CN106787917A - A kind of NP complementary type SVPWM control methods of three-phase tri-level inverter - Google Patents

Abstract

The present invention provides a kind of NP complementary type SVPWM control methods of three-phase tri-level inverter.The present invention by separating inverter N-type small vector and p-type small vector, and respectively with 6 big vector 6 middle vectors composition N-type and p-type SVPWM control methods.Different control combination control realizations of the N-type from p-type SVPWM control method in different operating interval are basically identical, only on off sequence slightly has difference three-level inverter control method of the invention in the case of same sinusoidal line voltage is exported, compared with SVPWM control strategies, single N-type or p-type control used circuit mode quantity reduction 1/4. compared with seven segmentation SVPWM, the power switch pipe on-off times of three-phase inverter reduce 1/3, so as to significantly reduce switching frequency and the loss of three-phase inverter.On the other hand, because single control program is using only N-type or p-type small vector, for seven each on off sequence of segmentation SVPWM are comprising NP type vectors, alignment current potential is adjusted faster, and effect also becomes apparent from.

Description

A kind of NP complementary type SVPWM control methods of three-phase tri-level inverter

Technical field

It is especially a kind of to be based on N-type and p-type SVPWM the present invention relates to a kind of control method of three-phase tri-level inverter Control the control method for combining.

Background technology

With the increase of inverter power, and the switching frequency of power switch pipe raising, the switching loss of switching tube It is increasing, it has also become a key issue of restriction high power density inverter development, therefore, multi-electrical level inverter is gradually Main flow as commercial Application.Wherein, three-level inverter is due to characteristic good and control is relatively simple, extensively should obtain With.

Space vector modulation technique (SVPWM) is that a kind of foundation synthesizes notional pulsewidth modulation side in space voltage vector Method, has been widely used in power electronics modulation.Its core concept be exactly using the different on off states of converter as Basic role vector, according to selected basic vector and its specific action time come synthesized reference vector.Compared to common PWM algorithm, it has the advantages that many prominent：The utilization rate of voltage is high, is easy to Digital Realization, and output waveform quality is good, Close to sine, reasonable arrangement space vector can reduce switching frequency, reduce switching loss.Under SVPWM modulation, three level are inverse Become device three-phase bridge arm per mutually there is three (2-1-0) on off states, whole system just has 27 kinds of on off states, be divided into big vector, in Vector, small vector and zero vector.Vector does not have Redundanter schalter state in big vector, and zero vector and small vector have redundancy shape State；For the electric current of midpoint, zero vector and the corresponding midpoint electric current of big vector are zero, although middle vector being capable of alignment current potential Produce influence, yet with and in the absence of redundant state, therefore middle vector can not participate in neutral balance control.Profit is considered for this Controlled with unnecessary small vector, it is general to make waveform symmetrical in a controlling cycle using the method for changing order of action.By It is using redundancy small vector alignment in the method that Traditional Space voltage vector modulating mode is all based on seven segmentation modulating modes The effect of potential balance, the control of alignment current potential is still limited, and control strategy is extremely complex.

The content of the invention

It is an object of the invention to the traditional level SVPWM control strategy of seven segmentation three of simplification, and propose a kind of based on three electricity The NP complementary type SVPWM control methods of flat three-phase inverter, concrete technical scheme is as follows.

A kind of NP complementary type SVPWM control methods of three-level three-phase inverter, it is by by three-level three-phase inverter 24 operation modes are divided, by separating three-level three-phase inverter N-type small vector and p-type small vector, N-type small vector with 6 big middle vectors of vector 6 constitute N-type control method, and p-type small vector and 6 big middle vectors of vector 6 constitute p-type SVPWM control method, and two kinds of control methods are connected as independent control strategy the need for only relying on midpoint potential, Two kinds of control methods are realized in the interval various combination of different operating and switching control.

Further, the NP complementary type SVPWM control methods of three-level three-phase inverter specifically include following steps：

1) big sector where needing the phase angle of the voltage vector of output to determine it by three-phase tri-level inverter, further divides The length and angle relationship for analysing reference vector obtain residing small delta-shaped region；

2) the small delta-shaped region according to residing for, selects three operation modes of corresponding three-phase tri-level inverter, really The working time of fixed each operation mode；

3) three switching sequences of operation mode of working time generation according to each operation mode, according to switching sequence Row three operation mode synthesized voltage vectors of control, make three operation modes by the circular trace rotation output three-phase of reference vector The sinusoidal line voltage of three-level inverter；

4) by alignment current potential and the sample detecting of each phase current, determine that current time need to use N-type or p-type SVPWM control method.

Further, interval in linear work in the above method, N-type SVPWM control method operation mode only has 6 greatly Vector is (200,220,020,022,002,202), and 6 middle vectors are (210,120,021,012,102,201), and 6 N-types are small Vector is (100,110,010,011,001,101), and the operation interval can be divided into 6 big sectors, including：Sector S₁, 0 ° of correspondence ~60 °；Sector S₂, 60 °~120 ° of correspondence；Sector S₃, 120 °~180 ° of correspondence；Sector S₄, 180 °~240 ° of correspondence；Sector S₅, 240 °~300 ° of correspondence；Sector S₆, 300 °~360 ° of correspondence；6 big sectors can be again 4 small deltas, and partitioning standards are by this Each vector distal point line of operation interval is constituted, and each big sector dividing mode is consistent, and is centrosymmetric, and specific region is drawn The situation of dividing is as shown in Figure 3.

P-type SVPWM control method operation mode only has 6 big vectors i.e. (200,220,020,022,002,202), 6 Middle vector is (210,120,021,012,102,201), and 6 p-type small vectors are (211,221,121,122,112,212), should Operation interval can be divided into 6 big sectors, including：Including：Sector S₁, 0 °~60 ° of correspondence；Sector S₂, 60 °~120 ° of correspondence；Sector S₃, 120 °~180 ° of correspondence；Sector S₄, 180 °~240 ° of correspondence；Sector S₅, 240 °~300 ° of correspondence；Sector S₆, 300 ° of correspondence ~360 °；6 big sectors can be again 4 small deltas, and partitioning standards are by each vector distal point line structure by the operation interval Into each big sector dividing mode is consistent, and is centrosymmetric, and specific region division situation is as shown in Figure 4.

Two kinds of control method difference only in the difference of small vector, therefore, the step 1,2 is homogeneous in two kinds of control methods Cause, difference is only in the difference of on off sequence.

Further, above method step 2) in, reference voltage vector is U_ref, θ is U_refWith the reality of α axles in SVPWM Position angle, θ₀It is U_refRelative position angle, inverter DC bus-bar voltage be U_dc, the judgement side of big sector where reference vector Method is as follows：

1) whenWhen, U_ref∈S₁, U_refThe relative position angle θ of the big sector of place triangle₀=θ；

2) whenWhen, U_ref∈S₂, U_refThe relative position angle of the big sector of place triangle

3) whenWhen, U_ref∈S₃, U_refThe relative position angle of the big sector of place triangle

4) whenWhen, U_ref∈S₄, U_refThe relative position angle θ of the big sector of place triangle₀=θ-π；

5) whenWhen, U_ref∈S₅, U_refThe relative position angle of the big sector of place triangle

6) whenWhen, U_ref∈S₆, U_refThe relative position angle of the big sector of place triangle

Small delta-shaped region can be by relative position angle θ where reference vector₀And the length of reference vector determines jointly：

Judge that rule is as shown in table 1 below, in table in Y expressions the rule of correspondence set up, in N expressions the rule of correspondence not into It is vertical ,-represent unrelated；

Table 1

Further, above method step 2) in, when selecting used space voltage vector, due to N-type or p-type SVPWM control method all only used the small vector of half, therefore only be needed three according to where reference voltage vector during selection vector Angular domain, three voltage vectors that selection closes on come Fitted reference voltage vector, specific vector selection scheme such as Fig. 3, Fig. 4 It is shown.

According to the space voltage vector selected, each sky can determine that by the length and relative position angle of reference voltage vector Between vector action time：

1) when reference voltage vector is in small triangle 1, reference voltage vector is by small vector U₁, small vector U₂And null vector Amount U₀Synthesis, each vector specific action time is as follows：

2) when reference voltage vector is in small triangle 2, reference voltage vector is by small vector U₁, small vector U₂And middle arrow Amount U₃Synthesis, each vector specific action time is as follows：

3) when reference voltage vector is in small triangle 3, reference voltage vector is by small vector U₁, middle vector U₂And big arrow Amount U₃Synthesis, each vector specific action time is as follows：

4) when reference voltage vector is in small triangle 4, reference voltage vector is by small vector U₁, middle vector U₂And big arrow Amount U₃Synthesis, each vector specific action time is as follows：

Further, step 3 described in the above method) in, it is considered to the continuity and symmetry of on off sequence, major sectors On off sequence be defined below：

For N-type SVPWM control method, its switching sequence is:

Table 2

For p-type SVPWM control method, its switching sequence is:

Table 3

Further, in the above method, for N-type or p-type SVPWM control method, each is all only with 18 works Control is switched over as mode；NP complementary type SVPWM control modes are electric in an output compared to traditional SVPWM control strategies On-off times reduce 1/3 in the pressure cycle.

Compared with prior art, the invention has the advantages that and technique effect：

This method simplifies the switching of traditional SVPWM control strategies by N, two kinds of combinations of SVPWM control method of p-type Sequence, compared with prior art, the invention has the advantages that：1. for same carrier frequency, its power tube on-off times 1/3 is reduced than SVPWM controls；2. a kind of realization of single control method is simple compared with SVPWM, and clear thinking, alignment electricity The regulation and control of position are swift in response.

Brief description of the drawings

Fig. 1 is the circuit topological structure figure of three-level three-phase inverter；

Fig. 2 is the N-type and p-type SVPWM control method vector distribution map of three-level three-phase inverter；

Fig. 3 is that three-level three-phase inverter N-type SVPWM control method acts on schematic vector diagram in regional；

Fig. 4 is that three-level three-phase inverter p-type SVPWM control method acts on schematic vector diagram in regional；

Fig. 5 is mid-point voltage waveform of the three-level three-phase inverter under N-type SVPWM controls；

Fig. 6 is mid-point voltage waveform of the three-level three-phase inverter under p-type SVPWM controls；

Fig. 7 is line voltage waveform of the three-level three-phase inverter under NP complementary types SVPWM controls；

Fig. 8 is three-level three-phase inverter midpoint potential waveform under NP complementary types SVPWM controls；

Fig. 9 is three-level three-phase inverter midpoint potential in single-phase impact double-charge under NP complementary types SVPWM is controlled Fluctuation situation.

Specific implementation method

The following is combination three-level three-phase inverter NP complementary type SVPWM control methods to the specific of technical solution of the present invention Implementation is described in further detail, but implementation of the invention and protection domain not limited to this.If it is noted that following have not special Not Xiang Xishuoming process or parameter, be that those skilled in the art can refer to and understand in prior art (SVPWM) or realize.

Fig. 1 is the circuit topological structure figure of three-level three-phase inverter, and circuit is constituted and non-invention design, therefore herein Need not repeat, component symbol therein is also general code symbol.Each phase level shape of three-level three-phase inverter circuit topology The corresponding on off state of state is as shown in table 4.

Table 4

As shown in Fig. 2 interval in linear work, N-type SVPWM control method operation mode only have 6 big vectors (200, 220,020,022,002,202), 6 middle vectors (210,120,021,012,102,201), 6 N-type small vectors (100,110, 010,011,001,101).P-type SVPWM control method operation mode only have 6 big vectors (200,220,020,022,002, 202), 6 middle vectors (210,120,021,012,102,201), 6 p-type small vectors (211,221,121,122,112, 212).According to midpoint potential and three-phase current in each switch periods T_sThe suitable SVPWM control method of interior selection, by joining Examine three voltage vectors where voltage representated by delta-shaped region summit and be combined into the reference voltage vector of inverter, and make it Rotated by circular trace, so as to obtain three phase sine line voltage output as shown in Figure 7.

Assuming that reference voltage vector is U_ref, the NP complementary type SVPWM control methods of three-level three-phase inverter realize step It is as follows：

1. it is interval where reference voltage vector to determine

1. the judgement of big sector where reference voltage vector

Vector includes amplitude and phase angle, and sector where therefore referring to voltage vector can be determined by phase angle.It is implemented as follows：

Wherein, θ is U_refWith the actual bit angle setting of α axles, S₁, S₂, S₃, S₄, S₅And S₆Big sector 1~6, θ are represented respectively₀It is U_refRelative position angle.

2. the judgement of small delta-shaped region where reference voltage vector

Determine after big sector where reference voltage vector, the judgement of zonule is needed by U_refAnd θ₀To be judged. Small delta-shaped region residing for reference voltage vector can be by the length of reference voltage vector and its relative position angle θ₀By such as Lower rule judgment：

Judge rule as shown in table 1, " Y " represents that the rule of correspondence is set up in table, " N " represents that the rule of correspondence is invalid, "-" table Show unrelated.

1st, the working time determination of operation mode：

With reference to N-type, the symmetry of the vector distribution map of p-type SVPWM control method, the time of major sectors is only needed by joining Examine the length and relative position angle θ of vector₀Can determine that, make a concrete analysis of as follows：

As shown in Fig. 3, Fig. 4 triangle row 1, when reference vector is that reference voltage vector is in small delta-shaped region 1, reference Voltage vector is mode U by two small vectors₁With mode U₂Follow, then have U_refT_s=U₁T₁+U₂T₂, wherein T₁It is mode U₁Work Time；T₂It is mode U₂Working time, and have T_s=T₁+T₂+T₀, T₀It is mode U₁、U₂When not working, inverter three-phase bridge arm is equal Working time in zero potential.If U_refRelative position angle be θ₀, inverter DC bus-bar voltage is U_dcThen have：

Mode U can determine that by above formula₁、U₂And U₀Time it is as follows：

As shown in Fig. 3, Fig. 4 triangle row 2, if reference voltage vector U_refDuring positioned at small delta-shaped region 2, reference voltage Vector is by two small vector U₁, U₂With a middle vector U₃Synthesis, its working time can be determined by following formula：

Solution is obtained：

As shown in Fig. 3, Fig. 4 triangle row 3, if reference voltage vector U_refDuring positioned at small delta-shaped region 3, reference voltage Vector is by a small vector U₁, a middle vector U₂With a big vector U₃Synthesis, its working time can be determined by following formula：

Solution can be obtained：

As shown in Fig. 3, Fig. 4 triangle row 4.If reference voltage vector U_refDuring positioned at small delta-shaped region 4, reference voltage Vector is by a small vector U₁, a middle vector U₂With a big vector U₃Synthesis, its working time can be determined by following formula：

Solution can be obtained：

2nd, the switching sequence generation of operation mode

Determine after small delta-shaped region each vector working time, each interval on off sequence is specific as follows with determination：

For N-type SVPWM control method, its switching sequence is:

Big sector S₁：1) delta 1, on off sequence is:

100(T₁/2)-110(T₂/2)-111(T₀)-110(T₂/2)-100(T₁/2)；

2) delta 2, on off sequence is:

100(T₁/2)-110(T₂/2)-210(T₃)-110(T₂/2)-110(T₁/2)

3) delta 3, on off sequence is:

110(T₁/2)-210(T₂/2)-220(T₃)-210(T₂/2)-110(T₁/2)

4) delta 4, on off sequence is:

100(T₁/2)-200(T₃/2)-210(T₂)-200(T₃/2)-100(T₁/2)

Big sector S₂：1) delta 1, on off sequence is:

010(T₂/2)-110(T₁/2)-111(T₀)-110(T₁/2)-010(T₂/2)；

2) delta 2, on off sequence is:

010(T₂/2)-110(T₁/2)-120(T₃)-110(T₁/2)-010(T₂/2)

3) delta 3, on off sequence is:

010(T₁/2)-020(T₃/2)-120(T₂)-020(T₃/2)-010(T₁/2)

4) delta 4, on off sequence is:

110(T₁/2)-120(T₂/2)-220(T₃)-120(T₂/2)-110(T₁/2)

Big sector S₃：1) delta 1, on off sequence is:

010(T₁/2)-011(T₂/2)-011(T₀)-011(T₂/2)-010(T₁/2)；

2) delta 2, on off sequence is:

010(T₁/2)-011(T₂/2)-021(T₃)-011(T₂/2)-010(T₁/2)

3) delta 3, on off sequence is:

011(T₁/2)-021(T₂/2)-022(T₃)-021(T₂/2)-011(T₁/2)

4) delta 4, on off sequence is:

010(T₁/2)-020(T₃/2)-021(T₂)-020(T₃/2)-010(T₁/2)

Big sector S₄：1) delta 1, on off sequence is:

001(T₂/2)-011(T₁/2)-111(T₀)-011(T₁/2)-001(T₂/2)；

2) delta 2, on off sequence is:

001(T₂/2)-011(T₁/2)-012(T₃)-011(T₁/2)-001(T₂/2)

3) delta 3, on off sequence is:

001(T₁/2)-002(T₃/2)-012(T₂)-002(T₃/2)-001(T₁/2)

4) delta 4, on off sequence is:

011(T₁/2)-012(T₂/2)-022(T₃)-012(T₂/2)-022(T₁/2)

Big sector S₅：1) delta 1, on off sequence is:

001(T₁/2)-101(T₂/2)-111(T₀)-101(T₂/2)-001(T₁/2)；

2) delta 2, on off sequence is:

001(T₁/2)-101(T₂/2)-102(T₃)-101(T₂/2)-001(T₁/2)

3) delta 3, on off sequence is:

101(T₁/2)-102(T₂/2)-202(T₃)-102(T₂/2)-101(T₁/2)

4) delta 4, on off sequence is:

001(T₁/2)-002(T₃/2)-102(T₂)-002(T₃/2)-001(T₁/2)

Big sector S₆：1) delta 1, on off sequence is:

100(T₂/2)-101(T₁/2)-111(T₀)-101(T₁/2)-100(T₂/2)；

2) delta 2, on off sequence is:

100(T₂/2)-101(T₁/2)-201(T₃)-101(T₁/2)-100(T₂/2)

3) delta 3, on off sequence is:

100(T₁/2)-200(T₃/2)-201(T₂)-200(T₃/2)-100(T₁/2)

4) delta 4, on off sequence is:

101(T₁/2)-201(T₂/2)-202(T₃)-201(T₂/2)-101(T₁/2)

For p-type SVPWM control method, its switching sequence is:

Big sector S₁：1) delta 1, on off sequence is:

221(T₂/2)-211(T₁/2)-111(T₀)-211(T₁/2)-221(T₂/2)；

2) delta 2, on off sequence is:

221(T₂/2)-211(T₁/2)-210(T₃)-211(T₁/2)-221(T₂/2)

3) delta 3, on off sequence is:

221(T₁/2)-220(T₃/2)-210(T₂)-220(T₃/2)-221(T₁/2)

4) delta 4, on off sequence is:

211(T₁/2)-210(T₂/2)-220(T₃)-210(T₂/2)-211(T₁/2)

Big sector S₂：1) delta 1, on off sequence is:

221(T₁/2)-121(T₂/2)-111(T₀)-121(T₂/2)-221(T₁/2)；

2) delta 2, on off sequence is:

221(T₁/2)-121(T₂/2)-120(T₃)-121(T₂/2)-221(T₁/2)

3) delta 3, on off sequence is:

121(T₁/2)-120(T₂/2)-220(T₃)-120(T₂/2)-121(T₁/2)

4) delta 4, on off sequence is:

221(T₁/2)-220(T₃/2)-120(T₂)-220(T₃/2)-221(T₁/2)

Big sector S₃：1) delta 1, on off sequence is:

122(T₂/2)-121(T₁/2)-111(T₀)-121(T₁/2)-122(T₂/2)；

2) delta 2, on off sequence is:

122(T₂/2)-121(T₁/2)-021(T₃)-121(T₁/2)-122(T₂/2)

3) delta 3, on off sequence is:

122(T₁/2)-022(T₃/2)-021(T₂)-022(T₃/2)-122(T₁/2)

4) delta 4, on off sequence is:

121(T₁/2)-021(T₂/2)-020(T₃)-021(T₂/2)-121(T₁/2)

Big sector S₄：1) delta 1, on off sequence is:

122(T₁/2)-112(T₂/2)-111(T₀)-112(T₂/2)-122(T₁/2)；

2) delta 2, on off sequence is:

122(T₁/2)-112(T₂/2)-012(T₃)-112(T₂/2)-122(T₁/2)

3) delta 3, on off sequence is:

112(T₁/2)-012(T₂/2)-002(T₃)-012(T₂/2)-112(T₁/2)

4) delta 4, on off sequence is:

122(T₁/2)-022(T₃/2)-012(T₂)-022(T₃/2)-122(T₁/2)

Big sector S₅：1) delta 1, on off sequence is:

212(T₂/2)-112(T₁/2)-111(T₀)-112(T₁/2)-212(T₂/2)；

2) delta 2, on off sequence is:

212(T₂/2)-112(T₁/2)-102(T₃)-112(T₁/2)-212(T₂/2)

3) delta 3, on off sequence is:

212(T₁/2)-202(T₃/2)-102(T₂)-202(T₃/2)-212(T₁/2)

4) delta 4, on off sequence is:

112(T₁/2)-102(T₂/2)-002(T₃)-102(T₂/2)-112(T₁/2)

Big sector S₆：1) delta 1, on off sequence is:

212(T₁/2)-211(T₂/2)-111(T₀)-211(T₂/2)-212(T₁/2)；

2) delta 2, on off sequence is:

212(T₁/2)-211(T₂/2)-201(T₃)-211(T₂/2)-212(T₁/2)

3) delta 3, on off sequence is:

211(T₁/2)-201(T₂/2)-200(T₃)-201(T₂/2)-211(T₁/2)

4) delta 4, on off sequence is:

212(T₁/2)-202(T₃/2)-201(T₂)-202(T₃/2)-212(T₁/2)。

Foregoing table 2 is on off sequence of the three-level three-phase inverter N-type SVPWM control method in regional；Table 3 is three On off sequence of the level three-phase inverter p-type SVPWM control method in regional.

3rd, the SVPWM control method selected by current time is determined

When N-type SVPWM control method is used alone, because midpoint potential is not controlled by, it may occur that serious skew, tool Body is as shown in Figure 5；When p-type SVPWM control method is used alone, because midpoint potential does not add control, serious skew can also occur, It is specific as shown in Figure 6.

In order to ensure the stabilization of midpoint potential, two kinds of control methods are used in combination, following is embodied

Table 5

As shown in table 5, reference voltage vector U_refIn sector S₁And S₄When, neutral balance electric current is Ia.When on DC side The voltage U of lateral capacitance_dc1Higher than the voltage U of lateral capacitance under DC side_dc2When, i.e. U_dc1>U_dc2If, Ia>0, then should select p-type SVPWM is controlled to raise midpoint potential, if Ia<0, then should control to reduce midpoint potential from N-type SVPWM；Work as U_dc1<U_dc2 When, then conversely.Reference voltage vector U_refIn sector S₂And S₅When, neutral balance electric current is Ib.Work as U_dc1>U_dc2If, Ib>0, then Should be from p-type SVPWM controls to raise midpoint potential, if Ib<0, then should be electric to reduce midpoint from N-type SVPWM controls Position；Work as U_dc1<U_dc2, then conversely.Reference voltage vector U_refIn sector S₃And S₆When, neutral balance electric current is Ic.Work as U_dc1> U_dc2If, Ic>0, then should be from p-type SVPWM controls to raise midpoint potential, if Ic<0, then should be controlled from N-type SVPWM To reduce midpoint potential；Work as U_dc1<U_dc2, then conversely.

The corresponding lower output line voltage of NP complementary types SVPWM control method control after the filtering waveform as shown in fig. 7, very Be near the mark sine wave.U_dcDuring=600V, index of modulation M=0.8, with the inductive load 18kVA conditions that power factor (PF) is 0.67 Under, midpoint potential waveform is as shown in figure 8, fluctuation range is：3/600=0.5%.During impact single-phase load, i.e., threephase load is not Neutral-point Potential Fluctuation is larger during balance, but remains in poised state, and after removing shock load, midpoint potential recovers rapidly former First state, it is specific as shown in Figure 9.

For the three-phase inverter that NP complementary types SVPWM control method is controlled, in each small delta-shaped region, at one Inverter working condition switches 4 times in cycle, and accordingly, switching tube is switched 4 times altogether；And inverter is controlled by SVPWM methods When, in each small delta-shaped region, inverter working condition in a cycle switches 6 times, accordingly, power tube switch 6 It is secondary, therefore in the case of identical carrier frequency and the output of identical line voltage, NP complementary type SVPWM control methods are compared SVPWM controls its on-off times to reduce 1/3.

Claims (7)

1. NP complementary type SVPWM control methods of a kind of three-level three-phase inverter, it is characterised in that by by three-level three-phase 24 operation modes of inverter are divided, and by separating three-level three-phase inverter N-type small vector and p-type small vector, N-type is small Vector and 6 big middle vectors of vector 6 constitute N-type control method, and p-type small vector and 6 big middle vectors of vector 6 are constituted P-type SVPWM control method, and two kinds of control methods are contacted as independent control strategy the need for only relying on midpoint potential Come, two kinds of control methods are realized in the interval various combination of different operating and switching control.

2. a kind of NP complementary type SVPWM control methods of three-level three-phase inverter according to claim 1, its feature exists In specifically including following steps：

1) big sector where it is determined by the phase angle of the reference voltage vector of three-phase tri-level inverter, further analysis is with reference to arrow The length and angle relationship of amount obtain residing small delta-shaped region；

2) the small delta-shaped region according to residing for reference vector, selects three Working moulds of corresponding three-phase tri-level inverter State, determines the working time of each operation mode；

3) three switching sequences of operation mode of working time generation according to each operation mode, according to switching sequence control Three operation mode synthesized voltage vectors of system, make the resultant vector of three operation modes follow the circular trace of reference vector to revolve Turn, so as to export the sinusoidal line voltage of three-phase tri-level inverter；

4) by alignment current potential and the sample detecting of each phase current, determine that current time need to use N-type or p-type SVPWM Control method.

3. as claimed in claim 2 a kind of three-level three-phase inverter NP complementary type SVPWM control methods, it is characterised in that It is interval in linear work, N-type SVPWM control method operation mode only have 6 big vectors i.e. (200,220,020,022,002, 202), 6 middle vectors are (210,120,021,012,102,201), 6 N-type small vectors be (100,110,010,011,001, 101), the operation interval can be divided into 6 big sectors, including：Sector S₁, 0 °~60 ° of correspondence；Sector S₂, 60 °~120 ° of correspondence；Fan Area S₃, 120 °~180 ° of correspondence；Sector S₄, 180 °~240 ° of correspondence；Sector S₅, 240 °~300 ° of correspondence；Sector S₆, correspondence 300 °~360 °；6 big sectors again can be 4 small deltas, partitioning standards by the operation interval each vector distal point line Constitute, each big sector dividing mode is consistent, and is centrosymmetric.

P-type SVPWM control method operation mode only has 6 big vectors i.e. (200,220,020,022,002,202), is sweared in 6 Amount is (210,120,021,012,102,201), and 6 p-type small vectors are (211,221,121,122,112,212), the work Interval can be divided into 6 big sectors, including：Including：Sector S₁, 0 °~60 ° of correspondence；Sector S₂, 60 °~120 ° of correspondence；Sector S₃, 120 °~180 ° of correspondence；Sector S₄, 180 °~240 ° of correspondence；Sector S₅, 240 °~300 ° of correspondence；Sector S₆, 300 ° of correspondence~ 360°；6 big sectors can be again 4 small deltas, and partitioning standards are constituted by by each vector distal point line of the operation interval, Each big sector dividing mode is consistent, and is centrosymmetric.

4. NP complementary type SVPWM control methods of a kind of three-level three-phase inverter according to claim 1, it is characterised in that Step 2) in, reference voltage vector is U_ref, θ is U_refWith the actual bit angle setting of α axles in SVPWM, θ₀It is U_refRelative position Angle, inverter DC bus-bar voltage is U_dc, the determination methods of big sector are as follows where reference vector：

1) whenWhen, U_ref∈S₁, U_refThe relative position angle θ of the big sector of place triangle₀=θ；

2) whenWhen, U_ref∈S₂, U_refThe relative position angle of the big sector of place triangle

3) whenWhen, U_ref∈S₃, U_refThe relative position angle of the big sector of place triangle

4) whenWhen, U_ref∈S₄, U_refThe relative position angle θ of the big sector of place triangle₀=θ-π；

5) whenWhen, U_ref∈S₅, U_refThe relative position angle of the big sector of place triangle

6) whenWhen, U_ref∈S₆, U_refThe relative position angle of the big sector of place triangle

Small delta-shaped region can be by relative position angle θ where reference vector₀And the length of reference vector determines jointly：

$U_{ref}{\mathrm{cos\&theta;}}_0+\sqrt{3}{U}_{ref}{\mathrm{sin\&theta;}}_0/3\&le;U_{dc}/3---\left(1\right)$

$U_{ref}{\mathrm{cos\&theta;}}_0-\sqrt{3}{U}_{ref}{\mathrm{sin\&theta;}}_0/3\&GreaterEqual;U_{dc}/3---\left(2\right)$

$U_{ref}{\mathrm{sin\&theta;}}_0\&GreaterEqual;\sqrt{3}{U}_{dc}/6---\left(3\right);$

Judge that rule is as shown in the table, the rule of correspondence is set up in Y expressions in table, and the rule of correspondence is invalid in N expressions ,-table Show unrelated；

5. a kind of NP complementary type SVPWM control methods of three-level three-phase inverter according to claim 4, its feature exists In step 2) in, when selecting used space voltage vector, because N-type or p-type SVPWM control method all only used The small vector of half, therefore only needed according to delta-shaped region where reference voltage vector during selection vector, select three for closing on Voltage vector carrys out Fitted reference voltage vector；

According to the space voltage vector selected, can determine that each space is sweared by the length and relative position angle of reference voltage vector The action time of amount：

1) when reference voltage vector is in small triangle 1, reference voltage vector is by small vector U₁, small vector U₂And zero vector U₀ Synthesis, each vector specific action time is as follows：

$\left\{\begin{array}{c}{T}_1=\sqrt{3}\frac{U_{ref}}{U_{dc}}\left(\sqrt{3}{\mathrm{cos\&theta;}}_0-{\mathrm{sin\&theta;}}_0\right)\&CenterDot;T_s\\ T_2=2\sqrt{3}\frac{U_{ref}}{U_{dc}}{\mathrm{sin\&theta;}}_0\&CenterDot;T_s\\ T_0=T_s-T_1-T_2\end{array}\right.;$

2) when reference voltage vector is in small triangle 2, reference voltage vector is by small vector U₁, small vector U₂And middle vector U₃ Synthesis, each vector specific action time is as follows：

$\left\{\begin{array}{c}{T}_1=\sqrt{3}\frac{U_{ref}}{U_{dc}}\left(\sqrt{3}{\mathrm{cos\&theta;}}_0+{\mathrm{sin\&theta;}}_0\right)\&CenterDot;T_s\\ T_2=\sqrt{3}\frac{U_{ref}}{U_{dc}}\left(-\sqrt{3}{\mathrm{cos\&theta;}}_0+{\mathrm{sin\&theta;}}_0\right)\&CenterDot;T_s\\ T_3=T_s-T_1-T_2\end{array}\right.;$

3) when reference voltage vector is in small triangle 3, reference voltage vector is by small vector U₁, middle vector U₂And big vector U₃ Synthesis, each vector specific action time is as follows：

$\left\{\begin{array}{c}{T}_1=\sqrt{3}\frac{U_{ref}}{U_{dc}}\left(\sqrt{3}{\mathrm{cos\&theta;}}_0+{\mathrm{sin\&theta;}}_0\right)\&CenterDot;T_s\\ T_2=2T_s-\sqrt{3}\frac{U_{ref}}{U_{dc}}\left(\sqrt{3}{\mathrm{cos\&theta;}}_0+3{\mathrm{sin\&theta;}}_0\right)\&CenterDot;T_s\\ T_3=T_s-T_1-T_2\end{array}\right.;$

4) when reference voltage vector is in small triangle 4, reference voltage vector is by small vector U₁, middle vector U₂And big vector U₃ Synthesis, each vector specific action time is as follows：

$\left\{\begin{array}{c}{T}_1=2T_s-\sqrt{3}\frac{U_{ref}}{U_{dc}}\left(\sqrt{3}{\mathrm{cos\&theta;}}_0+3{\mathrm{sin\&theta;}}_0\right)\\ T_2=2\sqrt{3}\frac{U_{ref}}{U_{dc}}{\mathrm{sin\&theta;}}_0\&CenterDot;T_s\\ T_3=T_s-T_1-T_2\end{array}\right..$

6. a kind of NP complementary type SVPWM control methods of three-level three-phase inverter according to claim 2, its feature exists In the step 3) in, it is considered to the continuity and symmetry of on off sequence, the on off sequence of major sectors are defined below：

For N-type SVPWM control method, its switching sequence is:

For p-type SVPWM control method, its switching sequence is:

7. NP complementary type SVPWM control methods of three-level three-phase inverter as claimed in claim 2, it is characterised in that for N Type or p-type SVPWM control method, each all switches over control only with 18 operation modes；NP complementary types SVPWM is controlled Compared to traditional SVPWM control strategies, on-off times reduce 1/3 to mode processed within an output voltage cycle.