CN114553038B - Space type DC/AC converter and fault-tolerant operation method thereof - Google Patents

Space type DC/AC converter and fault-tolerant operation method thereof Download PDF

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Publication number
CN114553038B
CN114553038B CN202210183909.XA CN202210183909A CN114553038B CN 114553038 B CN114553038 B CN 114553038B CN 202210183909 A CN202210183909 A CN 202210183909A CN 114553038 B CN114553038 B CN 114553038B
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switch
module
tube
capacitor
converter
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CN114553038A (en
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王要强
张亨泰
赖锦木
陈天锦
王克文
梁军
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Zhengzhou University
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Zhengzhou University
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483—Converters with outputs that each can have more than two voltages levels
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Rectifiers (AREA)

Abstract

The invention provides a space type DC/AC converter and a fault-tolerant operation method thereof, wherein the space type DC/AC converter comprises a direct current power supply E, a basic switch capacitor module, N switch capacitor sub-modules, a half-bridge I and a half-bridge II; electrolytic capacitor C of ith switch capacitor sub-module i3 Electrolytic capacitor C with i-1 switch capacitor sub-module (i‑1)3 Through a switching tube S i6 And a switch tube S i7 And (5) cross-connecting. The space type DC/AC converter is controlled to work in 2N+5 modes through a driving signal, and 2N+5 levels are output: 0. (+) -E, + -2E, … …, + - (N+2) E; wherein N represents the number of switched capacitor sub-modules. The invention can be extended by adding a capacitor and a switching device, and the space-type DC/AC converter can bear open circuit faults by separating a charging loop and a discharging loop.

Description

Space type DC/AC converter and fault-tolerant operation method thereof
Technical Field
The invention relates to a converter, in particular to a space type DC/AC converter and a fault-tolerant operation method thereof.
Background
Multilevel converters have been widely used in renewable energy power generation systems (especially photovoltaic power generation systems), power distribution systems, electric vehicles, and the like. The main advantages of these systems include a stepped voltage that achieves lower total harmonic distortion, less electromagnetic interference, and a switching tube that is subject to lower voltage stress.
As with conventional multilevel converters, research into Neutral Point Clamped (NPC), flying Capacitor (FC), and cascaded H-bridge (CHB) multilevel converters has been perfected. However, neutral point clamped and flying capacitor multilevel converters require a large number of diodes or capacitors, and the implementation of capacitor voltage self-balancing or additional charging circuits adds to their complexity and cost. CHB multilevel converters use multiple isolated sources to boost the output level. In addition, the low voltage gain (ratio of maximum output voltage to input voltage) and single expansion limits the development of conventional multilevel converters. To solve these problems, a novel multi-level converter based on switched capacitor technology has been proposed and rapidly developed.
The capacitor of the switched capacitor multilevel converter (SCMLI) is charged in parallel with the DC power supply and discharged in series to obtain high voltage gain. In addition, SCMLI outputs the same level with fewer devices than conventional multi-level converters, and has advantages of capacitor voltage self-balancing and low voltage ripple.
Based on field experience, power devices such as Insulated Gate Bipolar Transistors (IGBTs) and metal-oxide semiconductor field effect transistors (MOSFETs) are prone to failure. Therefore, low reliability is one of the main problems of the multilevel converter due to the large number of switching transistors and capacitors.
Fault tolerant techniques are considered to be an effective way to improve the reliability of converters, and in recent years, fault tolerant operation of multilevel converters has received a lot of attention, mainly including two ways:
(1) The purpose of the redundant branch is to isolate the fault branch when the fault occurs and replace the fault branch by the redundant branch. This solution, while maintaining the continuity of the output level, increases the number of devices, the cost of the converter and the complexity of control;
(2) A control solution without additional devices is not achieved by directly changing the control strategy of the converter, which solution has the inherent drawback that the output level after failure is reduced, limiting its application.
In order to solve the above problems, an ideal technical solution is always sought.
Disclosure of Invention
The invention aims at overcoming the defects of the prior art, and provides a space type DC/AC converter and a fault-tolerant operation method thereof.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
the first aspect of the present invention provides a space-type DC/AC converter, which comprises a DC power supply E, a basic switched capacitor module, N switched capacitor sub-modules, a half-bridge I and a half-bridge II, wherein the basic switched capacitor module comprises a switching tube S 1 Switch tube S 2 Switch tube S 4 Switch tube S 5 Diode D 1 Diode D 2 Electrolytic capacitor C 1 And an electrolytic capacitor C 2 The half bridge I comprises a switching tube S 8 And a switch tube S 9 The half bridge II comprises a switching tube S 10 And a switch tube S 11 ；
When n=1, the switch capacitor submodule comprises a switch tube S 3 Switch tube S 6 Switch tube S 7 Diode D 3 And an electrolytic capacitor C 3 ；
Switching tube S of basic switch capacitor module 1 Respectively with the input end of the switch tube S 2 Input terminal of the switch capacitor sub-module, switch tube S of the switch capacitor sub-module 3 Is connected with the positive pole of the DC power supply E, the switch tube S 1 Respectively with the output end of the switch tube S 4 Is connected with the input end of the electrolytic capacitor C 1 Is connected with the anode of the switch tube S 2 Respectively with the output end of the switch tube S 5 Input terminal of the switch capacitor sub-module, switch tube S of the switch capacitor sub-module 6 And an electrolytic capacitor C 2 Is connected with the anode of the battery; the switch tube S 4 The output ends of the switch capacitor sub-modules are respectively connected with a switch tube S of the switch capacitor sub-module 7 The diode D 2 Is connected with the input end of the electrolytic capacitor C 2 Is connected with the cathode of the switch tube S 5 Respectively with the output end of the diode D 1 Is connected with the input end of the electrolytic capacitor C 1 Cathode of (2)Connecting;
switch tube S of switch capacitor sub-module 3 Respectively with the output end of the switch tube S 7 Is connected with the input end of the electrolytic capacitor C 3 Is connected with the anode of the switch tube S 6 Respectively with the output end of the diode D 3 And an electrolytic capacitor C 3 Is connected with the cathode of the battery;
the negative electrode of the direct current power supply E is respectively connected with a diode D of the basic switch capacitor module 1 Output of (D) and diode D 2 And diode D of said switched capacitor sub-module 3 Is connected with the output end of the power supply;
switching tube S of half bridge I 8 An electrolytic capacitor C of the basic switched capacitor module and the input terminal of the basic switched capacitor module 1 Is connected with the anode of the switch tube S 8 And the output end of the switch tube S 9 Is connected with the input end of the switch tube S 9 An output end of (C) and an electrolytic capacitor of the basic switch capacitor module 1 Is connected with the cathode of the battery; switching tube S of half-bridge II 10 An electrolytic capacitor C of the switch capacitor sub-module and the input terminal of the switch capacitor sub-module 3 Is connected with the anode of the switch tube S 10 And the output end of the switch tube S 11 Is connected with the input end of the switch tube S 11 An output terminal of the switch capacitor sub-module and an electrolytic capacitor C of the switch capacitor sub-module 3 Is connected with the cathode of the battery;
when N is more than or equal to 2, the ith switch capacitor submodule comprises an electrolytic capacitor C i3 Diode D i3 Switch tube S i3 Switch tube S i6 And a switch tube S i7 ，2≤i≤N；
Electrolytic capacitor C of ith switch capacitor sub-module i3 Electrolytic capacitor C with i-1 switch capacitor sub-module (i-1)3 Through a switching tube S i6 And a switch tube S i7 Cross-connect; electrolytic capacitor C of ith switch capacitor sub-module i3 The anode of (C) is also connected with a switch tube S i3 Is connected with the output end of the switch tube S i3 The input end of the base switch capacitor module is respectively connected with the positive electrode of the direct current power supply E and the switch tube S of the base switch capacitor module 1 Is input to the (d)Switch tube S 2 Input terminal of (d) and switching tube S (i-1)3 Is connected with the input end of the power supply; electrolytic capacitor C of ith switch capacitor sub-module i3 And also with diode D i3 Is connected with the input end of diode D i3 Respectively connected with the negative electrode and the diode D of the direct current power supply E (i-1)3 Diode D of said basic switched capacitor module 1 Output of (D) and diode D 2 Is connected with the output end of the power supply;
electrolytic capacitor C of Nth switch capacitor sub-module N3 Is connected with the switching tube S of the half bridge II 10 Is connected with the input end of the electrolytic capacitor C N3 And the switching tube S of the half bridge II 11 Is connected with the output end of the power supply.
A second aspect of the present invention provides a modulation method for a space-type DC/AC converter, which controls the space-type DC/AC converter according to claim 1 or 2 to operate in 2n+5 modes by a driving signal, and outputs 2n+5 levels: 0. (+) -E, + -2E, … …, + - (N+2) E; wherein N represents the number of switched capacitor sub-modules.
A third aspect of the invention provides a fault tolerant method of operation of a space-type DC/AC converter,
when the space type DC/AC converter has no open circuit fault, the space type DC/AC converter comprising a switch capacitor sub-module is controlled to work in seven modes by a driving signal, and seven levels are output: 0. + -E, + -2E, and + -3E;
switching tube S of basic switch capacitor module 1 When in fault, the space type DC/AC converter comprising a switch capacitor sub-module is controlled to work in five modes by a driving signal, and five levels are output: 0. + -E and + -2E;
switching tube S of basic switch capacitor module 2 Or switch tube S 4 Or switch tube S 5 When in fault, the space type DC/AC converter comprising a switch capacitor sub-module is controlled to work in three modes by a driving signal, and three levels are output: 0 and ± E;
switching tube S of the switch capacitor sub-module 3 By driving the letter in case of failureThe space type DC/AC converter comprising a switch capacitor sub-module is controlled to work in five modes and outputs five levels: 0. + -E and + -2E;
switching tube S of the switch capacitor sub-module 6 Or switch tube S 7 When in fault, the space type DC/AC converter comprising a switch capacitor sub-module is controlled to work in three modes by a driving signal, and three levels are output: 0 and ± E;
Switching tube S of half bridge I 8 Or switch tube S 9 When in fault, the space type DC/AC converter comprising a switch capacitor sub-module is controlled to work in five modes by a driving signal, and five levels are output: 0. + -E and + -2E;
switching tube S in the half bridge II 10 Or switch tube S 11 When in fault, the space type DC/AC converter comprising a switch capacitor sub-module is controlled to work in five modes by a driving signal, and five levels are output: 0. + -E and + -2E.
A fourth aspect of the present invention provides a space-type DC/AC conversion system comprising a controller and a converter, the converter being the space-type DC/AC converter described above.
The fifth aspect of the present invention provides a fault tolerant system of a space-type DC/AC converter, comprising a controller and a space-type DC/AC converter, wherein the controller executes the steps of the fault tolerant operation method of the space-type DC/AC converter when controlling the switching tube in the space-type DC/AC converter to act.
The beneficial effects of the invention are as follows:
1) The invention provides a space type DC/AC converter, which comprises a switch capacitor sub-module, wherein the space type DC/AC converter uses 1 direct current power supply, 3 capacitors and 11 switch devices to realize 3 times of voltage gain and 7 level alternating voltage output; by separating the charging loop and the discharging loop, the topological structure can realize fault-tolerant operation and improve the reliability of the converter;
Two half-bridges are used for replacing an H bridge to convert the polarity of an output level and reduce the voltage stress of a switching tube of the switching tube; wherein, switch tube S 1 And S is equal to 3 Is at maximum voltage stress of2E, the maximum voltage stress of the rest switching tubes is E;
2) The space type DC/AC converter only uses one direct current power supply, and the output level is improved by adding the switch capacitor sub-module, so that the structure of the converter can be simplified to the greatest extent; each switch capacitor sub-module comprises three switch tubes, a diode and an electrolytic capacitor, and in the modularized expansion structure, each switch capacitor sub-module is added, so that the space type DC/AC converter is added with 2 output levels;
3) The space type DC/AC converter has the advantages of low voltage ripple, and at least one capacitor is charged at any level;
4) The capacitor is independently charged by the direct current power supply, so that the fault capacitor in the space-type DC/AC converter can be isolated by changing a control strategy;
5) In the switching tube S 1 Or diode D 1 When open circuit fault occurs, the electrolytic capacitor C is controlled by changing the control strategy 1 Isolated from its discharge circuit, switch tube S 4 And S is 8 S and S 5 And S is 9 Simultaneously open or close, switch tube S 8 And S is 9 Alternately conducting. At this time, the space-type DC/AC converter including one switched capacitor sub-module operates as a five-level converter;
at the on-off state S 2 Or diode D 2 When open circuit fault occurs, switch tube S 4 And S is 7 Switch tube S 5 And S is 6 Simultaneously on or off, capacitor C 1 And C 3 The series discharge is not possible. At this time, the space-type DC/AC converter including one switched capacitor sub-module operates as a three-level converter;
in the switching tube S 3 Or diode D 3 When an open circuit fault occurs, the space type DC/AC converter comprising a switch capacitor sub-module operates as a five-level converter;
due to the switching tube S 4 And S is 5 、S 6 And S is 7 Operating in a complementary state, when one of the two switching tubes operating in the complementary state is openThe other switching tube keeps a conducting state when the circuit fails; in the switching tube S 4 、S 5 、S 6 Or S 7 When any one of the switching tubes has an open-circuit fault, the space type DC/AC converter comprising one switch capacitor sub-module operates as a three-level converter;
due to the switching tube S 8 And S is 9 、S 10 And S is 11 When one of the two switching tubes breaks down, the other switching tube keeps on; in the switching tube S 8 、S 9 、S 10 Or S 11 When any one of the switching tubes has an open-circuit fault, the space type DC/AC converter comprising one switch capacitor sub-module operates as a five-level converter;
6) The voltage balance, the boosting capability and the capability of carrying inductive load of the capacitor can be kept in the running state before and after the fault; in the operation state after the fault, the voltage stress of the switching device and the voltage ripple of the capacitor are reduced or kept unchanged;
7) If a fast fuse or a circuit breaker is used to isolate the short-circuit switching tube, the space-type DC/AC converter can be used for short-circuit fault tolerance;
8) The fault-tolerant operation method is particularly suitable for the expansion converter with high output level, and is particularly suitable for the expandable converter, wherein the fault-tolerant operation method reduces four output levels at most.
Drawings
FIG. 1 is a topology of a space-based DC/AC converter of the present invention;
FIGS. 2 (a) to 2 (g) are schematic circuit diagrams of seven modes of operation of a space-type DC/AC converter (in normal operation) of the present invention comprising a switched capacitor sub-module;
FIG. 3 is a schematic diagram of carrier and modulation waveforms of a space-type DC/AC converter including a switched capacitor sub-module according to the present invention;
FIG. 4 is a schematic diagram of the original PWM pulse waveform of a space-type DC/AC converter of the present invention including a switched capacitor sub-module;
FIG. 5 is a waveform of control signals for each switching tube of a space-type DC/AC converter including a switched capacitor sub-module of the present invention;
FIG. 6 is a schematic diagram of a target output waveform of a space-type DC/AC converter of the present invention including a switched capacitor sub-module;
FIG. 7 is a schematic diagram of output voltage waveforms and output current waveforms for a resistive inductive load of a space-type DC/AC converter including a switched capacitor sub-module according to the present invention;
FIGS. 8 (I) to 8 (V) illustrate a switching tube S of a space-type DC/AC converter including a switched capacitor sub-module according to the present invention 1 A circuit schematic diagram of five working modes during fault;
FIG. 9 is a switching tube S 1 An output waveform diagram of fault-tolerant operation of a space-type DC/AC converter comprising a switch capacitor sub-module after a fault occurs;
FIGS. 10 (i) to 10 (v) illustrate a switching tube S of a space-type DC/AC converter including a switched capacitor sub-module according to the present invention 8 A circuit schematic diagram of five working modes during fault;
fig. 11 is a topology diagram of an extended space-type DC/AC converter of the present invention.
Detailed Description
The technical scheme of the invention is further described in detail through the following specific embodiments.
Example 1
Fig. 1 shows a schematic topology of a space-type DC/AC converter, which includes a DC power supply E, a basic switched capacitor module including a switching tube S, N switched capacitor sub-modules, a half-bridge i and a half-bridge ii 1 Switch tube S 2 Switch tube S 4 Switch tube S 5 Diode D 1 Diode D 2 Electrolytic capacitor C 1 And an electrolytic capacitor C 2 The half bridge I comprises a switching tube S 8 And a switch tube S 9 The half bridge II comprises a switching tube S 10 And a switch tube S 11 ；
When n=1The switch capacitor submodule comprises a switch tube S 3 Switch tube S 6 Switch tube S 7 Diode D 3 And an electrolytic capacitor C 3 ；
Switching tube S of basic switch capacitor module 1 Respectively with the input end of the switch tube S 2 Input terminal of the switch capacitor sub-module, switch tube S of the switch capacitor sub-module 3 Is connected with the positive pole of the DC power supply E, the switch tube S 1 Respectively with the output end of the switch tube S 4 Is connected with the input end of the electrolytic capacitor C 1 Is connected with the anode of the switch tube S 2 Respectively with the output end of the switch tube S 5 Input terminal of the switch capacitor sub-module, switch tube S of the switch capacitor sub-module 6 And an electrolytic capacitor C 2 Is connected with the anode of the battery; the switch tube S 4 The output ends of the switch capacitor sub-modules are respectively connected with a switch tube S of the switch capacitor sub-module 7 The diode D 2 Is connected with the input end of the electrolytic capacitor C 2 Is connected with the cathode of the switch tube S 5 Respectively with the output end of the diode D 1 Is connected with the input end of the electrolytic capacitor C 1 Is connected with the cathode of the battery;
switch tube S of switch capacitor sub-module 3 Respectively with the output end of the switch tube S 7 Is connected with the input end of the electrolytic capacitor C 3 Is connected with the anode of the switch tube S 6 Respectively with the output end of the diode D 3 And an electrolytic capacitor C 3 Is connected with the cathode of the battery;
the negative electrode of the direct current power supply E is respectively connected with a diode D of the basic switch capacitor module 1 Output of (D) and diode D 2 And diode D of said switched capacitor sub-module 3 Is connected with the output end of the power supply;
switching tube S of half bridge I 8 An electrolytic capacitor C of the basic switched capacitor module and the input terminal of the basic switched capacitor module 1 Is connected with the anode of the switch tube S 8 And the output end of the switch tube S 9 Is connected with the input end of the switch tube S 9 And the output end of the basic switch capacitor module De-capacitance C 1 Is connected with the cathode of the battery; switching tube S of half-bridge II 10 An electrolytic capacitor C of the switch capacitor sub-module and the input terminal of the switch capacitor sub-module 3 Is connected with the anode of the switch tube S 10 And the output end of the switch tube S 11 Is connected with the input end of the switch tube S 11 An output terminal of the switch capacitor sub-module and an electrolytic capacitor C of the switch capacitor sub-module 3 Is connected with the cathode of the battery;
when N is more than or equal to 2, the ith switch capacitor submodule comprises an electrolytic capacitor C i3 Diode D i3 Switch tube S i3 Switch tube S i6 And a switch tube S i7 ，2≤i≤N；
Electrolytic capacitor C of ith switch capacitor sub-module i3 Electrolytic capacitor C with i-1 switch capacitor sub-module (i-1)3 Through a switching tube S i6 And a switch tube S i7 Cross-connect; electrolytic capacitor C of ith switch capacitor sub-module i3 The anode of (C) is also connected with a switch tube S i3 Is connected with the output end of the switch tube S i3 The input end of the base switch capacitor module is respectively connected with the positive electrode of the direct current power supply E and the switch tube S of the base switch capacitor module 1 Is connected with the input end of the switch tube S 2 Input terminal of (d) and switching tube S (i-1)3 Is connected with the input end of the power supply; electrolytic capacitor C of ith switch capacitor sub-module i3 And also with diode D i3 Is connected with the input end of diode D i3 Respectively connected with the negative electrode and the diode D of the direct current power supply E (i-1)3 Diode D of said basic switched capacitor module 1 Output of (D) and diode D 2 Is connected with the output end of the power supply;
electrolytic capacitor C of Nth switch capacitor sub-module N3 Is connected with the switching tube S of the half bridge II 10 Is connected with the input end of the electrolytic capacitor C N3 And the switching tube S of the half bridge II 11 Is connected with the output end of the power supply.
Wherein, the electrolytic capacitor C of the ith switch capacitor sub-module i3 Electrolytic capacitor C with i-1 switch capacitor sub-module (i-1)3 Through a switching tube S i6 And a switch tube S i7 The cross-connect is performed with the two-way connection,refers to: switch tube S i6 Respectively with the input end of the switch tube S (i-1)7 Input terminal of (2) switching tube S (i-1)3 Output terminal of (C) and electrolytic capacitor C (i-1)3 Is connected with the anode of the battery; switch tube S i6 Respectively with diode D i3 And an electrolytic capacitor C i3 Is connected with the cathode of the battery; switch tube S i7 Respectively with the input end of the switch tube S i3 Output terminal of (C) and electrolytic capacitor C i3 Is connected with the anode of the battery; switch tube S i7 Respectively with diode D (i-1)3 Input terminal of (2) switching tube S (i-1)6 Output terminal of (C) and electrolytic capacitor C (i-1)3 Is connected to the cathode of the battery.
It will be appreciated that the electrolytic capacitance C of the fundamental switched capacitor module of the space-type DC/AC converter 2 Electrolytic capacitor C with first switch capacitor sub-module 3 Between through a switch tube S 6 And a switch tube S 7 And (5) cross-connecting.
Specifically, the switching tube S of the basic switched capacitor module 4 And a switch tube S 5 Switch tube S of switch capacitor sub-module i6 And a switch tube S i7 Switching tube S of half bridge I and half bridge II 8 Switch tube S 9 Switch tube S 10 Switch tube S 11 Switching tube S of the basic switched capacitor module is a switching tube comprising a reverse diode 1 And a switch tube S 2 Switching tube S of the switched capacitor sub-module i3 Is a switching tube that does not include a reverse diode. It will be appreciated that the space-type DC/AC converter uses MOSFETs or IGBTs with anti-parallel diodes, providing a channel for feeding back no functional quantity from the AC output side to the DC input side; thus, the space-type DC/AC converter has the capability of carrying inductive loads.
It should be noted that, the space-type DC/AC converter can be expanded by increasing the number of the switch capacitor sub-modules, the DC power supply E charges all the switch capacitor sub-modules respectively, and each switch capacitor sub-module is discharged in series to increase the output level. In the modularized expansion structure, each time a switch capacitor sub-module is added, 2 output levels of the space type DC/AC converter are increased; the expansion mode not only can keep the advantages of the cascade expansion mode, but also only needs one direct current power supply.
It can be understood that each switch capacitor sub-module of the space type DC/AC converter includes three switch tubes, a diode and an electrolytic capacitor, and two adjacent switch capacitor sub-modules are set as a front stage switch capacitor sub-module and a rear stage switch capacitor sub-module according to the positional relationship between the switch capacitor sub-modules and the basic switch capacitor module;
the electrolytic capacitor of the post-stage switch capacitor sub-module is cross-connected with the electrolytic capacitor of the pre-stage switch capacitor sub-module through two switching tubes of the post-stage switch capacitor sub-module, the anode of the electrolytic capacitor of the post-stage switch capacitor sub-module is also connected with the output end of the other switching tube of the post-stage switch capacitor sub-module, and the input end of the other switching tube of the post-stage switch capacitor sub-module is respectively connected with the anode of the direct current power supply E and the switching tube S of the basic switch capacitor module 1 Is connected with the input end of the switch tube S 2 The input end of one of the switching tubes of the front-stage switching capacitor sub-module is connected; the cathode of the electrolytic capacitor of the rear-stage switch capacitor sub-module is also connected with the input end of the diode of the rear-stage switch capacitor sub-module, and the output end of the diode of the rear-stage switch capacitor sub-module is respectively connected with the cathode of the direct current power supply E, the output end of the diode of the front-stage switch capacitor sub-module and the diode D of the basic switch capacitor module 1 Output of (D) and diode D 2 Is connected with the output end of the power supply.
It should be noted that, the charging loop and the discharging loop in the space type DC/AC converter are separated, and the space type DC/AC converter has fault tolerance and expansibility; two "half-bridges" are used instead of an H-bridge to switch the polarity of the output level and reduce the voltage stress of its switching transistors.
Example 2
On the basis of the space-type DC/AC converter in embodiment 1, this embodiment provides a specific implementation manner of a modulation method of the space-type DC/AC converter:
the space-type DC/AC converter in embodiment 1 is controlled to operate in 2n+5 modes by the driving signal, and 2n+5 levels are output: 0. (+) -E, + -2E, … …, + - (N+2) E; wherein N represents the number of switched capacitor sub-modules.
As shown in fig. 2 (a) to 2 (g), when the space type DC/AC converter includes a switched capacitor sub-module, the space type DC/AC converter is controlled to operate in seven modes by a driving signal, and outputs seven levels: 0. + -E, + -2E, and + -3E; the space type DC/AC converter is controlled by a switching tube S 4 To a switching tube S 7 Realizes the series connection of electrolytic capacitors by controlling the on-off state of the switching tube S 1 To a switching tube S 3 Charging electrolytic capacitor in on state, switching tube S 8 And S is 9 S and S 10 And S is 11 Alternately conducting to produce a negative level.
Fig. 2 (a) to 2 (g) show working schematic diagrams of space type DC/AC converters comprising a switched capacitor sub-module in different modes, and symbols "+" and "-" represent positive and negative poles of an access load, and output voltage of the space type DC/AC converter is denoted by U. In the absence of an open circuit fault, a space-type DC/AC converter including a switched capacitor sub-module is configured to operate in seven modes, including:
operating state a: switch tube S 1 Switch tube S 5 Switch tube S 7 Switch tube S 8 And a switch tube S 11 On, the rest of the switch tubes are turned off, and the diode D 1 Conducting, wherein the rest diodes are in an idle state, and the output voltage U is 3E;
as shown in FIG. 2 (a), a switching tube S 1 DC power supply E and diode D 1 Forms a charging loop and a switch tube S 1 The conduction, direct current power supply E is an electrolytic capacitor C 1 Charging; switch tube S 8 Electrolytic capacitor C 1 Switch tube S 5 Electrolytic capacitor C 2 Switch tube S 7 Electrolytic capacitor C 3 And a switch tube S 11 Form a discharge loop and a switch tube S 5 And S is 7 Conduction and capacitance C 1 、C 2 And C 3 Discharging in series;
operating state b: switch tube S 1 Switch tube S 5 Switch tube S 7 Switch tube S 8 And a switch tube S 10 On, the rest of the switch tubes are turned off, and the diode D 1 Conducting, wherein the rest diodes are in an idle state, and the output voltage U is 2E;
as shown in FIG. 2 (b), a switching tube S 1 DC power supply E and diode D 1 Forms a charging loop and a switch tube S 1 The direct current power supply E is a capacitor C 1 Charging; switch tube S 8 Electrolytic capacitor C 1 Switch tube S 5 Electrolytic capacitor C 2 Switch tube S 7 And a switch tube S 10 Form a discharge loop and a switch tube S 5 And S is 7 Conduction and capacitance C 1 、C 2 Discharging in series;
working state c: switch tube S 2 Switch tube S 4 Switch tube S 7 Switch tube S 8 And a switch tube S 11 On, the rest of the switch tubes are turned off, and the diode D 2 Conducting, wherein the rest diodes are in an idle state, and the output voltage U is E;
as shown in FIG. 2 (c), a switching tube S 2 DC power supply E and diode D 2 And an electrolytic capacitor C 2 Forms a charging loop and a switch tube S 2 The direct current power supply E is a capacitor C 2 Charging; switch tube S 8 Switch tube S 4 Switch tube S 7 Electrolytic capacitor C 3 And a switch tube S 11 Form a discharge loop and a switch tube S 4 And S is 7 Conduction and capacitance C 3 Discharging;
operating state d: switch tube S 1 Switch tube S 3 Switch tube S 5 Switch tube S 6 Switch tube S 9 And a switch tube S 11 On, the rest of the switch tubes are turned off, and the diode D 1 And diode D 3 Conducting, wherein the rest diodes are in an idle state, and the output voltage U is 0;
as shown in FIG. 2 (d), an electrolytic capacitor C 1 Switch tube S 1 DC power supply E and switch tube S 3 Electrolytic capacitor C 3 Diode D 3 And diode D 1 Forms a charging loop and a switch tube S 1 And S is 3 The direct current power supply E is a capacitor C 1 、C 3 Charging; switch tube S 9 Switch tube S 5 Switch tube S 6 And a switch tube S 11 Forming a discharge loop;
operating state e: switch tube S 1 Switch tube S 3 Switch tube S 5 Switch tube S 6 Switch tube S 9 And a switch tube S 10 On, the rest of the switch tubes are turned off, and the diode D 1 And diode D 3 Conducting, wherein the rest diodes are in an idle state, and the output voltage U is-E;
as shown in FIG. 2 (e), an electrolytic capacitor C 1 Switch tube S 1 DC power supply E and switch tube S 3 Diode D 3 And diode D 1 Forms a charging loop and a switch tube S 1 And S is 3 The direct current power supply E is a capacitor C 1 、C 3 Charging; switch tube S 9 Switch tube S 5 Switch tube S 6 Electrolytic capacitor C 3 And a switch tube S 10 Form a discharge loop and a switch tube S 5 And S is 6 Conduction and capacitance C 3 Discharging;
working state f: switch tube S 3 Switch tube S 4 Switch tube S 6 Switch tube S 8 And a switch tube S 10 On, the rest of the switch tubes are turned off, and the diode D 3 Conducting, wherein the rest diodes are in an idle state, and the output voltage U is-2E;
as shown in FIG. 2 (f), a switching tube S 3 DC power supply E and diode D 3 Forms a charging loop and a switch tube S 3 The direct current power supply E is a capacitor C 3 Charging; switch tube S 8 Switch tube S 4 Electrolytic capacitor C 2 Switch tube S 6 Electrolytic capacitor C 3 And a switch tube S 10 Form a discharge loop and a switch tube S 4 And S is 6 Conduction and capacitance C 2 、C 3 Discharging in series;
working state g: switch tube S 3 Switch tube S 4 Switch tube S 6 Switch tube S 9 And a switch tube S 10 On, the rest of the switch tubes are turned off, and the diode D 3 Conducting, wherein the rest diodes are in an idle state, and the output voltage U is-3E;
as shown in FIG. 2 (g), a switching tube S 3 DC power supply E and diode D 3 Forms a charging loop and a switch tube S 3 The direct current power supply E is a capacitor C 3 Charging; switch tube S 9 Electrolytic capacitor C 1 Switch tube S 4 Electrolytic capacitor C 2 Switch tube S 6 Electrolytic capacitor C 3 And a switch tube S 10 Form a discharge loop and a switch tube S 4 And S is 6 Conduction and capacitance C 1 Capacitance C 2 Capacitance C 3 And (5) discharging in series.
It should be noted that when each switching tube of the space-type DC/AC converter including a switch capacitor sub-module works normally, a DC power supply can be used to realize seven-level step voltage output (+/-3E, ±2E, ±e, 0) and 3 times voltage gain; the maximum voltage stress of the switching tube is equal to 2E; wherein the switching tube S 1 And S is equal to 3 The maximum voltage stress of the rest of the switching transistors is 2E, and the maximum voltage stress of the rest of the switching transistors is E.
Further, when n=1, as shown in fig. 3, by comparing the sinusoidal modulation wave U ref With six triangular carriers u a1 To u a6 Obtaining a logic signal u 1 To u 6 Will logic signal u 1 To u 6 After logic combination, the driving signals of the switching tubes are output and obtained, and the driving signal expression of each switching tube is as follows:
when N is more than or equal to 2, the modulation method of the space type DC/AC converter is the same as the principle when N=1; by comparing sinusoidal modulation waves U ref And n+2 triangular carriers u a1 To u a（N+2） Obtaining logic signalsu 1 To u N+2 Will logic signal u 1 To u N+2 And after logic combination, outputting and obtaining driving signals of the switching tubes.
It will be appreciated that this embodiment proposes a modulation strategy based on the described space-type DC/AC converter comprising a switched capacitor sub-module, the modulation principle being shown in fig. 3 to 6. The strategy adopts a carrier wave lamination pulse width modulation technology, 6 paths of triangular carriers with the same amplitude and the same frequency are sequentially laminated, compared with 1 path of sine modulation waves, and then the obtained 6 paths of original pulse waveforms are logically combined to obtain a gate pulse signal for driving a switching tube to be switched on and off. The number of triangular carrier signals is determined based on the number of output levels (other than 0), and the switching tube state is predetermined according to the operation state of the space-type DC/AC converter, wherein redundant switch combination is considered; the on-off state of the switching tube in one cycle is analyzed and compared with the pulse shown in fig. 4.
The switching tube S 4 And a switch tube S 5 Working states are complementary, and switch tube S 6 And a switch tube S 7 Operating in a complementary state, switching tube S 8 And a switch tube S 9 Operating in a complementary state, switching tube S 10 And a switch tube S 11 Operate in a complementary state, thus reducing the control complexity of the space-type DC/AC converter.
In this embodiment, the space-type DC/AC converter including a switched capacitor sub-module is verified through experiments according to the modulation scheme, and fig. 7 shows the output voltage V when the converter is loaded with a resistive inductor o And load current I o Is a waveform diagram of (a). According to the waveform diagram, under the condition of a resistive load (R-L), the space type DC/AC converter can output a standard 7-level step voltage waveform when stably operating, and the output voltage reaches 3 times of boosting gain; its load current waveform appears as a smooth sinusoidal curve and lags behind the output voltage waveform. It has been found that the space-type DC/AC converter has the ability to provide an inductive load and the ability to self-balance the capacitive voltage.
Can be used forIt is understood that when N is greater than or equal to 2, the first switched capacitor sub-module includes a switch tube S 3 Switch tube S 6 Switch tube S 7 Diode D 3 And an electrolytic capacitor C 3 The ith switch capacitor submodule comprises an electrolytic capacitor C i3 Diode D i3 Switch tube S i3 Switch tube S i6 And a switch tube S i7 。
In a specific embodiment, the space DC/AC converter includes two switched capacitor submodules to form a nine-level space converter, and the topology structure is shown in fig. 11, and outputs nine levels: 0. + -E, + -2E, + -3E and + -4E; the first-stage switch capacitor sub-module comprises a switch tube S 3 Switch tube S 6 Switch tube S 7 Diode D 3 And an electrolytic capacitor C 3 The method comprises the steps of carrying out a first treatment on the surface of the The added switch capacitor sub-module is a second stage switch capacitor sub-module which comprises a switch tube S 23 Switch tube S 26 Switch tube S 27 Diode D 23 And an electrolytic capacitor C 23 ；
It will be appreciated that the nine-level space-type converter operates in a similar manner to the seven-level converter described above (space-type DC/AC converter comprising a switched capacitor sub-module); capacitor C 1 And C 3 Charging by DC power supply at output levels E and 2E, capacitor C 2 And C 23 Charging occurs at output levels 0 and-E.
On the basis of the space-type DC/AC converter in embodiment 1, this embodiment also provides a space-type DC/AC conversion system, which includes a controller and a converter, where the converter is the space-type DC/AC converter, and the controller executes the steps of the modulation method of the space-type DC/AC converter when controlling the switching tube in the space-type DC/AC converter to operate.
Example 3
On the basis of the embodiment 1, the embodiment provides a specific implementation mode of a fault-tolerant operation method of a space type DC/AC converter comprising a switch capacitor sub-module; it should be noted that, because the probability of simultaneous occurrence of faults of a plurality of switching tubes is small, the fault-tolerant operation method of the space type DC/AC converter is a modulation method after an open circuit fault occurs in a single switching tube or a single diode.
Specifically, when the space type DC/AC converter has no open circuit fault, the space type DC/AC converter including a switch capacitor sub-module is controlled to operate in seven modes by a driving signal, and seven levels are output: 0. + -E, + -2E, and + -3E;
switching tube S of basic switch capacitor module 1 When in fault, the space type DC/AC converter comprising a switch capacitor sub-module is controlled to work in five modes by a driving signal, and five levels are output: 0. + -E and + -2E;
switching tube S of basic switch capacitor module 2 Or switch tube S 4 Or switch tube S 5 When in fault, the space type DC/AC converter comprising a switch capacitor sub-module is controlled to work in three modes by a driving signal, and three levels are output: 0 and ± E;
Switching tube S of the switch capacitor sub-module 3 When in fault, the space type DC/AC converter comprising a switch capacitor sub-module is controlled to work in five modes by a driving signal, and five levels are output: 0. + -E and + -2E;
switching tube S of the switch capacitor sub-module 6 Or switch tube S 7 When in fault, the space type DC/AC converter comprising a switch capacitor sub-module is controlled to work in three modes by a driving signal, and three levels are output: 0 and ± E;
switching tube S of half bridge I 8 Or switch tube S 9 When in fault, the space type DC/AC converter comprising a switch capacitor sub-module is controlled to work in five modes by a driving signal, and five levels are output: 0. + -E and + -2E;
switching tube S in the half bridge II 10 Or switch tube S 11 When in fault, the space type DC/AC converter comprising a switch capacitor sub-module is controlled to work in five modes by a driving signal, and five levels are output: 0. + -E and + -2E.
Further, a diode D of the basic switch capacitor module 1 In the event of a fault, the space-type DC/AC converter comprising one switched capacitor sub-module is configured into five modes and outputs five levels: 0. + -E and + -2E;
diode D in the basic switched capacitor module 2 In the event of a fault, the space-type DC/AC converter comprising one switched capacitor sub-module is configured into three modes, and outputs three levels: 0 and ± E;
diode D in the switched capacitor sub-module 3 In the event of a fault, the space-type DC/AC converter comprising one switched capacitor sub-module is configured into five modes and outputs five levels: 0. + -E and + -2E.
If the switching tube S 1 、S 2 Or S 3 Diode D 1 、D 2 Or D 3 If an open circuit fault occurs, the corresponding electrolytic capacitor cannot be charged.
Specifically, in the switching tube S 1 Or diode D 1 When open circuit fault occurs, the electrolytic capacitor C is controlled by changing the control strategy 1 Isolated from its discharge circuit, switch tube S 4 And S is 8 S and S 5 And S is 9 Simultaneously open or close, switch tube S 8 And S is 9 Alternately conducting. At this time, the space-type DC/AC converter operates as a five-level converter;
at the on-off state S 2 Or diode D 2 When open circuit fault occurs, switch tube S 4 And S is 7 Switch tube S 5 And S is 6 Simultaneously on or off, capacitor C 1 And C 3 The series discharge is not possible. At this time, the space-type DC/AC converter operates as a three-level converter;
in the switching tube S 3 Or diode D 3 When an open circuit fault occurs, the space type DC/AC converter operates as a five-level converter;
Due to the switching tube S 4 And S is 5 、S 6 And S is 7 When any one of the two switching tubes works in the complementary state and has an open-circuit fault, the other switching tube is kept in a conducting state; in the switch tubeS 4 、S 5 、S 6 Or S 7 When any one of the switching tubes has an open-circuit fault, the space type DC/AC converter operates as a three-level converter;
due to the switching tube S 8 And S is 9 、S 10 And S is 11 When any one of the two switching tubes works in the complementary state and has an open-circuit fault, the other switching tube is kept in a conducting state; in the switching tube S 8 、S 9 、S 10 Or S 11 When any one of the switching tubes has an open-circuit fault, the space type DC/AC converter operates as a five-level converter.
On the basis of the fault-tolerant operation method of the space-type DC/AC converter, the embodiment provides a specific implementation mode of a fault-tolerant system of the space-type DC/AC converter, the fault-tolerant system comprises a controller and the space-type DC/AC converter, and the controller executes the steps of the fault-tolerant operation method of the space-type DC/AC converter when controlling a switching tube in the space-type DC/AC converter to act.
Example 4
After an open circuit fault occurs in a single switching tube or a single diode in a space-type DC/AC converter comprising a switching capacitor sub-module, the embodiment provides a specific implementation mode of a fault-tolerant operation method of the space-type DC/AC converter;
Specifically, when an open circuit fault occurs in a single switching tube or a single diode at different positions, the switching tubes in the same state, the switching tubes kept on and the corresponding output level numbers in the switching tubes are as shown in the following table:
。
the embodiment uses a switch tube S 1 Or switch tube S 8 An example of an open circuit fault is described of a fault tolerant operation of a space-type DC/AC converter comprising a switched capacitor sub-module.
In one embodiment, theSwitch tube S of basic switch capacitor module 1 After an open circuit fault occurs, the states of the devices of the space type DC/AC converter including a switched capacitor sub-module at the output levels are as shown in the following table:
for the switches described in the foregoing in the same or complementary relationship, the state of only one of the switches is given, and "1" and "0" respectively represent the on and off states of the switch; "C", "D" and "C-are the charge, discharge and idle states of the capacitor, respectively.
As shown in fig. 8 (i) to 8 (v), a switching tube S is provided in the basic switched capacitor module 1 In the event of a fault, five modes of the space-type DC/AC converter comprising one switch capacitor sub-module are as follows:
Working mode I: switch tube S 5 Switch tube S 7 Switch tube S 9 And a switch tube S 11 On, the rest of the switch tubes are turned off, and the diode D 2 Conducting, wherein the rest diodes are in an idle state, and the output voltage U is 2E;
working mode II: switch tube S 2 Switch tube S 4 Switch tube S 7 Switch tube S 8 And a switch tube S 11 On, the rest of the switch tubes are turned off, and the diode D 2 Conducting, wherein the rest diodes are in an idle state, and the output voltage U is E;
working mode III: switch tube S 3 Switch tube S 5 Switch tube S 6 Switch tube S 9 And a switch tube S 11 On, the rest of the switch tubes are turned off, and the diode D 3 Conducting, wherein the rest diodes are in an idle state, and the output voltage U is 0;
working mode IV: switch tube S 3 Switch tube S 5 Switch tube S 6 Switch tube S 9 And a switch tube S 10 On, the rest of the switch tubes are turned off, and the diode D 3 On, the rest diodes are in idle state, outputThe voltage U is-E;
working mode V: switch tube S 3 Switch tube S 4 Switch tube S 6 Switch tube S 8 And a switch tube S 10 On, the rest of the switch tubes are turned off, and the diode D 3 The other diodes are in idle state, and the output voltage U is-2E.
Fig. 9 shows a switching tube S 1 Fault-tolerant operation of the space-type DC/AC converter comprising a switched capacitor sub-module o And load current I o With the change from the pre-fault state to the post-fault state, the capacitor C 1 In an idle state, switch tube S 4 And S is 8 S and S 5 And S is 9 While being turned on or off. As can be seen from fig. 9, the space-type DC/AC converter is quickly stabilized in a five-level operation state. Thus, the open-circuit fault tolerant operation capability of the space-type DC/AC converter was demonstrated.
The diode D of the basic switched capacitor module 1 In case of failure, switch tube S 1 In an idle state, the space type DC/AC converter comprising a switch capacitor sub-module is configured into five modes and outputs five levels; at this time, the state of each device of the space-type DC/AC converter under each output level is matched with the switching tube S of the basic switched capacitor module 1 The faults are the same, so this embodiment will not be described again.
In another embodiment, the switching tube S of the basic switched capacitor module 2 When in fault, the space type DC/AC converter comprising a switch capacitor sub-module is configured into three modes and outputs three levels; the states of the devices of the space-type DC/AC converter at the output levels are shown in the following table:
it can be appreciated that due to the switching tube S 5 And a switch tube S 6 In the same state at each output level, thus according to the aboveSwitch tube S in meter 6 Can deduce the state of the switching tube S 5 State of (2); due to the switching tube S 7 And a switch tube S 4 In the same state at each output level, thus according to the switching tube S in the table above 4 Can deduce the state of the switching tube S 7 State of (2); due to the switching tube S 9 And a switch tube S 8 In complementary state at each output level, thus according to the switching tube S in the table above 8 Can deduce the state of the switching tube S 9 State of (2); due to the switching tube S 11 And a switch tube S 10 In complementary state at each output level, thus according to the switching tube S in the table above 10 Can deduce the state of the switching tube S 11 Is a state of (2).
In another embodiment, the diode D of the basic switched capacitor module 2 In case of failure, switch tube S 2 In an idle state, the space type DC/AC converter comprising a switch capacitor sub-module is configured into three modes and outputs three levels; at this time, the state of each device of the space-type DC/AC converter under each output level is matched with the switching tube S of the basic switched capacitor module 2 The faults are the same, so this embodiment will not be described again.
In another embodiment, the switching tube S of the switch capacitor sub-module 3 When in fault, the space type DC/AC converter comprising a switch capacitor sub-module is configured into five modes and outputs five levels; the states of the devices of the space-type DC/AC converter at the respective output levels at this time are shown in the following table:
it can be appreciated that due to the switching tube S 5 And a switch tube S 4 In complementary state at each output level, thus according to the switching tube S in the table above 4 Can deduce the state of the switching tube S 5 State of (2); due to the switching tube S 7 And a switch tube S 10 In the same state at each output level, thus according to the table aboveMiddle switch tube S 10 Can deduce the state of the switching tube S 7 State of (2); due to the switching tube S 9 And a switch tube S 8 In complementary state at each output level, thus according to the switching tube S in the table above 8 Can deduce the state of the switching tube S 9 State of (2); due to the switching tube S 11 And a switch tube S 6 In the same state at each output level, thus according to the switching tube S in the table above 6 Can deduce the state of the switching tube S 11 Is a state of (2).
In another embodiment, the diode D of the switch capacitor sub-module 3 In case of failure, switch tube S 3 In an idle state, the space type DC/AC converter comprising a switch capacitor sub-module is configured into five modes and outputs five levels; at this time, the state of each device of the space-type DC/AC converter under each output level is matched with the switching tube S of the basic switched capacitor module 3 The faults are the same, so this embodiment will not be described again.
In another embodiment, the switching tube S of the basic switched capacitor module 4 When in fault, the space type DC/AC converter comprising a switch capacitor sub-module is configured into three modes and outputs three levels; the states of the devices of the space-type DC/AC converter at the respective output levels at this time are shown in the following table:
it can be appreciated that the switching tube S 5 Maintaining a conductive state at each output level; due to the switching tube S 7 And a switch tube S 6 In complementary state at each output level, thus according to the switching tube S in the table above 6 Can deduce the state of the switching tube S 7 State of (2); due to the switching tube S 9 And a switch tube S 8 In complementary state at each output level, thus according to the switching tube S in the table above 8 Can deduce the state of the switching tube S 9 State of (2); due to the switching tube S 11 And a switch tube S 10 In complementary state at each output level, thus according to the switching tube S in the table above 10 Can deduce the state of the switching tube S 11 Is a state of (2).
In another embodiment, the switching tube S of the basic switched capacitor module 5 When in fault, the space type DC/AC converter comprising a switch capacitor sub-module is configured into three modes and outputs three levels; the states of the devices of the space-type DC/AC converter at the respective output levels at this time are shown in the following table:
It can be appreciated that the switching tube S 4 Maintaining a conductive state at each output level; due to the switching tube S 7 And a switch tube S 6 In complementary state at each output level, thus according to the switching tube S in the table above 6 Can deduce the state of the switching tube S 7 State of (2); due to the switching tube S 9 And a switch tube S 8 In complementary state at each output level, thus according to the switching tube S in the table above 8 Can deduce the state of the switching tube S 9 State of (2); due to the switching tube S 11 And a switch tube S 10 In complementary state at each output level, thus according to the switching tube S in the table above 10 Can deduce the state of the switching tube S 11 Is a state of (2).
In another embodiment, the switching tube S of the switch capacitor sub-module 6 When in fault, the space type DC/AC converter comprising a switch capacitor sub-module is configured into three modes and outputs three levels; the states of the devices of the space-type DC/AC converter at the respective output levels at this time are shown in the following table:
it can be appreciated that due to the switching tube S 5 And a switch tube S 4 At each output levelComplementary state, thus according to the switching tube S in the table above 4 Can deduce the state of the switching tube S 5 State of (2); switch tube S 7 Maintaining a conductive state at each output level; due to the switching tube S 9 And a switch tube S 8 In complementary state at each output level, thus according to the switching tube S in the table above 8 Can deduce the state of the switching tube S 9 State of (2); due to the switching tube S 11 And a switch tube S 10 In complementary state at each output level, thus according to the switching tube S in the table above 10 Can deduce the state of the switching tube S 11 Is a state of (2).
In another embodiment, the switching tube S of the switch capacitor sub-module 7 When in fault, the space type DC/AC converter comprising a switch capacitor sub-module is configured into three modes and outputs three levels; the states of the devices of the space-type DC/AC converter at the respective output levels at this time are shown in the following table:
it can be appreciated that due to the switching tube S 5 And a switch tube S 4 In complementary state at each output level, thus according to the switching tube S in the table above 4 Can deduce the state of the switching tube S 5 State of (2); switch tube S 6 Maintaining a conductive state at each output level; due to the switching tube S 9 And a switch tube S 8 In complementary state at each output level, thus according to the switching tube S in the table above 8 Can deduce the state of the switching tube S 9 State of (2); due to the switching tube S 11 And a switch tube S 10 In complementary state at each output level, thus according to the switching tube S in the table above 10 Can deduce the state of the switching tube S 11 Is a state of (2).
In another embodiment, the switching tube S of the half bridge I 8 When open circuit fault occurs, switch tube S 9 The three electrolytic capacitors are normally charged in a conducting state, and the maximum output is achievedDuring the level period, at most two electrolytic capacitors are discharged in series; the space type DC/AC converter comprising one switch capacitor sub-module is configured into five modes and outputs five levels; the states of the devices of the space-type DC/AC converter at the output levels are shown in the following table:
as shown in fig. 10 (i) to 10 (v), a switching tube S is provided in the half bridge i 8 In the event of a fault, five modes of the space-type DC/AC converter comprising one switch capacitor sub-module are as follows:
working mode i: switch tube S 1 Switch tube S 5 Switch tube S 7 Switch tube S 9 And a switch tube S 11 On, the rest of the switch tubes are turned off, and the diode D 1 Conducting, wherein the rest diodes are in an idle state, and the output voltage U is 2E;
working mode ii: switch tube S 1 Switch tube S 5 Switch tube S 7 Switch tube S 9 And a switch tube S 10 On, the rest of the switch tubes are turned off, and the diode D 1 Conducting, wherein the rest diodes are in an idle state, and the output voltage U is E;
Working modality iii: switch tube S 2 Switch tube S 4 Switch tube S 7 Switch tube S 9 And a switch tube S 11 On, the rest of the switch tubes are turned off, and the diode D 2 Conducting, wherein the rest diodes are in an idle state, and the output voltage U is 0;
working modality iv: switch tube S 3 Switch tube S 5 Switch tube S 6 Switch tube S 9 And a switch tube S 10 On, the rest of the switch tubes are turned off, and the diode D 3 Conducting, wherein the rest diodes are in an idle state, and the output voltage U is-E;
operating mode v: switch tube S 3 Switch tube S 4 Switch tube S 6 Switch tube S 9 And a switch tube S 11 On, rest switchesTube off, diode D 3 The other diodes are in idle state, and the output voltage U is-2E.
In another embodiment, the switching tube S of the half bridge I 9 When in fault, the space type DC/AC converter comprising a switch capacitor sub-module is configured into five modes and outputs five levels; the states of the devices of the space-type DC/AC converter at the respective output levels at this time are shown in the following table:
it can be appreciated that due to the switching tube S 5 And a switch tube S 4 In complementary state at each output level, thus according to the switching tube S in the table above 4 Can deduce the state of the switching tube S 5 State of (2); due to the switching tube S 7 And a switch tube S 6 In complementary state at each output level, thus according to the switching tube S in the table above 6 Can deduce the state of the switching tube S 7 State of (2); switch tube S 8 Maintaining a conductive state at each output level; due to the switching tube S 11 And a switch tube S 10 In complementary state at each output level, thus according to the switching tube S in the table above 10 Can deduce the state of the switching tube S 11 Is a state of (2).
In another embodiment, the switching tube S of the half bridge II 10 When in fault, the space type DC/AC converter comprising a switch capacitor sub-module is configured into five modes and outputs five levels; the states of the devices of the space-type DC/AC converter at the respective output levels at this time are shown in the following table:
。
it can be appreciated that due to the switching tube S 5 And a switch tube S 4 In complementary state at each output level, thus according to the switching tube S in the table above 4 Can push the state of (2)Lead-out switch tube S 5 State of (2); due to the switching tube S 7 And a switch tube S 6 In complementary state at each output level, thus according to the switching tube S in the table above 6 Can deduce the state of the switching tube S 7 State of (2); due to the switching tube S 9 And a switch tube S 8 In complementary state at each output level, thus according to the switching tube S 8 Can deduce the state of the switching tube S 9 State of (2); switch tube S 11 The on state is maintained at each output level.
In another embodiment, the switching tube S of the half bridge II 11 When in fault, the space type DC/AC converter comprising a switch capacitor sub-module is configured into five modes and outputs five levels; the states of the devices of the space-type DC/AC converter at the respective output levels at this time are shown in the following table:
it can be appreciated that due to the switching tube S 5 And a switch tube S 4 In complementary state at each output level, thus according to the switching tube S in the table above 4 Can deduce the state of the switching tube S 5 State of (2); due to the switching tube S 7 And a switch tube S 6 In complementary state at each output level, thus according to the switching tube S in the table above 6 Can deduce the state of the switching tube S 7 State of (2); due to the switching tube S 9 And a switch tube S 8 In complementary state at each output level, thus according to the switching tube S 8 Can deduce the state of the switching tube S 9 State of (2); switch tube S 10 The on state is maintained at each output level.
Example 5
It should be noted that, when N is equal to or greater than 2, the open circuit fault tolerance strategy of the space type DC/AC converter is similar to that described in embodiments 3 and 4, and the characteristics thereof are described below.
When the switching tube in the charging loop has open-circuit fault, the corresponding electrolysis electricityWhen the capacitor is in a redundant state, a switching tube connected with the anode of the electrolytic capacitor in a charged state needs to be in an off state. Switching tube S of load side half bridge I 8 Connected switching tube S 1 When open circuit fault occurs, switch tube S 8 And S is equal to 4 (switch tube S) 9 And S is equal to 5 ) The state of (2) remains consistent; switching tube S connected with load side half bridge II 10 Connected switching tube S i3 When open circuit fault occurs, switch tube S 10 And S is equal to i7 (switch tube S) 11 And S is equal to i6 ) The state of (2) remains consistent; the number of output levels of the space-type DC/AC converter in both cases is 2n+3.
In addition, in the switching tube S 1 When an open circuit failure occurs, no capacitor is charged in a state where the output level is 2n+3. When the switching tube in the charging loop which is not connected with the switching tube at the load side has open-circuit fault, the two switching tubes which are connected with the positive electrode (negative electrode) of the corresponding electrolytic capacitor are in the same state, and the output level number of the space type DC/AC converter is 2N+1.
When the switching tube in the discharging loop has open-circuit fault, the switching tube in the complementary state with the switching tube in the normal working state is kept on. When the open-circuit fault occurs in the load side switching tube, the output level number of the space type DC/AC converter is 2N+3; when the non-load side switching tube has an open circuit fault, the output level number of the space type DC/AC converter is 2N+1.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention and not for limiting the same; while the invention has been described in detail with reference to the preferred embodiments, those skilled in the art will appreciate that: modifications may be made to the specific embodiments of the present invention or equivalents may be substituted for part of the technical features thereof; without departing from the spirit of the invention, it is intended to cover the scope of the invention as claimed.

Claims (9)

1. A space-type DC/AC converter, characterized by: comprises a direct current power supply E, a basic switch capacitor module and N switch capacitorsThe basic switched capacitor module comprises a switching tube S 1 Switch tube S 2 Switch tube S 4 Switch tube S 5 Diode D 1 Diode D 2 Electrolytic capacitor C 1 And an electrolytic capacitor C 2 The half bridge I comprises a switching tube S 8 And a switch tube S 9 The half bridge II comprises a switching tube S 10 And a switch tube S 11 ；
When n=1, the switch capacitor submodule comprises a switch tube S 3 Switch tube S 6 Switch tube S 7 Diode D 3 And an electrolytic capacitor C 3 ；
Switching tube S of basic switch capacitor module 1 Respectively with the input end of the switch tube S 2 Input terminal of the switch capacitor sub-module, switch tube S of the switch capacitor sub-module 3 Is connected with the positive pole of the DC power supply E, the switch tube S 1 Respectively with the output end of the switch tube S 4 Is connected with the input end of the electrolytic capacitor C 1 Is connected with the anode of the switch tube S 2 Respectively with the output end of the switch tube S 5 Input terminal of the switch capacitor sub-module, switch tube S of the switch capacitor sub-module 6 And an electrolytic capacitor C 2 Is connected with the anode of the battery; the switch tube S 4 The output ends of the switch capacitor sub-modules are respectively connected with a switch tube S of the switch capacitor sub-module 7 The diode D 2 Is connected with the input end of the electrolytic capacitor C 2 Is connected with the cathode of the switch tube S 5 Respectively with the output end of the diode D 1 Is connected with the input end of the electrolytic capacitor C 1 Is connected with the cathode of the battery;
switch tube S of switch capacitor sub-module 3 Respectively with the output end of the switch tube S 7 Is connected with the input end of the electrolytic capacitor C 3 Is connected with the anode of the switch tube S 6 Respectively with the output end of the diode D 3 And an electrolytic capacitor C 3 Is connected with the cathode of the battery;
the negative electrode of the direct current power supply E is respectively connected with a diode D of the basic switch capacitor module 1 Output of (2)Diode D 2 And diode D of said switched capacitor sub-module 3 Is connected with the output end of the power supply;
switching tube S of half bridge I 8 An electrolytic capacitor C of the basic switched capacitor module and the input terminal of the basic switched capacitor module 1 Is connected with the anode of the switch tube S 8 And the output end of the switch tube S 9 Is connected with the input end of the switch tube S 9 An output end of (C) and an electrolytic capacitor of the basic switch capacitor module 1 Is connected with the cathode of the battery; switching tube S of half-bridge II 10 An electrolytic capacitor C of the switch capacitor sub-module and the input terminal of the switch capacitor sub-module 3 Is connected with the anode of the switch tube S 10 And the output end of the switch tube S 11 Is connected with the input end of the switch tube S 11 An output terminal of the switch capacitor sub-module and an electrolytic capacitor C of the switch capacitor sub-module 3 Is connected with the cathode of the battery;
when N is more than or equal to 2, the ith switch capacitor submodule comprises an electrolytic capacitor C i3 Diode D i3 Switch tube S i3 Switch tube S i6 And a switch tube S i7 ，2≤i≤N；
Electrolytic capacitor C of ith switch capacitor sub-module i3 Electrolytic capacitor C with i-1 switch capacitor sub-module (i-1)3 Through a switching tube S i6 And a switch tube S i7 Cross-connect; electrolytic capacitor C of ith switch capacitor sub-module i3 The anode of (C) is also connected with a switch tube S i3 Is connected with the output end of the switch tube S i3 The input end of the base switch capacitor module is respectively connected with the positive electrode of the direct current power supply E and the switch tube S of the base switch capacitor module 1 Is connected with the input end of the switch tube S 2 Input terminal of (d) and switching tube S (i-1)3 Is connected with the input end of the power supply; electrolytic capacitor C of ith switch capacitor sub-module i3 And also with diode D i3 Is connected with the input end of diode D i3 Respectively connected with the negative electrode and the diode D of the direct current power supply E (i-1)3 Diode D of said basic switched capacitor module 1 Output of (D) and diode D 2 Is connected with the output end of the power supply;
n-th switch capacitor sub-dieElectrolytic capacitor C of block N3 Is connected with the switching tube S of the half bridge II 10 Is connected with the input end of the electrolytic capacitor C N3 And the switching tube S of the half bridge II 11 Is connected with the output end of the power supply.
2. A space-type DC/AC converter according to claim 1, characterized in that: switching tube S of basic switch capacitor module 4 And a switch tube S 5 Switch tube S of switch capacitor sub-module i6 And a switch tube S i7 Switching tube S of half bridge I and half bridge II 8 Switch tube S 9 Switch tube S 10 Switch tube S 11 Switching tube S of the basic switched capacitor module is a switching tube comprising a reverse diode 1 And a switch tube S 2 Switching tube S of the switched capacitor sub-module i3 Is a switching tube that does not include a reverse diode.
3. A modulation method of a space type DC/AC converter is characterized in that:
The space-type DC/AC converter of claim 1 or 2 is controlled to operate in 2n+5 modes by a driving signal, and 2n+5 levels are output: 0. (+) -E, + -2E, … …, + - (N+2) E; wherein N represents the number of switched capacitor sub-modules.
4. A method of modulating a space-type DC/AC converter according to claim 3, characterized by: by comparing sinusoidal modulation waves U when n=1 ref With six triangular carriers u a1 To u a6 Obtaining a logic signal u 1 To u 6 Will logic signal u 1 To u 6 After logic combination, the driving signals of the switching tubes are output and obtained, and the driving signal expression of each switching tube is as follows:
。
5. a method of fault tolerant operation of a space-type DC/AC converter as claimed in claim 1 or 2, characterized by:
switching tube S of basic switch capacitor module 1 When in fault, the space type DC/AC converter comprising a switch capacitor sub-module is controlled to work in five modes by a driving signal, and five levels are output: 0. + -E and + -2E;
switching tube S of basic switch capacitor module 2 Or switch tube S 4 Or switch tube S 5 When in fault, the space type DC/AC converter comprising a switch capacitor sub-module is controlled to work in three modes by a driving signal, and three levels are output: 0 and ± E;
Switching tube S of the switch capacitor sub-module 3 When in fault, the space type DC/AC converter comprising a switch capacitor sub-module is controlled to work in five modes by a driving signal, and five levels are output: 0. + -E and + -2E;
switching tube S of the switch capacitor sub-module 6 Or switch tube S 7 When in fault, the space type DC/AC converter comprising a switch capacitor sub-module is controlled to work in three modes by a driving signal, and three levels are output: 0 and ± E;
switching tube S of half bridge I 8 Or switch tube S 9 When in fault, the space type DC/AC converter comprising a switch capacitor sub-module is controlled to work in five modes by a driving signal, and five levels are output: 0. + -E and + -2E;
switching tube S in the half bridge II 10 Or switch tube S 11 When in fault, the space type DC/AC converter comprising a switch capacitor sub-module is controlled to work in five modes by a driving signal, and five levels are output: 0. + -E and + -2E.
6. The fault tolerant method of operation of a space-type DC/AC converter of claim 5 wherein: diode D in the basic switched capacitor module 1 In the event of a fault, the space-type DC/AC converter comprising one switched capacitor sub-module is configured into five modes and outputs five levels: 0. + -E and + -2E;
Diode D in the basic switched capacitor module 2 In the event of a fault, the space-type DC/AC converter comprising one switched capacitor sub-module is configured into three modes, and outputs three levels: 0 and ± E;
diode D in the switched capacitor sub-module 3 In the event of a fault, the space-type DC/AC converter comprising one switched capacitor sub-module is configured into five modes and outputs five levels: 0. + -E and + -2E.
7. A space-type DC/AC conversion system comprising a controller and a converter, characterized in that: the converter is a space-type DC/AC converter as claimed in claim 1 or 2.
8. The space-type DC/AC conversion system according to claim 7, wherein: the controller performs the steps of the modulation method of the space-type DC/AC converter according to claim 3 or 4 when controlling the switching tube in the space-type DC/AC converter to operate.
9. A fault tolerant system for a space-based DC/AC converter comprising a controller and a space-based DC/AC converter, characterized by: the controller performs the steps of the fault-tolerant operation method of the space-type DC/AC converter according to claim 5 or 6 when controlling the switching tube in the space-type DC/AC converter to operate.
CN202210183909.XA 2022-02-28 2022-02-28 Space type DC/AC converter and fault-tolerant operation method thereof Active CN114553038B (en)

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