CN106300354A - A kind of grid-connected converter self adaptation voltage feed-forward control compensation method - Google Patents

Abstract

The open a kind of grid-connected converter self adaptation voltage feed-forward control compensation method of the present invention, belongs to the electric current control field of grid-connected converter (including inverter and commutator).The method comprises the steps: point of common coupling line voltage of sampling, and the input signal compensated as grid-connected converter self adaptation voltage feed-forward control using this voltage, described input signal produces one group of output signal via the band filter at one group of harmonic frequency in parallel, each individual output signals in this group output signal carries out be added generation and is used for the voltage signal of feedforward compensation；Described each individual output signals is carried out Resonance detector simultaneously, when the amplitude certain output signal being detected is uprushed, according to adaptive logic, related output signal is removed from the voltage signal being used for feedforward compensation.The present invention has the strong adaptability to wide variation electric network impedance, current on line side is superior in quality, design convenient advantage.

Description

A kind of grid-connected converter self adaptation voltage feed-forward control compensation method

Technical field

The present invention relates to a kind of grid-connected converter self adaptation voltage feed-forward control compensation method, belong to grid-connected converter (bag Include inverter and commutator) electric current control field.

Background technology

Along with new forms of energy distributed grid-connected generating flourish, grid-connected converter obtains extensively as its key component Concern.And use the current transformer of pulse modulation technology to produce substantial amounts of switching frequency subharmonic.Between current transformer and electrical network Access wave filter and can effectively suppress harmonic wave.Conventional wave filter includes L and LCL filter.Higher grid-connected for realizing Power factor and relatively low current on line side harmonic distortion, existing scholar proposes substantial amounts of grid-connected converter control method.But It is that existing more ripe control method all only accounts for preferable electrical network.Actual electric network (exactly, point of common coupling (point of common coupling, PCC)) uncertain factor that exists can deteriorate systematic function, even results in shakiness Fixed.On the one hand, there is abundant low-frequency harmonics composition in line voltage at PCC point；On the other hand, it is contemplated that longer power transmission and distribution Circuit, more isolating transformer, substantial amounts of Distributed-generation equipment are mounted on the factors such as PCC, and at PPC point, electrical network exists certain Impedance and typically present perception in lower frequency ranges.

For overcoming the line voltage low-frequency harmonics distortion impact on current on line side quality, a class method is to utilize harmonic resonance The high open-loop gain of controller realizes preferable harmonics restraint, and the method is required for multiple harmonic and uses multiple resonance to control Device；Another kind of method is to utilize voltage feed-forward control to improve current on line side quality.For comparing, voltage feed-forward control compensates The dynamic response of grid-connected converter can also be optimized, it is thus achieved that be widely applied in addition to can improving current on line side quality.But The light current can not ignore at electric network impedance is off the net, and line voltage (exactly, PCC voltage) feedforward compensation can cause current on line side Occur that even more serious harmonic distortion even occurs that instability triggers grid-connected converter protection.Existing for solving system instability As, there is scholar to propose and only the first-harmonic composition of PCC voltage is used for feedforward compensation.This method solve light current grid-connected converter off the net Device instability problem, but the method sacrifices PCC electric voltage feed forward and compensates the rejection ability to current on line side harmonic wave, is unfavorable for carrying The grid-connected converter current on line side quality that high light current is off the net.

The above analysis, it is humorous that PCC electric voltage feed forward compensates the current on line side that can preferably suppress line voltage distortion to cause Ripple, but it is easily caused system stability variation at light current feedforward compensation off the net and causes serious current on line side harmonic distortion. Existing typical case's feedforward compensation method is difficult to take into account stability and the current on line side quality of light current grid-connected converter off the net.

Therefore, optimize field at grid-connected converter current quality, need to study a kind of adapting to and include the various of light current net Electrical network occasion, take into account stability and current on line side quality and realize convenient voltage feed-forward control compensation method.

Summary of the invention

The invention provides a kind of grid-connected converter self adaptation voltage feed-forward control compensation method, it has becoming on a large scale Change the strong adaptability of electric network impedance, current on line side is superior in quality, design convenient advantage, it is adaptable to single-phase and three-phase L filters also The electric current control of net current transformer, single-phase and three-phase LCL filtering and the current on line side of other pattern filtering grid-connected converter or unsteady flow Device side electric current controls.

The present invention solves that its technical problem adopts the following technical scheme that

A kind of grid-connected converter self adaptation voltage feed-forward control compensation method, comprises the steps:

(1) sampling point of common coupling line voltage u_g, and using this point of common coupling line voltage as grid-connected converter certainly Adapt to the input signal that voltage feed-forward control compensates, described input signal via one group of frequency in parallel be 1, the n times of first-harmonic in 3 ... Band filter at frequency also produces one group of band filter output signal, is designated as u respectively_{g_1}、u_{g_3}、…u_{g_n}, by defeated for this group Each the independent band filter output signal gone out in signal is respectively fed to Resonance detector module and adaptive logic module；

(2) each band filter output signal is through Resonance detector module, produces the defeated of signal amplitude or virtual value change Go out information, and this information is sent into adaptive logic module；

(3) the output information of Resonance detector module and each band filter output signal are through adaptive logic module, The voltage signal u for feedforward compensation is produced according to adaptive logic_{g_ff}。

In described step (3), adaptive logic is: when certain band filter output signal u being detected_{g_i}Amplitude occur prominent During increasing, by band filter output signal u_{g_i}～u_{g_n}From feedforward compensation voltage u_{g_ff}Middle removal；When detecting that certain several band leads to Filter output signal u_{g_j}～u_{g_i}Amplitude when uprushing, first by u_{g_i}～u_{g_n}From feedforward compensation voltage u_{g_ff}In Remove, continue after removal each band filter output signal is detected, if u_{g_j}～u_{g_i-2}The biggest then by u_{g_i-2}From feedforward Compensate voltage u_{g_ff}Middle removal, the rest may be inferred, wherein, and i=3,5 ... n, j=3,5 ... n and j < i.

For the voltage signal u of feedforward compensation described in described step (3)_{g_ff}, even ignore electric network impedance is the least Under electrical network occasion, u_{g_ff}Equal to u_{g_1}、u_{g_3}、…u_{g_n}Sum.

For the voltage signal u of feedforward compensation described in described step (3)_{g_ff}, change in a big way at electric network impedance Under electrical network occasion, along with electric network impedance is gradually increased, successively from the voltage signal u for feedforward compensation_{g_ff}Middle removal u_{g_n}、 u_{g_n-2}、…u_{g_3}。

For the voltage signal u of feedforward compensation described in described step (3)_{g_ff}, at the electrical network occasion that impedance is the biggest, u_{g_ff} First-harmonic ingredient u equal to point of common coupling line voltage_{g_1}。

Beneficial effects of the present invention is as follows:

1) stability that during electric network impedance wide variation, grid-connected converter is stronger.

2) when electric network impedance wide variation and line voltage distortion, grid-connected converter is excellent current on line side quality and Preferably dynamic property.

4) without to measure by additionally online or off-line electric network impedance.

5) it is applicable to single-phase and three-phase L, LCL filtering and the grid-connected converter system of other pattern filtering.

Accompanying drawing explanation

Fig. 1 is the grid-connected converter system construction drawing of application the inventive method, wherein: u_gFor PCC voltage；i_gFor net side electricity Stream；u_invFor grid-connected converter brachium pontis output voltage；u₁Output for rheonome；u₂Output for feedforward compensation link；u_m For modulating wave；k_PWMRepresent current transformer brachium pontis link gain；G_L(s) or G_LCLS () is wave filter link；G_{h_1}(s)、G_{h_3} (s)、...、G_{h_n}S () is 1,3 ..., band filter at n times of fundamental frequency；u_{g_1}、u_{g_3}、…u_{g_n}For G_{h_1}(s)、G_{h_3} (s)、...、G_{h_n}The output signal of (s)；u_{g_ff}For the voltage signal for feedforward compensation；G_fS () is feedforward compensation link.

Fig. 2 is that the single-phase LCL that the present invention is applied filters combining inverter circuit structure diagram, wherein: L₁For current transformer side Inductance；C₁For filter capacitor；L₂For net side inductance；U_dcFor DC bus-bar voltage；u_invFor grid-connected converter brachium pontis output voltage；i_g For current on line side；i_C1For capacitance current；u_gFor PCC voltage；u_sFor preferable line voltage；Z_gFor electric network impedance.

Fig. 3 is the double-current feedback control principle figure that conventional additional voltage feed-forward control compensates, wherein: L₁For current transformer Side inductance；C₁For filter capacitor；L₂For net side inductance；u_invFor grid-connected converter brachium pontis output voltage；i_gFor current on line side；i_C1For Capacitance current；u_gFor PCC voltage；u_sFor preferable line voltage；Z_gFor electric network impedance；u₁Output for rheonome；u₂For The output of feedforward compensation link；u_mFor modulating wave；k_PWMRepresent current transformer brachium pontis link gain；G_fS () is feedforward compensation link；G_c S () is rheonome；k_CFor capacitance current proportional feedback factor；i_refFor given current reference.

System open loop Bode diagram when Fig. 4 is that under Fig. 3 control program, electric network impedance is bigger, wherein: β represents in electric network impedance Perceptual weight is with the ratio of inverter total inductance value own.

Fig. 5 is the double-current feedback control principle figure of additional self adaptation voltage feed-forward control compensation method of the present invention, wherein: L₁For current transformer side inductance；C₁For filter capacitor；L₂For net side inductance；u_invFor grid-connected converter brachium pontis output voltage；i_gFor net Side electric current；i_C1For capacitance current；u_gFor PCC voltage；u_sFor preferable line voltage；Z_gFor electric network impedance；u₁For rheonome Output；u₂Output for feedforward compensation link；u_mFor modulating wave；k_PWMRepresent current transformer brachium pontis link gain；G_fS () is feedforward Compensation tache；G_cS () is rheonome；k_CFor capacitance current proportional feedback factor；i_refFor given current reference；G_{h_1} (s)、G_{h_3}(s)、...、G_{h_n}S () is 1,3 ..., band filter at n times of fundamental frequency；u_{g_1}、u_{g_3}、…u_{g_n}For G_{h_1} (s)、G_{h_3}(s)、...、G_{h_n}The output signal of (s)；u_{g_ff}For the voltage signal for feedforward compensation.

System open loop Bode diagram when Fig. 6 is that in Fig. 5 control program, adaptive logic module does not works and electric network impedance is bigger, Wherein: β represents the ratio with inverter total inductance value own of the perceptual weight in electric network impedance；u_{g_ff}For the electricity for feedforward compensation Pressure signal；u_{g_1}、u_{g_3}、u_{g_5}、u_{g_7}It it is the output signal of band filter at 1,3,5,7 times of fundamental frequencies.

System open loop baud when Fig. 7 is that under Fig. 5 control program, adaptive logic module normally works and electric network impedance is bigger Figure, wherein: β represents the ratio with inverter total inductance value own of the perceptual weight in electric network impedance；u_{g_ff}For for feedforward compensation Voltage signal；u_{g_1}、u_{g_3}、u_{g_5}It it is the output signal of band filter at 1,3,5 times of fundamental frequencies.

Fig. 8 is grid-connected converter running and line voltage current waveform after electric network impedance is uprushed under Fig. 5 control program Figure, wherein: β represents the ratio with inverter total inductance value own of the perceptual weight in electric network impedance；u_{g_5}、u_{g_7}It is 5,7 times of first-harmonics The output signal of band filter at frequency；i_gFor current on line side；u_gFor PCC voltage；T is the time.

Fig. 9 is current on line side and PCC voltage transient waveforms figure under Fig. 3 control program, wherein: β represents in electric network impedance Perceptual weight is with the ratio of inverter total inductance value own；i_gFor current on line side；u_gFor PCC voltage；T is the time.

Figure 10 is current on line side and PCC voltage transient waveforms figure under Fig. 5 control program, wherein: β represents in electric network impedance Perceptual weight is with the ratio of inverter total inductance value own；i_gFor current on line side；u_gFor PCC voltage；T is the time.

Detailed description of the invention

Below with reference to accompanying drawing, technical scheme is described in detail.

The present invention provides a kind of grid-connected converter voltage feed-forward control compensation method, as it is shown in figure 1, its be applicable to single-phase and The electric current of three-phase L filtering grid-connected converter controls, single-phase and three-phase LCL filtering, single-phase and other pattern of three-phase grid-connected change of filtering Current on line side or the current transformer side electric current of stream device control.Described method is when implementing, and sampling point of common coupling line voltage (is designated as u_g), and the input signal compensated as grid-connected converter self adaptation voltage feed-forward control using this point of common coupling line voltage, institute State the input signal band filter product via one group of harmonic frequency in parallel (i.e. frequency be 1, the fundamental frequency of 3 ... n times) place Raw one group of band filter output signal (is designated as u respectively_{g_1}、u_{g_3}、…u_{g_n}), each in this group output signal is individually carried Pass filter output signal is respectively fed to Resonance detector module and adaptive logic module.In Resonance detector module, to each band Pass filter output signal u_{g_3}、…u_{g_n}It is monitored and each signal amplitude or virtual value change information are sent into adaptive logic Module；In adaptive logic module, according to the output information of adaptive logic and Resonance detector module, by each band filter Output signal carries out being added the voltage signal produced for feedforward compensation and (is designated as u_{g_ff}).Wherein, adaptive logic is: work as detection (it is designated as u to certain band filter output signal_{g_i}, when i=3,5 ... amplitude n) is uprushed, this band filter is exported Signal u_{g_i}～u_{g_n}From feedforward compensation voltage u_{g_ff}Middle removal；When detecting that certain several band filter output signal (is designated as u_{g_j} ～u_{g_i}, i=3,5 ... n, j=3,5 ... n and j are < when amplitude i) is uprushed, first by u_{g_i}～u_{g_n}From feedforward compensation Voltage u_{g_ff}Middle removal, continues after removal to detect each band filter output signal, if u_{g_j}～u_{g_i-2}The most then will u_{g_i-2}From feedforward compensation voltage u_{g_ff}Middle removal, the rest may be inferred.

As a example by a single-phase LCL filtering grid-connected converter system, concrete example explanation given below.

Single-phase LCL shown in Fig. 2 filters combining inverter, by bridge type inverse topology, inverter side inductance L₁, filter capacitor C₁With net side inductance L₂Composition.In example, DC voltage U_dcFor 400V, preferable line voltage u_sFor 220V/50Hz, specified merit Rate 5kW, inductance L₁For 0.75mH, L₂For 0.45mH, filter capacitor C₁Being 6.8 μ F, switching frequency is 15kHz.In example, Z_gFor Perception, it may be assumed that

Z_g=β (L₁+L₂)s (1)

In formula, β represents the electrical network emotional resistance value ratio with inverter total inductance value own；S is the complex frequency in complex frequency domain Variable.

Fig. 3 is the block diagram of the double-current feedback control (being designated as control schemes) that additional voltage feed-forward control compensates.By It is PCC point in the line voltage sampling location of light current reality off the net, thus the input of feedforward compensation link is PCC voltage u_g, it may be assumed that (subscript " _ sample " represents PCC voltage sample value)

u_{g_sample}=u_g=u_s+i_g·Z_g (2)

In formula, i_gFor current on line side.

Thus, the light current changed in a big way at electric network impedance is off the net, and voltage feed-forward control compensates and electric network impedance makes (feedback factor is Z to there is an extra current on line side positive feedback loop in Fig. 3_g)。

I in Fig. 3 control schemes_refTo i_gOpen-loop transfer function be: (subscript " _ o " represent open loop function)

$G_{i_{ref}\_o}^{i_g}\left(s\right)=\frac{k_{PWM}{G}_c\left(s\right)}{L_1{C}_1{s}^2(L_{2}s+Z_g)+k_c{k}_{PWM}(L_{2}s+Z_g)C_{1}s+(L_1+L_2)s+Z_g-Z_g{k}_{PWM}{G}_f\left(s\right)}---\left(3\right)$

In formula, k_PWMRepresent current transformer brachium pontis link gain；G_fS () is feedforward compensation link；G_cS () is rheonome； k_CFor capacitance current proportional feedback factor.

It can be seen that the common effect of feedforward compensation and electric network impedance makes to have had more a coefficient entry in formula (3).

Fig. 4 gives the control schemes open loop Bode diagram when electric network impedance wide variation.In β=2, phase place is abundant Degree has reduced to 14 °, and during β=3, phase margin has reduced to less than 10 °, and being greatly reduced of phase margin can cause in current on line side Low-frequency harmonics in 1kHz presents significantly increase, easily triggers grid-connected converter over-current over-voltage protection.And, even more serious Be, along with being gradually increased of electric network impedance, phase margin finally less than 0 and make system unstable.Existing voltage feed-forward control is mended Compensation method is difficult to ensure that light current grid-connected converter off the net is stablized and preferable current on line side quality.Thus, it is necessary to research one Plant be applicable to the light current net occasion of electric network impedance wide variation, function admirable and realize the compensation of convenient voltage feed-forward control Method.

Fig. 5 gives and uses the LCL of self adaptation voltage feed-forward control compensation method of the present invention as shown in Figure 1 to filter grid-connected Inverter current control structure.In the inventive method, point of common coupling line voltage u_gFirst via one group of harmonic wave in parallel frequency The band filter at rate (i.e. frequency be 1, the fundamental frequency of 3 ... n times) place, this band filter G_{h_n}S the expression formula of () is as follows:

$G_{h\_n}\left(s\right)=\frac{{\mathrm{\&omega;}}_{c}s}{s^2+{\mathrm{\&omega;}}_{c}s+{(n\&CenterDot;{\mathrm{\&omega;}}_0)}^2}---\left(4\right)$

In formula, ω₀For line voltage first-harmonic angular frequency, ω_cPass band for band filter.Band filter exports Signal u_{g_3}、…u_{g_n}Input Resonance detector module, u_{g_1}、u_{g_3}、…u_{g_n}Input adaptive logic module.

In Resonance detector module, to u_{g_3}、…u_{g_n}Signal amplitude or virtual value detect, when certain signal being detected When uprushing, transmit this information in adaptive logic module.

In adaptive logic module, when Resonance detector module detects that certain band filter output signal (is designated as u_{g_i}, i =3, when 5 ... amplitude n) is uprushed, by this band filter output signal u_{g_i}～u_{g_n}From feedforward compensation voltage u_{g_ff}In Remove；When detecting that certain several band filter output signal (is designated as u_{g_j}～u_{g_i}, i=3,5 ... n, j=3,5 ... n and j < I) when amplitude is uprushed, first by u_{g_i}～u_{g_n}From feedforward compensation voltage u_{g_ff}Middle removal, after removal, combining inverter Continue while continuing to run with each band filter output signal is detected, if u_{g_j}～u_{g_i-2}The biggest then by u_{g_i-2}From Feedforward compensation voltage u_{g_ff}Middle removal, the rest may be inferred.

Specifically, in instances, ω_cBeing 50 π, n is 7, should add the logical filter of 1,3,5,7 sub-band when the most there is not electric network impedance Ripple device feedforward compensation.

Fig. 6 is that adaptive logic module adjusts u the most automatically_{g_ff}Time (u_{g_ff}=u_{g_1}+u_{g_3}+u_{g_5}+u_{g_7}Time) system open Ring Bode diagram.When electrical network no resistance (β=0), this feedforward compensation will not produce impact to system open loop magnitude-phase characteristics；β increases It is reduced to 11 ° to phase margin when 3, current on line side is easily generated the harmonic current at corresponding frequencies (350Hz) place, and when β increases Unstable to system when 4.And after inventive method normally works, β increases to current on line side i when 3_gIn 7 times and neighbouring time humorous Ripple electric current increases and causes PCC voltage u_gIn 7 times and neighbouring subharmonic voltage increase, Resonance detector module is by u_{g_7}Signal is dashed forward The information increased is sent to adaptive logic module.And then, adaptive logic module judges now should be by u_{g_7}From feed-forward signal u_{g_ff} Middle removal.(u after the work of Resonance detector module when Fig. 7 is β=3_{g_ff}=u_{g_1}+u_{g_3}+u_{g_5}Time) system open loop Bode diagram, Visible, by u_{g_7}From u_{g_ff}After middle removal, phase margin is significantly increased (about 40 °).It can be seen that the employing present invention's is adaptive Answer voltage feed-forward control compensation method that stability that light current off the net grid-connected converter electric current control is greatly improved, thus be conducive to Optimize grid-connected converter stable state and dynamic response.

Fig. 8 give use the present invention self adaptation voltage feed-forward control compensation method time after electric network impedance is uprushed LCL The running of filtering combining inverter and line voltage current waveform figure.When electric network impedance is uprushed to β=5, due to electric current electricity Pressure harmonic wave significantly increases, and the adaptive logic of foundation the inventive method is first by u_{g_7}From u_{g_ff}Middle removal, and then it is each to continue monitoring Secondary band filter exports and continues from u_{g_ff}Middle removal u_{g_5}.It can be seen that use the self adaptation voltage feed-forward control of the present invention Compensation method has significantly decayed light current current on line side harmonic wave off the net, improves current quality.

Dash forward additionally, the combining inverter using control schemes and the inventive method has been carried out benchmark when β=3 The test become.Fig. 9 gives current on line side and the transient response waveform of PCC voltage under control schemes.Due in PCC voltage Comprising the pressure drop on electric network impedance, during current on line side sudden change, PCC voltage certainly exists disturbance, result in dynamic response shown in Fig. 9 In bigger overshoot and serious current/voltage vibration.Have employed the current on line side after the inventive method and PCC voltage As shown in Figure 10, overshoot reduction in transient response and the vibration of current/voltage significantly reduce transient response waveform.

To sum up, the grid-connected converter self adaptation voltage feed-forward control compensation method of the present invention is effectively improved parallel network reverse The device stability when electric network impedance wide variation, is effectively improved grid-connected converter current on line side quality and dynamic Energy.And, the inventive method is without to measure by additionally online or off-line electric network impedance.

The control structure compensated due to voltage feed-forward control in the LCL filtering combining inverter of single-phase and three-phase is similar, And the inventive method can be effectively improved the stability of combining inverter and optimize stable state and dynamic response, thus can be extensive It is applied to various single-phase and three-phase LCL filtering combining inverter electric current control and need not the extra online or electrical network resistance of off-line Anti-measurement.

L filtering, LCL filtering and other form filtering combining inverter to be distinguished as filter construction different, and electrical network Signal and feedforward compensation signal used by electric voltage feed forward compensation inject and control the position in loop all unanimously, and the inventive method can To be effectively improved the stability of combining inverter and to optimize stable state and dynamic response, thus can be widely applied to different filtering Combining inverter electric current under device structure controls and need not online outside plus or off-line electric network impedance to measure.

Owing to the grid type application such as reactive-load compensation, active power filtering, rectification are with the similarity controlled under inversion mode of operation, this Inventive method is also widely applied to the electric current of various grid-connected system and controls and need not online outside plus or the electrical network of off-line Impedance measurement.

To sum up, the inventive method be applicable to single-phase and three-phase L filtering, single-phase and three-phase LCL filtering, single-phase and three-phase other Current on line side or the current transformer side electric current of form filtering grid-connected converter control, and have and fit the strong of wide variation electric network impedance Ying Xing, current on line side are superior in quality, design convenient advantage.

Above example is only the technological thought that the present invention is described, it is impossible to limit protection scope of the present invention with this, every The technological thought proposed according to the present invention, any change done on the basis of technical scheme, each fall within scope Within.

Claims (5)

1. a grid-connected converter self adaptation voltage feed-forward control compensation method, it is characterised in that comprise the steps:

(1) sampling point of common coupling line voltage u_g, and using this point of common coupling line voltage as grid-connected converter self adaptation electricity The input signal that net electric voltage feed forward compensates, described input signal via one group of frequency in parallel be 1, at the n times of fundamental frequency in 3 ... Band filter and produce one group of band filter output signal, be designated as u respectively_{g_1}、u_{g_3}、…u_{g_n}, by this group output signal In each independent band filter output signal be respectively fed to Resonance detector module and adaptive logic module；

(2) each band filter output signal is through Resonance detector module, produces the output letter of signal amplitude or virtual value change Breath, and this information is sent into adaptive logic module；

(3) the output information of Resonance detector module and each band filter output signal are through adaptive logic module, foundation Adaptive logic produces the voltage signal u for feedforward compensation_{g_ff}。

A kind of grid-connected converter self adaptation voltage feed-forward control compensation method the most according to claim 1, it is characterised in that: In described step (3), adaptive logic is: when certain band filter output signal u being detected_{g_i}Amplitude when uprushing, will Band filter output signal u_{g_i}--u_{g_n}From feedforward compensation voltage u_{g_ff}Middle removal；When detecting that certain several band filter is defeated Go out signal u_{g_j}--u_{g_i}Amplitude when uprushing, first by u_{g_i}--u_{g_n}From feedforward compensation voltage u_{g_ff}Middle removal, removes Each band filter output signal is detected by rear continuation, if u_{g_j}--u_{g_i-2}The biggest then by u_{g_i-2}From feedforward compensation voltage u_{g_ff}Middle removal, the rest may be inferred, wherein, and i=3,5 ... n, j=3,5 ... n and j < i.

A kind of grid-connected converter self adaptation voltage feed-forward control compensation method the most according to claim 1, it is characterised in that: For the voltage signal u of feedforward compensation described in step (3)_{g_ff}, under the least electrical network occasion even ignored of electric network impedance, u_{g_ff}Equal to u_{g_1}、u_{g_3}、…u_{g_n}Sum.

A kind of grid-connected converter self adaptation voltage feed-forward control compensation method the most according to claim 1, it is characterised in that: For the voltage signal u of feedforward compensation described in step (3)_{g_ff}, under the electrical network occasion that electric network impedance changes in a big way, with Electric network impedance to be gradually increased, successively from the voltage signal u for feedforward compensation_{g_ff}Middle removal u_{g_n}、u_{g_n-2}、…u_{g_3}。

A kind of grid-connected converter self adaptation voltage feed-forward control compensation method the most according to claim 1, it is characterised in that: For the voltage signal u of feedforward compensation described in step (3)_{g_ff}, at the electrical network occasion that impedance is the biggest, u_{g_ff}Equal to public coupling The first-harmonic ingredient u of some line voltage_{g_1}。