CN103973152B - A kind of pulse width modulation control method and device - Google Patents

Abstract

The invention discloses a kind of pulse width modulation control method, including: the pulse width of threephase switch pipe in acquisition switch periods；Obtain the first action time of pass-through state ST in described switch periods；According to described pulse width and described first action time, the second action time of non-straight-through zero state in obtaining described switch periods；According to synthesizing described switch periods, described pulse width, described first action time and described second action time three-phase pulse bandwidth modulation signals, wherein, described pass-through state ST and described non-straight-through zero state lay respectively at crest and the wave trough position of carrier wave.Correspondingly, the invention also discloses a kind of PWM and control device.Use the present invention, can directly measure the crest voltage on dc bus, and then directly busbar voltage is controlled.

Description

A kind of pulse width modulation control method and device

Technical field

The present invention relates to control technical field, particularly relate to a kind of pulse width modulation control method and device.

Background technology

Inverter (Inverter) is that one is transformed into alternating current (direct current energy (battery, accumulator jar) As be that 220V, 50Hz are sinusoidal wave) device or equipment, including voltage source inverter, current source inverter and Z-source inverter (Z-source inverter is called for short ZSI).Generally, the control mode of inverter uses pulse width Modulation (Pulse Width Modulation, PWM) control method, in traditional PWM control method, The state of switching tube includes 8 non-pass-through states, wherein, 6 effective status V1 (001), V2 (010), V3 (011), V4 (100), V5 (101), V6 (110) and 2 zero states V0 (000), V7 (111), 1 represents Conducting, 0 represents shutoff.In voltage source inverter and current source inverter, lower three switching tubes of brachium pontis State is contrary with the state of upper three switching tubes of brachium pontis, and a switch periods is by 2 effective statuses therein and 2 Individual zero state synthesizes；In Z-source inverter, switch periods is except including 2 effective statuses and 2 zero Outside state, also including special pass-through state ST, upper and lower two switching tubes of the most same brachium pontis simultaneously turn on.

As it is shown in figure 1, Fig. 1 is the circuit theory diagrams of a kind of Z-source inverter provided in prior art, In Fig. 1, inductance L1, inductance L2 and electric capacity C1, electric capacity C2 constitute Z source network, switch transistor T 1～open Closing pipe T6 and constitute inverter bridge, wherein T1, T3, T5 are referred to as upper brachium pontis, and T2, T4, T6 are referred to as lower brachium pontis. When the duty of Z-source inverter is pass-through state ST, diode D end, dc bus because of upper, Lower switching tube is straight-through and short-circuit, now DC bus-bar voltage V_PN=0；When the duty of Z-source inverter is non- During pass-through state, diode D turns on, now DC bus-bar voltage V_PN=V_DC(V_DCIt is referred to as busbar voltage Peak value), after inverter bridge inversion, obtain exchange output.But in the pulse width of existing Z-source inverter In modulation control method, pass-through state ST inserts the null vector being positioned at the crest B and trough A of carrier wave respectively Between amount V0 (000) and V7 (111), as in figure 2 it is shown, Fig. 2 vows for a kind of state provided in prior art Amount schematic diagram, in figure, the state in a switch periods is changed to (assume brachium pontis in certain switch periods The effective status of breaker in middle pipe is 100 and 110): pass-through state ST-> zero state 000-> effective status 100-> Effective status 110-> zero state 111-> pass-through state ST-> zero state 111-> effective status 110-> effective status 100-> zero state 000-> pass-through state ST.Visible in a switch periods, pass-through state ST occurs 2 Secondary, DC bus-bar voltage V_PNIn pulsating waveform, and the carrier frequency in pulse width modulation (PWM) control method Rate is the highest, therefore, causes DC bus-bar voltage V_PNIt is difficult to sample.Prior art typically all uses electric capacity Voltage close loop control method obtains DC bus-bar voltage, i.e. controls the voltage V on electric capacity C1 or C2_CKeep perseverance Fixed, thus obtain busbar voltage peak value V_DC=V_in/(1-2d₀), wherein, d₀For straight-through dutycycle.But, should Method has the disadvantage in that capacitance voltage V_CWith busbar voltage peak value V_DCBetween be not linear relationship, although energy Control capacitance voltage V_CKeep constant, but V_DCCan change, busbar voltage peak value with straight-through change in duty cycle V_DCIt is easy to fluctuation or deviates expected value, and busbar voltage peak value V_DCSwitching tube may be damaged time too high.

Summary of the invention

The embodiment of the present invention provides a kind of pulse width modulation control method and device, can directly measure direct current female Crest voltage on line, thus can directly busbar voltage be controlled.

The embodiment of the present invention provides a kind of pulse width modulation control method, including:

Obtain switch periods T_sThe pulse width of interior threephase switch pipe, is expressed as T_as、T_bs、T_cs；

Obtain pass-through state ST in described switch periods first action time T_sh；

According to described pulse width and described first action time, non-straight-through zero shape in obtaining described switch periods State second action time T₀；

During according to described switch periods, described pulse width, described first action time and described second effect Between synthesize three-phase pulse bandwidth modulation signals, wherein, described pass-through state ST and described non-straight-through zero state are divided It is not positioned at crest and the wave trough position of carrier wave, the pulse width of described three-phase pulse bandwidth modulation signals table respectively It is shown as T_ga、T_gb、T_gc；

As a example by first sector, the on off state change order in switch periods Ts is: V₀(000)、V₄ (100)、V₆(110), pass-through state ST, V₆(110)、V₄(100)、V₀(000), or be: V₇ (111)、V₆(110)、V₄(100), pass-through state ST, V₄(100)、V₆(110)、V₇(111), Correspondingly, the control method of other each sector is identical.

Wherein, described according to described pulse width with described first action time, obtain in described switch periods Non-straight-through zero state second action time T₀, including:

Relatively pulse width T of described threephase switch pipe_as、T_bs、T_csSize, it is thus achieved that maximum of T_max, minimum Value T_minWith intermediate value T_mid, i.e. T_min≤T_mid≤T_max；

According to described first action time T_shWith described minima T_minDetermine side-play amount T_f, T_f=T_sh-T_min；

According to described switch periods T_s, described maximum of T_maxWith described side-play amount T_f, calculate described second effect Time T₀For: T₀=T_s-(T_max+T_f)。

Wherein, described according to described switch periods, described pulse width, described first action time and described Second action time synthesized three-phase pulse bandwidth modulation signals, including:

Relatively more described second action time T₀With zero size；

If T₀>=0, according to described side-play amount T_fPulse width T with described threephase switch pipe_as、T_bs、T_csSynthesis Three-phase pulse bandwidth modulation signals, wherein, pulse width T of described three-phase pulse bandwidth modulation signals_ga、T_gb、 T_gcIt is respectively as follows:

$\left\{\begin{array}{c}{T}_{ga}=T_{as}+T_f\\ T_{gb}=T_{bs}+T_f\\ T_{gc}=T_{cs}+T_f\end{array}\right.$

If T₀＜ 0, according to described switch periods T_s, first action time T_shPulse with described threephase switch pipe Width T_as、T_bs、T_csSynthesis three-phase pulse bandwidth modulation signals, wherein, described three-phase pulse width modulated is believed Number pulse width T_ga、T_gb、T_gcIt is respectively as follows:

$\left\{\begin{array}{c}{T}_{ga}=\frac{T_s-T_{sh}}{T_{\max }-T_{\min }}(T_{as}-T_{\min })\\ T_{gb}=\frac{T_s-T_{sh}}{T_{\max }-T_{\min }}(T_{bs}-T_{\min })\\ T_{gc}=\frac{T_s-T_{sh}}{T_{\max }-T_{\min }}(T_{cs}-T_{\min })\end{array}\right.$

Wherein, described acquisition switch periods T_sThe pulse width of interior threephase switch pipe, including:

Voltage V according to A, B, C three-phase voltage_a、V_b、V_c, expectation voltage V on dc bus_DCWith open Close cycle T_s, it is thus achieved that pulse width T of described threephase switch pipe_as、T_bs、T_csIt is respectively as follows:

$\left\{\begin{array}{c}{T}_{as}=\frac{V_a}{V_{DC}}\·T_s\\ T_{bs}=\frac{V_b}{V_{DC}}\·T_s\\ T_{cs}=\frac{V_c}{V_{DC}}\·T_s\end{array}\right.$

Wherein, also include:

Within the action time of described non-straight-through zero state, DC bus-bar voltage is sampled, it is thus achieved that direct current is female Line crest voltage.

Correspondingly, present invention also offers a kind of pulse width modulation and control device, including:

First acquisition module, is used for obtaining switch periods T_sThe pulse width of interior threephase switch pipe, is expressed as T_as、T_bs、T_cs；

Second acquisition module, for obtain pass-through state ST in described switch periods first action time T_sh；

3rd acquisition module, for according to described pulse width and described first action time, opens described in acquisition In the cycle of pass non-straight-through zero state second action time T₀；

Synthesis module, for according to described switch periods, described pulse width, described first action time and Synthesize three-phase pulse bandwidth modulation signals described second action time, wherein, described pass-through state ST and described Non-straight-through zero state lays respectively at crest and the wave trough position of carrier wave, described three-phase pulse bandwidth modulation signals Pulse width is expressed as T_ga、T_gb、T_gc；

As a example by first sector, the on off state change order in switch periods Ts is: V₀(000)、V₄ (100)、V₆(110), pass-through state ST, V₆(110)、V₄(100)、V₀(000), or be: V₇ (111)、V₆(110)、V₄(100), pass-through state ST, V₄(100)、V₆(110)、V₇(111), Correspondingly, the control method of other each sector is identical.

Wherein, described 3rd acquisition module includes:

Comparing unit, for pulse width T of relatively described threephase switch pipe_as、T_bs、T_csSize, it is thus achieved that Maximum of T_max, minima T_minWith intermediate value T_mid, i.e. T_min≤T_mid≤T_max；

Choose unit, for according to described first action time T_shWith described minima T_minDetermine side-play amount T_f, T_f=T_sh-T_min；

Computing unit, for according to described switch periods T_s, described maximum of T_maxWith described side-play amount T_f, meter Calculate described second action time T₀For: T₀=T_s-(T_max+T_f)。

Wherein, described synthesis module includes:

Judging unit, for relatively more described second action time T₀With zero size；

First synthesis unit, if for T₀>=0, according to described side-play amount T_fPulse with described threephase switch pipe Width T_as、T_bs、T_csSynthesis three-phase pulse bandwidth modulation signals, wherein, described three-phase pulse width modulated is believed Number pulse width T_ga、T_gb、T_gcIt is respectively as follows:

$\left\{\begin{array}{c}{T}_{ga}=T_{as}+T_f\\ T_{gb}=T_{bs}+T_f\\ T_{gc}=T_{cs}+T_f\end{array}\right.$

Second synthesis unit, if for T₀＜ 0, according to described switch periods T_s, first action time T_shAnd institute State pulse width T of threephase switch pipe_as、T_bs、T_csSynthesis three-phase pulse bandwidth modulation signals, wherein, described Pulse width T of three-phase pulse bandwidth modulation signals_ga、T_gb、T_gcIt is respectively as follows:

$\left\{\begin{array}{c}{T}_{ga}=\frac{T_s-T_{sh}}{T_{\max }-T_{\min }}(T_{as}-T_{\min })\\ T_{gb}=\frac{T_s-T_{sh}}{T_{\max }-T_{\min }}(T_{bs}-T_{\min })\\ T_{gc}=\frac{T_s-T_{sh}}{T_{\max }-T_{\min }}(T_{cs}-T_{\min })\end{array}\right.$

Wherein, described first acquisition module is for the voltage V according to A, B, C three-phase voltage_a、V_b、V_c、 Expectation voltage V on dc bus_DCWith switch periods T_s, it is thus achieved that pulse width T of described threephase switch pipe_as、 T_bs、T_csIt is respectively as follows:

$\left\{\begin{array}{c}{T}_{as}=\frac{V_a}{V_{DC}}\·T_s\\ T_{bs}=\frac{V_b}{V_{DC}}\·T_s\\ T_{cs}=\frac{V_c}{V_{DC}}\·T_s\end{array}\right.$

Wherein, also include:

Sampling module, for adopting DC bus-bar voltage within the action time of described non-straight-through zero state Sample, it is thus achieved that dc bus crest voltage.

Implement the embodiment of the present invention, by removing one of them non-straight-through zero state, by whole pass-through state ST Inserting the active position of this non-straight-through zero state, meanwhile, the action time of this non-straight-through zero state is loaded onto separately On the action time of one non-straight-through zero state so that in a switch periods, pass-through state ST only occurs 1 time, Non-straight-through zero state also only one of which.Non-straight-through zero state and pass-through state ST mono-are positioned at crest, another It is positioned at trough, thus DC bus-bar voltage of can sampling within the action time of pass-through state ST easily, directly Measure the crest voltage on dc bus in Z-source inverter, and then can directly busbar voltage be controlled.

Accompanying drawing explanation

In order to be illustrated more clearly that the embodiment of the present invention or technical scheme of the prior art, below will be to enforcement In example or description of the prior art, the required accompanying drawing used is briefly described, it should be apparent that, describe below In accompanying drawing be only some embodiments of the present invention, for those of ordinary skill in the art, do not paying On the premise of going out creative work, it is also possible to obtain other accompanying drawing according to these accompanying drawings.

Fig. 1 is the circuit theory diagrams of a kind of Z-source inverter provided in prior art；

Fig. 2 is a kind of state vector schematic diagram provided in prior art；

Fig. 3 is the schematic flow sheet of a kind of pulse width modulation control method that the embodiment of the present invention provides；

Fig. 4 is a kind of state vector schematic diagram that the embodiment of the present invention provides；

Fig. 5 is the structural representation of a kind of pulse width modulation control device of the embodiment of the present invention；

Fig. 6 is the structural representation of a kind of 3rd acquisition module in Fig. 5；

Fig. 7 is the structural representation of a kind of synthesis module in Fig. 5.

Detailed description of the invention

Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clearly Chu, be fully described by, it is clear that described embodiment be only the present invention a part of embodiment rather than Whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art are not making creation The every other embodiment obtained under property work premise, broadly falls into the scope of protection of the invention.

The invention provides a kind of pulse width modulation control method and device, by pass-through state ST and non-straight-through Zero state inserts crest and the wave trough position of carrier wave respectively, thus can be within the action time of non-straight-through zero state DC bus-bar voltage is sampled, can directly measure the crest voltage of dc bus, thus can be directly to mother Line voltage carries out Control of Voltage.It is described in greater detail individually below.

See the flow process that Fig. 3, Fig. 3 are a kind of pulse width modulation control methods that the embodiment of the present invention provides to show Being intended to, in embodiments of the present invention, described control method comprises the following steps.

S101: obtain switch periods T_sThe pulse width of interior threephase switch pipe, is expressed as T_as、T_bs、T_cs。

Concrete, according to the voltage V of A, B, C three-phase voltage_a、V_b、V_c, expectation electricity on dc bus Pressure V_DCWith switch periods T_s, it is thus achieved that pulse width T of described threephase switch pipe_as、T_bs、T_csIt is respectively as follows:

$\left\{\begin{array}{c}{T}_{as}=\frac{V_a}{V_{DC}}\·T_s\\ T_{bs}=\frac{V_b}{V_{DC}}\·T_s\\ T_{cs}=\frac{V_c}{V_{DC}}\·T_s\end{array}\right.$

Wherein, the expectation voltage V on dc bus_DCExpectation crest voltage for dc bus.

S102: obtain pass-through state ST in described switch periods first action time T_sh。

When inverter bridge is in pass-through state ST, the switching tube in inverter bridge upper and lower bridge arm simultaneously turns on, quite In dc bus short circuit, now, input power is charged to the electric capacity of Z source network, ac output end Voltage is 0.During pass-through state ST, the capacitance energy storage of Z source network makes the direct current under non-pass-through state female The voltage peak of line increases.Concrete, pass-through state ST first action time T_shCan enter according to actual needs Row arrange, the embodiment of the present invention to first action time T_shValue do not limit.

S103: according to described pulse width and described first action time, non-straight in obtaining described switch periods Logical zero state second action time T₀。

The non-pass-through state of Z-source inverter include 6 effective status V1 (001), V2 (010), V3 (011), V4 (100), V5 (101), V6 (110) and 2 zero states V₀(000)、V₇(111), at traditional PWM In control method, in a switch periods, include 2 effective statuses, 2 non-straight-through zero states and pass-through state ST.Wherein, non-straight-through zero state inserts crest and the trough of carrier wave respectively, and pass-through state ST is inserted respectively Enter to be positioned in the non-straight-through zero state of crest and wave trough position (as shown in Figure 2), in fig. 2, effective status For V4 (100) and V6 (110), the state of the threephase switch pipe in a switch periods is changed to: pass-through state ST-> zero state 000-> effective status 100-> effective status 110-> zero state 111-> pass-through state ST-> zero shape State 111-> effective status 110-> effective status 100-> zero state 000-> pass-through state ST.Visible open at one In the cycle of pass, pass-through state ST occurs 2 times, owing to carrier frequency is the highest, therefore, causes dc bus Voltage is difficult to acquisition of directly sampling.

In the PWM control method of the embodiment of the present invention, remove one of them non-straight-through zero state, by whole Pass-through state ST inserts the active position of this non-straight-through zero state, meanwhile, during the effect of this non-straight-through zero state Between be loaded onto on the action time of another non-straight-through zero state.Such as: the situation in Fig. 2 uses the present invention After method, the on off state of the threephase switch pipe in switch periods is changed to: zero state 000-> effective status 100-> effective status 110-> pass-through state ST-> effective status 110-> effective status 100-> zero state 000 (as Shown in Fig. 4, Fig. 4 is a kind of state vector schematic diagram that the embodiment of the present invention provides).It can be seen that it is straight-through State ST is only present in the wave trough position of carrier wave, and non-straight-through zero state is only present in the crest location of carrier wave.Class As, pass-through state ST may be located at crest location, rather than straight-through zero state can be located at wave trough position, this Bright without limitation.Sum it up, in the PWM control method that the present invention provides, a switch periods Middle pass-through state ST only occurs 1 time, and at crest B or the trough location A of carrier wave, non-straight-through zero state is also Only one of which, at trough A or the crest B location of carrier wave, non-straight-through zero state is with pass-through state ST respectively Occupying crest and the wave trough position of carrier wave, i.e. one is positioned at crest, and another is positioned at trough.

Concrete, the method for the action time obtaining non-straight-through zero state is: 1. to described switch periods T_sInterior three Pulse width T of phase switching tube_as、T_bs、T_csCompare acquisition maximum of T_max, minima T_minAnd intermediate value T_mid, i.e. meet T_min≤T_mid≤T_max, such as: in first sector, have T_min=T_cs, T_mid=T_bs, T_max=T_as。 2. according to described first action time T_shWith described minima T_minDetermine side-play amount T_f, T_f=T_sh-T_min.3. root According to described switch periods T_s, described maximum of T_maxWith described side-play amount T_f, calculate described second action time T₀ For: T₀=T_s-(T_max+T_f).Therefore, described switch periods T can finally be calculated_sIn non-straight-through zero state the Two action time T₀For: T₀=T_s-T_max-T_sh+T_min。

S104: according to described switch periods, described pulse width, described first action time and described second Synthesize three-phase pulse bandwidth modulation signals, wherein, described pass-through state ST and described non-straight-through zero action time State lays respectively at crest and the wave trough position of carrier wave.

The pulse width of described threephase switch pipe adds same side-play amount T_fEffective status can't be changed Action time, therefore, exchange output will not be produced impact.For convenience of description, the embodiment of the present invention is with As a example by one sector, i.e. effective status is V₄(100)、V₆(110), it is not added with side-play amount T_fBefore, effective shape State V₄(100) T action time₁' it is: T₁'=T_max-T_mid, effective status V₆(110) T action time₂' it is: T₂'=T_mid-T_min.Add side-play amount T_fRear effective status V₄(100) T action time₁For: T₁=(T_max+T_f)-(T_mid+T_f)=T_max-T_mid, effective status V₆(110) T action time₂For: T₂=(T_mid+T_f)-(T_min+T_f)=T_mid-T_min.It can be seen that add side-play amount T_fRear effective status V₄(100) With effective status V₆(110) keep action time constant.

Therefore, the pulse width of described threephase switch pipe adds same side-play amount T_fAfter, obtain three-phase PWM Pulse width T of signal_ga、T_gb、T_gcIt is respectively as follows:

$\left\{\begin{array}{c}{T}_{ga}=T_{as}+T_f\\ T_{gb}=T_{bs}+T_f\\ T_{gc}=T_{cs}+T_f\end{array}\right.$

Wherein, side-play amount T_fDifference, corresponding different PWM control method, therefore, to side-play amount T_f's Value is critically important.In existing regular sampling, haveIn existing space vector fast algorithm,

In embodiments of the present invention, according to described first action time T_shWith described minima T_minDetermine side-play amount T_f, choose side-play amount T_f=T_sh-T_min, choose this value, it is ensured that non-straight-through zero state and pass-through state ST Laying respectively at summit B and the valley point location A of carrier wave, the most non-straight-through zero state and pass-through state ST are by effectively State isolation is opened, and in a switch periods, pass-through state ST only occurs 1 time, in a switch periods also only There is a non-straight-through zero state, i.e. one of them of V0 (000) and V7 (111).Further, according to institute State switch periods T_s, described pulse width T_ga、T_gb、T_gc, described first action time T_shMake with described second Use time T₀Can synthesize three-phase pulse bandwidth modulation signals, wherein, described pass-through state ST and described non-straight Logical zero state lays respectively at crest and the wave trough position of carrier wave, as shown in Figure 4.

Relatively described non-straight-through zero state second action time T₀With zero size, if T₀>=0, then according to institute State side-play amount T_fPulse width T with threephase switch pipe_as、T_bs、T_csObtain three-phase pulse bandwidth modulation signals Pulse width T_ga、T_gb、T_gcIt is respectively as follows:

$\left\{\begin{array}{c}{T}_{ga}=T_{as}+T_f\\ T_{gb}=T_{bs}+T_f\\ T_{gc}=T_{cs}+T_f\end{array}\right.$

I.e.

$\left\{\begin{array}{c}{T}_{ga}=T_{as}+T_{sh}-T_{min}\\ T_{gb}=T_{bs}+T_{sh}-T_{min}\\ T_{gc}=T_{cs}+T_{sh}-T_{min}\end{array}\right.$

Accordingly, if T₀＜ 0, illustrates that all of zero state time is substituted not enough by pass-through state, then pressed Modulation principle is according to described switch periods T_s, first action time T_shPulse width with described threephase switch pipe T_as、T_bs、T_csSynthesis three-phase pulse bandwidth modulation signals, it is thus achieved that the pulse width of three-phase pulse bandwidth modulation signals Degree T_ga、T_gb、T_gcIt is respectively as follows:

$\left\{\begin{array}{c}{T}_{ga}=\frac{T_s-T_{sh}}{T_{\max }-T_{\min }}(T_{as}-T_{\min })\\ T_{gb}=\frac{T_s-T_{sh}}{T_{\max }-T_{\min }}(T_{bs}-T_{\min })\\ T_{gc}=\frac{T_s-T_{sh}}{T_{\max }-T_{\min }}(T_{cs}-T_{\min })\end{array}\right.$

As a example by first sector, can obtain the order of the on off state change in switch periods Ts is: V₀(000)、 V₄(100)、V₆(110), pass-through state ST, V₆(110)、V₄(100)、V₀, or be (000): V₇(111)、V₆(110)、V₄(100), pass-through state ST, V₄(100)、V₆(110)、V₇(111), Correspondingly, the control method of other each sector is identical.

As a kind of possible embodiment, the method also includes:

S105: at the effect instance sample DC bus-bar voltage of described non-straight-through zero state, it is thus achieved that dc bus Crest voltage.

Owing to pass-through state ST and non-straight-through zero state lay respectively at summit and the position, valley point of carrier wave, the most straight-through Separated by effective status between state ST and non-straight-through zero state, and in a switch periods, pass-through state only goes out The most once, seeing Fig. 4, Fig. 4 is a kind of state vector schematic diagram that the embodiment of the present invention provides.Can from figure To find out, the on off state change order in switch periods Ts is: V₀(000)、V₄(100)、V₆(110)、 Pass-through state ST, V₆(110)、V₄(100)、V₀(000).In applying due to reality, straight-through dutycycle is all Limited (generally less than 30%, i.e. the action time of pass-through state ST is shorter), therefore, pass-through state ST Only concentrate on one of them position in the crest B or trough A of carrier wave, it is assumed that at the trough A of carrier wave, then Pass-through state ST concentrates on the position less than 30% centered by trough A.And in other positions of 70% Corresponding is all non-pass-through state, then, has the abundant time to sample and obtains bus crest voltage.Excellent Choosing, digital signal processor (DSP, Digital Signal Processor) can be very easily at triangular wave Crest B or trough A arrange and interrupt, thus when in this place dc bus being sampled, directly To bus crest voltage.

Implement the embodiment of the present invention, by removing one of them non-straight-through zero state, by whole pass-through state ST Inserting the active position of this non-straight-through zero state, meanwhile, the action time of this non-straight-through zero state is loaded onto separately On the action time of one non-straight-through zero state so that in a switch periods, pass-through state ST only occurs 1 time, Non-straight-through zero state also only one of which.Non-straight-through zero state and pass-through state ST mono-are positioned at crest, another It is positioned at trough, thus DC bus-bar voltage of can sampling within the action time of pass-through state ST easily, directly Measure the crest voltage on dc bus in Z-source inverter, and then can directly busbar voltage be controlled.

See Fig. 5, be the structural representation of a kind of pulse width modulation control device of the embodiment of the present invention, In the embodiment of the present invention, this PWM controls device and includes: first acquisition module the 10, second acquisition module 20, 3rd acquisition module 30 and synthesis module 40.

First acquisition module 10, is used for obtaining switch periods T_sThe pulse width of interior threephase switch pipe, respectively table It is shown as T_as、T_bs、T_cs。

Concrete, according to the voltage V of A, B, C three-phase voltage_a、V_b、V_c, expectation electricity on dc bus Pressure V_DCWith switch periods T_s, it is thus achieved that pulse width T of described threephase switch pipe_as、T_bs、T_csIt is respectively as follows:

$\left\{\begin{array}{c}{T}_{as}=\frac{V_a}{V_{DC}}\·T_s\\ T_{bs}=\frac{V_b}{V_{DC}}\·T_s\\ T_{cs}=\frac{V_c}{V_{DC}}\·T_s\end{array}\right.$

Wherein, the expectation voltage V on dc bus_DCExpectation crest voltage for dc bus.

Second acquisition module, for obtain pass-through state ST in described switch periods first action time T_sh。

When inverter bridge is in pass-through state ST, the switching tube in inverter bridge upper and lower bridge arm simultaneously turns on, quite In dc bus short circuit, now, input power is charged to the electric capacity of Z source network, ac output end Voltage is 0.During pass-through state ST, the capacitance energy storage of Z source network makes the direct current under non-pass-through state female The voltage peak of line increases.Concrete, pass-through state ST first action time T_shCan enter according to actual needs Row arrange, the embodiment of the present invention to first action time T_shValue do not limit.

3rd acquisition module 30, for according to described pulse width and described first action time, obtains described In switch periods non-straight-through zero state second action time T₀。

The non-pass-through state of Z-source inverter include 6 effective status V1 (001), V2 (010), V3 (011), V4 (100), V5 (101), V6 (110) and 2 zero states V₀(000)、V₇(111), at traditional PWM In control method, in a switch periods, include 2 effective statuses, 2 non-straight-through zero states and pass-through state ST.Wherein, non-straight-through zero state inserts crest and the trough of carrier wave respectively, and pass-through state ST is inserted respectively Enter to be positioned in the non-straight-through zero state of crest and wave trough position (as shown in Figure 2), in fig. 2, effective status For V4 (100) and V6 (110), the state of the threephase switch pipe in a switch periods is changed to: pass-through state ST-> zero state 000-> effective status 100-> effective status 110-> zero state 111-> pass-through state ST-> zero shape State 111-> effective status 110-> effective status 100-> zero state 000-> pass-through state ST.Visible open at one In the cycle of pass, pass-through state ST occurs 2 times, owing to carrier frequency is the highest, therefore, causes dc bus Voltage is difficult to acquisition of directly sampling.

In the PWM control method of the embodiment of the present invention, remove one of them non-straight-through zero state, by whole Pass-through state ST inserts the active position of this non-straight-through zero state, meanwhile, during the effect of this non-straight-through zero state Between be loaded onto on the action time of another non-straight-through zero state.Such as: the situation in Fig. 2 uses the present invention After method, the on off state of the threephase switch pipe in switch periods is changed to: zero state 000-> effective status 100-> effective status 110-> pass-through state ST-> effective status 110-> effective status 100-> zero state 000 (as Shown in Fig. 4, Fig. 4 is a kind of state vector schematic diagram that the embodiment of the present invention provides).It can be seen that it is straight-through State ST is only present in the wave trough position of carrier wave, and non-straight-through zero state is only present in the crest location of carrier wave.Class As, pass-through state ST may be located at crest location, rather than straight-through zero state can be located at wave trough position, this Bright without limitation.Sum it up, in the PWM control method that the present invention provides, a switch periods Middle pass-through state ST only occurs 1 time, and at crest B or the trough location A of carrier wave, non-straight-through zero state is also Only one of which, at trough A or the crest B location of carrier wave, non-straight-through zero state is with pass-through state ST respectively Occupying crest and the wave trough position of carrier wave, i.e. one is positioned at crest, and another is positioned at trough.

Preferably, the 3rd acquisition module 30 includes again: comparing unit 301, choose unit 302 and calculate mould Block 303, as shown in Figure 6, Fig. 6 is the structural representation of a kind of 3rd acquisition module in Fig. 5.The most single Unit 301, for pulse width T of relatively described threephase switch pipe_as、T_bs、T_csSize, it is thus achieved that maximum of T_max、 Minima T_minWith intermediate value T_mid, i.e. T_min≤T_mid≤T_max.Such as: in first sector, have T_min=T_cs, T_mid=T_bs, T_max=T_as.Choose unit 302, for according to described first action time T_shWith described minima T_min Determine side-play amount T_f, T_f=T_sh-T_min.Computing module 303, for according to described switch periods T_s, described It is worth greatly T_maxWith described side-play amount T_f, calculate described second action time T₀For: T₀=T_s-(T_max+T_f).Therefore, Finally can calculate described switch periods T_sIn non-straight-through zero state second action time T₀For: T₀=T_s-T_max-T_sh+T_min。

Synthesis module 40, for according to described switch periods, described pulse width, described first action time With synthesize three-phase pulse bandwidth modulation signals, wherein, described pass-through state ST and institute described second action time State non-straight-through zero state and lay respectively at crest and the wave trough position of carrier wave.

The pulse width of described threephase switch pipe adds same side-play amount T_fEffective status can't be changed Action time, therefore, exchange output will not be produced impact.For convenience of description, the embodiment of the present invention is with As a example by one sector, i.e. effective status is V₄(100)、V₆(110), it is not added with side-play amount T_fBefore, effective shape State V₄(100) T action time₁' it is: T₁'=T_max-T_mid, effective status V₆(110) T action time₂' it is: T₂'=T_mid-T_min.Add side-play amount T_fRear effective status V₄(100) T action time₁For: T₁=(T_max+T_f)-(T_mid+T_f)=T_max-T_mid, effective status V₆(110) T action time₂For: T₂=(T_mid+T_f)-(T_min+T_f)=T_mid-T_min.It can be seen that add side-play amount T_fRear effective status V₄(100) With effective status V₆(110) keep action time constant.

Therefore, the pulse width of described threephase switch pipe adds same side-play amount T_fAfter, obtain three-phase PWM Pulse width T of signal_ga、T_gb、T_gcIt is respectively as follows:

$\left\{\begin{array}{c}{T}_{ga}=T_{as}+T_f\\ T_{gb}=T_{bs}+T_f\\ T_{gc}=T_{cs}+T_f\end{array}\right.$

Wherein, side-play amount T_fDifference, corresponding different PWM control method, therefore, to side-play amount T_f's Value is critically important.In existing regular sampling, haveIn existing space vector fast algorithm,

In embodiments of the present invention, according to described first action time T_shWith described minima T_minDetermine side-play amount T_f, choose side-play amount T_f=T_sh-T_min, choose this value, it is ensured that non-straight-through zero state and pass-through state ST Laying respectively at summit B and the valley point location A of carrier wave, the most non-straight-through zero state and pass-through state ST are by effectively State isolation is opened, and in a switch periods, pass-through state ST only occurs 1 time, in a switch periods also only There is a non-straight-through zero state, i.e. one of them of V0 (000) and V7 (111).Further, according to institute State switch periods T_s, described pulse width T_ga、T_gb、T_gc, described first action time T_shMake with described second Use time T₀Can synthesize three-phase pulse bandwidth modulation signals, wherein, described pass-through state ST and described non-straight Logical zero state lays respectively at crest and the wave trough position of carrier wave, as shown in Figure 4.

As a kind of possible embodiment, synthesis module 40 includes again: judging unit 401, first synthesizes Unit 402 and the second synthesis unit 402, see the structure that Fig. 7, Fig. 7 are a kind of synthesis modules in Fig. 5 Schematic diagram.Wherein, it is judged that unit 401, for relatively more described second action time T₀With zero size.First Synthesis unit 402, if for T₀>=0, according to described side-play amount T_fPulse width with described threephase switch pipe T_as、T_bs、T_csSynthesis three-phase pulse bandwidth modulation signals, wherein, described three-phase pulse bandwidth modulation signals Pulse width T_ga、T_gb、T_gcIt is respectively as follows:

$\left\{\begin{array}{c}{T}_{ga}=T_{as}+T_f\\ T_{gb}=T_{bs}+T_f\\ T_{gc}=T_{cs}+T_f\end{array}\right.$

I.e.

$\left\{\begin{array}{c}{T}_{ga}=T_{as}+T_{sh}-T_{min}\\ T_{gb}=T_{bs}+T_{sh}-T_{min}\\ T_{gc}=T_{cs}+T_{sh}-T_{min}\end{array}\right.$

Second synthesis unit 402, if for T₀＜ 0, illustrates that all of zero state time is substituted by pass-through state Not enough, then ovennodulation principle is pressed according to described switch periods T_s, first action time T_shOpen with described three-phase Close pulse width T of pipe_as、T_bs、T_csSynthesis three-phase pulse bandwidth modulation signals, wherein, described three-phase pulse Pulse width T of bandwidth modulation signals_ga、T_gb、T_gcIt is respectively as follows:

$\left\{\begin{array}{c}{T}_{ga}=\frac{T_s-T_{sh}}{T_{\max }-T_{\min }}(T_{as}-T_{\min })\\ T_{gb}=\frac{T_s-T_{sh}}{T_{\max }-T_{\min }}(T_{bs}-T_{\min })\\ T_{gc}=\frac{T_s-T_{sh}}{T_{\max }-T_{\min }}(T_{cs}-T_{\min })\end{array}\right.$

As a example by first sector, can obtain the order of the on off state change in switch periods Ts is: V₀(000)、 V₄(100)、V₆(110), pass-through state ST, V₆(110)、V₄(100)、V₀, or be (000): V₇(111)、V₆(110)、V₄(100), pass-through state ST, V₄(100)、V₆(110)、V₇(111), Correspondingly, the control method of other each sector is identical.

As a kind of possible embodiment, this device also includes sampling module 50, for described non-straight-through The effect instance sample DC bus-bar voltage of zero state, it is thus achieved that dc bus crest voltage.

Owing to pass-through state ST and non-straight-through zero state lay respectively at summit and the position, valley point of carrier wave, the most straight-through Separated by effective status between state ST and non-straight-through zero state, and in a switch periods, pass-through state only goes out The most once, seeing Fig. 4, Fig. 4 is a kind of state vector schematic diagram that the embodiment of the present invention provides.Can from figure To find out, the on off state change order in switch periods Ts is: V₀(000)、V₄(100)、V₆(110)、 Pass-through state ST, V₆(110)、V₄(100)、V₀(000).In applying due to reality, straight-through dutycycle is all Limited (generally less than 30%, i.e. the action time of pass-through state ST is shorter), therefore, pass-through state ST Only concentrate on one of them position in the crest B or trough A of carrier wave, it is assumed that at the trough A of carrier wave, then Pass-through state ST concentrates on the position less than 30% centered by trough A.And in other positions of 70% Corresponding is all non-pass-through state, then, has the abundant time to sample and obtains bus crest voltage.Excellent Choosing, digital signal processor (DSP, Digital Signal Processor) can be very easily at triangular wave Crest B or trough A arrange and interrupt, thus when in this place dc bus being sampled, directly To bus crest voltage.

Implement the embodiment of the present invention, by removing one of them non-straight-through zero state, by whole pass-through state ST Inserting the active position of this non-straight-through zero state, meanwhile, the action time of this non-straight-through zero state is loaded onto separately On the action time of one non-straight-through zero state so that in a switch periods, pass-through state ST only occurs 1 time, Non-straight-through zero state also only one of which.Non-straight-through zero state and pass-through state ST mono-are positioned at crest, another It is positioned at trough, thus DC bus-bar voltage of can sampling within the action time of pass-through state ST easily, directly Measure the crest voltage on dc bus in Z-source inverter, and then can directly busbar voltage be controlled.

One of ordinary skill in the art will appreciate that all or part of flow process realizing in above-described embodiment method, Can be by computer program and complete to instruct relevant hardware, described program can be stored in a calculating In machine read/write memory medium, this program is upon execution, it may include such as the flow process of the embodiment of above-mentioned each method. Wherein, described storage medium can be magnetic disc, CD, read-only store-memory body (Read-Only Memory, Or random store-memory body (RandomAccess Memory, RAM) etc. ROM).

Above disclosed only one preferred embodiment of the present invention, can not limit this with this certainly Bright interest field, one of ordinary skill in the art will appreciate that all or part of stream realizing above-described embodiment Journey, and according to the equivalent variations that the claims in the present invention are made, still fall within the scope that invention is contained.

Claims (10)

1. a pulse width modulation control method, it is characterised in that including:

Obtain switch periods T_sThe pulse width of interior threephase switch pipe, is expressed as T_as、T_bs、T_cs；

Obtain pass-through state ST in described switch periods first action time T_sh；

According to described pulse width and described first action time, in obtaining described switch periods non-straight-through zero state second action time T₀；

Three-phase pulse bandwidth modulation signals is synthesized according to described switch periods, described pulse width, described first action time and described second action time, wherein, described pass-through state ST and described non-straight-through zero state lay respectively at crest and the wave trough position of carrier wave, and the pulse width of described three-phase pulse bandwidth modulation signals is expressed as T_ga、T_gb、T_gc；

As a example by first sector, the on off state change order in switch periods Ts is: V₀(000)、V₄(100)、V₆(110), pass-through state ST, V₆(110)、V₄(100)、V₀(000), or: V₇(111)、V₆(110)、V₄(100), pass-through state ST, V₄(100)、V₆(110)、V₇(111)。

2. the method for claim 1, it is characterised in that described according to described pulse width with described first action time, in obtaining described switch periods non-straight-through zero state second action time T₀, including:

Relatively pulse width T of described threephase switch pipe_as、T_bs、T_csSize, it is thus achieved that maximum of T_max, minima T_minWith intermediate value T_mid, i.e. T_min≤T_mid≤T_max；

According to described first action time T_shWith described minima T_minDetermine side-play amount T_f, T_f=T_sh-T_min；

According to described switch periods T_s, described maximum of T_maxWith described side-play amount T_f, calculate described second action time T₀For: T₀=T_s-(T_max+T_f)。

3. method as claimed in claim 2, it is characterised in that described according to described switch periods, described pulse width, described first action time and described second action time synthesizing three-phase pulse bandwidth modulation signals, including:

Relatively more described second action time T₀With zero size；

If T₀>=0, according to described side-play amount T_fPulse width T with described threephase switch pipe_as、T_bs、T_csSynthesis three-phase pulse bandwidth modulation signals, wherein, pulse width T of described three-phase pulse bandwidth modulation signals_ga、T_gb、T_gcIt is respectively as follows:

If T₀＜ 0, according to described switch periods T_s, first action time T_shPulse width T with described threephase switch pipe_as、T_bs、T_csSynthesis three-phase pulse bandwidth modulation signals, wherein, pulse width T of described three-phase pulse bandwidth modulation signals_ga、T_gb、T_gcIt is respectively as follows:

4. method as claimed in claim 3, it is characterised in that described acquisition switch periods T_sThe pulse width of interior threephase switch pipe, including:

Voltage V according to A, B, C three-phase voltage_a、V_b、V_c, expectation voltage V on dc bus_DCWith switch periods T_s, it is thus achieved that pulse width T of described threephase switch pipe_as、T_bs、T_csIt is respectively as follows:

5. the method as described in any one of claim 1-4, it is characterised in that also include:

Within the action time of described non-straight-through zero state, DC bus-bar voltage is sampled, it is thus achieved that dc bus crest voltage.

6. a pulse width modulation controls device, it is characterised in that including:

First acquisition module, is used for obtaining switch periods T_sThe pulse width of interior threephase switch pipe, is expressed as T_as、T_bs、T_cs；

Second acquisition module, for obtain pass-through state ST in described switch periods first action time T_sh；

3rd acquisition module, for according to described pulse width and described first action time, in obtaining described switch periods non-straight-through zero state second action time T₀；

Synthesis module, for according to described switch periods, described pulse width, described first action time and described second action time synthesizing three-phase pulse bandwidth modulation signals, wherein, described pass-through state ST and described non-straight-through zero state lay respectively at crest and the wave trough position of carrier wave, and the pulse width of described three-phase pulse bandwidth modulation signals is expressed as T_ga、T_gb、T_gc；

As a example by first sector, the on off state change order in switch periods Ts is: V₀(000)、V₄(100)、V₆(110), pass-through state ST, V₆(110)、V₄(100)、V₀(000), or be: V₇(111)、V₆(110)、V₄(100), pass-through state ST, V₄(100)、V₆(110)、V₇(111)。

7. device as claimed in claim 6, it is characterised in that described 3rd acquisition module includes:

Comparing unit, for pulse width T of relatively described threephase switch pipe_as、T_bs、T_csSize, it is thus achieved that maximum of T_max, minima T_minWith intermediate value T_mid, i.e. T_min≤T_mid≤T_max；

Choose unit, for according to described first action time T_shWith described minima T_minDetermine side-play amount T_f, T_f=T_sh-T_min；

Computing unit, for according to described switch periods T_s, described maximum of T_maxWith described side-play amount T_f, calculate described second action time T₀For: T₀=T_s-(T_max+T_f)。

8. device as claimed in claim 7, it is characterised in that described synthesis module includes:

Judging unit, for relatively more described second action time T₀With zero size；

First synthesis unit, if for T₀>=0, according to described side-play amount T_fPulse width T with described threephase switch pipe_as、T_bs、T_csSynthesis three-phase pulse bandwidth modulation signals, wherein, pulse width T of described three-phase pulse bandwidth modulation signals_ga、T_gb、T_gcIt is respectively as follows:

Second synthesis unit, if for T₀＜ 0, according to described switch periods T_s, first action time T_shPulse width T with described threephase switch pipe_as、T_bs、T_csSynthesis three-phase pulse bandwidth modulation signals, wherein, pulse width T of described three-phase pulse bandwidth modulation signals_ga、T_gb、T_gcIt is respectively as follows:

9. device as claimed in claim 8, it is characterised in that described first acquisition module is for the voltage V according to A, B, C three-phase voltage_a、V_b、V_c, expectation voltage V on dc bus_DCWith switch periods T_s, it is thus achieved that pulse width T of described threephase switch pipe_as、T_bs、T_csIt is respectively as follows:

10. the device as described in any one of claim 6-9, it is characterised in that also include:

Sampling module, for sampling to DC bus-bar voltage, it is thus achieved that dc bus crest voltage within the action time of described non-straight-through zero state.