CN104659813B - A kind of multi-inverter parallel control method of quick harmonic circulating current suppression - Google Patents

Abstract

The invention discloses the multi-inverter parallel control method of a kind of quick harmonic circulating current suppression, pass through i_p‑i_qAlgorithm obtains the harmonic current of inverter output current, by the outer voltage output that is added to after its antiphase, obtain the instruction of current inner loop, thus suppress the harmonic circulating current of inverter output current efficiently, rapidly, it is achieved that the harmonic circulating current suppression of multi-inverter parallel.The invention allows for the computational methods of one " change window " moving average power to improve the calculating of mean power, decrease traditional fixed cycle and calculate the deviation introduced, improve the accuracy that mean power calculates；The proposition that moving average calculates a so that mean power can be calculated in each sampling period, thus substantially increase the real-time of power calculation so that power droop control can be better achieved power-sharing, reduces harmonic circulating current further.The composite can be widely applied in micro-capacitance sensor multi-inverter parallel control system, be especially suitable for the micro-capacitance sensor that band nonlinear load runs.

Description

A kind of multi-inverter parallel control method of quick harmonic circulating current suppression

Technical field

The present invention relates to micro-capacitance sensor multi-inverter parallel and control technical field, it is how inverse that a kind of quick harmonic circulating current suppresses Become device control method for parallel.

Background technology

Increasingly serious along with global energy crisis and problem of environmental pollution, people increasingly pay attention to exploitation and the profit of new forms of energy With, new forms of energy as a kind of widely distributed high-efficiency cleaning energy, to the replacement ratio of traditional energy by increasing.At present, Generation of electricity by new energy is considered as new energy technology the most most with prospects, and various countries put into a huge sum of money one after another and open Send out research, and expand the application of its market energetically.Micro-capacitance sensor is as a kind of effective means of the development and utilization of new forms of energy, permissible Distributed power source is utilized efficiently.

The key issue that micro-capacitance sensor runs is the parallel running of multi-inverter, and when parallel running due to control improper or Person's line impedance is inconsistent, can produce circulation, especially during band nonlinear-load, the m-Acetyl chlorophosphonazo of inverter between inverter Circulation can be the biggest.At present, the general method using virtual impedance reduces circulation, good to first-harmonic loop current suppression effectiveness comparison, But it is difficulty with the suppression to harmonic circulating current, even can increase the aberration rate of inverter output voltage.Therefore research is a kind of fast The multi-inverter parallel control method of speed harmonic circulating current suppression is significant.

Summary of the invention

The technical problem to be solved is, not enough for prior art, it is provided that the suppression of a kind of quick harmonic circulating current is many Inverter parallel control method.

For solving above-mentioned technical problem, the technical solution adopted in the present invention is: many inversions of a kind of quick harmonic circulating current suppression Device control method for parallel, it is adaptable to micro-capacitance sensor multi-inverter parallel system；Described micro-capacitance sensor multi-inverter parallel system includes many The three-phase inversion system of individual parallel connection；DC energy storage electric capacity that described three-phase inversion system includes being sequentially connected with, three phase inverter bridge, LCL filter circuit；Described three-phase inversion system accesses micro-capacitance sensor ac bus by line impedance；Comprise the following steps:

1) in the starting point in each sampling period, sample circuit is to inverter output voltage u_a、u_b、u_c, export electric current i_a、 i_b、i_cSampling, the data then obtained sampling by controller are read out, store；

2) the inverter output voltage u that the 1st step is collected by controller_aIt is sent to digital phase-locked loop (PLL mould in real time Block), it is calculated current phase placeAngular frequency_oWith frequency f；

3) the output electric current i that the 1st step is collected_a、i_b、i_cFrom abc coordinate system transformation to α β coordinate system, obtain i_α、 i_β, its computing formula is:

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

4) by the electric current i under α β coordinate system_α、i_βTransform under rotation dq coordinate system, obtain the electric current i under rotating coordinate system_p、 i_q, its computing formula is as follows:

$\left[\begin{array}{c}{i}_p\\ i_q\end{array}\right]=C_{\mathrm{\α\β}/\mathrm{dq}}\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]=\left[\begin{array}{cc}\sin {\mathrm{\ω}}_{o}t& -\cos {\mathrm{\ω}}_{o}t\\ -\cos {\mathrm{\ω}}_{o}t& -\sin {\mathrm{\ω}}_{o}t\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]$

5) electric current i_p、i_qDC component can be decomposed intoAnd AC compounentBy electric current i_p、i_qPass through low pass After wave filter LPF, obtain DC component

6) by DC componentTransform under α β coordinate system, obtain the DC component electric current under α β coordinate system Its computing formula is as follows:

$\left[\begin{array}{c}\stackrel{\‾}{i_{\mathrm{\α}}}\\ \stackrel{\‾}{i_{\mathrm{\β}}}\end{array}\right]=C_{\mathrm{dq}/\mathrm{\α\β}}\left[\begin{array}{c}\stackrel{\‾}{i_p}\\ \stackrel{\‾}{i_q}\end{array}\right]=\left[\begin{array}{cc}\sin {\mathrm{\ω}}_{o}t& -\cos {\mathrm{\ω}}_{o}t\\ -\cos {\mathrm{\ω}}_{o}t& -\sin {\mathrm{\ω}}_{o}t\end{array}\right]\left[\begin{array}{c}\stackrel{\‾}{i_p}\\ \stackrel{\‾}{i_q}\end{array}\right]$

7) electric current i is used again_α、i_βBecome and deduct DC component electric currentObtain the AC compounent under α β coordinate system Its computing formula is as follows:

$\left\{\begin{array}{c}\widetilde{i_{\mathrm{\α}}}=i_{\mathrm{\α}}-\stackrel{\‾}{i_{\mathrm{\α}}}\\ \widetilde{i_{\mathrm{\β}}}=i_{\mathrm{\β}}-\stackrel{\‾}{i_{\mathrm{\β}}}\end{array}\right.$

8) the inverter output voltage u that the 1st step is collected_a、u_b、u_cFrom abc coordinate system transformation to α β coordinate system, Obtain u_α、u_β, its computing formula is:

$\left[\begin{array}{c}{u}_{\mathrm{\α}}\\ u_{\mathrm{\β}}\end{array}\right]=C_{\mathrm{abc}/\mathrm{\α\β}}\left[\begin{array}{c}{u}_a\\ u_b\\ u_c\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{u}_a\\ u_b\\ u_c\end{array}\right]$

9) the output electric current i that the 3rd step obtains is utilized_α、i_βThe output voltage u obtained with the 8th step_α、u_β, calculating instantaneous has Merit power p and reactive power q, its computing formula is as follows:

$\left[\begin{array}{c}p\\ q\end{array}\right]=\left[\begin{array}{cc}{u}_{\mathrm{\α}}& u_{\mathrm{\β}}\\ u_{\mathrm{\β}}& -u_{\mathrm{\α}}\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]$

10) calculated instantaneous active power p and reactive power q are sent into change window sliding mean power and calculate module, meter Calculation obtains average active power P and reactive power Q, and by current calculated average active power P and nothing Merit power Q stores, and uses in case next time calculates.Its computing formula is as follows:

$\left\{\begin{array}{c}P\left(k\right)=P(k-1)+\frac{1}{N}(p\left(k\right)-p(k-N))\\ Q\left(k\right)=Q(k-1)+\frac{1}{N}(q\left(k\right)-q(k-N))\end{array}\right.$

Wherein k is present sample number of times, and N is the total sampling number in a grid cycle, and just becomes with incoming frequency Ratio；

11) utilize calculated average active power P and reactive power Q, be calculated reference by power droop control Voltage magnitude E and angular frequency, specific formula for calculation is as follows:

$\left\{\begin{array}{c}E=E^{*}-\mathrm{mQ}\\ \mathrm{\ω}={\mathrm{\ω}}^{*}-\mathrm{nP}\end{array}\right.$

Wherein m, n are respectively meritorious and idle sagging coefficient, concrete value by the meritorious capacity of three-phase inversion system and Reactive capability determines；

12) phase place that the 11st step calculated reference voltage amplitude E and angular frequency obtain is utilized with the 2nd stepCarry out three Phase voltage synthesis obtains three-phase reference voltageIts computing formula is as follows:

13) three-phase reference voltage that synthesis is obtainedTransform under α β coordinate system, obtain under α β coordinate system Reference voltageIts computing formula is:

$\left[\begin{array}{c}{u}_{\mathrm{\α}}^{*}\\ u_{\mathrm{\β}}^{*}\end{array}\right]=C_{\mathrm{abc}/\mathrm{\α\β}}\left[\begin{array}{c}{u}_a^{*}\\ u_b^{*}\\ u_c^{*}\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{u}_a^{*}\\ u_b^{*}\\ u_c^{*}\end{array}\right]$

14) i that the 3rd step is obtained_α、i_β, it is multiplied by virtual resistance, then the reference voltage that is added toOn, obtain accurate humorous The PR that shakes controls the voltage reference value of outer voltageObtain in electric current after being controlled by quasi-resonance PR The reference current of ring

15) AC compounent under the α β coordinate system that the 7th step is obtainedPhase place negates, the ginseng of the current inner loop that is added to Examine electric currentOn, obtain reference current

16) by reference currentTransform under abc coordinate system, obtain the reference current of dead-beat current control Obtain three phase inverter bridge through track with zero error and drive dutycycle D of signal_a、D_b、D_c.Transmitted To Drive Protecting Circuit, produce and drive signal, be used for driving inverter.

Compared with prior art, the quick harmonic circulating current suppression that the had the beneficial effect that present invention of the present invention proposes is many Inverter parallel control method, by the outer voltage output that is added to after anti-phase for the harmonic current of inverter output current, obtains electric current The instruction of inner ring, thus inhibit harmonic circulating current efficiently, rapidly.Further it is proposed that a kind of change window sliding is put down All computational methods of power calculate the mean power needed for power droop control, and the proposition that moving average calculates improves power The real-time calculated a so that mean power can be calculated in each sampling period；The proposition of " change window " decreases Fixed cycle calculates the error introduced, and improves the accuracy that mean power calculates, it is achieved thereby that the power of multi-inverter parallel Divide equally, reduce further harmonic circulating current.Present invention achieves the harmonic circulating current suppression of micro-capacitance sensor multi-inverter parallel, can be wide General it is applied in micro grid control system.

Accompanying drawing explanation

Fig. 1 is one embodiment of the invention multi-inverter parallel structural representation；

Fig. 2 is the multi-inverter parallel control method schematic diagram of one embodiment of the invention quick harmonic circulating current suppression；

Fig. 3 is one embodiment of the invention single-phase phase-locked loop computing block diagram；

Fig. 4 is that one embodiment of the invention uses two inverters of the multi-inverter parallel control method of quick harmonic circulating current suppression also Connection current simulations oscillogram.

Fig. 5 (a) is two inverter parallel circulation frequency analysis result figures of traditional droop control method；Fig. 5 (b) is for using this The circulation frequency analysis result figure of inventive method.

Detailed description of the invention

Fig. 1 is one embodiment of the invention multi-inverter parallel structural representation, including three-phase inversion system, control system, line Roadlock is anti-, micro-capacitance sensor ac bus, threephase load；Described three-phase inversion system include DC energy storage electric capacity, three phase inverter bridge, LCL filter circuit；DC energy storage electric capacity, three phase inverter bridge, LCL filter circuit, line impedance, micro-capacitance sensor ac bus, Threephase load is sequentially connected with.Control system includes dsp controller, A/D sample circuit, phase-locked loop module and driving protection electricity Road.

Fig. 2 is the multi-inverter parallel control method schematic diagram of one embodiment of the invention quick harmonic circulating current suppression, mainly by humorous Ripple loop current suppression part, the window sliding mean power that becomes calculate module, phase-locked loop module, power droop control module, virtual Resistive module, quasi-resonance PR control module and dead-beat current control module composition, concrete quick harmonic circulating current suppression Multi-inverter parallel control method comprises the following steps:

1) in the starting point in each sampling period, sample circuit is to inverter output voltage u_a、u_b、u_c, export electric current i_a、 i_b、i_cSampling, the data then obtained sampling by controller are read out, store；

2) the inverter output voltage u that the 1st step is collected by controller_aIt is sent to digital phase-locked loop (PLL mould in real time Block), it is calculated current phase placeAngular frequency_oWith frequency f；

3) the output electric current i that the 1st step is collected_a、i_b、i_cFrom abc coordinate system transformation to α β coordinate system, obtain i_α、 i_β, its computing formula is:

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

4) by the electric current i under α β coordinate system_α、i_βTransform under rotation dq coordinate system, obtain the electric current i under rotating coordinate system_p、 i_q, its computing formula is as follows:

$\left[\begin{array}{c}{i}_p\\ i_q\end{array}\right]=C_{\mathrm{\α\β}/\mathrm{dq}}\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]=\left[\begin{array}{cc}\sin {\mathrm{\ω}}_{o}t& -\cos {\mathrm{\ω}}_{o}t\\ -\cos {\mathrm{\ω}}_{o}t& -\sin {\mathrm{\ω}}_{o}t\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]$

5) electric current i_p、i_qDC component can be decomposed intoAnd AC compounentBy electric current i_p、i_qPass through low pass After wave filter LPF, obtain DC component

6) by DC componentTransform under α β coordinate system, obtain the DC component electric current under α β coordinate system Its computing formula is as follows:

$\left[\begin{array}{c}\stackrel{\‾}{i_{\mathrm{\α}}}\\ \stackrel{\‾}{i_{\mathrm{\β}}}\end{array}\right]=C_{\mathrm{dq}/\mathrm{\α\β}}\left[\begin{array}{c}\stackrel{\‾}{i_p}\\ \stackrel{\‾}{i_q}\end{array}\right]=\left[\begin{array}{cc}\sin {\mathrm{\ω}}_{o}t& -\cos {\mathrm{\ω}}_{o}t\\ -\cos {\mathrm{\ω}}_{o}t& -\sin {\mathrm{\ω}}_{o}t\end{array}\right]\left[\begin{array}{c}\stackrel{\‾}{i_p}\\ \stackrel{\‾}{i_q}\end{array}\right]$

7) electric current i is used again_α、i_βBecome and deduct DC component electric currentObtain the AC compounent under α β coordinate system Its computing formula is as follows:

$\left\{\begin{array}{c}\widetilde{i_{\mathrm{\α}}}=i_{\mathrm{\α}}-\stackrel{\‾}{i_{\mathrm{\α}}}\\ \widetilde{i_{\mathrm{\β}}}=i_{\mathrm{\β}}-\stackrel{\‾}{i_{\mathrm{\β}}}\end{array}\right.$

8) the inverter output voltage u that the 1st step is collected_a、u_b、u_cFrom abc coordinate system transformation to α β coordinate system, Obtain u_α、u_β, its computing formula is:

$\left[\begin{array}{c}{u}_{\mathrm{\α}}\\ u_{\mathrm{\β}}\end{array}\right]=C_{\mathrm{abc}/\mathrm{\α\β}}\left[\begin{array}{c}{u}_a\\ u_b\\ u_c\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{u}_a\\ u_b\\ u_c\end{array}\right]$

9) the output electric current i that the 3rd step obtains is utilized_α、i_βThe output voltage u obtained with the 8th step_α、u_β, calculating instantaneous has Merit power p and reactive power q, its computing formula is as follows:

$\left[\begin{array}{c}p\\ q\end{array}\right]=\left[\begin{array}{cc}{u}_{\mathrm{\α}}& u_{\mathrm{\β}}\\ u_{\mathrm{\β}}& -u_{\mathrm{\α}}\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]$

10) calculated instantaneous active power p and reactive power q are sent into change window sliding mean power and calculate module, meter Calculation obtains average active power P and reactive power Q, and by current calculated average active power P and nothing Merit power Q stores, and uses in case next time calculates.Its computing formula is as follows:

$\left\{\begin{array}{c}P\left(k\right)=P(k-1)+\frac{1}{N}(p\left(k\right)-p(k-N))\\ Q\left(k\right)=Q(k-1)+\frac{1}{N}(q\left(k\right)-q(k-N))\end{array}\right.$

Wherein k is present sample number of times, and N is the total sampling number in a grid cycle, and just becomes with incoming frequency Ratio；

11) utilize calculated average active power P and reactive power Q, be calculated reference by power droop control Voltage magnitude E and angular frequency, specific formula for calculation is as follows:

$\left\{\begin{array}{c}E=E^{*}-\mathrm{mQ}\\ \mathrm{\ω}={\mathrm{\ω}}^{*}-\mathrm{nP}\end{array}\right.$

Wherein m, n are respectively meritorious and idle sagging coefficient, and concrete numerical value is by the meritorious capacity of each inverter and idle Capacity determines；

12) phase place that the 11st step calculated reference voltage amplitude E and angular frequency obtain is utilized with the 2nd stepCarry out three Phase voltage synthesis obtains three-phase reference voltageIts computing formula is as follows:

13) three-phase reference voltage that synthesis is obtainedTransform under α β coordinate system, obtain under α β coordinate system Reference voltageIts computing formula is:

$\left[\begin{array}{c}{u}_{\mathrm{\α}}^{*}\\ u_{\mathrm{\β}}^{*}\end{array}\right]=C_{\mathrm{abc}/\mathrm{\α\β}}\left[\begin{array}{c}{u}_a^{*}\\ u_b^{*}\\ u_c^{*}\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{u}_a^{*}\\ u_b^{*}\\ u_c^{*}\end{array}\right]$

14) i that the 3rd step is obtained_α、i_β, it is multiplied by virtual resistance, then the reference voltage that is added toOn, obtain accurate humorous The PR that shakes controls the voltage reference value of outer voltageObtain in electric current after being controlled by quasi-resonance PR The reference current of ring

15) AC compounent under the α β coordinate system that the 7th step is obtainedPhase place negates, the ginseng of the current inner loop that is added to Examine electric currentOn, obtain reference current

16) by reference currentTransform under abc coordinate system, obtain the reference current of dead-beat current control Obtain three phase inverter bridge through track with zero error and drive dutycycle D of signal_a、D_b、D_c.Transmitted To Drive Protecting Circuit, produce and drive signal, be used for driving inverter.

Fig. 3 is one embodiment of the invention single-phase phase-locked loop computing block diagram, u in figure_aFor line voltage, by line voltage u_aPhase After steric retardation 90 ° to construct β phase virtual orthographic signal u_β, thus construct two-phase virtual orthographic system, it is thus achieved that the positive alternating current of two-phase Pressure u_α、u_β, then to two-phase quadrature voltage u_α、u_βDo α β/dq coordinate transform, obtain micro-capacitance sensor magnitude of voltage d axle component u_d With micro-capacitance sensor magnitude of voltage q axle component u_q, by u_dReference value be set to 0, it is carried out PI control, current electricity can be obtained The angular frequency of net, then the phase place of current electric grid is obtained through integration

Fig. 4 is that one embodiment of the invention uses two inverters of the multi-inverter parallel control method of quick harmonic circulating current suppression also Connection current simulations oscillogram.Assuming that inverter capacity is 9kVA, inverter 1 line impedance value is 0.2+j0.03 Ω, Inverter 2 line impedance value is 0.25+j0.04 Ω, and carrier frequency is set to 10kHZ, loads the resistive load into 6.6kW, i_a1、i_a2Respectively flow through the A phase current of inverter 1,2, i_aHFor the A phase circulation between inverter, it is defined as i_aH=(i_a1-i_a2)/2, the most only inverter 1 isolated operation, i_aH=i_a1/2；After 0.5s, inverter 2 is incorporated to system, electricity Stream i_a1Gradually become original half, after transient process terminates, i_a1With i_a2Amplitude, phase place essentially identical, i_aHThe most basic Trend towards zero.

Fig. 5 is that one embodiment of the invention uses the multi-inverter parallel control method of quick harmonic circulating current suppression and traditional sagging Two inverter parallel circulation frequency analysis comparison diagrams of control method.Wherein figure a is traditional control method circulation frequency analysis knot Really, figure b is quick harmonic circulating current proposed by the invention suppression control method circulation frequency analysis result, right by two figures Ratio, hence it is evident that it can be seen that after using quick harmonic circulating current suppression control method proposed by the invention, the high frequency of harmonic circulating current Harmonic content significantly reduces.

Claims (5)

1. the multi-inverter parallel control method of a quick harmonic circulating current suppression, it is adaptable to micro-capacitance sensor multi-inverter parallel system； Described micro-capacitance sensor multi-inverter parallel system includes the three-phase inversion system of multiple parallel connection；Described three-phase inversion system includes depending on The DC energy storage electric capacity of secondary connection, three phase inverter bridge, LCL filter circuit；Described three-phase inversion system passes through line impedance Access micro-capacitance sensor ac bus；It is characterized in that, comprise the following steps:

1) in the starting point in each sampling period, to three-phase inversion system output voltage u_a、u_b、u_c, export electric current i_a、i_b、 i_cSample；

2) by described three-phase inversion system output voltage u_aIt is sent to digital phase-locked loop, is calculated current phase placeAngular frequency_o With frequency f；By described three-phase inversion system output voltage u_a、u_b、u_cFrom abc coordinate system transformation to α β coordinate system, Obtain the voltage u under α β coordinate system_α、u_β；By three-phase inversion system output current i_a、i_b、i_cFrom abc coordinate system transformation Under α β coordinate system, obtain the electric current i under α β coordinate system_α、i_β；

3) by the electric current i under α β coordinate system_α、i_βTransform under rotation dq coordinate system, obtain the electric current i under rotating coordinate system_p、 i_q；

4) by electric current i_p、i_qAfter low pass filter, obtain DC component

5) by DC componentTransform under α β coordinate system, obtain DC component electric current

6) electric current i is used_α、i_βDeduct DC component electric currentObtain the AC compounent under α β coordinate system

7) electric current i is utilized_α、i_β, voltage u_α、u_βThe instantaneous active power p of calculating three-phase inversion system and reactive power q:

$\left[\begin{array}{c}p\\ q\end{array}\right]=\left[\begin{array}{cc}{u}_{\mathrm{\α}}& u_{\mathrm{\β}}\\ u_{\mathrm{\β}}& -u_{\mathrm{\α}}\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right];$

8) instantaneous active power p and reactive power q is utilized to calculate average active power P and reactive power Q:

$\left\{\begin{array}{c}P\left(k\right)=P(k-1)+\frac{1}{N}\left(p\right(k)-p(k-N\left)\right)\\ Q\left(k\right)=Q(k-1)+\frac{1}{N}\left(q\right(k)-q(k-N\left)\right)\end{array}\right.;$

Wherein k is present sample number of times；N is the total sampling number in a grid cycle；P (k) is the instantaneous of kth time sampling Active power；Q (k) is the instantaneous reactive power of kth time sampling；P (k) is the average active power of kth time sampling；Q(k) The average reactive power of kth time sampling；

9) utilize described average active power P and reactive power Q, be calculated reference voltage amplitude E by power droop control And angular frequency:

$\left\{\begin{array}{c}E=E^{*}-mQ\\ \mathrm{\ω}={\mathrm{\ω}}^{*}-nP\end{array}\right.;$

Wherein E^*、ω^*Representing the rated output voltage amplitude of three-phase inversion system and specified output angle frequency respectively, m, n divide Not for gain merit and idle sagging coefficient；

10) reference voltage amplitude E, angular frequency and phase place are utilizedCarry out three-phase voltage synthesis, obtain three-phase reference voltage

11) three-phase reference voltage that synthesis is obtainedTransform under α β coordinate system, obtain under α β coordinate system Reference voltage

12) by the electric current i under α β coordinate system_α、i_βIt is multiplied by virtual resistance, then the reference voltage that is added toOn, obtain standard Resonance PR controls the voltage reference value of outer voltageCurrent inner loop is obtained after being controlled by quasi-resonance PR Reference current

13) by the AC compounent under α β coordinate systemPhase place negates, the reference current of the current inner loop that is added toOn, Obtain reference current

14) by reference currentTransform under abc coordinate system, obtain the reference current of dead-beat current control Obtain three phase inverter bridge through track with zero error and drive dutycycle D of signal_a、D_b、D_c, by dutycycle D_a、D_b、 D_cIt is sent to Drive Protecting Circuit, produces and drive signal, be used for driving three-phase inversion system.

The multi-inverter parallel control method of quick harmonic circulating current the most according to claim 1 suppression, it is characterised in that Described step 2) in, the electric current i under α β coordinate system_α、i_βAnd the voltage u under α β coordinate system_α、u_βComputing formula is divided It is not:

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

$\left[\begin{array}{c}{u}_{\mathrm{\α}}\\ u_{\mathrm{\β}}\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{u}_a\\ u_b\\ u_c\end{array}\right].$

The multi-inverter parallel control method of quick harmonic circulating current the most according to claim 1 suppression, it is characterised in that Described step 3) in, the electric current i under rotating coordinate system_p、i_qComputing formula is:

$\left[\begin{array}{c}{i}_p\\ i_q\end{array}\right]=\left[\begin{array}{cc}{\mathrm{sin\ω}}_{o}t& -{\mathrm{cos\ω}}_{o}t\\ -{\mathrm{cos\ω}}_{o}t& -{\mathrm{sin\ω}}_{o}t\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right].$

The multi-inverter parallel control method of quick harmonic circulating current the most according to claim 1 suppression, it is characterised in that Described step 5) in, DC component electric currentComputing formula is:

$\left[\begin{array}{c}\stackrel{\‾}{i_{\mathrm{\α}}}\\ \stackrel{\‾}{i_{\mathrm{\β}}}\end{array}\right]=\left[\begin{array}{cc}{\mathrm{sin\ω}}_{o}t& -{\mathrm{cos\ω}}_{o}t\\ -{\mathrm{cos\ω}}_{o}t& -{\mathrm{sin\ω}}_{o}t\end{array}\right]\left[\begin{array}{c}\stackrel{\‾}{i_p}\\ \stackrel{\‾}{i_q}\end{array}\right].$

The multi-inverter parallel control method of quick harmonic circulating current the most according to claim 1 suppression, it is characterised in that Described step 8) in, the computing formula of N is: N=round (λ f)；λ is the ratio of sample frequency and mains frequency.