V15 × √ √ × √ √ √ √ √ 3E
V16 × √ √ √ √ √ × √ × 3E
V17 √ √ √ × √ × √ × √ 3E
Step 3, when the voltage vector selected by the current tracking control algorithm in the non-fault state before the fault occurs is a non-fault vector, the voltage vector is the final output vector of the inverter; when the selected voltage vector is a fault vector, voltage vector substitution is required;
(1) replacing a voltage vector of the inverter under the condition of single-tube open circuit fault;
in the voltage vectors selected by the current tracking control algorithm in the non-fault state, the voltage vectors which are not affected by the fault are continuously used without replacement; if the voltage vector affected by the fault has the voltage vector with the same level value as the voltage vector, the voltage vector with the same level value is used for equivalent substitution, and the output levels of the inverters before and after substitution are the same; if no voltage vector with the same level value can be selected, selecting the vector with the same level direction and the size smaller than the set threshold value for substitution; namely, when h is less than or equal to 2h and 2h is less than or equal to 3h, the vector V is selected13(ii) a Or when 2h is less than or equal to 3h and delta i is more than 3h, selecting the vector V17。
(2) Replacing a voltage vector of the inverter under the condition of double-tube open circuit fault;
when the inverter has double-tube open-circuit fault, at least 1 positive level, zero level and negative level can be output, and fault-tolerant control is performed through voltage vector substitution; when the inverter has a double-tube open-circuit fault, if the output end lacks a positive level or a negative level, the fault-tolerant control cannot be realized through inverter topology structure reconstruction and voltage vector replacement, and then step 4 is executed;
step 4, hysteresis SVPWM reconfigurable fault-tolerant control is carried out; reasonably selecting an effective voltage vector according to the current tracking error, and preferentially selecting a redundant voltage vector with coincident positions for equivalent substitution; if no coincident non-fault vector exists, other non-fault vectors with the positions and the action effects closest to each other are selected, and the actual output current of the inverter is controlled to rise and fall, so that the reference current is tracked, and the fault-tolerant control is realized.
As shown in fig. 2(a) and table 3, when the voltage vector selected by the current tracking control algorithm in the non-fault state before the fault occurs is a non-fault vector, the voltage vector is the final output vector of the inverter; when the selected voltage vector is a fault vector, voltage vector replacement is required. Tables 4-5 show the voltage vector substitution method under the single-tube open circuit and double-tube open circuit faults of the inverter; wherein, the single tube open circuit fault comprises 9 types, and the double tube open circuit fault comprises 36 types; "√" indicates that the fault has no effect on the voltage vector and does not require replacement. In the table, the case of "none" is that "when the inverter has a double-tube open-circuit fault, if the output end lacks a positive level or lacks a negative level, fault-tolerant control cannot be realized through inverter topology reconstruction and voltage vector replacement.
TABLE 4 inverter Voltage vector substitution table under single tube open circuit fault
Figure BDA0003446276610000101
Figure BDA0003446276610000111
TABLE 5 inverter Voltage vector substitution representation under two-transistor open-circuit Fault
Figure BDA0003446276610000112
This embodiment uses T1For example, in a fault-tolerant operation state, the inverter can only output 3E, E, 0, -E, -2E and 3E 6 levels, and the number of output levels is changed from 7 types in a normal state to 6 types. V selected by current tracking control algorithm in non-fault state1、V4、V5、V6、V13、V14And V15Among 7 voltage vectors, V1、V4、V5And V13The device can not be influenced by the fault, can be continuously used and does not need to be replaced; v6、V14And V15Will be affected by the failure and will need to be replaced; wherein, V6And V15Respectively can adopt a voltage vector V7And V17Equivalent substitution is carried out, and the output levels of the inverters before and after substitution are the same; and V14Then no voltage vector with the same level value can be selected, and for simplifying the algorithm, vectors V with the same level direction and similar magnitude are selected13Or V17Replacement; namely, when h is less than or equal to 2h and 2h is less than or equal to 3h, the vector V is selected13(ii) a Or when 2h is less than or equal to 3h and delta i is more than 3h, selecting the vector V17。
When the inverter has double-tube open fault, 36 double-tube fault permutation and combination forms can occur in 9 groups of IGBTs. Through analysis, under the condition of 30 double-tube faults, the inverter can output at least 1 positive level, zero level and negative level, and fault-tolerant control can be performed through voltage vector replacement. Furthermore, when T is1And T4、T1And T8、T4And T9When a fault occurs at the same time, the output end of the inverter lacks a positive level; when T is2And T3、T2And T9、T3And T8And when a fault occurs, the negative level is lacked. In the 6 cases, fault-tolerant control cannot be realized through inverter topology reconstruction and voltage vector replacement.
Therefore, the effective voltage vector can be reasonably selected according to the current tracking error on the basis of the tables 4 and 5, and the actual output current of the inverter is controlled to rise and fall, so that the reference current is tracked, and the fault-tolerant control is realized.
In the embodiment, in order to verify the correctness and the effectiveness of the method, a system experiment platform is built for verification and analysis; the system parameters are as follows: 2 power supply voltages on the direct current side of the inverter are respectively 24V and 12V; the output end inductance is 5mH, the resistance is 5 omega, the reference current is a sine wave with the amplitude of 4A, and the hysteresis loop width h of each step is 0.1A. The model of an IGBT of the inverter power switching device is BSM50GB120DN 2; the power diode adopts a single-phase rectifier bridge MDQ 60-1600V; the driving circuit adopts a falling wood source integrated IGBT driving module DA962D 6; the system main control chip adopts 32-bit DSP TMS320F 28335; the inverter dead time is set to 4.27 mus; in the experiment, the model of the oscilloscope is DS1052E, and the power quality analyzer is HIOKI PW 3198;
fig. 10 is a graph of inverter output voltage and current waveforms in a non-fault state, and fig. 11 is a corresponding graph of current THD. As can be seen from fig. 10 and 11, when all the switching devices are normal, the voltage waveform and the current waveform output by the inverter both change according to the sine rule; the output voltage at this time is 7 levels, the output current can accurately track the reference value, and the current harmonic distortion rate is 1.48%.
The embodiment also analyzes the single-tube open-circuit fault and the double-tube open-circuit fault respectively; wherein, single tube open circuit fault analysis is as follows:
respectively converting T in inverter1～T9And the IGBT is disconnected one by one, so that the state of each IGBT when an open-circuit fault occurs is generated. Since there are many failure conditions, the present embodiment uses only T1A single tube failure is an example as shown in fig. 12 and 13. The waveforms of the corresponding fault-tolerant method in case of single-tube failure are shown in fig. 14 and 15.
As can be seen in fig. 12-13, when T is reached1When an open circuit fault occurs, the inverter output levels will lack 3E, 2E and 0 levels; while the 3 levels-E, -2E and-3E in the negative half-axis are unaffected. Therefore, the waveform of the output current obviously has irregular change in the positive half shaft part, and the negative half shaft waveform part is basically not influenced; the current distortion rate was as high as 52.5%.
From T in FIGS. 14-151The fault-tolerant operation waveform is known, after the redundant voltage vector is used for replacement, the output level number of the inverter is increased to six levels, the output current waveform is recovered to be normal, the sine degree is good, and the current harmonic distortion rate in the fault-tolerant operation state is 1.53 percent and is slightly higher than that in the non-fault state.
Can obtain T in the same way5In the case of fault tolerance, as shown in fig. 16-17, the output current harmonic distortion rate is 1.72%. Other single tube open faults are not repeated here.
Through the analysis, under the state of single-tube open-circuit fault, the fault-tolerant control method based on voltage vector substitution can ensure that the output current of the inverter tracks the reference current more accurately, and the total distortion rate of current harmonics is slightly improved compared with that before the fault. This is due to the fact that during voltage vector replacement, inverter output level errors cause an increase in current tracking errors.
The dual tube open circuit fault analysis is as follows:
the dual tube fault condition of this embodiment is only at T1And T2For example, when a fault occurs simultaneously, a fault waveform is shown in fig. 18. When T is1And T2When faults happen simultaneously, the number of output levels of the inverter is reduced to 2 from 7 before the faults occur; due to the loss of most output levels, the inverter cannot normally track the reference current, and the output voltage and the current also have obvious irregular changes.
The inverter output voltage, current and distortion rate after fault-tolerant control of the double-tube fault are shown in figures 19-20. As can be seen from the figure, after fault-tolerant control, the output current of the inverter is basically recovered to be normal, the sine degree is better, and the current harmonic distortion rate is 1.59%. Can obtain T in the same way4And T5The fault-tolerant operation condition when the double-tube fault occurs is shown in fig. 21-22, the output current sine degree is better at the moment, and the current harmonic distortion rate is 1.63%.
Through the analysis, under the double-tube open-circuit fault state, the fault-tolerant control method is utilized to ensure that the output current of the inverter can accurately track the reference current, and the current harmonic distortion rate is slightly improved compared with that before the fault.
In summary, when the inverter has a single-tube open circuit or a double-tube open circuit fault, the fault-tolerant control method can ensure that the inverter can accurately track the reference current, i.e. ensure that the system continues to operate stably.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit of the corresponding technical solutions and scope of the present invention as defined in the appended claims.

Claims (5)

1. A hysteresis loop SVPWM reconfigurable fault-tolerant control method of a single-phase voltage source multilevel inverter is characterized in that: the method comprises the following steps:
step 1, constructing a single-phase multi-level voltage source inverter;
step 2, controlling the tracking error of the inverter constructed in the step 1 in a hysteresis range;
step 3, when the voltage vector selected by the current tracking control algorithm in the non-fault state before the fault occurs is a non-fault vector, the voltage vector is the final output vector of the inverter; when the selected voltage vector is a fault vector, voltage vector substitution is required;
step 4, hysteresis SVPWM reconfigurable fault-tolerant control is carried out; reasonably selecting an effective voltage vector according to the current tracking error, and preferentially selecting a redundant voltage vector with coincident positions for equivalent substitution; if no redundant voltage vector with coincident position exists, other non-fault vectors with the closest position and action effect are selected to control the actual output current of the inverter to rise and fall, so that the reference current is tracked, and the fault-tolerant control is realized.
2. The single-phase voltage source multilevel inverter hysteresis SVPWM reconfigurable fault-tolerant control method of claim 1, characterized in that: the single-phase multi-level voltage source inverter in the step 1 consists of 2 independent direct current power supplies and 9 groups of power switching devices T1-T9Composition is carried out; wherein, 3 groups of switching devices T5、T8And T9A common single-phase bridge type uncontrollable rectification module is adopted, and an IGBT is arranged on the direct current side of a rectification bridge; the switching state and the voltage space vector of the inverter are shown in a table 1, the inverter has 17 switching states and voltage space vectors, and outputs 7 levels of 3E, 2E, E, 0, -E, -2E and 3E;
TABLE 1 inverter switching State and Voltage vector
Figure FDA0003446276600000011
Figure FDA0003446276600000021
Wherein u isABThe inverter outputs a phase voltage, and E is a dc power supply voltage.
3. The single-phase voltage source multi-level inverter hysteresis SVPWM reconfigurable fault-tolerant control method of claim 2, characterized in that: the specific method for selecting the inverter voltage vector to reduce the tracking error to the hysteresis range in the step 2 is as follows:
firstly, determining the current tracking error delta i-i of the inverter by using hysteresis loop comparison*-i, wherein i*Is the reference current, i is the actual current; then, the tracking error is reduced to be within a hysteresis range by selecting an inverter voltage vector;
setting the widths of the third-order hysteresis loops as h, 2h and 3h respectively; the voltage vector selection method under the non-fault state is shown in table 2; under the fault state, equivalently replacing the voltage vector selected by the current tracking control algorithm under the non-fault state, namely carrying out fault-tolerant control;
respectively selecting voltage space vector V under non-fault state1、V4、V5、V6、V13、V14And V15To generate 3E, 2E, E, 0, -E, -2E, -3E 7 levels; that is, only 1 inverter switching state is reserved for each level; at this time, the switching device T6And T7Only participate in the work during fault-tolerant control;
TABLE 2 hysteresis control method in non-failure state
Tracking error Vector uAB △i＞3h V15～V17 3E 2h＜△i≤3h V14 2E h＜△i≤2h V13 E -h≤△i≤h V6～V12 0 -2h≤△i＜-h V5 -E -3h≤△i＜-2h V4 -2E △i＜-3h V1～V3 -3E
When one or more IGBTs in the inverter have open-circuit faults, some voltage vectors are influenced by the faults and become fault vectors, as shown in Table 3;
TABLE 3 Effect of single tube open-circuit Fault on inverter
Figure FDA0003446276600000022
Figure FDA0003446276600000031
Wherein "√" means that the fault has no effect on the voltage vector; "x" indicates an effect, i.e., the voltage vector becomes a fault vector.
4. The single-phase voltage source multilevel inverter hysteresis SVPWM reconfigurable fault-tolerant control method of claim 3, characterized in that: step 3, when the selected voltage vector is a fault vector, the specific method for voltage vector replacement is as follows:
(1) replacing a voltage vector of the inverter under the condition of single-tube open circuit fault;
in the voltage vectors selected by the current tracking control algorithm in the non-fault state, the voltage vectors which are not affected by the fault are continuously used without replacement; if the voltage vector affected by the fault has the voltage vector with the same level value as the voltage vector, the voltage vector with the same level value is used for equivalent substitution, and the output levels of the inverters before and after substitution are the same; if no voltage vector with the same level value can be selected, selecting the vector with the same level direction and the size smaller than the set threshold value for substitution;
(2) replacing a voltage vector of the inverter under the condition of double-tube open circuit fault;
when the inverter has double-tube open-circuit fault, at least 1 positive level, zero level and negative level can be output, and fault-tolerant control is performed through voltage vector substitution; when the inverter has a double-tube open-circuit fault, if the output end lacks a positive level or a negative level, fault-tolerant control cannot be realized through inverter topology reconstruction and voltage vector replacement, and then step 4 is executed.
5. The single-phase voltage source multilevel inverter hysteresis SVPWM reconfigurable fault-tolerant control method of claim 4, characterized in that: the specific method of the step 4 comprises the following steps:
when the voltage vector selected by the current tracking control algorithm in the non-fault state before the fault occurs is a non-fault vector, the voltage vector is the final output vector of the inverter; when the selected voltage vector is a fault vector, voltage vector substitution is required; the voltage vector substitution method under the single-tube open circuit and double-tube open circuit faults of the inverter is shown in tables 4-5;
TABLE 4 inverter Voltage vector substitution table under single tube open circuit fault
Figure FDA0003446276600000041
TABLE 5 inverter Voltage vector substitution representation under two-transistor open-circuit Fault
Figure FDA0003446276600000042
Wherein, the single tube open circuit fault comprises 9 types, and the double tube open circuit fault comprises 36 types; "√" indicates that the fault has no effect on the voltage vector and does not need to be replaced; in table 5, the case of "none" is "when the inverter has a double-tube open-circuit fault, if the output terminal lacks a positive level or lacks a negative level, the fault-tolerant control cannot be realized through inverter topology reconstruction and voltage vector replacement.
CN202111657214.2A 2021-12-30 2021-12-30 Reconfigurable fault-tolerant control method for hysteresis SVPWM of single-phase voltage source multi-level inverter Active CN114301321B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202111657214.2A CN114301321B (en) 2021-12-30 2021-12-30 Reconfigurable fault-tolerant control method for hysteresis SVPWM of single-phase voltage source multi-level inverter

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202111657214.2A CN114301321B (en) 2021-12-30 2021-12-30 Reconfigurable fault-tolerant control method for hysteresis SVPWM of single-phase voltage source multi-level inverter

Publications (2)

Publication Number Publication Date
CN114301321A true CN114301321A (en) 2022-04-08
CN114301321B CN114301321B (en) 2024-01-19

Family

ID=80973922

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202111657214.2A Active CN114301321B (en) 2021-12-30 2021-12-30 Reconfigurable fault-tolerant control method for hysteresis SVPWM of single-phase voltage source multi-level inverter

Country Status (1)

Country Link
CN (1) CN114301321B (en)

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101494425A (en) * 2009-01-19 2009-07-29 上海海事大学 Three-phase mixing multi-level inverter circuit
CN102005957A (en) * 2010-11-04 2011-04-06 燕山大学 Single-power supply cascade multi-level converter
CN103378759A (en) * 2012-04-19 2013-10-30 马文忠 Method for controlling NPC three-level inverter fault redundancy
CN103532420A (en) * 2013-10-31 2014-01-22 哈尔滨工业大学 Dual-three-level online-topology switchable inverter
CN103560689A (en) * 2013-10-31 2014-02-05 辽宁工程技术大学 Method for achieving fault-tolerant control of medium-voltage cascading STATCOM through redundancy voltage vectors
CN106100405A (en) * 2016-06-30 2016-11-09 华东交通大学 A kind of level quinque switch H bridge multi-electrical level inverter
EP3193441A1 (en) * 2016-01-13 2017-07-19 GE Energy Power Conversion Technology Ltd Fault tolerant 3-level 3-phase npp converter and control method therefor
CN111262422A (en) * 2020-03-19 2020-06-09 中国科学院电工研究所 Three-level NPC inverter fault-tolerant control method based on carrier comparison
CN112615385A (en) * 2020-12-11 2021-04-06 武汉理工大学 Novel static var generator based on vector generator design
US11121643B1 (en) * 2020-11-12 2021-09-14 King Abdulaziz University Active neutral point clamped inverter with a plurality of boost levels
CN113708655A (en) * 2021-09-01 2021-11-26 同济大学 Fault-tolerant control method for inverter switching tube based on self-adaptive SVPWM

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101494425A (en) * 2009-01-19 2009-07-29 上海海事大学 Three-phase mixing multi-level inverter circuit
CN102005957A (en) * 2010-11-04 2011-04-06 燕山大学 Single-power supply cascade multi-level converter
CN103378759A (en) * 2012-04-19 2013-10-30 马文忠 Method for controlling NPC three-level inverter fault redundancy
CN103532420A (en) * 2013-10-31 2014-01-22 哈尔滨工业大学 Dual-three-level online-topology switchable inverter
CN103560689A (en) * 2013-10-31 2014-02-05 辽宁工程技术大学 Method for achieving fault-tolerant control of medium-voltage cascading STATCOM through redundancy voltage vectors
EP3193441A1 (en) * 2016-01-13 2017-07-19 GE Energy Power Conversion Technology Ltd Fault tolerant 3-level 3-phase npp converter and control method therefor
CN106100405A (en) * 2016-06-30 2016-11-09 华东交通大学 A kind of level quinque switch H bridge multi-electrical level inverter
CN111262422A (en) * 2020-03-19 2020-06-09 中国科学院电工研究所 Three-level NPC inverter fault-tolerant control method based on carrier comparison
US11121643B1 (en) * 2020-11-12 2021-09-14 King Abdulaziz University Active neutral point clamped inverter with a plurality of boost levels
CN112615385A (en) * 2020-12-11 2021-04-06 武汉理工大学 Novel static var generator based on vector generator design
CN113708655A (en) * 2021-09-01 2021-11-26 同济大学 Fault-tolerant control method for inverter switching tube based on self-adaptive SVPWM

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
XIONG LI；SERKAN DUSMEZ: "A New Active Fault-Tolerant SVPWM Strategy for Single-Phase Faults in Three-Phase Multilevel Converters", IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, vol. 62, no. 6, XP011580636, DOI: 10.1109/TIE.2014.2364555 *
马兰珍;向立文;潘春林;陶冶;: "新式七电平逆变器及其并网控制分析", 电力安全技术, no. 09 *

Also Published As

Publication number Publication date
CN114301321B (en) 2024-01-19

Similar Documents

Publication Publication Date Title
Neyshabouri et al. A new fault-tolerant strategy for a cascaded H-bridge based STATCOM
Arazm et al. ZPUC: A new configuration of single DC source for modular multilevel converter applications
Yan et al. A study on MMC model and its current control strategies
Fahad et al. Implementation and analysis of a 15-level inverter topology with reduced switch count
Wang et al. An efficient modulation strategy for cascaded photovoltaic systems suffering from module mismatch
Li et al. Controlled transition full-bridge hybrid multilevel converter with chain-links of full-bridge cells
Salehi et al. Predictive control of grid-connected modified-chb with reserve batteries in photovoltaic application under asymmetric operating condition
Lee et al. A hybrid binary-cascaded multilevel inverter with simple floating-capacitor-voltage control
Hatano et al. A configuration and control method of cascade H-bridge STATCOM
Naik et al. A new two-phase five-level converter for three-phase isolated grid-tied systems with inherent capacitor balancing and reduced component count
Xu A new multilevel AC/DC topology based H-bridge alternate arm converter
Xue et al. Seamless fault-tolerant control for cascaded H-bridge converters based battery energy storage system
Xia et al. A distributed voltage balancing method for modular multilevel converter
CN109038586B (en) Medium-voltage CS-APF fault-tolerant control method based on selective current limiting
Haghnazari et al. Fault tolerant operation strategy design for modular multilevel converters
Song et al. Open-circuit fault analysis and fault-tolerant control for 2/3-level DAB converters
Zhang et al. Study on fault tolerant control strategy for sub-modules of modular multilevel converter
CN114301321B (en) Reconfigurable fault-tolerant control method for hysteresis SVPWM of single-phase voltage source multi-level inverter
Majumdar et al. Optimum structure-based multi-level inverter with doubling circuit configuration
CN112701944B (en) Topology structure and control strategy of multi-level converter based on split power unit
CN110311543B (en) Topology reconstruction and power factor angle calculation method for cascade H-bridge converter during fault
Kankanala et al. Modeling and control of cascaded bridgeless multilevel rectifier under unbalanced load conditions
Wang et al. Extendable space-type switched-capacitor multilevel inverter with fault-tolerant capability
Yan et al. Enhanced Dynamic Voltage Balance Control of Modular Multilevel Matrix Converters with Switched Circulating Current Control
Sun et al. Research on voltage and switching balance control for cascaded power electronic transformer under hybrid PWM modulation

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