CN103516249B - A kind of single-phase inverter and waveform controlling method thereof - Google Patents

Abstract

The present invention relates to electric and electronic technical field, be specifically related to a kind of single-phase inverter and waveform controlling method thereof. A kind of single-phase inverter, comprises input DC power V_dc, form single-phase full bridge inverter circuit, filter inductance L, filter capacitor C, load Z, voltage sensor VSEN, current sensor ISEN, A/D change-over circuit, digitial controller and drive circuit by 4 power switch pipes and 4 fly-wheel diodes antiparallel with it. The present invention, in the time that harmonic content is large, adjusts the parameter K of adjustable system, and repetitive controller is played a major role, and makes system have better stability; When harmonic content hour, adjust the parameter K of adjustable system, PI controller is played a major role, make system there is response speed faster. The advantages such as this control program merges and repeats to control and PI controls feature separately, gives full play to the advantage of compound control, makes system have good output waveform, and dynamic response is fast, and the ability of adaptation load is strong.

Description

A kind of single-phase inverter and waveform controlling method thereof

Technical field

The present invention relates to electric and electronic technical field, be specifically related to a kind of single-phase inverter and waveform controlling method thereof.

Background technology

In various power electronic equipments, the range of application of inverter is the most widely, but faces in the application of inverterA lot of nonlinear problems, thereby affected inverter output voltage waveform quality. In these non-linear factors, rectification is negativeCarry and occupy suitable proportion. These non-linear rectified loads are due to the periodic turn-on and turn-off of diode, the topology of whole circuitStructure is cyclically-varying, makes the output current distortion of inverter for a series of pinnacle burst pulse, due to the output of inverterNear impedance value non-vanishing and resonant frequency is very large, and load current will form pressure drop in output impedance, and its harmonic components willCause the wave distortion of power output end voltage, voltage THD value can exceed 5%, when serious, can reach more than 10%, super far awayGo out power supply quality standard, other consumer that also can be docked in inverter electric power system impacts simultaneously, meeting when seriousThereby in circuit, producing concussion causes components and parts to damage. For voltage source inverter system, in order to prevent bridge arm direct passThe dead band time delay arranging also can impact output voltage waveforms.

In order to solve the distortion of inverter output waveform, can reduce by closed loop control method the harmonic wave of output voltage, existingControl method comprises: repeat to control, PI controls, STATE FEEDBACK CONTROL, sliding formwork control, dead beat control etc.; Single controlHave various weak points, in order to solve the deficiency of single control mode, can adopt compound control, at present the most frequently used is compoundControl is two closed loops of PI+repeat to control, but in paper " the PV system interconnection technology based on voltage mode control ", mentions thisCompound control scheme does not have effectively to bring into play the ability of instantaneous value adjuster, and dynamic response is still undesirable, and its reason is, at thisPlant under compound scheme, the input that repeats control and PID adjuster is the tracking error of system, and two adjusters are to same errorRegulate the mutual interference of two regulated quantity phases of result. Owing to also there is no at present a kind of perfect composite controller design method,And two controllers cannot be considered the impact that introducing each other produces original control model when independent design separately exactly, because ofThe performance of this system can not be guaranteed; From another perspective, only using the effect of repetitive controller is that output is followed the tracks of completelyGiven, output voltage and given instruction be without differing, and while only adopting PID adjuster, system output and givenly normally differ, both control characteristic differences, if directly it is also arrived together by force, may cause the confusion of regulating effect. Due toThe existence of above two factors, in order to ensure stability and the stable state output-index of system, normally P, I parameter are got little, butSo just directly sacrifice the dynamic response capability of instantaneous value adjuster, finally often do not reached the original intention of introducing instantaneous value control.

Summary of the invention

The object of the present invention is to provide a kind of single-phase inverter with better dynamic and static performance, object of the present invention also existsIn the waveform controlling method that a kind of single-phase inverter is provided.

The object of the present invention is achieved like this:

A kind of single-phase inverter, comprises input DC power V_dc, by 4 power switch pipes and 4 afterflows two antiparallel with itUtmost point pipe composition single-phase full bridge inverter circuit, filter inductance L, filter capacitor C, load Z, voltage sensor VSEN, electric current passSensor ISEN, A/D change-over circuit, digitial controller and drive circuit, the emitter E termination of the first power switch pipe VT1Form the emitter E end of brachium pontis 1, a three power switch pipe VT3 to the colelctor electrode C end of the second power switch pipe VT2The colelctor electrode C end that is connected to the 4th power switch pipe VT4 forms brachium pontis 2, the colelctor electrode of the first power switch pipe VT1 of brachium pontis 1C end is connected with the colelctor electrode C end of the 3rd power switch pipe VT3 of brachium pontis 2, the second power switch pipe VT2's of brachium pontis 1Emitter E end is connected with the colelctor electrode E end of the 4th power switch pipe VT4 of brachium pontis 2; Dc source V_dcPositive pole be connected toThe colelctor electrode C end of one power switch pipe VT1 and the 3rd power switch pipe VT3, V_dcNegative pole be connected to the second power switch pipeThe emitter E end of VT2 and the 4th power switch pipe VT4; Filter inductance L one end is connected with the mid point A of brachium pontis 1, filtered electricalThe sense L other end is connected with filter capacitor C, and the other end of filter capacitor C is connected on the mid point B of brachium pontis 2; Load Z parallel connectionAt the two ends of capacitor C; The two ends of voltage sensor VSEN are also connected to the two ends of capacitor C, current sensor ISEN series connectionOn the circuit being connected with capacitor C to inductance L; The output voltage signal u that voltage sensor VSEN is detected_cAnd current senseThe current signal i that device ISEN detects_LFeed-in A/D change-over circuit, A/D change-over circuit is by u_cAnd i_LConverting data signal to sendGive digitial controller; In digitial controller to output sinusoidal voltage u_cCarry out harmonic spectrum calculating, extract in real time u_cCertain tonesThe frequency spectrum of the harmonic wave of rate calculates power spectrum according to these harmonic spectrums and regulates in real time adjustable system in adaptive mechanismParameter K, meanwhile by output voltage u_cWith reference voltage u_refSending into error e that subtracter A1 obtains sends into harmonic wave and extracts ringJoint, extraction error e harmonic components is given and is repeated to control G_rpCompensate adjusted value u₂, by u₂K obtains as product with adjustable systemTo compensating signal u₃=Ku₂, meanwhile give G by error e_vAdjusting obtains i_r, then by i_LAnd i_rSend into subtracter A2,The signal obtaining is sent into G_cRegulate adjusted value u₁, finally by signal u₂And u₃Give adder A3 and be compensated signalu_m=u₁+u₃, by u_mGive SPWM modulator and generate pwm signal, then give drive circuit formation driving by pwm signalPulse signal, the gate pole G that finally drive pulse signal is given to 4 power switch pipe VT1～VT4 holds.

Load Z is linear load or nonlinear load.

The waveform controlling method of single-phase inverter comprises: direct-current input power supplying V_dcAfter single-phase full bridge inverter circuit, inversion is for exchangingElectricity, then after LC filter circuit, output sinusoidal voltage u_cWith sinusoidal current i_LGive load Z, use voltage sensor VSENDetect respectively output sinusoidal voltage u with current sensor ISEN_cWith sinusoidal current i_L, then by u_cAnd i_LSend into A/D conversion electricityRoad converts data signal to, finally gives digitial controller by this data signal, in digitial controller, by the output detectingVoltage u_cWith given reference voltage u_refSend into subtracter A1 and make comparisons and obtain error e, meanwhile to output voltage u_cCarry outHarmonic spectrum calculates, to output voltage signal u_cCarry out Fourier space decomposition, extract in real time output voltage signal u_cSpecificThe frequency spectrum of the harmonic wave of frequency, then sends into the harmonic spectrum obtaining in adaptive mechanism, in adaptive mechanism to these harmonic wavesFrequency spectrum calculates power spectrum S (ω), utilizes least-squares algorithm so that harmonic signal power spectrum S (ω) minimum is that principle is real-timeGround regulates the parameter K of adjustable system:

$u_c=c_0+\underset{n=1}{\overset{\∞}{\mathrm{\Σ}}}{a}_n\cos \mathrm{n\ωt}+b_n\sin \mathrm{n\ωt},$

U in formula_cBe output voltage signal, ω=2 π/T is first-harmonic angular frequency, and T is the cycle of signal, c₀DC component, a_n，b_nThe amplitude of mutually orthogonal trigonometric function,

$c_0=\frac{1}{T}\underset{0}{\overset{T}{\∫}}{u}_c\mathrm{dt};$

$\left\{\begin{array}{c}{a}_n=\frac{2}{T}\underset{0}{\overset{T}{\∫}}{u}_c\cos \mathrm{n\ωtdt}\\ b_n=\frac{2}{T}\underset{0}{\overset{T}{\∫}}{u}_c\sin \mathrm{n\ωtdt}\end{array}\right.;$

$S\left(\mathrm{\ω}\right)=\underset{T\→\∞}{\lim }\frac{1}{2T}{\left|U\left(\mathrm{j\ω}\right)\right|}^2;$

U in formula (j ω) is u_cFourier transformation,S (ω) is u_cPower spectrum;

Send into respectively in the two closed loop controllers of two PI in parallel and repetitive controller obtaining error e, first in repetitive controllerFirst error e is sent into harmonic wave and extracted link, extract the harmonic components of error e, the harmonic components of the error e of extracting is sent intoRepetitive control G_rpMiddle adjusting obtains voltage signal u₂，u₂Obtain signal u with the parameter K of adjustable system as product₃=Ku₂：

u_c＝u_f(t)+u_h(t)

$u_f\left(t\right)=\sin \mathrm{\ωt}\·\frac{4}{T}\underset{t-\frac{T}{2}}{\overset{t}{\∫}}{u}_c\sin \mathrm{\ωtdt}+\cos \mathrm{\ωt}\·\frac{4}{T}\underset{t-\frac{T}{2}}{\overset{t}{\∫}}{u}_c\cos \mathrm{\ωtdt}$

U in formula_cOutput voltage signal, u_f(t) be the fundametal compoment instantaneous value of output voltage signal, u_h(t) be output voltage signalHarmonic component instantaneous value;

In the two closed loop controllers of PI, error e is sent into Voltage loop PI controller G_vRegulate and obtain given value of current signal i_r，Then by the output current i detecting_LWith i_rSend into subtracter A2, then the signal obtaining is sent into electric current loop PI controller G_cInRegulate, obtain the regulated value u of the two closed loop controllers of PI₁, finally two controllers in parallel are obtained to signal u₁And u₃AdderA3, is finally compensated signal u_m=u₁+u₃, then compensating signal u_mGive SPWM modulator and generate pwm pulse letterNumber, then give drive circuit formation drive pulse signal by pwm pulse signal, finally drive pulse signal is given single-phase complete4 power switch pipe VT1, VT2, VT3, VT4 in bridge inverter circuit normally work system.

Beneficial effect of the present invention is:

In single-phase inverter Waveform Control system, compared with the compound control of two closed loops of conventional PI+repeat to control, the present inventionThe control method proposing is utilized repetitive controller only to regulate harmonic wave, is not affected the characteristic of first-harmonic, and pi regulator is mainly used in first-harmonicThe quick tracking of instruction, and utilize adaptive mechanism to detect in real time the harmonic content of output voltage, according to the content pair of harmonic waveThe output of repetitive controller is weighted adjusting. In the time that harmonic content is large, adjust the parameter K of adjustable system, make repetitive controllerPlay a major role, make system there is better stability; When harmonic content hour, adjust the parameter K of adjustable system, make PI controlDevice processed plays a major role, and makes system have response speed faster. Repeat to control and PI controls the coupling of regulated quantity each other and mutualDisturb greatly weakened, controller can be respectively according to needing separately independent design in the design phase, PI parameter also without more deliberately a little less thanChange. This control program fusion repeats to control and PI controls feature separately, gives full play to the advantage of compound control, and system is hadGood output waveform, dynamic response is fast, adapts to the advantages such as the ability of load is strong.

Brief description of the drawings

Fig. 1 is single-phase inverter main circuit of the present invention and control structure figure thereof;

Fig. 2 is the control flow chart of the digitial controller of Fig. 1.

Detailed description of the invention

Below in conjunction with accompanying drawing, the present invention will be described in more detail:

The present invention proposes in inverter Waveform Control and separate the method for controlling, utilize repetitive controller and PI controller right respectivelyHarmonic wave and the first-harmonic of inverter output voltage independently regulate separately, and adopt and self-adaptive controlledly in control system, arrangeThe harmonic wave that harmonic wave of output voltage content detection module constantly detects output voltage, enters the output of repetitive controller according to harmonic contentRow weighting control in real time, gives full play to repetitive controller and PI controller feature separately, is that one makes inverter system toolThere is the control method of good dynamic and static performance.

As shown in Figure 1, single-phase inverter main circuit comprises input DC power V_dc，V_dcCan be understood as batteries or itsIts feasible dc source (as rectifier power source); Four power switch pipes (as IGTB, MOSFET etc.) VT1, VT2,VT3, VT4 and four fly-wheel diode VD1s antiparallel with it, VD2, VD3, VD4; The emitter stage of VT1 is connected toThe colelctor electrode of VT2 forms a brachium pontis 1, and the colelctor electrode that the emitter stage of VT3 is connected to VT4 forms 2, two brachium pontis parallel connections of brachium pontisForm single-phase full bridge inverter circuit, dc source V_dcPositive pole be connected to the colelctor electrode of VT1, negative pole is connected to the emitter stage of VT2;Single-phase inverter adopts LC mode filter, the VT1 of filter inductance L one end and inverter circuit brachium pontis 1 and the mid point A of VT2Connect, the other end is connected with filter capacitor C, and the other end of capacitor C is connected to the VT3 of brachium pontis 2 and the mid point B of VT4; NegativeCarry Z(linear load or nonlinear load) be connected in parallel on the two ends of capacitor C.

Control system comprises digitial controller, and current detection circuit is made up of current sensor ISEN, and voltage detecting circuit is by voltageSensor VSEN forms, A/D change-over circuit and drive circuit. Digitial controller comprises the two closed loop controllers of PI, Voltage loop PIController G_v, electric current loop PI controller G_c; Harmonic wave extracts link; Repetitive controller G_rp; Adjustable system K; Voltage harmonic frequentlySpectrum is calculated; Adaptive mechanism, SPWM modulator. Current sensor ISEN is connected on the circuit of inductance L, voltage sensorDevice VSEN is connected in parallel on the two ends of electric capacity R. The output voltage signal u being detected by voltage detecting circuit_cFeed-in A/D change-over circuit,The inductive current i being detected by current detection circuit_LFeed-in A/D change-over circuit; By A/D change-over circuit by u_c、i_LConvert toData signal, then sends into digitial controller. In digitial controller, by output voltage u_cCarry out harmonic spectrum calculating, in real timeGround extracts output voltage signal u_cThe harmonic spectrum (for example 3,5,7,9,11 subharmonic) of CF, at adaptive mechanismMiddlely calculate its power spectrumanalysis according to these harmonic signals and go out harmonic content, utilize least-squares algorithm so that harmonic signal power spectrumMinimum is the parameter K that principle regulates adjustable system in real time. By the voltage signal u feeding back_cWith reference voltage u_refSend into and subtractMusical instruments used in a Buddhist or Taoist mass A1 obtains error e, e is sent into harmonic wave and extract link, extracts its harmonic components, then passes through repetitive controller Gr_pBenefitRepay adjusted value u₂, then by u₂Obtain signal u with K as product₃; In the two closed loop controllers of PI, e is sent into Voltage loopPI controller G_vRegulate and obtain given value of current i_r, then by current signal i_LAnd i_rSend into subtracter A2, then will obtainSignal is sent into electric current loop PI controller G_cAdjusting obtains the regulated value u of the two closed loop controllers of PI₁. Two PI closed loop controllers are mendedSignal u after repaying₁With the signal u after repetitive controller and adjustable system K compensation₃Give adder A3, obtain final compensationSignal u_m=u₁+u₃, then compensating signal u_mGive SPWM modulator and generate pwm signal, given drive circuitForm drive pulse signal, finally give the power switch pipe in full bridge inverter pulse signal.

Shown in Fig. 1 and Fig. 2, dc source V_dcDirect current inversion after single-phase full bridge inverter circuit of input is alternating current,After LC filtering, output sinusoidal voltage is given load Z. Current detection circuit and voltage detecting circuit are respectively by current sensorISEN and voltage sensor VSEN form, for example: Hall current sensor and Hall voltage sensor, voltage sensor VSENAnd be connected to the two ends of filter capacitor C, output voltage u detected_c, current sensor ISEN is connected in series to inductance and is connected with electric capacityCircuit on, inductive current i detected_L. In inversion process by the inductive current i detecting_LWith output voltage u_cSignal is sent intoA/D change-over circuit converts data signal to, then gives digitial controller this data signal.

In digitial controller, harmonic spectrum calculates according to (1) formula output voltage signal u_cCarry out Fourier space decomposition, in real timeExtract output voltage signal u_cThe frequency spectrum (for example n=3,5,7,9,11 subharmonic) of the harmonic wave of CF, adaptiveAnswer in mechanism, according to (4) formula, these harmonic spectrums are calculated to power spectrum, utilize least-squares algorithm so that harmonic signal meritRate spectrum is minimum is the parameter K that principle regulates adjustable system in real time.

$u_c=c_0+\underset{n=1}{\overset{\∞}{\mathrm{\Σ}}}{a}_n\cos \mathrm{n\ωt}+b_n\sin \mathrm{n\ωt}---\left(1\right)$

(1) u in formula_cBe output voltage signal, ω=2 π/T is first-harmonic angular frequency, and T is the cycle of signal, c₀That DC component canTried to achieve a by (2) formula_n，b_nBe the amplitude of mutually orthogonal trigonometric function, (3) formula utilizes the orthogonal property of trigonometric function to derivea_n，b_n。

$c_0=\frac{1}{T}\underset{0}{\overset{T}{\∫}}{u}_c\mathrm{dt}---\left(2\right)$

$\left\{\begin{array}{c}{a}_n=\frac{2}{T}\underset{0}{\overset{T}{\∫}}{u}_c\cos \mathrm{n\ωtdt}\\ b_n=\frac{2}{T}\underset{0}{\overset{T}{\∫}}{u}_c\sin \mathrm{n\ωtdt}\end{array}\right.---\left(3\right)$

$S\left(\mathrm{\ω}\right)=\underset{T\→\∞}{\lim }\frac{1}{2T}{\left|U\left(\mathrm{j\ω}\right)\right|}^2---\left(4\right)$

(4) in formula, U (j ω) is u_cFourier transformation,S (ω) is u_cPower spectrum.

By output voltage u_cWith reference voltage u_refSend into subtracter A1 and obtain departure e, then e is sent into harmonic wave and extract link,Harmonic wave extracts link and uses the Harmonic detection based on instantaneous reactive power theory, and by formula (5), (6) can extract departure e harmonic wavePoint, then pass through repetitive controller G_rpAdjusting, repeating to control is control method based on internal model principle, and system can be overcomeThe error effect that PERIODIC INTERFERENCE is brought, makes input and output signal consistent, finally obtains the regulated value u of repetition control and compensation₂。

u_c＝u_f(t)+u_h(t)(5)

$u_f\left(t\right)=\sin \mathrm{\ωt}\·\frac{4}{T}\underset{t-\frac{T}{2}}{\overset{t}{\∫}}{u}_c\sin \mathrm{\ωtdt}+\cos \mathrm{\ωt}\·\frac{4}{T}\underset{t-\frac{T}{2}}{\overset{t}{\∫}}{u}_c\cos \mathrm{\ωtdt}---\left(6\right)$

(5) u in formula_cOutput voltage signal, u_f(t) be the fundametal compoment instantaneous value of output voltage signal, u_h(t) be output voltage letterNumber harmonic component instantaneous value.

The two closed loop controllers of PI mainly play quick adjustment effect, in the two closed loop controllers of PI, and Voltage loop PI controller G_vAdoptUse electric capacity Voltage Feedback, electric current loop PI controller G_cAdopt the mode of inductor current feedback. Error e is sent into Voltage loop PI controlDevice G processed_vRegulate and obtain given value of current i_r, then by inductive current i_LAnd i_rSend into subtracter A2, then by the signal obtainingSend into electric current loop PI controller G_cRegulate, obtain the regulated value u of the two closed loop controllers of PI₁。

The harmonic content of the output voltage detecting according to adaptive mechanism regulates adjustable system K, in the time that harmonic content is large, adjustsThe parameter K of adjustable system, plays a major role repetitive controller, makes system have better stability; When harmonic content hour,The parameter K of adjusting adjustable system, plays a major role PI controller, makes system have response speed faster. Control repeatingOutput u₂Be weighted control, be compensated signal Ku₂, the signal after two PI closed loop controllers are compensated and weighting controlThe signal of repetitive controller compensation is given adder A3 and is superposeed, and obtains final compensating signal u_m=u₁+Ku₂, then compensationSignal u_mGive SPWM modulator and generate pwm pulse signal, then given drive circuit formation drive pulse signal,The power switch pipe of finally drive pulse signal being given in single-phase full bridge inverter circuit is normally worked circuit.

Claims (1)

1. a waveform controlling method for single-phase inverter, single-phase inverter comprises: input DC power V_dc, by 4 powerThe single-phase full bridge inverter circuit of switching tube and 4 fly-wheel diodes antiparallel with it composition, filter inductance L, filter capacitor C,Load Z, voltage sensor VSEN, current sensor ISEN, A/D change-over circuit, digitial controller and drive circuit, firstThe colelctor electrode C end that the emitter E of power switch pipe VT1 is connected to the second power switch pipe VT2 forms a brachium pontis 1, theThe colelctor electrode C end that the emitter E of three power switch pipe VT3 is connected to the 4th power switch pipe VT4 forms brachium pontis 2, brachium pontis 1The colelctor electrode C end of the first power switch pipe VT1 and the colelctor electrode C of the 3rd power switch pipe VT3 of brachium pontis 2 hold and be connected,The emitter E end of the emitter E end of the second power switch pipe VT2 of brachium pontis 1 and the 4th power switch pipe VT4 of brachium pontis 2Connect; Dc source V_dcPositive pole be connected to the colelctor electrode C end of the first power switch pipe VT1 and the 3rd power switch pipe VT3,V_dcNegative pole be connected to the emitter E end of the second power switch pipe VT2 and the 4th power switch pipe VT4; Filter inductance L one endBe connected with the mid point A of brachium pontis 1, the filter inductance L other end is connected with filter capacitor C by current sensor ISEN, filteringThe other end of capacitor C is connected on the mid point B of brachium pontis 2; Load Z is connected in parallel on the two ends of capacitor C; Voltage sensor VSENTwo ends and be connected to the two ends of capacitor C, current sensor ISEN connects with filter inductance L, then with filter capacitor C and negativeThe parallel circuit that carries Z connects; The output voltage signal u that voltage sensor VSEN is detected_cExamine with current sensor ISENThe current signal i measuring_LFeed-in A/D change-over circuit, A/D change-over circuit is by output voltage signal u_cWith current signal i_LConvert toData signal is given digitial controller; In digitial controller to output voltage signal u_cCarry out harmonic spectrum calculating, carry in real timeGet output voltage signal u_cThe frequency spectrum of the harmonic wave of CF calculates power according to these harmonic spectrums in adaptive mechanismSpectrum regulates the parameter K of adjustable system in real time, meanwhile by output voltage signal u_cWith reference voltage u_refSend into subtracter A1The error e obtaining is sent into harmonic wave and is extracted link, extracts error e harmonic components and gives repetitive controller G_rpCompensate adjusted valueu₂, by u₂Be compensated signal u with the parameter K of adjustable system as product₃＝Ku₂, meanwhile give Voltage loop by error ePI controller G_vAdjusting obtains i_r, then by i_LAnd i_rSend into subtracter A2, the signal obtaining is sent into electric current loop PI controllerG_cRegulate adjusted value u₁, finally by signal u₁And u₃Give adder A3 and be compensated signal u_m＝u₁+u₃, by u_mSendGenerate pwm signal to SPWM modulator, then give drive circuit formation drive pulse signal by pwm signal, finally willDrive pulse signal is given the gate pole G end of 4 power switch pipe VT1～VT4; Described load Z is linear load or non-lineProperty load; It is characterized in that: input DC power V_dcAfter single-phase full bridge inverter circuit, inversion is alternating current, then passes through LC filteringAfter circuit, output voltage signal u_cWith sinusoidal current i_LGive load Z, use voltage sensor VSEN and current sensor ISENDetect respectively output voltage signal u_cWith sinusoidal current i_L, then by output voltage signal u_cWith current signal i_LSending into A/D turnsChange circuit conversion and become data signal, finally give digitial controller by this data signal, in digitial controller, by what detectOutput voltage signal u_cWith given reference voltage u_refSend into subtracter A1 and make comparisons and obtain error e, meanwhile to exporting electricityPress signal u_cCarry out harmonic spectrum calculating, to output voltage signal u_cCarry out Fourier space decomposition, extract in real time output electricityPress signal u_cThe frequency spectrum of the harmonic wave of CF, then sends into the harmonic spectrum obtaining in adaptive mechanism, at adaptive mechanismIn these harmonic spectrums are calculated to power spectrum S (ω), utilize least-squares algorithm so that harmonic signal power spectrum S (ω)Little is the parameter K that principle regulates adjustable system in real time:

$u_c=c_0+\underset{n=1}{\overset{\mathrm{\∞}}{\Σ}}{a}_n\cos n\mathrm{\ω}t+b_n\sin n\mathrm{\ω}t,$

U in formula_cBe output voltage signal, ω=2 π/T is first-harmonic angular frequency, and T is the cycle of signal, c₀DC component, a_n，b_nThe amplitude of mutually orthogonal trigonometric function,

$c_0=\frac{1}{T}\underset{0}{\overset{T}{\∫}}{u}_{c}dt;$

$\left\{\begin{array}{c}{a}_n=\frac{2}{T}\underset{0}{\overset{T}{\∫}}{u}_c\cos n\mathrm{\ω}tdt\\ b_n=\frac{2}{T}\underset{0}{\overset{T}{\∫}}{u}_c\sin n\mathrm{\ω}tdt\end{array}\right.;$

$S\left(\mathrm{\ω}\right)=\underset{T\→\mathrm{\∞}}{\lim }\frac{1}{2T}{\left|U\left(j\mathrm{\ω}\right)\right|}^2;$

U in formula (j ω) is u_cFourier transformation,S (ω) is u_cPower spectrum;

Send into respectively in the two closed loop controllers of two PI in parallel and repetitive controller obtaining error e, first in repetitive controllerFirst error e is sent into harmonic wave and extracted link, extract the harmonic components of error e, the harmonic components of the error e of extracting is sent intoRepetitive controller G_rpMiddle adjusting obtains voltage signal u₂，u₂Obtain signal u with the parameter K of adjustable system as product₃＝Ku₂：

u_c＝u_f(t)+u_h(t)

$u_f\left(t\right)=sin\mathrm{\ω}t\·\frac{4}{T}\underset{t-\frac{T}{2}}{\overset{t}{\∫}}{u}_{c}sin\mathrm{\ω}tdt+cos\mathrm{\ω}t\·\frac{4}{T}\underset{t-\frac{T}{2}}{\overset{t}{\∫}}{u}_{c}cos\mathrm{\ω}tdt$

U in formula_cOutput voltage signal, u_f(t) be the fundametal compoment instantaneous value of output voltage signal, u_h(t) be output voltage signalHarmonic component instantaneous value;

In the two closed loop controllers of PI, error e is sent into Voltage loop PI controller G_vRegulate and obtain given value of current signal i_r，Then by the output current i detecting_LWith i_rSend into subtracter A2, then the signal obtaining is sent into electric current loop PI controller G_cInRegulate, obtain the regulated value u of the two closed loop controllers of PI₁, the signal u finally two controllers in parallel being obtained₁And u₃Pass throughAdder A3, is finally compensated signal u_m＝u₁+u₃, then compensating signal u_mGive SPWM modulator and generate PWMPulse signal, then give drive circuit formation drive pulse signal by pwm pulse signal, finally drive pulse signal is given4 power switch pipe VT1, VT2, VT3, VT4 in single-phase full bridge inverter circuit normally work system.