CN103633862A - SVPWM frequency conversion device reducing intermediate operation and modulation method thereof - Google Patents

Abstract

The invention relates to a modulation method for SVPWM modulation signals, comprising: establishing a three-phase static coordinate, according to axes of the coordinate, respectively establishing I section, II section, III section, IV section, V section, and VI section in an anticlockwise direction in sequence; and converting corresponding voltage vector time T1 and T2 of desired reference voltage vector in each sector according to projections Va, Vb, and Vc of the desired reference voltage vector on directions of the three-phase static coordinate. The modulation method for SVPWM modulation signals simplifies large number of multiply-divide operations, irrational number operations, trigonometric function operations, and coordinate transformation operations exist in a conventional SVPWM modulation signal realization process, and overcomes disadvantages that the operations take a large amount of CPU computing time and reduce accuracy of operation. The modulation method can be realized just by simple plus and minus operations, cooperating with a small quantity of multiplications, thereby reducing CPU computing time and improving accuracy of operation.

Description

A kind of SVPWM converter plant and modulator approach that reduces intermediate operations

Technical field

The present invention relates to a kind of modulator approach that is suitable for reducing the SVPWM modulation signal of intermediate operations.

Background technology

In recent years, space vector pulse width modulation (SVPWM) technology has obtained application more and more widely in three-phase alternating current conversion.This method can reduce switching loss, improves direct voltage utilance, reduce system harmonics content.

The scheme of the modulator approach of existing SVPWM modulation signal:

The theoretical foundation of SVPWM is the mean value principle of equal effects, in a switch periods by basic voltage vectors is combined, its mean value is equated with given voltage vector.Sometime, voltage vector rotates in certain region, can be obtained by two that form this region adjacent non-zero vector zero vectors various combination in time.Apply several times the action time of two vectors within a sampling period, thereby control the action time of each voltage vector, space vector of voltage is approached by the rotation of circle track, the actual magnetic flux that different on off states by inverter produce removes to approach desirable magnetic flux circle, and by both comparative result, decided the on off state of inverter, thereby form PWM waveform.

Fig. 1 has provided the topological diagram of typical three-phase inverter.Two power tube synchronizations of every phase brachium pontis only have a conducting, have like this 8 kinds of on off states to exist.Fig. 2 has provided the distribution situation of fundamental space vector, and fundamental space vector comprises

the amplitude of six non-zero vectors is

for DC bus-bar voltage).By controlling fundamental space vectorial combination and action time, SVPWM is according to reference voltage vector

be rotated operation.

represent respectively vector

mould, have:

$V_1={\mathrm{<figure-callout\; id="2"\; label="V"\; filenames="HDA0000392453140000011.png,HDA0000392453140000021.png"\; state="\{\{state\}\}">V</figure-callout>}}_2={\mathrm{<figure-callout\; id="3"\; label="V"\; filenames="70675DEST\_PATH\_IMAGE001.png,HDA0000392453140000011.png"\; state="\{\{state\}\}">V</figure-callout>}}_3={\mathrm{<figure-callout\; id="4"\; label="V"\; filenames="70675DEST\_PATH\_IMAGE001.png,HDA0000392453140000011.png"\; state="\{\{state\}\}">V</figure-callout>}}_4={\mathrm{<figure-callout\; id="5"\; label="V"\; filenames="70675DEST\_PATH\_IMAGE001.png,HDA0000392453140000021.png"\; state="\{\{state\}\}">V</figure-callout>}}_5={\mathrm{<figure-callout\; id="6"\; label="V"\; filenames="70675DEST\_PATH\_IMAGE001.png,HDA0000392453140000021.png"\; state="\{\{state\}\}">V</figure-callout>}}_6=\frac{2}{3}{V}_{\mathrm{dc}}.$

In the modulator approach of traditional SVPWM modulation signal, three-phase system model need to be transformed in two-phase rest frame:

$\left[\begin{array}{c}{V}_{\mathrm{alf}}\\ V_{\mathrm{bet}}\end{array}\right]=\frac{2}{3}\&times;\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\&times;\left[\begin{array}{c}{V}_a\\ V_b\\ V_c\end{array}\right]$ (formula 1)

In formula, V _a, V _b, V _cfor space voltage vector

at three phase static coordinate system projection in direction, V _alf, V _betfor reference voltage vector at two phase coordinate systems

projection in direction, V _sfor

mould, have:

V _alf=V _s* cos θ (formula 2)

V _bet=V _s* sin θ (formula 3)

Reference voltage vector

adjacent fundamental space vector is synthetic excessively obtains:

${\stackrel{\&RightArrow;}{V}}_s=\frac{T_k}{T_s}{\stackrel{\&RightArrow;}{V}}_{k+}\frac{T_{k+1}}{T_s}{\stackrel{\&RightArrow;}{V}}_{k+1}$ (formula 4)

In above formula, T _kt _k+1for fundamental space vector

at a sampling period T _sin action time.K is vector place sector number, and azimuth θ can obtain by antitrigonometric function computing in two-phase rest frame.

Judgement reference voltage vector

sector, place, analyzes V _alf, V _betrelation, can obtain following rule:

If V _bet> 0, A=1, otherwise A=0;

If

b=1, otherwise B=0;

If

n=A+2B+4C is differentiated in C=1 otherwise C=0 so sector.

Easily know N=3, N=1, N=5, N=4, N=6, N=2 is corresponding I, II, III, IV, V, VI sector respectively.

Work as reference voltage vector

when I sector, as Fig. 2, fundamental space vector can calculate by through type action time:

$V_{\mathrm{alf}}*T_s=V_1*{\mathrm{<figure-callout\; id="1"\; label="T"\; filenames="70675DEST\_PATH\_IMAGE001.png,HDA0000392453140000011.png"\; state="\{\{state\}\}">T</figure-callout>}}_1+\frac{1}{2}{V}_2*{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="HDA0000392453140000011.png,HDA0000392453140000021.png"\; state="\{\{state\}\}">T</figure-callout>}}_2$

$V_{\mathrm{bes}}*T_s=\frac{\sqrt{3}}{2}{\mathrm{<figure-callout\; id="2"\; label="V"\; filenames="HDA0000392453140000011.png,HDA0000392453140000021.png"\; state="\{\{state\}\}">V</figure-callout>}}_2*{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="HDA0000392453140000011.png,HDA0000392453140000021.png"\; state="\{\{state\}\}">T</figure-callout>}}_2$

Can obtaining of solution:

${\mathrm{<figure-callout\; id="1"\; label="T"\; filenames="70675DEST\_PATH\_IMAGE001.png,HDA0000392453140000011.png"\; state="\{\{state\}\}">T</figure-callout>}}_1=\frac{\frac{3}{2}*V_{\mathrm{alf}}-\frac{\sqrt{3}}{2}*V_{\mathrm{bet}}}{V_{\mathrm{dc}}}*T_s$ (formula 5)

${\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="HDA0000392453140000011.png,HDA0000392453140000021.png"\; state="\{\{state\}\}">T</figure-callout>}}_2=\frac{\sqrt{3}*V_{\mathrm{bet}}}{V_{\mathrm{dc}}}*T_s$ (formula 6)

In like manner can derive the voltage vector action time in other sector, when the synthetic vector of needs is positioned at each different sector, all have computing as above.By solving of each sector basic vector operate time is not difficult to find that they are combinations of some basic times.So provide several basic time variable X, Y, Z.

$X=\frac{\sqrt{3}*V_{\mathrm{bet}}}{V_{\mathrm{dc}}}*T_s$ (formula 7)

$Y=\frac{\frac{\sqrt{3}}{2}*V_{\mathrm{bet}}+\frac{3}{2}*V_{\mathrm{alf}}}{V_{\mathrm{dc}}}*T_s$ (formula 8)

$Z=\frac{\frac{\sqrt{3}}{2}*V_{\mathrm{bet}}+\frac{3}{2}*V_{\mathrm{alf}}}{V_{\mathrm{dc}}}*T_s$ (formula 9)

Conclude when different sector, substantially non-zero space vectors is as shown in the table action time:

Sector

N=3

N=1

N=5

N=4

N=6

N=2

T 1

-Z

Y

X

Z

-Y

-X

T 2

X

Z

-Y

-X

-Z

Y

T ₁, T ₂after assignment, also to judge it, work as T ₁+ T ₂>Ts, gets T ₁=T ₁ts/ (T ₁+ T ₂), T ₂=T ₂ts/ (T ₁+ T ₂).

Finally, adopt the DSP inside of the TMS320LF2407 series of TI company to have hardware to realize, as required, can select the SVPWM of five sections or seven segmentations.

The flow chart of the modulator approach of tradition SVPWM modulation signal as shown in Figure 3.

Traditional as can be seen here, the modulator approach of SVPWM modulation signal need to be carried out a large amount of multiplication and division computings, Coordinate Conversion, trigonometric function operation, irrational number computing etc., and these computings are consuming a large amount of cpu resources in control procedure in real time.

Summary of the invention

The technical problem to be solved in the present invention is to provide a kind of modulator approach that is suitable for reducing the SVPWM modulation signal of intermediate operations, to have solved the modulator approach of traditional SVPWM modulation signal, needs to carry out a large amount of multiplication and division computings, Coordinate Conversion, trigonometric function operation, irrational number computing and related operation to have consumed the technical problem of a large amount of cpu resources in carrying out real-time control procedure.

The modulator approach that the invention provides a kind of SVPWM modulation signal, comprising:

1. set up a three phase static coordinate system according to its axis, from

direction respectively is I, II, III, IV, V, VI sector counterclockwise;

2. required reference voltage vector

relevant voltage vector T action time in each sector ₁, T ₂:

Wherein, N=3, N=1, N=5, N=4, N=6, N=2 is corresponding I, II, III, IV, V, VI sector respectively; Ts is a sampling period, and the first intermediate variable is established T _t1=(V _aten 2V _b)/V _dc, the second intermediate variable is established T _t2=(V _a-V _b)/V _dc, the 3rd intermediate variable is established T _t3=(2V _a+ V _b)/V _dc, V _a, V _b, V _cfor required reference voltage vector

at three phase static coordinate system

projection in direction, V _dcfor DC bus-bar voltage.

Further, the modulator approach of described SVPWM modulation signal also comprises: judge required reference voltage vector

step in respective sectors, this step comprises:

If sector discriminant:, N=A+2B+4C.

If the first intermediate variable T _t1> 0, A=1, otherwise A=0;

If the second intermediate variable T _t2> 0, B=1, otherwise B=0;

If the 3rd intermediate variable T _t3< 0, C=1, otherwise C=0;

According to the judgement of each intermediate variable, to determine the value of corresponding A, B, C, sector discriminant is to obtain required reference voltage vector described in substitution

sector, place, i.e. N=3, N=1, N=5, N=4, N=6, N=2 is corresponding I, II, III, IV, V, VI sector respectively.

The present invention also provides a kind of SVPWM converter plant, comprise: three-phase inverter, this three-phase inverter is by a master control module controls, the DC side of this three-phase inverter, AC are respectively equipped with direct current, alternating voltage current detection circuit, and described direct current, alternating voltage current detection circuit are connected with described main control module;

The method that this main control module produces SVPWM modulation signal comprises:

Set up a three phase static coordinate system according to its axis, from

direction respectively is I, II, III, IV, V, VI sector counterclockwise;

Required reference voltage vector

relevant voltage vector T action time in each sector ₁, T ₂:

Wherein, N=3, N=1, N=5, N=4, N=6, N=2 is corresponding I, II, III, IV, V, VI sector respectively; Ts is a sampling period, and the first intermediate variable is established T _t1=(V _a+ 2V _b)/V _dc, the second intermediate variable is established T _t2=(V _a-V _b)/V _dc, the 3rd intermediate variable is established T _t3=(2V _a+ V _b)/V _dc, V _a, V _b, V _cfor required reference voltage vector at three phase static coordinate system

projection in direction, V _dcfor DC bus-bar voltage.

T ₁, T ₂after assignment, also to judge it, work as T ₁+ T ₂>Ts, gets T ₁=T ₁ts/ (T ₁+ T ₂), T ₂=T ₂ts/ (T ₁+ T ₂).

Finally, adopt the DSP inside of the TMS320LF2407 series of TI company to have hardware to realize, as required, can select the SVPWM of five sections or seven segmentations.

Further, described SVPWM converter plant, the method that described main control module produces SVPWM modulation signal also comprises:

Judge required reference voltage vector

step in respective sectors, this step comprises:

If sector discriminant: N=A+2B+4C.

If the first intermediate variable T _t1> 0, A=1, otherwise A=0;

If the second intermediate variable T _t2> 0, B=1, otherwise B=0;

If the 3rd intermediate variable T _t3< 0, C=1, otherwise C=0;

According to the judgement of each intermediate variable, to determine the value of corresponding A, B, C, sector discriminant is to obtain required reference voltage vector described in substitution

sector, place, i.e. N=3, N=1, N=5, N=4, N=6, N=2 is corresponding I, II, III, IV, V, VI sector respectively.

Compared with prior art, tool of the present invention has the following advantages: the modulator approach of (1) SVPWM modulation signal of the present invention has been simplified a large amount of multiplication and division computings, irrational number computing, trigonometric function, the Coordinate Conversion computing existing in the implementation procedure of modulator approach of traditional SVPWM modulation signal, and has overcome the defect that these calculating take a large amount of CPU computing time, reduce computational accuracy.The modulator approach of SVPWM modulation signal of the present invention, only needs by simple plus and minus calculation, and coordinates a small amount of multiplying to realize, and greatly reduces the computing time of CPU, has improved the precision of calculating.(2) SVPWM converter plant of the present invention, described main control module is without the multiplication and division computing by loaded down with trivial details, irrational number computing, trigonometric function, Coordinate Conversion computing, improved main control module operation efficiency, saved computing time.

Accompanying drawing explanation

For content of the present invention is more likely to be clearly understood, below the specific embodiment by reference to the accompanying drawings of basis, the present invention is further detailed explanation, wherein

The topological diagram of Fig. 1 three-phase inverter;

Fig. 2 space vector of voltage figure;

The modulator approach flow chart of Fig. 3 tradition SVPWM modulation signal;

The modulator approach flow chart of Fig. 4 SVPWM modulation signal of the present invention.

Embodiment

Below in conjunction with drawings and Examples, the present invention is described in detail:

Embodiment 1

The modulator approach of seeing a kind of SVPWM modulation signal of Fig. 2, Fig. 4, comprising:

1. set up a three phase static coordinate system according to its axis, from direction respectively is I, II, III, IV, V, VI sector counterclockwise;

2. required reference voltage vector relevant voltage vector T action time in each sector ₁, T ₂:

Wherein, N=3, N=1, N=5, N=4, N=6, N=2 is corresponding I, II, III, IV, V, VI sector respectively; Ts is a sampling period, and the first intermediate variable is established T _t1=(V _a+ 2V _b)/V _dc, the second intermediate variable is established T _t2=(V _a-V _b)/V _dcten thousand the 3rd intermediate variables are established T _t3=(2V _a+ V _b)/V _dc, V _a, V _b, V _cfor required reference voltage vector at three phase static coordinate system projection in direction, V _dcfor DC bus-bar voltage.

Wherein, V in calculating _a, V _b, V _cwithout using, saved calculation procedure, as long as V _a, V _b, V _ctwo amounts just can complete relevant voltage vector T action time ₁, T ₂calculating.

The modulator approach of described SVPWM modulation signal, also comprises: judge required reference voltage vector V _sstep in respective sectors, this step comprises:

If sector discriminant: N=A+2B+4C.

If the first intermediate variable T _t1> 0, A=1, otherwise A=0;

If the second intermediate variable T _t2> 0, B=1, otherwise B=0;

If the 3rd intermediate variable T _t3< 0, C=1, otherwise C=0;

According to the judgement of each intermediate variable, to determine the value of corresponding A, B, C, sector discriminant is to obtain required reference voltage vector described in substitution

sector, place, i.e. N=3, N=1, N=5, N=4, N=6, N=2 is corresponding I, II, III, IV, V, VI sector respectively.

The derivation of embodiment 1 is as follows:

Required reference voltage vector

projection on three phase static coordinate system is respectively V _a, V _b, V _c, have

$V_a+V_b+V_c=\mathrm{Vs}*\cos \mathrm{\&theta;}+\mathrm{Vs}*\cos (\mathrm{\&theta;}-\frac{2}{3}\mathrm{\&pi;})+\mathrm{Vs}*\cos (\mathrm{\&theta;}+\frac{2}{3}\mathrm{\&pi;})=0$ Formula (10)

By formula (1) and formula (10), obtained

$\left(\begin{array}{c}{V}_{\mathrm{alf}}\\ V_{\mathrm{bet}}\end{array}\right)=\left(\begin{array}{cc}1& 0\\ \frac{\sqrt{3}}{3}& \frac{2}{3}\sqrt{3}\end{array}\right)\&times;\left(\begin{array}{c}{V}_a\\ V_b\end{array}\right)$ Formula (11)

$V_{\mathrm{alf}}=1*V_a+0*V_b$

$V_{\mathrm{bet}}=\frac{\sqrt{3}}{3}*V_a+\frac{2}{3}\sqrt{3}*V_b$ Formula (12)

Judge required reference voltage vector

sector, place, analyzes V _alf, V _betrelation, by V _alf, V _betuse respectively V _a, V _bbring the described judgement reference voltage vector representing in background technology into

sector, place, analyzes V _alf, V _betrelation, be about to the inequality that formula (12) substitution is judged, obtain following rule:

If V _a+ 2V _b0 A=1 of > otherwise A=0;

If V _a-V _b0 B=1 of >, otherwise B=0;

If 2V _a+ V _b0 C=1 of <, otherwise C=0;

So sector N=A+2B+4C.

When required reference voltage vector

when I sector, as Fig. 2, fundamental space vector can calculate by through type action time:

${\mathrm{<figure-callout\; id="1"\; label="T"\; filenames="70675DEST\_PATH\_IMAGE001.png,HDA0000392453140000011.png"\; state="\{\{state\}\}">T</figure-callout>}}_1=\frac{\frac{3}{2}*V_{\mathrm{alf}}-\frac{\sqrt{3}}{2}*V_{\mathrm{bet}}}{V_{\mathrm{dc}}}*T_s=\frac{V_a-V_b}{V_{\mathrm{dc}}}*T_s$ (formula 13)

${\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="HDA0000392453140000011.png,HDA0000392453140000021.png"\; state="\{\{state\}\}">T</figure-callout>}}_2=\frac{\sqrt{3}*V_{\mathrm{bet}}}{V_{\mathrm{dc}}}*T_s=\frac{2V_a-V_b}{V_{\mathrm{dc}}}*T_s$

When required reference voltage vector

when II sector

${\mathrm{<figure-callout\; id="1"\; label="T"\; filenames="70675DEST\_PATH\_IMAGE001.png,HDA0000392453140000011.png"\; state="\{\{state\}\}">T</figure-callout>}}_1=\frac{\frac{\sqrt{3}}{2}*V_{\mathrm{bet}}+\frac{3}{2}*V_{\mathrm{alf}}}{V_{\mathrm{dc}}}*T_s=\frac{{2V}_a+V_b}{V_{\mathrm{dc}}}*T_s$

${\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="HDA0000392453140000011.png,HDA0000392453140000021.png"\; state="\{\{state\}\}">T</figure-callout>}}_2=\frac{\frac{\sqrt{3}}{2}*V_{\mathrm{bet}}-\frac{3}{2}*V_{\mathrm{alf}}}{V_{\mathrm{dc}}}*T_s=\frac{V_a-V_b}{V_{\mathrm{dc}}}*T_s$

When required reference voltage vector

when V sector

${\mathrm{<figure-callout\; id="1"\; label="T"\; filenames="70675DEST\_PATH\_IMAGE001.png,HDA0000392453140000011.png"\; state="\{\{state\}\}">T</figure-callout>}}_1=-\frac{\frac{\sqrt{3}}{2}*V_{\mathrm{bet}}+\frac{3}{2}*V_{\mathrm{alf}}}{V_{\mathrm{dc}}}*T_s=-\frac{{2V}_a+V_b}{V_{\mathrm{dc}}}*T_s$

${\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="HDA0000392453140000011.png,HDA0000392453140000021.png"\; state="\{\{state\}\}">T</figure-callout>}}_2=-\frac{\frac{\sqrt{3}}{2}*V_{\mathrm{bet}}-\frac{3}{2}*V_{\mathrm{alf}}}{V_{\mathrm{dc}}}*T_s=\frac{V_a-V_b}{V_{\mathrm{dc}}}*T_s$

Make T _t1=(V _a+ 2V _b)/V _dc, T _t2=(V _a-V _b)/V _dc,

T _t3=(2V _a+ V _b)/V _dc, V wherein _dcfor DC bus-bar voltage.

Therefore known by computing

If the first intermediate variable T _t1> 0, A=1, otherwise A=0;

If the second intermediate variable T _t2> 0, B=1, otherwise B=0;

If the 3rd intermediate variable T _t3< 0, C=1, otherwise C=0;

According to the judgement of each intermediate variable, to determine the value of corresponding A, B, C, sector discriminant N=A+2B+4C. is to obtain required reference voltage vector described in substitution

sector, place, i.e. N=3, N=1, N=5, N=4, N=6, N=2 is corresponding I, II, III, IV, V, VI sector respectively.

In like manner can derive the voltage vector action time in other sector, conclusion is as shown in the table action time:

Embodiment 2

A kind of SVPWM converter plant on embodiment 1 basis, comprise: three-phase inverter, this three-phase inverter is by a master control module controls, the DC side of this three-phase inverter, AC are respectively equipped with direct current, alternating voltage current detection circuit, and described direct current, alternating voltage current detection circuit are connected with described main control module;

The method that this main control module produces SVPWM modulation signal comprises:

Set up a three phase static coordinate system according to its axis, from

direction respectively is I, II, III, IV, V, VI sector counterclockwise;

Required reference voltage vector

relevant voltage vector T action time in each sector ₁, T ₂:

Wherein, N=3, N=1, N=5, N=4, N=6, N=2 is corresponding I, II, III, IV, V, VI sector respectively; Ts is a sampling period, and the first intermediate variable is established T _t1=(V _a+ 2V _b)/V _dc, the second intermediate variable is established T _t2=(V _a-V _b)/V _dc, the 3rd intermediate variable is established T _t3=(2V _a+ V _b)/V _dc, V _a, V _b, V _cfor required reference voltage vector

at three phase static coordinate system projection in direction, V _dcfor DC bus-bar voltage.

Wherein, V in calculating _a, V _b, V _cwithout using, saved calculation procedure, as long as V _a, V _b, V _ctwo amounts just can complete relevant voltage vector T action time ₁, T ₂calculating.

T ₁, T ₂after assignment, also to judge it, work as T ₁+ T ₂>Ts, gets T ₁=T ₁ts/ (T ₁+ T ₂), T ₂=T ₂ts/ (T ₁+ T ₂).

Finally, adopt the DSP inside of the TMS320LF2407 series of TI company to have hardware to realize, as required, can select the SVPWM of five sections or seven segmentations.

Wherein, V in calculating _a, V _b, V _cwithout using, saved calculation procedure, as long as V _a, V _b, V _ctwo amounts just can complete relevant voltage vector T action time ₁, T ₂calculating.

The method that described main control module produces SVPWM modulation signal also comprises:

Judge required reference voltage vector

step in respective sectors, this step comprises:

If sector discriminant: N=A+2B+4C.

If the first intermediate variable T _t1> 0, A=1, otherwise A=0;

If the second intermediate variable T _t2> 0, B=1, otherwise B=0;

If the 3rd intermediate variable T _t3< 0, C=1, otherwise C=0;

According to the judgement of each intermediate variable, to determine the value of corresponding A, B, C, sector discriminant is to obtain required reference voltage vector described in substitution

sector, place, i.e. N=3, N=1, N=5, N=4, N=6, N=2 is corresponding I, II, III, IV, V, VI sector respectively.

Obviously, above-described embodiment is only for example of the present invention is clearly described, and is not the restriction to embodiments of the present invention.For those of ordinary skill in the field, can also make other changes in different forms on the basis of the above description.Here exhaustive without also giving all execution modes.And these belong to apparent variation that spirit of the present invention extended out or change still among protection scope of the present invention.

Claims (4)

1. a modulator approach for SVPWM modulation signal, is characterized in that comprising:

1. set up a three phase static coordinate system according to its axis, from

direction respectively is I, II, III, IV, V, VI sector counterclockwise;

2. required reference voltage vector

relevant voltage vector T action time in each sector ₁, T ₂:

Wherein, N=3, N=1, N=5, N=4, N=6, N=2 is corresponding I, II, III, IV, V, VI sector respectively; Ts is a sampling period, and the first intermediate variable is established Tt ₁=(V _a+ 2V _b)/V _dc, the second intermediate variable is established T _t2=(V _a-V _b)/V _dc, the 3rd intermediate variable is established T _t3=(2V _a+ V _b)/V _dc, V _a, V _b, V _cfor required reference voltage vector at three phase static coordinate system

projection in direction, V _dcfor DC bus-bar voltage.

2. the modulator approach of SVPWM modulation signal according to claim 1, characterized by further comprising: judge required reference voltage vector

step in respective sectors, this step

Comprise:

If sector discriminant: N=A+2B+4C.

If the first intermediate variable T _t1> 0, A=1, otherwise A=0;

If the second intermediate variable T _t2> 0, B=1, otherwise B=0;

If the 3rd intermediate variable T _t3< 0, C=1, otherwise C=0;

According to the judgement of each intermediate variable, to determine the value of corresponding A, B, C, sector discriminant is to obtain required reference voltage vector described in substitution

sector, place, i.e. N=3, N=1, N=5, N=4, N=6, N=2 is corresponding I, II, III, IV, V, VI sector respectively.

3. the method for work of a SVPWM converter plant, it is characterized in that this SVPWM converter plant comprises, three-phase inverter, this three-phase inverter is by a master control module controls, the DC side of this three-phase inverter, AC are respectively equipped with direct current, alternating voltage current detection circuit, and described direct current, alternating voltage current detection circuit are connected with described main control module;

The method that this main control module produces SVPWM modulation signal comprises:

Set up a three phase static coordinate system according to its axis, from direction respectively is I, II, III, IV, V, VI sector counterclockwise;

Required reference voltage vector

relevant voltage vector T action time in each sector ₁, T ₂:

Wherein, N=3, N=1, N=5, N=4, N=6, N=2 is corresponding I, II, III, IV, V, VI sector respectively; Ts is a sampling period, and the first intermediate variable is established T _t1=(V _a+ 2V _b)/V _dc, the second intermediate variable is established T _t2=(V _a-V _b)/V _dc, the 3rd intermediate variable is established T _t3=(2V _a+ V _b)/V _dc, V _a, V _b, V _cfor required reference voltage vector

at three phase static coordinate system projection in direction, V _dcfor DC bus-bar voltage.

4. the method for work of SVPWM converter plant according to claim 3, is characterized in that, the method that described main control module produces SVPWM modulation signal also comprises:

Judge required reference voltage vector step in respective sectors, this step comprises:

If sector discriminant: N=A+2B+4C.

If the first intermediate variable T _t1> 0, A=1, otherwise A=0;

If the second intermediate variable T _t2> 0, B=1, otherwise B=0;

If the 3rd intermediate variable T _t3< 0, C=1, otherwise C=0;

According to the judgement of each intermediate variable, to determine the value of corresponding A, B, C, sector discriminant is to obtain required reference voltage vector described in substitution

sector, place, i.e. N=3, N=1, N=5, N=4, N=6, N=2 is corresponding I, II, III, IV, V, VI sector respectively.

Images