CN104009487A - Method and device for directly controlling power of PWM rectifier under imbalanced network voltages - Google Patents

Abstract

The invention discloses a method for directly controlling the power of a PWM rectifier under imbalanced network voltages. The method includes the steps that according to sampled network voltages, sampled network currents and network voltage delay signals, the instantaneous active power and the novel reactive power at the current moment are acquired through calculation; a voltage vector table capable of simultaneously controlling the active power and the novel reactive power based on voltage imbalance defined by the novel reactive power is acquired through analysis; an acquired difference value and a sector where a current network voltage vector is located are given through the instantaneous active power, the novel reactive power and the corresponding power; according to the voltage vector table, voltage vectors are selected, and corresponding driving signals are acquired for driving a switching tube. The invention further discloses a device for directly controlling the power adopting the method for directly controlling the power of the PWM rectifier. According to the method and device for directly controlling the power of the PWM rectifier, conversion of rotational coordinates is not needed, the calculated amount is small, implementation is easy, and robustness is good.

Description

PWM rectifier direct Power Control method and device under unbalanced electric grid voltage

Technical field

The present invention relates to electric and electronic technical field, refer to especially PWM rectifier direct Power Control method and device under a kind of unbalanced electric grid voltage.

Background technology

Direct Power Control, without Rotating Transition of Coordinate, has the advantages such as algorithm is simple, dynamic response is fast and is widely accepted.And direct Power Control has comparatively deep research under desirable electrical network, but in actual electric network because the factor such as laod unbalance and electric network fault all can cause that line voltage is asymmetric; Can make current on line side occur a large amount of harmonic waves if continue to use the method for traditional direct Power Control, there are two frequency multiplication fluctuations etc. in DC bus-bar voltage and net side power, has a strong impact on the performance of system.Countries in the world scholar has done relevant research for the direct Power Control under unbalanced power supply condition for this reason, to realizing constant DC voltage output, reduces current on line side harmonic wave and meritorious or reactive power fluctuation.

In existing method, document " Direct power control of voltage source inverters with unbalanced grid voltages " draws the power compensating value of eliminating negative phase-sequence current on line side by derivation, then this offset is joined to original value and power reference, obtain the new value and power reference in unbalanced source voltage situation.This scheme is easy to be integrated in existing DPC and uses, and its weak point is that the acquisition of power compensating value need to be carried out positive-negative sequence decomposition and Rotating Transition of Coordinate to line voltage and electric current, calculates relative complex.Document " Sliding-mode-based direct power control of grid-connected voltage-sourced inverters under unbalanced network conditions " improves on the basis of " Direct power control of voltage source inverters with unbalanced grid voltages ", drawn the power compensating value under different control targets by derivation in rest frame, and adopt sliding formwork control and SVM to improve robustness and the steady-state behaviour of system, but the calculating of offset still needs the extraction of line voltage negative sequence component and electric current positive sequence component, sliding mode controller need to regulate the parameters such as sliding formwork gain in addition.

Direct Power Control based in unbalanced source voltage situation does not have to meet simultaneously at present: 1) needs do not extract positive-negative sequence component; 2) do not need rated output offset.Therefore, need to develop a kind of simple and effective direct Power Control; This simple direct Power Control does not need to extract positive-negative sequence component does not need complicated power back-off to calculate simultaneously, and can eliminate the impact that unbalance voltage is brought, thereby raising system, to the adaptability in uneven electrical network situation, meets actual motion demand.

Summary of the invention

In view of this, the object of the invention is to propose PWM rectifier direct Power Control method and device under a kind of unbalanced electric grid voltage, by the method for existing PWM rectifier direct Power Control is improved, a kind of novel direct Power Control is proposed, thereby can strengthen the adaptability to unbalanced source voltage, comprise the two frequencys multiplication fluctuations of eliminating net survey active power, eliminate two frequency multiplication fluctuations of novel reactive power, the pulsation of elimination VD, reduce the harmonic wave of current on line side, reach with balance electrical network under similar operational effect.

Based on PWM rectifier direct Power Control method under above-mentioned purpose unbalanced electric grid voltage provided by the invention, comprising:

According to sampling line voltage and power network current and line voltage inhibit signal, calculate instantaneous active power and the novel reactive power of current time;

Obtaining can simultaneously control under the Voltage unbalance based on novel reactive power definition by analysis gains merit and novel idle voltage vector table;

The difference and the sector, current line voltage vector place that are obtained by instantaneous active power, novel reactive power and corresponding power given;

Select voltage vector according to described voltage vector table, driven accordingly signal to drive switching tube.

In some embodiments, described according to sampling line voltage and power network current and line voltage inhibit signal, calculate the instantaneous active power of current time and the step of novel reactive power comprises:

Utilize voltage LEM transducer and electric current LEM sensor sample rectifier DC side voltage, grid side voltage and power network current;

Then grid side voltage is obtained to voltage signal and the current signal on static two phase coordinates α β by 3/2 conversion;

Voltage vector and DC voltage by a upper moment calculate rectifier AC voltage signal;

1/4 week after date of grid side voltage delay is obtained to its inhibit signal;

The computing formula of described active power is: P=1.5 (i _αe _α+ i _βe _β); Wherein, i _α, i _βfor the current signal on static two phase coordinates α β, e _α, e _βfor the voltage signal on static two phase coordinates α β;

The computing formula of described rectifier AC voltage signal is:

$v=\frac{2}{3}{U}_{\mathrm{dc}}(S_a+a{S}_b+a^2{S}_c)$

$a=e^{j\frac{2}{3}\mathrm{\π}}$

v _α＝Re(v),v _β＝Im(v)

Wherein: S _a, S _b, S _crepresent the on off state of switching tube;

The computing formula of described novel Reactive power definition is: Q ^nov=1.5 (i _αe _α'+i _βe _β'); Wherein, i _α, i _βfor the current signal on static two phase coordinates α β, e _α', e _β' inhibit signal for 1/4 week after date of grid side voltage delay is obtained.

In some embodiments, the described step that can simultaneously control meritorious and novel idle voltage vector table obtaining under the Voltage unbalance based on novel reactive power definition by analysis comprises:

The computing formula of calculating the rate of change of active power rate of change in uneven situation and novel reactive power is respectively:

$\frac{\mathrm{dP}}{\mathrm{dt}}=\frac{3}{2L}({e_{\mathrm{\α}}}^2+{e_{\mathrm{\β}}}^2-(v_{\mathrm{\α}}{e}_{\mathrm{\α}}+v_{\mathrm{\β}}{e}_{\mathrm{\β}}))-\frac{R}{L}P-\mathrm{\ω}{Q}^{\mathrm{nov}},$

$\frac{d{Q}^{\mathrm{nov}}}{\mathrm{dt}}=\frac{3}{2L}(e_{\mathrm{\α}}{e}_{\mathrm{\α}}^{\′}+e_{\mathrm{\β}}{e}_{\mathrm{\β}}^{\′}-(v_{\mathrm{\α}}{e}_{\mathrm{\α}}^{\′}+v_{\mathrm{\β}}{e}_{\mathrm{\β}}^{\′}))-\frac{R}{L}{Q}^{\mathrm{nov}}+\mathrm{\ωP},$

Drawn the gain merit/novel idle change rate curve of different voltage vectors by active power rate of change and novel reactive power rate of change;

By power variation rate curve corresponding to different voltage vectors, derive under the unbalanced source voltage based on novel reactive power definition and can control meritorious and novel idle voltage vector table simultaneously.

In some embodiments, described employing based on can control under novel Reactive power definition to gain merit simultaneously with novel idle voltage vector table is:

Δp	Δq	Sector k
			Increase	Increase	V 0V 7V k+2V k+3
Increase	Reduce	V k-2V k-1

Reduce	Increase	V k+1
			Reduce	Reduce	V k

In some embodiments, described control method also comprises:

The difference of given direct voltage and PWM rectifier DC side voltage is passed through pi regulator and is multiplied by DC voltage and obtains the initial set-point of active power; The initial set-point of reactive power is made as zero;

By the instantaneous power of current time and the difference of power given and sector, line voltage vector place, select voltage vector according to the voltage vector table obtaining, driven accordingly signal to drive switching tube.

The present invention also provides a kind of PWM rectifier direct Power Control device of the direct Power Control method that adopts PWM rectifier under described unbalanced electric grid voltage, comprises the three-phase voltage source, three-phase filter inductance, rectifier bridge main circuit, DC bus capacitor, the load that connect successively; And, carry out respectively the electric current and voltage sample circuit of voltage, current sample from three-phase voltage source output terminal and three-phase filter inductance output, the electric current and voltage data of electric current and voltage sample circuit are carried out to the dsp controller of s operation control, drive circuit;

Wherein, described electric current and voltage sample circuit utilizes voltage hall sensor and current Hall transducer to gather respectively three-phase net side alternating voltage, alternating current and rectifier DC side voltage, enters dsp controller and be converted to digital signal after signal conditioning circuit; Dsp controller completes the computing of the direct Power Control method of PWM rectifier under described unbalanced electric grid voltage, exports six road pwm pulses, then after overdrive circuit, obtains the final driving signal of six switching tubes of rectifier.

As can be seen from above, direct Power Control method and the device of PWM rectifier under unbalanced electric grid voltage provided by the invention, by error and the sector, line voltage place of instantaneous power and given power, the voltage vector table of looking under novel Reactive power definition obtains corresponding voltage vector, thereby obtains driving signal to drive switching tube; Have without rotating coordinate transformation, the feature such as little, the easy realization of amount of calculation, robustness are good can reduce the harmonic distortion of current on line side in eliminating DC voltage ripple.

Brief description of the drawings

Fig. 1 is the schematic flow sheet of an embodiment of the direct Power Control method of PWM rectifier under unbalanced electric grid voltage provided by the invention;

Fig. 2 is the structural representation of an embodiment of the direct Power Control device of PWM rectifier under unbalanced electric grid voltage provided by the invention;

Fig. 3 is the structural representation of another embodiment of the direct Power Control device of PWM rectifier under unbalanced electric grid voltage provided by the invention;

Fig. 4 is the change rate curve schematic diagram of active power and the novel reactive power of different voltage vectors;

Fig. 5 is active power, the traditional reactive power of traditional direct Power Control under unbalanced source voltage, novel reactive power, the simulation result schematic diagram of voltage on line side, electric current;

Fig. 6 is active power, the traditional reactive power of direct Power Control method under unbalanced source voltage that adopts the present invention to propose, novel reactive power, the simulation result schematic diagram of voltage on line side, electric current;

Fig. 7 adopts traditional direct Power Control to equilibrate to the active power in uneven situation by line voltage, novel reactive power, the experimental result schematic diagram of voltage on line side, electric current;

Fig. 8 is that the direct Power Control method that adopts the present invention to propose equilibrates to the active power in uneven situation by line voltage, novel reactive power, the experimental result schematic diagram of voltage on line side, electric current.

Embodiment

For making the object, technical solutions and advantages of the present invention clearer, below in conjunction with specific embodiment, and with reference to accompanying drawing, the present invention is described in more detail.

With reference to accompanying drawing 1, it is the schematic flow sheet of an embodiment of the direct Power Control method of PWM rectifier under unbalanced electric grid voltage provided by the invention.

The direct Power Control method of PWM rectifier under described unbalanced electric grid voltage, comprising:

Step 101: according to sampling line voltage and power network current and line voltage inhibit signal, calculate instantaneous active power and the novel reactive power of current time;

Step 102: obtain can simultaneously control under the Voltage unbalance based on novel reactive power definition by analysis and gain merit and novel idle voltage vector table;

Step 103: the difference and the sector, current line voltage vector place that are obtained by instantaneous active power, novel reactive power and corresponding power given;

Step 104: select voltage vector according to described voltage vector table, driven accordingly signal to drive switching tube.

With reference to accompanying drawing 2, it is the structural representation of an embodiment of the direct Power Control device of PWM rectifier under unbalanced electric grid voltage provided by the invention.

Adopt the direct Power Control device of the PWM rectifier of the direct Power Control method of PWM rectifier under above-mentioned unbalanced electric grid voltage, comprise the three-phase voltage source, three-phase filter inductance (in figure, R is equivalent resistance), rectifier bridge main circuit, DC bus capacitor, the load that connect successively; And, carry out respectively the electric current and voltage sample circuit of voltage, current sample from three-phase voltage source output terminal and three-phase filter inductance output, the electric current and voltage data of electric current and voltage sample circuit are carried out to the dsp controller of s operation control, drive circuit;

Wherein, described electric current and voltage sample circuit utilizes voltage hall sensor and current Hall transducer to gather respectively three-phase net side alternating voltage, alternating current and rectifier DC side voltage, enters dsp controller and be converted to digital signal after signal conditioning circuit; Dsp controller completes the computing of the direct Power Control method of PWM rectifier under described unbalanced electric grid voltage, exports six road pwm pulses, then after overdrive circuit, obtains the final driving signal of six switching tubes of rectifier.

Under the described unbalanced electric grid voltage based on novel Reactive power definition, the direct Power Control method of PWM rectifier also comprises another kind of execution mode, and its step comprises:

Grid side voltage obtains the voltage signal e on static two-phase α β coordinate by 3/2 conversion _α, e _βand current signal i _α, i _β; Further obtain grid side voltage delay signal e by 1/4 cycle delay function _α', e _β'; Rectifier AC voltage signal ν _α, ν _βvoltage vector and DC voltage by a upper moment calculate;

The inhibit signal of the grid side voltage obtaining according to above-mentioned steps and grid side current signal and grid side voltage, can analytical Calculation obtains the instantaneous value of current time active power and novel reactive power;

Calculate the rate of change of active power and the rate of change of novel reactive power in unbalanced source voltage situation, and draw the change rate curve of the active power/novel reactive power of different voltage vectors; Derive in the unbalanced source voltage situation based on novel Reactive power definition and can control meritorious and novel idle voltage vector table simultaneously;

Given direct voltage is deducted to the error signal that PWM rectifier output dc voltage obtains and enter pi regulator, the output of pi regulator is multiplied by PWM rectifier DC side voltage and is obtained the given P of initial active power ^ref; The initial given Q of reactive power ^refbe made as zero;

The voltage vector table obtaining is inquired about in the power instruction obtaining according to previous step and difference and the sector, the current place of line voltage of instantaneous power, thereby select voltage vector by inquiry voltage vector table, the switching signal corresponding by this voltage vector drives switching tube.

As can be seen from above, PWM rectifier direct Power Control method and device under unbalanced electric grid voltage provided by the invention, by error and the sector, line voltage place of instantaneous power and given power, the voltage vector table of looking under novel Reactive power definition obtains corresponding voltage vector, thereby obtains driving signal to drive switching tube; Have without rotating coordinate transformation, the feature such as little, the easy realization of amount of calculation, robustness are good can reduce the harmonic distortion of current on line side in eliminating DC voltage ripple.

Further, with reference to accompanying drawing 3, be the structural representation of another embodiment of the direct Power Control device of PWM rectifier under unbalanced electric grid voltage provided by the invention; Comprising the concrete calculation step of dsp controller described in Fig. 2; That is described direct Power Control method realizes successively in accordance with the following steps on the dsp controller of Fig. 2:

Step 1: three phase network side voltage and current obtains the voltage signal e on static two-phase α β coordinate by 3/2 conversion _α, e _βwith current signal i _α, i _β, be specifically expressed as:

$\left[\begin{array}{c}{e}_{\mathrm{\α}}\\ e_{\mathrm{\β}}\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{e}_a\\ e_b\\ e_c\end{array}\right]$

$\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{i}_a\\ i_b\\ i_c\end{array}\right]$

E _α, e _βfurther obtain e by postponing for 1/4 cycle _α', e _β', be specifically expressed as:

$e_{\mathrm{\α}}^{\′}\left(t\right)=e_{\mathrm{\α}}(t-\frac{T}{4})$

$e_{\mathrm{\β}}^{\′}\left(t\right)=e_{\mathrm{\β}}(t-\frac{T}{4})$

Wherein T is a power frequency period, is 0.02s for 50Hz electrical network;

ν _α, ν _βspecifically be expressed as:

$v=\frac{2}{3}{U}_{\mathrm{dc}}(S_a+a{S}_b+a^2{S}_c)$

$a=e^{j\frac{2}{3}\mathrm{\π}}$

v _α＝Re(v),v _β＝Im(v)

Wherein: S _a, S _b, S _crepresent the on off state of switching tube.

Step 2: can obtain the instantaneous power of net side by the sample voltage signal, the current signal that obtain and the voltage delay signal obtaining by delay of step 1;

Active power and traditional reactive power are:

$\left[\begin{array}{c}P\\ Q\end{array}\right]=\frac{3}{2}\left[\begin{array}{c}{i}_{\mathrm{\α}}{e}_{\mathrm{\α}}+i_{\mathrm{\β}}{e}_{\mathrm{\β}}\\ i_{\mathrm{\α}}{e}_{\mathrm{\β}}-i_{\mathrm{\β}}{e}_{\mathrm{\α}}\end{array}\right],$

Novel reactive power is:

$Q^{\mathrm{nov}}=\frac{3}{2}\left(i_{\mathrm{\α}}{{e^{\′}}_{\mathrm{\α}}+i}_{\mathrm{\β}}{e^{\′}}_{\mathrm{\β}}\right)$

Step 3: calculate active power rate of change in uneven situation and the rate of change of novel reactive power and be respectively:

$\frac{\mathrm{dP}}{\mathrm{dt}}=\frac{3}{2L}({e_{\mathrm{\α}}}^2+{e_{\mathrm{\β}}}^2-(v_{\mathrm{\α}}{e}_{\mathrm{\α}}+v_{\mathrm{\β}}{e}_{\mathrm{\β}}))-\frac{R}{L}P-\mathrm{\ω}{Q}^{\mathrm{nov}},$

$\frac{d{Q}^{\mathrm{nov}}}{\mathrm{dt}}=\frac{3}{2L}(e_{\mathrm{\α}}{e}_{\mathrm{\α}}^{\′}+e_{\mathrm{\β}}{e}_{\mathrm{\β}}^{\′}-(v_{\mathrm{\α}}{e}_{\mathrm{\α}}^{\′}+v_{\mathrm{\β}}{e}_{\mathrm{\β}}^{\′}))-\frac{R}{L}{Q}^{\mathrm{nov}}+\mathrm{\ωP},$

Can be drawn the gain merit/novel idle change rate curve of different voltage vectors by active power rate of change and novel reactive power rate of change, as shown in Figure 4.By the power variation rate curve of different voltage vectors, can derive the voltage vector table in the unbalanced source voltage situation based on novel Reactive power definition herein, as shown in table 1.

Voltage vector table in the unbalanced source voltage situation of table 1 based on novel Reactive power definition

Δp	Δq	Sector k
			Increase	Increase	V 0V 7V k+2V k+3
Increase	Reduce	V k-2V k-1
			Reduce	Increase	V k+1
Reduce	Reduce	V k

Step 4: given direct voltage with PWM rectifier DC side voltage U _dcdifference through pi regulator be multiplied by U _dcobtaining the initial set-point of active power is P ^ref, be specifically expressed as $P^{\mathrm{ref}}=(k_p+\frac{k_i}{s})(U_{\mathrm{dc}}^{\mathrm{ref}}-U_{\mathrm{dc}})\×U_{\mathrm{dc}}$ (k _pand k _ibe respectively proportional gain and storage gain in pi regulator); The initial set-point Q of reactive power ^refbe made as zero;

Step 5: look into the voltage vector table that step 3 obtains according to the difference of power given value and instantaneous power and sector, voltage on line side place, thereby the voltage vector table selection voltage vector obtaining by looking into step 3, the switching signal corresponding by this voltage vector drives switching tube.

The validity of method proposed by the invention can draw by the simulation result shown in comparison diagram 5 and Fig. 6, the two test condition is identical, difference is only that Fig. 5 is traditional direct Power Control, and Fig. 6 has adopted novel direct Power Control proposed by the invention.In order to further illustrate the validity of put forward the methods of the present invention, the present invention gives experimental result that traditional direct Power Control and novel direct Power Control equilibrate to non-equilibrium process by line voltage as shown in FIG. 7 and 8.In Fig. 5, waveform is followed successively by active power, traditional reactive power from top to bottom, novel reactive power, and voltage on line side, electric current, line voltage starts asymmetric in the time of 0.02s, and also there is distortion in current on line side.After the novel direct Poewr control method that adopts the present invention to carry, the distortion of current on line side is eliminated, and is uneven but sinusoidal waveform, and the reactive power of active power and novel definition does not have two frequency multiplication fluctuations simultaneously.

As can be seen from above, PWM rectifier direct Power Control method and device under unbalanced electric grid voltage provided by the invention, by error and the sector, line voltage place of instantaneous power and given power, the voltage vector table of looking under novel Reactive power definition obtains corresponding voltage vector, thereby obtains driving signal to drive switching tube; Described direct Power Control method and device do not need the extraction of positive-negative sequence component, do not need rated output offset; Have without rotating coordinate transformation, the feature such as little, the easy realization of amount of calculation, robustness are good, easy to implement can reduce the harmonic distortion of current on line side in eliminating DC voltage ripple simultaneously.

Those of ordinary skill in the field are to be understood that: the foregoing is only specific embodiments of the invention; be not limited to the present invention; within the spirit and principles in the present invention all, any amendment of making, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.

Claims (6)

1. a PWM rectifier direct Power Control method under unbalanced electric grid voltage, is characterized in that, comprising:

According to sampling line voltage and power network current and line voltage inhibit signal, calculate instantaneous active power and the novel reactive power of current time;

Obtaining can simultaneously control under the Voltage unbalance based on novel reactive power definition by analysis gains merit and novel idle voltage vector table;

The difference and the sector, current line voltage vector place that are obtained by instantaneous active power, novel reactive power and corresponding power given;

Select voltage vector according to described voltage vector table, driven accordingly signal to drive switching tube.

2. method according to claim 1, is characterized in that, described according to sampling line voltage and power network current and line voltage inhibit signal, calculates the instantaneous active power of current time and the step of novel reactive power comprises:

Utilize voltage LEM transducer and electric current LEM sensor sample rectifier DC side voltage, grid side voltage and power network current;

Then grid side voltage is obtained to voltage signal and the current signal on static two phase coordinates α β by 3/2 conversion;

Voltage vector and DC voltage by a upper moment calculate rectifier AC voltage signal;

1/4 week after date of grid side voltage delay is obtained to its inhibit signal;

The computing formula of described active power is: P=1.5 (i _αe _α+ i _βe _β); Wherein, i _α, i _βfor the current signal on static two phase coordinates α β, e _α, e _βfor the voltage signal on static two phase coordinates α β;

The computing formula of described rectifier AC voltage signal is:

$v=\frac{2}{3}{U}_{\mathrm{dc}}(S_a+a{S}_b+a^2{S}_c)$

$a=e^{j\frac{2}{3}\mathrm{\π}}$

v _α＝Re(v),v _β＝Im(v)

Wherein: S _a, S _b, S _crepresent the on off state of switching tube;

The computing formula of described novel Reactive power definition is: Q ^nov=1.5 (i _αe _α'+i _βe _β'); Wherein, i _α, i _βfor the current signal on static two phase coordinates α β, e _α', e _β' inhibit signal for 1/4 week after date of grid side voltage delay is obtained.

3. method according to claim 2, is characterized in that, the described step that can simultaneously control meritorious and novel idle voltage vector table obtaining under the Voltage unbalance based on novel reactive power definition by analysis comprises:

The computing formula of calculating the rate of change of active power rate of change in uneven situation and novel reactive power is respectively:

$\frac{\mathrm{dP}}{\mathrm{dt}}=\frac{3}{2L}({e_{\mathrm{\α}}}^2+{e_{\mathrm{\β}}}^2-(v_{\mathrm{\α}}{e}_{\mathrm{\α}}+v_{\mathrm{\β}}{e}_{\mathrm{\β}}))-\frac{R}{L}P-\mathrm{\ω}{Q}^{\mathrm{nov}},$

$\frac{d{Q}^{\mathrm{nov}}}{\mathrm{dt}}=\frac{3}{2L}(e_{\mathrm{\α}}{e}_{\mathrm{\α}}^{\′}+e_{\mathrm{\β}}{e}_{\mathrm{\β}}^{\′}-(v_{\mathrm{\α}}{e}_{\mathrm{\α}}^{\′}+v_{\mathrm{\β}}{e}_{\mathrm{\β}}^{\′}))-\frac{R}{L}{Q}^{\mathrm{nov}}+\mathrm{\ωP},$

Drawn the gain merit/novel idle change rate curve of different voltage vectors by active power rate of change and novel reactive power rate of change;

By power variation rate curve corresponding to different voltage vectors, derive under the unbalanced source voltage based on novel reactive power definition and can control meritorious and novel idle voltage vector table simultaneously.

4. method according to claim 3, is characterized in that, described employing based on can control meritorious and novel idle voltage vector table under novel Reactive power definition be simultaneously:

Δp Δq Sector k Increase Increase V ₀V ₇V _k+2V _k+3 Increase Reduce V _k-2V _k-1 Reduce Increase V _k+1 Reduce Reduce V _k

5. method according to claim 1, is characterized in that, described control method also comprises:

The difference of given direct voltage and PWM rectifier DC side voltage is passed through pi regulator and is multiplied by DC voltage and obtains the initial set-point of active power; The initial set-point of reactive power is made as zero;

By the instantaneous power of current time and the difference of power given and sector, line voltage vector place, select voltage vector according to the voltage vector table obtaining, driven accordingly signal to drive switching tube.

6. the PWM rectifier direct Power Control device of PWM rectifier direct Power Control method under the employing unbalanced electric grid voltage as described in claim 1-5 any one, it is characterized in that, comprise the three-phase voltage source, three-phase filter inductance, rectifier bridge main circuit, DC bus capacitor, the load that connect successively; And, carry out respectively the electric current and voltage sample circuit of voltage, current sample from three-phase voltage source output terminal and three-phase filter inductance output, the electric current and voltage data of electric current and voltage sample circuit are carried out to the dsp controller of s operation control, drive circuit;

Wherein, described electric current and voltage sample circuit utilizes voltage hall sensor and current Hall transducer to gather respectively three-phase net side alternating voltage, alternating current and rectifier DC side voltage, enters dsp controller and be converted to digital signal after signal conditioning circuit; Dsp controller completes the computing of PWM rectifier direct Power Control method under the unbalanced electric grid voltage as described in claim 1-5 any one, export six road pwm pulses, then after overdrive circuit, obtain the final driving signal of six switching tubes of rectifier.