CN103944428B - A kind of control method of the Three-Phase PWM Rectifier being applicable to waveform distortion of the power supply network - Google Patents

Abstract

The invention discloses the control method of a kind of Three-Phase PWM Rectifier being applicable to waveform distortion of the power supply network, mainly include the extraction of current reference signal under input voltage distortion and uneven disturbance background, actively inject negative-sequence current and combine the improvement dead beat current inner loop of linear outside forecast；The DC voltage outer shroud of Active Disturbance Rejection Control.Its function is the harmonic wave of suppression PWM rectifier input current, injects suitable negative-sequence current to eliminate 2 power pulsations of PWM rectifier output DC voltage, improve the transient response of output DC voltage and compensate the various delay impact on track with zero error.The present invention can be obviously reduced Three-Phase PWM Rectifier and export 2 ripples of DC voltage under input harmonics and unbalance voltage disturbance, promote the transient response speed of PWM rectifier and reduce DC voltage transient state side-play amount, and improves system control accuracy.

Description

A kind of control method of the Three-Phase PWM Rectifier being applicable to waveform distortion of the power supply network

Technical field

The present invention relates to 3-Phase PWM High Factor Rectifier control field, particularly one, to be applicable to network wave abnormal The control method of the Three-Phase PWM Rectifier become.

Background technology

Along with the development of Power Electronic Technique, PWM rectifier technology reaches its maturity, and PWM rectifier main circuit is from early days Half control type device bridge develop into wholly-controled device bridge of today；Its topological structure develops into from single-phase, three-phase circuit The most combined and many level topological circuit.Owing to conventional rectification link is widely used the uncontrollable rectification circuit of diode or brilliant lock Pipe phase control rectifier circuit, thus electrical network is filled with a large amount of harmonic wave and reactive power, reduce power factor, cause serious Electrical network " pollutes ".Declining problem for solving harmonic wave and power factor, the commutator as main " pollution " source of electrical network is subject to science The concern on boundary, and carry out numerous studies work.PWM rectifier can realize current on line side sine, and runs on unit power Factor, energy two-way transmission, have and the most dynamically control response, thus be truly realized " green energy conversion ".

In the control of high-power factory rectifier, generally use Double closed-loop of voltage and current method, for letter Changing commutator control and be easy to engineer applied, Voltage loop uses PI control method mostly, and the control of electric current loop decision systems is smart Degree and corresponding speed, be the emphasis of research.Currently, the current control method that engineer applied is more mainly includes Hysteresis control, PI The methods such as control, ratio resonance (PR) control, track with zero error.Hysteresis control is simple, and robustness is good, but switching frequency is not solid Fixed, current ripples is big, affects the control accuracy of DC voltage；Conventional PI control design is simple, it is easy to accomplish, but cannot realize Tracing control without steady-state error to of ac；Ratio resonance (PR) controller has infinitely-great gain at the resonant frequency fx, Exchange reference current can be followed the tracks of with zero steady-state error, but when mains frequency offsets, control accuracy will be a greater impact.Nothing Beat control is control algolithm based on controlled device exact circuitry model, has the advantages that corresponding speed is fast, control error is little, So, the dead-beat control method that current inner loop is used.

But, electrical network is it sometimes appear that unbalanced state, once unbalanced power supply, set with three-phase grid balance for constraint The PWM rectifier of meter arises that abnormal running status, is mainly manifested in: PWM rectifier DC voltage and net side electricity The low-order harmonic amplitude of stream increases, and produces uncharacteristic harmonics, and loss simultaneously is corresponding to increase；PWM rectifier current on line side is the most not Balance, can make PWM rectification break down, even burn out device time serious.Therefore, it is necessary to improve the anti-input of PWM rectifier Harmonic wave and three-phase imbalance disturbance ability.

Summary of the invention

The technical problem to be solved is, not enough for prior art, it is provided that it is abnormal that one is applicable to network wave The control method of the Three-Phase PWM Rectifier become, improves the uneven ability with harmonic distortion of anti-input voltage, suppression output direct current Voltage 2 subharmonic, improves the response speed of output DC voltage simultaneously.

For solving above-mentioned technical problem, the technical solution adopted in the present invention is: a kind of be applicable to waveform distortion of the power supply network The control method of Three-Phase PWM Rectifier, comprises the following steps:

1) sampling current time k three-phase power grid voltage instantaneous value u_a(k)、u_b(k)、u_cOn (k), and current time k for the moment Carve three-phase power grid voltage instantaneous value u_a(k-1)、u_b(k-1)、u_c(k-1)；Sampling current time k three phase network current instantaneous value i_a (k)、i_b(k)、i_c(k), and the upper moment three phase network current instantaneous value i of current time k_a(k-1)、i_b(k-1)、i_c(k-1)； By upper to a current time k three-phase power grid voltage instantaneous value and current time k moment three-phase power grid voltage instantaneous value respectively through Second order power frequency 50Hz wave trap obtains instantaneous value u of current time three phase network fundamental voltage_jf(k) and virtual value U_jf(k), when Instantaneous value u of the upper moment three phase network fundamental voltage of front moment k_jfAnd virtual value U (k-1)_jf(k-1), according to current time k The meritorious p of Three-Phase PWM Rectifier output set_oK () tries to achieve normalized three phase network fundamental currentWherein, j=a, b,c；k≥1；

2) by normalized for current time three-phase first-harmonic reference currentBeing converted by dq, the value after conversion is through two Rank 100Hz band elimination filter, then obtain current time forward-order current reference signal by dq inverse transformation

3) according to Three-Phase PWM Rectifier virtual value I of phase current when three-phase symmetrical input current_balWhen () is tried to achieve current k Carve the negative-sequence current needing to inject $i_{\mathrm{jn}}^{*}\left(k\right)=[i_{\mathrm{jf}}^{*}\left(k\right)-i_{\mathrm{jp}}^{*}\left(k\right)]*I_{\mathrm{bal}}\left(k\right);$

4) three-phase power grid voltage instantaneous value and the three phase network electricity of the subsequent time of current time is predicted respectively according to following formula Stream instantaneous value:

${\hat{u}}_j(k+1)={2u}_j\left(k\right)-u_j(k-1);$

${\hat{i}}_j(k+1)={2i}_j\left(k\right)-i_j(k-1);$

5) by the set-point V of current time Three-Phase PWM Rectifier DC voltage_ref(k) and Three-Phase PWM Rectifier direct current Sampled value u of side voltage_dcK (), as the input of ADRC controller, obtains the current signal I of ADRC controller output_dc(k)；

6) following formula is utilized to obtain the modulation wave signal d of SPWM_a、d_b、d_c, control six power devices of Three-Phase PWM Rectifier Turn off:

$\left\{\begin{array}{c}{d}_a=\frac{{\hat{u}}_a(k+1)-[(I_{\mathrm{dc}}\left(k\right)+p_0\left(k\right)/3*U_{\mathrm{Peak}}\left(k\right)){i_{\mathrm{ap}}}^{*}\left(k\right)-{\hat{i}}_a(k+1)-{i_{\mathrm{an}}}^{*}\left(k\right)]\frac{L_a}{T_s}}{u_{\mathrm{dc}}}\\ d_b=\frac{{\hat{u}}_b(k+1)-[(I_{\mathrm{dc}}\left(k\right)+p_0\left(k\right)/3*U_{\mathrm{Peak}}\left(k\right)){i_{\mathrm{bp}}}^{*}\left(k\right)-{\hat{i}}_b(k+1)-{i_{\mathrm{bn}}}^{*}\left(k\right)]\frac{L_b}{T_s}}{u_{\mathrm{dc}}}\\ d_c=\frac{{\hat{u}}_c(k+1)-[(I_{\mathrm{dc}}\left(k\right)+p_0\left(k\right)/3*U_{\mathrm{Peak}}\left(k\right)){i_{\mathrm{cp}}}^{*}\left(k\right)-{\hat{i}}_c(k+1)-{i_{\mathrm{cn}}}^{*}\left(k\right)]\frac{L_c}{T_s}}{u_{\mathrm{dc}}}\end{array}\right.;$

Wherein, L_a、L_b、L_cIt it is the inductance value of three input filter inductance；T_sFor the three phase network sampling period；U_Peak(k) be Current time three phase network phase voltage peak value.

Described step 1) in, current time k normalized three phase network fundamental currentComputing formula as follows:

$\left\{\begin{array}{c}{i}_{\mathrm{af}}^{*}\left(k\right)=u_{\mathrm{af}}\left(k\right)/\left[\sqrt{2}{R}_{\mathrm{bal}}\left(k\right)I_{\mathrm{bal}}\left(k\right)\right]\\ i_{\mathrm{bf}}^{*}\left(k\right)=u_{\mathrm{bf}}\left(k\right)/\left[\sqrt{2}{R}_{\mathrm{bal}}\left(k\right)I_{\mathrm{bal}}\left(k\right)\right]\\ i_{\mathrm{cf}}^{*}\left(k\right)=u_{\mathrm{cf}}\left(k\right)/\left[\sqrt{2}{R}_{\mathrm{bal}}\left(k\right)I_{\mathrm{bal}}\left(k\right)\right]\end{array}\right.;$

$p_o\left(k\right)=U_{\mathrm{af}}^2\left(k\right)/R_{\mathrm{bal}}\left(k\right)+U_{\mathrm{bf}}^2\left(k\right)/R_{\mathrm{bal}}\left(k\right)+U_{\mathrm{cf}}^2\left(k\right)/R_{\mathrm{bal}}\left(k\right);$ Or,

p_o(k)=U_af(k)I_bal(k)+U_bf(k)I_bal(k)+U_cf(k)I_bal(k)；

Wherein, p_oK () span is 0～100KW； $R_{\mathrm{bal}}\left(k\right)=(U_{\mathrm{af}}^2\left(k\right)+U_{\mathrm{bf}}^2\left(k\right)+U_{\mathrm{cf}}^2\left(k\right))/p_o\left(k\right);$ R_balK () represents current time Three-Phase PWM Rectifier equivalent resistance of each phase when three-phase symmetrical equivalent load；I_bal(k)=(U_af (k)+U_bf(k)+U_cf(k))/p_o(k)。

Compared with prior art, what the had the beneficial effect that present invention of the present invention proposed actively injects negative-sequence current Control method can effectively suppress PWM rectifier output DC voltage in 2 subharmonic, compare than when being not injected into negative-sequence current Reduce the ripple factor of 50%；Meanwhile, the harmonic distortion of input current can effectively be suppressed；The improvement dead beat control that the present invention proposes Method processed improves the response speed of system, effectively reduces overshoot, than use traditional PI control skill upgrading 50% with Upper response speed；Reduce the voltage deviation more than 50% during transient state, can guarantee that PWM rectifier input power factor exists simultaneously More than 0.98；The present invention can be obviously reduced Three-Phase PWM Rectifier and export direct current under input harmonics and unbalance voltage disturbance 2 ripples of voltage, the transient response speed promoting PWM rectifier and reduction DC voltage transient state side-play amount, and improve system Control accuracy.

Accompanying drawing explanation

Fig. 1 is one embodiment of the invention Three-Phase PWM Rectifier topological structure schematic diagram；

Fig. 2 is the topological structure schematic diagram of one embodiment of the invention 2 rank automatic disturbance rejection controller；

Fig. 3 (a) is the reference current signal extraction schematic flow sheet that one embodiment of the invention improves track with zero error；

Fig. 3 (b) is a kind of anti-input harmonics being applicable to Three-Phase PWM Rectifier of one embodiment of the invention and unbalance voltage The improvement dead-beat control method schematic diagram of disturbance；

Fig. 4 is that one embodiment of the invention uses PI and classical dead-beat control method and the controlling party using the present invention to propose Method using effect comparison diagram；Wherein:

When Fig. 4 (a) is PWM rectifier use PI and classical dead-beat control method, unidirectional current during output 10kW Pressure, input current waveform schematic diagram；

Fig. 4 (b) is PWM rectifier when using the control method that the present invention proposes, DC voltage during output 10kW, Input current waveform schematic diagram；

When Fig. 4 (c) is PWM rectifier use PI and classical dead-beat control method, output is at 1kW to 1.2kW ripple The transient response experimental waveform schematic diagram of disorder of internal organs；

When Fig. 4 (d) is the control method that PWM rectifier uses present invention proposition, output fluctuates at 1kW to 1.2kW In transient response experimental waveform schematic diagram；

When Fig. 4 (e) PWM rectifier uses PI and classical dead-beat control method, output is in 1kW to 10kW fluctuates Transient response experimental waveform schematic diagram；

When Fig. 4 (f) PWM rectifier uses the control method that the present invention proposes, output is in 1kW to 10kW fluctuates Transient response experimental waveform schematic diagram.

Detailed description of the invention

As it is shown in figure 1, one embodiment of the invention Three-Phase PWM Rectifier topological structure schematic diagram, wherein, u_a、u_b、u_cAnd i_a、 i_b、i_cIt is three-phase power grid voltage and the three-phase current detection value of commutator access point respectively；L_a、L_b、L_cIt it is input side rectifier Filter inductance, and triphase parameter is symmetrical；R_a、R_b、R_cIt it is the equivalent resistance of filter inductance；R_LIt it is the equivalent resistance of load.Based on KVL can list the transient state equation of commutator equivalent circuit:

$\left\{\begin{array}{c}{u}_{\mathrm{ia}}=u_a-L_a({\mathrm{di}}_a/\mathrm{dt})-R_a{i}_a\\ u_{\mathrm{ib}}=u_b-L_b({\mathrm{di}}_b/\mathrm{dt})-R_b{i}_b\\ u_{\mathrm{ic}}=u_c-L_c({\mathrm{di}}_c/\mathrm{dt})-R_c{i}_c\end{array}\right.---\left(1\right)$

Wherein,

$\left\{\begin{array}{c}{u}_{\mathrm{ia}}=u_{\mathrm{dc}}{S}_a+u_{\mathrm{no}}\\ u_{\mathrm{ib}}=u_{\mathrm{dc}}{S}_b+u_{\mathrm{no}}\\ u_{\mathrm{ic}}=u_{\mathrm{dc}}{S}_c+u_{\mathrm{no}}\end{array}\right.---\left(2\right)$

And

$u_{\mathrm{no}}=-u_{\mathrm{dc}}/3\underset{j=a,b,c}{\mathrm{\Σ}}{S}_j---\left(4\right)$

In Practical Project, owing to the equivalent resistance of input filter inductance is much smaller than its power frequency equivalent reactance, so generally Ignored, following analysis is all assumed ignore this resistance.

Formula (1) discretization can be obtained:

$\left\{\begin{array}{c}{u}_{\mathrm{ia}}\left(k\right)=u_a\left(k\right)-L_a/T_s[i_a(k+1)-i_a\left(k\right)]\\ u_{\mathrm{ib}}\left(k\right)=u_b\left(k\right)-L_b/T_s[i_b(k+1)-i_b\left(k\right)]\\ u_{\mathrm{ic}}\left(k\right)=u_c\left(k\right)-L_c/T_s[i_c(k+1)-i_c\left(k\right)]\end{array}\right.---\left(5\right)$

When three-phase voltage symmetrical when the rectifier topology structure triphase parameter shown in Fig. 1, input balances and is undistorted, ginseng The track with zero error that can obtain classics according to formula (5) realizes formula.

As in figure 2 it is shown, the topological structure schematic diagram of one embodiment of the invention 2 rank automatic disturbance rejection controller, automatic disturbance rejection controller It is made up of Nonlinear Tracking-differentiation element (TD), extended state observer (ESO) and error nonlinear feedback rate (NLSEF). V_refThe tracking signal v that smoothly transits arranged is produced through TD link₁And v₁Differential signal v₂；System output u_dcT () produces through ESO Signal z₁、z₂And z₃, z₁It is u_dcThe tracking signal of (t), z₂It is z₁Differential signal, z₃It is to system model and external disturbance ω The estimation of (t).NLSEF is by deviation ε₁=v₁-z₁With differential deviation ε₂=v₂-z₂Produce basic nonlinear PD control amount u_o(t), By z₃Compensate total disturbance and produce final controlled quentity controlled variable I_dc(t).In fig. 2, due to the input of controller, output signal can be by Following the tracks of accurately, input, the differential signal of output signal can reasonably construct, so, automatic disturbance rejection controller is capable of soon Speed response and non-overshoot.Can obtain at extended state observer link, the change of systematic parameter and the unknown disturbance of its exterior To preferably estimating, so, automatic disturbance rejection controller has stronger Ability of Resisting Disturbance.

In automatic disturbance rejection controller, TD link, ESO link and NLSEF link can select different nonlinear functions, from And form different control realization algorithms, automatic disturbance rejection controller application first has to the system " Relative order of clear and definite controlled device Number ".Operation principle according to PWM rectifier: the output of consideration system is u_dcTime system relative exponent number be 1 rank.But, by In there is inevitable time delay process in sampling, calculating link, although application linear extrapolation can realize predicting the benefit of a bat Repaying property track with zero error, but, this is only approximation, and uncertain inertial element, delay link still can produce uncertain Impact, therefore, is set as 2 rank by control exponent number.Selected parameter of the present invention is prone to adjust and be prone to hard-wired based on linearly ESO realizes the robust control of PWM rectifier outer voltage, and expression is as follows:

$\left\{\begin{array}{c}{v}_1=v_1+{\mathrm{hv}}_2,v_2=v_2+\mathrm{hfhan}(v_1-V_{\mathrm{ref}},v_2,r_1,h)\·\·\·\·\·\·\mathrm{TD}\\ \left.\begin{array}{c}{e}_0=z_1-u_{\mathrm{dc}},z_1=z_1+h(z_2-{\mathrm{\β}}_{01}{e}_0)\\ z_2=z_2+h(z_3-{\mathrm{\β}}_{02}{e}_0+b_0{I}_{\mathrm{dc}}),z_3=z_3+h(-{\mathrm{\β}}_{03}{e}_0)\end{array}\right\}\mathrm{ESO}\\ e_1=v_1-z_1,e_2=v_2-z_2\\ \left.\begin{array}{c}{u}_o=-\mathrm{fhan}(e_1,c_1{e}_2,r_2,h_1)\\ I_{\mathrm{dc}}=u_o-z_3/b_0\end{array}\right\}\·\·\·\·\·\·\·\·\·\·\·\·\·\·\·\·\·\·\·\·\·\·\·\·\·\·\·\mathrm{NLSEF}\end{array}\right.---\left(6\right)$

Wherein, v₁It is V_refThe tracking signal that smoothly transits arranged is produced through TD link；z₁It is u_dcThe tracking signal of (t)；z₂ It is z₁Differential signal；z₃It it is the estimation to system model and external disturbance ω (t)；I_dcFor final controlled quentity controlled variable.

$\left\{\begin{array}{c}{d}_0={\mathrm{rh}}^2,a_0={\mathrm{hx}}_2,y=x_1+a_0\\ a_1=y+a_0,a_2=y+a_0\left(\right|a_0|/d_0-1)/2\\ s_y=(\mathrm{sign}(y-d_0)-\mathrm{sign}(y+d_0))/2\\ s_a=(\mathrm{sign}(a_1-d_0)-\mathrm{sign}(a_1+d_0))/2\\ \mathrm{fhan}=-r((a_1-\mathrm{sign}\left(a_1\right)-\mathrm{sign}\left(a_2\right))s_y{s}_a+\mathrm{sign}\left(a_1\right)+\mathrm{sign}\left(a_2\right))\end{array}\right.---\left(7\right)$

$\mathrm{sign}\left(x\right)=\left\{\begin{array}{cc}1& x>0\\ 0& x=0\\ -1& x<0\end{array}\right.---\left(8\right)$

Function fhan is obtained by formula (7)；Formula (8) obtains function sign.

r₁=0.0001/h²,β₀₁=1/h, β₀₂=1/ (3h²),β₀₃=1/ (32h²),

r₂=0.5/h²,c₁=0.5, h₁=5h (9)

Formula (9) gives the formulating parameters method for designing of automatic disturbance rejection controller, and wherein, h is material calculation.

As shown in Fig. 3 (b), for a kind of anti-input harmonics being applicable to Three-Phase PWM Rectifier of one embodiment of the invention and not The improvement dead-beat control method schematic diagram of balanced voltage disturbance.Track with zero error after improving merges Active Disturbance Rejection Control skill Art, its computing formula is:

$\left\{\begin{array}{c}{d}_a=\frac{{\hat{u}}_a(k+1)-[(I_{\mathrm{dc}}\left(k\right)+p_0\left(k\right)/3*311)i_{\mathrm{ap}}\left(k\right)-{\hat{i}}_a(k+1)-i_{\mathrm{an}}\left(k\right)]\frac{L_a}{T_s}}{U_{\mathrm{dc}}}\\ d_b=\frac{{\hat{u}}_b(k+1)-[(I_{\mathrm{dc}}\left(k\right)+p_0\left(k\right)/3*311)i_{\mathrm{bp}}\left(k\right)-{\hat{i}}_b(k+1)-i_{\mathrm{bn}}\left(k\right)]\frac{L_b}{T_s}}{U_{\mathrm{dc}}}\\ d_c=\frac{{\hat{u}}_c(k+1)-[(I_{\mathrm{dc}}\left(k\right)+p_0\left(k\right)/3*311)i_{\mathrm{cp}}\left(k\right)-{\hat{i}}_c(k+1)-i_{\mathrm{cn}}\left(k\right)]\frac{L_c}{T_s}}{U_{\mathrm{dc}}}\end{array}\right.---\left(1\right)$

Wherein,For forward-order current reference signal；For the suppression 2 injected The negative-sequence current of subharmonic；It it is electrical network kth+1 moment electric current of prediction；Line voltage for kth+1 moment of prediction；p₀For feed-forward power；U_dcFor DC capacitor voltage； T_sFor the sampling period.

As shown in Figure 4, use PI and classical dead-beat control method for one embodiment of the invention and use the present invention to propose Control method using effect comparison diagram.

Fig. 4 (a), 4 (b) are DC voltage during PWM rectifier output 10kW, the contrast of input current waveform figure, right Can obtain than experimental result: due to the Voltage unbalance of input, the unidirectional current of the PWM rectifier output of the classical track with zero error of application Containing 2 bigger subharmonic in pressure, so, its ripple factor is bigger；And control method in this paper is at reference current signal Link is actively filled with suitable negative-sequence current, so, effectively inhibit 2 subharmonic in DC voltage, it will be apparent that fall The low ripple factor of DC voltage, about reduces 50%；Meanwhile, the Harmonics of Input distortion journey that two kinds of methods of application control Degree is quite.

Fig. 4 (c), 4 (d) are PWM rectifier transient response experimental result pair under 1kW to 1.2kW output-power fluctuation Ratio, contrast and experiment can obtain: the method based on ADRC that application proposes and control method based on PI have suitable input Harmonic current and the Ripple Suppression ability of output DC voltage；Control method based on ADRC has faster transient response speed Degree, can promote the response speed of more than 60%, and it is maximum partially to effectively reduce VD transient state than PI controller Shifting amount, reduces about 50%.

Fig. 4 (e), 4 (f) are PWM rectifier transient response experimental result pair under 1kW to 10kW output-power fluctuation Ratio, contrast and experiment can obtain: the method based on ADRC that application proposes and control method based on PI have suitable input Harmonic current and the Ripple Suppression ability of output DC voltage；Control method based on ADRC can promote 50% than PI controller The response speed of left and right, and effectively reduce VD transient state maximum offset about 50%.

Claims (2)

1. the control method of the Three-Phase PWM Rectifier being applicable to waveform distortion of the power supply network, it is characterised in that include following step Rapid:

1) sampling current time k three-phase power grid voltage instantaneous value u_a(k)、u_b(k)、u_c(k), and a current time k upper moment three Phase line voltage instantaneous value u_a(k-1)、u_b(k-1)、u_c(k-1)；Sampling current time k three phase network current instantaneous value i_a(k)、i_b (k)、i_c(k), and the upper moment three phase network current instantaneous value i of current time k_a(k-1)、i_b(k-1)、i_c(k-1)；Ought Front moment k three-phase power grid voltage instantaneous value and the upper moment three-phase power grid voltage instantaneous value of current time k are respectively through second order Power frequency 50Hz wave trap obtains instantaneous value u of current time three phase network fundamental voltage_jf(k) and virtual value U_jf(k), current time Carve instantaneous value u of the upper moment three phase network fundamental voltage of k_jfAnd virtual value U (k-1)_jf(k-1), set according to current time k The Three-Phase PWM Rectifier meritorious p of output_oK () tries to achieve normalized three phase network fundamental currentWherein, j=a, b, c；k ≥1；

2) by normalized for current time three-phase first-harmonic reference currentBeing converted by dq, the value after conversion is through second order 100Hz band elimination filter, then obtain current time forward-order current reference signal by dq inverse transformation

3) according to Three-Phase PWM Rectifier virtual value I of phase current when three-phase symmetrical input current_balK () is tried to achieve current time and is needed Negative-sequence current to be injected

4) three-phase power grid voltage instantaneous value and the three phase network electric current wink of the subsequent time of current time k is predicted respectively according to following formula Duration:

${\hat{u}}_j(k+1)=2u_j\left(k\right)-u_j(k-1);$

${\hat{i}}_j(k+1)=2i_j\left(k\right)-i_j(k-1);$

5) by the set-point V of current time Three-Phase PWM Rectifier DC voltage_ref(k) and Three-Phase PWM Rectifier DC side electricity Sampled value u of pressure_dcK (), as the input of automatic disturbance rejection controller, obtains the current signal I of automatic disturbance rejection controller output_dc(k)；

6) following formula is utilized to obtain the modulation wave signal d of SPWM_a、d_b、d_c, control the pass of six power devices of Three-Phase PWM Rectifier Disconnected:

$\left\{\begin{array}{c}{d}_a=\frac{{\hat{u}}_a(k+1)-\&lsqb;\left(I_{dc}\right(k)+p_0(k)/3*U_{Peak}(k\left)\right){i_{ap}}^{*}\left(k\right)-{\hat{i}}_a(k+1)-{i_{an}}^{*}\left(k\right)\&rsqb;\frac{L_a}{T_s}}{u_{dc}\left(k\right)}\\ d_b=\frac{{\hat{u}}_b(k+1)-\&lsqb;\left(I_{dc}\right(k)+p_0(k)/3*U_{Peak}(k\left)\right){i_{bp}}^{*}\left(k\right)-{\hat{i}}_b(k+1)-{i_{bn}}^{*}\left(k\right)\&rsqb;\frac{L_b}{T_s}}{u_{dc}\left(k\right)}\\ d_c=\frac{{\hat{u}}_c(k+1)-\&lsqb;\left(I_{dc}\right(k)+p_k(k)/3*U_{Peak}(k\left)\right){i_{cp}}^{*}\left(k\right)-{\hat{i}}_c(k+1)-{i_{cn}}^{*}\left(k\right)\&rsqb;\frac{L_c}{T_s}}{u_{dc}\left(k\right)}\end{array}\right.;$

Wherein, L_a、L_b、L_cIt it is the inductance value of three input filter inductance；T_sFor the three phase network sampling period；

U_PeakK () is current time three phase network phase voltage peak value.

The control method of the Three-Phase PWM Rectifier being applicable to waveform distortion of the power supply network the most according to claim 1, its feature exists In, described step 1) in, current time k normalized three phase network fundamental currentComputing formula as follows:

$\left\{\begin{array}{c}{i}_{af}^{*}\left(k\right)=u_{af}\left(k\right)/\&lsqb;\sqrt{2}{R}_{bal}\left(k\right)I_{bal}\left(k\right)\&rsqb;\\ i_{bf}^{*}\left(k\right)=u_{bf}\left(k\right)/\&lsqb;\sqrt{2}{R}_{bal}\left(k\right)I_{bal}\left(k\right)\&rsqb;\\ i_{cf}^{*}\left(k\right)=u_{cf}\left(k\right)/\&lsqb;\sqrt{2}{R}_{bal}\left(k\right)I_{bal}\left(k\right)\&rsqb;\end{array}\right.;$

Wherein, p_oK () span is 0～100KW；

R_balK () represents that current time Three-Phase PWM Rectifier is three The equivalent resistance of each phase during symmetrical equivalent load；

I_bal(k)=(U_af(k)+U_bf(k)+U_cf(k))/p_o(k)。