CN113241983A - Dead zone compensation method and system for three-phase voltage source inverter - Google Patents

Abstract

The invention discloses a dead-zone compensation method and a system of a three-phase voltage source inverter, which are used for compensating dead zones according to a given voltage u_α、u_βDetermining a reference voltage vector

The SVPWM sector is located; obtaining a reference voltage vector

Action time t of two non-zero basic voltage vectors of the located sector in one PWM period₁、t₂(ii) a According to t₁、t₂And inverter dead time t_DFor the action time t₁、t₂Compensation is carried out, and the action time after compensation is t_1n、t_2n(ii) a According to the compensated action time t_1n、t_2nCalculating to generate new six paths of PWM signals, and outputting the new six paths of PWM signals to the inverter so as to control the on-off of six switching tubes of the inverter; the dead zone compensation method of the three-phase voltage source inverter has the advantages of high compensation precision, good compensation effect, high reliability, no need of any additional hardware, low economic cost and high transportability.

Description

Dead zone compensation method and system for three-phase voltage source inverter

Technical Field

The invention belongs to the technical field of voltage source inverters, and particularly relates to a dead zone compensation method and system for a three-phase voltage source inverter.

Background

When a three-phase voltage source inverter is modulated by SVPWM (Space Vector Pulse Width Modulation) and is operated with a pure resistance or a resistance-inductance load, in order to improve the operation reliability of the three-phase voltage source inverter and avoid the direct-current power supply short circuit caused by the simultaneous conduction of two switching tubes on the same bridge arm of the three-phase voltage source inverter, dead zone time is necessarily added into driving signals of the upper switching tube and the lower switching tube of the same bridge arm, and the dead zone time is added to cause the distortion of the output voltage waveform of the inverter, the increase of harmonic content and other dead zone effects, so that the performance of a control system is seriously influenced.

Current research on dead band compensation has shifted from relatively costly hardware compensation to low cost, high portability software compensation. Because the dead time causes the output deviation voltage of the inverter to be related to the polarity of the phase current, the traditional dead time compensation method mostly determines the voltage amount required to be compensated according to the polarity of the phase current, and the dead time effect is more obvious in low frequency and light load, the amplitude of the phase current is very small, the detection of the polarity of the current is difficult, the detection precision is low and unreliable, the error compensation is easily caused, and the influence of the dead time effect can be further amplified. For the dead zone compensation method which takes improvement of the judgment precision of the current polarity and bypassing of the current polarity detection as starting points, not only complex analysis and calculation are needed, but also the amplitude of the output voltage of the inverter after compensation is not improved well, the compensation effect of the dead zone is measured only by reducing the total harmonic distortion of the phase current, and the improvement condition of the voltage waveform distortion and the total harmonic distortion after the dead zone compensation is not clearly illustrated.

Disclosure of Invention

The dead zone compensation method of the three-phase voltage source inverter provided by the invention has the advantages of good compensation effect, high reliability, high transportability, no need of any additional hardware equipment and low economic cost.

In order to solve the technical problems, the invention adopts the following technical scheme:

a dead-time compensation method of a three-phase voltage source inverter comprises the following steps:

(1) according to a given voltage u_α、u_βDetermining a reference voltage vector

The SVPWM sector is located;

wherein u is_α、u_βThe voltage amplitudes of an alpha axis and a beta axis under the two-phase static coordinate system are respectively; reference voltage vector

Is u under a two-phase stationary coordinate system_α、u_βThe resultant vector of (a);

(2) obtaining a reference voltage vector

Action time t of two non-zero basic voltage vectors of the SVPWM sector in one PWM period₁、t₂；

(3) According to the duration of action t₁、t₂And inverter dead time t_DThe compensated action time t is calculated by the following compensation calculation formula_1n、t_2n：

If the condition (i) is satisfied: t is t₁＞t_DAnd t is 2₂＞t_DA/2, then

If the condition (II) is met: condition is not satisfied, and t₁≥t₂Then, then

If the condition (c) is satisfied: the condition is not satisfied, and t₁＜t₂Then, then

If the condition (iv) is satisfied: if the first condition, the second condition and the third condition are not satisfied, the

(4) According to the compensated action time t_1n、t_2nAnd calculating to generate new six paths of PWM signals, and outputting the new six paths of PWM signals to the three-phase voltage source inverter.

Further, the step (1) specifically comprises:

(11) the variable u is calculated according to the following formula_ref1、u_ref2、u_ref3A value of (d);

(12) value of calculation variable A, B, C, N:

if u_ref1If the value is more than 0, A is equal to 1, otherwise, A is equal to 0;

if u_ref2If the value is more than 0, B is equal to 1, otherwise, B is equal to 0;

if u_ref3If the value is more than 0, C is 1, otherwise, C is 0;

N＝4C+2B+A；

(13) according to the corresponding relation between N and the sector, the method can obtain

The sector in which it is located.

Still further, the step (2) specifically includes:

(21) the value of variable X, Y, Z is calculated according to the following equation:

wherein u is_dcThe value of the direct current bus voltage is T, and T is the time of one PWM period;

(22) determining action time t according to corresponding relation between sectors and X, Y, Z and action time₁、t₂。

Further, the establishment of the compensation calculation formula comprises the following steps:

(31) within one PWM period, according to t₁、t₂And t_DThe magnitude relationship of the three classifies dead zone states into four categories:

dead zone state 1: t is t₁>t_DAnd t is₂>t_D；

Dead zone state 2: t is t₁>t_DAnd t is₂≤t_DOr t₁≤t_DAnd t is₂>t_D；

Dead zone state 3: t is t₁≤t_DAnd t is₂≤t_DAnd t is₁+t₂>t_D；

Dead zone state 4: t is t₁+t₂≤t_D；

(32) For the dead zone state 1: when t is₁>t_DAnd t is₂>t_DWhen t is_1n＝t₁+t_D/2，t_2n＝t₂+t_D/2；

(33) For the dead zone state 2:

when t is₁>t_DAnd t is₂≤t_DWhen t is₂>t_D2, then t_1n＝t₁+t_D/2，t_2n＝t₂+t_D/2；

If t₂≤t_D2, then t_1n＝t₁+t_D–t₂，t_2n＝2t₂；

When t is₁≤t_DAnd t is₂>t_DWhen t is₁>t_D2, then t_1n＝t₁+t_D/2，t_2n＝t₂+t_D/2；

If t₁≤t_D2, then t_1n＝2t₁，t_2n＝t₂+t_D–t₁；

(34) For dead zone state 3, when t₁≤t_DAnd t is₂≤t_DAnd t is₁+t₂>t_DThe method comprises the following steps:

if t₂≤t_DAnd t is 2₁>t₂Then t is_1n＝t₁+t_D–t₂，t_2n＝2t₂；

If t₁≤t_DAnd t is 2₂>t₁Then t is_1n＝2t₁，t_2n＝t₂+t_D–t₁；

If t₁>t_DAnd t is 2₂>t_D2, then t_1n＝t₁+t_D/2，t_2n＝t₂+t_D/2；

(35) For the dead zone state 4, when t₁+t₂≤t_DThe method comprises the following steps:

if t₂≤t_DAnd t is 2₁>t₂Then t is_1n＝t₁+t_D–t₂，t_2n＝2t₂；

If t₁≤t_DAnd t is 2₂>t₁Then t is_1n＝2t₁，t_2n＝t₂+t_D–t₁；

(36) And (32) to (35) are integrated to obtain the compensation calculation formula.

A three-phase voltage source inverter dead-time compensation system comprising:

a sector judging module for judging the sector according to the given voltage u_α、u_βDetermining a reference voltage vector

The SVPWM sector is located; wherein u is_α、u_βThe voltage amplitudes of an alpha axis and a beta axis under the two-phase static coordinate system are respectively; reference voltage vector

Is u under a two-phase stationary coordinate system_α、u_βThe resultant vector of (a);

an action time acquisition module for acquiring a reference voltage vector

Action time t of two non-zero basic voltage vectors of the SVPWM sector in one PWM period₁、t₂；

A compensation calculation module for calculating the compensation according to the action time t₁、t₂And inverter dead time t_DThe compensated action time t is calculated by the following compensation calculation formula_1n、t_2n：

If the condition (i) is satisfied: t is t₁＞t_DAnd t is 2₂＞t_DA/2, then

If the condition (II) is met: condition is not satisfied, and t₁≥t₂Then, then

If the condition (c) is satisfied: the condition is not satisfied, and t₁＜t₂Then, then

If the condition (iv) is satisfied: if the first condition, the second condition and the third condition are not satisfied, the

A PWM signal generation module for generating a PWM signal according to the compensated action time t_1n、t_2nCalculating to generate new six paths of PWM signals, and outputting the new six paths of PWM signals to the three-phase voltage source inverter;

and the three-phase voltage source inverter is used for receiving the PWM signal output by the PWM signal generation module and outputting three-phase voltage.

Further, the sector determining module is specifically configured to:

(11) the variable u is calculated according to the following formula_ref1、u_ref2、u_ref3A value of (d);

(12) value of calculation variable A, B, C, N:

if u_ref1If the value is more than 0, A is equal to 1, otherwise, A is equal to 0;

if u_ref2If the value is more than 0, B is equal to 1, otherwise, B is equal to 0;

if u_ref3If the value is more than 0, C is 1, otherwise, C is 0;

N＝4C+2B+A；

(13) according to the corresponding relation between N and the sector, the method can obtain

The sector in which it is located.

Still further, the action time acquiring module is specifically configured to:

(21) the value of variable X, Y, Z is calculated according to the following equation:

wherein u is_dcThe value of the direct current bus voltage is T, and T is the time of one PWM period;

(22) determining action time t according to corresponding relation between sectors and X, Y, Z and action time₁、t₂。

Further, the compensation calculation module includes a compensation formula establishing unit, and the compensation formula establishing unit is specifically configured to:

(31) within one PWM period, according to t₁、t₂And t_DThe size relationship of the three divides the dead zone state into fourThe category:

dead zone state 1: t is t₁>t_DAnd t is₂>t_D；

Dead zone state 2: t is t₁>t_DAnd t is₂≤t_DOr t₁≤t_DAnd t is₂>t_D；

Dead zone state 3: t is t₁≤t_DAnd t is₂≤t_DAnd t is₁+t₂>t_D；

Dead zone state 4: t is t₁+t₂≤t_D；

(32) For the dead zone state 1: when t is₁>t_DAnd t is₂>t_DWhen t is_1n＝t₁+t_D/2，t_2n＝t₂+t_D/2；

(33) For the dead zone state 2:

when t is₁>t_DAnd t is₂≤t_DWhen t is₂>t_D2, then t_1n＝t₁+t_D/2，t_2n＝t₂+t_D/2；

If t₂≤t_D2, then t_1n＝t₁+t_D–t₂，t_2n＝2t₂；

When t is₁≤t_DAnd t is₂>t_DWhen t is₁>t_D2, then t_1n＝t₁+t_D/2，t_2n＝t₂+t_D/2；

If t₁≤t_D2, then t_1n＝2t₁，t_2n＝t₂+t_D–t₁；

(34) For dead zone state 3, when t₁≤t_DAnd t is₂≤t_DAnd t is₁+t₂>t_DThe method comprises the following steps:

if t₂≤t_DAnd t is 2₁>t₂Then t is_1n＝t₁+t_D–t₂，t_2n＝2t₂；

If t₁≤t_DAnd t is 2₂>t₁Then t is_1n＝2t₁，t_2n＝t₂+t_D–t₁；

If t₁>t_DAnd t is 2₂>t_D2, then t_1n＝t₁+t_D/2，t_2n＝t₂+t_D/2；

(35) For the dead zone state 4, when t₁+t₂≤t_DThe method comprises the following steps:

if t₂≤t_DAnd t is 2₁>t₂Then t is_1n＝t₁+t_D–t₂，t_2n＝2t₂；

If t₁≤t_DAnd t is 2₂>t₁Then t is_1n＝2t₁，t_2n＝t₂+t_D–t₁；

(36) And (32) to (35) are integrated to obtain the compensation calculation formula.

Compared with the prior art, the invention has the advantages and positive effects that: the dead zone compensation method and system of the three-phase voltage source inverter of the invention are realized according to the given voltage u_α、u_βDetermining a reference voltage vector

The SVPWM sector is located; to obtain

Action time t of two non-zero basic voltage vectors of the located sector in one PWM period₁、t₂(ii) a According to t₁、t₂And inverter dead time t_DFor the action time t₁、t₂Compensation is carried out, and the action time after compensation is t_1n、t_2n(ii) a According to the compensated action time t_1n、t_2nCalculating to generate new six-path PWM signals, and outputting the signals to three-phase powerThe voltage source inverter controls the on-off of six switching tubes of the inverter; the dead zone compensation method of the three-phase voltage source inverter has the advantages of high compensation precision, good compensation effect, high reliability, no need of any additional hardware, low economic cost and high transportability.

Other features and advantages of the present invention will become more apparent from the following detailed description of the invention when taken in conjunction with the accompanying drawings.

Drawings

FIG. 1 is a schematic diagram of a dead-time compensation method for a three-phase voltage source inverter according to the present invention;

FIG. 2 is a circuit topology diagram of a three-phase voltage source inverter;

FIG. 3 is a sector diagram of SVPWM;

FIG. 4 is the dead band state 1 (t)₁>t_DAnd t is₂>t_D) Waveforms in the next complete PWM period and voltage vector action duration and amplitude diagrams corresponding to the switching states of the six switching tubes;

FIG. 5 shows the dead zone state 2 (t)₁>t_DAnd t is₂≤t_D) Waveforms in the next complete PWM period and voltage vector action duration and amplitude diagrams corresponding to the switching states of the six switching tubes;

FIG. 6 shows the dead zone state 3 (t)₁≤t_DAnd t is₂≤t_DAnd t is₁+t₂>t_D) Waveforms in the next complete PWM period and voltage vector action duration and amplitude diagrams corresponding to the switching states of the six switching tubes;

FIG. 7 shows the dead zone state 4 (t)₁+t₂≤t_D) Waveforms in the next complete PWM period and voltage vector action duration and amplitude diagrams corresponding to the switching states of the six switching tubes;

FIG. 8 is a flow chart of one embodiment of a method for dead-time compensation of a three-phase voltage source inverter as contemplated by the present invention;

fig. 9 is a block diagram of the dead-time compensation system of the three-phase voltage source inverter according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings and examples.

The invention provides a dead zone compensation method and a system of a three-phase voltage source inverter aiming at SVPWM voltage vector integrity, which do not need additional hardware equipment, judge the polarity of phase current and detect any parameter, and can compensate the inverter output voltage distortion and harmonic content increase caused by the dead zone by simple analysis and volt-second balance calculation. The method can be used for occasions such as independent power supply of a new energy power generation inverter in remote mountainous areas. The dead-time compensation method and system for the three-phase voltage source inverter will be described in detail below.

First embodiment, the dead-zone compensation method for a three-phase voltage source inverter of the present embodiment specifically includes the following steps, as shown in fig. 1 and fig. 8.

Step S1: according to a given voltage u_α、u_βDetermining a reference voltage vector

The SVPWM sector is located; wherein u is_α、u_βThe voltage amplitudes of an alpha axis and a beta axis under the two-phase static coordinate system are respectively; reference voltage vector

Is u under a two-phase stationary coordinate system_α、u_βThe resultant vector of (2).

The circuit topology diagram of the three-phase voltage source inverter is shown in fig. 2, when dead zones are not considered, in a complete PWM period, 8 conduction states of 6 switching tubes are available, and the switching tube S_xThe on-off states of (x ═ 1,2,3,4,5,6) are respectively represented by 1 and 0, and then 8 conducting states are represented by three switching tubes S of the upper arm₁、S₃、S₅Denoted 001, 010, 011, 100, 101, 110, 111, 000.

And considering the conduction delay of the switching tube caused by the dead zone, and the reconstructed voltage vector is different from that in the absence of the dead zone. In a complete PWM cycleIn the inner, there are 27 independent conduction states of 6 switch tubes, and these 27 states can be used by formula N_s＝2⁰·S₁+2¹·S₂+2²·S₃+2³·S₄+2⁴·S₅+2⁵·S₆Numbering is carried out, and different N can be obtained by the permutation and combination of the independent working states of 6 switching tubes_sNumber, its number value [ N_s]And voltage vector

The correspondence in SVPWM sectors is shown in fig. 3, and the remaining 13 voltage vectors are all zero vectors generated by the dead zone effect.

The 27 switching states and N are determined by the 6 switching tube positions in FIG. 2_sThe serial numbers are respectively as follows: 010101(42), 000101(40), 010001(34), 010100(10), 000001(32), 000100(8), 010000(2), 000000(0), 101010(21), 100101(41), 100001(33), 100100(9), 100000(1), 101001(37), 101000(5), 011001(38), 001001(36), 011000(6), 001000(4), 011010(22), 001010(20), 010110(26), 010010(18), 000110(24), 000010(16), 100110(25), 100010 (17).

Two non-zero fundamental voltage vectors of sector I are

Two non-zero fundamental voltage vectors of sector II are

Two non-zero fundamental voltage vectors of sector III are

Two non-zero fundamental voltage vectors of sector IV are

Two non-zero fundamental voltage vectors for sector VMeasured as

Two non-zero fundamental voltage vectors of sector VI are

In the present embodiment, according to a given voltage u_α、u_βDetermining a reference voltage vector

The SVPWM sector comprises the following steps:

s11: defining three variables u_ref1、u_ref2、u_ref3The variable u is calculated according to the following formula_ref1、u_ref2、u_ref3The value of (c).

S12: then 4 variables A, B, C, N are defined and the value of variable A, B, C, N is calculated.

If u_ref1If the value is more than 0, A is equal to 1, otherwise, A is equal to 0;

if u_ref2If the value is more than 0, B is equal to 1, otherwise, B is equal to 0;

if u_ref3If the value is more than 0, C is 1, otherwise, C is 0;

N＝4C+2B+A。

s13: according to the correspondence between N and the sector as shown in the following Table 1, it can be obtained

The sector in which it is located.

TABLE 1

N＝	3	1	5	4	6	2
							Sector numbering	Ⅰ	Ⅱ	Ⅲ	Ⅳ	Ⅴ	Ⅵ

According to a given voltage u_α、u_βWhen N is calculated to be 3, then

The SVPWM sector is sector I.

By designing the steps S11-S13, the judgment can be simply, conveniently, quickly and accurately made

The sector where the SVPWM is located.

Step S2: obtaining a reference voltage vector

Action time t of two non-zero basic voltage vectors of the SVPWM sector in one PWM period₁、t₂。

The method specifically comprises the following steps:

s21: the value of variable X, Y, Z is calculated according to the following equation:

wherein u is_dcT is the time of one PWM cycle.

S22: determining the action time t according to the corresponding relationship between the sectors and X, Y, Z and the action time shown in the following table 2₁、t₂。

Action time t of each basic voltage vector of six sectors₁、t₂The correspondence relationship between X, Y, Z and the sector is shown in table 2 below.

TABLE 2

The correspondence between the basic voltage vectors of the six sectors and the action time is shown in the following table 3. For the convenience of calculation, the action time of two basic voltage vectors of each sector is respectively used as t₁、t₂And (4) showing.

TABLE 3

For example,

the sector is a sector I, and two non-zero basic voltage vectors of the sector I are

Time of action t₁、t₂is-Z, X. X, Y, Z is calculated according to the formula, and action time t can be obtained by looking up table 2₁、t₂The value of (c).

By designing the steps S21-S22, the judgment can be simply, conveniently, quickly and accurately made

Action time t of two non-zero basic voltage vectors of the SVPWM sector in one PWM period₁、t₂。

Step S3: and calculating the action time after compensation.

According to the duration of action t₁、t₂And inverter dead time t_DThe compensated action time t is calculated by the following compensation calculation formula_1n、t_2n。

If the condition (i) is satisfied: t is t₁＞t_DAnd t is 2₂＞t_DA/2, then

If the condition (II) is met: condition is not satisfied, and t₁≥t₂Then, then

If the condition (c) is satisfied: the condition is not satisfied, and t₁＜t₂Then, then

If the condition (iv) is satisfied: if the first condition, the second condition and the third condition are not satisfied, the

Dead time t_DThe size of the switch is to avoid the simultaneous conduction of the upper and lower switch tubes of the same bridge arm, and considerThe dead time configuration is too small, so that two switching tubes of the same bridge arm can be directly connected, and the dead time effect can be amplified if the dead time configuration is too large.

In the present embodiment, the inverter dead time t_DThe value range of the bridge arm can be selected to be 2-5 mu s, and the two switching tubes of the same bridge arm can be prevented from being directly connected. Of course, the dead time t_DOther values can be taken and set according to actual conditions.

The establishment process of the compensation calculation formula comprises the following steps:

s31: within one PWM period, according to t₁、t₂And t_DThe magnitude relationship of the three classifies dead zone states into four categories:

dead zone state 1: t is t₁>t_DAnd t is₂>t_D；

Dead zone state 2: t is t₁>t_DAnd t is₂≤t_DOr t₁≤t_DAnd t is₂>t_D；

Dead zone state 3: t is t₁≤t_DAnd t is₂≤t_DAnd t is₁+t₂>t_D；

Dead zone state 4: t is t₁+t₂≤t_D。

S32: for the dead zone state 1: when t is₁>t_DAnd t is₂>t_DWhen t is_1n＝t₁+t_D/2，t_2n＝t₂+t_D/2。

S33: for the dead zone state 2:

when t is₁>t_DAnd t is₂≤t_DWhen t is₂>t_D2, then t_1n＝t₁+t_D/2，t_2n＝t₂+t_D/2；

If t₂≤t_D2, then t_1n＝t₁+t_D–t₂，t_2n＝2t₂；

When t is₁≤t_DAnd t is₂>t_DWhen t is₁>t_D2, then t_1n＝t₁+t_D/2，t_2n＝t₂+t_D/2；

If t₁≤t_D2, then t_1n＝2t₁，t_2n＝t₂+t_D–t₁。

S34: for dead zone state 3, when t₁≤t_DAnd t is₂≤t_DAnd t is₁+t₂>t_DThe method comprises the following steps:

if t₂≤t_DAnd t is 2₁>t₂Then t is_1n＝t₁+t_D–t₂，t_2n＝2t₂；

If t₁≤t_DAnd t is 2₂>t₁Then t is_1n＝2t₁，t_2n＝t₂+t_D–t₁；

If t₁>t_DAnd t is 2₂>t_D2, then t_1n＝t₁+t_D/2，t_2n＝t₂+t_D/2。

S35: for the dead zone state 4, when t₁+t₂≤t_DThe method comprises the following steps:

if t₂≤t_DAnd t is 2₁>t₂Then t is_1n＝t₁+t_D–t₂，t_2n＝2t₂；

If t₁≤t_DAnd t is 2₂>t₁Then t is_1n＝2t₁，t_2n＝t₂+t_D–t₁；

S36: and integrating S32, S33, S34 and S35 to obtain the compensation calculation formula.

Through designing S31-S36, the dead zone states are divided into four categories, then compensation time is calculated according to each dead zone state, and finally synthesis is carried out to obtain a final compensation calculation formula.

In the following, taking the sector I of SVPWM in fig. 3 as an example, the dead zone characteristic and the compensation method are analyzed, and the other five sectors are similar.

Set the non-zero basic voltage vector of sector I

And

respectively has an action time of t₁And t₂The dead time is t_DIn one PWM cycle, according to t₁、t₂And t_DThe magnitude relationship of the three classifies dead zone status into four main categories.

Dead zone state 1: t is t₁>t_DAnd t is₂>t_D；

Dead zone state 2: t is t₁>t_DAnd t is₂≤t_DOr t₁≤t_DAnd t is₂>t_D；

Dead zone state 3: t is t₁≤t_DAnd t is₂≤t_DAnd t is₁+t₂>t_D；

Dead zone state 4: t is t₁+t₂≤t_D。

On the premise of not changing the three-phase conduction sequence, t in the dead zone is not considered₁And t₂Compensating corresponding voltage vector action time, and setting the action time after compensation as t_1nAnd t_2nThe corresponding total compensation amount is t_1cAnd t_2c。

And secondly, analyzing and calculating the four types of dead zone states to obtain the compensation quantity of the SVPWM voltage vector action time and the time of the compensated voltage vector to act.

(21) For the dead zone state 1 (t)₁>t_DAnd t is₂>t_D). Waveform diagram in a complete PWM period and corresponding voltage vector action duration sum under six switching tube switching statesThe amplitude is shown in fig. 4, and the duration of one complete PWM cycle is set to T. Wherein, the horizontal axis is time, and the range is one PWM cycle; the vertical axis represents the resultant voltage amplitude corresponding to the (S1-S6) switch states. Sa represents a phase bridge arm, and comprises switching tubes S1 and S2; sb represents a b-phase bridge arm and comprises switching tubes S3 and S4; sc represents a c-phase bridge arm and comprises switching tubes S5 and S6.

And so on from left to right:

(a) the switch state (010101) is at the initial time of 0 and the action time of t_0hWhen the corresponding voltage vector is zero vector (N)_s42) the amplitude is zero.

(b) Switch state (000101) starting time t_0hDuration of action t_DWhen the corresponding voltage vector is zero vector (N)_s40), the amplitude is zero.

(c) The switch state (100101) has an action duration t₁–t_DCorresponding voltage vector is

The amplitude is 2/3.

(d) The duration of the switching state (100001) is t_DCorresponding voltage vector is

Amplitude of

(e) The switching state (101001) has an action duration t₂–t_DCorresponding voltage vector is

The amplitude is 2/3.

(f) The switching state (101000) has an action duration t_DThe corresponding voltage vector is the zero vector (N)_s5), the amplitude is 0.

(g) The action time of the switch state (101010) is T-2T₁–2t₂–t_D–2t_0hThe corresponding voltage vector is the zero vectorQuantity (N)_s21) and the amplitude is 0.

(h) The switching state (101000) has an action duration t_DThe corresponding voltage vector is the zero vector (N)_s5), the amplitude is 0.

(i) The switching state (101001) has an action duration t₂–t_DCorresponding voltage vector is

The amplitude is 2/3.

(g) The duration of the switching state (100001) is t_DCorresponding voltage vector is

Amplitude of

(k) The switch state (100101) has an action duration t₁–t_DCorresponding voltage vector is

The amplitude is 2/3.

(l) Switch state (000101) has an action duration t_DThe corresponding voltage vector is the zero vector (N)_s40), the amplitude is zero.

(m) switching state (010101) with action duration t_0h–t_DThe corresponding voltage vector is the zero vector (N)_s42) the amplitude is zero.

As can be seen from the analysis, the effect of t should be observed₁And t₂Two voltage vectors (41 and 37) of duration, i.e.

And

) Only t is acted on due to dead zone effect₁–t_DAnd t₂–t_DDuration, i.e. each less acts on t_DThe length of time. Except for the effective voltage vector

And

in addition, a harmonic voltage vector N is generated due to the dead zone effect_s33 when standing still, i.e.

Duration of action t_D。

According to the volt-second balance principle, the voltage vector

Effect of the actions and

and

two voltage vector contributions t_xTime equivalence, i.e.

Get t by solution_xIt is known that harmonic voltages are generated by the dead zone effect

The effect of the action is equivalent to that of

And

each compensate for t_DDead time of/2, then

And

only need to compensate for t again_DThe required reference voltage can be output by the voltage controller/2. When t is₁>t_DAnd t is₂>t_DWhen t is_1n＝t₁+t_D/2，t_2n＝t₂+t_D/2, corresponding total compensation t_1c＝t_D/2，t_2c＝t_D/2。

(22) For the dead zone state 2 (t)₁>t_DAnd t is₂≤t_DOr t₁≤t_DAnd t is₂>t_D)。t₁>t_DAnd t is₂≤t_DAnd t₁≤t_DAnd t is₂>t_DThe two states can be analogically analyzed. Here first with t₁>t_DAnd t is₂≤t_DThe analysis was performed as an example.

Under the dead zone condition, according to t₁、t₂And t_DThe waveform diagram in a complete PWM cycle (with the cycle duration being T) and the action durations and amplitudes of the voltage vectors corresponding to the six switching tube switch states are shown in FIG. 5, which should act on T₁And t₂Two voltage vectors of duration

And

due to the effect of the dead zone, the air gap,

act on t₁–t_DTo do so

Has no effect, and the dead zone effect generates a harmonic voltage vector

Duration of action t₂. The effect of the harmonic voltage vector action is equal to that of the voltage-second balance principle

And

two voltage vector contributions t₂Equivalent to/2 time equivalent to

And

each compensate for t₂A dead time of/2. Namely, equivalent to

And

respectively has a duration of action of t₁–t_D+t₂[ 2 ] and t₂/2. Then t is in this state condition₁And t₂After compensation is t_1n＝t₁+t_1c，t_2n＝t₂+t_2cAt this point, further discussion of the compensation case is needed:

(22-1) if t_2n>t_DAfter compensation, the switching state in the PWM period will become the dead-zone state 1. Order to

And

respectively has a duration of action of t₁And t₂In this dead-zone state 1, the compensated action time ((t)₁+t_1c–t_D)+t_D/2，(t₂+t_2c–t_D)+t_D/2) is equal to the time (t) over which the voltage vector should act₁，t₂) I.e. having t₁＝(t₁+t_1c–t_D)+t_D/2，t₂＝(t₂+t_2c–t_D)+t_D(ii)/2, from which the compensation quantities are determined to be t_1c＝t_D/2，t_2c＝t_D/2. When t is_2n>t_D(i.e. t)₂>t_DAt/2), t₁And t₂After compensation is t_1n＝t₁+t_D/2，t_2n＝t₂+t_D/2。

(22-2) if t_2n≤t_DLet us order

And

respectively has a duration of action of t₁And t₂Having t of₁＝(t₁+t_1c–t_D)+(t₂+t_2c)/2，t₂＝(t₂+t_2c) /2, calculating the compensation amount as t_1c＝t_D–t₂，t_2c＝t₂. When t is_2n≤t_D(i.e. t)₂≤t_DAt/2), t₁And t₂After compensation is t_1n＝t₁+t_D–t₂，t_2n＝2t₂。

(22-3) for the dead band state t₁≤t_DAnd t is₂>t_DSimply put the above t₁>t_DAnd t is₂≤t_DT in the compensation result₁And t₂And (4) interchanging. Namely:

if t_1n>t_D，t₁And t₂After compensation is t_1n＝t₁+t_D/2，t_2n＝t₂+t_D/2。

If t_1n≤t_D，t₁And t₂After compensation is t_1n＝2t₁，t_2n＝t₂+t_D–t₁。

(23) For dead zone state 3 (t)₁≤t_DAnd t is₂≤t_DAnd t is₁+t₂>t_D). In the dead zone state, according to t₁、t₂And t_DThe relationship between the magnitude and the voltage vector can be drawn as a waveform diagram in a complete PWM period (with the period duration being T) and the relationship between the voltage vector action duration and the amplitude corresponding to the switching states of six switching tubes is shown in FIG. 6, and the action T is the same₁And t₂Two voltage vectors of duration

And

both had no effect at all due to the dead zone effect. And harmonic voltage vectors generated by dead zone effects

Duration of action t₁+t₂–t_D. Harmonic voltage according to volt-second balance principle

The effect is equivalent to that of

And

each compensate (t)₁+t₂–t_D) A dead time of/2. Then t is at this state condition₁And t₂After compensation is t_1n0＝t₁+[t₁–(t₁+t₂–t_D)/2]＝t₁+(t₁–t₂+t_D)/2，t_2n0＝t₂+[t₂–(t₁+t₂–t_D)/2]＝t₂+(t₂–t₁+t_D) Similar to dead band state 2, the above compensation results need to be discussed further.

(23-1) if t_1n0≤t_DAnd t is_2n0≤t_DObtaining t₁+t₂≤t_DThis contradicts the condition of dead band state 3, which does not exist.

(23-2) if t_1n0>t_DAnd t is_2n0≤t_DI.e. after compensation becomes dead zone state 2 (t)₁>t_DAnd t is₂≤t_D) I.e. at t₂≤t_DAnd t is 2₁>t₂On the premise of (a), t₁And t₂The compensation amounts of (a) and (b) are respectively: t is t_1c＝t_D–t₂，t_2c＝t₂(ii) a After compensation are respectively t_1n＝t₁+t_D–t₂，t_2n＝2t₂。

(23-3) if t_2n0>t_DAnd t is_1n0≤t_DI.e. after compensation becomes dead zone state 2 (t)₁≤t_DAnd t is₂>t_D) I.e. at t₁≤t_DAnd t is 2₂>t₁On the premise of (a), t₁And t₂The compensation amounts of (a) and (b) are respectively: t is t_1c＝t₁，t_2c＝t_D–t₁(ii) a After compensation are respectively t_1n＝2t₁，t_2n＝t₂+t_D–t₁。

(23-4) if t_1n0>t_DAnd t is_2n0>t_DI.e. after compensation becomes dead-zone state 1 (t)₁>t_DAnd t is₂>t_D) I.e. at t₁>t_DAnd t is 2₂>t_DOn the premise of/2, t₁And t₂The compensation amounts of (a) and (b) are respectively: t is t_1c＝t_D/2，t_2c＝t_D2; after compensation are respectively t_1n＝t₁+t_D/2，t_2n＝t₂+t_D/2。

Dead zone state 3 (t)₁≤t_DAnd t is₂≤t_DAnd t is₁+t₂>t_D) The specific compensation results of (a) are shown in table 4 below.

TABLE 4

(24) For the dead zone state 4 (t)₁+t₂≤t_D). According to the above analysis steps, under the condition, the waveform diagram in a complete PWM period (with the period duration being T) and the relationship between the action duration and the amplitude of the voltage vector corresponding to the switching states of the six switching tubes are shown in FIG. 7, and the voltage vector

And

due to dead zone effect, the two have no effect at all, and harmonic voltage vector

Nor was there any effect. Then, at this time, t₁And t₂After compensation is t_1n＝t₁+t_1c，t_2n＝t₂+t_2cFurther discussion of the compensation results is provided below:

(24-1) if t_1n+t_2n≤t_DThe dead zone state 4 is still obtained after compensation, and the compensation is not in place, so that the situation should not occur.

(24-2) if t_1n≤t_DAnd t is_2n≤t_DAnd t is_1n+t_2n>t_DFurther compensation is made for other situations. The other cases here mean that compensation is performed under the following conditions (24-3), (24-4), and (24-5).

(24-3) if t_1n>t_DAnd t is_2n>t_DI.e. after compensation, becomes dead-zone state 1, i.e. demand t₁>t_DAnd t is 2₂>t_D/2, this is in phase with the dead band state 4 conditionContradictory, so none exists.

(24-4) if t_1n>t_DAnd t is_2n≤t_DI.e. after compensation becomes dead zone state 2 (t)₁>t_DAnd t is₂≤t_D) I.e. at t₂≤t_DAnd t is 2₁>t₂On the premise of (a), t₁And t₂After compensation is t_1n＝t₁+t_D–t₂，t_2n＝2t₂。

(24-5) if t_1n≤t_DAnd t is_2n>t_DI.e. after compensation becomes dead zone state 2 (t)₁≤t_DAnd t is₂>t_D) I.e. at t₁≤t_DAnd t is 2₂>t₁On the premise of (a), t₁And t₂After compensation is t_1n＝2t₁，t_2n＝t₂+t_D–t₁。

Dead zone state 4 (t)₁+t₂≤t_D) The specific compensation results of (a) are shown in table 5 below.

TABLE 5

The four dead zone states are integrated to obtain:

if the condition (i) is satisfied: t is t₁＞t_DAnd t is 2₂＞t_DA/2, then

If the condition (II) is met: condition is not satisfied, and t₁≥t₂Then, then

If the condition (c) is satisfied: the condition is not satisfied, and t₁＜t₂Then, then

If the condition (iv) is satisfied: if the first condition, the second condition and the third condition are not satisfied, the

Step S4: according to the compensated action time t_1n、t_2nAnd calculating to generate new six paths of PWM signals, and outputting the new six paths of PWM signals to the three-phase voltage source inverter.

According to t_1n、t_2nAnd calculating and generating new six paths of PWM signals through a space vector pulse width modulation algorithm, outputting the new six paths of PWM signals to the three-phase voltage source inverter, and controlling the on-off of six switching tubes of the three-phase voltage source inverter.

The dead-zone compensation method of the three-phase voltage source inverter of the embodiment is realized by the method according to the given voltage u_α、u_βDetermining a reference voltage vector

The SVPWM sector is located; to obtain

Action time t of two non-zero basic voltage vectors of the located sector in one PWM period₁、t₂(ii) a According to t₁、t₂And inverter dead time t_DFor the action time t₁、t₂Compensation is carried out, and the action time after compensation is t_1n、t_2n(ii) a According to the compensated action time t_1n、t_2nCalculating to generate new six paths of PWM signals, outputting the new six paths of PWM signals to the inverter, and controlling the on-off of six switching tubes of the inverter; the dead zone compensation method of the three-phase voltage source inverter has the advantages of high compensation precision, good compensation effect, high reliability, no need of any additional hardware, low economic cost and high transportability.

The dead zone compensation method of the three-phase voltage source inverter of the embodiment reconstructs 27 independent conduction states of a switching tube after adding the dead zone, analyzes the effective action time of the SVPWM basic voltage vector and the equivalent action time of the harmonic voltage vector to the basic voltage vector calculated according to the volt-second balance principle, obtains the actual action time of the basic voltage vector, and determines the compensation time of the SVPWM basic voltage vector. The influence of the dead zone on the action time of the SVPWM basic voltage vector is analyzed, the action time of the voltage vector is compensated, and no parameter is detected or additional hardware equipment is needed.

According to the dead zone compensation method of the three-phase voltage source inverter, when the inverter is provided with pure resistance load, the influence of the dead zone on the fundamental wave amplitude and harmonic content of output voltage can be completely compensated; when the inverter is provided with the resistance-inductance load, compared with the inverter without dead zones, the fundamental wave amplitude of the output voltage is obviously improved, and the harmonic content is obviously improved.

The dead-zone compensation method of the three-phase voltage source inverter aiming at the integrity of the SVPWM voltage vector of the embodiment judges the action time t of the SVPWM non-zero basic voltage vector₁、t₂And dead time t_DAnd then compensating the action time of the non-zero basic voltage vector according to the determined dead zone state category.

In the dead zone compensation method of the embodiment, the integrity of the SVPWM voltage vector is compensated by a method of reconstructing the voltage vector after adding the dead zone; compared with the traditional dead zone compensation method which needs hardware, the compensation method of the embodiment does not need any additional hardware, and has the advantages of low economic cost and high portability; compared with a compensation method needing to detect the polarity of current, the compensation method of the embodiment does not need to judge the polarity of a phase current zero crossing point, has high reliability, and can realize high-precision compensation of the voltage amplitude only through simple analysis and volt-second balance calculation; compared with the dead zone compensation method for measuring the dead zone compensation effect through phase current harmonics, the compensation method provided by the embodiment analyzes the influence of the dead zone effect on the integrity of the output voltage and the voltage vector of the inverter, and realizes effective compensation on the amplitude and the harmonics of the output voltage.

In the second embodiment, based on the design of the dead-time compensation method for the three-phase voltage source inverter, the present embodiment further provides a dead-time compensation system for the three-phase voltage source inverter, which includes a sector judgment module, an action time acquisition module, a compensation calculation module, a PWM signal generation module, and a three-phase voltage source inverter, as shown in fig. 9.

A sector judging module for judging the sector according to the given voltage u_α、u_βDetermining a reference voltage vector

The SVPWM sector is located; wherein u is_α、u_βThe voltage amplitudes of an alpha axis and a beta axis under the two-phase static coordinate system are respectively; reference voltage vector

Is u under a two-phase stationary coordinate system_α、u_βThe resultant vector of (2).

An action time acquisition module for acquiring a reference voltage vector

Action time t of two non-zero basic voltage vectors of the SVPWM sector in one PWM period₁、t₂。

A compensation calculation module for calculating the compensation according to the action time t₁、t₂And inverter dead time t_DThe compensated action time t is calculated by the following compensation calculation formula_1n、t_2n：

If the condition (i) is satisfied: t is t₁＞t_DAnd t is 2₂＞t_DA/2, then

If the condition (II) is met: condition is not satisfied, and t₁≥t₂Then, then

If the condition (c) is satisfied: the condition is not satisfied, and t₁＜t₂Then, then

If the condition (iv) is satisfied: if the first condition, the second condition and the third condition are not satisfied, the

A PWM signal generation module for generating a PWM signal according to the compensated action time t_1n、t_2nAnd calculating and generating new six paths of PWM signals through a space vector pulse width modulation algorithm, outputting the new six paths of PWM signals to the three-phase voltage source inverter, and controlling the output voltage of the three-phase voltage source inverter.

And the three-phase voltage source inverter is used for receiving the PWM signals output by the PWM signal generation module, outputting three-phase voltage and applying the three-phase voltage to a motor or other electric equipment.

In this embodiment, the sector determining module is specifically configured to:

(11) the variable u is calculated according to the following formula_ref1、u_ref2、u_ref3A value of (d);

(12) value of calculation variable A, B, C, N:

if u_ref1If the value is more than 0, A is equal to 1, otherwise, A is equal to 0;

if u_ref2If the value is more than 0, B is equal to 1, otherwise, B is equal to 0;

if u_ref3If the value is more than 0, C is 1, otherwise, C is 0;

N＝4C+2B+A；

(13) according to the corresponding relation between N and the sector, the method can obtain

The sector in which it is located.

In this embodiment, the action time acquiring module is specifically configured to:

(21) the value of variable X, Y, Z is calculated according to the following equation:

wherein u is_dcThe value of the direct current bus voltage is T, and T is the time of one PWM period;

(22) determining action time t according to corresponding relation between sectors and X, Y, Z and action time₁、t₂。

In this embodiment, the compensation calculating module includes a compensation formula establishing unit, and the compensation formula establishing unit is specifically configured to:

(31) within one PWM period, according to t₁、t₂And t_DThe magnitude relationship of the three classifies dead zone states into four categories:

dead zone state 1: t is t₁>t_DAnd t is₂>t_D；

Dead zone state 2: t is t₁>t_DAnd t is₂≤t_DOr t₁≤t_DAnd t is₂>t_D；

Dead zone state 3: t is t₁≤t_DAnd t is₂≤t_DAnd t is₁+t₂>t_D；

Dead zone state 4: t is t₁+t₂≤t_D；

(32) For the dead zone state 1: when t is₁>t_DAnd t is₂>t_DWhen t is_1n＝t₁+t_D/2，t_2n＝t₂+t_D/2；

(33) For the dead zone state 2:

when t is₁>t_DAnd t is₂≤t_DWhen t is₂>t_D2, then t_1n＝t₁+t_D/2，t_2n＝t₂+t_D/2；

If t₂≤t_D2, then t_1n＝t₁+t_D–t₂，t_2n＝2t₂；

When t is₁≤t_DAnd t is₂>t_DWhen t is₁>t_D2, then t_1n＝t₁+t_D/2，t_2n＝t₂+t_D/2；

If t₁≤t_D2, then t_1n＝2t₁，t_2n＝t₂+t_D–t₁；

(34) For dead zone state 3, when t₁≤t_DAnd t is₂≤t_DAnd t is₁+t₂>t_DThe method comprises the following steps:

if t₂≤t_DAnd t is 2₁>t₂Then t is_1n＝t₁+t_D–t₂，t_2n＝2t₂；

If t₁≤t_DAnd t is 2₂>t₁Then t is_1n＝2t₁，t_2n＝t₂+t_D–t₁；

If t₁>t_DAnd t is 2₂>t_D2, then t_1n＝t₁+t_D/2，t_2n＝t₂+t_D/2；

(35) For the dead zone state 4, when t₁+t₂≤t_DThe method comprises the following steps:

if t₂≤t_DAnd t is 2₁>t₂Then t is_1n＝t₁+t_D–t₂，t_2n＝2t₂；

If t₁≤t_DAnd t is 2₂>t₁Then t is_1n＝2t₁，t_2n＝t₂+t_D–t₁；

(36) And (32) to (35) are integrated to obtain the compensation calculation formula.

The working process of the three-phase voltage source inverter dead-time compensation system has been described in detail in the above-mentioned three-phase voltage source inverter dead-time compensation method, and is not described herein again.

The dead-zone compensation system of the three-phase voltage source inverter of the embodiment is realized by the method according to the given voltage u_α、u_βDetermining a reference voltage vector

The SVPWM sector is located; to obtain

Action time t of two non-zero basic voltage vectors of the located sector in one PWM period₁、t₂(ii) a According to t₁、t₂And inverter dead time t_DFor the action time t₁、t₂Compensation is carried out, and the action time after compensation is t_1n、t_2n(ii) a According to the compensated action time t_1n、t_2nCalculating to generate new six paths of PWM signals, outputting the new six paths of PWM signals to the inverter, and controlling the on-off of six switching tubes of the inverter; the dead zone compensation method of the three-phase voltage source inverter has the advantages of high compensation precision, good compensation effect, high reliability, no need of any additional hardware, low economic cost and high transportability.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions.

Claims (8)

1. A dead zone compensation method of a three-phase voltage source inverter is characterized by comprising the following steps: the method comprises the following steps:

(1) according to a given voltage u_α、u_βJudgment ofReference voltage vector

The SVPWM sector is located;

wherein u is_α、u_βThe voltage amplitudes of an alpha axis and a beta axis under the two-phase static coordinate system are respectively; reference voltage vector

Is u under a two-phase stationary coordinate system_α、u_βThe resultant vector of (a);

(2) obtaining a reference voltage vector

Action time t of two non-zero basic voltage vectors of the SVPWM sector in one PWM period₁、t₂；

(3) According to the duration of action t₁、t₂And inverter dead time t_DThe compensated action time t is calculated by the following compensation calculation formula_1n、t_2n：

If the condition (i) is satisfied: t is t₁＞t_DAnd t is 2₂＞t_DA/2, then

If the condition (II) is met: condition is not satisfied, and t₁≥t₂Then, then

If the condition (c) is satisfied: the condition is not satisfied, and t₁＜t₂Then, then

If the condition is satisfiedFourthly, the method comprises the following steps: if the first condition, the second condition and the third condition are not satisfied, the

(4) According to the compensated action time t_1n、t_2nAnd calculating to generate new six paths of PWM signals, and outputting the new six paths of PWM signals to the three-phase voltage source inverter.

2. The method of claim 1, wherein: the step (1) specifically comprises the following steps:

(11) the variable u is calculated according to the following formula_ref1、u_ref2、u_ref3A value of (d);

(12) value of calculation variable A, B, C, N:

if u_ref1If the value is more than 0, A is equal to 1, otherwise, A is equal to 0;

if u_ref2If the value is more than 0, B is equal to 1, otherwise, B is equal to 0;

if u_ref3If the value is more than 0, C is 1, otherwise, C is 0;

N＝4C+2B+A；

(13) according to the corresponding relation between N and the sector, the method can obtain

The sector in which it is located.

3. The method of claim 1, wherein: the step (2) specifically comprises the following steps:

(21) the value of variable X, Y, Z is calculated according to the following equation:

wherein u is_dcIs the value of the DC bus voltage, T isThe time of one PWM cycle;

(22) determining action time t according to corresponding relation between sectors and X, Y, Z and action time₁、t₂。

4. The method of claim 1, wherein: the establishment process of the compensation calculation formula comprises the following steps:

(31) within one PWM period, according to t₁、t₂And t_DThe magnitude relationship of the three classifies dead zone states into four categories:

dead zone state 1: t is t₁>t_DAnd t is₂>t_D；

Dead zone state 2: t is t₁>t_DAnd t is₂≤t_DOr t₁≤t_DAnd t is₂>t_D；

Dead zone state 3: t is t₁≤t_DAnd t is₂≤t_DAnd t is₁+t₂>t_D；

Dead zone state 4: t is t₁+t₂≤t_D；

(32) For the dead zone state 1: when t is₁>t_DAnd t is₂>t_DWhen t is_1n＝t₁+t_D/2，t_2n＝t₂+t_D/2；

(33) For the dead zone state 2:

when t is₁>t_DAnd t is₂≤t_DWhen t is₂>t_D2, then t_1n＝t₁+t_D/2，t_2n＝t₂+t_D/2；

If t₂≤t_D2, then t_1n＝t₁+t_D–t₂，t_2n＝2t₂；

When t is₁≤t_DAnd t is₂>t_DWhen t is₁>t_D2, then t_1n＝t₁+t_D/2，t_2n＝t₂+t_D/2；

If t₁≤t_D2, then t_1n＝2t₁，t_2n＝t₂+t_D–t₁；

(34) For dead zone state 3, when t₁≤t_DAnd t is₂≤t_DAnd t is₁+t₂>t_DThe method comprises the following steps:

if t₂≤t_DAnd t is 2₁>t₂Then t is_1n＝t₁+t_D–t₂，t_2n＝2t₂；

If t₁≤t_DAnd t is 2₂>t₁Then t is_1n＝2t₁，t_2n＝t₂+t_D–t₁；

If t₁>t_DAnd t is 2₂>t_D2, then t_1n＝t₁+t_D/2，t_2n＝t₂+t_D/2；

(35) For the dead zone state 4, when t₁+t₂≤t_DThe method comprises the following steps:

if t₂≤t_DAnd t is 2₁>t₂Then t is_1n＝t₁+t_D–t₂，t_2n＝2t₂；

If t₁≤t_DAnd t is 2₂>t₁Then t is_1n＝2t₁，t_2n＝t₂+t_D–t₁；

(36) And (32) to (35) are integrated to obtain the compensation calculation formula.

5. A three-phase voltage source inverter dead zone compensation system is characterized in that: the method comprises the following steps:

a sector judging module for judging the sector according to the given voltage u_α、u_βDetermining a reference voltage vector

The SVPWM sector is located; wherein u is_α、u_βThe voltage amplitudes of an alpha axis and a beta axis under the two-phase static coordinate system are respectively; reference voltage vector

Is u under a two-phase stationary coordinate system_α、u_βThe resultant vector of (a);

an action time acquisition module for acquiring a reference voltage vector

Action time t of two non-zero basic voltage vectors of the SVPWM sector in one PWM period₁、t₂；

A compensation calculation module for calculating the compensation according to the action time t₁、t₂And inverter dead time t_DThe compensated action time t is calculated by the following compensation calculation formula_1n、t_2n：

If the condition (i) is satisfied: t is t₁＞t_DAnd t is 2₂＞t_DA/2, then

If the condition (II) is met: condition is not satisfied, and t₁≥t₂Then, then

If the condition (c) is satisfied: the condition is not satisfied, and t₁＜t₂Then, then

If the condition (iv) is satisfied: if the first condition, the second condition and the third condition are not satisfied, the

A PWM signal generation module for generating a PWM signal according to the compensated action time t_1n、t_2nCalculating to generate new six paths of PWM signals, and outputting the new six paths of PWM signals to the three-phase voltage source inverter;

and the three-phase voltage source inverter is used for receiving the PWM signal output by the PWM signal generation module and outputting three-phase voltage.

6. The system of claim 5, wherein: the sector judgment module is specifically configured to:

(11) the variable u is calculated according to the following formula_ref1、u_ref2、u_ref3A value of (d);

(12) value of calculation variable A, B, C, N:

if u_ref1If the value is more than 0, A is equal to 1, otherwise, A is equal to 0;

if u_ref2If the value is more than 0, B is equal to 1, otherwise, B is equal to 0;

if u_ref3If the value is more than 0, C is 1, otherwise, C is 0;

N＝4C+2B+A；

(13) according to the corresponding relation between N and the sector, the method can obtain

The sector in which it is located.

7. The system of claim 5, wherein: the action time acquisition module is specifically configured to:

(21) the value of variable X, Y, Z is calculated according to the following equation:

wherein u is_dcThe value of the direct current bus voltage is T, and T is the time of one PWM period;

(22) determining action time t according to corresponding relation between sectors and X, Y, Z and action time₁、t₂。

8. The system of claim 5, wherein: the compensation calculation module comprises a compensation formula establishing unit, and the compensation formula establishing unit is specifically used for:

(31) within one PWM period, according to t₁、t₂And t_DThe magnitude relationship of the three classifies dead zone states into four categories:

dead zone state 1: t is t₁>t_DAnd t is₂>t_D；

Dead zone state 2: t is t₁>t_DAnd t is₂≤t_DOr t₁≤t_DAnd t is₂>t_D；

Dead zone state 3: t is t₁≤t_DAnd t is₂≤t_DAnd t is₁+t₂>t_D；

Dead zone state 4: t is t₁+t₂≤t_D；

(32) For the dead zone state 1: when t is₁>t_DAnd t is₂>t_DWhen t is_1n＝t₁+t_D/2，t_2n＝t₂+t_D/2；

(33) For the dead zone state 2:

when t is₁>t_DAnd t is₂≤t_DWhen t is₂>t_D2, then t_1n＝t₁+t_D/2，t_2n＝t₂+t_D/2；

If t₂≤t_D2, then t_1n＝t₁+t_D–t₂，t_2n＝2t₂；

When t is₁≤t_DAnd t is₂>t_DWhen t is₁>t_D2, then t_1n＝t₁+t_D/2，t_2n＝t₂+t_D/2；

If t₁≤t_D2, then t_1n＝2t₁，t_2n＝t₂+t_D–t₁；

(34) For dead zone state 3, when t₁≤t_DAnd t is₂≤t_DAnd t is₁+t₂>t_DThe method comprises the following steps:

if t₂≤t_DAnd t is 2₁>t₂Then t is_1n＝t₁+t_D–t₂，t_2n＝2t₂；

If t₁≤t_DAnd t is 2₂>t₁Then t is_1n＝2t₁，t_2n＝t₂+t_D–t₁；

If t₁>t_DAnd t is 2₂>t_D2, then t_1n＝t₁+t_D/2，t_2n＝t₂+t_D/2；

(35) For the dead zone state 4, when t₁+t₂≤t_DThe method comprises the following steps:

if t₂≤t_DAnd t is 2₁>t₂Then t is_1n＝t₁+t_D–t₂，t_2n＝2t₂；

If t₁≤t_DAnd t is 2₂>t₁Then t is_1n＝2t₁，t_2n＝t₂+t_D–t₁；

(36) And (32) to (35) are integrated to obtain the compensation calculation formula.

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