CN203377805U - Diode neutral-point-clamped three-level converter - Google Patents
Diode neutral-point-clamped three-level converter Download PDFInfo
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- CN203377805U CN203377805U CN201320490488.1U CN201320490488U CN203377805U CN 203377805 U CN203377805 U CN 203377805U CN 201320490488 U CN201320490488 U CN 201320490488U CN 203377805 U CN203377805 U CN 203377805U
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- diodes
- clamped
- diode
- point
- neutral
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Abstract
The utility model relates to a diode neutral-point-clamped three-level converter. Each bridge arm is provided with two switch elements IGBT (Sa11, Sa21), which are corresponding to two freewheeling diodes (Da11, Da21) and two clamping diodes (Da1, Da2), and two uncontrollable rectifier diodes (Da31, Da41). The uncontrollable rectifier diodes and neutral points of the switch elements of the bridge arm in each phase are connected with neutral points of direct current side capacitors through the clamping diodes, so that the output voltage is clamped to the direct current side neutral point potential. When the switch tubes Sa11 and Sa21 are turned on, the A-phase input end of a rectifier is clamped to the neutral point potential 0. When the two switch tubes are turned off, if the A phase current is positive, the A phase input of the rectifier is connected to the negative electrode of a direct current bus through the diodes Da21 and Da41 and the input end potential is clamped to -Udc/2. The diode neutral-point-clamped three-level converter has the advantages that the time of potential balance is reduced, the harmonic waves of the direct current bus are reduced, the filter capacitance is reduced, the cost is reduced, the software design is simplified, and the control difficulty is reduced.
Description
Technical field
The utility model relates to diode neutral point clamp three-level current transformer, belongs to circuit field.
Background technology
Traditional diode neutral point clamp three-level current transformer structure as shown in Figure 1, there is the unbalanced shortcoming of midpoint potential in this structure, if employing software solution, can not get back in a short period of time balance point when unbalance of neutral-point voltage is very large, simultaneously because increased the algorithm of balance midpoint potential, the control difficulty strengthens, and also can have influence on the waveform of output voltage and electric current, increases harmonic content.
The utility model content
The utility model has improved hardware circuit, makes the time shorten of potential balance, and the harmonic wave of DC bus reduces, and therefore can suitably reduce the size of filter capacitor, cost is decreased, and simplified Software for Design, has reduced the control difficulty.
The disclosed a kind of diode neutral point clamp three-level current transformer of the utility model, brachium pontis has 2 switch element IGBT (S
a11, S
a21), corresponding 2 fly-wheel diode (D
a11, D
a21) and 2 clamping diode (D
a1, D
a2) and two uncontrollable rectifier diode (D
a31, D
a41); The uncontrollable rectifier diode of every brachium pontis and the mid point of switch element are connected by the mid point of clamping diode and DC bus capacitor, and output voltage is clamped on the DC side midpoint potential.As switching tube S
a11, S
a21during conducting, the A phase input of rectifier is clamped at midpoint potential 0.When two switching tubes all turn-off, if the A phase current for just, the A of rectifier inputs mutually through diode D
a21, D
a41be connected to the negative pole of DC bus, be clamped at-U of input current potential
dc/ 2; In like manner, if the A phase current is negative, the A of rectifier inputs mutually through diode D
a31, D
a11be connected to the positive pole of DC bus, the input current potential is clamped at U
dc/ 2.
The accompanying drawing explanation
Describe in more detail exemplary embodiment of the present utility model by the reference accompanying drawing, above and other aspect of the present utility model and advantage will become and more be readily clear of, in the accompanying drawings:
The electrical block diagram that Fig. 1 is traditional diode neutral point clamp three-level current transformer;
The electrical block diagram of the embodiment 1 that Fig. 2 is diode neutral point clamp three-level current transformer of the present utility model;
The electrical block diagram of the embodiment 2 that Fig. 3 is diode neutral point clamp three-level current transformer of the present utility model.
Embodiment
Hereinafter, now with reference to accompanying drawing, the utility model is described more fully, various embodiment shown in the drawings.Yet the utility model can be implemented in many different forms, and should not be interpreted as being confined to embodiment set forth herein.On the contrary, it will be thorough with completely providing these embodiment to make the disclosure, and scope of the present utility model is conveyed to those skilled in the art fully.
Hereinafter, exemplary embodiment of the present utility model is described with reference to the accompanying drawings in more detail.
With reference to accompanying drawing 2, rectifying part is identical with the Converting Unit structure, and the rectifying part A of take is example mutually, and brachium pontis has 4 switch element IGBT (S
a11, S
a21, S
a31, S
a41), corresponding 4 fly-wheel diode (D
a11, D
a21, D
a31, D
a41) and 2 clamping diode (D
a1, D
a2); Two capacitor C that have the appearance value to equate in DC side
1, C
2, the voltage of getting on each electric capacity is U
dc/ 2, U wherein
dcfor DC voltage.In order to suppress the mid-point voltage fluctuation, in DC side, 3 switch element IGBT (S have been added
y1, S
y2, S
y3), two diode (D
1, D
2), and two energy storage inductor (L
3, L
4); The mid point of every brachium pontis two switch elements is connected by the mid point of clamping diode and DC bus capacitor, and output voltage is clamped on the DC side midpoint potential.Concrete equilibrium principle is as follows:
(1) DC side busbar voltage U
dcthe balance of the midpoint potential under the situation that remains unchanged:
If U
dcremain unchanged, U
dc=U
c1+ U
c2for constant, U
c1increase must cause U
c2descend, same U
c1decline must make U
c2increase, therefore can carry out the balance midpoint potential by the voltage of adjusting two discrete capacitor of DC side.For realizing this goal, make S
y3all the time in conducting state, at this moment circuit is comprised of Boost and Buck converter.S
y1, D
1, L
3and C
2form the Buck converter; S
y2, D
2, L
4and C
1form the Boost converter.The mode of operation of circuit correspondingly is divided into Buck pattern conversion and Boost pattern conversion.The operating state of these two kinds of pattern conversions should be complementary.Work as U
c1>U
c2the time, the Buck translation circuit is started working, and now the Boost translation circuit quits work.In the Buck pattern conversion, be by adjusting C
2the voltage at two ends realizes suppressing the S that works as of mid-point potential offset
y1during conducting, on the one hand at U
dcunder effect, the electric current S that flows through
y1, L
3, C
2, capacitor C on the other hand
1on voltage U
c1through S
y1with L
3form loop, all make inductance L
3energy storage; Work as S
y1during shutoff, through C
2, D
1, L
3loop will be stored in L
3in electric energy be transformed into C
2in, capacitor C
2charging, on it, voltage increases, until C
1with C
2on the balance of voltage.Work as U
c2>U
c1the time, the Buck converter is no longer worked, and the Boost translation circuit is started working.Due to U
c2>U
c1, C
2in energy by indirect branch to C
1in.Work as S
y2during conducting, one side C
2on voltage U
c2through L
4, S
y2electric discharge, stored energy is at L
4in, U on the other hand
dcthrough C
1and C
2redistribute voltage; Work as S
y2during shutoff, diode D
2conducting, be stored in L
4in energy pass through D
2transfer to C
1in.Like this, in the Boost pattern conversion, by adjusting C
1the voltage at two ends just can suppress the skew of midpoint potential, until U
c1=U
c2.
(2) DC side busbar voltage U
dcreduce the balance of the midpoint potential under situation:
Cause U when pulsation occurs input power
dcwhile being decreased to lower than the voltage protection set point, the S in circuit
y3pipe turn-offs, and now Boost and Buck converter are worked simultaneously, not only make C
1, C
2on the balance of voltage, and the U that makes their voltage sum equal to set
dcvalue.The Buck converter is adjusted capacitor C
2the voltage at two ends, S
y1during conducting, from U
dcthe electric current the flowed out S that flows through
y1, L
3, C
2, make L
3energy storage; S
y1during shutoff, L
3in power conversion to C
2in.Meanwhile, the Boost converter by energy from C
2be transformed into C
1in, adjust C
1the voltage at two ends, its course of work is identical with above-mentioned Boost pattern conversion.
For such scheme, greatly increased circuit devcie, in order to solve in circuit the problem that device increases, this programme proposes:
1), by the generator unit stator winding is reasonably designed, utilize the equivalent inductance of generator unit stator winding to replace L
3, L
4energy-storage travelling wave tube, without extra, heavy huge inductance device again.In order more to simplify circuit arrangement, the inductance in filter circuit is also replaced with the generator unit stator winding simultaneously.
2) because be direct-drive wind power system, the rectification side converter does not need the two-way flow of energy, so also can simplify improvement to the rectification side.
As shown in Figure 3, the A of take is example to final circuit after improvement mutually, and brachium pontis has 2 switch element IGBT (S
a11, S
a21), corresponding 2 fly-wheel diode (D
a11, D
a21) and 2 clamping diode (D
a1, D
a2) and two uncontrollable rectifier diode (D
a31, D
a41); The uncontrollable rectifier diode of every brachium pontis and the mid point of switch element are connected by the mid point of clamping diode and DC bus capacitor, and output voltage is clamped on the DC side midpoint potential.As switching tube S
a11, S
a21during conducting, the A phase input of rectifier is clamped at midpoint potential 0.When two switching tubes all turn-off, if the A phase current for just, the A of rectifier inputs mutually through diode D
a21, D
a41be connected to the negative pole of DC bus, be clamped at-U of input current potential
dc/ 2; In like manner, if the A phase current is negative, the A of rectifier inputs mutually through diode D
a31, D
a11be connected to the positive pole of DC bus, the input current potential is clamped at U
dc/ 2.
The beneficial effect that technical solutions of the utility model are brought:
Solved diode neutral point clamp three-level current transformer DC side midpoint potential imbalance problem, and the reduction of the complexity of circuit, operating cost reduced.
The foregoing is only embodiment of the present utility model, be not limited to the utility model.The utility model can have various suitable changes and variation.All any modifications of doing, be equal to replacement, improvement etc., within all should being included in protection range of the present utility model within spirit of the present utility model and principle.
Claims (2)
1. diode neutral point clamp three-level current transformer is characterized in that:
A mutually in, brachium pontis has 2 switch element IGBT, corresponding 2 fly-wheel diodes and 2 clamping diodes and two uncontrollable rectifier diodes; The uncontrollable rectifier diode of every brachium pontis and the mid point of switch element are connected by the mid point of clamping diode and DC bus capacitor.
2. diode neutral point clamp three-level current transformer is characterized in that:
The rectifying part of described current transformer is identical with the Converting Unit structure, rectifying part A mutually in, brachium pontis has 4 switch element IGBT, corresponding 4 fly-wheel diodes and 2 clamping diodes; Two capacitor C that have the appearance value to equate in DC side
1, C
2, possess 3 switch element IGBT in DC side, two diodes, and two energy storage inductors; The mid point of every brachium pontis two switch elements is connected by the mid point of clamping diode and DC bus capacitor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320490488.1U CN203377805U (en) | 2013-08-09 | 2013-08-09 | Diode neutral-point-clamped three-level converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320490488.1U CN203377805U (en) | 2013-08-09 | 2013-08-09 | Diode neutral-point-clamped three-level converter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203377805U true CN203377805U (en) | 2014-01-01 |
Family
ID=49840306
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201320490488.1U Expired - Fee Related CN203377805U (en) | 2013-08-09 | 2013-08-09 | Diode neutral-point-clamped three-level converter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203377805U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104253549A (en) * | 2014-10-11 | 2014-12-31 | 东南大学 | LCL filtering-based circuit topology structure of high-power PWM (pulse-width modulation) rectifier |
| CN104506065A (en) * | 2015-01-12 | 2015-04-08 | 佛山市柏克新能科技股份有限公司 | Midpoint potential control method of three-level inverter |
| WO2023096252A1 (en) * | 2021-11-24 | 2023-06-01 | 경북대학교 산학협력단 | Three-level npc converter using zigzag transformer for reducing capacitor ripple |
-
2013
- 2013-08-09 CN CN201320490488.1U patent/CN203377805U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104253549A (en) * | 2014-10-11 | 2014-12-31 | 东南大学 | LCL filtering-based circuit topology structure of high-power PWM (pulse-width modulation) rectifier |
| CN104506065A (en) * | 2015-01-12 | 2015-04-08 | 佛山市柏克新能科技股份有限公司 | Midpoint potential control method of three-level inverter |
| WO2023096252A1 (en) * | 2021-11-24 | 2023-06-01 | 경북대학교 산학협력단 | Three-level npc converter using zigzag transformer for reducing capacitor ripple |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20140101 Termination date: 20150809 |
|
| EXPY | Termination of patent right or utility model |